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The use of glochidia in the systematics of the Unionidae (Mollusca: Bivalvia)
Hoggarth, Michael Alan, Ph.D.
The Ohio State University, 1988
UMI 300 N. ZeebRd. Ann Arbor, MI 48106 PLEASE NOTE:
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UMI THE USE OF GLOCHIDIA IN THE SYSTEMATICS OF THE UNIONIDAE
(MOLLUSCA:BIVALVIA)
DISSERTATION
Presented in Partial Fulfillment of the Requirements for
the Degree Doctor of Philosophy in the Graduate
School of the Ohio State University
By
Michael Alan Hoggarth, B.S., M.S.
* * * * * * *
The Ohio State University
1988
Dissertation Committee: Approved by
J. L. Crites
D . H . Stansbery
B. D. Valentine To My Parents My Wife And My Son
ii ACKNOWLEDGMENTS
I am indebted to many for help and encouragement during
this study. I thank Dr. Paul Yokley, Jr., The University of
North Alabama, for introducing me to this fascinating group of animals. To Dr. David H. Stansbery, I express my sincere appreciation for guidance and instruction throughout my doctoral studies, for access to collections at The Ohio
State University Museum of Zoology, and for time spent helping me better understand the Unionidae. I thank Dr.
Stansbery and the other members of my advisory committee,
Drs. John L. Crites and Barry D. Valentine, for their comments and suggestions on this volume. I express my gratitude to Dr. Abbot S. Gaunt for discussions on biomechanics. I thank the following individuals and institutions for access to specimens: Dr. Jack B. Burch, The
University of Michigan Museum of Zoology; Mr. David J.
Heath, The University of Wisconsin Zoological Museum; and,
Mr. Kevin S. Cummings, Illinois Natural History Survey.
Professor Folco Giusti, Istituto di Zoologia dell'Universita di Siena graciously provided glochidia of Unio elongatulus qlaucinus.
iii Gratitude is expressed to Dr. Carol B. Stein for her interest and encouragement during this project. I thank Ms.
Kathy G. Borror for accurate locale data on OSUM specimens, encouragement and friendship. To my fellow graduate students; Dr. Ross F. Feltes and Mr. G. Thomas Watters, I express my sincere appreciation for helpful discussions, collections used in this study, encouragement and friendship. The technical assistance of Mr. Tony Leonardy,
Mr. Dave Stutes and Mr. Dave Dennis is gratefully acknowledged. I express my appreciation to Mr. Thomas E.
Linkous, The Ohio Department of Transportation, for allowing me time away from my normal duties to finish writing this volumn. I would also like to thank The National Science
Foundation for funding a portion of this research (Grant number BSR-8401209).
To my family, I offer sincere thanks. To my mom and dad, Helen J. and Robert S. Hoggarth, I offer my appreciation for enduring faith and the encouragement to try. To my wife, Karen,' I say thank you for understanding my need for time alone or away, and for helping me celebrate the triumphs or understand the disappointments. Your technical ability with software, and your willingness to read and word-process portions of this manuscript are also gratefully acknowledged. To my son, Mark, I say thank you for letting me work when we both would have rather played.
iv VITA
14 July 1955...*...... Born - Arlington, Washington
1977...... B.S., Seattle Pacific College Seattle, Washington
1977-1978...... Assistant Laboratory Manager, Miller Science Learning Center, Seattle Pacific University, Seattle, Washington
1 98 0 ...... M.S., University of North Alabama, Florence, Alabama
1980-1987...... Graduate Teaching Associate, The Ohio State University, Columbus, Ohio
1987-Present...... Environmental Scientist, The Ohio Department of Transportation, Columbus, Ohio
PUBLICATIONS
Hoggarth, Michael A. and Paul Yokley, Jr. 1980. Variations in the characteristics used to distinguish Obovaria unicolor Lea from Obovaria iacksoniana Frierson. Journal of the Alabama Academy of Science, 51:179.
Hoggarth, Michael A. 1982. Variations in the shells of Obovaria iacksoniana (Frierson, 1912) and Obovaria unicolor (Lea, 1845). Bulletin of the American Malacological Union for 1981:29.
Shaw, Ross F. and Michael A. Hoggarth. 1982. Interspecific shell fighting in a hermit crab species ensemble. Proceding of the Fourth International Coral Reef Symposium, 2:623-626.
v Hoggarth, Michael A. 1984. The ultrastructure of smooth muscle cells from the anterior adductor muscle of Lasmiqona costata (Rafinesque, 1820) (Mollusca: Bivalvia: Unionidae). American Malacological Bulletin, 2:84.
Stansbery, David H. and Michael A. Hoggarth. 1984. The distribution of Unionidae in the Calcasieu River in southwestern Louisiana (Bivalvia: Unionoida). American Malacological Bulletin, 2:86.
Hoggarth, Michael A. 1987. Determination of anterior - posterior orientation of glochidia by the examination of glochidial valves present within the umbos of juvenile unionid clams (Mollusca: Bivalvia). Ohio Journal of Science, 87:93-95.
FIELDS OF STUDY
Major Field: Zoology
Studies in Malacology: D. H. Stansbery
Studies in Invertebrate Zoology: J. L. Crites, B. D. Valentine
vi TABLE OF CONTENTS
DEDICATION...... ii
ACKNOWLEDGMENTS...... iii
VITA...... v
LIST OF TABLES ...... ix
LIST OF FIGURES...... X
CHAPTER
I. INTRODUCTION...... 1 Life History of the Unionidae...... 3 The Problem...... 10
II. MATERIALS AND METHODS...... 11 Specimens Examined...... 11 Juvenile Shells ...... 12 Procedures For Light Microscopy...... 13 Procedures For Scanning Electron Microscopy.. 14 Characters Examined...... 19 Statistical Analysis...... 29
III. THE GLOCHIDIA OF THE UNIONIDAE ...... 34 Glochidial Orientation...... 34 Glochidial Descriptions...... 36 Unioninae...... 36 Anodontinae...... 39 Ambleminae...... 122 Lampsilinae...... 139
IV. UNIONID SYSTEMATICS AND THE GLC^IIDIUM...... 253 Attraction, Attachment And Encapsulation 253 Higher Level Systematics...... 265
SUMMARY...... 274
vii APPENDICES A. Proposed Glochidia-Host Relationships...... 278 B. Specimen Data ...... 297 C. Data Used To Construct Figures 4 - 8 ...... 314 D. Binary Data Base ...... 319
LIST OF REFERENCES...... *...... 324
viii LIST OF TABLES
TABLE PAGE
1. Glochidial shell characters used in analysis of relationships between the species of Unionidae. Following each character state is a reference to a figure illustrating the character state...... 20
2. Relative adductor muscle cross-sectional area and index of valve depression from glochidia of the Unionidae. See Appendix B (p. 298) for specimen data and catalog numbers...... 31
3. Proposed glochidia-host relationships for North American Unionidae...... 279
4. Specimen data for glochidia examined...... 298
5. Morphometric data from glochidia examined with scanning electron microscopy. Each entry represents an average from the glochidia examined from a single female unionid rounded to the nearest lOum...... 315
6 . Binary data from glochidia examined with scanning electron microscopy...... 320
ix LIST OF FIGURES
FIGURE
1. Typical life histories of two species of Unionidae: sperm released by the male enters the female through the incurrent aperture. Fertilization occurs within the female and larval development occurs within her modified gills. Following development, the glochidia are released. The glochidium of A. 3 . grandis is released into the water and attaches to the fin of Ambloplites rupestris (Rafinesque, 1817). Here the glochidium is encapsulated and transforms into a juvenile. Following transformation, the young unionid breaks free from the capsule and falls to the substrate. The glochidium of L. r. luteola is held within the marsupium of the female. The marsupia (one right and one left) are positioned between the fish-like mantle flaps. A fish, attracted by the undulations of the mantle flaps, may strike the marsupia, tearing them open and releasing glochidia. These glochidia enter the mouth of the host, are carried to the gills, become encapsulated, and transform into juveniles. When transformation is complete the young unionid falls to the substrate. (Drawing of A. rupestris after Trautman, 1981, and drawings of adult shells of A. 3 . grandis and L, r. luteola after Burch, 1975.)......
2. Subtriangular glochidium of the Anodontinae demonstrating the measurements made to determine the long and short sides of the glochidial valve (arrows). Distance AB - BC; BD, dorso-ventral axis; AE, long side; CE, short side; AM, adductor muscle ......
3. Subelliptical glochidium of the Lampsilinae demonstrating length (L) and height (H). AM, adductor muscle...... Distribution of glochidial valve length for the subfamilies Unioninae and Anodontinae (upper graph, n=47) and the Ambleminae and Lampsilinae (lower graph, n=98). Lsh, short valve length; Lmo, moderate valve length; Llo, long valve length......
Distribution of glochidial valve height for the subfamilies Unioninae and Anodontinae (upper graph, n=47) and the Ambleminae and Lampsilinae (lower graph, n=98). Hsh, short valve height; Hmo, moderate valve height; Hhi, high valve hight ...... *......
Distribution of glochidial hinge length for the subfamilies Unioninae and Anodontinae (upper graph, n=47) and the Ambleminae and Lampsilinae (lower graph, n=98). His, short hinge length; Him, moderate hinge length; Hll, long hinge length......
Distribution of central ligament length for the subfamilies Unioninae and Anodontinae (upper graph, n=45) and the Ambleminae and Lampsilinae (lower graph, n=90). Central ligament refers to the internal portion of the hinge ligament, not the entire hinge ligament. Cls, short central ligament; Cll, long central ligament......
Distribution of central ligament position for the subfamilies Unioninae and Anodontinae (upper graph, n=45) and the Ambleminae and Lampsilinae (lower graph, n=90). Lpp, posterior central ligament position; Lpc, central central ligament position .
Subtriangular glochidium of the Anodontinae demonstrating the directionality of a glochidium. AM = adductor muscle ......
Glochidium of Unio elongatulus glaucinus, MAH:2055; a. exterior valve, bar length = 30um; b. interior valve, bar length - 30um; c. styliform hook, bar length = lOum; d. styliform hook, bar length = lOum; e. exterior valve sculpture, bar length = lum; f. hinge, bar length = 2 Sum...... 11. Glochidium of Anodonta cygnea. OSUM:20911.1; a. exterior valve, bar length =■ S5um; b. interior valve, bar length = 50um; c. interior valve pitting, bar length = Sum; d. styliform hook, bar length = 2 0 um; e. exterior valve sculpture, bar length = lum; f. hinge, bar length = 40um...... 93
12. Glochidium of Anodonta anatina: a. exterior valve, OSUM:20912.2, bar length = SSum; b. interior valve, OSUM:20912.2, bar length = 50um; c. exterior valve sculpture, OSUM:20912.1, bar length = lum; d. styliform hook, OSUM:20912.2, bar length = 20um; e. larval thread, OSUM:20912.2, bar length = 25um; f. larval thread, OSUM:20912.2, bar length = lSum; g. microstylets, OSUM:20912.2, bar length = S u m ...... 94
13. Glochidium of Anodonta berinqiana. OSUM:3 711.1; a. exterior valve, bar length = 45um; b. interior valve, bar length = SOum; c. ventral valve view, bar length - 40um; d. styliform hook, bar length = lOum; e. styliform hook, bar length - lOum; f. styliform hook, bar length = lOum...... 96
14. Glochidium of Anodonta kennerlyia. exterior valve, OSUM:52882.2, bar length = SOum; b. interior valve, OSUM:52882.2, bar length = SOum; c. lateral view, OSUM:52882.3, bar length = SSum; d. styliform hook, OSUM:52882.2, bar length = lSum; e. exterior valve sculpture, OSUM:52882.3, bar length = lum; f. hinge, OSUM:52882.3, bar length = 3Sum. .. 97
15. Glochidium of Anodonta g. grandis, OSUM:38467.10; a. exterior valve, bar length = SSum; b. interior valve, bar length = SSum; c. lateral view, bar length = 5Sum; d. styliform hook, bar length = lSum; e. interior valve pitting, bar length = 15um; f. exterior valve sculpture, bar length = lum ...... 98
16. Glochidium of Anodonta c. cataracta; a. exterior valve, OSUM:52462.27, bar length = SSum; b. interior valve, OSUM:52462.35, bar length = SSum; c. hinge, OSUM:52462.27, bar length = 40um; d. exterior valve sculpture, OSUM:52462.27, bar length - 2um; e. styliform hook, OSUM: 52462 . 27, bar length = 20um...... 99 xii 17. Glochidium of Anodonta doliaris, OSUM:26405; a. exterior valve, bar length = 55um; b. interior valve, bar length = 55uin; c. exterior valve sculpture, bar length = lum; d. styliform hook, bar length = 2 0 u m ...... 100
18. Glochidium of Anodonta implicata, OSUM:52463.7; a. exterior valve, bar length = 50um; b. interior valve, bar length = 4Sum; c. styliform hook, bar length = lOum; d. valve pitting, bar length = 15um; e. hinge, bar length = 25um; f. exterior valve sculpture, bar length = 2u m ...... 101
19. Glochidium of Anodonta suborbiculata. OSUM:1363 4; a. exterior valve, bar length = 40um; b. interior valve, bar length = 40um; c. lateral view, bar length = 40um; d. styliform hook, bar length = lOum; e. valve pitting, bar length = lOum; f. exterior valve sculpture, bar length = 2u m ...... 10 2
20. Glochidium of Anodonta imbecillis; a. exterior valve, UWZY:24971.1, bar length = 50um; b. interior valve, OSUM:9436.2, bar length = 60um; c. styliform hook, UWZY:24971.1, bar length = 15um; d. styliform hook, MAH:435, bar length = 15um; e. hinge, UWZY:24971.1, bar length = 2um; f. exterior valve sculpture, UWZY: 24971.1, bar length = 2um...... 103
21. Glochidium of Anodontoides ferussacianus; a. exterior valve, MAH:989.4, bar length = 50um; b. interior valve, MAH:989.4, bar length = 50um; c. hinge ligament, OSUM:18275.2, bar length = 30um; d. styliform hook, MAH:989.4, bar length = 2 Sum; e. exterior valve sculpture, MAH:989.4, bar length = lum...... 104
22. Glochidium of Simpsonaias ambigua; a. exterior valve, UWZY:22658, bar length = 40um; b. interior valve, UWZY:22662, bar length = 40um; c. lateral view, UWZY:22662, bar length = 4Sum; d. styliform hook, UWZY:22658, bar length = lOum; e. exterior valve sculpture, OSUM:55995, bar length = 2um; f. hinge, UWZY: 22672, bar length = 20um...... 105
xiii 23. Glochidium of Strophitus u. undulatus; a. exterior valve, OSUM:49443, bar length = SOum; b. interior valve, OSUM:52458.4, bar length = 50um; c. lateral view, OSUM:52458.4, bar length - 70um; d. styliform hook, OSUM:52458.4, bar length = 2Gum; e. exterior valve sculpture, OSUM:49443, bar length = lum; f. microstylets, OSUM:52458.4, bar length = lOum. 106 24. Glochidium of Strophitus subvexus. OSUM:36240; a. exterior valve, bar length = 50um; b. interior valve, bar length = 50um; c. exterior valve, bar length = 50um; d. styliform hook, bar length = 2 0 um; e. exterior valve sculpture, bar length = 2 um; f. hinge, bar length = 3Sum...... 107
25. Glochidium of Pressodonta viridis. OSUM:47518; a. exterior valve, bar length = 45um; b. interior valve, bar length = 45um; c. lateral view, bar length = 4Sum; d. styliform hook, bar length = 15um; e. exterior valve sculpture, bar length = 2um; f. interior valve pitting, bar length = lOum...... 108
26. Glochidium of Pressodonta heterodon, OSUM:25106.2; a. exterior valve of immature glochidium, bar length = 45um; b. interior valve, bar length = 70um; c. exterior valve, bar length = 4Sum; d. interior valve, bar length = 60um; e. styliform hook, bar length = lOum; f. exterior valve sculpture, bar length = l u m...... 110
27. Glochidium of Pressodonta compressa; a. exterior valve, OSUM:23179.1, bar length = 4Sum; b. interior valve, OSUM:23179.1, bar length = 45um; c. lateral view, MAH:702, bar length = 70um; d. styliform hook, MAH:702, bar length = 30um; e. exterior valve sculpture, MAH:702, bar length = lum; f. microstylets, MAH:702, bar length = lOum...... 111
28. Glochidium of Pressodonta subviridis; a. exterior valve, OSUM:27131.68, bar length = SSum; b. interior valve, OSUM:27131.68, bar length = 80um; c. exterior valve sculpture, OSUM:27131.66, bar length = lum; d. styliform hook, OSUM:27131.68, bar length = 15um...... 112
xiv 29. Glochidium of Pressodonta holstonia. OSUM:55826.6 ; a. exterior valve, bar length = 45um; b. interior valve, bar length = 40um; c. exterior valve sculpture, bar length = lum; d. styliform hook, bar length = lOum...... 113
30. Glochidium of Pegias fabula; a. exterior valve, OSUM:41308.3, bar length = 55um; b. interior valve, OSUM:41309.1, bar length = 55um; c. exterior valve, OSUM:41308.3, bar length = SSum; d. lateral view, OSUM:41308.3, bar length = 5Sum; e. exterior valve sculpture, OSUM:41308.3, bar length = 2um; f. styliform hook, OSUM:41309.1, bar length = 20um.. 115
31. Glochidium of Alasmidonta undulata, OSUM:52434.4; a. exterior valve, bar length - 60um; b. interior valve, bar length = SSum; c. styliform hook, bar length = 2 0 um; d. interior valve, bar length = SOum; e. exterior valve sculpture, bar length = lum; f. micropoints, bar length = lOum...... 116
32. Glochidium of Alasmidonta marqinata; a. exterior valve, MAH:724.1, bar length - SSum; b. interior valve, MAH:724.1, bar length - 4Sum; c. exterior valve sculpture, MAH:724.1, bar length = lum; d. exterior valve sculpture, MAH: 277.1, bar length = lum; e. styliform hook, MAH:277.1, bar length = 25um; f. hair cell, MAH:724.1, bar length = Sum; g. adductor muscle, MAH:724.1, bar length = Sum; h. mantle cells, MAH:724.1, bar length = lOum; i. larval thread, MAH:724.1, bar length = lOum...... 118
33. Glochidium of Arcidens confragosus. OSUM:52015; a. exterior valve, bar length = 65um; b. interior valve, bar length = 65um; c. styliform hook, bar length = 2 Sum; d. styliform hook, bar length = Sum; e. exterior valve sculpture, bar length = lum; f. microstylets, bar length = Sum; g. hinge, bar length = 40um...... 119
34. Glochidium of Lasmigona costata; a. exterior valve, MAH:585, bar length = SOum; b. interior valve, MAH:279.1, bar length = SOum; c. exterior valve sculpture, MAH:585, bar length = lum; d. styliform hook, MAH:585, bar length = 20um; e. styliform hook, MAH:585, bar length = 2 0 u m ...... 1 2 0 xv 35. Glochidium of Lasmiqona complanata, MAH:278.2; a. exterior valve, bar length = 4Sum; b. interior valve, bar length = 45um; c. styliform hook, bar length = 15um; d. styliform hook, bar length =2 0 um; e. exterior valve sculpture, bar length = lum,* f. exterior valve sculpture, bar length = 2u m ...... 121
36. Glochidium of Magnonaias nervosa: a. exterior valve, OSUM:54178, bar length = 50um; b. interior valve, OSUM:178, bar length - 50um; c. larval thread, OSUM:54178, bar length = 25um; d. larval thread, OSUM:54178, bar length = Sum; e. micropoints, OSUM:54178, bar length = Sum; f. exterior valve sculpture, OSUM:1986:22, bar length = 2um; g. hinge, OSUM: 178, bar length = 20um...... 133
37. Glochidium of Magnonaias boykiniana. OSUM:51107.5; a. exterior valve, bar length = SOum; b. larval thread, bar length = 25um; c. exterior valve sculpture, bar length = lum; d. micropoints, bar length = Sum...... 13 4
38. Glochidium of Plectomerus dombeyana; a. exterior valve, OSUM:53273.3, bar length = 35um; b. interior valve, OSUM:53273.3, bar length = 3Sum; c. exterior valve sculpture and torn exterior valve membrane, OSUM:53273.3, bar length = 2um; d. hinge, OSUM:53273.2, bar length = 2 Sum; e. interior valve pitting, OSUM:42011, bar length = lOum; f. micropoints, OSUM:53273.3, bar length = Sum; g. micropoints, OSUM:42011, bar length = 3um; h. exterior valve sculpture, OSUM:42011, bar length = l u m ...... 135
39. Glochidium of Tritoqonia verrucosa, MAH:654.1; a. exterior valve, bar length = 15um; b. interior valve, bar length = 15um; c. micropoints, bar length = 5um; d. hinge, bar length = 7umj e. exterior valve sculpture, bar length = 2 urn...... 136
xvi 40. Glochidium of Quincuncina infucata; a. exterior valve, OSUM:48537.2, bar length = 40um; b. interior valve, OSUM:48537.2, bar length = 40um; c. micropoints, OSUM:48537.2, bar length = Sum; d. micropoints, OSUM:48537.2, bar length = Sum; e. micropoints, OSUM:48537.1, bar length = 2um; f. exterior valve sculpture, OSUM:48537.1, bar length = 2um; g. hinge, OSUM:48537.1, bar length = 15um...... 137
41. Glochidium of Elliptio dilatata, MAH:946.9; a. exterior valve, bar length = 35um; b. interior valve, bar length = 3Sum; c. exterior valve, bar length = lum; d. interior valve, bar length = lOum; e. micropoints, bar length = Sum; f. hinge, bar length = 20um ...... 138
42. Glochidium of Ptvchobranchus fasciolaris; a. exterior valve, MAH:640.1, bar length = 2Sum; b. interior valve, MAH:640.1, bar length = 2Sum; c. lateral view, MAH:640.1, bar length = 35um; d. ventral valve edge, MAH:651, bar length = 5um; e. exterior valve sculpture, MAH: 651, bar length = lum...... 209
43. Glochidium of Ptychobranchus occidentalis (a-d) and Ptychobranchus greeni (e-h); a. exterior valve OSUM:45361.17, bar length = 35um; b. interior valve, OSUM:45361.14, bar length = 3Sum; c. exterior valve sculpture, OSUM:45361.17, bar length = lum; d. hinge, OSUM:45361.17, bar length = 15um; e. exterior valve, OSUM:19025.2, bar length = 35um; f. interior valve, OSUM:19025.2, bar length = 3Sum; g. exterior valve sculpture, OSUM:19025.2, bar length = lum; h. micropoints, OSUM:19025.2, bar length = 2um...... 211
44. Glochidium of Ptychobranchus subtentum OSUM:43156.5; a. exterior valve, bar length = 3Sum; b. interior valve, bar length = 35um; c. exterior valve sculpture, bar length = lum; d. hinge, bar length = 2 0 um; e. micropoints, bar length = Sum; f. interior valve pitting, bar lenath = 1 0 urn...... 212
xvii 45. Glochidium of Obliquaria reflexa, OSUM:54361.1; a. exterior valve, bar length = 3Sum; b. interior valve, bar length = 3 Sum; c. ventral view, bar length = 25um; d. micropoints, bar length = 7um...... 213
46. Glochidium of Cyprogenia stegaria (a-d) OSUM:6298.21, and Cyprogenia aberti (e-i) OSUM:48067; a. exterior valve, bar length = 30um; b. interior valve, bar length = 30um; c. exterior valve sculpture, bar length = 2um; d. hinge, bar length = 2 0 um; e. exterior valve, bar length = 30um; f. interior valve, bar length = 30um; g. micropoints, bar length = Sum; h. micropoints, bar length = Sum; i. hinge, bar length = 2 0 u m ...... 215
47. Glochidium of Dromus dromas; a. exterior valve, OSUM:20407.1, bar length = 30um; b. interior valve, OSUM: 20407.1, bar length =* 30um; c. interior valve pitting, OSUM:23200.9, bar length = Sum; d. interior valve pitting, OSUM:20407.1, bar length = 3um; e. micropoints, OSUM:23200.9, bar length = 2um...... 216
48. Glochidium of Actinonaias pectorosa: a. exterior valve, OSUM:48748.3, bar length = 35um; b. interior valve, OSUM:48748.3, bar length = 40um; c. lateral view, OSUM:243 37, bar length = 60um; d. micropoints, OSUM:24337, bar length = Sum; e. micropoints, OSUM:24337, bar length - 2um; f. hinge, OSUM:48748.3, bar length = 2 0 um; g. exterior valve sculpture, OSUM: 48748 . 3 , bar length = lum ...... 217
49. Glochidium of Obovaria retusa UMMZ:Uncataloged (a-d) and Obovaria olivaria OSUM:51282.2 (e-h); a. exterior valve, bar length = 40um; b. interior valve, bar length = 40um; c. exterior valve sculpture, bar length = lum; d. hinge, bar length = 2 0 um; e. exterior valve, bar length = 40um; f. interior valve, bar length = 40um; g. exterior valve sculpture, bar length = lum; h. hinge, bar length = lSum.... 219
50. Glochidium of Obovaria subroturda; a. exterior valve, MAH:805.1, bar length = 30um; b. interior valve, MAH:805.1, bar length = 3Sum; c. micropoints, MAH:805.1, bar length = 3um; d. hinge, MAH:659.2, bar length = 15um; e. exterior valve sculpture, MAH:805.1, bar length = lum...... 2 2 0 xviii 51. Glochidium of Obovaria iacksoniana (a-d,g) OSUM:50233.8 and Obovaria unicolor (e,f,h); a. exterior valve, bar length = 30um; b. interior valve, bar length = 30um; c. exterior valve sculpture, bar length = lum; d. hinge, bar length = 15um; e.exterior valve, OSUM:33158, bar length = 30um; f. interior valve, OSUM:3 3158, bar length = 30um; g. micropoints, OSUM:33158, bar length = 2um; h. micropoints, OSUM: 47696. 6 , bar length = 3um...... 222
52. Glochidium of Ellipsaria lineolata, OSUM:1984:14; a. exterior valve, bar length = 4Sum; b. interior valve, bar length = 4Sum; c. lateral view, bar length = 35um; d. micropoints, bar length = Sum; e. hinge, bar length = 15um; f. exterior valve sculpture, bar length = lum...... 223
53. Glochidium of Leptodea fragilis, MAH:626.1; a. exterior valve, bar length = lOum; b. interior valve, bar length = lOum; c. lateral view, bar length = lOum; d. micropoints, bar length = 2um; e. exterior valve sculpture, bar length = lum...... 224
54. Glochidium of Leptodea ochracea, MAH:896; a. exterior valve, bar length = 3Sum; b. interior valve, bar length = 35um; c. lateral view, bar length = 40um; d. hinge, bar length = 15um; e. micropoints, bar length = Sum...... 225
55. Glochidium of Lastena ohiensis, OSUM:54520.1; a. exterior valve, bar length = 2 Sum; b. lateral view, bar length - 30um; c. hinge, bar length = lOum; d. exterior valve sculpture, bar length = 2um; e. micropoints, bar length = Sum...... 226
56. Glochidium of Lastena amphichaena, OSUM:33163.13; a, exterior valve, bar length = 2 Sum; b. micropoints, bar length = Sum; c. hinge, bar length = lOum; d. exterior valve sculpture, bar length = 2um; e. micropoints, bar length = 2urn...... 227
xix 57. Glochidium of Fotamilus alatus; a. exterior valve, OSUM:55465, bar length = SOum; b. interior valve, OSUM:55465, bar length = 50um; c. lateral view, OSUM:55465, bar length = 50um; d. lanceolate hook, OSUM:1983:58, bar length = Sum; e. exterior valve sculpture, OSUM:55465, bar length = lum; f. hinge, OSUM: 5546 5, bar length = 15um...... 228
58. Glochidium of Fotamilus purpuratus. OSUM:15738.2; a. exterior valve, bar length = 50um; b. interior valve, bar length = SOum; c. lateral view, bar length = SOum; d. micropoints, bar length = Sum; e. exterior valve sculpture, bar length = lum; f. hinge, bar length = 15um...... 229
59. Glochidium of Liqumia recta, OSUM:1984:2; a. exterior valve, bar length = 30um; b. exterior valve, bar length = 3Sum; c. lateral view, bar length = 35um; d. micropoints, bar length = 3um; e. micropoints, bar length = Sum ...... 2 30
60. Glochidium of Venustaconcha e. ellipsiformis, MAH:947.2; a. exterior valve, bar length = 35um; b. exterior valve, bar length = 3Sum; c. micropoints, bar length = 2um; d. micropoints, bar length = 2um; e. exterior valve sculpture, bar length = lum; f. interior valve pitting and adductor muscle scar, bar length = lOum; g. hinge, bar length = 15um...... 231
61. Glochidium of Villosa trabalis (a,b,d,e) OSUM:9516.49, and villosa perpurpurea (c) OSUM:16262; a. exterior valve, bar length = 3Sum; b. interior valve, bar length = 3Sum; c. exterior valve, bar length = 40um; d. micropoints, bar length = 2 um; e. exterior valve sculpture, bar length = lum ...... 232
62. Glochidium of Villosa villosa; a. exterior valve, OSUM:45940.7, bar length = 40um; b. interior valve, OSUM:45940.3, bar length = 40um; c. exterior valve, OSUM:45940.7, bar length = 40um; d. interior valve, OSUM:45940.7, bar length = 40um; e. micropoints, OSUM:45940.3, bar length = Sum; f. micropoints, OSUM:45940.3, bar length = 2um; g. exterior valve sculpture, OSUM: 45940. 7 , bar length = lum...... 234
xx 63. Glochidium of Villosa vibex; a. exterior valve, OSUM:24124, bar length = 40um; b. interior valve, OSUM:24124, bar length = 40um; c. adductor muscle insertion, OSUM:54631, bar length - Sum; d. micropoints, OSUM:54631, bar length = Sum; e. exterior valve sculpture, OSUM:54631, bar length = 2um; f. exterior valve sculpture, OSUM:24124, bar length = 2um.... 23 5
64. Glochidium of Villosa i. iris; a. exterior valve, OSUM:55828.4, bar length » 50um; b. interior valve, MAH:641.1, bar length = 40um; c. exterior valve, MAH:641.1, bar length = 40um; d. umbo, MAH:641.1, bar length = 15um; e. exterior valve sculpture, MAH:641.1, bar length = lum; f. micropoints, MAH:641.1, bar length = Sum...... 237
65. Glochidium of Lampsilis t. teres; a. exterior valve, OSUM:51669.2, bar length = 35um; b. interior valve, OSUM:51669.2, bar length = 40um; c. hinge, OSUM:36409, bar length = 15um; d. exterior surface sculpture, OSUM:51669.2, bar length = lum; e. micropoints, OSUM:51669.2, bar length = 5um...... 238
6 6 . Glochidium of Lampsilis t. anodontoides; a. exterior valve, OSUM:35612, bar length = 40um; b. interior valve, OSUM:35612, bar length = 35um,- c. hinge, OSUM: 41762.2, bar length = 15um; d. exterior valve sculpture, OSUM:41762.2, bar length = lum; e. micropoints, OSUM:41762.2, bar length = Sum..... 239
67. Glochidium of Lampsilis r. radiata, MAH:897.1; a. exterior valve, bar length = 45um; b. interior valve, bar length - 4Sum; c. hinge, bar length = 2 0 um; d. exterior valve sculpture, bar length = lum; e. micropoints, bar length = lOum...... 240
6 8 . Glochidium of Lampsilis abrupta; a. exterior valve, OSUM:13 30 3, bar length = 40um; b. interior valve, OSUM:38841, bar length = 40um; c. micropoints, OSUM:13303, bar length = 2um; d. micropoints, OSUM:38841, bar length = 2um; e. exterior valve sculpture, OSUM:13303, bar length = lum; f. hinge, OSUM:13303, bar length = 15um...... 241
xxi 69. Glochidium of Lampsilis hiqqinsi, OSUM:49024.1; a. exterior valve, bar length = 35um; b. interior valve, bar length = 3Stun; c. lateral valve view, bar length = 35um; d. micropoints, bar length = 2 um,* e. exterior valve sculpture, bar length = lum; f. hinge, bar length - 15um...... 242
70. Glochidium of Lampsilis ovata. OSUM:43164.1; a. exterior valve, bar length - 40um; b. interior valve, bar length = 40urn; c. micropoints, bar length = Sum; d. exterior valve sculpture, bar length = lum; e. hinge, bar length = 20um; f. hinge, bar length = 20um... 243
71. Glochidium of Lampsilis ventricosa; a. exterior valve, MAH:954.6 , bar length = 40um; b. interior valve, MAH:954.3, bar length = 40um; c. lateral view, OSUM:44619, bar length = 40um; d. micropoints, MAH:954.3, bar length = 2um; e. micropoints, MAH:954.4, bar length = 2um; f. exterior valve sculpture, MAH:954.1, bar length = lum; g. hinge, MAK:954.6, bar length = 15um...... 244
72. Glochidium of Lampsilis breviculata; a. exterior valve, OSUM:45363.35, bar length = 40um; b. interior valve, OSUM:45363.20, bar length = 40um; c. hinge, OSUM:45363.50, bar length = 15um; d. exterior valve sculpture, OSUM:4 5363.50, bar length = lum; e. micropoints, OSUM:45363.35, bar length - 5um 245
73. Glochidium of Lampsilis crocata; a. exterior valve, OSUM:42060.1, bar length = 40um; b. interior valve, OSUM:42060.1, bar length = SOum; c. lateral view, OSUM:54485.1, bar length = 50um; d. micropoints, OSUM:54485.1, bar length = 2um; e. exterior valve sculpture, OSUM:54485.1, bar length = lum; f. micropoints, OSUM:42060.1, bar length - 5urn...... 246
74. Glochidium of Lampsilis cariosa, OSUM:54500; a. exterior valve, bar length = 4Sum; b. interior valve pitting and adductor muscle scar, bar length = 15um; c. exterior valve sculpture, bar length = lum; d. micropoints, bar length = Sum ...... 247
xxii 75. Glochidium of Lampsilis fasciola; a. exterior valve, OSUM:5 5033.2, bar length = 4Sum; b. interior valve, OSUM:55033.2, bar length = 45um; c. lateral view, OSUM:25467, bar length = 40um; d. micropoints, OSUM:55033.2, bar length = Sum; e. exterior valve sculpture, OSUM:55033.2, bar length = lum; f. hinge, OSUM: 55033 . 2, bar length = 15um...... 248
76. Glochidium of Epioblasma triguetra. MAH:588.1; a. exterior valve, bar length = 3Sum; b. interior valve, bar length = 40um; c. interior valve, bar length - 40um; d. supernumerary hook and micropoints, bar length = 2um; e. micropoints, bar length = Sum...... 249
77. Glochidium of Epioblasma brevidens, OSUM:16173; a. exterior valve, bar length = 40um; b. interior valve, bar length = 40um; c. supernumerary hook and micropoints, bar length = Sum; d. adductor muscle scar, bar length = 2 0 um; e. exterior valve sculpture, bar length = lum; f. hinge, bar length = 25um...... 250
78. Glochidium of Epioblasma capsaeformis. OSUM:42007; a. exterior valve, bar length = 35um; b. interior valve, bar length = 35um; c. micropoints, bar length = Sum; d. supernumerary hook, bar length = 5um; e. interior valve, bar length = 35um; f. exterior valve sculpture, bar length = lum; g. hinge, bar length - 25um...... 251
79. Glochidium of Epioblasma torulosa rangiana; a. exterior valve, MAH:632.1, bar length = 40um; b. interior valve, MAH:632.1, bar length = 35um; c. interior valve, MAH:632.1, bar length - 35um; d. hinge, MAH:701, bar length = 25um; e. micropoints and supernumerary hooks, MAH:701, bar length = Sum; f. exterior valve sculpture, MAH:632.1, bar length = lum...... 252
80. Adductor muscle size increases with increasing glochidial valve depression. Closed circles represent the Anodontinae, triangles represent the Ambleminae, and open circles represent the Lampsilinae. The glochidium of Peqias fabula was not plotted but was included in regression analysis (see Table 2 for the data used to construct this figure)...... 260
xxiii 81. Principal Components Analysis of selected glochidia. a, Ueg; b, Acy; c, Abe; d, Akel; e, Agrl; f, Aip; g, Asu; h, Aiml; i, Sami; j, Sunl; k, Phe; 1, Pfbl; m, Aun; n, Lcsl; A, Mne; B , Pdo; c, Edi; D, Pfal; E, Pgr; F, Ore; G, Cst; H, Cab; I, Ddrl; J , Apel; K, Obr; L, Eli; M # Lfr; N, Loc; O, Loh; P, Pall; Q, Lre; R, Vtr; S, Vvll; T, Virl; U, Ltel; V, Lvel; W, Etr; X , Eral. See Table 5 (Appendix C) for the identity of taxa abbreviated here...... 267
82. Principal Components Analysis of selected anodontine glochidia. A, Ueg; B, Acy; C, Aanl; D, Abe; E, Akel; F, Agrl; G, Aip; H, Asu; I, Aiml; J, Sami; K, Sunl; L, Phe; M, Pfbl; N, Aun; 0, Lcsl. See Table 5 (Appendix C) for the identity of taxa abbreviated here... 269
83. Principal Components Analysis of selected lampsiline glochidia. A, Pfal; B, Pgr; C, Ore; D, Cst; E , Cab; F, Ddrl; G, Apel; H, Obr; I, Lre; J, vtr; K , Vvll; L, virl; M, Ltel; N, Lvel; O, Etr; P, Eral. See Table 5 (Appendix C) for the identity of taxa abbreviated here... . 271
xxiv CHAPTER I
INTRODUCTION
Advances in the classification of a group of organisms are often the result of seeing characters in fundamentally different ways, rather than examining fundamentally different characters. Often the insight upon which a change in classification occurs is proceeded by the examination of abundant material, close attention to character states, and an understanding of the selective advantage of the characters examined. The result is a system of classification that approximates the evolution of the group, referred to as a natural system of classification (Mayr,
1969:61).
Ortmann (1912) demonstrated how important an understanding of selective advantage is when interpreting characters in systematics. The soft parts of many of the
Unionidae, or pearly freshwater mussels, had been examined and described (Lea, 1834, 1858, 1860, 1862, 1863, 1868,
1874). Furthermore, characters of the soft parts had begun to be used in unionid taxonomy (Sterki, 1895, 1898, 1903;
Simpson, 1900). However, Ortmann's work (1910a, 1910b,
1910c, 1910d, 1911, 1912, 1919) is set apart from the rest 1 2 by his clear interpretation of evolutionary trends in
significant biological structures. In regard to the
Lampsilinae, but characteristic of his character analysis, he wrote:
"In order to understand the structure of the Lampsilinae, and their further differentiation, we must recall their essential characteristics and their purpose. We have seen that the soft parts are accommodated to two functions: (1 ) owing to the extended breeding season (in bradytictic forms) that of securing the proper aeration of the gravid marsupium, (2 ) the discharge of the glochidia through the edge of the marsupium. .. Very likely the adaptations of these two peculiar functions are connected in a degree. We see that it is the general tendency among the Lampsilinae to move the marsupium toward the edge of the gill, and even beyond the latter. This has the effect that it is removed, more or less, from the natural outlets, and comes in close contact with the outer water flowing over the gills. Under these conditions it is easily understood that the habit was acquired to discharge the glochidia not by the long way (the suprabranchial canals) , but by the shortest, by making them go through holes in the edge of the marsupium.” (1912:301) with such a clear understanding of evolutionary process in regard to structures of biological significance, it is not surprising that the classification of the Unionidae proposed by Ortmann (in its most complete form, 1912) has been largely substantiated by electrophoretic analysis (Davis and
Fuller, 1981) and karyology (Jenkinson, 1983), and is reflected in many modern schemes of unionid classification
(See Stansbery and Borror, 1983 for example).
The larval stage of the Unionidae, called a glochidium, has not been overlooked as a source of taxonomic characters 3 (Sterki, 1903; Ortmann, 1912; Morrison, 1955). However, the emphasis of much of the study of glochidia has been on the determination of the hosts (see Appendix A). The objective of this study is to use scanning electron microscopy to examine the fine structure of the glochidial valve and to make additional glochidial structures available for unionid systematics. Young and Williams (1984) have demonstrated that mortality of glochidia following release from female
Margaritifera marqaritifera (Linnaeus, 1758) is 99.9%, and I will further suggest that since mortality is high, natural selection during this period of the unionid life cycle will likewise be high. The following account of the life history of the Unionidae not only demonstrates that a better understanding of the glochidium has led to a better understanding of the biology of the Unionidae, but that a better understanding of the glochidium might further our understanding of the systematics of this family.
Life History of the Unionidae
The Unionacea (families: Unionidae, Margaritiferidae,
Hyriidae) have an unusual mode of development, well suited to life in a flowing water environment. Unlike most marine bivalve young and the larvae of the freshwater genus
Corbicula. glochidia do not continue development as free swimming members of the plankton. Neither are they released by the female as free living miniatures of the adults, as in 4 the family Sphaeriidae. Instead the young are held within
the gills of the female and are released as potential
parasites. The development of this parasitic relationship
between aquatic vertebrate and mollusk has affected unionid
distribution, larval and adult morphology, and rates of
speciation (Kat, 1984).
Leeuwenhoek (1722) made the first substantial
observations of the glochidium in 1695, and at that time
correctly interpreted these tiny bivalves as the young of
the mollusk. He also observed limited development of the
larvae and saw the characteristic snapping behavior they
display when mature. It does not appear that he ever
doubted that these tiny mollusks, which had developed within
the gills of the female, were her young. However, he, like
so many others during the century and a half to follow, was
unable to provide an environment outside of the female where
development could continue. This combined with the facts
that these tiny mollusks were almost identical in both
Anodonta and Unio, numbered within the gills of the larger
mollusk by the thousands, and had structures either real or
imagined that were quite different from those of the larger mollusk, led some to believe that the small shelled animals
were not the young of the larger mollusk but a parasite.
The tiny bivalved parasites were given the name Glochidium
parasiticum (Rathke, 1797). 5 Our story might have ended here if not for the observations of Carus and Leydig. Carus (1832) watched the brightly colored ova of Potainida littoralis (Cuvier, 1797) pass from the oviduct to the outer gills of the female mollusk. Continued observation demonstrated that the animal known as G. parasiticum was not a species separate from the larger mollusk but the larval stage of that mollusk. Carus was unable to keep the young alive outside of the female, but his observations corrected the Glochidium Theory.
Continued progress in our understanding of the life history of the Unionidae was the result of Leydig*s (1866) discovery of glochidia embedded in the fins of a fish. With this developmental mystery solved, investigators began to infect fish with glochidia. Their primary objective was to document the changes that occur during parasitism when the glochidium transforms into a juvenile (Braun, 1878; Schmidt,
1885; Schierholz, 1878, 1888; and Harms, 1907a, 1907b,
1907c, 1908, 1909). These studies also demonstrated that artificial infection could be used to indicate the susceptibility of fish to glochidia. Fueled by the commercial importance of North American unionid shells in the button industry, and the dwindling supply of those shells, the staff of the U.S. Bureau of Fisheries began to use artificial infection to determine the hosts for commercially important species (Lefevre and Curtis, 1910, 6 1912; Coker and Surber, 1911; Surber, 1912, 1913, 1915;
Howard, 1912, 1914a, 1914b, 1914c).
Hosts for about one forth of North American unionids
have been proposed. Appendix A is an update of a table
prepared by Fuller (1974) with two important additions; 1. a notation as to the type of evidence presented for the
relationship, 2. a complete citation for the evidence. The table in Appendix A demonstrates the tenuous nature of many of the proposed hosts. There are many examples of laboratory or field evidence indicating a host-parasite relationship. There are a few examples where a relationship was based on inference (a species of unionid becoming established in a fish pond), and others where no evidence was given. There are only a few examples of laboratory and field studies corroborating each other. Two examples of probable host-parasite relationships are shown in Figure 1.
Upon first inspection, Figure 1 appears to show two very similar life histories. Sperm, produced by the males, are released into the water and become available to any female that happens to be in a position to draw the sperm through the incurrent aperture. Generally the female must be downstream from the male. Fertilization occurs either while the eggs are passing from the oviduct to the gills of the female, or after the eggs have been deposited in the gills. Nonetheless, it is within the gills, or a portion of the gills, where further larval development occurs. Figure 1. Typical life histories of two species of Unionidae: sperm released by the male enters the female through the incurrent aperture. Fertilization occurs within the female and larval development occurs within her modified gills. Following development, the glochidia are released. The glochidium of A. 3 . grandis is released into the water and attaches to the fin of Ambloplites rupestris (Rafinesque, 1817). Here the glochidium is encapsulated and transforms into a juvenile. Following transformation, the young unionid breaks free from the capsule and falls to the substrate. The glochidium of L. r. luteola is held within the marsupium of the female. The marsupia (one right and one left) are positioned between the fish-like mantle flaps. A fish, attracted by the undulations of the mantle flaps, strikes the marsupia, tearing them open and releasing glochidia. These glochidia enter the mouth of the host, are carried to the gills, become encapsulated, and transform into juveniles. When transformation is complete the young unionids fall to the substrate. (Drawing of A. rupestris after Trautman, 1981, and drawings of adult shells of A. 3 . grandis and L. r. luteola after Burch, 1975.)
7 | Ambloplites rupestris Juvenile
grandis grandis Lampsihs radiata luteola
Mussel Bed
Figure 1. Typical life histories of two species of Unionidae. oo 9 Glochidia must be released from the marsupial gill, come in
contact with a suitable host (generally a fish), and become
encapsulated by host tissue if development is to continue.
Direct development has been reported for Anodonta imbecillis
Say, 1829, by Howard (1914d) and Strophitus undulatus (Say,
1817), by Lefevre and Curtis (1911), however both of these
species have also been found to utilize fish hosts (see Appendix A).
It is at the point of release from the female where the
differences in the life cycles of the two unionids pictured
in Figure 1 become apparent. Not only are the larvae
themselves very different but so are their sites of eventual
parasitism and the way in which they gain access to their
host. The relatively large, subtriangular glochidium of
Anodonta grandis grandis bears a hook on the ventral margin
of each valve. If this glochidium clamps down on the fin of a passing fish and pierces the fin epithelium it may become encapsulated by host tissue. The smaller, subelliptical glochidium of Lampsilis radiata luteola lacks the hooks. If this glochidium is taken in through the mouth of its host, travels to the gills and clamps down on a gill filament, irritating the gill epithelium, it too may become encapsulated by host tissue. Attraction devices, such as the mantle flaps of Lampsilis (Figure 1), probably facilitate the exchange of glochidium from unionid to fish
(Morrison, 1973). 10 The dissimilarities in these life histories reveal
three periods when selection might be acting upon the
glochidium; 1 . during release from the female, 2 . during
initial contact with the host, and 3. during encapsulation.
The selective advantage of glochidial structures might be
understood, therefore as they facilitate one or more of the
processes related to each of these periods; attraction of
the host, attachment to the host, and induction of
encapsulation.
The Problem
The question of how parasitic larvae have evolved in
the Unionacea has been dealt with adequately (Coker and
Surber, 1911; Howard and Anson, 1922; Arey, 1932a, 1932b;
Kat, 1984). The capsule provides a stable environment where
transformation can occur, a ready source of nutrients
(whether used or not), and protection from predators and from being washed or tumbled downstream. Furthermore, the host may function as a dispersal mechanism, and may release the newly transformed juvenile into a suitable environment
(assuming the habitat requirements of the host remain the same from the time of attachment to release). The selective advantage of glochidial structures have not received the same inquiry. This study examines glochidial characters and suggests a classification of the Unionidae that reflects the evolution of these characters. CHAPTER II
MATERIALS AND METHODS
Specimens Examined
Appendix B lists the specimen data from the materials examined during this study; juvenile shells with glochidial valves visible upon the umbo (indicated by '), glochidia viewed by light microscopy (indicated by #), and glochidia examined with Scanning Electron Microscopy (SEM) (indicated by *). Glochidia were removed from the marsupia of 209 female unionids representing 98 nominal species from 33 genera. Forty-three lots of material were processed from specimens collected or received during this study. These were given MAH catalog numbers. These specimens will be processed into the collection at The Ohio State University
Museum of Zoology, however they will retain their MAH catalog numbers so that future investigators will be able to locate the material described here. The remaining specimens were located within the collections of unionid mollusks deposited at The Ohio State University Museum of Zoology
(OSUM), University of Michigan Museum of Zoology (UMMZ),
University of Wisconsin Zoological Museum (UWZY), and The
Illinois Natural History Survey (INHS). 11 12 Glochidia removed from the marsupia of female unionids were preserved (for freshly collected specimens) and stored in a solution of 80% alcohol, 5% glycerin, 15% water (AGW).
Each vial of glochidia was labeled with the catalog number of the female from which the sample came. Subsamples of glochidia taken from a vial for dehydration in acetone, and subsamples of these placed on a stub for viewing in the SEM, were also labeled with the catalog number of the female mollusk. Therefore, each glochidium examined can be traced back to its maternal parent.
Juvenile Shells
Juvenile shells of six species of the subfamily
Anodontinae were examined with light microscopy. Glochidial valves found upon examination of the umbos of these juvenile shells were photographed using a Pentax 35 mm camera equipped with extension rings, bellows and a 55 mm Takumar lens (see Hoggarth, 1987). The outline of each glochidial valve was measured from these photographs. Measurements were made from the middle of the dorsal margin to the base of the hook at the ventral terminus along each lateral margin (Figure 2). Since anodontine glochidia are asymmetrical about the dorso-ventral axis this produced two measurements of unequal length. One lateral margin was called the long side, the other, the short side. This study was made to determine the anterior-posterior orientation of 13
C B A
E D
Figure 2. Subtriangular glochidium of the Anodontinae demonstrating the measurements made to determine the long and short sides of the glochidial valve (arrows). Distance AB - BC; BD, dorso-ventral axis; AE, long side; CE, short side; AM, adductor muscle.
the shell of the glochidium. Orientation of the glochidial shell was determined by its relationship to the known anterior-posterior orientation of the juvenile shell.
Procedures for Light Microscopy
All glochidia excised from the gravid marsupia of female unionids were examined using a Bausch and Lomb
Dissecting Microscope to determine if the glochidial valves were gaping enough to be cleaned for examination with the
SEM (the cleaning procedure is outlined below). Glochidia that were too tightly clamped to be cleaned for SEM were measured using an ocular micrometer calibrated to 0.05mm 14 and used to determine the area of the glochidial adductor
muscle and valve.
Unlike adult unionids, that have anterior and posterior
adductor muscles, each glochidium has a single adductor muscle. Figure 3 demonstrates the measurements that were
taken from each of 134 glochidia from 57 species. Valve area and adductor muscle cross-sectional area were obtained
from projections of micrographs of glochidia on the screen of a Hewlett Packard 9874A Digitizer. Glochidial micrographs were taken with a Pentax 35 mm camera equipped with an adapter that fit over the eyepiece of the Bausch and
Lomb dissecting microscope. The area of each valve and adductor muscle was calculated using HP Digitize Software with an HP 9825B Computer.
Procedures for Scanning Electron Microscopy
Preserved and freshly collected glochidia were cleaned by the removal of the glochidial soft parts. Only glochidia that had valves gaping apart (in the case of the preserved material) or that were actively snapping their valves (in the case of freshly collected glochidia) were processed for the SEM.
The initial step in cleaning was to wash the glochidia in three changes of distilled water. Each sample was suspended in distilled water and then allowed to settle.
After the glochidia had settled, or a majority of them had 15
AM
L
Figure 3. Subelliptical glochidium of the Lampsilinae demonstrating length (L) and height (H). AM, adductor m u s c l e .
settled, the supernatant was removed using a Pasteur pipet.
Generally, the glochidia settled to the bottom of the vial within 10 - 15 seconds whereas small pieces of the marsupium or the matrix, within which the glochidia may be found within the marsupium, were still suspended. These impurities were removed with the supernatant. Preserved glochidia were then cleaned using a solution of trypsin in
Sorensen's Phosphate Buffer, pH 7.00 (1% aqueous trypsin).
Previous investigations of glochidia using the SEM employed only freshly collected material from which the soft parts were removed by the application of a mild basic solution (Calloway and Turner, 1979) or preserved material from which the soft parts were not removed (Giusti, 1973; 16 Giusti et al. , 1975; Clarke, 1981a, 1985; Rand and Wiles,
1982). No practical method for the removal of the preserved
soft parts had been developed. However, I found that a mild
solution of trypsin will digest the preserved soft parts
leaving the valves of the glochidium intact. The exact procedure and time required for the production of usable specimens varied with the sample, however, and because of this the procedure outlined below is flexible to allow for differences in preservation, initial valve gape, and amount of extraneous material in the sample.
Partial Trypsin Digestion Procedure For Glochidia Preserved
in AGW or Buffered Formalin
1. Following the final rinse in distilled water, place specimens in 1 0 ml of 1 % aqueous trypsin solution and mix thoroughly. The sample can best be mixed by drawing and expelling the liquid in the vial into a pipet 10-15 times.
The action of the rapidly moving liquid may dislodge the soft parts from the valves, reducing the time required to clean the sample.
2. Place a labeled cap on the vial and put it in an oven at 37° Centigrade. View the sample every 15 minutes and remove the sample when the valves begin to gape widely.
I found that it was best to discontinue the digestion process as soon as the first valves began to open rather than after all valves had opened. 17 3. To check a sample for gaping specimens, swirl the
liquid in the vial and watch the glochidia as they settle.
As the tissues are digested the adductor muscle will detach
from the valves and the valves will gape at an angle
approaching 180° from each other. These glochidia will
descend much more slowly than glochidia with intact adductor
m us c l e s .
4. Remove the sample from the oven and pipet the
supernatant, being very careful not to stir up the glochidia
on the bottom of the vial. Remove the foam on the surface
of the liquid first, then discard the liquid using a pipet.
5. Wash the glochidia in distilled water and view with
a dissecting microscope to determine the extent of the
digestion process. If the valves of the glochidia are
gaping and the soft parts are no longer attached to one
valve, even though they remain in most or all glochidia, it
is best to stop the digestion process at this point.
Continued digestion with trypsin may result in the the
digestion of the protiens of the hinge ligament and the
disassociation of the glochidial valves. If the adductor muscle is still attached to both valves repeat steps 1-5.
6 . Wash the glochidia as before and mechanically
dislodge the remaining soft parts. This is done by drawing
a large number of glochidia into a pipet and expelling them
20-30 times per wash. Keep in mind that it is not necessary
to remove the soft parts from all specimens. 18 Freshly collected glochidia were cleaned after Calloway
and Turner (1979). These glochidia were initially washed as above, with two drops of IN NaOH added to the final wash
(10ml). The glochidia were allowed to stand in this slightly basic solution for ten minutes and then washed in three changes of distilled water.
Cleaned glochidia, whether freshly collected or preserved, were then dehydrated in an ascending gradation of acetone (10%, 30%, 50%, 70%, 90%, 95%, 100%, 100%) and stored in Borosilicate Glass Scintilation Vials (VWR
Scientific) in the final acetone wash. Subsamples of these glochidia were processed for the SEM. Glochidia were air dried on a clean glass slide and mounted on double stick tape (3M) on 13 mm aluminum stubs. The tape was rimmed with silver paint and then the entire stub was placed in a vacuum desiccator for 24 hours. Critical point drying was found to be unnecessary. Following desiccation, the specimens were coated with 30 um of gold-palladium in a Hummer VI sputter
Coater, and then viewed in a Cambridge Stereoscan S4-10
Scanning Electron Microscope or a Hitachi S-500 Scanning
Electron Microscope. An acceleration voltage of 20 kv was used. Micrographs of glochidia were taken using
Technical-Pan Black and White roll film (Kodak) and Type-55
Positive-Negative film (Polaroid). After viewing the glochidia, and removing the stub from the SEM, the post of the stub was pushed into the inside surface of the cap of a 19 two dram Opticlear Flint Glass Vial (VWR Scientific). The labeled vial was then pushed onto the cap and the entire unit (cap, stub, vial and label) was placed in a desiccator.
Stubs stored as described above produced good micrographs as much as two months following initial processing and viewing
(see Figs. 52d taken on 14 February 1986 and 52a taken from the same stub on 4 April 1986).
Characters Examined
Table 1 lists the characters examined. Each character is defined in terms of two or more states or expressions of that character. For example, dorsal alae (character) are absent, short or long (character states). Measurements were made directly from SEM micrographs with care taken when glochidia were placed on the stub to ensure that some were flat in respect to the stub surface (not tilted).
Micrographs of these glochidia were taken at 0° tilt.
Length - Glochidial valve length was measured as the greatest distance from anterior to posterior margins. This measurement was made parallel to the hinge (Figure 3). The distribution of glochidial valve length was plotted and cuts made to define character states. Plotting the unionine and anodontine glochidia separately from the amblemine and lampsiline glochidia emphasized gaps in the distribution
(Figure 4). Appendix C contains the data used to construct
Figures 4 through 8 . 20
Table 1. Glochidial shell characters used in analysis of relationships between the species of Unionidae. Following each character state is a reference to a figure illustrating the character state.
1. Length 8 . Dorsal alae a. short (53a) a. absent (43a) b. moderate (64a) b. short (54a) c. long (24a) c. long (69a) 2. Height 9. Microstylets a. short (39a) a. absent (60c) b. moderate (65a) b. many unorganized (22d) c. high (31a) c. one distal row (20d) 3. Hinge length d. two distal rows (23d) a. short (55c) e. many distal rows (35d) b. moderate (71g) 10. Micropoints c. long (Ilf) a. lanceolate (36e) 4. Central ligament length b. lamellate (56e) a. short (52e) c. coronal (40e) b. long (16c) 11. Micropoint organization 5. Central ligament position a. unorganized (43h) a. posterior (14f) b. horizontal rows (78c) b. central (57f) c. broken vertical rows 6 . Valve shape (66e) a. subelliptical (43b) d. complete vertical rows b. depressed subelliptical (52d) (78b) 12. Hook c. subrotund (45b) a. absent (62d) d. subspatulate (70b) b. styliform (32e) e. fabelliform (47b) c. supernumerary (77c) f. subligulate (52b) d. lanceolate (57d) g. ligulate (58b) 13. Exterior surface sculpture h. subtriangular (12b) a. rough (75e) i. lachrimiform (18b) b. beaded (22e) j. pyriform (34b) c. rosette (33e) k. depressed pyriform (27b) d. loose looped (16d) 1. quadrate (30b) e. ribbed loose looped 7. Lateral valve gape (1 2c) a. absent (71c) f. tight looped (30e) b. present (57c) g. vermiculate (58e) 21 H e i g h t . - Glochidial valve height was measured as the greatest distance from dorsal to ventral margins. This measurement was made perpendicular to length (Figure 3 ).
Figure 5 gives the distribution of glochidial valve height.
Hinge length - The hinge is the portion of the shell where right and left valves join. It was measured in a straight line from the points were the dorsal margins intersects the anterior and posterior margins regardless of whether the hinge was curved or straight. Figure 6 shows the distribution of glochidial hinge length.
Hinge ligament length - The hinge ligament is a springlike structure that tends to abduct the valves of the bivalve mollusk. In the glochidium the hinge ligament extends the entire length of the hinge. A portion of the ligament can be seen when viewing the valve externally and another portion can be viewed internally. Herein, central ligament refers to the central portion of the hinge ligament or that portion that can be viewed internally. Posterior ligament refers to the posterior portion of the hinge ligament, measured from the posterior margin of the hinge to the posterior margin of the central ligament. Anterior ligament is the portion of the hinge ligament from the anterior margin of the hinge to the anterior margin of the central ligament. Figure 7 shows the distribution of the central ligament length.
Central ligament position - Central ligament position was found by adding one half the central ligament length to 22
Lsh Lmo Llo 10 —
5 — Number of 0 - XI M a glochidia
20 -
10 — |
5 -
- run R 0 TTTTT i i— i— — i— i— r T 0 50 100 150 200 250 300 350 400 450 Valve Length (urn)
Figure 4. Distribution of glochidial valve length for the subfamilies Unioninae and Anodontinae (upper graph, n=47) and the Ambleminae and Lampsilinae (lower graph, n=98). Lsh, short valve length; Lmo, moderate valve length; Llo, long valve length. 23
10 —
Number of 0 glochidia 15 —I
10
5
0 100 150 200 250 300 350 400 450 Valve Height (um)
Figure 5. Distribution of glochidial valve height for the subfamilies Unioninae and Anodontinae (upper graph, n=47) and the Ambleminae and Lampsilinae (lower graph, n=98). Hsh, short valve height; Hmo, moderate valve height; Hhi, high valve hight. 24
10 His Him Hll
5 Number of 0 glochidia 25 —
20 —
15 -
10 —
5 —
0 0 50 100 150 200 250 300 350 400 450 Hinge Length (urn)
Figure 6 . Distribution of glochidial hinge length for the subfamilies Unioninae and Anodontinae (upper graph, n=47) and the Ambleminae and Lampsilinae (lower graph, n=98). His, short hinge length; Him, moderate hinge length; Hll, long hinge length. 25
15 — Cls Cll
10 —
5 — Number of 0 - glochidia 45 —
40 —
35 —
30 —
25 —
20 —
15 —
10 —
5 —
r I T T i— r 50 100 150 200 250 300 350 400 Central Ligament Length (um)
Figure 7. Distribution of central ligament length for the subfamilies Unioninae and Anodontinae (upper graph, n=4 5) and the Ambleminae and Lampsilinae (lower graph, n=90). Central ligament refers to the internal portion of the hinge ligament, not the entire hinge ligament. Cls, short central ligament; Cll, long central ligament. 26 the length of the posterior ligament and then dividing by
the length of the hinge. The product was expressed as %
length of the hinge from the posterior end of the hinge
(Figure 8 ).
Valve shape - Valve shape refers to the outline of the
shell when viewed sagittally (the plane bisecting anterior
and posterior). The terms used to describe valve shape have
been loosely defined in the past. The terms for valve shape
used in this study are subelliptical, subrotund,
subspatulate, depressed subelliptical, fabelliform,
subligulate, ligulate, subtriangular, lachrimiform,
pyriform, depressed pyriform, and quadrate.
Lateral valve gape - With the valves fully adducted
some species of glochidia were found to possess anterior and posterior valve gape. This character was expressed as
either absent or present.
Dorsal alae - This structure was found at the dorsal- anterior and dorsal-posterior margins of most lampsiline glochidia. They can best be described as arch-like extensions of the glochidial valve. This character was expressed as absent, short or long.
Nlcrostylets - Clarke (1981a) proposed the term microstylet for the larger (>1.0 urn long) points on the ventral margin of the glochidial valve. Microstylets were absent, many and unorganized, arranged in one distal row on 27
Lpp Lpc 10 —
5 — I Number of 0 - XL XL aa glochidia 15 — I
10 —
5 — T T ~T T T T m r 10 15 20 25 30 35 40 45 50 Central Ligament Position (% distance from posterior margin)
Figure 8 . Distribution of central ligament position for the subfamilies Unioninae and Anodontinae (upper graph, n=45) and the Ambleminae and Lampsilinae (lower graph, n=90). Lpp, posterior central ligament position; Lpc, central central ligament position. 28 the hook, arranged in two distal rows on the hook, or arranged in many distal rows on the hook.
Micropoints - Clarke (1981a) used the term micropoints for the small (<1 . 0 urn long) points on the ventral margin of the glochidial valve. Micropoints were either: 1 ) lanceolate, arising as single attenuate points from the ventral margin of the valve; 2 ) lamellate, arising as single plate-like points; or 3) coronal, with three to seven attenuate points arising from a common base.
Micropoint organization - Micropoints were unorganized, arranged in horizontal rows, arranged in broken vertical rows, or arranged in complete vertical rows.
Hook - As pointed out by Clarke (1981a), this term has been used indiscriminately to apply to independently derived structures that serve a similar function, that of piercing the tissues of the host. He proposed using the term stylet to refer to the complex hook of the anodontine glochidia.
In this study the glochidial hook was either: 1) absent; 2) styliform, a V-shaped extension of the ventral margin of the glochidium; 3) lanceolate, a recurved attenuate extension at each corner of the ventral margin of the glochidia of
Fotamilus; or 4) supernumerary, the straight and sharply pointed hook found in an area along the ventral margin that usually lacks microsculpture. Although within the size range for microstylets, the supernumerary hook was included here to emphasize its similarity in structure and function 29 to the hooks described above. The supernumerary hook was only found in the genus Epioblasma.
Exterior surface sculpturing - This refers to the fine structure of the exterior surface of the glochidial valve
(viewed between 10,000 to 20,000 x). Exterior surfaces were rough, beaded, rosette, loose looped, ribbed loose looped, tight looped, or vermiculate.
Statistical Analysis
Univariate statistics were performed on glochidial valve measurements using NCSS 5.0 (Hintze, 1987). The mean and standard deviation was found for each morphometric character. The number of glochidia examined for each species and the range of measurements was also recorded. It should be noted that the number examined from character to character within a species varies with the number of micrographs taken of that character. One limitation of using an SEM is that the subject under view must be permanently fixed to a stub. This prevents the examination of all characters from each glochidium. Therefore, the description of the glochidium of a species will be a composite of the glochidia within one or more marsupia, from one or more female unionids, rather than a description of an individual glochidium.
Adductor muscle cross-sectional area and valve area were determined as described above. Regression analysis 30 (NCSS, 5.0) was performed to determine the relationship between the relative size of the glochidial adductor muscle and the degree of valve depression (dorso-ventral reduction). Relative adductor muscle size was determined by dividing the area of the adductor muscle by the area of the valve. An index of valve depression was calculated by dividing the length of a glochidium by its height.
Therefore, a glochidium with equal length and height would have a depression index of one, while a glochidium with unequal length and height would have an index value greater or less than one depending on whether the length or height was largest. Table 2 gives the ratios used in this analysis.
Multivariate statistics were performed on a binary data base derived from the character states described above.
Essentially, if a character state was present its value was one, and if absent its value was zero. Appendix D contains this data base.
Principal components analysis (PCA) was run using NCSS
5.0 software. The purpose of using a factor analysis, such as PCA, is to reduce the number of variables by summarizing the information content of many variables in a few. These weighted averages (factors) may then be plotted against each other to reveal group membership. Decisions on group membership can therefore be done without a priori assignment to groups. 31 Table 2. Relative adductor muscle cross-sectional area and index of valve depression from glochidia of the Unionidae. See Appendix B for specimen data (p. 298) and catalog numbers -
Species Catalog # L/H A/V L/H A/V
A. cyqnea OSUM:20911.2 1.04 18 1 . 0 0 14 1.05 18 1 . 0 0 11 1.05 13 1.05 12 1 . 0 0 17 A. berinqiana OSUM:3711.2 1 . 0 0 13 0.95 17 1 . 0 0 14 1 . 0 0 15 1 . 0 0 12 A. kennerlyi OSUM:52882.2 1 . 0 0 11 1.05 16 1.05 12 A. a* grandis OSUM:50838.14 1 . 1 1 12 0.96 12 1 . 0 0 14 1 . 0 0 14 1 . 0 0 17 A. a- corpulenta OSUM:38468.6 1 . 0 0 15 1.04 11 A. c . cataracta OSUM:19136.2 0.95 17 1 . 0 0 15 0.96 15 A. doliaris OSUM:26405 1 . 0 0 13 1 . 0 0 15 1.05 13 A. suborbiculata OSUM:13634 1.14 12 1 . 1 0 10 A. imbecillis OSUM:4432.3 1 . 0 0 14 0.97 10 UWZY:24971.1 0.97 13 1.06 12 A. califoriensis UMMZ:Uncataloged 1 . 0 0 19 1.14 23 1.13 23 A. ferussacianus OSUM:3379 1.08 12 S . ambigua UWZY:22658 0.93 10 0.93 9 UWZY:22662 0.87 8 UWZY:22672 0.93 11 S. u. undulatus OSUM:13880 1.25 22 1.24 21 OSUM:28082.2 1.29 24 S . u. tennesseensis O S U M :33 381.2 1.23 26 P . viridis OSUM:21506 1 . 2 0 30 P . compressa OSUM:16039.4 1.17 22 1.17 22 1.24 25 P. fabula OSUM:41308.3 1.08 59 A. marginata OSUM:53152 0.82 7 0 . 8 8 11 MAH:724.1 0. 91 8 0.83 11 0.92 11 L. costata MAH:585 0.87 9 0.94 12 MAH:882.1 0.95 11 INHS:2308 0.91 7 L. complanata INHS:1923 0.92 11 7 7 8 8 4 7 7 9 11 11 16 13 13 12 13 11 11 14 1.38 1.30 0.92 0.84 0. 58 0. 0.83 0.79 0.93 0.81 0.75 0.57 0.81 0.81 0 . 8 8 0.87 3 8 8 9 8 6 6 7 7 7 8 7 9 5 6 7 6 6 6 8 7 8 8 7 6 15 17 0.92 11 14 12 14 11 1358 0. 12 10 12 13 10 24 18 26 15 1.03 16 88 . . 0 . 8 6 1 . 0 0 1 . 0 0 1.30 1.33 0.91 L/H A/V L/H A/V 0.75 0.80 1.38 5 1.08 0.75 0 0.77 0. 90 0. 0.84 0.74 0.76 0.77 0.61 0.81 0. 56 0. 0.76 0.75 0.75 0.83 0.56 0.81 0.78 0.78 0.70 0.74 0.85 0.83 0.81 0 . 8 8 0. 90 0. 0.85 1 . 1 1 1.06 0.92 0.82 1 . 0 0 1 . 0 0 1.14
Catalog # OSUM:51107.4 OSUM:26318.11OSUM:45174.1 OSUM:21794 M A H : 654.2M A H : OSUM:19676.21OSUM:34335.112 OSUM:24337 UMMZ:Uncataloged MAH:586 OSUM:48067 MAH:842.1 OSUM:51282 OSUM:47696.3 OSUM:50233.7 OSUM:1983:58 UMMZ:Uncataloged MAH:659.2 M A H :658 OSUM:55466 UMMZ:Uncataloged OSUM:52335.4 UMMZ:Uncataloged UMMZ:Uncataloged UWZY:25024.1 UMMZ:Uncataloged OSUM:55828.4 M A H :897.2 MAH:845 OSUM:55976 OSUM:25467 O S U M -.34764.7 MAH:897.1 OSUM:20380.91 MAH:588.2 MAH:700.1 OSUM:27506.2 OSUM:19032.2
acksoniana brevidens . . boykiniana • • c . cylindrica p. . pustulosa . . nervosa . . verrucosa p. . plicata . ebena . . fasciolaris . . aberti . . pectorosa . subrotunda . . unicolor * * 1. carinata * olivaria . i * alatus * Purpuratus . conradicus . . retusa . . r . radiata * * e* ellipsiformis . . fragilis . . fasciola * A* * teres £. * luteola . . vibex . . othcaloogensis . metastriata. . . altilis * triguetra * * ventricosa * * A* i r i s Species Table 2. Continued 2l£IH I0(0«IM fc|0| <
Species Catalog # L/H A/V L/HA/V
E. lenior O S U M : 15 5 8 4 . 4 1.00 18 E. capsaeformis OSUM:3964.5 1.13 18 OSUM:42007 1.07 17 1.07 14 OSUM:43166 1 . 0 0 14 1.03 14 E. walkeri OSUM:15595.51 1 . 1 0 22 1.13 18 1.14 21 1 . 1 0 23 E. t. rangiana MAH:632.1 1.00 20
L/H = Length / Height A/V = cross-sectional area of adductor muscle / area of glochidial valve (expressed as % valve area) CHAPTER III
THE GLOCHIDIA OF THE UNIONIDAE
Glochidial Orientation
It might seem inappropriate to consider the orientation of an animal that has no means of self propulsion. Although glochidia rapidly and repeatedly open and close their valves, they have never been observed to swim like members of the marine family Fectinidae, nor do they have a foot with which to plow through their environment. Nonetheless, in order to describe the glochidial shell, to standardize the presentation of micrographs, and because a successfully transformed glochidium becomes a juvenile with defined directionality, the orientation of the glochidial shell was examined.
The use of the terms of directionality have been applied differently by the various authors working with glochidia (Hoggarth, 1987). Rather than to repeat the review of the problems associated with glochidial orientation, the reader is referred to the aforementioned article. The result of this study, however, was that when the outline of the glochidial shell was compared to the known orientation of the juvenile shell, a common glochidial 34 35 Dorsal c B A
Posterior Anterior
E D Ventral
Figure 9. Subtriangular glochidium of the Anodontinae demonstrating the directionality of a glochidium. AM = adductor muscle. orientation was found. The long side of the glochidial shell (margin AE, Fig. 9) was found to correspond to the anterior margin of the juvenile, and the short side (margin
CE, Fig. 9) corresponded to the posterior margin of the juvenile. The hinge (margin AC, Fig. 9) of the glochidial shell not surprisingly corresponded to the hinge margin
(dorsal margin) of the juvenile and point E (Fig. 9) was, therefore, ventral.
Figure 9 demonstrates the orientation of the anodontine glochidium and identifies the adductor muscle as anterior.
Not pictured here, but also used to orient a micrograph was the posterior position of the central ligament. Care was taken to orient micrographs, such as external and internal valve views, and micrographs of the hinge, so that they 36 would correspond to the orientation figured above; the
dorsal margin will be toward the top of the page, ventral
will be down, anterior will be toward the right hand margin
of the page and posterior will be left.
Glochidial Descriptions
Morphometric data will be presented in the following
format: Character mean ± standard deviation (number measured), range. The number of micrographs measured for any one character varied with the number of micrographs that accurately displayed the character. Micrographs of tilted specimens were not measured.
Family Unionidae (Fleming, 1828) Ortmann, 1911
Subfamily Unioninae (Fleming, 1828) Morrison, 1955. Type genus Unio Philipsson, 1788. Type species Mya pictorum
Linnaeus, 1758.
The glochidium of Unio has been described as subtriangular with a ventral hook (Ortmann, 1912). other than its smaller size, this glochidium resembles that of
Anodonta (Giusti, 1973). Ortmann (1918), however, reported the absence of a hook in Unio caffer, but Heard and Guckert
(1970) suggested that this was the result of examining immature specimens. They noted that Giusti (1973) demonstrated hooks in Unio elonqatulus glaucinus and that 37 McMichael and Hiscock (1958) found hooks on mature glochidia of Velesunio ambiquus even though the species was earlier described as having hookless glochidia (Hiscock, 1951).
The adults of Unio have oval to elongate elliptical shells that lack sculpturing except at the umbo where double-looped (B-shaped) or zig-zag (chevron-shaped) ridges may be found. The marsupial demibranchs are restricted to the outer gills, and these become pad-like when charged with young. Septa within the marsupia run parallel to the gill filaments and form water tubes.
Ortmann (1912) and Heard and Guckert (1970) placed this genus near the North American genus Fleurobema (Ambleminae) on the basis of similar shell morphology and anatomy.
However, Ortmann (1912) recognized the similarity between the glochidia of the Unioninae and the Anodontinae and suggested that the former gave rise to the latter. Morrison
(1955) agreed with Ortmann's conclusion regarding the origin of the Anodontinae but he chose to stress developmental characters (the similarity in glochidia) over adult characters and therefore placed the subfamily Unioninae near the Anodontinae. Morrison (1955) also cited tripartite water tubes for the Unioninae and used this character to ally these two subfamilies. However this may be in error since the division of the water tubes into three chambers has not been demonstrated for the Unioninae. 38 Unio elongatulus glaucinus Porro, 1838
Glochidium subtriangular (Figs. 10a, 10b) with a length
of 227 ± 6.45um (4); 218-232um, and a height of 216 ± 4.08um
(4); 210-218um, Anterior and posterior margins are arcuate,
meeting at the base of the hook to form a broadly rounded
ventral terminus. The valve outline is only slightly
asymmetric with the anterior margin slightly more produced
than the posterior margin. The exterior surface of the
valve is malleated (large dimple-like depressions) and pitted (smaller depression generally within malleated valve
surface), except along the valve boarder where the shell is
smooth. The fine sculpture of the exterior valve surface is beaded (Fig. lOe).
The midpoint of the central ligament is located about
40% from posterior to anterior and the length of the central
ligament is 56 ± 1.73um (3); 55-58um (Figs. 10b, lOf). The posterior ligament is 42 ± 1.53um (3); 41-44um in length, and the anterior ligament is 72 ± 3.60um (3); 68-75um in length. The dorsal margin is straight with an average length of 171 + 4.36um (4); 164-175um.
A styliform hook extends from the ventral terminus of each valve as a broad triangular plate (Figs. 10b, 10c, lOd) . The hook gradually and uniformly tapers to a broad point distally and is located about 50% from both lateral margins. Most of the surface of the hook is covered by microstylets (about 35) and micropoints. A majority of the 39 microstylets are bluntly pointed, however, a few of the more
proximal microstylets are multifaceted and sharply pointed.
Micropoints extend from the lateral and proximal margins of
the styliform hook and cover most of its lateral surfaces,
except within a narrow band distally.
Harms (1908, 1909) and Haas (1910) gave length and
height measurements of 290um for the glochidium of U. pictorum. Giusti (1973) noted that the glochidium of U. e. glaucinus is smaller than that of Anodonta, but gave no measurements for the size of the glochidium. The glochidia described here are much smaller than Anodonta and smaller than the measurements given for U. pictorum. An examination of the glochidia of the myriad nominal species of Unio might provide some characters, such as relative glochidial size, that could be used to help define the species of Unio.
Anodontinae (Rafinesque, 1820) Morrison, 1955. Type genus
Anodonta Lamarck, 1799. Type species Mytilus cyqneus
Linnaeus, 1758.
Clarke (1981a) divided this subfamily into two tribes;
Tribe Anodontini (Anodonta, Anodontoides and Strophitus) and
Tribe Alasmidontini (Alasmidonta. Lasmiqona, Feqias.
Arcidens, and Simpsonaias). Gordon (1981) separated the genus Strophitus from the Anodontini citing its unusual arrangement of glochidia in the marsupium of the female as sufficient reason to place this genus in a tribe by itself. 40 An examination of the glochidia of the species of the
Anodontinae suggest a slightly different phylogenetic
arrangement than that proposed by Clarke and does not
support Gordon's separation of Strophitus. The sequence of
glochidial descriptions below demonstrates a continuum
between the genus Anodonta and Lasmiqona. with just a single
species, Simpsonaias ambigua, separated from the North
American Anodontinae. On the basis of glochidial characters
S. ambigua appears to be very close to Unio.
Anodonta Lamarck, 1799. Type species Mytilus cygneus
The glochidium of Anodonta is large, sturdy and
generally subtriangular in shape. The anterior margin of
the valve is generally much more broadly rounded than the
posterior margin and a styliform hook is present at the
ventral terminus of each valve. Lillie (1895) described the
glochidium of Anodonta as, "quite thick, strong and brittle,
and pierced by numerous fine pores."
The adults of Anodonta are characterized by the
complete absence of hinge dentition, thin elliptical to
subrotund shells and double-looped umbo sculpture. In
Anodonta, as in all members of the Anodontinae, we find an unusual compartmentslization of the gravid marsupium. When charged with young, the demibranchs divide longitudinally
into three compartments. The middle compartment contains the developing larvae while the inner and outer compartments 41 remain open and probably facilitate the exchange of gasses within the marsupium.
Anodonta cygnea (Linnaeus, 17 58)
Glochidium subtriangular (Figs. 11a, lib) with a length of 351 + 4.33um (9); 345-358um, and a height of 351 ± 4.41um
(9); 344-357um. The anterior margin is rounded with its maximum inflation at approximately 50-60% from the dorsal margin. The posterior margin gently curves throughout its length and the valve outline is only moderately asymmetric, with the anterior margin more produced than the posterior margin, and the narrowly pointed ventral terminus located about 40% from posterior to anterior. The exterior surface of the valve is malleated and pitted except in a narrow band along the lateral margins. Pit density is reduced in the area of the adductor muscle scar (Figs. lib, 11c), and loose looped sculpturing is present on the exterior surface of the valves (Fig. lie).
The central ligament is 84 ± 3.27um (5); 79-88um in length and centered about 41% from posterior to anterior
(Figs. lib, Ilf). The posterior ligament is 7 3 ± 5.22um
(5); 68-79um in length, and the anterior ligament is 115 ±
2.12um (5); 112-118um long. The hinge is straight, 274 ±
3.35um (9); 268-279um in length.
A styliform hook arises from the ventral terminus as a broad triangular plate (Figs. lib, lid). The lateral 42 margins of the hook are not straight as in U. e. glaucinus,
but concave and rapidly narrowed producing a sharp point.
Microstylets are lanceolate, sharply pointed, arranged in
four rows near the ventral terminus and reduced to a single
row distally. Micropoints are numerous, covering the
ventral terminus and the lateral surfaces of the hook,
except within a narrow band along the distal edge.
This glochidium can be distinguished from that of Unio by its shape, hook structure, exterior valve sculpturing and size. Length and height measurements of 3 50um have been given for the glochidium of A. cyqnea by Harms (1909), Haas
(1910) and Ortmann (1912). This glochidium has been figured by Ortmann (1912, pi. 19, fig. 2) and Wood (1974, figs. 3, 4).
Anodonta anatina (Linnaeus, 1758)
Glochidium subtriangular, moderately asymmetric (Figs.
12a, 12b) with a length of 357 ± 3.91um (7); 350-361um, and a height of 354 ± 4.46um (7); 348-361um. The anterior margin is broadly curved near the dorsal margin and more moderately curved ventrally. The curvature of the posterior margin is gentle and even throughout its length. Exterior malleations and pits occur except along the valve margin and the interior surface is uniformly pitted, without a noticeable adductor muscle scar. The sculpturing of the exterior valve is a modification of loose looped valve 43 sculpturing. Here the raised loops are restricted to bands
that run parallel to the dorso-ventral axis of the valve,
and the exterior surface between the bands is smooth. This
type of exterior valve ornamentation is referred to here as
ribbed loose looped sculpturing (Fig. 12c). A larval thread
was observed in this glochidium (Figs. 12b, 12e, 12f).
The central ligament is 91 ± 5.00um (3); 86-96um in
length and is centered about 4 3% from posterior to anterior
(Fig. 12b). The posterior ligament is 63 ± 5. Slum (3);
57-68um long, and the anterior ligament is 118 + 5.86um (3);
114-125um long. The hinge is straight with a length of 269
± 6.37um (7); 260-278um.
The structure of the styliform hook is very much like that of A. cygnea (Fig 12d) . The lateral margins are biconcave to a sharp distal point. Microstylets (about 15) are lanceolate (Fig. 12g), sharply pointed, and reduced to a single row distally. Micropoints are numerous, covering the ventral terminus and lateral surface of the hook, except along its distal edge, and the hook is located about 40% from the posterior margin.
This glochidium is distinguished from that of A. cygnea by its unique exterior valve sculpturing. Giusti (1973) and
Giusti et al. (1975) were the first to demonstrate this unusual sculpturing. They refer to their species as A. cygnea (Anodonta piscinalis). Anodonta piscinalis was placed in the synonymy of A. cygnea by Simpson (1900, 1914) 44 and Ortmann (1912). Anodonta anatina has also been
synonymized with A. cygnea by Ortmann (1912) although it was treated as a variant of A. cygnea by Simpson (1900, 1914).
Furthermore, Ortmann (1912) recognized a second species of
Anodonta in Europe j[A. complanata) and this species was placed in the synonymy of A. anatina by Simpson (1914).
There is little question that I examined two species based on glochidial characters. These species have many characters in common, but their exterior valve sculpturing is sufficiently different to separate them. At my request,
Dr. Stansbery reexamined the adult shells of the females that supplied the glochidia for this comparison, and he came to the same conclusion based on adult shell characters.
Glochidia of A. anatina have been figured by Flemming (1875, pi. 3, fig. 11), Schierholz (1889, pi. 2, fig. 29), Ortmann
(1912, pi. 19, fig. 3, as A. complanata) , Giusti (1973, figs. 13-25, as A. cygnea) and Guisti et al. (1975, figs.
10-21, as A. cygnea).
Anodonta beringiana Middendorff, 1851
Glochidium subtriangular, moderately asymmetric (Figs.
13a, 13b) with a length of 289 ± 2.28um (5); 286-292um, and a height of 290 ± 3.42um (5); 284-293um. Anterior and posterior margins are about equal, more or less gently curved, however the anterior margin is slightly more produced, especially in the dorsal half of the valve. The 45 point of maximum anterior inflation occurs at about 50% from
dorsal to ventral and the ventral terminus is narrowly
pointed and located about 41% from the posterior margin
(Figs. 13a, 13b, 13c). The exterior surface of the valve is
malleated and pitted. Pits are uniformly distributed except
along the valve margin where they are absent, and loose
looped sculpture covers the exterior surface of the valve.
As with other members of this genus, the glochidium of A.
beringiana has a larval thread (Figs. 13a, 13c).
The hinge is straight with a length of 211 + 2.35um
(5); 209-214um. The hinge of a single specimen gave the
following ligament lengths: posterior ligament, 3 4um;
central ligament, 58um; and anterior ligament, 118um. The
midpoint of the central ligament is far posterior at 31%
from posterior to anterior.
A styliform hook arises as a broad biconcave triangular
plate (Figs. 13b, 13d, 13e, 13f). Microstylets are stout,
multifaceted and few in number (about 15). Micropoints are
limited to the ventral rim of the valve, along the lateral
edges of the microstylets and for a short distance on the
lateral surfaces of the hook. The unsculptured margin,
along the distal edge of hook, is wide.
This species has been allied, on the basis of adult
shell morphology, to A. cygnea by Simpson (1914). The shape of this glochidium also allies A. beringiana with A. cygnea, however the glochidium of the former species can be 46 distinguished from that of the latter by its smaller overall
size and hook structure. Inaba (1941) gave 296um for the
length and height of the glochidia of A. beringiana. and
Cope (1959) reported length and height measurement of 275um x 300um.
Anodonta kennerlyi Lea, 1860
Glochidium subtriangular, moderately asymmetric (Figs.
14a, 14b) with a length of 352 ± 2.08um (3); 350-354um, and a height of 344 ± 5.13um (3); 340-350um. The anterior margin is rounded, tapering to meet a slightly curved posterior margin at the ventral terminus. The ventral terminus is narrowly pointed and about 40% from posterior to anterior. Malleations and pits are uniformly distributed in the valve except along the valve margin where dorsally converging longitudinal ridges are found (Fig. 14c).
Exterior valve sculpturing is intermediate between beaded and loose looped (Fig. 14e) and resembles short lengths of strung beads closely packed upon the surface of the valve.
The hinge is straight and 259 + 7.31um (6 ); 250-267um in length (Figs. 14b, 14f). The length of the posterior ligament is 60 ± 3.25um (6 ); 55-65um, the central ligament is 87 ± 2.07um (6 ); 84-89um long, and the anterior ligament is 109 ± 2.94um (6 ); 106-114um long. The midpoint of the central ligament is about 40% from the posterior margin. 47 The styliform hook is sharply pointed and has fewer than 20 microstylets (Fig. 14b, 14d). The microstylets are lanceolate and sharply pointed. They are arranged in four proximal rows and are reduced to a single row distally. Two to three microstylets and as many as seven micropoints form a cluster near the tip of the hook. Additional micropoints are found on the lateral surfaces of the hook, along the lateral borders of the microstylets and on the ventral terminus. This leaves a rather narrow unsculptured distal hook e d g e .
This species is also allied to A. cygnea by Simpson
(1914) due to similarity in adult shell morphology. Again, the shape of this glochidium is similar to that of A. cygnea, however this species can be distinguished from the former by its exterior surface sculpturing and the cluster of microstylets and micropoints near the point of the hook.
This aspect of the styliform hook resembles that found in A.
grandis and related species east of the Rocky Mountains.
Clarke (1967) examined the shells of this species and concluded it is related to both A. cygnea and A. cataracta.
Anodonta grandis grandis Say, 1829
Glochidium subtriangular and asymmetric (Figs. 15a,
15b) with a length of 356 ± 5.56um (7); 350-365um, and a height of 355 ± 3.10um (7); 350-360um. The dorsal margin is straight, the posterior margin gently curves throughout its 48 length, and the anterior margin is broadly curved to its point of maximum inflation at about 70% from dorsal to ventral. The ventral terminus is broadly rounded and located about 40% from posterior to anterior and the surface of the valve is malleated and pitted except along its margin where dorsally converging longitudinal ridges are found
(Fig. 15c). An adductor muscle scar is not evident (Figs.
15b, 15e) and coarse loose looped exterior valve sculpturing covers the surface of the valve (Fig. 15f).
The hinge is straight and 253 ± 3.20um (7); 250-258um in length (Fig. 15b). The central ligament is 92 ± 2.08um
(3); 90-94um long, the posterior ligament is 57 ± 4.04um
(3); 54-62um long, and the anterior ligament is 107 ± 3.Slum
(3); 104-lllum long. The midpoint of the central ligament is between 41-42% from the posterior margin.
The hook is styliform with about 20 microstylets. The microstylets are arranged in four proximal rows, and are reduced to a single row distally (Fig. 15b, 15d). Five to six sharply pointed microstylets form a cluster near the tip of the hook. Micropoints are few in number and are found only along the ventral rim of the valve and along the boarders of the microstylets. The unsculptured distal hook margin is very wide.
The glochidium of A. 3 . corpulenta is nearly identical to that of A. 2 * grandis. Morphometries from A. g. corpulenta are: length, 349 ± 5.13um (3); 343-350um; height, 49 366 ± 3.54um (2); 363-368um; hinge length, 266 ± 7.94 (3);
260-275um; and the hinge of a single specimen gave the
following ligament lengths: posterior ligament, 70um;
central ligament, 9 3um; anterior ligament length, lOOum.
Surber figures this glochidium {1912, fig. 4, 1913, fig. 1)
and gives (1912) length and height measurements of 350um.
Ortmann (1912) gave 360um x 370um for length and height
of the glochidium of A. g. grand is and Tucker (1928)
reported the following ranges: length, 350-398um; height,
343-390um. However, Surber gave measurements of 410um x
420um. This extremely large range in size led Tucker (1928) to suggested that this was the result of examining the glochidia of a far ranging, variable species. Her material,
Ortmann's and mine came from small streams, while Surber's material probably came from the Mississippi River and probably represents the glochidia of A. g. giqantia. The glochidium of A. g. grandis is figured by Lea (1858, pi. 5, figs. 32, 33, 34, as A. lewisii. A. ovata and A. decora = A. g. grandis fide Ortmann, 1919) and Surber (1912, pi. 3, fig.
45). Lea's figures are slightly different from each other and none show the correct outline. Surber's figure demonstrates the asymmetry in this glochidium.
Anodonta cataracta cataracta Say, 1817
This glochidium is nearly identical with the glochidium of A. g. grandis. It is subtriangular and asymmetric (Figs. 50 16a, 16b). The dorsal margin is straight, the posterior
margin is gently and evenly curved and the anterior margin
is broadly curved to its maximum inflation at about 70% from
dorsal to ventral. The ventral terminus is broadly pointed
and about 43% from posterior to anterior. Malleations and
pits are uniformly distributed in the valve except along its
margin and the exterior surface of the valve is covered by
coarse loose looped sculpturing (Fig. 16d).
Morphometries from A. c. cataracta are: length, 376 ±
2.61um (5); 374-380um; height, 363 ± 7.40um (5); 351-370um;
hinge length, 284 ± 5.92um (5); 277-291um; posterior
ligament length, 73 ± 2.83um (2); 71-75um; central ligament
length, 100 ± 2.83um (2); 98-102um; anterior ligament
length, 116 ± 0.71um (2); 115-116um. The midpoint of the central ligament is about 42% from posterior to anterior
(Figs. 16b, 16c). The subspecies, A. c. marqinata had the following morphometries: length, 359 ± 1.41um (2);
358-360um; height, 367 ± 3.54um (2); 364-369um; and hinge length, 277 ± 0.71um (2); 276-277um. A single specimen gave the following ligament lengths: anterior ligament, 1 0 2 um; central ligament, llOum; and posterior ligament, 64um.
The hook of this species is styliform, as in A. grandis (Fig. 16e). Microstylets (about 20) are lanceolate, arranged in four rows near the ventral terminus, reduced to a singe row distally and clustered near the tip of the hook
(four to six per hook). Micropoints are limited to the 51 proximal half of the hook, except along the lateral margins
of the microstylets where they form a single row. As in A.
£■ grandis, the unsculptured distal hook margin is very w i d e .
Ortmann (1912) believed this species was the eastern
representative of the A. grandis complex. The similarities
between the glochidia of these two species support the view
of close relationship, however the glochidium of A.
cataracta can be distinguished from that of A, grandis by
its longer central ligament. The central ligaments of A. c.
cataracta and A. c. marginata are longer than any other
species of Anodonta. Rand and Wiles (1982) gave length and
height measurement of 382um x 383um, while Ortmann (1912)
reported 360um x 370um (identical to his figures for A. g.
grandis). This glochidium is figured by Lefevre and Curtis
(1910, fig. C, 1912, fig. 1C), Calloway and Turner (1979,
pi. 3, figs. 1, 3, 5, 7, 8 ) and Rand and Wiles (1982, figs.
1-4) .
Anodonta doliaris Lea, 186 3
The glochidium of this species is essentially identical
to that of A. g. grandis and A. c. cataracta. Its shape and hinge structure (Figs. 17a, 17b), exterior valve sculpture
(Fig. 17c) and hook structure (Fig. 17d) place it firmly with these species. What distinguishes the glochidium of this species is its unusually variable size. One glochidium 52 measured 317um x 317um x 240um (length x height x hinge length) (Fig. 17b), while another measured 405um x 368um x
3Q5um (Fig. 17a). Both glochidia were removed from the marsupium of a single female. With such a limited amount of material and with such great variability in size, it would not be appropriate to suggest limits, however the larger measurements seem out of range for glochidia in this group with the exception of A. g. qigantia.
Anodonta implicata Say, 1829
Glochidium lachrimiform with pronounced asymmetry
(Figs. 18a, 18b). The dorsal margin is relatively short and straight. The posterior margin is gently curved and the anterior margin is subrotund. Maximum inflation of the anterior margin occurs at about 50% from dorsal to ventral and a broadly rounded ventral terminus is located about 3 5% from posterior to anterior. The exterior valve surface is finely malleated and pitted except at the valve margin.
Pits are uniformly distributed in the malleated surface
(Fig. 18a, 18d) and the exterior valve sculpturing is intermediate between beaded and loose looped, similar to that of A. kennerlvi (Fig. 18f).
Morphometries from A. implicata are: length, 3 43 ±
0.71um (2); 342-343um; height, 348 ± 3.54um (2); 345-350um; hinge length, 163 ± 3.06um (3); 160-166um; posterior ligament, 38 ± 0.71um (2); 37-38um; central ligament, 76 ± 53 2.12um (2) 74-77um; anterior ligament, 48 ± 6.36um (2);
43-52um. The midpoint of the central ligament is about 46%
from the posterior boarder of the hinge (Fig. 18e).
The hook is styliform, broadly triangular and gradually
tapered to a blunt point (Fig. 18c). Microsculpture on the
hook gradually increases in size toward its center.
Microstylets are lanceolate and arranged in four rows near
the proximal boarder of the hook. Micropoints are numerous
and extend down the lateral surfaces of the hook to produce
a narrow unsculptured distal hook margin.
Johnson (1946) describes this glochidium as, "typical
of the genus Anodonta," even though his figure shows the
short hinge line and greatly inflated anterior margin, both
characters far from typical for this genus. Rand and Wiles
(1982, figs. 5-8) have also failed to recognize that this
species can be distinguished from all other glochidia simply by the tear-drop outline of the valve. This glochidium is
further distinguished by its hook structure and exterior valve sculpture. The glochidium of this species is figured by Johnson (1946, pi. 16,fig. 3) and Rand and Wiles (1982, figs. 5-8). Rand and Wiles give length and height measurements of 34Sum x 34Sum.
Anodonta suborbiculata Say, 1831
Glochidium subtriangular (Figs. 19a, 19b) with a length of 325 ± 2.08um (5); 323-328um, and a height of 323um ± 54 3.46um (5); 320-328um. The dorsal margin is straight and
234 ± 2.41um (5); 231-237um long. The posterior margin is
gently curved, and the anterior margin is broadly curved.
The point of maximum anterior inflation is about 50% from
dorsal to ventral and the ventral terminus is narrowly
pointed and located about 42% from posterior to anterior.
The exterior surface is malleated and pitted (Fig. 19e)
except along the edge of the valve (Fig. 19c) and the fine
structure of the exterior surface consists of fine
non-overlapping lines referred to here as vermiculate
sculpturing (Fig. 19f).
The central ligament is long and positioned about 45%
from posterior to anterior (Fig. 19b). Its length is 100 ±
1.71um (4); 98-102um long, while that of the posterior
ligament is 54 ± 1.83um (4); 52-56um long, and the anterior
ligament is 78 ± 2.99um (4); 74-81um long.
The hook is styliform with about 40 lanceolate
microstylets and many micropoints (Fig. 19d). The
unsculptured distal margin of the hook is narrow and the
hook is located about 45% from the posterior boarder.
This glochidium can be distinguished by its exterior
valve sculpturing and hook. It resembles A. cygnea in shape
but it has no other characters to tie it to this species.
Surber (1915) stated that in, '‘general outline [the
glochidium of A. suborbiculata closely resembles Anodonta grandis but may be distinguished by its smaller size". He 55 gave measurements of 32Sum x 3 20um for length and height.
However, the glochidia of these species are only
superficially similar and a close relationship between this
species and any other member of the genus is not supported by glochidial characters. The glochidium of A.
suborbiculata is figured by Surber [1915, pi. 1, fig. 1 ) and
Utterback (1915-1916, fig. 7).
Anodonta imbecillis Say, 1829
Glochidium subtriangular (Figs. 20a, 20b) with a length of 304 ± 6.41um (14); 291-313um, and a height of 300 ±
6 .Hum (14); 289-306um. The dorsal margin is straight and
246 ± 5.97um (11); 240-256um long. Anterior and posterior margins are slightly and evenly curved. The anterior margin is only slightly more produced than the posterior margin and the valve outline is only slightly asymmetric. The surface of the valve is weakly malleated and pitted except along the valve margin where the valve surface is smooth. The surface of the valve is covered with a uniform looped sculptured referred to here as tight looped sculpture (Fig. 20f).
The central ligament is 89 ± 3.50um (4); 85-93um long and centered about 42% from the posterior boarder of the hinge (Figs. 20b, 20e). The anterior ligament is 101 ±
3.79um (4); 95-103um in length, and the posterior ligament is 61 ± 1.50um (4); 60-63um long. 56 The hook is styliform and arises as a broad triangular plate from the ventral terminus (Figs. 20b, 20c).
Microstylets are lanceolate near the distal margin of the hook and multifaceted near the proximal boarder (Figs. 20c,
20d) . They are arranged in three to four rows near the ventral terminus but are reduced to a single row distally.
A cluster of microstylets and micropoints near the point of the hook may be present (Fig. 20c), however most of the micropoints cover the proximal half of the lateral surface of the hook, leaving a wide unsculptured distal margin. The ventral terminus is about 45% from posterior to anterior.
This glochidium can be distinguished from others in the genus by its exterior valve sculpture, its rather small size and its relatively long central ligament. It resembles A. suborbiculata in these last two characters but differs in valve sculpture and hook structure. The outline of this glochidium is like that of A. cygnea while the hook allies this species to A., grandis. Ortmann (1912) gave length and height measurements of 3 00um x 310um (for A. imbecillis) and
290um x 300um (for A. henrvana = A. imbecillis fide Johnson,
1970). Surber (1912) gave 310um x 290um and Tucker (1927) reported 290um x 300um. This glochidium is figured by Lea
(1858, pi. 5, fig. 36), Ortmann (1911, pi. 89, fig. 13),
Surber (1912, pi. 1, fig. 2) and Tucker (1927, pi. 10, figs.
1 , 2 ). 57 Anodontoides Simpson, 1898. Type species Anodonta
ferussaciana
The glochidium of Anodontoides is essentially like that
of Anodonta. It is subtriangular with a ventral hook
supporting microstylets and micropoints. The anatomy of the
adult is essentially that of Anodonta as well. Ortmann
(1912) stated that this species is, "an Anodonta with
concentric beak sculpture."
The shell of the adult is subelliptical, inflated and
thin. It lacks sculpture except at the umbo where delicate
concentric ridges are found. Hinge teeth are absent but
there may be a thickening of the shell in the hinge region
similar to that found in Strophitus. The anatomy of A.
ferussacianus is essentially that of Anodonta.
Anodontoides ferussacianus (Lea, 1834)
Glochidium subtriangular, only slightly asymmetric
(Figs. 21a, 21b). The dorsal margin is straight, while the posterior and anterior margins are about equally curved to a
bluntly rounded ventral terminus. This glochidium is 32 3 ±
3.20um (7); 319-326um long, and 324 ± 2.64um (7); 320-327um
high. Its hinge is 234 ± 2.93um (7); 231-238um in length.
The exterior surface is malleated and pitted except along
the lateral margins and within a circular dorso-medial area.
(Figs. 21a, 21c at arrows). This is the oldest part of the
shell and therefore will be referred to here as the umbo. 58 The surface of the valve is covered by loose looped sculpturing (Fig. 21e).
The central ligament is 91 ± 2.31um (3); 88-92um long and centered about 42% from posterior to anterior (Fig.
21b). The anterior ligament is 86 ± 3.06um (3); 83-89um in length, and the posterior ligament is 59 ± 3.06um (3);
56-62um long. The interior central portion of this ligament can be seen in Figure 21b while the exterior portions of this ligament (the posterior and anterior ligaments) are demonstrated in Figure 21c.
The hook is styliform with two rows of microstylets extending distally for at least three quarters of its length
(Figs. 21b, 21d). At the distal end of the double row of microstylets a cluster of microstylets and micropoints, like that in Anodonta. occurs. Micropoints are also located on the ventral rim of the valve and on the proximal surfaces of the hook leaving a wide unsculptured distal hook margin.
The position of the hook is 50% from posterior and anterior marg i n s .
This glochidium is very similar to glochidia of
Anodonta, however it can be distinguished from these by its double row of microstylets distally and its symmetry. The hook of this glochidium resembles that of strophitus and
Fressodonta but the outline of its valve is essentially like that of Anodonta. Ortmann (1912) and Surber (1912) gave the following size range for the glochidium of A. ferussacianus; 59 32Q-330um x 320-330um. This glochidium is figured by Lea
{1858, pi. 5, fig. 35), Ortmann (1911, pi. 89, fig. 12) and
Surber (1912, pi. 13, fig. 43). Lea figured this glochidium without hooks but ortmann (1919) suggests that Lea’s specimens were immature.
Simpsonaias Frierson, 1914. Type species Alasmidonta ambigua
The glochidium of S. ambigua has only rarely been available for description. Lea (1858) described the glochidium of Margaritana hildrethiana (= S. ambigua fide
Simpson, 1900) as subrotund with a straight or slightly incurved dorsal line and lacking hooks. He suggested, however that hooks might be present in more mature specimens. Howard (1915, 1951) described the glochidium as triangular with well developed hooks and Clarke (1985) added that the glochidium is slightly asymmetric with malleated surfaces. Clarke*s description, however, is of Howard's figure rather than of glochidia he examined.
The shell of the adult is small (to 5cm long), elongate
-oval, thin and rather delicate. It is not sculptured, except at the umbo where v-shaped ridges are found, and hinge teeth are incomplete; pseudocardinal teeth are usually present, lateral teeth are absent. Clark (1985) suggested that the V-shaped ridges at the umbo correspond to the central portion of double-looped sculpture. The soft parts are anodontine in structure with tripartite outer 60 demibranchs becoming pad-like when filled with young.
Clarke (1985) stated that the phylogenetic position of the
species is obscure and that it does not appear to have close
affinities to any other North American species. I have
placed the species here because of its primitive glochidial
characters. This species probably represent an early
off-shoot from the Unio - Anodonta line.
Simpsonaias ambigua (Say, 1825)
Glochidium ovate subtriangular, slightly asymmetric
(Figs. 22a, 22b) with a length of 255 ± 3.39um (6 );
250-258um, and a height of 261 ± 3.43um (6 ); 256-265um. The
dorsal margin is straight and 168 ± 2.22um (7); 164-170um in
length. The posterior margin is gently and evenly curved
and the anterior margin is slightly more rounded than the
posterior margin. The point of maximum anterior inflation
is near 60% from dorsal to ventral and the ventral terminus
is bluntly rounded and about 4 5% from posterior to anterior.
The hinge of the glochidium appears to be curved when looked
down on from above (Fig. 22a). However, this is merely a
result of a deep umbo cavity (Fig. 22c). Nonetheless, the
curvature would appear to be outward rather than inward as
stated by Lea (1858). The exterior surface of the valve is
finely malleated and uniformly pitted except along the valve margin and at the umbo, where the surface is smooth. At the
center of the umbo there is a single large depression (Fig. 61 22a). The fine structure of the exterior surface of the
valve is beaded (Fig. 22e).
The central ligament is 58 ± 4. Slum (3); 54-63um long,
and centered about 45% from posterior to anterior. The
posterior ligament is 48 ± 2.31um (3); 45-49um long, and the
anterior ligament is 63 ± 2.00um (3); 61-65um long (Figs.
22b, 22f).
The glochidial hook is styliform, like that of U. e.
glaucinus and A. implicata (Figs. 22b, 22d). It arises as a broad biconcave triangular plate from the ventral terminus and tapers to a sharp point. Micropoints grade into the more centrally located microstylets and both the micropoints and microstylets are lanceolate. The more proximal microstylets, however are multifaceted and sharply pointed and arranged four to five abreast. Micropoints are numerous on the ventral terminus and lateral surfaces of the hook leaving a narrow unsculptured distal hook margin.
This glochidium can be distinguished by its shape, size, hook structure and exterior valve sculpturing. Its outline resembles that of the genus Anodonta in that both have gently and evenly curved posterior margins, more broadly rounded anterior margins and maximum anterior inflation between 50-70% from dorsal to ventral. However in regards to valve symmetry, size, hook structure, hinge structure and exterior valve sculpture this glochidium is reminiscent of Unio. The glochidium of S. ambigua is 62 figured by Lea (1858, pi. 5, fig. 31), and Howard (1951,
figs, 4a, 4b). Lea's figure is much too round and lacks
hooks. Howard's figures show the outline of this glochidium
correctly but the hook lacks microstylets in his drawing.
Howard's figures are reprinted in Clarke (1985, fig. 20d).
Strophitus Rafinesque, 1820. Type species Anodonta undulata
The glochidium of Strophitus is morphologically
depressed, pyriform and possess a styliform hook at the
ventral terminus of each valve. Lea (1858) described the
glochidia of Strophitus edentula (= S. undulatus fide
Johnson, 1970) and S. undulata as subtriangular, with a long
straight dorsal margin, inflated side margins (Lea
erroneously viewed all glochidia as symmetrical about the
dorso-ventral axis) and a large hook with four rows of
"granules" proximally, reduced to two rows distally. Other
than shape. Lea's description is surprisingly accurate.
The adult shell is subelliptical to subovate, thin to moderately solid and unsculptured except at the umbo where heavy concentric ridges are found. These ridges are very much like those in Anodonto ides except here they are generally much stronger. Pseudocardinal teeth are represented by a mere swelling in the hinge and lateral teeth are absent. The marsupium is formed by the outer gills which become distended and pad-like when charged.
Unique to this genus, is the cross-wise subdivision of the 63 larvae into solid packets called placentae. The placentae
are discharged entire by the female and may facilitate the
parasitic encounter by attracting the host or by positioning
the glochidium for attachment. It has also been suggested
that the glochidium may use the gelatin-like matrix of the
placenta as a nutrient source when it transforms without
going through the parasite stage (Lefevre and Curtis, 1912).
Strophitus undulatus undulatus (Say, 1817)
Glochidium depressed pyriform, asymmetric (Figs. 23a,
23b) with a length of 363 ± 5.20um (3); 360-369um, and a
height of 295 + 5.29um (3); 289-299um. The dorsal margin is
straight and 278 ± 3.78um (6); 271-281um in length. The posterior margin is broadly arcuate while the anterior margin is almost round, meeting the posterior margin at a
slightly rounded and ventrally produced, nipple-like, ventral terminus. The location of the ventral terminus is about 44% from the posterior margin and the exterior valve surface is malleated. Numerous pits are located uniformly throughout the valve except along the valve margin and at the umbo and coarse loose looped sculpturing covers the exterior surface of the valves (Fig. 2 3e).
The central ligament is located about 44% from the posterior margin and is 95 ± 6.55um (4); 87-103um in length.
The posterior ligament is 74 + 3.30um (4); 70-78um long, and the anterior ligament is 107 ± 4.08um (4); 101-llQum long. 64 The surface of the styliform hook is covered with about
30 microstylets and numerous micropoints (Figs. 2 3b, 2 3c,
23d). The proximal microstylets are bluntly pointed and the
distal microstylets are multifaceted and sharply pointed
(Fig. 23f). Two rows of microstylets extend distally and a
few microstylets and micropoints form a cluster near the
sharply pointed terminus of the hook. The unsculptured
distal hook margin is narrow.
The glochidium of S. u. tennesseensis is identical to
that described above. Morphometries for one glochidium are:
length, 346um; height, 298um; hinge length, 268um; central
ligament length, 94um; posterior ligament length, 78um;
anterior ligament length, 9Sum.
The glochidium of S. u. undulatus is unlike any so far
examined. Its shape, hook structure and coarse looped
sculpture will distinguish it from most other species. This glochidium is similar in most regards to that of Strophitus
subvexus, but it can be distinguished from this species by
its far less rotund shape. Glochidia of this species are figured by Lea (1858, pi. 5, fig. 37, as S. edentula , pi.
5, fig. 38, as S. undulatus) and Surber (1912, pi. 1, fig.
3, as S. edentula). Surber gave length and height measurements of 3 50um x 285um, and Ortmann (1912) gave 360um x 300um. 65 Strophitus subvexus (Conrad, 183 4)
Glochidium depressed pyriform, asymmetric (Figs. 24a,
24b, 24c) with a length of 354 + 5.Slum (3); 348-359um, and a height of 290 ± 2.08um (3); 288-292um. The dorsal margin is straight and 274 ± 2.50um (4); 271-277um in length. The posterior margin is broadly curved and the anterior margin is rounded. The side margins meet at a narrowly rounded, nipple-like ventral terminus which is located about 50% from posterior and anterior margins. The surface of the valve is coarsely malleated and uniformly pitted except along the valve margin and at the umbo (Figs. 24b, 24c) and coarse loose looped sculpturing covers the exterior surface of the valves (Fig. 24e).
The central ligament is about 84um in length and centered about 40% from posterior to anterior (Figs. 24b,
24f). The posterior ligament is about 70um long, and the anterior ligament is about 12 3um long.
The hook is styliform and like that of S. undulatus
(Figs. 24b. 24d). Proximal microstylets are bluntly pointed while the distal microstylets are lanceolate, multifaceted and sharply pointed. Microstylets are arranged in a double row distally and form a cluster near the point of the hook.
Micropoints are numerous on the ventral valve rim and the lateral surfaces of the hook and leave a narrow unsculptured distal hook edge. 66 The glochidium of S. subvexus is like that of S. u. undulatus except the former has a rounder outline and a more centrally positioned ventral terminus. The near symmetrical outline of this glochidium is overemphasized slightly by Lea
(1874, pi. 21, fig. 15, as Margaritana spillmanii = S. subvexus fide Johnson, 1967) but his figure correctly shows the broadly curving margins of this glochidium.
Pressodonta Simpson, 1900. Type species Unio viridis
Simpson (1900) and Clarke (1985) use Pressodonta as a subgenus of Alasmidonta. But the glochidium of Pressodonta sensu stricto is not at all like that of Alasmidonta undulata, the type of the genus. A reexamination of adult characters also reveals more dissimilarity between these two taxa than similarity. In fact, glochidial and adult characters ally the members of the subgenus Pressodonta with two subgenera of Lasmigona (ie. Platvnaias and Alasminota).
Therefore Pressodonta, the earliest available name, is used to unite these subgenera.
The glochidium of Pressodonta is depressed pyriform, very much like that of Strophitus. Its length is much greater than its height and the outline of the valve is moderately asymmetric. The hook is characterized by relatively few microstylets that form a double row distally and the exterior surface of the valve is covered with a form of looped sculpture. 67 The shell of the adult is small to medium sized. It
lacks sculpture, except at the umbo where double-looped or
concentric initial ridges becoming more and more inturned
centrally to approach double-looped sculpture may be found.
Pseudocardinal teeth are present; one or two in the right
valve and two in the left valve, seldom only one in the left
valve. Lateral teeth are generally present; sometimes
reduced, reversed in two species 1JP. heterodon and P.
compressa). but usually of the normal arrangement (one in
the right valve and two in the left). The marsupial
demibranchs are anodontine, with the middle compartment
containing the young. The developing young are often
surrounded by a placental mass while in the marsupium, but
they are not released in placentae as in Strophitus. The
inner lamella of the inner demibranchs are generally free
from the visceral mass, but the lamella may be attached
anteriorly for about one third its length.
Pressodonta (Pressodonta) viridis (Rafinesque, 1820)
Glochidium depressed pyriform, only slightly asymmetric
(Figs. 25a, 25b) with a length of 307 + 7.59um (7);
300-319um, and a height of 250 ± 4.35um (7); 245-258um. The dorsal margin is straight and 250 ± 3.93um (7); 245-258um long. The posterior margin is gently and evenly curved and the anterior margin is only slightly more produced than the posterior margin. The ventral terminus is roundly 68 pedecillate and about 45% from posterior to anterior. The
exterior surface of the valve is finely malleated and pitted
except along the valve margin (Fig. 2 5c) and at the umbo.
Pit density is reduced in the area of the adductor muscle
scar (Fig. 25f) and loose looped sculpture covers the exterior surface of the valve (Fig. 2 5e) .
The central ligament is 76 ± 4.16um (3); 73-81um in
length and its midpoint is about 42% from posterior to anterior. The posterior ligament is 67 ± 4.04um (3);
63-71um long, and the anterior ligament is 105 ± 4.93um (3);
100-109um in length.
The hook is styliform, broadly connected to the ventral terminus and covered with about 30 microstylets and numerous micropoints (Fig. 25b. 25d). Microstylets are lanceolate, arranged in three proximal rows and reduced to two distal rows. six to eight microstylets and micropoints form a cluster near the point of the hook and micropoints extend over the nipple-like ventral terminus beyond the edge of the ventral margin of the valve for a short distance on the lateral surfaces of the hook. The unsculptured distal edge of the hook is wide.
Clarke (1981a) described many of the glochidia of the
Alasmidontini using SEM, including this species. Our descriptions of this glochidium are almost identical except for the location of the hook. Actually, we agree here as well, but Clarke confused the anterior-posterior orientation €9 of the glochidium. He stated, "apices are located slightly
anterior of center (about 47%)." Actually the apices (=
ventral termini) are located about that distance from the
posterior margin.
Ortmann (1912) reported length and height measurements
of 300um x 250um and Surber (1912) gave 300um x 255um for
this glochidium. Clarke (1981a) gave the following ranges:
length 286-292um, height 232-235um, hinge length 205um. The
figure for hinge length is probably a typographical error
and should read 2 50um (approximate hinge length taken from
his Figs. 6b, 6c was 240-250um).
This glochidium is distinguished from that of
Strophitus by its finer exterior valve sculpture and its broadly connected hook. It is distinguished from
Pressodonta heterodon by its more symmetrical shape, and from the other members of this genus by the number of microstylets and the presence of a visible adductor muscle scar. This glochidium is figured by Lea (1858, pi. 5, fig.
30, as Margaritana deltoidea = P. viridis fide Simpson,
1900), Surber (1912, pi. 1, fig. 1, as Alasmidonta calceola
= P. viridis fide Clarke, 1981a), Ortmann (1912, pi. 19, fig. 4, as Alasmidonta minor = P. viridis fide Clarke,
1981a), Clarke (1981a, fig. 6) and Zale and Neves (1982a, fig. 1, as A. minor). 70 Pressodonta (Pressodonta) heterodon (Lea, 1829)
Glochidium depressed pyriform, symmetric when immature
(Fig. 26a) becoming asymmetric with the development of the
hook (Fig. 26b, 26c, 26d). This glochidium is 334 + 3.65um
(4); 330-338um long, and 265 ± 4.86um (4); 258-268um high.
The dorsal margin is straight and 261 + 5.94um (4);
253-266um in length. The posterior margin is slightly and
evenly curved, the anterior margin is more broadly curved, especially near the dorsal margin and its point of maximum
inflation lies between 40-50% from dorsal to ventral. The ventral terminus is curved and slightly produced outward.
The exterior valve surface is finely malleated and pitted except along its margins and at the umbo. Interior pitting is not uniform. The area of the adductor muscle scar is less densely pitted than the surrounding valve surface.
Loose looped sculpturing is found on the exterior surface of the valves (Fig. 26f).
The central ligament is centered about 42% from posterior to anterior and it is about 80um long. The posterior ligament is about 7 5um long and the anterior ligament is about llOum long. Only one micrograph accurately demonstrated the hinge of this glochidium.
A styliform hook extends dorsally from the ventral terminus (Figs. 26b, 26e) and it is covered with about 40 microstylets and many micropoints. Microstylets are arranged in four to six proximal rows and are reduced to two 71 rows distally. Micropoints extend over the edge of the
ventral terminus, along the ventral margin of the valve and,
for a short distance, upon the lateral surfaces of the hook.
The unsculptured distal hook margin is wide and the position
of the hook is about 42% form posterior to anterior.
Clarke's (1981a) and my descriptions of this glochidium
are not surprisingly very similar. We both examined
glochidia removed the same adult female. He reported
length, height and hinge length measurements of 325um x
255um x 267um. All of these are within the ranges found
during this study. This glochidium is very similar to that
of P. viridis but differs from this species in being more
inflated anteriorly and in having a less broadly attached
styliform hook. This glochidium is figured by Clarke
(1981a , fig. 9).
Pressodonta (Platynaias) compressa (Lea, 1829)
Glochidium depressed pyriform, longer than high, and
strongly asymmetric (Figs. 27a, 27b) with a length of 323 ±
4.39um (5); 317-327um, and a height of 286 ± 2. Slum (5);
283-288um. The dorsal margin is straight and 234 ± 3.36um
(5); 230-239um long. The posterior margin is strongly curved while the anterior margin is greatly inflated dorsally, becoming more gently curved ventrally. The posterior and anterior margins join at a gently rounded, nipple-like ventral terminus. The exterior surface of the 72 valve is coarsely malleated and pitted throughout except at
the umbo and at the margin of the valve (Fig. 27c) and loose
looped sculpturing covers its exterior surface (Fig. 27e).
The central ligament is 84 ± 0.71um (2); 83-84um in
length and centered about 46% from the posterior margin.
The posterior ligament is 68 ± 0.71um (2); 67-68um long and
the anterior ligament is 82 + 0.71um (2); 81-82um long.
The styliform hook is armed with about 25 stout
microstylets arrange in three proximal rows and two widely
off-set distal rows (Figs. 27b, 27c, 27d, 27f). Micropoints
extend over the edge of the valve at the ventral terminus
and along the valve margin. The distal half of the hook
lack micropoints producing a very wide unsculptured distal
hook margin. The ventral terminus is located about 45% from
posterior to anterior.
Surber (1912), Ortmann (1912), Tompa (1979) and Clarke
(1985) give length and height measurements for this
glochidium; 353um x 313um, 340um x 280um, 320um x 260um and
344um x 27Sum. This glochidium can be distinguished by its widely off-set double row of microstylets and its wide
unsculptured distal hook margin. Clarke (1985) described
the hook of this species as having a single distal row of microstylets, however his micrographs show only collapsed hooks that are very difficult to interpret. This glochidium is figured by Lea (1858, pi. 5, fig. 23, as Unio pressus =
P. compressa fide Simpson 1900), Ortmann (1911, pi. 89, fig. 73 10), Surber (1912, pi. 3, fig. 44) and Clarke (1985, fig.
13) .
Pressodonta (Platynaias) subviridis (Conrad, 183 5)
Glochidium depressed pyriform, longer than high, with a
strongly curved posterior margin and a broadly rounded
anterior margin (Figs. 28a, 28b). The point of maximum posterior inflation occurs about 3 0% from dorsal to ventral and the point of maximum anterior inflation occurs at about
40-50% from the dorsal margin. The dorsal margin is straight and 254 ± 6.82um (5); 245-264um in length. The length of the valve is 374 + 5.81um (5); 368-383um, and it is 312 ± 3.71um (5); 309-318um in height. The exterior valve surface is coarsely malleated and uniformly pitted except within a narrow marginal band. The ventral terminus is broadly rounded, not produced or nipple-like as in the other members of the genus, and locate about 40% from posterior to anterior. The exterior surface of the valve is covered by loose looped sculpture (Fig. 28c).
The central ligament is 88 ± l.OOum (3); 87-89um in length and centered about 40% from posterior to anterior
(Fig. 28b). The length of the posterior ligament is 63 ±
5. Slum (3); 57-68um, and the anterior ligament is 104 ±
3.61um (3); 100-107um long.
The hook is styliform (Figs. 28b, 28d) with about 25 microstylets and numerous micropoints. Microstylets are 74 lanceolate, about five to six abreast proximally and
arranged in a double row distally. The distal two rows are
off-set but not as widely as in P. compressa. Micropoints
are located on the ventral margin of the valve and upon the
lateral surfaces of the hook but they do not extend over the
edge of the valve at the ventral terminus (also see Clarke
1985, Fig. 16b). The unsculptured distal hook margin is w i d e .
This glochidium can be distinguished by its more broadly curved lateral margins and the absence of micropoints extending onto the valve at the ventral
terminus. Ortmann (1912) gave 360um x 300um for the length
and height of this glochidium and Clarke (1985) gave
35G-372um X 285-303um. This glochidium is figured by Lea
(1874, pi. 21, fig. 14, as Unio tappanianus = P. subviridis fide Ortmann and Walker, 1922) and Clarke (1985, fig. 16).
Lea's figure does not show the morphologically depression of this glochidium.
Pressodonta (Alasminota) holstonia (Lea, 1838)
Glochidium subtriangular, length and height about equal
(Figs. 29a, 29b). The length is 286 ± 3.65um (5);
281-291um, and the height is 282 ± 7.76um (5); 275-294um.
The dorsal margin is straight and 227 ± 5.32um (5);
221-235um long. The posterior margin is slightly and evenly curved with its point of maximum inflation about 20-30% from 75 the dorsal margin. The anterior margin is broadly curved
with a tendency to be incurved before the ventral terminus
and its maximum inflation occurs about 40-50% from dorsal to
ventral. The ventral terminus in narrowly rounded and
located about 40% from posterior to anterior. The exterior
surface is finely malleated and uniformly pitted except
along the valve margin and tight looped exterior valve
sculpturing covers the surface of the valve (Fig. 29c).
Clarke (1985) reported a central ligament length of
65um centered 3 5% from the anterior margin (actually the posterior margin). A central ligament length of 68 ± 7.07um
(2); 63-73um was found during this study with a midpoint about 38% form posterior to anterior. The posterior and anterior ligaments were 54 ± 2.12um (2); 52-55um, and 110 ±
0.71um (2); 109-llQum long, respectively.
The hook is styliform with about 20 microstylets and many micropoints (Fig. 29d). Micropoints are located on the ventral rim and lateral surfaces of the hook leaving a narrow unsculptured distal hook margin. Microstylets are lanceolate and arranged in a double off-set rows distally.
The shape of this glochidium resembles that of Anodonta except for the slightly incurved margins right before the ventral terminus. The hook structure also differs from that of Anodonta. These two characters, as well as the far posterior position of the hook, the broadly rounded anterior margin and looped exterior valve sculpture ally this 76 glochidium with the other members of the genus Pressodonta.
It is easily distinguished from these, however, by its shape
and the tightness of its looped sculpture.
Clarke (1985, fig. 2) suggests that this species is the
most primitive member of the tribe Alasmidontini, primarily
because the glochidium has a larval thread. A larval thread
is found in some members of the Margaritiferidae, the family
that is thought to have given rise to the Unionidae, and in
some member of the Unionidae (ie. some unionines, amblemines
and some members of the genus Anodonta). Clarke (1985) was
the first to report a larval thread in the Alasmidontini.
However, it is dangerous to base the systematic position of
a species on a primitive character (Hennig, 1966) since that
character has a tendency to appear randomly in a lineage.
In fact, a larval thread is reported here for the first time
in Alasmidonta undulata and Alasmidonta marqinata. both
considered by Clarke to be derived members of this tribe.
Contrary to Clarke's assertion, P. holstonia may be one of
the most derived members of the genus Pressodonta. The
shape of this glochidium approaches that of Alasmidonta, and
its exterior valve sculpturing clearly distinguish it from the remaining members of the genus.
Pegias Simpson, 1900. Type species Marqaritana fabula
The glochidium of P. fabula is quadrate-oval, almost trapezoidal in shape. It is longer than high, with a 77 broadly connected styliform hook and tight looped exterior
valve sculpturing The hook has about 75 microstylets
arranged in three proximal rows and two distal rows.
The adults are characterized by relatively small size
(15-40mm long), absence of valve sculpture, except at the
umbo, incomplete hinge teeth and sexual dimorphism in adult
shell morphology. Pseudocardinal teeth are single in both
valves and lateral teeth may be absent, rudimentary, or of
the usual configuration (two in the right valve and one in the left). The initial sculpture at the umbo is concentric becoming more double looped with age. The soft parts are anodontine in structure, with the outer gill marsupial, distended when filled with young and devided into longitudinal chambers. The inner lamella of the inner gill is free from the visceral mass (Ortmann, 1912; Clarke,
1981a).
Pegias fabula (Lea, 1838)
Glochidium oval quadrate to roundly trapezoidal (Figs.
30a, 30b, 30c). The dorsal margin is straight and 205 +
5.03um (3); 200-210um long. The posterior margin is roundly arcuate and the anterior margin is inflated dorsally while slightly incurved near the ventral terminus. The ventral terminus is slightly rounded and about 35% from posterior to anterior. The length of the valve is 386 ± 1.53um (3) ,*
385-388um, and its height is 322 ± 3.06um (3); 319-325um. 78 The exterior surface is smooth in the area of the adductor
muscle scar, which is very large and lacks pits, and at the
margin of the valve. The valve is otherwise pitted {Figs.
30b, 30c, 30d). The valve surface is not malleated and
tight looped sculpture covers its exterior surface (Fig.
30e) .
The central ligament is 71 + 2.89um (3); 68-73um long
and centered about 45% from posterior to anterior. The
posterior ligament is 60 ± 3.Slum (3); 56-63um in length and
the anterior ligament is 74 + 5.03um (3); 69-79um long.
The hook is styliform, sharply pointed and broadly
connected to the ventral valve margin (Figs. 30b, 30c, 30f).
The hook has about 75 lanceolate microstylets that are
arranged three abreast near the proximal end of the hook and
in a double row distally. About 15 microstylets form a
cluster near the distal end of the hook. Micropoints are
limited to the ventral rim of the valve and along the margins of the microstylets. This leaves a very wide unsculptured distal hook margin.
The glochidium of P. fabula can not be confused with
that of any other species. Its quadrate shape, broadly connected styliform hook, tight looped exterior valve sculpturing and extremely large adductor muscle scar will distinguish it. Clarke (1981a) gives a figure of this glochidium (his fig. 3) and length and height measurements for two specimens: 354um x 309 and 380um x 310um. 79 Alasmidonta Say, 1818. Type species Monodonta undulata
The glochidium of Alasmidonta is high triangular in
shape (pear-shaped) , possess a complex hook with over 100
microstylets, and has exterior valve sculpture ranging from
beaded to large postulate points that resemble the spots on
a leopard (rosettes). The surface of the valve is coarsely
malleated and densely pitted except along the valve margin
and at the umbo.
The adult shell is rhomboidal and inflated with a well
developed posterior ridge. The disc is generally
unsculptured, however wrinkles or low ridges may be present
on the posterior slope. The umbo is generally very high and
inflated with heavy concentric sculpture. Hinge teeth may
be complete or not; pseudocardinal teeth are present and
lateral teeth may be present or absent, sometimes vestigial.
Ortmann (1912) characterized the soft parts as, "only the outer gills are marsupial, when charged, distended at edges, secondary water-tubes present, and ovisacs not subdivided." with the removal of Pressodonta, an additional character
that can be used to distinguish this genus is that the inner
lamella of the inner gill is usually entirely connected to the visceral mass.
Alasmidonta undulata (Say, 1817)
Glochidium pyriform, much higher than long, asymmetric
(Figs. 31a, 31b, 31d) with a length of 353 ± 5.89um (5); 80 343-358um, and a height of 371 ± 5.13um (5); 365-378um. The
dorsal margin is straight and 254 ± 5.59um (5); 247-260um in
length. The posterior margin near the dorsal margin is
outwardly curved becoming straight to slightly incurved
before the ventral terminus. The anterior margin is more
broadly curved than the posterior margin. However, here
again the outward curve of the valve margin is dorsal while
the curvature of the anterior margin before the ventral
terminus is slightly incurved. The points of maximum
anterior and posterior inflation are about 30% from dorsal
to ventral and the ventral terminus is rounded and located about 40% from posterior to anterior. The surface of the valve is coarsely malleated and uniformly pitted except at the umbo and along the valve margin where pits and malleations are absent. An adductor muscle scar is visible in interior view (Fig. 31b, 3Id) however pit density is not reduced. The exterior surface is covered with sparse rosette sculpture separated by areas of beaded sculpture
(fig. 31e) and a larval thread is present (Fig. 3 Id at arrow).
The central ligament is 92 ± 5.19um (3) 89-98um in length and centered about 40% from posterior to anterior
(Figs. 31b, 31d). The posterior ligament is 54 ± 1.15um
(3); 53-55um in length, and the anterior ligament is 104 ±
1.00 (3); 103-105um long. 81 The hook is styliform and covered with numerous (about
120) microstylets and micropoints (Figs. 31b, 31c, 31d,
31f). The microstylets are pyramidal, multifaceted,
arranged in about six proximal rows and reduced to about
four rows distally. Micropoints are found along the ventral
valve margin, at the lateral margins of the microstylets and
for a short distance down the lateral surfaces of the hook.
The unsculptured distal hook margin is wide.
The relationship of the hook to the ventral terminus in
the high pyriform glochidia is slightly different from that
in the subtriangular or depressed pyriform glochidia. With
the extended height of the valve, the ventral terminus becomes more narrowly rounded. In these glochidia there is a tendency for the hook to arise with distal margins almost parallel to the hinge rather than as broad triangular plates with oblique distal margins. In the pyriform glochidia the distal point of the hook arises from this straight sided plate, or the margins of the hook are strongly concave. In either case the point of the hook is very sharp.
This glochidium can be distinguished by its large size, pyriform valve shape, complex hook and unique exterior valve sculpture. Ortmann (1912) described this glochidium as,
"moderately large, higher than long, with strong hooks.
Length 0.34; height 0.36mm." Clarke (1981a) reported length and height measurements of 310um X 370um and gives a figure of this glochidium (Clarke, 1981a, fig. 13). 82 Alasmidonta marqinata Say, 1818
Glochidium pyriform, higher than long, asymmetric
(Figs. 32a, 32b) with a length of 339 ± 2.87um (4);
335-341um, and a height of 365 ± 5.74um (4); 360-372um. The
dorsal margin is straight and 233 ± 0.96um (4); 230-233um in
length. The posterior margin is broadly curved (especially dorsally) and its maximum inflation occurs at about 30% from dorsal to ventral. The anterior margin is more broadly curved than the posterior margin and its maximum inflation occurs at about 40% from the dorsal margin. The side margins are slightly incurved ventrally producing a narrowly rounded ventral terminus which is located about 40% from posterior to anterior. The exterior surface of the valve is coarsely malleated and densely pitted except at the valve margins and at the umbo and the exterior surface is covered with beaded sculpture (Fig. 32d). Fine loose looped sculpture was found near the umbo of one glochidium (Fig.
3 2c) and a larval thread is reported for this species for the first time (Fig. 32i).
The midpoint of the central ligament is about 40% from posterior to anterior and the central ligament is about 70 ±
3.54um (2); 67-73um in length. The posterior ligament is 60
± 1.41um (2); 59-61um long, and the anterior ligament is 104
± 4.95um (2); 100-107um long.
The hook is styliform with many microstylets (about
120) and many micropoints (Figs.32b, 32e). As is A. 83 undulata the distal margin of the hook is parallel to the
ventral margin except at its center where it becomes
strongly curved to a sharp distal point. The microstylets
are pyramidal, multifaceted, arranged in six to seven
proximal rows and reduced to four rows distally.
Micropoints are found along the rim of the ventral terminus,
at the lateral margins of the microstylets and for a short
distance down the lateral surfaces of the hook. The distal
hook margin has a wide unsculptured band.
It was outside the scope of this study to examine the
soft parts of the glochidium. However, it is suggested that
such a study, whether of the topography of the glochidial
soft parts using SEM or by sectioning would produce valuable
information. The following figures demonstrate some of the
structures that could be examined.
Sensory hair cells (Fig. 32f) have been described using
light microscopy (see Lillie, 1895; Wood, 1974), SEM (Giusti et al., 1975; Rand and Wiles, 1982) and transmission
electron microscopy (Zs.-Nagy and Labos, 1969). It is generally thought that during attachment to the host, the
tissues of the host push down on the hair cells and that the
response to this stimulus is prolonged muscle contraction.
However, no mechanism for the transmission of the signal
from the hair cells to the adductor muscle has been proposed, primarily because nerves have never been observed.
It appears from Figure 32f that when the hairs are bent 84 their movement stimulates a ring of tissue, possibly composed of nerve tissue, that encompass the base of the cell (at arrow). Leading from this ring is a tract that may join similar tracts from surrounding hair cells before traveling dorsally to the adductor muscle.
The adductor muscle (Fig. 3 2g) is composed of long cells of contractile elements that attach to the crystalline matrix of the valves. The adductor muscle scar is often visible as a rough elliptical area or by its reduced number of pits. There is no evidence that the muscle cells actually insert within these pits.
The larval mantle cells are five to seven sided (Fig.
32h) and do not appear to be pitted as suggested by Rand and wiles (1982). They suggested that the larval mantle was pitted to correspond to the pits in the valve and that this might facilitate gas exchange, nutrient uptake, or waste elimination. However, if holes in the mantle corresponded to those in the valve there would be holes in the center of the cells figured here, not just along the margins. It is suggested therefore that the holes in these cells are an artifact of drying and that the mantle cells are not normally fenestrated.
This glochidium can be distinguished from that of A. undulata by differences in exterior valve sculpturing.
Otherwise they are very similar. Lea (1858) described this glochidium as subtriangular with a long, straight dorsal 85 line and inflated side margins. He described the hook as
terminating in an arrowhead point. Clarke (1981a) also
described the point of the hook as arrowhead-like. The
arrowhead effect is probably due to the collapse of the
lateral surfaces of the hook and is probably an artifact of
drying. This glochidium has a wide size range: (length x
height) 330um x 360um (Ortmann, 1912); 350um x 380um
(Surber, 1912); 300um x 350um (Utterback, 1915-1916); 341um
x 346um (Clarke, 1981a). Utterback's measurements may be a
result of misprinting Surber's figures. This glochidium is
figured by Lea (1858, pi. 5, fig. 27), Surber (1912, pi. 3,
fig. 42, as A. truncata = A. marginata fide Stansbery et
al. 1985) and Clarke (1981a, fig. 20).
Arcidens Simpson, 1900. Type species Alasmidonta confraqosa
The glochidium of A. confraqosus is pyriform and about as long as high. Anterior and posterior margins are greatly inflated dorsally and slightly incurved ventrally. The ventral terminus is narrowly rounded and the number of rows of microstylets on the hook are not reduced from proximal to distal ends.
Simpson (1900) separated A. confragosus from
Alasmidonta mainly because of the strong sculpture on the disc and posterior slope of the adult. The shell is rhomboidal with an inflated umbo. Hinge teeth are incomplete; pseudocardinal teeth are present, lateral teeth 86 are vestigial or absent. The marsupium of the gravid female is typically anodontine in structure with tripartite water tubes formed in the gravid exterior gills. The marsupia become greatly distended when charged with young and the inner lamella of the inner demibranchs are attached to the visceral mass only along their anterior third, if attached at all.
Arcidens confragosus (Say, 1829)
Glochidium pyriform, about as long as high, asymmetric
(Figs. 33a, 33b) with a length of 359 ± 5.32um (4);
352-363um, and a height of 354 ± 1.41um (2); 353-355um. The dorsal margin is straight and 246 ± 7.16um (5)? 237-252um in length. The posterior margin is produced dorsally and incurved ventrally. Its maximum inflation occurs between
30-40% from dorsal to ventral. The anterior margin is broadly rounded dorsally and incurved just before the ventral terminus. Its maximum inflation occurs at about 50% from the dorsal margin. The ventral terminus is narrowly rounded and about 40% from posterior to anterior. The exterior surface of the valve is coarsely malleated and densely pitted except at the umbo and along the valve margin and a single large depression is visible at the umbo. Dense rosette sculpturing covers the exterior surface of the valve
(Fig. 33e). 87 The central ligament is 71 ± 6.40um (4); 63-78um long
and centered about 42% from posterior to anterior (Figs.
33b, 33g) . The posterior ligament is 68 ± 5.91um (4);
59-72um long, and the anterior ligament is 110 ± 7.14um (4); 100-115um long.
The hook extends from the ventral terminus as a very
strongly biconcave triangular plate (Figs. 3 3b, 3 3c). The
styliform hook has about 80 pyramidal microstylets arranged
in about five rows (Figs. 33d, 33f). The number of rows of microstylets does not change from proximal to distal ends of the hook. Micropoints are limited to the rim of the valve at the ventral terminus and along the microstylet boarder.
The unsculptured distal hook margin is very wide.
This glochidium is similar to that of Alasmidonta but can be distinguished by its equal height and length, its exterior valve sculpture and the arrangement of microstylets on the hook. Length and height measurements are given by
Surber (1912) 355um x 350um, and Clarke (1981a) 359um x
360um, both of whom figure this glochidium; Surber (1912, pi. 1, fig. 5) and Clarke (1981a, fig. 31).
Lasmigona Rafinesgue, 1831. Type species Alasmidonta costata
The glochidium of Lasmigona is pyriform, higher than long, asymmetric, and bears hooks covered with numerous microstylets and micropoints. However, the micropoints do not extend over the edge of the ventral terminus. Exterior 88 valve sculpture is beaded or rosette.
The adult shell is large, compressed, with ridges on
the posterior slope and double-looped umbo sculpture. Hinge
teeth are generally incomplete; pseudocardinal teeth are
generally present, lateral teeth may be present or
vestigial. If lateral teeth are present they are composed
of one thick broad ridge in the right valve and one or two
in the left valve. The soft parts of the adults are
anodontine in structure with tripartite marsupia becoming
distended when charged with young. The inner lamella of the
inner gill is free from the visceral mass or attached along
its anterior third. As presented here, the genus Lasmigona
is restricted to Clarke's (1985) Lasmigona s. s..
Lasmigona costata (Rafinesgue, 1820)
Glochidium pyriform, asymmetric with a straight dorsal
margin and undulate side margins (Figs. 34a, 34b).
Posterior and anterior margins are broadly rounded dorsally
and slightly incurved ventrally. Maximum inflation of the
posterior margin occurs at about 30% from dorsal to ventral
and the maximum inflation of the anterior margin occurs at
about 40% from the dorsal margin. The length of this
glochidium is 344 ± 2.73um (7); 340-348um, and its height is
369 ± 5.68um (7); 363-377um. The exterior valve surface is coarsely malleated and densely pitted except at the valve margins and at the umbo, and the exterior surface is covered 89 with densely beaded sculpture (Pig. 3 4c).
The central ligament is 80 ± 2.49um (5); 78-84um long
and centered at about 45% from posterior to anterior (Fig.
34b). The dorsal margin is 241 + 2.23um (7); 239-245um
long. The posterior ligament is 64 ± 2.77um (5); 61-68um in
length, and the anterior ligament is 99 ± 7.05um (5);
90-105um long.
The hook is styliform, arising from the ventral
terminus as a broadly incurved triangular plate (Figs. 34b,
34e). Microstylets are lanceolate, multifaceted and arranged in about seven proximal rows, reduced to five distal rows. Microstylets number about 100. Micropoints are found at the proximal boarder of the hook but they end abruptly at the ventral rim of the valve. They do not extend onto the exterior valve surface (Fig. 34d) nor do they extend very far onto the lateral surface of the hook.
This leaves a wide unsculptured distal hook margin.
This glochidium can be distinguished by its distinctly pear-shaped outline, its exterior valve sculpture, and hook structure. Glochidia of this species are figured by Lea
(1858, pi. 5, fig. 26, as Marqaritana rugosa = L. costata fide Ortmann and Walker, 1922), Lefevre and Curtis (1910, fig. B, 1912, fig IB), Surber (1912, pi. 1, fig. 7), Arey
(1924, pi. 1, fig. 2) and Clarke (1985, fig. 5). This glochidium has a rather wide range in size: (length x height) Lea, 368um x 400um; Surber, 385um x 390um; Lefevre 90 and Curtis, 350um x 3 90u j t i; Ortmann, 340um x 370um; Clarke,
333um x 364um.
Lasmigona complanata (Barnes, 1823)
Glochidium pyriform, almost symmetrical with a straight
dorsal margin and undulate side margins (Figs. 35a, 35b).
The glochidium is 293 ± 2.90um (6); 289-296um long, and 302
± 6.90um (6); 293-310um high. The dorsal margin is 201 ±
4.69um (7); 195-208um in length and maximum inflation of anterior and posterior margins occur at about 40% from dorsal to ventral. The exterior surface is coarsely malleated and densely pitted except along the valve margin.
The umbo is malleated but not pitted and dense rosette sculpturing covers the exterior surface of the valves (Figs.
35e, 35f ) .
The midpoint of the central ligament is about 42% from posterior to anterior and the central ligament is 64 ±
3.32um (4); 60-68um long. The posterior ligament is 52 ±
1.29um (4); 50-53um in length, and the anterior ligament is
81 ± 5.48um (4); 75-88um long.
The styliform hook is very similar to that of L. costata. Microstylets (about 100) are lanceolate, multifaceted, arranged in six proximal and rows reduced to four rows distally (Figs. 35b, 35c, 35d). Micropoints are few in number and restricted to the proximal margin of the 91 hook. The unsculptured distal hook margin is wide and the hook is located about 40% from posterior to anterior.
This glochidium can be distinguished by its nearly equal length and height, few micropoints and exterior valve sculpture. It is figured by Lea {1858, pi. 5, fig. 29),
Lefevre and Curtis (1910, fig. A, 1912, fig. 1A) , Ortmann
(1911, pi. 89, fig. 11), Surber (1912, pi. 1, fig. 6), Arey
(1921, pi. 1, fig. 1, 2) and Clarke (1985, fig. 8).
Measurements given for this glochidium are: Lefevre and
Curtis, 290um x 300um; Ortmann, 340um x 340um; Surber, 310um x 320um; Clarke, 337um x 337um. This glochidium appears to vary a great deal in size but its relative dimensions remain fairly constant (ie. length = height). Figure 10. Glochidium of Unio elongatulus glaucinus, MAH:2055; a. exterior valve, bar length = 30um; b. interior valve, bar length = 30um; c. styliform hook., bar length = lOum; d. styliform hook, bar length = lQum; e. exterior valve sculpture, bar length = lum; f. hinge, bar length = 2 5um. Figure 11. Glochidium of Anodonta cygnea, OSUM:20911.1; a. exterior valve, bar length = 55um; b. interior valve, bar length = 50um; c. interior valve pitting, bar length = Sum; d. styliform hook, bar length = 20um; e. exterior valve sculpture, bar length = ium; f. hinge, bar length = 40um. Figure 12. Glochidium of Anodonta anatina; a. exterior valve, OSUM:20912.2 , bar length = 55um; b. interior valve, OSUM:20912.2, bar length = 50um; c. exterior valve sculpture, OSUM:20912.1, bar length = lum; d. styliform hook, OSUM: 20912. 2, bar length = 20um; e. larval thread, OSUM:20912.2, bar length = 25um; f. larval thread, OSUM:20912.2, bar length = 15um; g. microstylets, OSUM:20912 . 2 , bar length = Sum. Figure 13. Glochidium of Anodonta beringiana, OSUM:3711.1; a. exterior valve, bar length = 4Sum; b. interior valve, bar length = 50um; c. ventral valve view, bar length = 40um; d. styliform hook, bar length = 10um; e. styliform hook, bar length = 10um; f. styliform hook, bar length = lOum.
95 96
Figure 13. Glochidium of Anodonta berinqiana. Figure 14. Glochidium of Anodonta kenncrlyi; a. cxtciin valve, OSUM:52882.2, bar length = 50um; b. interior valve OSUM:52882 . 2 , bar length = 5Qum; c. lateral OSUM: 52882. 3 , bar length = 55um; d. styiifor:r r.vvh OSUM:52882.2, bar length = 15 urn; o. ox to: io: ■■a.*.* sculpture, CSUM: 5 2 8 8 2 . 3 , bar length : f . j.: r. je OSUM:52882. 3, bar length - 35um. Figure 15. Glochidium of Anodonta g. grandis, OSUM:38467.i0; a. exterior valve, bar length = 55um; b. interior valve, bai length = 55um; c. lateral view, bar length - loom; . styliform hook, bar length = I5um; e. into: it;: *.■ i . -v pitting, bar length - 15um; f. exterior va i ve . ip - ; t: length - 1um. Figure 16. Glochidium of Anodonta c. cataracta; a. exterior valve, OSUM:52462.27 , bar length = 55um; b. interior valve, OSUM: 52462.35 , bar length = 55um; c. hinge, OSUM:52462.27 , bar length = 40um; d. exterior valve sculpture, OSUM: 52462.27, bar length = 2um; e. styliform hook., OSUM:52462.27, bar length = 2 0um. 100
\ I X ”;
Figure 17. Glochidium of Anodonta doliaris, OSUM:26405; a. exterior valve, bar length - 55um; b. interior valve, bat length = 55um; c. exterior valve sculpture, bat length luin; d. styiiform hook, bar length - 2Gum. Figure 18. Glochidium of Anodonta implicata. OSUM:5246 3 . 7 ; a. exterior valve, bar length = 50um; b. interior valve, bai length = 4uum; c. styliform hook, bar length - I Cum; i. valve pitting, bar length = 15um,- c. hinge, bat length ^5um; f. exterior valve sculpture, bar length - iurr. 102
Figure 19. Glochidium of Anodonta suborbiculata, OSUM:13634; a. exterior valve, bar length = 40um; b. interior valve, b j
length = 40um; c. lateral view, bar length = 40um; CL 0 styliform hook, bar length = 10um; c. valve pitting, ba: length - 10um; f. exterior valve sculpture, bai length 2um . 10 3
Figure 20. Glochidium of Anodonta imbecillis; a. exterior valve, UWZY:24971.1, bar length = 5 0um; b. interior valve, OSUM:9436.2, bar length = 60um; c. styliform hook, UWZY: 2497 1 . 1 , bar length = 15um; d. styliform hook, HAH : 4 1 , bar length - 15um; e. hinge, UWZY: 24971 . 1 , bar length - .'.urn; f. exterior valve sculpture, UWZY: 2 4 9 71 . 1 , bar lonuth ..o:v. Figure 21. Glochidium of Anodontoides ferussacianus; a. exterior valve, MAH:989.4, bar length = 50um; b. interior valve, MAH:989.4, bar length = 50um; c. hinge ligament, OSUM:18275.2, bar length = 30um; d. styliform hook, MAH:989.4, bar length = 25um; e. exterior valve sculpture, MAH:989.4, bar length = lum. Figure 22. Glochidium of Simpsonaias ambiqua; a. exterior valve, UWZY:22658, bar length = 40um; b. interior valve, UWZY:22662, bar length = 4 0um; c. lateral view, UWZY:22662, bar length = 45um; d. styliform hook, UWZY:22658, bar length = lOum? e. exterior valve sculpture, OSUM:55995, bar length = 2um; f. hinge, UWZY:22672, bar length = 20um. 106
Figure 23. Glochidium of Strophitus u. undulatus; a. exterior valve, OSUM:49443, bar length = 50um; b. interior valve, OSUM: 52458.4, bar length = 50um; c. lateral view, OSUM:52458.4, bar length = 70um; d. styliform hook, OSUM:52458.4, bar length = 20um; e. exterior valve sculpture, OSUM: 49443, bar length = lum,- f. microstylets, OSUM:52458.4, bar length = lQum. Figure 24. Glochidium of Strophitus subvexus, OSUM:36240; a. exterior valve, bar length = 50um; b. interior valve, bar length = 50um; c. exterior valve, bar length = 5Gum; d. styliform hook, bar length = 20um; e. exterior valve sculpture, bar length = 2um; f. hinge, bar length = 3 5um. Figure 25. Glochidium of Pressodonta viridis, OSUM:47518; a. exterior valve, bar length = 45um; b. interior valve, bar length = 45um; c. lateral view, bar length = 45um; d. styliform hook, bar length = 15um; e. exterior valve sculpture, bar length = 2um; f. interior valve pitting, bar length = lOum. Figure 26. Glochidium of Pressodonta heterodon, OSUM:25106.2; a. exterior valve of immature glochidium, bar length = 45um,- b. interior valve, bar length = 70um; c. exterior valve, bar length = 45um; d. interior valve, bar length = 60um; e. styliform hook, bar length = 10um; f. exterior valve sculpture, bar length = lum.
109 110
Figure 26. Glochidium of Pressodonta heterodon. 'Jk '■0th
e
Figure 27. Glochidium of Pressodonta compressa; a. exterior valve, OSUM:23179.1, bar length = 45um; b. interior valve, OSUM:23179.1, bar length = 45um; c. lateral view, MAH:702, bar length = 70um; d. styliform hook, MAH:702, bar length = 30um; e. exterior valve sculpture, MAH:702, bar length - lum; f. microstylets, MAH:702, bar length = lOum. Figure 28. Glochidium of Pressodonta subviridis; a. exterior valve, OSUM:27131.68, bar length = 55um; b. interior valve, OSUM:27131 .68, bar length = 80um; c. exterior valve sculpture, OSUM: 27131.66, bar length = lum,- d. styliform hook, OSUM:27131.68, bar length = 15um. 113
Figure 29. Glochidium of Pressodonta holstonia, OSUM:55826.6; a. exterior valve, bar length = 45um; b. interior valve, bar length = 40um; c. exterior valve sculpture, bar length - lum; d. styliform hook, bar length = 10 um . Figure 30. Glochidium of Pegias fabula; a. exterior valve, OSUM:41308.3, bar length = 5 Sum; b. interior valve, OSUM:41309.1, bar length = 5 Sum; c. exterior valve, OSUM:41308.3, bar length = 5Sum; d. lateral view, OSUM:41308.3, bar length = 55um; e. exterior valve sculpture, OSUM:41308.3, bar length = 2um; f. styliform hook, OSUM:41309.1, bar length = 20um.
114
116
Figure 31. Glochidium of Alasmidonta undulata, OSUM:52434.4; a. exterior valve, bar length = 60um,- b. interior valve, bar length = 55um; c. styliform hook, bar length = 20um; d. interior valve, bar length = 50um; e. exterior valve sculpture, bar length = lum; f. micropoints, bar length - lOum. Figure 32. Glochidium of Alasmidonta marginata; a. exterior valve, MAH:724.1, bar length = 55um; b. interior valve, MAH:724.1, bar length = 45um; c. exterior valve sculpture, MAH:724.1, bar length = lum; d. exterior valve sculpture, MAH:277.1, bar length = lum; e. styliform hook, MAH:277.1, bar length = 2Bum; f. hair cell, MAH:724.1, bar length = Bum; g. adductor muscle, MAH: 724.1, bar length = Bum; h. mantle cells, MAH:724.1, bar length = 10um; i. larval thread, MAH:724.1, bar length = lOum.
117 118
Figure 32. Glochidium of Alasmidonta marqinata Figure 33. Glochidium of Arcidens confragosus, OSUM:52015; a. exterior valve, bar length = 65um; b. interior valve, bar length = 65um; c. styliform hook, bar length = 25um; d. styliform hook, bar length = 5um; e. exterior valve sculpture, bar length = lum; f. microstylets, bar length - 5um,- g. hinge, bar length = 40um. 120
t
4 V
Figure 34. Glochidium of Lasmigona costata; a. exterior valve, MAH:585, bar length = 50um; b. interior valve, MAH:279.1, bar length = 50um; c. exterior valve sculpture, MAH:585, bar length = lum; d. styliform hook, MAH:58 5, bar length = 20um; e. styliform hook, MAH:585, bar length = 2 0um. Figure 35. Glochidium of Lasmiqona complanata, MAH:278.2; a. exterior valve, bar length = 45um; b. interior valve, bar length = 45um; c. styliform hook, bar length = 15um; d. styliform hook, bar length = 20um; o. exterior valve sculpture, bar length = lum; f. exterior valve sculpture, bar length = 2um. 122 Subfamily Ambleminae (Rafinesque, 1820) Morrison, 1955. Type
genus Amblema Rafinesque, 18 20. Type species Unio plicatus Say 1817.
Too few species were examined to suggest a phylogeny
for this subfamily based on glochidial characters. The
arrangement of species used here is that of Stansbery and
Borror (1983). However, characters found upon examination
of these species serve to contrast the glochidia of this
subfamily with that of the Lampsilinae (ie. micropoint
structure, location and arrangement; central ligament
position; valve outline and morphometries). The absence of
dorsal alae in the Ambleminae further distinguish the
members of this subfamily from the Lampsilinae.
Maqnonaias Utterback, 1915. Type species Unio nervosus
The subelliptical glochidium of Magnonaias is much
higher than long with unequal lateral margins, a straight dorsal margin and a narrowly rounded ventral margin. Tight
looped exterior valve sculpture is present and micropoints
are lanceolate. A larval thread was found in both species examined.
The adults of this genus are very large and possess moderately inflated shells with low umbones. The umbo, disc and posterior slope are heavily sculptured, the periostracum
is dark and hinge teeth are heavy. The marsupia are composed of all four gills and these become greatly 123 distended when charged. unlike the other members of this
subfamily, glochidia are stored over winter in the marsupia.
The glochidia examined during this study were mature during
October and November.
Magnonaias nervosa (Rafinesque, 1820)
Glochidium subelliptical (Figs. 36a, 36b) with a length of 261 + 6.58um (4); 254-268um, and a height of 346 ± 4.78um
(4); 340-350um. The dorsal margin is straight and 150 ±
3.27um (6); 145-155um in length. Lateral margins are gently curved but unequal and the ventral margin is narrowly rounded. Maximum inflation of the posterior margin occurs about 70% from dorsal to ventral, and maximum inflation of the anterior margin occurs about 40% from the dorsal margin.
Tight looped sculpture covers the exterior surface of the valve (Fig. 36f), and a coiled larval thread is present
(Figs. 36c, 36d). Howard (1914c) was the first to describe this unique coiled larval thread and Surber (1915) noted that, "this coiled gland is a prominent feature of the mature glochidium." My figures show that the larval thread not only coils around the adductor muscle, as occurs in all other species that possess a larval thread, but that it also coils around itself.
The central ligament is 50 ± 1.53um (3); 49-52um long and centered about 44% from posterior to anterior (Figs.
36b, 36g). The anterior ligament is 60 + 2.00um (3); 124 60-63um long, and the posterior ligament is 43 ± 0.58um (3);
43-44um in length.
Micropoints are lanceolate and arranged in broken
vertical rows on a narrow ventral flange, and along the rim
of the ventral margin of the valve (Pigs. 36b, 36e). They
cover most of the surface of the ventral flange and leave a
very narrow unsculptured distal flange margin.
Surber (1915) stated, "notwithstanding its great
variation in size, and even outline, this species can not be
readily confused with any other, even though the larval
gland may have been absorbed..." Surber (1912), Howard
(1914c) and Surber (1915) give length and height measurements of 260um x 340um, 250-260um x 316-340um, and
250-280um x 300-380um for this glochidium (as Ouadrula heros
= M. nervosa fide Stansbery et al., 1985). This glochidium
is figured by Lea (1858, pi. 5, fig. 3, as Unio multiplicatus = M. nervosa fide Stansbery et al., 1985),
Surber (1912, pi. 2, fig. 32), Howard (1914, pi. 3, fig. 21, pi. 5, fig. 35), Surber (1915, pi. 1, fig. 10) and Utterback
(1915-1916, fig. 3a, 3b). Surber's, Howard's and utterback's figures agree with mine while Lea's does not.
Maqnonaias boykiniana (Lea, 1840)
I was unable to clean glochidia of this species, however the examination of the exterior surface features of this glochidium, its shape and size, ally M. boykiniana with 125 M. nervosa. The glochidium of M. boykiniana is
subelliptical with a straight dorsal margin, a narrowly
rounded ventral margin and gently but unequally curved
lateral margins (Fig* 37a). Tight looped sculpture is
present on the exterior surface of the valve (Fig. 37c) and
micropoints are lanceolate (Fig. 37d). Length, height and
hinge length of a single specimen are 24Sum x 350um x 150um,
all within the ranges established for the glochidium of M.
nervosa. The only glochidial character that distinguishes
these two species appears to be their larval threads. As discussed above, the larval thread of M. nervosa is coiled around itself as well as the adductor muscle. The larval thread in M. boykiniana, however, is only coiled around the adductor muscle (Fig. 37b).
Plectomerus Conrad, 1853. Type species Unio dombevana
The glochidium of P. dombevana is subelliptical with a straight dorsal margin, gently curved lateral margins and a broadly rounded ventral margin. The central ligament is far posterior, micropoints are lanceolate and its exterior surface sculpturing is loose looped.
The adult shell is trapezoidal in outline with a prominent posterior ridge, a deep umbo cavity, complete hinge teeth and sculpture on the disc and posterior slope.
All four gills serve as marsupia in the female, and larval development and release occur during the spring and summer 126 {short term breeder). It should be noted that Ortmann
(1912) found that Crenodonta trapezoides (= P. dombevana
fide Walker, 1928) often restricted the marsupia to the outer gills.
Plectomerus dombevana (Valenciennes, 1827)
Glochidium subelliptical (Figs. 38a, 38b) with a length of 226 ± 2.99um (10); 223-231um, and a height of 246 ±
7.07um (10); 238-259um. The dorsal margin is straight and
133 + 1.36um (11); 130-135um long. Lateral margins are gently and equally curved, symmetrical, and the ventral margin is semicircular. The surface of the valve is finely malleated and pits are numerous (Fig. 38e). The sculpture of the exterior valve surface is loose looped (Figs. 38c,
38h) and as is shown in Figure 38c the larval valve has an exterior membrane that is at least analogous, if not homologus, with the periostracum of the adult. It is also evident from this micrograph that the exterior valve sculpture occurs within this membrane.
The central ligament is 44 ± 2.06um (4); 42-47um long and centered about 40% from posterior to anterior (Figs.
38b, 38d). The anterior ligament is 56 + 3.59um (4);
51-59um long, and the posterior ligament is 32 ± 1.89um (4);
31-35um in length.
Micropoints are lanceolate and sharply pointed (Figs.
38f, 38g). They are arranged in broken rows on the rim of 127 the ventral margin of the valve and on a narrow ventral flange. The surface of the ventral flange is mostly covered with micropoints and the unsculptured distal flange margin is narrow.
No published figure or measurements for this glochidium were found.
Tritogonia Agassiz, 1852. Type species Obliquaria verrucosa
The glochidium of T. verrucosa is very small, subelliptical in outline, and primitive in many regards.
Micropoints are small lanceolate points that lack organization on the ventral rim of the valve, a ventral flange is absent, and the surface of the valve is rough with no apparent exterior valve sculpture.
The shell of the adult, in contrast to that of the larval stage, is large with sculpturing on the disc and posterior slope. The species has a sharp posterior ridge, white to purple nacre and sexually dimorphic shells. In gravid females, all four gills are marsupial and the marsupia become pad-like but not greatly distended when charged with young.
Tritogonia verrucosa (Rafinesque, 1820)
Glochidium subelliptical to subrotund {Figs. 39a, 3 9b) with a length of 90 ± 3.38um (6); 85-94um, and a height of
100 ± 1.75um (6); 97-101um. The dorsal margin is slightly 128 curved and 44 ± l.llum (7); 43-46um long. Lateral margins
are gently and equally curved and the ventral margin is
semicircular. The exterior surface is rough and had only a
few pits (Fig. 39e).
The central ligament is 32 ± 1.47um (6); 30-34um long
and centered about 45% from posterior to anterior (Figs.
39b, 39d) . The anterior ligament is 8 i l.Slum (6); 6-9um
long, and the posterior ligament is 4 i 0.82um (6); 3-5um in
length. The central ligament comprises about 75% of the total length of the hinge.
Micropoints are extremely small, almost undetected even at high magnification, and unorganized (Fig. 39c). They are located on the rim of the ventral valve margin and upon the exterior surface of the valve. No ventral flange was found.
This glochidium is figured by Surber (1912, pi. 2, fig.
31, as T. tuberculata = T. verrucosa fide Ortmann, 1919) who gives length and height measurements of 8Sum x 90um.
Quincuncina Ortmann, 1922. Type species Quincuncina burkei
The glochidium of Quincuncina infucata is subelliptical, densely pitted, with rough exterior valve sculpture and unique micropoints. As many as seven lanceolate points arise from a single base on a wide ventral flange. These are referred to here as coronal micropoints.
The adult shell is round to subelliptical in outline with heavy ridges on the posterior slope and the disc. The 129 ridges are usually broadly V-shaped with the points of the v
converging from ventral to dorsal on the low posterior
ridge. These ridges may be broken up ventrally into nodules
that are arranged in a more or less quincuncial pattern.
The marsupia are pad-like when charged with young and
composed of all four gills.
Quincuncina infucata (Conrad, 1834)
Glochidium subelliptical (Figs. 40a, 40b) with a short
hinge line, equally curved lateral margins and a broadly
curved ventral margin. The length of this glochidium is 240
± 4.00um (4); 234-242um, and its height is 283 ± 5.68um (4);
275-288um. The dorsal margin is straight and 103 ± 1.34um
(5); 102-105um in length. The surface of the valve is
densely pitted, except along the valve margin, and the fine
structure of the exterior surface is rough (Fig. 40f).
The central ligament is 56 ± 2.8 3um (2); 54-58um long
and centered about 48% from posterior to anterior (Fig.
40g). The anterior ligament is 28 ± 0.71um (2); 27-28um
long, and the posterior ligament is 21 ± 1.54um (2); 20-22um
in length.
The most striking feature of this glochidium is its
unusual micropoint structure (Figs. 40c, 40d, 40e). The more proximal micropoints resemble crowns in which the bases
of the micropoints are fused. The number of points in each
"crown" range from seven along the proximal margin of the 130 flange to two points distally. The furthest micropoints on
the flange are simple lanceolate points. The micropoints do
not extend onto the ventral rim or upon the ventral margin
of the valve but cover about 90% of the ventral flange
leaving a narrow unsculptured distal flange margin.
No published figures of this glochidium were found.
This glochidium will not be confused with that of any other
species examined because of its unique micropoints.
Elliptic Rafinesque, 1820. Type species Unio crassidens
The glochidium of Elliptio is roundly subtriangular
(Surber 1915, pi. 1 fig. 13, of E. crassidens) to subelliptical (see below). Micropoints are small, lanceolate points located on the ventral rim of the valve and on a narrow ventral flange. As in most species of this subfamily the glochidia have the central hinge ligament positioned far posterior of center. Ortmann (1912) gives
130um x 150um for the length and height of the glochidium of
E. crassidens and Surber (1912) gives 150um x 160um for length and height of this glochidium. The glochidium of
Elliptio dilatata is larger than that of the type species and it has a different valve outline.
The adult has a solid, elliptical to triangular valve without sculpture on the disc or posterior slope and a dark periostracum. Umbo sculpture is double-looped if present, hinge teeth are complete and the nacre may be white but 131 usually is purple. In the female only the outer gills are
marsupial. When charged with young the marsupia do not
become distended, however they may appear pad-like.
Elliptio dilatata (Rafinesque, 1820)
Glochidium subelliptical (Figs. 41a, 41b) with a length
of 216 ± 4.27um (4); 210-219um, and a height of 221 ± 3.00um
(4); 219-225um. The dorsal margin is straight and 143 ±
2.99um (4); 140-147um in length, and the ventral margin is
semicircular. Lateral margins are subequal, with the
anterior margin slightly more produced than the posterior margin. Very few pits are located in the valve and pitting
is eliminated altogether in the adductor muscle scar (Fig.
41d). Loose looped sculpture covers the exterior surface of
the valve (Fig. 41c).
The central ligament is 48 ± 3.54um (2); 45-50um long and centered about 43% from posterior to anterior (fig.
41f). The anterior ligament is about 56um long and the posterior ligament is 38 ± 2.12um (2); 36-39um in length.
Micropoints are lanceolate and located on the ventral rim of the valve and on a narrow ventral flange (Figs. 41b,
41e). They are arranged in broken vertical rows and cover most of the area of the flange. The unsculptured distal flange margin is narrow.
This glochidium is figured by Lea (1874, pi. 21, fig.
10, as Unio gibbosus = E. dilatata fide Ortmann and Walker, 132 1922), Lefevre and Curtis (1910, fig. N; 1912, fig. lo, as
U. gibbosus). Ortmann (1911, pi. 89, fig. 7, as E. gibbosus) and Surber (1912, pi. 2, fig. 38, as U. gibbosus). Lefevre and Curtis (1910, 1912) give length and height measurements of 220um x 190um for this glochidium, Surber (1912) gives
200um x 215um, Ortmann (1912) gives 200um x 220um, and
Ortmann (1919, as E. cupreus = E. dilatata fide Johnson,
1970) gives 200um x 200um. 133
Figure 36. Glochidium of Magnonaias nervosa; a. exterior valve, OSUM:54178, bar length = 50um; b. interior valve, OSUM:178, bar length = 50um; c. larval thread, OSUM:54178, bar length = 25um; d. larval thread, OSUM:54178, bar length = 5um; e. micropoints, OSUM: 54178, bar length - 5um; f. exterior valve sculpture, OSUM:1986:22, bar length - 2um; g. hinge, OSUM:178, bar length = 20um. Figure 37- Glochidium of Magnonaias boykiniana, OSUM:51107.5; a. exterior valve, bar length = 50um; b. larval thread, bar length = 25um; c. exterior valve sculpture, bar length = lum; d. micropoints, bar length = Sum. Figure 38. Glochidium of Plectomerus dombevana; a. exterior valve, OSUM:53273.3, bar length = 35um; b. interior valve, OSUM:53273.3, bar length = 3 5um; c. exterior valve sculpture and torn exterior valve membrane, OSUM:53273.3, bar length = 2um; d. hinge, OSUM:53273.2, bar length = 25um; e. interior valve pitting, OSUM:42011, bar length = 10um; f. micropoints, OSUM:53273.3, bar length = 5um; g. micropoints, OSUM:42011, bar length = 3um; h. exterior valve sculpture, OSUM:42011, bar length = lum. Figure 39. Glochidium of Tritogonia verrucosa, MAH:654.X; a. exterior valve, bar length = 15um; b. interior valve, bar length = 15um; c. micropoints, bar length = 5um; d. hinge, bar length = 7um; e. exterior valve sculpture, bar length = 2um. Figure 40* Glochidium of Quincuncina infucata; a. exterior valve, OSUM:48537.2, bar length = 40um; b. interior valve, OSUM:48537.2, bar length = 40um; c. micropoints, OSUM:48537.2, bar length = Sum; d. micropoints, OSUM:48537.2, bar length = 5um; e. micropoints, OSUM:48537.1, bar length = 2um; f. exterior valve sculpture, OSUM:48537.1, bar length = 2um; g. hinge, OSUM:48537.1, bar length = 15um. 138
c d
e f j
Figure 41. Glochidium of Elliptio dilatata, MAH:946.9; a. exterior valve, bar length = 35um; b. interior valve, bar length = 3 5um; c. exterior valve, bar length - lum; d. interior valve, bar length =10um; e. micropoints, bar length = Sum; f. hinge, bar length = 20um. 139 Subfamily Lampsilinae (Von Ihering, 1901) Ortmann, 1912.
Type genus Lampsilis Rafinesque, 1820. Type species Unio
ovatus Say, 1817.
The phylogeny of this subfamily based solely on the
glochidium leads to an arrangement of species that is not
far from that proposed by Ortmann (1912). Based on glochidial structures, Ptychobranchus is clearly the most primitive type within this subfamily. Its fairly small size, round subelliptical shape, sparse unorganized micropoints and undifferentiated ventral valve margin ally this genus with the primitive Ambleminae. However, the position of the central ligament and the presence of dorsal alae (in two of the four species) represent derived characters that unite this genus with the higher
Lampsilinae. The arrangement of species described in this section parallels the development of a number of glochidial character states; dorsal alae become more developed, longer and more arched throughout this lineage, valve outline becomes more straight sided and the glochidium more or less fan-shaped, and the ventral flange increases in size and complexity. A phylogeny of the Lampsilinae based on these structures begins with Ptychobranchus to Actinonaias,
Obovaria, Liqumia. Venustaconcha, Villosa and Lampsilis.
Off-shoots from this main lineage include: 1) Obliquaria,
Cyproqenia and Dromus; 2) Ellipsaria. Leptodea. Lastena and
Potamilus; 3) Epioblasma. 140 Ptychobranchus Simpson, 1900. Type species Obliauaria
fasciolaris.
The glochidium of Ptychobranchus is subelliptical with
a smooth exterior surface. Dorsal alae, if present are only
small swellings at the dorsal lateral margins of the valve
and exterior valve sculpturing is loose looped. Micropoints
are unorganized, few in number, very small and located on
the ventral rim of the valve rather than on a wide ventral flange.
The shell of the adult is elliptical to triangular,
solid, generally unsculptured and usually rayed with fine green lines on a yellow to green periostracum. Sculpture, if present, is limited to the posterior slope and umbo. The most striking character of the genus is extreme to moderate infolding of the marsupia. The marsupia are restricted to the posterior three fourths of the outer gills and contain the glochidia within club-shaped ovisacs. These ovisacs are released entire through the edges of the marsupia. They are intricately marked, about a centimeter to a centimeter and a half long, resemble minnows and probably attract the fish host (Morrison, 1973).
Ptychobranchus fasciolaris (Rafinesque, 1820)
Glochidium subelliptical, higher than long (Figs. 42a,
42b) with a length of 173 ± 2.89um (3); 170-175um, and a height of 187 ± 6.81um (3); 182-195um. The dorsal margin is 141 slightly curved and 83 ± 4.93um (3); 80-89uin in length.
Anterior and posterior margins are about equally curved to a
maximum inflation at about 60% from dorsal to ventral and
the ventral margin is broadly rounded. The surface of the
valve is smooth with only a few pits, and dorsal alae are
absent. Loose looped sculpturing covers the exterior
surface of the valve (Fig. 42e).
The central ligament is 38 ± 2.83um (2); 36-40um long
and centered about 49% from posterior to anterior. The
posterior ligament is 21 ± 2.12um (2); 19-22um long and the
anterior ligament is 24 ± 2.83um (2); 22-26um in length.
Micropoints are very small, few in number (Figs. 42c,
42d) and located on the ventral margin of the valve rather
than on a ventral flange. In this glochidium the entire ventral rim is sharp and probably cuts the tissues of its
h o s t .
This glochidium can be distinguished by its small size, central ligament position and its very simple ventral margin. It is figured by Lea (1858, pi. 5, fig. 12, as Unio phaseolus = P. fasciolaris fide Ortmann and Walker, 1922) and Ortmann (1911, pi. 89, fig. 14, as P. phaseolus) .
Ortmann (1912) gave 170um x 190um for length and height of this glochidium and noted that Lea's figure does not represent its shape or size accurately. The glochidium of
P. fasciolaris is much smaller than that of Liqumia recta 142 rather than, as pictured by Lea (1858), larger than that
species.
Ptychobranchus occidentalis (Conrad, 1836)
Glochidium subelliptical, higher than long (Figs. 43a,
43b) with a length of 200 ± 4.24um (2); 197-203um, and a height of 238 ± 4.9Sum (2); 234-241um. The dorsal margin is slightly curved and 102 ± 1.53um (3); 101-104um in length.
Anterior and posterior margins are equally and gently curved to their maximum inflation at about 60% from dorsal to ventral and the ventral margin is broadly curved. The valve is sparsely pitted, dorsal alae are absent, and loose looped sculpture covers its exterior surface (Fig. 43c).
The midpoint of the central ligament is about 47% from the posterior margin and its length is 46 ± 2.83um (2);
44-48um (Figs. 43b, 43d). The anterior ligament is 32 ±
2.83um (2); 30-34um in length, and the posterior ligament is
25 ± 2.12 (2); 23-26um long.
As in P. fasciolaris, the ventral flange is poorly developed. However, moderate sized micropoints are present on the ventral rim of the valve. They are lanceolate and unorganized.
This glochidium is slightly larger than that of P. fasciolaris and is further distinguished from that species by its larger and more numerous micropoints. No published figures of this glochidium were found. 143 Ptychobranchus qreeni (Conrad, 1834)
Glochidium subelliptical, higher than long, symmetrical
(Figs. 43e, 43f) with a length of 187 ± 3.61um (3);
183-190um, and a height of 227 ± 1.15um (3); 226-228um. The
dorsal margin is slightly curved and 93 + 3.06um (3);
90-96um in length. Anterior and posterior margins are equal
and slightly curved to their point of maximum inflation at
about 70% from the dorsal margin, and the ventral margin is
broadly rounded. Very few pits occur in the valve and the
exterior surface sculpture is loose looped (fig. 43g) .
Dorsal alae are present but very small, and oriented almost
perpendicular to the hinge.
The central ligament is about 49um long and centered at
48% from posterior to anterior. The length of the anterior
ligament is about 26um and the length of the posterior
ligament is 21um.
Micropoints are found on the ventral rim of the valve
(Fig. 43h). They are small, lanceolate and unorganized. A ventral flange is not present.
This glochidium is about the same size as that of P.
fasciolaris. however it can be distinguished from this
species by its dorsal alae and micropoints. This glochidium
is figured by Lea (1858, pi. 5, fig. 16, as Unio woodward!anus = P. qreeni fide Ortmann, 1923-1924). His
figure is essentially correct except for size. Glochidia of 144 Lampsilis ovata and Lampsilis fasciola are larger than those
£* qreeni rather than smaller as figured by Lea.
Ptychobranchus subtentum (Say, 1825)
Glochidium subelliptical, higher than long, symmetrical
(Figs. 44a, 44b) with a length of 190 ± 5.54um (5);
181-195um, and a height of 241 ± 5.76um (5); 2 3 6-251um. The
dorsal margin is slightly curved and about as long as that
in P. fasciolaris, 85 ± 2.88um (6); 82-90um long. The
anterior and posterior margins are about straight to their
maximum inflation at about 60% from dorsal to ventral. Here
they begin to curve and form a broadly rounded ventral margin. The surface of the valve is sparsely pitted and the
exterior sculpture is loose looped (Fig. 44c). An adductor muscle scar is evident in interior view (Figs. 44b, 44d,
44f) and dorsal alae are present although very small.
The central ligament is 37 + l.ISum (3); 36-38um in
length and centered about 48% from posterior to anterior
(Figs. 44b, 44d). The anterior ligament is 25 ± 0.58um (3);
25-26um long, and the posterior ligament is 22 ± 2.08um (3);
20-24um in length.
Micropoints are present on the ventral rim of the valve
(Fig. 44e). They are small, numerous and unorganized. They cover a large portion of the ventral rim and leave a very narrow unsculptured distal margin. 145 This glochidium can be distinguished by its relatively
short hinge line, simple micropoints and small dorsal alae.
Ortmann (1912) compared the glochidium of this species with
that of P. fasciolaris but noted that the glochidium of P.
subtentum is larger than that of P. fasciolaris. He gave
180um x 220um for the length and height of P. subtentum
glochidia. This glochidium is figured by Ortmann (1912, pi. 29, fig. 5).
Obliquaria Rafinesque, 1820. Type species Obliguaria reflexa
The glochidium of O. reflexa is almost round in outline with a slightly curved dorsal margin and broadly rounded anterior, posterior and ventral margins. Micropoints are
located on the ventral rim of the valve and on a narrow ventral flange.
The adult shell is round in outline and is distinguished by a row of large knobs running from the umbo to the ventral margin. The knobs alternate from one valve to the other so that they are not directly across, but off-set, from each other. The marsupium of this species consists of a few water tubes at about or slightly behind center of the outer gills. when filled with young this portion of the gill becomes greatly distended so that the ventral edge of the gill extends far beyond the remaining non-marsupial gill. The glochidia are held within ovisacs and these ovisacs are released entire from the female. 146 Obliquaria reflexa Rafinesque, 1820
Glochidium subrotund, symmetrical (Figs. 45a, 45b, 45c) with a length of 217 ± 3.46um (3); 213-219um, and a height of 215 ± 8.14um (3); 206-221um. The dorsal margin is slightly curved outward and is 122 ± 4.16um (3); 119-127um in length. The remaining valve margin is round with the maximum inflation of both side margins occurring at about
50% from dorsal to ventral. The exterior surface is malleated and pitted except along the valve margin where the shell is fairly smooth. within this smooth marginal area longitudinal ridges are found (Fig. 45c). Dorsal alae are a b s e n t .
The central ligament is centered about 46% from posterior to anterior and is longer than either the anterior or posterior ligaments. The length of the central ligament is 53 ± 1.41um (2); 52-54um. The anterior ligament is 41 ±
4.95um (2); 37-44um long, and the posterior ligament is 31 ±
0.71um (2); 30-31um long.
Micropoints are found on the ventral rim and upon a narrow ventral flange (Figs. 45b, 45c, 45d). They are large, bluntly pyramidal in shape and decrease in size distally. They are arranged in broken vertical rows that extend two thirds the length of the flange leaving a narrow unsculptured distal flange edge. The microstylets are also seen to extend laterally to about the point of maximum lateral inflation of the valves. 147 Lefevre and Curtis (1910, 1912), Surber (1912) and
Ortmann (1912) give the following measurements for this
glochidium; 230um x 225um, 225um x 235um, and 220um x 220um.
Ortmann (1919) noted that the shape of this glochidium, "may
best be compared with a circle a small section of which is
cut off." This glochidium can be distinguished by its shape
and micropoints. It is figured by Lefevre and Curtis (1910,
fig. M, 1912, fig. IN), Surber (1912, pi. 2, fig. 39) and
Ortmann (1912, pi. 20, fig. 1).
Cyprogenia Agassiz, 1852. Type species Obovaria steqaria
Sterki (1898) described the glochidium of Unio irrorata
(= C. steqaria fide Ortmann, 1919) as, "considerably longer
than high [with] numerous distinct crowded, concentric lines
of growth." Ortmann (1912) found this glochidium , "rather
small, almost semicircular, distinctly longer than high,"
and noted that its shape, "approaches to a degree, that of
Dromus." Ortmann mentions that he was not able to see the
concentric growth lines described by Sterki.
The adult shell of this species is densely sculptured with zig-zag ridges and small knobs. The periostracum is yellowish-green with dark green rays and the umbo has double-looped sculpture. The gravid marsupium consists of
ten or fewer ovisacs, centrally located in the outer gill.
When charged with young the ovisacs become enlarged ventrally, reaching far beyond the edge of the non-marsupial 148 gill and coil in a spiral beyond the gill edge. The
placentae consist of a solid gelatin in which the glochidia
develop and are discharged entire. They are light red in
color and probably attract a fish host (Chamberlain, 1934).
Cyprogenia steqaria (Rafinesque, 1820)
Glochidium elongate-oval, subrotund (Figs. 46a, 46b)
with a length of 206 t 2.08um (3); 204-208um, and a height
of 167 + 3.06um (3); 164-170um. The dorsal margin is
straight and long, with a length of 116 ± 3.00um (5);
113-120um. Anterior and posterior margins are greatly
curved, mirror images of each other and farthest apart near
their midpoints. The exterior surface is generally smooth,
lacking malleations and with only a few pits. As pointed out by Sterki (1898), concentric ridges are visible but they were found only near the margins of the valve. The disc is
smooth except for loose looped exterior valve sculpturing
(Fig. 46c). Dorsal alae are absent.
The midpoint of the central ligament is about 45% from posterior to anterior and its length is 38 ± 2.65um (3);
35-40um. The posterior ligament is 32 ± 1.53um (3); 30-33um
in length, and the anterior ligament is 45 ± 2.08um (3);
43-47um long (Figs. 46b, 46d).
Micropoints are lanceolate, bluntly pointed and located on the ventral rim of the valve, as in Cyprogenia aberti 149 (described below, Fig. 46g, 46h). A well developed ventral
flange is absent.
This glochidium is similar to that of C. aberti. The
glochidium of C. stegaria can be distinguished, however, by
its more broadly rounded valve outline. Sterki (1898),
Surber (1912) and Ortmann (1912) give the following
measurements for length and height; 210um x 170um, 210um x
18Sum, and 180um x 150um. This glochidium is figured by
Ortmann (1911, pi. 19, fig. 6, as C. irrorata) and Surber
(1912, pi. 1, fig. 11, as C. irrorata).
Cyprogenia aberti (Conrad, 1850)
Glochidium elongate oval, subrotund (Figs. 46e, 46f) with a length of 208 ± 7.03um (6); 200-218um, and a height of 154 + 7.79um (6); 143-161um. The dorsal margin is straight and 131 ± 4.18um (7); 125-136um long. Anterior and posterior margins are equally curved and they reach their maximum inflation at about 50% from dorsal to ventral. The ventral margin is flatly curved and dorsal alae are absent.
The central ligament is centered about 46% from posterior to anterior and is 31 ± 3. Hu m (5); 28-36um long
(Figs. 46f, 46i). The anterior ligament is 54 ± 6.04um (5);
48-61um in length, and the posterior ligament is 44 ± 3.13um
(5); 41-49um long. 150 Micropoints are lanceolate, bluntly pointed and
unorganized on the ventral margin (Figs. 46g, 46h). A
ventral flange is only poorly developed.
This glochidium is essentially like that of C. stegaria
except as noted above. The only other glochidium that
approaches this shape is that of Dromus dromas. However,
the glochidium of D. dromas would not be confused with
either of these because of its extreme valve depression. No
published figures of the glochidium of C. aberti were found.
Dromus Simpson, 1900. Type species Unio dromas
The extreme morphological depression of the glochidium
of this species will serve to distinguish it from all other
species. Dorsal alae are absent, micropoints are lanceolate
and unorganized on the ventral rim of the valve, and the
central ligament is short. In many regards the members of
the Obliquaria - Cyprogenia - Dromus line are not far from
the glochidia of the Ambleminae. The members of these
genera are considered here because they are long term
breeders and because they restrict their marsupia to a
portion of the exterior demibranchs.
The shell of the adult is subrotund to triangular. It has a yellowish-green periostracum covered with many fine
green rays. The marsupium consists of many ovisacs, occupying the posterior portion of the outer gill. The
ovisacs are not very large. However, when charged with 151 young, the marsupium extends entirely beyond the original
edge of the gill. Placentae conform to the shape of the
ovisac and are released entire. As in Qbliquaria and
Cyproqenia, with which this genus is most closely allied,
the worm-like masses of glochidia and conglutinate probably
attract the fish host.
Dromus dromas (Lea, 1834)
Glochidium fabelliform or bean-shaped, much longer than high with a straight dorsal margin, narrowly rounded anterior and posterior margins, and a broadly curved ventral margin (Figs. 47a, 47b). The glochidium is 224 ± S.09um
(5); 219-230um long, and 118 ± 2.49um (5); 114-120um high.
Its hinge margin is 174 ± 8.65um (6); 160-182um long.
Anterior and posterior margins are equal and their points of maximum inflation occur about 30% from the dorsal margin.
The exterior surface of the valve is smooth, however pits are evident in internal view (Figs. 47b, 47c, 47d) . Valve pitting is not uniform; pits are absent at the valve margins, present but few in number near the valve margin
(Fig. 47c), and more numerous in the central portion of the valve (Fig. 47c). Dorsal alae are absent.
The central ligament is centered at about 45% from posterior to anterior and its length is 39 ± 0.58uro (3);
39-40um. The anterior ligament is 79 ± 3.06 (3); 76-82um in 152 length, and the posterior ligament is 56 ± 4.58um (3); 52-61um long.
Micropoints are found on the valve margin. They are
bluntly pointed and fairly numerous. A ventral flange is
only poorly developed (Fig. 47e).
This glochidium is easily distinguished by its shape.
It may well represent the end of an evolutionary line from
the nearly round glochidium of o. reflexa through the
progressively more depressed shells of C. stegaria and C.
aberti, to the extremely depressed valves of this species.
Surber (1912), Lefevre and Curtis (1912) and Ortmann (1912)
all give 190um x lOOum for length and height. This
glochidium is figured by Surber (1912, pi. 1, fig. 13),
Lefevre and Curtis (1912, fig. 1M) and Ortmann (1912, pi.
29, fig. 7).
Actinonaias Fischer and Crosse, 1894. Type species Unio
sapotalensis Lea, 1841
The glochidium of Actinonaias is subelliptical with
small dorsal alae, a coarsely malleated exterior valve surface and lanceolate micropoints located on the ventral rim of the valve and on a narrow ventral flange. Lea (1858) described the glochidium of Actinonaias liqamentina as,
Mpurse-shaped; dorsal line rather long, slightly outwardly curved and obtuse at the ends; side margins arcuate; basal margin [ventral margin] semicircular...'* 153 The adult shell is ovate to subelliptical, compressed
to moderately inflated and of medium size. The shells
generally lack a defined posterior ridge and sculpture.
However, if sculpture is present it is restricted to the
posterior slope and the umbo. The umbo is moderately
anterior and may have indistinct double-looped sculpture.
The marsupium is kidney shaped and consists of the posterior
two thirds of the outer gill. When charged with young the
ovisacs become enlarged and extend beyond the original gill
edge. The edge of the mantle is slightly thickened and
crenulated before the incurrent aperture.
Actinonaias pectorosa (Conrad, 1834)
Glochidium subelliptical, nearly symmetrical (Figs.
48a, 48b) with a length of 248 ± 4.58um (3); 244-253um, and
a height of 267 ± 5.77um (3); 260-270um. The dorsal margin
is straight and 144 ± 5.20um (3); 139-151um in length. The dorsal line may appear curved due to the extension of the umbo beyond the dorsal margin, but this glochidium and that
of A. ligamentina have straight dorsal margins. The
anterior and posterior margins are gently and evenly curved
and the ventral margin is semicircular. The exterior surface of the valve is malleated and pitted except at its margin where longitudinal ridges are found (Figs. 48c, 48d).
Dorsal alae are present (Figs. 48a, 48c) and about one 154 seventh the distance from dorsal to ventral. The sculpture
at the exterior surface of the valve is beaded (Fig. 48g).
The central ligament is about 46% from posterior to
anterior and its length is 60 ± 3.21um (3); 58-62um (Figs.
48b, 48f) . The anterior ligament is 48 ± 3.21um (3);
46-52um long, and the posterior ligament is 35 + 3.61um (3); 31-3 9um in length.
Micropoints are lanceolate and located on the ventral
margin and upon a narrow ventral flange (Fig. 48d, 48e).
The center of the ventral margin is slightly produced beyond
the base curvature of the margin to produce a small beak
(Figs. 48c, 48d). This beak-like area is densely covered with micropoints and probably facilitates attachment by digging deeply into host tissue, and/or helps induce encapsulation by ripping the tissues during attachment.
The glochidium of Actinonaias ligamentina carinata is nearly identical to that of A. pectorosa, except it is smaller. A single glochidium gave the following measurements: length, 220um; height, 243um; hinge length,
125um; anterior ligament length, 38um; central ligament
length, 57um; and posterior ligament length, 30um. Ortmann
(1912) gave the following length and height measurements for A. ligament ina and A. pectorosa: 220um x 240um for A. ligamentina, and 250um x 290um for Nephronajas pendix (= A. pectorosa fide Ortmann and Walker, 1922). The glochidium of
A. ligament ina is figured by Lea (1858, pi. 5, fig. 18), 155 Ortmann (1911, pi. 89, fig. 16) and Surber (1912, pi. 2, fig. 18). The glochidium of A. pectorosa is figured by
Ortmann (1912, pi. 19, fig. 12, as N. pendix).
Obovaria Rafinesgue, 1820. Type species Unio retusa
The glochidium of Obovaria is subelliptical, slightly asymmetric and higher than long. Dorsal alae are present and about twice as long as in Ptychobranchus. The dorsal margin is rather short and the ligaments are about equal in length.
The shell of the adult is variable, from subrotund to elongate oval. It is heavy and solid with well developed hinge teeth and lacks sculpture except at the umbo where indistinct concentric ridges may be found. The periostracum is brown, tan, olive to straw colored and the nacre is generally white but is usually purple in O. retusa. The marsupium is kidney shaped, consisting of the posterior two thirds of the outer gill and the ovisacs swell when charged so that the edges extend beyond the edge of the non-marsupial gill. The mantle edge just in front of the incurrent aperture has lamellar crenulations outlined in dark pigment running along the mantle margin. Ortmann
(1912) stated that, "this is another primitive type of the
Lampsilinae, leading, however, toward the more highly developed forms of the subfamily." 156 Obovaria retusa (Lamarck, 1819)
Glochidium subelliptical, slightly asymmetric (Figs.
49a, 49b) with a length of 221 ± 3.54um (2); 218-223um, and a height of 275 ± 4.24um (2); 272-278um. The dorsal margin is slightly curved and 117 + 2.08um (3); 115-119um in length. The posterior margin within the dorsal half of its length is rather straight sided and oblique to the dorsal line. At about midpoint the posterior margin gently curves and then straightens out to run more or less perpendicular to the dorsal line. The anterior margin is gently curved throughout its length to its maximum inflation near 70-80% from dorsal to ventral, and the ventral margin is semicircular in outline. The exterior surface of the valve is finely malleated and evenly pitted except at the valve margin. Dorsal alae are about the same length as those found in A. pectorosa. or about one seventh the height of the valve. The exterior surface of the valve is covered by beaded to loose looped sculpture (Fig. 49c).
The central ligament is centered at about 45% from posterior to anterior and is about 45um in length (Figs.
49b, 49d). The posterior ligament is about 26um long and the anterior ligament is about 38um long. Micropoints are lanceolate and arranged in broken vertical rows on the ventral rim of the valve and upon a narrow ventral flange.
Surber (1912) gave measurements for length and height of 240um x 295um while the figures from Ortmann (1912) are 1 5 7 220um x 270um. This rather wide discrepancy is not addressed by either author, and demonstrate the difficulty one finds when trying to determine the species of a glochidium based solely on size. In the case of O. retusa the moderately sized dorsal alae and valve shape will distinguish the glochidium from species other than those of
Obovaria. Its beaded to loose looped sculpture will distinguish this species from the other members of the genus. This glochidium is figured by Lea (1858, pi. 5, fig.
7), Surber (1912, pi. 3, fig. 47) and Ortmann (1912, pi. 19, fig. 9). Lea's figure shows the anterior and posterior margins evenly curved while Surber's figure shows the correct outline.
Obovaria olivaria (Rafinesque, 1820)
Glochidium subelliptical, slightly asymmetric (Figs.
49e, 49f) with a length of 202 ± 4.00um (3); 198-206um, and a height of 258 ± 3.Slum (3); 254-261um. The dorsal margin is slightly curved and 109 ± 5.81um (5); 104-118um long. As in O. retusa the posterior margin is mostly straight sided with a bend about half the distance from dorsal to ventral.
The anterior margin is gently curved and the ventral margin is semicircular. Dorsal alae are about the same size as those of O. retusa (one seventh as high as the valve) and the exterior surface is covered with loose looped sculpture
(Fig. 49g). 158 The central ligament is 39 + 5.03um (3); 34-44um in
length and is centered about 45% from posterior to anterior
(Figs. 49f, 49h). The posterior ligament is 27 + 1.53um
(3); 26-29um long, and the anterior ligament is 39 + 5.86um
(3); 3 2-43um long.
Micropoints, as in O. retusa, are lanceolate and located on the ventral rim and on a narrow ventral flange.
This glochidium is very similar to that of 0. retusa.
However, it is smaller and it has a different exterior valve sculpturing. This glochidium is figured by Surber (1912, pi. 2, fig. 25, as O. ellipsis = 0. olivaria fide Ortmann and Walker, 1922) and Ortmann (1912, pi. 19, fig. 11).
Surber gives length and height measurements of 210um x 26Sum and Ortmann (1912) records length and height measurements of
190um x 2 20um. Ortmann's figures are considerably smaller than Surber's and mine.
Obovaria subrotunda (Rafinesque, 1820)
Glochidium subelliptical (Figs. 50a, 50b) with a length of 177 ± 2.70um (5); 174-180um, and a height of 204 ± 5.63um
(5); 197-210um. The dorsal margin is slightly curved and 91
± 3.50um (6); 85-95um in length. The posterior margin is as in O. retusa and o. olivaria. however the ventral portion of the posterior margin is slightly more curved than was found in either of these species. The anterior margin is gently curved throughout its length with its maximum inflation 159 occurring about 60% from dorsal to ventral. The ventral margin is broadly rounded as in O. retusa and O. olivaria.
Dorsal alae are moderate in length, about the same length as found in the other species of Obovaria and exterior valve sculpture consists of fine loose loops (Fig. 50e).
The central ligament is 42 ± 2.12um (2); 40-43um in length and centered about 48% from posterior to anterior
(Figs. 50b, 50d). The anterior ligament is 27 ± 3.54um (2);
24-29um long, and the posterior ligament is 23 ± 2.83um (2);
21-25um in length.
Micropoints are of the usual shape and configuration for the genus. They are lanceolate and arranged in broken vertical rows on the ventral rim and on a short ventral flange (Fig. 50c). The unsculptured distal flange margin is narrow.
Surber (1915) described this glochidium as,
"semielliptical in shape; ventral margin rounded; hinge line long and slightly depressed near center; size medium." He suggests that this glochidium is intermediate between O. retusa and o. olivaria but that it differs from both by its smaller size. This study supports Surber's conclusion.
This glochidium shares moderately long dorsal alae with O. retusa, and moderately dense loose looped sculpture with O. olivaria. Ortmann (1912) gives 200um x 230um for length and height while Surber (1915) gives 170um x 215um. This glochidium is figured by Ortmann (1911, pi. 89, fig. 15, as 160 O. circulus - O. subrotunda fide Ortmann and Walker, 1922)
and Surber (1915, pi. 1, fig. 8, as O. circulus).
Obovaria iacksoniana (Frierson, 1912)
Glochidium subelliptical, almost symmetrical (Figs.
51a, 51b) with a length of 182 ± 5.74um (4); 175-I87um, and
a height of 23,6 ± 6.56um (4); 230-243um. The dorsal margin
is slightly curved and 95 ± 4.57um (4); 89-100um long.
Posterior and anterior margins are about equal, except that
the posterior margin is a little more produced as a result
of a larger angle of divergence. At about 50% from dorsal
to ventral the posterior margin curves ventrally and becomes
almost perpendicular to the dorsal margin and the anterior
margin becomes gently rounded. The exterior surface is
mostly smooth with just a few pits and very little
malleation, except at the umbo, and the exterior sculpture
is loose looped (Fig. 51c). Dorsal alae are about one
seventh as long as the height of the valve.
The central ligament is 42 + 0.71um (2); 41-42um in
length and centered 46% from posterior to anterior (Figs.
51b, 51d) . The anterior ligament is 29 ± 3.54um (2);
26-31um long, and the posterior ligament is 23 ± 2.83um (2);
21-25um long.
Micropoints are as in the other members of the genus.
They are located on the ventral rim of the valve and on a
short ventral flange (Figs. 51b, 51g). They are lanceolate 161 and arranged in incomplete vertical rows. No published
figures of this glochidium were found.
Obovaria unicolor (Lea, 18 45)
Glochidium subelliptical, almost symmetrical (Figs.
51e, 51f) with a length of 172 ± 4.36um (5); 168-180um, and
a height of 225 ± 5.86um (5); 218-234um. The dorsal line is
slightly curved and 90 ± 4.22um (5); 85-96um long. Anterior
and posterior margins are about equal, straight sided dorsally and slightly curved ventrally, as in O.
jacksoniana. The ventral margin is broadly rounded. The surface of the valve is mostly smooth with malleations at the umbo and there are few pits in the valve. Loose looped sculpture covers the exterior surface of the valve and dorsal alae are about one seventh valve height.
The central ligament is 3 2 ± 0.58um (3); 32-33um in length and centered about 45% from posterior to anterior.
The anterior ligament 3 5 ± 4.62um (3); 32-41um long, and the posterior ligament is 25 ± 2.65um (3); 23-28um long.
Micropoints are lanceolate, arranged in incomplete vertical rows and located on the ventral rim of the valve and on a short ventral flange (Figs. 51f, 51h).
This glochidium is essentially identical to that of O. jacksoniana. My measurements would indicate that the glochidium of O. unicolor is smaller than that of O. jacksoniana. but even here there is overlap. This 162 glochidium is figured by Ortmann (1912, pi. 19, fig. 10) who
gives length and height measurements of 160um x 210um.
Ellipsaria Rafinesque, 1820. Type species Obliquaria
lineolata
The glochidium of E. lineolata is much higher than long
with a very short hinge line and a broad ventral margin.
The outline of the glochidium is almost fan-like and the
lateral margins are widely gaping. Lateral valve gape in
this glochidium was observed by Ortmann (1912), who suggests
that this glochidium may be transitional toward the
glochidium of Potamilus.
The adult shell of E. lineolata is triangular, solid and rather compressed. The valve lacks sculpture except at the umbo where fine concentric to double-looped ridges may be found, and the periostracum is yellowish-green with broad dark green rays. The marsupium becomes large and distended when charged with young and consists of the posterior half of the outer demibranchs. The mantle in front of the incurrent aperture is slightly thickened and slightly folded. The soft parts are essentially like that of
Obovaria (Ortmann, 1912).
Ellipsaria lineolata (Rafinesque, 1820)
Glochidium subligulate, much higher than long (Figs.
52a, 52b) with a length of 237 ± 5.06um (7); 229-245um, and 1 6 3 a height of 321 ± 5.15um (7); 310-325um. The dorsal margin
is slightly curved and 91 + 3.55um (7); 87-96um long.
Anterior and posterior margins are more or less straight to
slightly incurved dorsally. At about 40% from dorsal to ventral the margins again become straight and slightly divergent. The point of maximum lateral inflation occurs at about 80% from dorsal to ventral. The ventral margin is broad, over twice the length of the hinge margin, but more narrowly curved than found in Obovaria. Actinonaias or
Ptvchobranchus. The external valve surface is finely malleated and evenly pitted except along the valve margins where pits and malleations are absent (Fig. 52c).
Vermiculate sculpture covers the exterior surface of the valve (Fig. 52 f) and the dorsal alae are very small and about at a 45° angle to the hinge.
The central ligament is 43 ± 8.42um (4); 3 5-51um long and is centered about 48% from posterior to anterior (Figs.
52b, 52e). The posterior ligament is 22 ± 1.63um (4);
20-24um long, and the anterior ligament is 26 ± 2.75um (4);
23-29um in length.
Micropoints are lanceolate and arranged in complete vertical rows on the ventral valve margin and on a wide ventral flange (Figs. 52b, 52d). They decrease in size distally and cover the proximal two thirds of the ventral flange, leaving a narrow unsculptured distal flange margin.
The ventral flange may be folded so that it forms small 164 hook-like points near the lateral margins of the flange
(Fig* 52c).
Lefevre and Curtis (1910), Surber (1912) and Ortmann
(1912) give the following measurements for length and
height: 230um x 310um, 230um x 330um , and 260um x 350um.
This glochidium can easily be distinguished from all others
by its fan-shaped outline, small dorsal alae, exterior valve
sculpture and its distinct hook-like folding of the ventral
flange. This glochidium is figured by Lea (1858, pi. 5,
fig. 6, as Unio securis = E. lineolata fide Ortmann and
Walker, 1922), Lefevre and Curtis (1910, fig. H, 1912, fig.
1H, as Plagiola securis), Ortmann (1911, pi. 89, fig. 17, as
P. securis) and Surber (1912, pi. 2, fig. 14, as P.
securis).
Leptodea Rafinesque, 1820. Type species Unio fragilis
The glochidium of Leptodea is small to medium sized,
subelliptical to almost subligulate and higher than long.
It has small dorsal alae, lamellate micropoints, lateral valve gape and a broadly to more narrowly rounded ventral margin. Exterior valve sculpture is loose looped and the valves are densely pitted.
The shell of the adult is moderate in size, rather thin, elliptical and compressed to inflated. A dorsal wing may be present. The periostracum may be dull and green to brown, but it is usually glossy straw colored. Nacre color 165 may be white, pink, blueish or purple. Ortmann (1912)
characterized the soft parts as essentially having the same
structure as Obovaria. The mantle in front of the incurrent
aperture is slightly thickened, crenulated but without
papillae or a mantle flap. The marsupia are kidney shaped,
swollen when charged, and consist of many ovisacs occupying
the posterior half of the outer gills.
Leptodea fraqilis (Rafinesque, 1820)
Glochidium subelliptical, very small (Figs. 53a, 53b)
with a length of 72 ± 0.58um (3); 72-73um, and a height of
82 ± 1.53um (3); 80-83um. The dorsal margin is straight and
33 ± 2.89um (3); 30-35um long. Anterior and posterior margins are about equally divergent dorsally and ventrally
curved. The ventral margin is broadly rounded and meets the
side margins at their point of maximum inflation, near 70%
from the dorsal margin. The exterior surface is only malleated near the umbo, however the valve surface is otherwise densely pitted except along the valve margin
(Figs. 53a, 53c) and where the adductor muscle inserts
(Figs. 53a, 53b). The exterior surface is lightly covered with loose looped valve sculpture (Fig. 53e) and dorsal alae
are rather small. Lateral valve gape is present but small
(Fig. 53c).
The central ligament is about Hum long and centered
about 45% from posterior to anterior. The posterior 166 ligament is 9 ± 1.41um (2); 8-10um in length, and the anterior ligament is 13 ± 2.12um (2); ll-14um long.
Micropoints are wide, lamellate plates arranged in complete vertical rows on the ventral valve margin and on a narrow ventral flange (Figs. 53b, 53c, 53d). The unsculptured distal flange margin is narrow.
This glochidium will not be confused with any other.
Its size, rather round subelliptical shape, small dorsal alae, and lamellate micropoints will distinguish it from all others. Lefevre and Curtis (1910, 1912), Surber (1912) and
Ortmann (1912) have given the following measurements for length and height: 7Sum x 8Sum, 70um x 95um, and 80um x
90um. This glochidium is figured by Lefevre and Curtis
(1910, fig. K, 1912, fig. IK, as Lampsilis gracilis = L. fraqilis fide Ortmann and Walker, 1922), Ortmann (1911, pi.
89, fig. 19, as Paraptera gracilis). Coker and Surber (1911, pi. 1, fig. 2, 2a, as L. gracilis) and Surber (1912, pi. 2, fig. 28, as L. gracilis).
Leptodea ochracea (Say, 1817)
Glochidium subelliptical to subligulate (Figs. 54a,
54b) with a length of 243 ± 1.95um (5); 241-246um and a height of 291 ± 1.92um (5); 289-294um. The dorsal margin is straight and short, 107 ± 3.90um (6); 102-110um in length.
Anterior and posterior margins are equal, more or less straight to slightly incurved dorsally, bending ventrally 167 about 50% from the dorsal margin and slightly curved to
their maximum inflation at about 80% from dorsal to ventral.
The ventral margin is gently and evenly curved throughout
its length. The exterior surface is malleated and pitted except along the valve margins where longitudinal ridges occur (Fig. 54a, 54c). Dorsal alae are small and lateral valve gape is moderate, larger than that of L. fraqilis but smaller than that of E. lineolata.
The central ligament is 43 ± 3.65um (4); 39-47um in length and centered about 48% from posterior to anterior
(Figs. 54b, 54d). The anterior ligament is 35 ± 2.22um (4);
32-37um long, and the posterior ligament is 31 ± 2.58um (4);
28-34um in length.
Micropoints are narrow lamellate plates arranged in complete vertical rows on the ventral flange and ventral valve rim (Figs. 54b, 54c, 54e) . They become smaller and more lanceolate distally and cover about four fifths of the surface of the flange. The unsculptured distal flange edge is very narrow.
The adult shell of L. ochracea is so similar to that of
Lampsilis cariosa that the adults are often confused. The glochidia are very dissimilar, however, and will be easily distinguished by valve outline, development of dorsal alae, presence of lateral valve gape and micropoint structure (see the glochidium of L. cariosa below). The glochidium of L. ochracea is figured by Porter and Horn (1981, fig.7). 168 This species is often included in the genus Lampsilis
primarily because the adult shell resembles that of other
members of that genus and because of the pronounced sexual
dimorphism in the shell (Simpson, 1900, 1914; Johnson, 1947,
1970; Burch, 1975; Clarke, 1981b). However, Morrison (1975)
found that mantle flaps, characteristic of the genus
Lampsilis, are absent in ochracea. Fuller and Bereza (1975)
suggest that this is not sufficient evidence to re-classify
ochracea and Porter and Horn (1981) conclude that because
the shape and size of the glochidium of ochracea is more
like that of cariosa than fraqilis, the species should
remain in Lampsilis. In fact, the glochidium of this
species does not ally ochracea with any species of Lampsilis
examined (see below). Since the anatomy of this species is
not that of Lampsilis and the glochidium, although larger,
is only closely allied to L. fraqilis. I must conclude with
Morrison (1975) that this species belongs in Leptodea.
Lastena Rafinesque, 1820. Type species Anodonta ohiensis
Rafinesque (1820) proposed the name Lastena and
included two species, Anodonta (Lastena) ohiensis and
Anodonta (Lastena) lata. During the description of lata he suggested that the species might be placed in a second
sub-genus, Hemistena. Since Hemistena is based solely on
lata, lata becomes the type of Hemistena by monotypy and no
longer need be considered here. 169 Herrmannsen (1847) designated A. ohiensis type of
Lastena but the confusion surrounding Rafinesque's
description of ohiensis has led to its uncertain status.
Utterback (1916) used A. (Lastena) ohiensis for A.
imbecillis, and Ortmann and Walker (1922) conclude that the
species is not imbecillis but that it might be the young of many species of Anodonta or even a synonym of Unio
laevissima Lea, 1830. LaRocque's (1964) translation of a portion of the description of A. ohiensis. "hinge with two transverse, obtuse wrinkles [hinge teeth], almost lamelliform..." however, clearly demonstrates that
Rafinesque had not described an Anodonta, since even young
Anodonta lack hinge teeth. His description of a thin, elliptical shell with olive colored periostracum, an angular posterior wing, and delicate lamellar hinge teeth describes the species that is more commonly cited as laevissima (see
Burch, 1975).
The name ohiensis is used here rather than ohioensis
(using the correct spelling of Ohio) since every indication is that Rafinesque (1820, 1831) intended to spell the name without the second "o". since Article 32c of the
International Code of Zoological Nomenclature (1985) only allows for the correction of unintentional misspellings, the name must remain as intended by Rafinesque.
The genus Lastena, as used here, contains three species; ohiensis, amphichaena and inflata. Glochidia of 170 the first two were examined and L. inf lata is included here
due to its similarity in adult shell structure with
ohiensis. The glochidium of Lastena is ligulate
(strap-shaped) or axe-head shaped. It has a straight, short
dorsal margin, a broadly rounded ventral margin and anterior
and posterior margins that are dorsally parallel and
crescent shaped ventrally. This glochidium is very small
with loose looped exterior valve sculpture, small dorsal
alae and lamellate micropoints. Unlike the glochidium of
Potamilus, the glochidium of Lastena does not possess
lanceolate hooks. In fact the species included in this
genus are separated from the genus Potamilus (defined by
Ortmann, 1912 as containing those species with axe-head
shaped glochidia) because other than shape, and here only in
superficial resemblance, the glochidia of Lastena are not at
all similar to those of Potamilus.
The shell of the adult is elliptical, compressed to moderately inflated, often with a posterior wing and
sometimes an anterior wing, thin lateral teeth, and oblique,
lamellate pseudocardinal teeth. The periostracum is olive
to tan and the nacre is pink to light purple. The shell and
soft parts are essentially like those of Leptodea.
Lastena ohiensis (Rafinesque, 1820)
Glochidium axe-head shaped, ligulate dorsally, becoming very broad ventrally (Fig. 55a) with a length of 12 3 ± 171 3.05um (3); 120-126um, and a height of 181 ± 6.03um (3);
175-187um. The dorsal margin is straight and very short, 45
± 3.42um (5); 42-50um in length. Anterior and posterior margins are equal; straight sided dorsally and crescent
shaped ventrally, and outwardly curved to their maximum
inflation at about 90% from dorsal to ventral. The exterior surface is smooth and exterior valve sculpture consists of loose loops (Fig. 55d). Dorsal alae are small and lateral valve gape is very large (Fig. 55b).
The central ligament is 19 ± 3.54um (2); 16-21um in length and centered about 50% from both lateral margins
(Fig. 55c). Anterior and posterior ligaments are equal; the anterior ligament is 14 ± 1.41um (2); 13-15um long, and the posterior ligament is 14 ± 0.71um (2); 13-14um long.
Micropoints are lamellate and located on the ventral rim and on a narrow ventral flange (Fig. 55e). Lanceolate hooks, characteristic of Potamilus, are absent (Figs. 55b,
55e) .
Lea (1858, 186 3) described this glochidium as wedge shaped with a hook-like process at each corner of the ventral margin. However, Coker and Surber (1911) reported that the spines or hooks were absent and Surber (1912) reported, "Glochidium without spines (?)." This glochidium can be distinguished from that of Potamilus by the absence of spines. They are further distinguished by micropoint structure, exterior valve sculpture and shape, especially 172 the roundness of the ventral margin. This glochidium shares
these characters with L. fraqilis. but can be distinguished
from this species by its axe-head shape. The glochidium of
L. ohiensis has been figured by Lea (1858, pi. 5, fig. 24),
Coker and Surber (1911, pi. 1, fig. 1, la), Surber (1912,
pi. 1, fig. 10) and Arey (1921, pi. 2, fig. 5, 6; 1924, pi.
1, fig. 3). Lea incorrectly figures the glochidium with
hooks while Coker and Surber (1911), Surber (1912) and Arey
(1921) do not. The shape of the glochidium is correctly drawn in each figure.
Lastena amphichaena (Frierson, 1898)
This glochidium is essentially identical to that of L. ohiensis. It is axe-head shaped (Fig. 52a) with a length of
112 + 1.41um (2); lll-113um, and a height of 171 + 0.71um
(2); 170-171um. This glochidium has a short dorsal margin and anterior ard posterior margins that are dorsally parallel becoming strongly curved ventrally. The length of the dorsal margin is 41 ± 0.71um (2); 40-41um. The anterior and posterior margins meet the broadly rounded ventral margin at the point of maximum lateral inflation which occurs at about 90% from dorsal to ventral. Dorsal alae are small and the exterior surface of the valve has loose looped sculpture (Fig. 52d).
The hinge of a single specimen gave the following measurements: anterior ligament, 13um; central ligament. 173 20um; posterior ligament, 14um (Fig. 52c). The central
ligament is centered about 49% from posterior to anterior.
Micropoints are lamellate, as in Leptodea fragilis and
Lastena ohiensis (Figs. 52b, 52e). They are arranged in vertical rows on the ventral valve margin and on a short ventral flange. Lanceolate hooks are absent.
This glochidium is almost identical with that of L. ohiensis but can be distinguished by its slightly more broadly rounded ventral margin. No published figures of this glochidium were found.
Potamilus Rafinesque, 1818. Type species Unio alatus
The glochidium of Potamilus is ligulate or axe-head shaped, very high for its length and with lanceolate hooks at the lateral margins of the ventral flange. Dorsal alae are present but small, vermiculate exterior valve sculpturing is present, lateral valve gape is extensive and micropoints are lanceolate to bluntly pyramidal.
The shell of the adult is thin to subsolid, ovate to subelliptical and inflated to compressed. A high dorsal wing may be present. The surface of the valve is unsculptured and the periostracum is generally dark but may be yellowish, especially when young. Nacre is usually purple and often very dark. Ortmann (1912) states, "this genus stands in all characters except the glochidia, by the side of Paraptera [= Leptodea]." 174 Potamilus alatus {Say, 1817)
Glochidium ligulate, axe-head shaped, much higher than
long (Figs. 53a, 53b) with a length of 216 + 9.15um (5);
206-227um, and a height of 378 ± 7.66um (5); 371-386um. The dorsal margin is straight although appearing slightly curved in exterior view due to the deep umbo cavity (Fig. 53c).
Anterior and posterior margins are equal, parallel sided for about 70% their length, then gently outwardly curved to their point of maximum inflation at about 95% from dorsal to ventral. The ventral margin is slightly curved. The adductor muscle scar is very rough, with numerous ridges, however pit density does not appear to be reduced. Dorsal alae are small (Fig. 53a), lateral valve gape is large (Fig.
53c) and the exterior surface is covered with vermiculate sculpture (Figs. 53e).
The length of the dorsal margin is less than half the total length of the valve at 102 ± 5.93um (5); 96-109um in length. The anterior ligament is 37 ± 2.12um (2); 35-38um in length, and the posterior ligament is 24 ± 7.07um (2);
19-29um long. The central ligament was 42um in the two specimens measured and was centered about 44% from posterior to anterior.
The lanceolate hooks of this species are long and attenuate (Figs. 53b, 53c, 53d). They are located at the lateral margins of the ventral flange and are slightly curved. Micropoints are arranged in complete vertical rows 175 on the ventral rim of the valve and on the rather wide
ventral flange. They are bluntly pointed and become
gradually smaller toward the distal edge of the flange.
They cover most of the flange leaving a narrow to absent unsculptured distal flange edge.
This glochidium is figured by Lea (1858, pi. 5, fig.
25), Lefevre and Curtis (1910, fig. D, 1912, fig. ID),
Ortmann (1911, pi. 89, fig. 18), Coker and Surber (1911, pi.
1, fig. 3), Surber (1912, pi. 1, fig. 8) and Utterback
(1915-6; figs. 9a, 9b). Length and height measurements are given by Lefevre and Curtis (1910, 1912), Surber (1912) and
Ortmann (1912); 230um x 410um, 220um x 380um, and 200um x
380um. This glochidium is similar to that of Potamilus purpuratus (described below) but can be distinguished from that species by its larger size and micropoint structure.
The glochidium of Potamilus capax is also similar to that of
P. alatus. although smaller (105um long x 185um high, Coker and Surber, 1911). If Coker and Surber (1911) have correctly figured this glochidium, its shape and the presence of lanceolate hooks would definitely ally this species with P. alatus rather than L. ohiensis. It should be noted that they correctly figured the glochidium of L. ohiensis (without hooks) and so it is likely that they also correctly figured the glochidium of P. capax. 176 Potamilus purpuratus (Lamarck, 1819)
Glochidium ligulate, axe-head shaped, much higher than
long (Figs. 54a, 54b) with a length of 195 ± 5.00um (3);
190-200um, and a height of 350 ± 4.93um (3); 347-356um. The
dorsal mergin is short and straight, 106 ± 3.87um (4);
100-109um long. Anterior and posterior margins are parallel
to about 80% from dorsal to ventral, becoming evenly curved
to the point of maximum lateral inflation at about 95% from
the dorsal margin. The ventral margin is only slightly
curved. The exterior surface of the valve is malleated and
pitted dorsally, ventrally smooth and there are fewer pits
in the area of the adductor muscle scar compared to the
surrounding valve area. Dorsal alae are small (Figs. 54a,
54c), the valve has a wide lateral gape, and the exterior
surface has vermiculate sculpture (Fig. 54e).
The central ligament is 39 ± 2.83um (2); 37-41um long
and centered about 46% from posterior to anterior (Fig.
54f). The anterior ligament is 37um in length, and the
posterior ligament is 29 ± 0.71um (2); 28-29um long.
Lanceolate hooks are located at the lateral margins of
the ventral flange (Figs. 54b, 54c). Micropoints are
arranged in complete vertical rows on the ventral rim of the
valve and on the wide ventral flange. They are bluntly pointed (Fig. 54d), become gradually smaller toward the distal edge of the flange and cover a large portion of the
flange leaving a narrow unsculptured distal edge. 177 This glochidium can be distinguished from that of P.
alatus by its micropoint structure and its size. This glochidium is figured by Lea (1874, pi. 21, fig. 13) and Surber (1915, pi. 1, fig. 5).
Ligumia Swainson, 1840. Type species Unio recta
The glochidium of Ligumia is very similar to that of
Actinonaias. The outline of the valve is subelliptical; the dorsal margin is nearly straight, the lateral margins are slightly rounded and the ventral margin is broadly rounded.
Micropoints are numerous, lanceolate, arranged in incomplete vertical rows and located on the valve margin and on a well developed ventral flange. Dorsal alae are long.
The shell of the adult is elongate elliptical, pointed posteriorly and unsculptured except at the umbo where double-looped sculpture is found. Hinge teeth are complete and the shell is usually greenish to black and sometimes has dark green rays. Sexual dimorphism is apparent in the shells and is expressed by the posterior inflation and ventral extension of the female shell. The marsupia are kidney shaped, distended when charged with young and limited to the posterior half of the outer demibranch. The mantle in front of the incurrent aperture has papillae that extend as far ventral and anterior as the ventral extension of the shell. 178 Ligumia recta (Lamarck, 1819)
Glochidium subelliptical (Figs. 58a, 58b) with a length
of 211 ± 6.02um (5); 205-219um, and a height of 260 ± 3.08um
(5); 257-265um. The dorsal margin is slightly curved and
109 ± 3.24um (7); 105-115um in length. Anterior and
posterior margins are equally curved and the valve is
symmetrical in outline. The exterior surface of the valve
is malleated and pitted except along the valve margin where
the shell is smooth. Dorsal alae are long and well developed, about one fifth the height of the valve (Figs.
58a, 58b, 58c). The fine sculpture of the exterior surface appears rough (Fig. 58e).
The central ligament is centered about 45% form posterior to anterior and is 38 ± 3.54um (2); 35-40um long.
The anterior ligament is 43 ± 2.83um (2); 41-45um in length, and the posterior ligament is 32 ± 2.83um (2); 30-34um long.
Micropoints are numerous, lanceolate, and are located on the ventral margin of the valve (Figs. 58d, 58e) and on a rather wide ventral flange (not figured). The center of the ventral margin appears almost beak-like, similar to that found in A. pectorosa (Fig. 58c).
This glochidium has the same valve outline as that of
A. pectorosa. However, the glochidium of L. recta can be distinguished from this glochidium by its larger size, broader ventral flange and longer dorsal alae. This glochidium is figured by Lea (1858, pi. 5, fig. 11), Lefevre 179 and Curtis (1910, fig. L, 1912, fig. 1L), Ortmann (1911, pi.
89, fig. 21), Surber (1912, pi. 2, fig. 17), Isom and Hudson
(1982, fig. 1) and Isom (1983, figs. la, lb).
Venustaconcha Thiele, 193 4. Type species Unio ellipsiformis
The glochidium of V. ellipsiformis is subelliptical
with moderately long dorsal alae, a broad ventral flange and
very fine loose looped exterior valve sculpture. Van der
Schalie (1963) stated that this glochidium, "compares very
favorably in outline and general appearance with that of
Actinonaias carinata."
The adult shell is moderate in size, elliptical in outline and produced posteriorly to give the posterior outline a somewhat snout-shaped margin. The umbo is located anterior of center and the periostracum is green to brown and ornamented with fine green rays. The adult shell resembles that of Villosa iris. The marsupium of the gravid female is composed of the posterior half of the outer demibranch which becomes distended when charged with young.
The mantle margin in front of the incurrent aperture has short to long papillae.
Venustaconcha ellipsiformis ellipsiformis (Conrad, 1834)
Glochidium subelliptical, symmetrical (Figs. 60a, 60b) with a length of 226 ± 2.94um (4); 223-230um, and a height of 285 ± 3.32um (4); 280-287um. The dorsal margin is 180 straight and 110 ± 2.48um (6); 107-114um in length.
Anterior and posterior margins are equally and gently curved
to their maximum inflation at about 70% from dorsal to
ventral and the exterior surface of the valve is finely
malleated near the umbo. Fine loose looped exterior valve
sculpture (Fig. 60e) is present and the adductor muscle scar
is indicated by numerous small ridges and reduced pitting
(Fig. 60f).
The central ligament is 40 ± 3.21um (3); 38-44um long
and centered 47% from posterior to anterior (Fig. 60g). The
posterior ligament is 30 ± 2.08um (3); 28-32um long, and the
anterior ligament is 36 ± 2.65um (3); 34-39um in length.
Micropoints are lanceolate and located on the ventral
rim of the valve and on a moderately wide ventral flange
(Figs. 60c, 60d). The micropoints are arranged in broken
vertical rows that extend about half the distance of the
flange, leaving a wide unsculptured distal flange margin.
This glochidium is identical to that of L. recta. except* it is larger. This glochidium is figured by Lea
(1858, pi. 5, fig. 9, as Unio spatulatus = V. ellipsiformis
fide Simpson, 1900) and van der Schalie (1963, pi. 1, center
left).
Villosa Frierson, 1927. Type species Unio villosus
The glochidium of Villosa is subelliptical to subspatulate. The dorsal margin is straight and the ventral 181 margin may be broadly to more gently curved. These glochidia have a wide ventral flange and broadly arched dorsal alae.
The adult shell is small to moderate sized, elliptical to ovate and lacks sculpture except at the umbo where double-looped ridges may be found. The shells are generally thin and hinge teeth are complete. The periostracum is yellowish to greenish, with fine green rays, and may be very dark. The soft parts are very similar to that of Ligumia or
Venustaconcha but the members of this genus are set apart by the large number of papillae projecting from the posterior mantle margin.
Villosa trabalis (Conrad, 1834)
Glochidium subelliptical, higher than long, with a short and straight dorsal margin, gently curved, almost equal lateral margins and a broadly rounded ventral margin
(Figs. 61a, 61b). The length of this glochidium is 214 ±
2.36um (4); 211-216um, and its height is 278 ± l.SOum (4);
277-280um. The dorsal margin is 96 ± 2.17um (5); 94-99um in length. The exterior iTalve surface is mostly smooth with relief occurring at the pits which are surrounded by smooth circular discs (Figs. 61e). Dorsal alae are moderate in length.
The central ligament is 33 ± 2.89um (3); 31-36um long and centered about 45% from posterior to anterior (Fig. 182 61b). The posterior ligament is 27 ± 1.53um (3); 25-28um
long, and the anterior ligament is 37 ± 2.31um (3); 36-40um in length.
Micropoints are lanceolate, numerous, and uhorganized.
They are found on the ventral rim of the valve and on the
distal half of a wide ventral flange {Figs. 61b, 61d). The
unsculptured distal flange margin is wide.
Surber (1912) gave 193um x 255um for the length and height of this glochidium, and Ortmann (1912) gave 220um x
270um. This glochidium is similar in shape, size and dorsal alae structure to Obovaria but it can be distinguished by
its rather wide ventral flange. The glochidium of Villosa perpurpurea (Lea, 1861) is virtually identical to that of V. trabalis. however it is smaller: length, 165um; height,
241um; hinge length, 88um. The glochidium of V. trabalis is figured by Surber (1912, pi. 3, fig. 40) and Ortmann (1912, pi. 20, fig. 4).
Villosa villosa (Wright, 1898)
Glochidium subelliptical (Fig. 62c) to subspatulate
(Figs. 62a, 62b, 62d) with a length of 245 ± 3.89um (7);
240-250um, and a height of 303 ± 4.26um (7); 296-308um. The dorsal margin is straight and 111 ± 3.65um (7); 105-116um in length. The usual shape of this glochidium (Figs. 62a, 62b,
62d) is characterized by a gently curved ventral margin and lateral margins that are oblique to the dorsal margin 183 dorsally and perpendicular ventrally. Dorsal alae are long
and extend about half the distance of the dorsal oblique
section of the lateral margins. The valve is finely malleated and densely pitted except along the margins.
Exterior sculpturing is rough but not quite beaded and may best be described as very fine pustules (Fig. 62g).
The central ligament is 40 + 3.54um (2); 37-42um long and centered about 49% from posterior to anterior (Figs.
62b, 62d). The anterior ligament is 38 ± 4.24um (2);
35-43um long, and the posterior ligament is about 33um long
(both specimens had identical posterior ligament lengths).
Micropoints are lanceolate and arranged in more or less complete vertical rows on the ventral flange and on the rim of the ventral margin of the valve (Figs. 62b, 62d, 62e,
62f). The micropoints become smaller from proximal to distal on the flange and cover about 75% of the flange surface. This leaves a narrow unsculptured distal flange margin.
The outline of the valve of this glochidium will distinguish it from the glochidia already described, but not from other members of this genus (see Villosa vibex and
Villosa iris iris below) and all members of the genus
Lampsilis. This appears to be the final change in glochidial shape within this linage. This glochidium is figured here for the first time. 184 Villosa vibex (Conrad, 1834)
Glochidium subspatulate (Figs. 63a, 6 3b) with a length of 230 ± 5.42um (8); 224-239um, and a height of 300 ± 4.17um
(8); 295-304um. The dorsal margin is straight and 110 ±
7.79um (8); 100-120um long. The lateral margins are straight and divergent dorsally, ventrally parallel, and the ventral margin is gently curved. Malleations and pits occur more or less uniformly over the surface of the valve and the fine sculpture of the exterior surface is rough (Figs. 63e,
63f). The membrane that covers the exterior surface is torn in Figure 63f and intact in Figure 63e. No adductor muscle scar was evident but just as in Alasmidonta marainata. the adductor muscle was found to insert on the interior surface of the valve rather than on the walls of the pits (Fig.
63c). Long dorsal alae like those in V. villosa were found.
The central ligament is 45 ± 0.71um (2); 44-4Sum long and centered about 48% from posterior to anterior. The anterior ligament is 31 + 2.12um (2); 29-32um in length, and the posterior ligament is 29 ± 0.71um (2) 28-29um long.
Micropoints are pyramidal and arranged in broken vertical rows on a wide ventral flange and on the ventral rim of the valve (Figs. 63b, 63e). They cover the proximal half of the ventral flange and leave a wide unsculptured distal flange margin.
This glochidium is figured by Lea (1858, pi. 5, fig. 4, as Unio rutilans = V. vibex fide Johnson, 1970; 1874, pi. 185 21, fig. 7, as Unio sudus = V. vibex fide Johnson, 1970).
The 1874 figure is closer to my figure of this glochidium
than the 1858 figure, except that the ventral half of the
figure is much to round. This glochidium is very close to that of v. villosa but it can be distinguished by its bluntly pyramidal micropoints and its wide unsculptured distal flange margin.
Villosa iris iris (Lea, 1829)
Glochidium subspatulate (Figs. 64a, 64b, 64c) with a length of 225 ± 5.84um (8); 217-232um, and a height of 296 ±
6.64um (8); 289-305um. The dorsal margin is straight and
113 ± 2.Slum (8); 107-115um in length. Anterior and posterior margins are about equal, dorsally divergent and ventrally parallel. The anterior margin may be slightly more rounded ventrally than the posterior margin and the ventral margin is gently curved. Dorsal alae are long, but only about half as long as the dorsal portion of the lateral margin*. The valve is malleated and pitted and the umbo is deeply folded (Figs. 64a, 64c, 64d). Concentric ridges extend from the umbo ventrally for a short distance, and loose looped sculpture covers the exterior surface of the valve (Fig. 64e).
The central ligament is 42 ± 0.58um (3); 41-42um long and centered 49% from posterior to anterior (Fig. 64b). The 186 anterior ligament is 39 ± l.OOum (3); 38-40um long, and the
posterior ligament is 33 ± 0.58um (3); 3 3-34um long.
Micropoints are lanceolate and arranged in broken rows
on the ventral rim of the valve and upon a wide ventral
flange (Figs. 64b, 64f). They cover the proximal half of
the flange leaving a wide unsculptured distal flange margin.
This glochidium can be distinguished from all other
subspatulate glochidia examined by its loose looped exterior
valve sculpture, its wide unsculptured distal flange boarder
and smaller dorsal alae. Surber (1912) gave length and height measurement of 240um x 300um for this glochidium and
Ortmann (1912) gave 220um x 280um. This glochidium is figured by Lea (1858, pi. 5, fig. 14, as Unio novi-eboraci =
V. iris fide Simpson, 1900), Ortmann (1911, pi. 89, fig. 20) and Surber (1912, pi. 3, fig. 46).
Lampsilis Rafinesque, 1820. Type species Unio ovatus
The glochidium of Lampsilis is subspatulate, higher than long, and possess rough exterior surface sculpturing.
The dorsal margin is straight, the ventral margin is gently curved and lateral margins diverge dorsally and run more or less parallel ventrally. Micropoints are lanceolate and located on the ventral rim of the valve and on a wide ventral flange. Dorsal alae are usually about half as long as the straight, divergent dorsal portion of the lateral margins. 187 The adult shell is ovate to elliptical and smooth
except at the umbo where double-looped sculpture may be
found. The periostracum is usually yellowish to green,
sometimes dark and generally with dark green rays. There is
pronounced sexual dimorphism in the shells and hinge teeth are complete. The anatomy is like that of Villosa except mantle flaps replace papillae in front of the incurrent aperture. The mantle flaps of Lampsilis are ribbon-like and probably serve to increase water flow over the developing young and attract the fish host. During release of the glochidia, the swollen marsupia are extended between the mantle flaps. When a fish, attracted by the motion, shape or color of the flaps, strikes, it receives a portion of the marsupial contents.
Lampsilis teres teres (Rafinesgue, 1820)
Glochidium subspatulate (Figs. 65a, 65b) with a length of 191 ± 1.87um (9); 189-194um, and a height of 258 ± 3.71um
(9); 255-265um. The dorsal margin is straight and 106 +
3.64um (14); 100-lllum long. Anterior and posterior margins are equal, dorsally divergent and parallel to slightly convergent ventrally. The ventral margin is gently curved.
The exterior valve surface is malleated and pitted and the exterior surface is rough (Fig. 65d). Dorsal alae are about half as long as the divergent portion of the lateral mar g i n s . 188 The central ligament is 34 ± 4.09um (6); 27-39um long and centered about 45% from posterior to anterior. The anterior ligament is 46 ± 5.08um (6); 41-54um long, and the posterior ligament is 31 ± 0.82um (6); 30-‘32um in length.
Micropoints are lanceolate (deformed in Fig. 65e), sharply pointed and restricted to the proximal half of the ventral flange and the ventral rim of the valve (Fig. 65e).
The ventral flange is wide (Figs. 65b, 65e) as is the unsculptured distal flange margin.
Surber figures this glochidium (1912, pi. 2, fig. 22, as L. fallaciosa - L. teres fide Johnson, 1972) and gives length and height measurements of 200um x 240um. This glochidium is much smaller than any other recorded for
Lampsilis. except L. t. anodontoides (see below).
Lampsilis teres anodontoides
Glochidium subspatulate (Figs. 66a, 66b) with a length of 199 + 7.19um (7); 187-207um, and a height of 251 ± 2.87um
(7); 249-255um. The dorsal margin is straight and 111 ±
4.42um (9); 105-118um long. The outline of the valve is like that of L. t. teres; lateral margins are dorsally divergent, becoming parallel to convergent ventrally and the ventral margin is gently curved. The exterior surface of the valve is malleated, especially near the umbo, and pits are numerous. As in L. t. teres, dorsal alae are about half as long as the dorsal portion of the lateral margins. The 189 exterior surface appears rough under high magnification
(Fig. 66d).
The central ligament is 3 8 ± 2.45um (5); 36-42um long
and centered about 45% form the posterior margin (Figs. 66b,
66c). The anterior ligament is 46 ± 2.88um (5); 44-50um
long, and the posterior ligament is 31 ± 1.14um (5); 30-33um
long.
Micropoints are lanceolate and located on the ventral
rim of the valve and on a wide ventral flange (Figs. 66b,
66e). They are arranged in incomplete vertical rows and the
unsculptured distal flange margin is moderate in length.
This glochidium is identical to that of L. t. teres.
Surber (1912) gives length and height measurements of 185um x 210um for this glochidium and Ortmann (1912) gives 200um x
260um. Surber’s measurements seem too small even for this glochidium and his figure (1912, pi. 2, fig. 21) shows the ventral margin as semicircular rather than gently curved.
These discrepancies suggest that his material was not mature. This glochidium is also figured by Lea (1858, pi.
5, fig. 2) and Ortmann (1912, pi. 20, fig. 9). Lea's figure is much closer to Ortmann1s and mine than Surber's figure.
Lampsilis radiata radiata (Gmelin, 1791)
Glochidium subspatulate (Figs. 67a, 67b) with a length of 255 ± 4.43um (4); 250-260um, and a height of 303 ± 6.58um
(4); 295-311um. The dorsal margin is straight and 125 ± 190 3.78um (4); 121-129um in length. The lateral margins are
dorsally divergent and ventrally parallel, and the ventral margin is gently curved. Dorsal alae are long and the fine
structure of the exterior surface of the valve is rough
(Fig. 67d). The exterior surface is finely malleated and the valve at the umbo is deeply folded.
The central ligament is 46 ± l.OOum (3); 45-47um long and centered about 42% from posterior to anterior (Figs.
67b, 67c). The anterior ligament is 48 ± 2.08um (3);
46-50um long, and the posterior ligament is 29 ± 2.52um (3); 27-3 2um long.
Micropoints are lanceolate, located on the rim of the ventral margin and on a wide ventral flange (Figs. 67b,
67d) . They are arranged in broken vertical rows and cover the proximal half of the ventral flange. The unsculptured distal flange margin is wide.
Morphometries from the subspecies L. r. luteola are: length, 231 ± 2.39um (8); 227-235um; height, 285 + 6.63um
(8); 260-295um; hinge length, 115 ± 5.23um (12); 107-123um; anterior ligament length, 39 ± 1.94um (6); 37-42um; central ligament length, 42 ± 2.58um (6); 40-46um; posterior ligament length, 36 ± 3.39um (6); 32-40um.
Surber (1912) and Ortmann (1912) give length and height measurements for the glochidium of L. r. luteola; Ortmann's figures are 230um x 280um (almost identical to mine) and
Surber gives 250um x 290um (almost the same as my 191 measurements for L. r. radiata) . This species is as far
ranging as Anodonta qrandis and appears to have just as wide
a range in glochidial size. The glochidium of L. r. radiata
is figured by Lea (18 58, pi. 5, fig. 20) and Calloway and
Turner (1979, pi. 3, figs. 2, 4, 6, 9). The glochidium of
L. r. luteola is figured by Lea (18 58, pi. 5, fig. 10),
Surber (1912, pi. 2, fig. 15) and Arey (1921, pi. 2, fig. 3, 4; 1924, pi. 1, fig. 1).
Lampsilis abrupta (Say, 1831)
Glochidium subspatulate (Figs. 68a, 68b) with a length of 210 + 2.66um (6); 207-214um, and a height of 254 ± 3.13um
(6); 251-259um. The dorsal margin is straight and 102 ±
5.62um (7); 96-112um in length. The exterior surface is finely malleated and wrinkled near the umbo. The fine structure of the exterior surface of the valve is rough
(Fig. 68e). Pits are few in number and more or less evenly distributed throughout the valve. Dorsal alae are long and extend about one fifth the height of the valve. The hinge of a single specimen had the following ligament lengths: anterior ligament, 46um; central ligament, 38um; posterior ligament, 27um. The central ligament is centered about 44% from posterior to anterior (Fig. 68f).
Micropoints are lanceolate and arranged in broken vertical rows on a wide ventral flange and on the rim of the ventral margin (Figs. 68b, 68c, 68d). They cover the 192 proximal half of the ventral flange, leaving a wide
unsculptured distal flange margin.
Lea (1863) stated that this glochidium is, "almost
exactly the same with multiradiatus." [= Lampsilis fasciola
fide Ortmann and Walker, 1922], however the glochidium of L.
abrupta is much smaller than that of L. fasciola. Ortmann
(1912) gives length and height measurements of 190um x 210um
and 200um x 250um for the glochidium of L. orbiculata (= L.
abrupta fide Stansbery et al., 1985). My figures are nearer
his second set of measurements and the glochidia were all
about the same size. There is often differential maturation
of glochidia and Ortmann*s smaller individuals may have been
immature. This glochidium is figured by Ortmann (1911, pi.
89, fig. 22, as L. orbiculata).
Lampsilis hiqqinsi (Lea, 1857)
Glochidium subspatulate (Figs. 69a, 69b) with a length
of 216 ± 2.12um (2); 214-217um, and a height of 256 ± 2.12um
(2); 254-257um. The dorsal margin is straight and 111 ±
4.72um (4); 108-118um in length. Anterior and posterior margins are dorsally divergent and subparallel ventrally.
The ventral margin is gently curved. The surface of the
valve is finely malleated and concentric ridges occur near
the umbo. Dorsal alae are strongly curved and extend about half the distance of the dorsally divergent portions of the 193 lateral margins (Figs. 69a, 69c), and the fine structure of
the exterior surface is rough (Fig. 69e).
The central ligament is 43 ± 5.66um (2); 39-47um long
and centered about 47% from posterior to anterior (Fig.
69f). The anterior ligament is 39 ± 1.41um (2); 38-40um in
length, and the posterior ligament is about 31um long.
Micropoints are lanceolate and arranged in incomplete rows on the ventral flange and on the rim of the ventral margin (Fig. 69d). The micropoints decrease in size distally and cover about three quarters of the flange surface. The unsculptured distal flange margin is moderate in width.
Waller et al. (1988) give almost identical morphometric data for this glochidium. They also found that the glochidium of L. recta has similar morphometries. They suggest however, that the glochidia are also the same shape and can be distinguished only by the extent of the development of dorsal alae and placement of the central hinge ligament. Their conclusion regarding the shape of the glochidia was based on their inability to distinguish any differences in shape upon overlaying light microscopy transparencies. I found that the glochidium of L. recta can best be described as subelliptical; with a rounded ventral boarder and equally curved lateral margins (similar to that of A. pectorosa), while the glochidium of L. hiqqinsi is subspatulate; with a gently curved ventral margin and 194 lateral margins that are dorsally divergent and ventrally parallel. The anterior margin of L. higginsi is slightly more rounded than the posterior margin and the margins are clearly not equal. These differences are subtle, however they do distinguish these glochidia. Waller et al. also state that the central ligament is more posterior in L. recta than L. higginsi. although they do not give data to support their claim. I found that the ligament position of
L. higginsi was about 47% from posterior to anterior and that the midpoint of the central ligament of L. recta was about 45%. Both are identified here as having a central ligament position but neither can be described as more central. We agree, however, concerning the development of dorsal alae. They found that dorsal alae (their dorsal ridges) were more developed in L. higginsi than in L. recta.
That difference is demonstrated in my figures (compare Figs.
59c with 69c). This glochidium is figured by Waller et al.
(1988, figs. 2, 4), who give length, height and hinge length measurements of 215um x 259um x llOum.
Lampsilis ovata (Say, 1817)
Glochidium broadly subspatulate (Figs. 70a, 70b) with a length of about 232um and a height of 274 ± 3.54um (2);
271-276um. The dorsal margin is straight and 116 ± 2.58um
(4); 113-119um in length. The dorsal portions of the lateral margins are strongly divergent, the ventral portions 195 of these margins are subparallel, and the anterior margin is slightly curved. Dorsal alae extend about three quarters the length of the dorsal divergent portion of the lateral margins and the ventral margin is gently curved. The fine structure of the exterior surface of the valve is rough (Fig. 70e).
The central ligament is 44 ± 0.71um (2); 43-44um long and centered about 49% from posterior to anterior (Figs.
70d, 70f). The anterior ligament is 40 ± 0.71um (2);
39-40um long, and the posterior ligament is 35 ± 0.71um (2);
34-35um in length.
Micropoints are bluntly pyramidal to lanceolate and arranged in broken vertical rows on the ventral flange and upon the rim of the ventral margin (Fig. 70c). They cover three quarters of the ventral flange leaving a moderately wide unsculptured distal flange margin.
This glochidium is distinguished from those previously described by its broadly subspatulate shape. However, this shape is also found in the glochidia of the other members of the L. ovata complex (ie, L. ventricosa, L. satura and L. ornata) . Relative size may be the only way to distinguish them (see below). It should be noted, however, that Waller et al. (1988) found relative size to be an unreliable means of determining identity. This glochidium is figured by Lea
(1858, pi. 5, fig. 15) and Isom (1983, fig. lc). 196 Morphometries from Lampsilis satura are: length, 222 ±
2.12um (2); 220-223um; height, 269 ± 0.71um (2); 268-269um;
hinge length, 115 ± 1.82um (4); 113-117um; anterior ligament
length, 43 ± 0.71um (2); 42-43um; central ligament length,
40um; posterior ligament length, 34 ± 1.41um (2); 33-35um.
The position of the central ligament is about 48% from posterior to anterior.
Morphometries from Lampsilis ornata are: length, 202 ±
3.21um (3); 198-204um; height, 258 ± 1.53um (3); 257-260um;
hinge length, 98 ± 2.08um (3); 96-100um. A single specimen gave the following ligament lengths: anterior ligament,
38um; central ligament, 33um; posterior ligament, 29um. The midpoint of the central ligament is about 46% from posterior to anterior.
Lampsilis ventricosa (Barnes, 1823)
Glochidium broadly subspatulate (Figs. 71a, 71b) with a length of 249 ± 4.46um (18); 240-255um, and a height of 283
± 6.30um (18); 274-292um. The dorsal margin is straight and
111 ± 4.06um (21); 104-118um in length. The shape of this glochidium is very much like that of L. ovata. The straight dorsal portion of the lateral margin is strongly divergent, the ventral portion of the lateral margin is almost parallel and the ventral margin is gently curved. Dorsal alae are long and strongly arched (Figs. 71a, 71c) and the fine 197 structure of the exterior valve sculpture is rough (Fig. 71f) .
The central ligament is 39 ± 1.98um (8); 37-42um in length and centered about 47% from posterior to anterior
(Figs. 71b, 71g). One female produced glochidia with a more posterior central ligament (43%) while another produced glochidia with a more anterior central ligament (50%). The anterior ligament is 44 + 4.82um (8); 38-50um long, and the posterior ligament is 32 ± 1.41um (8); 29-33um in length.
Micropoints are lanceolate to bluntly pyramidal and are arranged in broken vertical rows on a wide ventral flange and on the rim of the ventral margin (Figs. 71b, 71d, 71e).
They cover about 75% of the flange and leave a moderately wide unsculptured distal flange margin.
The glochidium of L. ventricosa is longer and higher than that of L. ovata. but both species have about the same hinge length. This glochidium is figured by Lea (1858, pi.
5, fig. 13, as Unio occidens = L. ventricosa fide Johnson,
1970), Ortmann (1911, pi. 89, fig. 23), Surber (1912, pi. 2, fig. 24) and Waller et al. (1988, figs. 5, 6). Surber gives length and height measurements of 200um x 250um for this glochidium, Ortmann (1912) gives 250um x 290um and Waller et al. give 216um x 257um. My measurements are 249um x 283um.
Waller et al. and Surber collected their material from the
Mississippi River while Ortmann’s and my material came from smaller streams. It is possible that this species has a 198 large river form and small river form of glochidium. The
presence of small and large river forms in adult shells have
been demonstrated (see Stansbery, 198 3, for a discussion of the forms of Fusconaia flava).
Lampsilis reeviana brevicula (call, 1887)
Glochidium broadly subspatulate (Figs. 72a, 72b) with a
length of 235 + 6.05um (8); 230-245um, and a height of 290 ±
4.37um (8); 286-297um. The dorsal margin is straight and
119 ± 4.50um (9); 113-127um long. Lateral margins are straight and strongly divergent dorsally and subparallel ventrally. The anterior margin is slightly more curved ventrally than the posterior margin and the ventral margin is gently curved throughout its length. Dorsal alae are about as long as the divergent dorsal portion of the lateral margins and the fine structure of the exterior surface is rough (Fig. 72d).
The central ligament is 43 ± 4.39um (5); 37-48um in length and centered about 47% from posterior to anterior
(Figs. 72b. 72c). The anterior ligament is 4 3 ± 5.45um (5);
38-50um long and the posterior ligament is 34 ± 2.19um (5);
3 2-36um in length.
Micropoints are lanceolate and arranged in broken vertical rows on the ventral rim of the valve and on a wide ventral flange (Figs. 72b, 72e). They cover the proximal 199 half of the ventral flange and leave a wide unsculptured
distal flange margin.
This glochidium is figured by Surber (1915, pi. 1, fig.
14). He gives measurements for length and height of 230um x 290um for this glochidium.
Lampsilis crocata (Lea, 1841)
Glochidium narrowly subspatulate (Figs. 73a, 7 3b) with
a length of 242 ± 6.2 3um (8); 235-249um, and a height of 293
± 5.03um (8); 287-303um. The dorsal margin is straight and
118 ± 4.81um (8); 110-125um in length. Lateral margins are weakly divergent dorsally and ventrally subparallel. The ventral margin is evenly and broadly curved, dorsal alae are long and strongly arched (Figs. 73a, 73c) and the fine structure of the exterior surface of the valve is rough
(Fig. 7 3 e ).
The central ligament is 54 ± 2.83um (2); 52-56um long and centered about 46% from posterior to anterior (Fig.
73b). » The anterior ligament is 38 ± 2.12um (2); 36-39um long, and the posterior ligament is about 32um long.
Micropoints are bluntly lanceolate and cover about 75% of the ventral flange (Figs. 73b, 73d, 73f). They are arranged in broken vertical rows on the ventral flange and on the rim of the ventral margin and they remain about equal in length from proximal to distal. The unsculptured distal flange margin is narrow. 200 The shape of this glochidium is like that of L. teres,
however it is much larger than L. teres. No published
figure of this glochidium was found.
Lampsilis cariosa (Say, 1817)
Glochidium narrowly subspatulate (Fig. 74a) with a
length of about 241um, a height of about 314um and a hinge
length of about 109um. The dorsal margin is straight, the
ventral margin is evenly and broadly curved and the lateral margins are about equally divergent dorsally and ventrally
parallel. Dorsal alae are long and the fine structure of
the exterior surface of the valve is rough (Fig. 74c). The valve is pitted except along the margins of the valve and pitting is reduced in the adductor muscle scar (Fig. 74b).
The umbo is deeply folded and the center of numerous concentric ridges. Hinge ligaments were not seen.
Micropoints are lanceolate and restricted to the proximal half of the ventral flange and upon the rim of the ventral valve margin. They are arranged in broken vertical rows and the unsculptured distal edge of the ventral flange is wide.
I was unable to clean these glochidia so only a very few micrographs were taken. However, it is clear that this glochidium is very different from that of Leptodea ochracea.
The long dorsal alae, lanceolate micropoints and rough exterior valve sculpture place this glochidium firmly in 201 Lampsilis. whereas the small dorsal alae, lamellate
micropoints, loose looped exterior sculpture and lateral
valve gape separate the glochidium of Leptodea ochracea from
Lampsilis. No published figure of this glochidium was found.
Lampsilis fasciola Rafinesque, 1820
Glochidium narrowly subspatulate (Figs. 75a, 75b) with
a length of 247 + 4.47um (5); 240-250um, and a height of 290
± 3.08um (5); 287-295um. The dorsal margin is straight and
110 ± 2.95um (5); 107-115um in length. The posterior margin
is strongly divergent from the dorsal margin for about half
its length. Near its midpoint, the posterior margin bends ventrally and straightens out to run more or less perpendicular to the hinge. The anterior margin diverges
from the dorsal margin at a lesser angle and is straight for about three quarters of its length before it curves continuously to the ventral margin. The ventral margin is gently and evenly curved. Dorsal alae are long with a strong arch (Figs. 75a, 75c) and the fine structure of the exterior surface of the valve is rough (Fig. 75e).
The central ligament is about 44um long and centered about 48% from the posterior margins. The anterior ligament is about 38um long and the posterior ligament is about 33um long. Figure 75f is an enlargement of the hinge of Figure
75b. Only one glochidium demonstrated a clear hinge. 202 Micropoints are lanceolate and are arranged in broken
vertical rows on the ventral rim of the valve and on a wide
ventral flange (Fig. 75d). The micropoints decrease in size
distally on the flange and cover about three quarters of its
proximal surface. This leaves a narrow ur.sculptured distal
flange margin.
The glochidium of L. fasciola is figured by Lea (1858, pi. 5, fig. 17, as Unio multiradiatus - L. fasciola fide
Ortmann and Walker, 192 2) and Surber (1915, pi. 1, fig. 2, as L. multiradiatus). This glochidium is not much different from the other narrowly subspatulate glochidia except that the anterior margin is slightly more rounded. In this regard this glochidium resembles that of Obovaria but it
* - - will not be confused with Obovaria because of it posterior margin, wide ventral flange and rough exterior valve sculpture. The glochidium of Obovaria has a curved posterior margin, narrow ventral flange and loose looped exterior valve sculpture.
Epioblasma Rafinesque, 1831. Type species Truncilla triguetra
The glochidium of Epioblasma is depressed subelliptical with a straight dorsal margin, narrowly rounded lateral margins and a broadly rounded ventral margin. Micropoints are irregular and usually arranged in horizontal rows on the ventral flange. Supernumerary hooks are unique to the 203 members of this genus. These small lanceolate to
triangulate hooks are found in the distal, generally unsculptured, region of the ventral flange.
The adult shell is small and sexual dimorphism is pronounced. The posterior margin of the female shell is generally very much inflated and projects beyond the normal margin of the valve. As in all lampsiline species the marsupium is restricted to a portion of the outer gill; however, unique to this genus is the modification of the mantle well before the incurrent aperture into a flap that extends medially so as to create a posterior chamber. This flap may be brightly colored and appears to increase water supply to the young but may also function to attract the fish host.
Epioblasma triouetra (Rafinesque, 1820)
Glochidium depressed subelliptical (Figs. 76a, 76b,
76c) with a length of 214 + 3.54um (5); 208-217um, and a height of 211 ± 4.09um (5); 205-214um. The dorsal margin is straight and 152 ± 3.05um (5),- 149-156um in length. Lateral margins are equally and gently curved and the ventral margin is broadly curved. The exterior surface is sparsely malleated and pits are few. The glochidium has loose looped exterior valve sculpture and dorsal alae are absent (Fig.
76a) . 204 The central ligament is 50 ± 2.89um (3); 48-53um in
length and centered about 44% from posterior to anterior
(Figs. 76b, 76c). The anterior ligament is 60 ± 4.Slum (3);
56-65um long, and the posterior ligament is 43 + 4.73um (3);
39-48um in length.
Micropoints are blunt and irregular in shape (Figs.
76d, 76e). The ventral flange is narrow and the distal unsculptured flange edge is wide (Figs. 76b, 76c, 76d, 76e).
Supernumerary hooks are triangular extensions of the unsculptured portion of the flange.
This glochidium is figured by Lea (1858, pi. 5, fig.
19, as Unio triangularis = E. triquetra Ortmann and Walker,
1922) and Ortmann (1911, pi. 89, fig. 24). Ortmann (1919) notes that Lea's figure is incorrect and gives length and height measurements of 210um x 210um (Ortmann, 1912). Lea's figure does not show the morphological depression of the valve.
Epioblasma brevidens (Lea, 1831)
Glochidium depressed subelliptical (Figs. 77a, 77b) with a length of 216 ± 3.Hum (4); 213-220um, and a height of 210 ± 4.24um (4); 205-214um. The dorsal margin is straight and 147 ± 5.06um (4); 141-153um long. The lateral margins are equally and evenly curved and the ventral margin is broadly curved. The exterior surface is sparsely malleated and pits are few. Valve pitting is reduced in the 205 adductor muscle scar, however irregular ridges, probably used to increase surface area for attachment of the large adductor muscle, are found within the muscle scar (Figs.
77b, 77d) . The fine structure of the exterior surface of the valve is rough (Fig. 77e) and dorsal alae are absent.
The central ligament is 49 ± 0.71um (2); 48-49um in length and centered about 46% from the posterior margin
(Fig. 77f). The anterior ligament is 51 ± 2.12um (2);
49-52um in length, and the posterior ligament is 44 ± 4.24um
(2),* 41-47um long.
Micropoints are small, triangular, and arranged in horizontal rows on the ventral flange and on the ventral rim of the valve (Fig. 77c). Supernumerary hooks are triangular
(Fig. 77b) to lanceolate (Fig. 77c) and the unsculptured distal margin of the ventral flange is narrow.
This glochidium is similar to that of E. triquetra.
They are about the same shape and size, have similar micropoints and central ligament positions. However, the glochidium of E. brevidens has rough exterior valve sculpture whereas the glochidium of E. triquetra has loose looped exterior valve sculpture.
Epioblasma capsaeformis (Lea, 183 4)
Glochidium depressed subelliptical (Figs. 78a, 78b,
78e) with a length of 246 ± 3.88um (8); 240-252um, and a height of 234 ± 4.34um (8); 226-238um. The dorsal margin is 206 straight and 162 ± 6.33am (8); 154-173um long. Lateral margins are about equal and gently curved (Figs. 78a, 78b) to more broadly curved (Fig. 78e). The ventral margin is broadly curved, dorsal alae are absent and loose looped exterior valve sculpture covers the valve (Fig. 78f). The adductor muscle scar is large with only a few pits and with numerous small ridges (Figs. 78b, 78e). As was demonstrated for other glochidia, there is a membrane covering the exterior surface of the valve (Fig. 78a).
The midpoint of the central ligament is about 46% from posterior to anterior and its length is 57 ± 3.43um (6);
51-60um (Figs. 78b, 78e, 78g). The anterior ligament is 59
± 4.45um (6); 52-64um long, and the posterior ligament is 47
± 5.89um (6); 40-57um in length.
Micropoints are blunt and irregular (Fig. 78c). They are arranged in broken horizontal rows on a narrow ventral flange. Near the proximal boarder the micropoints coalesce and form broken ridges. The distal unsculptured margin is narrow, and attenuate supernumerary hooks are found in the otherwise unsculptured distal flange margin (Fig. 78d).
This glochidium is slightly larger than that of E. triquetra or E. brevidens but it is otherwise very similar.
No published figures of this glochidium were found. 207 Epioblasma torulosa ranqiana (Lea, 1839)
Glochidium depressed subelliptical (Figs. 79a, 79b,
79c) with a length of 249 ± 7.34um (8); 238-258um, and a
height of 224 ± 9.34um (8); 210-238um. The dorsal margin is
straight and 170 ± 6.30um (8); 160-188um in length. The
lateral margins and ventral margin are about equally rounded
and the shape of this glochidium approaches that of
Obliguaria reflexa (subrotund). Dorsal alae are absent and
the surface sculpturing is loose looped (Fig. 79f).
The central ligament is 57 ± 3.21um (3); 53-59um long
and centered about 46% from posterior to anterior (Fig. 79b.
79c, 79d). The anterior ligament is 68 ± 8.62um (3);
60-77um long, and the posterior ligament is 52 ± 5.21um (3);
50-55um in length.
Micropoints are blunt and located on a narrow ventral flange and on the ventral rim of the valve (Fig. 79e). They cover about 50% of the flange and leave a wide unsculptured distal flange margin. Supernumerary hooks are present as triangular extensions of this unsculptured area of the flange.
This glochidium can be distinguished by its extreme morphological depression. Otherwise it is very similar to the other members of this genus. This glochidium is figured by Lea (1858, pi. 5, fig. 21, as Unio per plexus = E. ranqiana fide Ortmann and Walker, 1922), who gives length and height measurements of 224um x 240um. Lea's figure is 208 correctly drawn so it must be assumed that his valve length equals my valve height and that his valve height equals my valve length. His measurements would then agree with mine and Ortmann's (1912); 260um x 230um. Figure 42. Glochidium of Ptychobranchus fasciolaris; a. exterior valve, MAH:640.1, bar length = 25um; b. interior valve, MAH:640.1, bar length = 25um; c. lateral view, MAH:640.1, bar length = 35um; d. ventral valve edge, MAH: 651, bar length = 5um,- e. exterior valve sculpture, MAH:651, bar length = lum. Figure 43. Glochidium of Ptychobranchus occidentalis (a-d) and Ptychobranchus qreeni (e-h); a exterior valve OSUM:45361.17, bar length 35um; b. interior valve, OSUM:45361.14, bar length 35um; c. exterior valve sculpture, OSUM:45361.17, bar length = lum; d. hing e, OSUM:45361.17, bar length = 15um; e. exterior valv e, OSUM:19025.2, bar length 35um; f. interior va l v e , OSUM:19025.2, bar length 35um; g. exterior valve sculpture, OSUM:19025.2, bar length = lum; h. micropoints, OSUM:19025.2, bar length = 2um,
210 211
c
Figure 43. Glochidium of Ptychobranchus occidentalis (a-d) and Ptychobranchus greeni (e-h). Figure 44. Glochidium of Ptychobranchus subtentum OSUM:43156.5; a. exterior valve, bar length = 35um; b. interior valve, bar length = 35um; c. exterior valve sculpture, bar length = lum; d. hinge, bar length = 20um; c. micropoints, bar length = 5um; f. interior valve pitting, bar length = lOum. 2 1 3
Figure 45. Glochidium of Obliquaria reflexa. OSUM:54361. 1 ; a. exterior valve, bar length = 35um; b. interior valve, bar length = 3 Sum; c. ventral view, bar length = 2 Sum; d. micropoints, bar length = 7um. Figure 46. Glochidium of Cyprogenia stegaria (a-d) OSUM:6298.21, and Cyprogenia aberti (e-i) OSUM:48067; a. exterior valve, bar length = 30um; b. interior valve, bar length = 30um; c. exterior valve sculpture, bar length = 2um; d. hinge, bar length = 20umj e. exterior valve, bar length = 30um? f. interior valve, bar length = 30um; g. micropoints, bar length = 5um; h. micropoints, bar length = Sum; i. hinge, bar length = 20um.
214 215
Figure 46. Glochidium of Cyprogenia stegaria (a-d) and Cyprogenia aberti (e-i). Figure 47. Glochidium of Dromus dromas; a. exterior valve, OSUM:20407.1, bar length = 30um; b. interior valve, OSUM :20407. 1, bar length = 30um; c. interior valve pitting, OSUM:23200. 9, bar length = 5um; d. interior valve pitting, OSUM:20407. 1 , bar length = lum; e. micropoints, OSUM: 23200 . 9, bar length = 2um. Figure 48. Glochidium of Actinonaias pectorosa; a. exterior valve, OSUM:48748.3, bar length = 35um; b. interior valve, O S U M :48748 . 3 , bar length = 40um; c. lateral view, OSUM: 24337 , bar length = 60um,- d. micropoints, OSUM: 24337 , bar length = Sum; e. micropoints, OSUM:24337, bar length - 2um; f. hinge, OSUM:48748.3, bar length = 20um; g. exterior valve sculpture, OSUM:48748.3, bar length = lum. Figure 49. Glochidium of Obovaria retusa UMMZ:Uncataloged (a-d) and Obovaria olivaria OSUM:51282.2 (e-h); a. exterior valve, bar length = 40um; b. interior valve, bar length = 40um; c. exterior valve sculpture, bar length = lum; d. hinge, bar length = 20um; e. exterior valve, bar length = 40um; f. interior valve, bar length = 40um; g. exterior valve sculpture, bar length - lum? h. hinge, bar length = 15um.
218 Figure 49. Glochidium of Obovaria retusa (a-d) and Obovaria olivaria (e-h). Figure 50. Glochidium of Obovaria subroturda; a. exterior valve, MAH:805.1, bar length - 30um; b, interior valve, MAH:805.1, bar length = 3 5um; c. micropoints, MAH:805.1, bar length = 3um; d. hinge, MAH:659.2, bar length = 15um? e. exterior valve sculpture, MAH:805.1, bar length = lum. Figure 51. Glochidium of Obovaria iacksoniana (a-d,g) OSUM:50233.8 and Obovaria unicolor (e,f,h); a. exterior valve, bar length = 30um; b. interior valve, bar length - 30um; c. exterior valve sculpture, bar length = lum; d. hinge, bar length = 15um; e.exterior valve, OSUM:33158, bar length = 30um; f. interior valve, OSUM:3 3158, bar length = 30um; g. micropoints, OSUM: 33158, bar length = 2um; h. micropoints, OSUM:47696.6, bar length = Bum.
221 222
ili -*Vfift 9
Figure 51. Glochidium of Obovaria j acksoniana Figure 52. Glochidium of Ellipsaria lineolata, OSUM:1984:14; a. exterior valve, bar length = 45um; b. interior valve, bar length = 45um; c. lateral view, bar length = 35,um; d. micropoints, bar length = 5um; e. hinge, bar length = 15um; f. exterior valve sculpture, bar length = lum. Figure 53. Glochidium of Leptodea fragilis, MAH:626.1; a. exterior valve, bar length = lOum; b. interior valve, bar length = lOum; c. lateral view, bar length = lOum; d. micropoints, bar length = 2um; e. exterior valve sculpture, bar length = lum. Figure 54. Glochidium of Leptodea ochracea, MAH:896; a. exterior valve, bar length = 35um; b. interior valve, bar length = 35um; c. lateral view, bar length = 40um; d. hinge, bar length = 15um; e. micropoints, bar length = 5um. Figure 55. Glochidium of Lastena ohiensis. OSUM:54520.1; a. exterior valve, bar length = 25um; b. lateral view, bat length = 30um; c. hinge, bar length = lOum; d. exterior valve sculpture, bar length = 2um; e. micropoints, bar length = 5um. 227 Figure 56. Glochidium of Lastena amphichaena, OSUM:33163.13; a. exterior valve, bar length = 25um; b. micropoints, bar length = Sum; c. hinge, bar length = lOum; d. exterior valve sculpture, bar length = 2um; e. micropoints, bar length = 2um. Figure 57. Glochidium of Fotamilus alatus; a. exterior valve, OSUM:55465, bar length = 50um; b. interior valve, OSUM:55465, bar length = 50um; c. lateral view, OSUM:55465, bar length = 50um; d. lanceolate hook, OSUM:1983 : 58 , bar length = 5um; e. exterior valve sculpture, OSUM:55465, bar length = lum; f. hinge, OSUM:55465, bar length = 15um. 229 Figure 58. Glochidium of Pot:amilus purpuratus, OSUM:15738 . 2; a. exterior valve, bar length = 50um; b. interior valve, bar length = 50um; c. lateral view, bar length = 50um; d. micropoints, bar length = Sum; e. exterior valve sculpture, bar length = lum; f. hinge, bar length = 15um. i 230 Figure 59. Glochidium of Liqumia recta, OSUM:1984:2; a. exterior valve, bar length = 30um; b. exterior valve, bar length = 35um; c. lateral view, bar length = 35um; d. micropoints, bar length = 3um,- e. micropoints, bar length = 5um. 231 Figure 60. Glochidium of Venus t.aconcha e. e Hi p s if ormis, MAH:947.2; a. exterior valve, bar length = 35um; b. exterior valve, bar length = 35um; c. micropoints, bar length = 2um; d. micropoints, bar length = 2um; e. exterior valve sculpture, bar length = lum; f. interior valve pitting and adductor muscle scar, bar length = lOum; g. hinge, bar length = 15um. 232 Figure 61. Glochidium of Villosa trabalis (a,b,d,e) OSUM:9516.49, and Villosa perpurpurea (c) OSUM:1626 2; a. exterior valve, bar length = 35um; b. interior valve, bar length = 3 5um; c. exterior valve, bar length = 40um; d. micropoints, bar length = 2um; e. exterior valve sculpture, bar length = lum. Figure 62. Glochidium of Villosa villosa; a. exterior valve, OSUM:45940 7, bar length = 40um; b. interior valve, OSUM:45940 3, bar length = 40um; c . exterior valve, OSUM:45940 7, bar length = 40um; d. interior valve, OSUM:45940 7, bar length 40 um t• e. micropoints, OSUM:45940 3, bar length = Sum; f. micropoints, OSUM:45940 3, bar length = 2um; g exterior valve sculpture, OSUM:45940 7, bar length = lum. 233 234 235 Figure 63. Glochidium of Villosa vibex; a. exterior valve, OSUM:24124, bar length = 40um;b. interior valve, OSUM:24124, bar length = 40um; c. adductor muscle insertion, OSUM: 54631, bar length = 5um,- d. micropoints, OSUM: 54631 , bar length = 5um; e. exterior valve sculpture, OSUM:54631, bar length = 2um; f. exterior valve sculpture, OSUM:24124, bar length = 2um. Figure 64. Glochidium of Villosa i.. iris; a. exterior valve, OSUM:55828.4, bar length = 50um; b. interior valve, MAH:641.1, bar length = 40um; c. exterior valve, MAH:641.1, bar length = 40um; d. umbo, MAH:641.1, bar length - 15um; e. exterior valve sculpture, MAH:641.1, bar length = lum; f. micropoints, MAH:641.1, bar length = Bum. 236 237 Figure 64. Glochidium of villosa i. iris. 2 38 Figure 65. Glochidium of Lampsilis t. teres; a. exterior valve, OSUM: 51669.2, bar length = 35um; b. interior valve, OSUM: 51669.2, bar length = 40um; c. hinge, OSUM: 36409 , bar length = 15um; d. exterior surface sculpture, OSUM:51669,2 , bar length = lum; e. micropoints, OSUM:51669.2, bar length = Sum. Figure 66. Glochidium of Lampsilis t. anodontoides; a. exterior valve, OSUM:35612, bar length = 40um; b. interior valve, OSUM:35612, bar length = 35um; c. hinge, OSUM:41762 . 2, bar length = 15um; d. exterior valve sculpture, OSUM: 41762. 2, bar length = lum,- e. micropoints, OSUM:41762.2, bar length = 5um. 240 Figure 67. Glochidium of Lampsilis r. radiata, MAH:897.1; a. exterior valve, bar length = 45um; b. interior valve, bar length = 45um; c. hinge, bar length = 20um; d. exterior valve sculpture, bar length = lum; e. micropoints, iar length = lOum. Figure 68. Glochidium of Lampsilis abrupta; a. exterior valve, OSUM:13303, bar length = 40um; b. interior valve, OSUM:38841, bar length = 40um; c. micropoints, OSUM:13303, bar length = 2um; d. micropoints, OSUM:38841, bar length = 2 urn; e. exterior valve sculpture, OSUM: 1 3303 , bar length = lum; f. hinge, OSUM:13303, bar length = 15um. 242 Figure 69. Glochidium of Lampsilis higqinsi, OSUM:49024.1; a. exterior valve, bar length = 35um; b. interior valve, bar length = 35um; c. lateral valve view, bar length = 35um; micropoints, bar length = 2um; e. exterior valve sculptur a o bar length = lum; f. hinge, bar length = 15um. Figure 70. Glochidium of Lampsilis ovata, OSUM:43164.1; a. exterior valve, bar length = 40um; b, interior valve, bar length = 40um; c. micropoints, bar length = bum; d. exterior valve sculpture, bar length = lum; e. hinge, bar length = 20um; f. hinge, bar length = 20um. Figure 71. Glochidium of Lampsi1is ventricosa; a. exterior valve, MAH:954.6, bar length = 40um; b. interior valve, MAH:954.3, bar length = 40um; c. lateral view, OSUM:44619, bar length = 40um; d. micropoints, MAH:954.3, bar length = 2um; e. micropoints, MAH:954.4, bar length = 2um; f. exterior valve sculpture, MAH:954.1, bar length = lum; g. hinge, MAH:954.6, bar length = 15um. Figure 72. Glochidium of Lampsilis breviculata; a. exterior valve, OSUM:45363.35, bar length = 40um; b. interior valve, OSUM:45363.20, bar length = 40um; c. hinge, OSUM:45363.50, bar length = 15um; d. exterior valve sculpture, OSUM:45363.50, bar length = lum; c. micropoints, OSUM:45363.35, bar length = Bum. Figure 73. Glochidium of Lampsills crocata j a. exterior valve, OSUM:42060.1 bar length = 40um; b. interior valve OSUM:42060.1 bar length = 50um; c. lateral view, OSUM:54485.1 bar length - 50um,- d. micropoints, OSUM:54485.1 bar length = 2um; e. exterior valve sculpture, OSUM:54485.1 bar length = lum; f. micropoints, OSUM: 42060. 1 bar length = 5um. 247 Figure 74, Glochidium of Lampsilis cariosa, OSUM:54500; a. exterior valve, bar length = 45um; b. interior valve pitting and adductor muscle scar, bar length = 15uirt; c. exterior valve sculpture, bar length = lum; d. micropoints, bar length = 5um. Figure 75. Glochidium of Lampsilis fasciola; a. exterior valve, OSUM:55033.2, bar length = 45um; b. interior valve, OSUM:55033.2, bar length = 45um; c. lateral view, OSUM:25467, bar length = 40um; d. micropoints, OSUM:55033.2, bar length = Sum; e. exterior valve sculpture, OSUM:55033.2, bar length = lum; f. hinge, OSUM:55033.2, bar length = 15um. 249 Figure 76. Glochidium of Epioblasma triguetra, MAH:688.1; a. exterior valve, bar length = 35um; b. interior valve, bar length = 40um,- c. interior valve, bar length = 40um; d. supernumerary hook and micropoints, bar length = 2um; e. micropoints, bar length = 5um: Figure 77. Glochidium of Epioblasma brevidens, OSUM:16173; a. exterior valve, bar length = 40um; b. interior valve, bar length = 40um; c. supernumerary hook and micropoints, bar length = Bum; d. adductor muscle scar, bar length = 20um; c. exterior valve sculpture, bar length = lum; f. hinge, bar length = 25um. 251 Figure 78. Glochidium of Epioblasma capsaeformis, OSUM: 42007; a. exterior valve, bar length = 35um,- b. interior valve, bar length = 35um; c. micropoints, bar length = 5um; d. supernumerary hook, bar length = 5um; c. interior valve, bar length = 35um; f. exterior valve sculpture, bar length = lum; g. hinge, bar length - 25um. Figure 79. Glochidium of Epioblasma torulosa ranqiana; a. exterior valve, MAH:632.1, bar length = 40um; b. interior valve, MAH:632.1, bar length = 35um; c. interior valve, MAH:632.1, bar length = 35um; d. hinge, MAH:701, bar length = 25um; e. micropoints and supernumerary hooks, MAH:701, bar length = 5um; f. exterior valve sculpture, MAH:632.1, bar length - lum. CHAPTER IV UNIONID SYSTEMATICS AND THE GLOCHIDIUM Attraction. Attachment and Encapsulation The proceeding chapter demonstrated that glochidial structures change throughout linages. Take as examples the extent of lateral valve gape in the Leptodea - Fotamilus line, increasing valve depression in the Obliquaria - Dromus line, dorsal alae development in the Ptychobranchus Lampsilis line, and microstylet number and organization in the Anodonta - Lasmiqona line. Because a glochidium does not engage in any significant activities (ie. flee danger, search for food) other than those necessary to parasitize a host, it is suggested that there will be no other competing constraints on morphology. Therefore, one may ask, how does the structure of a glochidium enhance its ability to attract a host, facilitate attachment to the host, and induce encapsulation once attachment has been gained? Host attraction is generally considered to be a function of the female unionid mollusk (see Morrison, 1973 for many examples of host attraction devices used by female Unionidae). However, glochidial and pre-glochidial developmental stages contribute, at least passively, to host 253 254 attraction in Strophitus. Fusconaia, Fleurobema. Obliquaria, Cyproqenia and Dromus. The members of these genera release their glochidia in conglutinates that may be white to pink or crimson (depending on the percentage of white glochidia to red pre-glochidial developmental stages). These conglutinates are coiled (in cyproqenia). flat or tubular and resemble worms (Chamberlain, 1934; Morrison, 1973). The glochidia within these conglutinates are morphologically depressed (in Strophitus. Cyproqenia and Dromus) or their height is about equal to their length (the remaining genera). Morphological valve depression is not unique to these genera (see Pressodonta and Epioblasma). but these glochidia (with the exception of the members of Strophitus) have very small, ventrally placed adductor muscles. Valve depression in these glochidia may be a result of adaptation to conserve space in the worm-like conglutinates and to conserve the appearance of the "bait". Morphological valve depression in Strophitus may be partially a result of packaging the glochidia in the conglutinate, however its large adductor muscle indicates that aspects of valve adduction during attachment also play a role in its morphology. The adductor muscle of a glochidium is a flexor spanning an angle (gape) with the hinge (fulcrum) separating right and left valves (lever arms). The adductor muscle provides the force in a third class lever system in which 255 the resistance is here considered to be concentrated at the ventral margins of the valves. It should be noted that the large styliform hooks of the triangulate glochidia, the lanceolate hooks of Potamilus, the small attenuate hooks of Epioblasma. and the denticulate flange of a majority of the amblemine and lampsiline glochidia are restricted to the ventral margins. The effect of the interaction of cross-striated muscle, form and placement of the muscle has been reexamined recently (Gans et al., 1985; Gans and de Vree, 1987). Like cross-striated muscle, obliguely-striated glochidial adductor muscle (Heffelfinger, 1969; Zs.-Nagy and Labos, 1969) contains cells, or fibers, composed of linear series of contractile units. Contraction occurs when bonds between interdigitating thick and thin filaments are activated to draw the filaments past each other. Assuming sarcomeric equivalency between sarcomeres in a single adductor muscle and among species of glochidia {see Gans and de Vree, 1987 for a discussion of equivalent sarcomeres) the force generated by the muscle is proportional to its cross- sectional area. Therefore, for the muscle as a whole, force is proportional to the number of sarcomeres arranged in parallel (cross-sectional area) and speed of valve adduction is proportional to the number of sarcomeres in series (the contractions of individual sarcomeres are additive and time is constant). Assuming the resting gape of the glochidial 256 valve is constant, an adductor further from the hinge must be longer with more sarcomeres in series and should be intrinsically faster. Conversely, an adductor closer to the hinge must be shorter, and assuming the volume of the muscle is constant, will have more sarcomeres in parallel and should produce more force. The situation is complicated, however, by several other considerations. First, acceleration of the valves depends on force applied. A large adductor muscle (in cross -section) will produce more force and therefore more acceleration- Second, a given gape can be bridged by fibers with a few fully extended sarcomeres or many partially contracted sarcomeres. Extension and peak isometric tension are the same in both cases, but the latter can begin contraction closer to the plateau region (corresponding to the period when bonding between thick and thin filaments is at its peak). Third, effective force, producing rotation at the hinge rather than translation, varies with the angle of attachment and increases with adduction of the valves (as the angle of attachment approaches 90°). These considerations suggest many options for adductor muscle size and location, but in each case the larger the cross -sectional area of the muscle the more force and speed obtained. Suppose, however, that valve gape is not constant. Reducing gape produces two benefits: first, sarcomeres can 257 be retained in parallel, and second, the angle of attachment can be closer to 90°. However, reducing gape has the obvious effect of decreasing area of valve sweep. Thus, the trade-off is not between speed and grip, but between gape (area of sweep) and grip (holding on to the host). Given the above, we can identify a number of scenarios for the relationship between valve dimensions and adductor muscle size relative to mode of glochidial attachment. If selection is for forceful grip, then a large diameter muscle is necessary. Therefore, if the number of sarcomeres is limited, diameter should be favored over length, and gape will be reduced. However, forceful grip is also produced by a relatively short resistance arm. Regardless of the position of the muscle, both force and gape are improved by valve depression and therefore large diameter adductor muscles and depressed shells should occur together. If selection is for maximum area of sweep, then the adductor muscle should be relatively close to the hinge. However, a decreasing effective force and packaging problems (ie. the position of other larval tissues and room for circumferential expansion of the muscle during contraction) may limit the proximity of the muscle to the hinge. With these constraints on morphology, a large gape can be achieved only by lengthening the adductor muscle. Assuming the volume of the muscle is constant, then its diameter must decrease, and glochidia with long resistance arms (high 258 shells) should also have small adductor muscles (in cross-section). Figure 80 demonstrates that these predictions hold true for a majority of the glochidia examined. The least squares regression for the relationship between degree of valve depression and relative adductor muscle cross-sectional area is significant (r=0.800, p<0.001, n=134). Figure 80 shows that glochidia with the longest resistance arms have the smallest adductor muscles, whereas morphologically depressed glochidia have the largest adductor muscles. The conditions that effect contraction of the glochidial adductor muscle and induce permanent closure of glochidial valves have been studied (Lefevre and Curtis, 1912; Arey, 1921; Heard and Hendrix, 1965). These studies have shown that the stimulus caused by a passing fin, the action of passing through the gill chamber of a fish, the presence of small concentrations of fish blood in the near environment, or many other examples of lesser importance to successful parasitism, cause glochidia to adduct their valves. During initial contact with the host, the glochidium with the largest sweep and fastest response will have the greatest chance to gain attachment. When attachment is achieved, however, the glochidium that can hold on tightly will have a greater chance for remaining attached. It is important to note that most of the morphologically depressed glochidia with large diameter Figure 80, Adductor muscle size increases with increasing glochidial valve depression. Closed circles represent the Anodontinae, triangles represent the Ambleminae, and open circles represent the Lampsilinae. The glochidium of Fegias fabula was not plotted but was included in regression analysis {see Table 2 for the data used to construct this figure). 259 iue 0 Adco msl sz icess ih increasing with increases size muscle Adductor 80. Figure glochidial valve depression. valve glochidial % Adductor Muscle Area Relative to Valve Area 10 15 5 2 20 0 3 5 0.1 0.2 0.3 I n c r e a s i n g V a l v e D e p r e s s i o n - V a l v e L e n g t h / V a l v e H e i g h t 0.4 0.5 0.6 0.7 0.8 O * O 0.9 1.0 1.1 1.2 1.3 260 1.4 261 adductor muscles are members of the Anodontinae (the members of Epioblasma are the only exceptions). Anodontine glochidia are almost always found attached to the exterior surface of the host. Furthermore, these glochidia have been found to selectively attach to the tail and pectoral fins (actively moving fins) rather than the anal, dorsal and pelvic fins (Dartnall and Walkey, 1979; Dudgeon and Morton, 1984). This selectivity may be a result of the probability of contact (actively moving fins sweep more area and come in contact with more glochidia) but the turbulence caused by the motion of these fins would tend to dislodge a glochidium. Forceful grip would have a selective advantage in this situation. The glochidia of Potamilus are not explained by the relationship in Figure 80. These glochidia have extreme lateral valve reduction (producing the axe-head shape) and recurved lanceolate hooks. The position of Potamilus in this figure (to the left of the linear relationship) is a result of their small valve length. The effect of lateral valve reduction is a decrease in surface area and consequently a reduction in fluid drag (drag is proportional to surface area times speed squared). Therefore lateral valve reduction increases the angular momentum applied to penetration devices (lanceolate hooks) but does not affect the size of the lever arm or reduce area of sweep. 262 The cluster to the right of the linear relationship in Figure 80 and the triangle near the bottom of the graph, represent the morphologically depressed glochidia of Cyprogenia aberti (circles) and Fusconaia ebena (triangle). These glochidia are morphologically depressed and have small, ventrally positioned adductor muscles. It was suggested above that valve depression in these glochidia could be explained in terms of conserving space within a worm-like bait structure. what consequences will the combination of depressed shells and small ventrally placed adductor muscles have during attachment? Assuming the host has been attracted to the bait, it engulfs the conglutinate containing glochidia. The membrane of the conglutinate breaks down and some glochidia may eventually come in contact with a gill filament. It appears that selection in these species is for forceful grip over area of sweep. Positioning the adductor muscle ventrally in the valve increases the force arm and produces a better angle Of attachment, both of which increase effective force and may compensate for a small diameter adductor muscle. Valve depression, however, will increase gape but at the expense of area of sweep. The location and development of dorsal alae may also be explained in terms of increased efficiency of attachment. As was pointed out numerous time in the proceeding chapter, the crystalline matrix of the glochidial valve contains pits 263 except along the valve margins. Rand and wiles (1982) proposed that these pits may enhance gas exchange and nutrient uptake during encapsulation. However, the demonstration that the exterior surface is covered by a periostracum-like membrane suggests a limited effectiveness for these functions. The most obvious function of the pits is to reduce the mass of the valve in order to increase force. A consequence of this, however, is that during valve adduction the force produced at the margins of the valve (especially the ventral margin) can not be transmitted in a straight line across the disc but must travel around the margin of the valve (within the unpitted marginal band). Dorsal alae, characteristic of the Ptychobranchus Lampsilis line are located at the dorsal - lateral margins of the valves, extend about as far ventrally as the adductor muscle and become longer and more arched with increasing valve height. These observations suggest that dorsal alae, like the unpitted marginal band, act to transmit force and that dorsal alae development correlates with the general pattern of stress lines and tension lines produced during adduction (Hildebrand, 1974, see especially Figure 18-2H). Hooks, microstylets and micropoints serve a much different function during attachment. These devices not only secure a hold on host tissue but they rip the flesh of the host, releasing blood which provides the stimulus necessary for continuous contraction of the adductor muscle 264 until encapsulation occurs (Heard and Hendrix, 1965). Therefore, selection acting on hooks, microstylets and micropoints should develop piercing structures that increase surface area for attachment. Surface area increases with an increase in the number of projections and with the organization of these projections into rows. Piercing the tissues of the host requires sharply pointed projections. We see therefore, that hook, microstylet and micropoint selection during attachment and induction of encapsulation are complementary. That is to say the conditions that increase the effectiveness of these projections during attachment (many sharply pointed projections) are the same required to effectively induce encapsulation. The phylogeny of the Unionidae, based on glochidial character states, can therefore be interpreted in regard to the use of structures to attract hosts, attach to hosts and induce encapsulation. It is clear that attachment is of fundamental importance to the development of the glochidium but that other functional considerations (attraction and encapsulation) can play a role in shaping the morphology of the glochidium when their effect is complimentary with that of attachment. 265 Higher Level Systematics Relationships of freshwater mussels at the familial and subfamilial levels have been studied using two approaches. One approach has been to look at a single suite of characters, such as shell characters (Modell, 1942) or soft parts (Heard and Guckert, 1970), and to determine the phylogenetic arrangement of species based solely on the information available in these characters. This approach has resulted in an exaggerated and cumbersome higher level classification (Modell proposed three families and 10 subfamilies of Nearctic freshwater mussels and Heard and Guckert concluded that the Nearctic fauna comprises two families and nine subfamilies) possibly as a result of unevaluated convergence in character states (Davis and Fuller, 1981). The second approach has been to look at all available data in an attempt to evaluate the heuristic value of those characters. Here again there have been two approaches; 1) to assess the value of one data set based on its agreement with another data set, and 2 ) to interpret the characters based on their evolution. Examples of the first approach include the electrophoretic and immunological studies of Davis and Fuller (1981), Davis et al. (1981) and Davis (1984) and the karyological studies of Jenkinson (1983). Ortmann (1910a, 1912) provides examples of the second approach. 266 The present study attempts to redefine the role of the glochidium in unionid systematics by an interpretation of the evolution of glochidial characters. It was suggested above that many, if not all, glochidial characters can be interpreted on the basis of their function during host attraction, attachment, and induction of encapsulation. It is also observed that glochidial adductor muscle size (an obvious glochidial structure) and the degree of valve depression are characters that have converged in separate linages and therefore are not useful in an evaluation of relationships. The role of the glochidium in unionid systematics has been limited in the past to separating the Unionidae into three groups; 1 ) the hooked triangulate glochidia, 2 ) the hookless elliptical glochidia, and 3) the hooked ligulate glochidia. Figure 81 demonstrates this division of species, although it should be noted that neither of the principal components shows a high correlation with shape or hook structure. The first principal component explains 3 5.5% of the variance and is loaded primarily with dorsal alae development and exterior valve sculpture. The second principal component explains 26.3% of the variance and primarily represents the position of the ligament and the length of the hinge. This figure shows that the glochidia of the Anodontinae (b-n) and Unioninae (a) group together and that the glochidia of the Ambleminae (A-c) and 267 V 10 USQT | KR 8 D I FG HIBEJ | A CX 6 W M ia f p g C h i NO A -10-cdkjmn -6 ------4------2- -2---- 4- -8 10 eb -2 : -6 -i -10 PCA 2 Figure 81. Principal Components Analysis of selected glochidia. a, Ueg; b, Acy; c, Abe; d, Akel; e, Agrl; f, Aip; g, Asu; h, Aiml; i, Sami; j, Sunl; k, Phe; 1, Pfbl; m, Aun; n, Lcsl; A, Mne; B, PdO; C, Edi; D, Pf al; E, Pgr; F, Ore; G# Cst; H, Cab; I, Ddrl; Apel; K, Obr; L, Eli; M, Lfr; N, Loc; O, Loh; P, Pall; Q, Lre; R, Vtr; S, Vvll; T, Virl; U t Ltel; V, Lvel; W, Etr; X, Eral. See Table 5 (Appendix C) for the identity of taxa abbreviated here. 268 Lampsilinae (D-X) are very similar. Furthermore, this figure demonstrates that the glochidia of Potamilus (P), Lastena (0), Leptodea (M-N), and Ellipsaria (L) ally these genera and distinguish them from the remaining Lampsilinae. The relationships among the Anodontinae and Unioninae are further clarified in Figure 82. The first principal component represents 64.6% of the variance and is loaded primarily by exterior valve sculpture and micropoint structure. The second principal component explains 9.2% of the variance and is strongly correlated with size (primarily valve length). This figure shows that Unio (A), although distinguished from the Anodontinae morphologically and in shell structure, has a glochidium that is similar to that found in Simpsonaias ambigua (J). Clarke (1985) noted that the phylogenetic position of S. ambigua was uncertain. This study suggests that this species broke away form the the main Unio - Anodonta line early in the development of the Anodontinae and that its peculiar life history (with the mudpuppy, Necturus maculosus, as host) and resulting isolation have helped perpetuate the primitive character of this species, including its glochidium. The glochidia of A. implicata (G) and A. suborbiculata (H) are also not much advanced beyond that of Unio. These glochidia have the same hook structure, but they are larger than that of Unio and 269 10 FB I c I E 8 D I I | 6 N KL 4 A J H P M C A -10---- 8 6 ---- 4---- 2- - 8- -10 1 -2 -4 -6 -8 -10 PCA 2 Figure 82. Principal Components Analysis of selected anodontine glochidia. A, Ueg; B, Acy; C, Aanl; D, Abe; E, Akel; F, Agrl; G, Aip; H, Asu; I, Aiml; J, Sami; K, Sunl; L, Phe; M, Pfbl; N, Aun; O, Lcsl. See Table 5 (Appendix C) for the identity of taxa abbreviated here. 270 are further distinguished by valve shape or exterior valve sculpture. The remaining species separate into the tribes Anodontini (Anodonta and Anodontoides; B-F,I) and Alasmidontini (Strophitus, Fressodonta. Peqias, Alasmidonta. Arcidens and Lasroiqona; K-O) (see Clarke, 1981a, 1985). It should be noted that the genus Strophitus (K, S. u. undulatus) is grouped with the Alasmidontini here. The relationships among the members of the Lampsilinae are clarified in Figure 83. The first principal component explains 62.8% of the variance and is correlated with central ligament position and dorsal alae development. The second principal component represents 11.9% of the variance and is related to glochidial size, primarily valve height and hinge length. The three clusters of points represent three lineages within the Lampsilinae. The separation of Potamilus, Lastena, Leptodea and Ellipsaria from the remaining members of this subfamily has already been demonstrated (Figure 81) and has not been repeated here. The cluster near the center of the plot (A-G) represents the lampsiline genera with glochidia that show the most similarity with the glochidia of the Ambleminae. From this group of species the higher lampsiline genera (H-N) are believed to have developed (Ortmann, 1912). Ortmann's conclusion that Ptvchobranchus represents the most primitive type within this lineage is supported by glochidial characters. Furthermore, Ortmann (1912) has suggested 2 7 1 10 KMN I 8 LH G B EF D P C A - 10 - ■ 8- -8 10 -2 -6 -l -10 PCA 2 Figure 83. Principal Components Analysis of selected lampsiline glochidia. A, Pfal; B, Pgr; C, Ore; D, Cst; E, Cab; F, Ddrl; G, Apel; H, Obr; I, Lre; J, Vtr; K, Vvll; L, Virl; M, Ltel; N, Lvel; O, Etr; P, Eral; Q, Aiml. See Table 5 (Appendix C) for the identity of taxa abbreviated here. 272 that Epioblasma (0-P) is a derived member of this subfamily since the females develop mantle extensions (discussed above) that are unique to this genus. It is less clear, however, at what level of development this genus broke away from the Ptychobranchus - Lampsilis line. Here again, glochidial characters support Ortmann1s conclusion (the glochidia of Epioblasma possess unique characters such as supernumerary hooks and vertically rather than horizontally aligned micropoints) but it is still unclear how this genus is related to the remaining Lampsilinae. The analysis, as presented above, supports a higher classification of the Unionidae that resembles those developed through a synthesis of available data on morphology, distribution and cellular characteristics. In general the arrangement of subfamilies based upon glochidia is similar to that proposed by Ortmann (1912). Ortmann divided the North American Unionidae into three subfamilies; Anodontinae, Ambleminae (ortmann's Unioninae) and Lampsi*linae. An additional European subfamily (Unioninae) also belongs to this family and represents the sister group of the Anodontinae as suggested by Morrison (1955). The Ambleminae and the Lampsilinae may also be sister groups, however, Davis and Fuller (1981) have proposed that these two subfamilies are monophyletic and therefore not deserving of separate subfamily status. It should be noted that the amblemine and primitive lampsiline glochidia clustered 273 together in Figure 81 in support of the conclusion of Davis and Fuller (1981). However, too few amblemine glochidia were examined to adequately settle this debate, and for this reason the amblemine glochidia were treated separately from the lampsiline glochidia in this report. Furthermore, the Lampsilinae can be distinguished anatomically from the Ambleminae and two glochidial characters (dorsal alae and position of the central ligament) separate the main line of the Lampsilinae from the Ambleminae. There is little doubt that these subfamilies are sister groups, based on their very similar glochidia, however the level of relationship, whether at the subfamily or tribe level, is still open for d e b a t e . SUMMARY One of the primary objectives of this study was to assess the value of glochidial characters in unionid systematics. Although it can not be said that an examination of glochidia alone will distinguish all species of Unionidae (see the very similar glochidia of the genus Lampsilis > , it is true that in many cases the glochidium of a species has a unique combination of characters that helps distinguish it from all others. Furthermore, the evolution of these characters identify trends in the evolution of the Unionidae. In many cases these trends are also reflected in adult characters. Listed below are the results of this study: 1. A method was developed to remove the preserved soft parts from glochidia. This technique produces clean glochidia from specimens stored in alcohol or buffered formalin (in the marsupia of preserved females). 2. Glochidial orientaion was determined by examining the glochidial valves present at the umbones of juvenile shells. The orientation of the glochidial valve was assigned to 274 275 correspond to the orientation of the juvenile valve. 3. The glochidiurn of Unio elonqatulus qlaucinus was found to share .many characters with the Anodontinae (especially Simpsonaias ambiqua) and the subfamily Unioninae is suggested as the sister group to the Anodontinae. This was previously proposed by Ortmann (1912) and Morrison (1955). 4. The Alasmidontini (recently revised by Clarke, 1981a, 1985) is rearranged to reflect glochidial structure. Adult characters were also found to support this new arrangement. Strophitus, Pressodonta and Peqias have a glochidiurn that is depressed pyriform, with a large adductor muscle (in cross- section), looped exterior valve sculpture, and a double row of microstylets on the hook. The glochidiurn of Alasmidonta. Arcidens and Lasmiqona is high pyriform, with a small adductor muscle, beaded to rosette exterior valve sculpture, and a complex hook with at least four rows of microstylets. Eliminating relative valve depression and adductor muscle size (due to convergence in these characters as a result of similarity in modes of attachment) still leaves two well characterized groups. 5. A new arrangement of the species of Alasmidonta and Lasmiqona is proposed that reflects the rearrangement of the Alasmidontini presented above. The genus Alasmidonta 276 includes the following examined species; A. undulata, A. marginata. The genus Lasmiqona includes the following examined species; L. costata, L. complanata. The genus Pressodonta was established to include species formerly placed in Alasmidonta and Lasmiqona. This genus contains the following examined species; P. viridis. P. heterodon. p. compressa, P. subviridis. P. holstonia. 6 . The Lampsilinae are divided into four lineages based on glochidial characters. The phylogenetic arrangement of these lineages is supported by the anatomical studies of Ortmann (1910a, 1911, 1912, 1919). The main lineage within the Lampsilinae is from Ptychobranchus to Actinonaias, Obovaria, Liqumia, Venustaconcha. Villosa and Lampsilis. Off-shoots from this main lineage include; 1 ) Obliquaria, Cyprogenia, Dromus; 2) Ellipsaria. Leptodea. Lastena, Potamilus; 3) Epioblasma. 7. The glochidiurn of Leptodea ochracea allies this species with Leptodea fraqilis rather than Lampsilis cariosa. This is in aggreement with Morrison (1975). 8 . The glochidia of Lastena ohiensis and Lastena amphichaena ally these speies with Leptodea fraqilis rather than Potamilus alatus. Potamilus, formerly containing all axe-head glochidia, is divided into Potamilus s. s. (P. 277 alatus, P. purpuratus and P. capax) and Lastena {L. ohiensis, L. amphichaena, and L. inf lata) . It is proposed that the axe-head shape of the glochidia of these species is a result of convergence. A mechanism for this convergence is proposed. 9. An analysis of glochidial structure supports the higher classification of the Unionidae proposed by Ortmann (1912). Aspects of the higher level classification proposed here for the Unionidae resembles those suggested by Davis and Fuller (1981), Morrison (1955) and Jenkinson (1983). APPENDIX A Proposed Glochidia-Host Relationships 278 Table 3. Proposed glochidia-host relationships for North American Unionidae Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Margaritiferidae Margaritifera margaritifera Salmo trutta Clarke and Berg, 1959:18 X Salvelinus fontinalis Clarke and Berg, 1959:18 X falcata Oncorhynchus tshawytscha Davis, 1946:35 Fustish et al., 1978:155 X Karna et al., 1978:531 X Oncorhvnchus kisutch K a m a et al., 1978:531 X Salmo qairdneri Davis, 1937:35 X X Murphy, 1942:94 X X Karna et al., 1978:531 X Salmo trutta Murphy, 1942:94 X X Salmo clarki Karna et al., 1978:531 X Salvelmus fontinalis Murphy, 1942:94 X Richardsoninus egregius Murphy, 1942:94 X Catostomus tahoensis Murphy, 1942:94 X hembeli Notropis chrysocephalus Hill, 1987:10 X Notropis umbratilis Hill, 1987:10 X Notemiqonus crysoleucas Hill, 1987:10 X Unionidae Anodonta beringiana Oncorhvnchus nerka Cope, 1959:159 X Oncorhvnchus tshawytscha Cope, 1959:159 X Gasterosteus aculeatus Cope, 1959:159 X (VJ 'J VO Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS grandis Lepisosteus osseus Trdan and Hoeh, 1982:383 X Alosa chrvsochloris Surber, 1913:106 X Wilson, 1916:340 X Dorosoma cepedianum Wilson, 1916:339 X Cyprinus carpio Lefevre and Curtis, 1910:103 X Morrison In Clarke and Berg, 1959:39 X Notemiqonus crvsoleucas Lefevre and Curtis, 1910:103 X Read and Oliver, 1953:76 X Trdan and Hoeh, 1982:383 X Rhinichthvs atratulus Trdan and Hoeh, 1982:383 X Semotilus atromaculatus Trdan and Hoeh, 1982:383 X Semotilus marqarita Trdan and Hoeh, 1982:383 X Notropis umbratilis Trdan and Hoeh, 1982:383 X Notropis cornutus Trdan and Hoeh, 1982:383 X X Notropis heterodon Trdan and Hoeh, 1982:383 X X Notropis heterolepis Trdan and Hoeh, 1982:383 X X Campostoma anomaliun Trdan and Hoeh, 1982:383 X X Ictalurus natalis Wilson, 1916:338 X Fundulus diaphanus Trdan and Hoeh, 1982:383 X Labidesthes sicculus Trdan and Hoeh, 1982:383 X X Pimephales notatus Trdan and Hoeh, 1982:383 X X Culaea inconstans Morrison In Clarke and Berg, 1959:38 X Trdan and Hoeh, 1982:383 X Morone chrvsops Wilson, 1916:340 X Pomoxis annularis Lefevre and Curtis, 1910:103 X Wilson, 1916:340 X Morrison In Clarke and Berg, 1959:38 X Pomoxis niqromaculatus Wilson, 1916:340 X 280 Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Trdan and Hoeh, 1982:383 X X Ambloplites rupestris Lefevre and Curtis, 1910:103 X Tucker, 1928:126 X Trdan and Hoeh, 1982:383 X X Micropterus salmoides Wilson, 1916:339 X Penn, 1939:101 X Morrison In Clarke and Berg, 1959:39 X Trdan and Hoeh, 1982:383 X Lepomis cvanellus Wilson, 1916:338 X Tucker, 1928:126 X Trdan and Hoeh, 1982:383 X Lepomis macrochirus Lefevre and Curtis, 1910:103 X Wilson, 1916:339 X Penn, 1939:101 X Morrison In Clarke and Berg, 1959:38 X Trdan and Hoeh, 1982:383 X X Lepomis megalotis Penn, 1939:101 X Lepomis gibbosus Trdan and Hoeh, 1982:383 X Perea flavescens Lefevre and Curtis, 1910:103 X Trdan and Hoeh, 1982:383 X X Etheostoma nigrum Hankinson, 1908:235 X Morrison In Clarke and Berg, 1959:39 X Trdan and Hoeh, 1982:383 X X Etheostoma exile Morrison In Clarke and Berg, 1959:39 X Trdan and Hoeh, 1982:383 X X Etheostama caeruleum Trdan and Hoeh, 1982:383 X X Aplodinotus grunniens Wilson, 1916:338 X 281 Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date*.page NI NT LI LT BI NS cataracta Cyprinus carpio Lefevre and Curtis, 1910:104 X Lepomis qibbosus Conner, 1905:142 X implicata Alosa pseudoharengus Johnson, 1946:112 X Davenport et al., 1965:R76 X Catostomus commersoni Davenport et al., 1965:R76 X Morone americana Davenport et al., 1965:R76 X Lepomis qibbosus Davenport et al., 1965:R76 X imbecillis Semotilus atromaculatus Morrison In Clarke and Berg, 1959:42 X Fundulus diaphanus Trdan and Hoeh, 1982:383 X Gambusia affinis Stern and Felder, 1978:233 X Ambloplites rupestris Trdan and Hoeh, 1982:383 X Micropterus salmoides Trdan and Hoeh, 1982:383 X Lepomis qulosus Stern and Felder, 1978:233 X Lepomis cyanellus Tucker, 1927:288 X Trdan and Hoeh, 1982:383 X Lepomis macrochirus Stern and Felder, 1978:233 X Trdan and Hoeh, 1982:383 X Lepomis qibbosus Trdan and Hoeh, 1982:383 x Lepomis marqinatus Stern and Felder, 1978:233 X Perea flavescens Trdan and Hoeh, 1982:383 X californiansis Gambusia affinis D'Eliscu, 1972:57 X Anodontoides ferussacianus Fetromyzon marinus Wilson and Ronald, 1967:1085 X Cottus bairdi Morrison In Clarke and Berg, 1959:36 X 282 Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Simpsonaias ambigua Necturus maculosus Howard, 1915:7 X X Howard, 1951:2 X X Strophitus undulatus Semotilus atromaculatus Howard In Baker, 1928:201 X Fundulus zebrinus Ellis and Keim, 1918:18 X Micropterus salmoides Howard In Baker, 1928:201 X Lepomis cvanellus Ellis and Keim, 1918:18 X Pressodonta viridis Etheostoma nigrum Morrison In Clarke and Berg, 1959:30 Cottus bairdi Morrison In Clarke and Berg, 1959:30 X X Cottus carolinae Zale and Neves, 1982b:386 X compressa Lebistes reticulatus Tompa, 1979:189 Alasmidonta marginata Moxostoma macrolepidoturn Howard and Anson, 1922:80 X Hypentelium nigricans Howard and Anson, 1922:80 X Catostomus commersoni Howard and Anson, 1922:80 X Ambloplites rupestris Howard and Anson, 1922:80 X Lepomis gulosus Howard and Anson, 1922:80 X Arcidens confragosus Anguilla rostrata Wilson, 1916:338 X Dorosoma cepedianum Surber, 1913:105 X Wilson, 1916:339 X Pomoxis annularis Surber, 1913:105 X Wilson, 1916:340 X Ambloplites rupestris Surber, 1913:105 X Wilson, 1916:338 X Aplodinotus qrunniens Wilson, 1916:338 X £ u> Table 3, Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Lasmiqona costata Cyprinus carpio Lefevre and Curtis, 1910:111 X complanata Cvprinus carpio Lefevre and Curtis, 1910:111 X Pomoxis annularis Lefevre and Curtis, 1912:168 X Micropterus salmoides Lefevre and Curtis, 1910:110 X Lepomis cyanellus Lefevre and Curtis, 1912:168 X Maqnonaias nervosa Amia calva Howard, 1914c:31 X Anguilla rostrata Surber, 1915:8 X Wilson, 1916:338 X Coker et al., 1921:52 X Alosa chrysochloris Wilson, 1916:340 X Coker et al., 1921:153 X Dorosoma cepedianum Howard, 1914c:31 X Coker et al., 1921:152 X Carpiodes velifer Howard, 1914c:32 X Ictalurus punctatus Howard, 1914c:32 X Coker et al., 1921:152 X Ictalurus nebulosus Coker et al., 1921:152 X Ictalurus melas Howard, 1914c:32 X Coker et al., 1921:152 X Noturus qyrinus Coker et al., 1921:153 X Pylodictis olivaris Howard, 1914c:31 X Coker et al., 1921:153 X X Morone chrysops Howard, 1914c:31, 32 X X Wilson, 1916:340 X Coker et al., 1921:153 X Pomoxis annularis Coker et al., 1921:153 X X 284 Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Pomoxis nigromaculatus Howard, 1914c:?2 X Coker et al., 1921:153 X Micropterus salmoides Howard, 1914c:32 X Lepomis macrochirus Howard, 1914c:32 X Coker et al., 1921:153 X X Lepomis cyanellus Coker et al., 1921:152 X Stizostedion canadense Howard, 1914c:32 X Aplodinotus grunniens Surber, 1913:105 X Howard, 1914c:32 X Surber, 1915:8 X Wilson, 1916:338 X Coker et al., 1921:152 X X Ouadrula guadrula Pylodictus olivaris Howard and Anson, 1922:74 X cvlindrica Notropis qalacturus Yeager and Neves, 1986:335 X Notropis spilopterus Yeager and Neves, 1986:335 X Hybopsis amblops Yeager and Neves, 1986:335 X metanevra Lepomis cyanellus Surber, 1913:115 X Wilson, 1916:338 X Lepomis macrochirus Surber, 1913:115 X Howard, 1914c:17 X Wilson, 1916:339 X Coker et al., 1921:152 X Stizostedion canadense Howard, 1914c:17 X Coker et al., 1921:153 X Pearse, 1924:181 X 285 Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS intermdeia Hvbopsis dissimilis Saylor In Hill, 1986:36 Hybopsis insignis Saylor In Hill, 1986:36 nodulata Ictalurus punctatus Coker et al., 1921:152 X Pylodictus olivaris Coker et al., 1921:153 X Pomoxis annularis Surber, 1913:115 X Wilson, 1916:340 X Coker et al., 1921:153 X Pomoxis nigromaculatus Howard, 1914c:15 X Micropterus salmoides Howard, 1914c:15 X Lepomis macrochirus Howard, 1914c:15 X pustulosa Scaphirhynchus platorynchus Coker et al., 1921:153 X Ictalurus punctatus Howard, 1912:68 X Howard, 1914c;11 Wilson, 1916:339 X Coker et al., 1921:152 X Ictalurus nebulosa Howard, 1914c:11 Coker et al., 1921:152 Ictalurus melas Howard, 1912:68 X Howard, 1914c:11 Coker et al., 1921:152 X Pylodictis olivaris Howard, 1914c:11 Wilson, 1916:339 X Amblema plicata Lepisosteus platostomus Coker et al., 1921:152 X Howard and Anson, 1922:77 X Esox lucius Wilson, 1916:339 X w Coker et al., 1921:152 X oo Morone chrysops Wilson, 1916:340 X ** Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Coker et al., 1921:153 X Pomoxis annularis Surber, 1913:115 X Howard, 1914c:26, 27 X X Wilson, 1916:340 X Coker et al., 1921:153 X Pomoxis nigromaculatus Howard, 1914c:26, 27 X X Coker et al., 1921:153 X Ambloplites rupestris Stein, 1968:46 X Micropterus salmoides Lefevre and Curtis, 1912:168 X Howard, 1914c:27 X Coker et al., 1921:153 X X Lepomis gulosus Coker et al., 1921:152 X Pearse, 1924:181 X Lepomis macrochrius Howard, 1914c:27 X Stein, 1968:46 X Lepomis cyanellus Stein, 1968:46 X Lepomis qibbosus Wilson, 1916:339 X Coker et al., 1921:152 X Stein, 1968:46 X Stizostedion canadense Surber, 1913:115 X Howard, 1914c:34 X Wilson, 1916:340 X Coker et al., 1921:153 X Perea flavescens Howard, 1914c:27 X Coker et al., 1921:153 X Stein, 1968:46 X Fusconaia ebena Alosa chrvsochloris Surber, 1913:115 X to Howard, 1914c:18 X 00 ■o Wilson, 1916:340 X Table 3. Continued Unionids Vertebrate* host Reference Type of evidence Author, date:page NI NT LI LT BI NS Howard, 1917:96 X Coker, 1919:22 X Coker et al., 1921:153 X X Pomoxis annularis Howard, 1914c:18 X Pomoxis nigromaculatus Howard, 1914c:18 X Micropterus salmoides Howard, 1914c:18 X flava Pomoxis annularis Wilson, 1916:340 X Coker et al., 1921:153 X Pomoxis nigromaculatus Surber, 1913:115 X Wilson, 1916:340 X Coker et al., 1921:153 X Lepomis macrochirus Howard, 1914c:25 X Plethobasus cyphus Stizostedion canadense Surber, 1913:115 X Wilson, 1916:340 X Pleurobema oviforme Notropis galacturus Neves, 1983:158 X Notropis cornutus Neves, 1983:158 288 x x x Nocomis micropogon Neves, 1983:158 Campostoma anomalum Neves, 1983:158 cordatum Notropis ardens Yokley, 1972:361 X Lepomis macrochirus Surber, 1913:115 X Coker et al., 1921:153 X Elliptio crassidens Alosa chrvsochloris Howard, 1914c:40 X dilatata Dorosoma cepedianum Wilson, 1916:339 X Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Pylodictis olivaris Howard, 1914c:27 X Pomoxis annularis Howard, 1914c:27 X Wilson, 1916:340 X Pomoxis nigromaculatus Howard, 1914c:27 X Stizostedion canadense Howard, 1914c:27 X complanata Fundulus diaphanus Wiles, 1975:39 X Perea flavescens Lefevre and Curtis, 1912:168 X Matteson, 1948:708 X Uniomerus tetralasmus Notemigonus crysoleucas Stern and Felder, 1978:233 X Cyprogenia stegaria Carassius auratus Chamberlain, 1934:60 X Glebula rotundata Lepomis cyanellus Parker et al., 1984:56 X Lepomis macrochirus Parker et al., 1984:56 X Actinonaias liqamentina Anguilla rostrata Coker et al., 1921:152 X Noturus gyrinus Coker et al., 1921:152 X Morone chrvsops Surber, 1913:115 X Wilson, 1916:340 X Coker et al., 1921:153 X X Pomoxis annularis Lefevre and Curtis, 1912:168 X Wilson, 1916:340 X Coker et al., 1921:153 X X Pomoxis nigromaculatus Howard, 1914c:36 X Coker et al., 1921:153 X Ambloplotes rupestris Lefevre and Curtis, 1910:108 X 289 Micropterus dolomieui Coker et al,, 1921:153 X Howard and Anson, 1922:69 X Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Micropterus salmoides Lefevre and Curtis, 1910:109 X Lefevre and Curtis, 1912:168 X Wilson, 1916:339 X Reuling, 1919:340 X Coker et al., 1921:153 X X Howard and Anson, 1922:76 X Lepomis cyanellus Lefevre and Curtis, 1912:168 X Wilson, 1916:338 X Coker et al., 1921:152 X Lepomis macrochirus Wilson, 1916:339 X Coker et al., 1921:153 X Stizostedion canadense Coker et al., 1921:153 X Pearse, 1924:181 X Perea flavescens Lefevre and Curtis, 1910:108 X Coker et al., 1921:153 X X Obovaria olivaria Scaphirhynchus Howard, 1914a:43 X platorynchus Coker et al., 1921:153 X X Ellipsaria lineolata Lepomis cyanellus Surber, 1913:115 X Wilson, 1916:338 X Stizostedion canadense Surber, 1913:115 X Aplodinotus qrunniens Howard, 1914a:43, 44 X X Wilson, 1916:338 X Coker, 1919:30 X Coker et al., 1921:152 X Howard and Anson, 1922:78 X Leptodea 290 fraqilis Aplodinotus qrunniens Howard, 1912:67 X Wilson, 1916:338 X Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Lastena ohiensis Pomoxis annularis Surber, 1913:115 X Wilson, 1916:340 X Aplodinotus qrunniens Coker and Surber, 1911:181 X Surber, 1912:8 X Surber, 1913:115 X Wilson, 1916:338 X Howard and Anson, 1922:73 X Potamilus alatus Aplodinotus qrunniens Howard, 1912:67 X Wilson, 1916:338 X purpuratus Aplodinotus qrunniens Surber, 1913:105 X Surber, 1915:6 X Wilson, 1916:338 X Truncilla truncata Stizostedion canadense Wilson, 1916:340 X Aplodinotus qrunniens Wilson, 1916:338 X donaciformis Stizostedion canadense Surber, 1913:115 X Wilson, 1916:340 X Aplodinotus qrunniens Surber, 1912:8 X Surber, 1913:115 X Howard, 1912:67 X Howard, 1914a:44 X Wilson, 1916:338 X Howard and Anson, 1922:73 X Toxolasma 291 parvus Pomoxis annularis Mermilliod, 1974:235 X Lepomis qulosus Wilson, 1916:338 X Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date;page NI NT LI LT BI NS Lepomis cyanellus Mermilliod, 1974:235 X Lepomis macrochirus Mermilliod, 1974:235 X Lepomis humilis Mermilliod, 1974:235 X lividus Lepomis cyanellus Gooch In Hill, 1986:17 X Lepomis megalotis Gooch In Hill, 1986:17 X texasensis Lepomis qulosus Stern and Felder, 1978:233 X Lepomis macrochirus Stern and Felder, 1978:233 X Medionidus conradicus Etheostoma flabellare Zale and Neves, 1982a:2538 X X Etheostoma rufilineatum 2ale and Neves, 1982a:2538 X X Liqumia recta Anguilla rostrata Coker et al,, 1921:152 X Pomoxis annularis Lefevre and Curtis, 1912:168 X Wilson, 1916:340 X Coker et al,, 1921:153 X Morrison In Clarke and Berg, 1959:52 X Micropterus salmoides Lefevre and Curtis, 1912:168 X Lepomis macrochirus Lefevre and Curtis, 1912:164 X Wilson, 1916:339 X Coker et al., 1921:193 X Morrison In Clarke and Berg, 1959:52 X Stizostedion canadense Pearse, 1924:181 X subrostrata Micropterus salmoides Lefevre and Curtis, 1912:168 X Lepomis qulosus Stern and Felder, 1978:233 X Lepomis cyanellus * Lefevre and Curtis, 1912:168 X w Stern and Felder, 1978:233 X vo Lepomis macrochirus Lefevre and Curtis, 1912:184 X w Table 3. Continued Unionids Vertebrate* host Reference Type of evidence Author, date:page NI NT LI LT BI NS Stern and Felder, 1978:233 X Villosa nebulosa Gambusia affinis Neves et al., 1985:15 X Ambloplites rupestris Zale and Neves, 1982a:2538 X X Micropterus dolomieui Zale and Neves, 1982a:2538 X X Micropterus punctulatus Neves et al., 1985:15 X Micropterus salmoides Neves et al., 1985:15 X Micropterus notius Neves et al., 1985:15 X vanuxemi Cottus bairdi Neves et al., 1985:15 X Cottus bailevi Neves et al., 1985:15 X Cottus coqnatus Neves et al., 1985:15 X Cottus carolinae Zale and Neves, 1982a:2538 X X Lampsilis teres Scaphirhynchus Surber, 1913:115 X platorynchus Wilson, 1916:340 X Coker et al., 1921:153 X Lepisosteus spatul. Wilson, 1916:339 X Coker et al,, 1921:152 X Lepisosteus platostomus Howard, 1914a:43 X Wilson, 1916:339 X Reuling, 1919:337 X Coker et al., 1921:152 X X Howard and Anson, 1922:74 X Jones, 1950:22 X Lepisosteus osseus Wilson, 1916:339 X Reuling, 1919:337 X Coker et al., 1921:152 X X Jones, 1950:20 X 293 Pomoxis annularis Surber, 1913:115 X Wilson, 1916:340 X Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Coker et al., 1921:153 X Pomoxis nigromaculatus Surber, 1913:115 X Micropterus salmoides Wilson, 1916:339 X Coker, 1919:32 Lepomis gulosus Wilson, 1916:338 X Lepomis cyanellus Surber, 1913:115 X Coker et al., 1921:152 X Lepomis humilis Surber, 1913:115 X Coker et al., 1921:153 X r . radiata Perea flavescens Tedla and Fernando, 1969:710 X r. luteola Noturus gyrinus Coker et al., 1921:153 X Morone chrysops Corwin, 1920:81 X Coker et al., 1921:153 X Pomoxis annularis Coker et al., 1921:153 X Howard, 1922:77 X Trdan, 1981:246 X Pomoxis nigromaculatus Coker et al., 1921:153 X Howard, 1922:77 X Trdan, 1981:246 X Ambloplites rupestris Evermann and Clark, 1918:260 X Evermann and Clark, 1920:49 X Micropterus dolomieui Corwin, 1920:81 X Coker et al., 1921:153 X Micropterus salmoides Howard, 1914b:45 X Reuling, 1919:338 X Coker et al., 1921:153 X 294 Howard, 1922:66, 67 X Arey, 1923:378 X Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Trdan, 1981:246 X Lepomis qulosus Trdan, 1981:246 X Lepomis macrochirus Evermann and Clark, 1918:260 X Evermann and Clark, 1920:49 X Coker et al., 1921:153 X X Howard, 1922:77 X Trdan, 1981:246 X Stizostedion canadense Corwin, 1920:81 X Coker et al., 1921:153 X Stizostedion vitreum Corwin, 1920:81 X Corwin, 1921:307 X Coker et al., 1921:153 X X Trdan, 1981:246 X Perea flavescens Corwin, 1920:81 X Coker et al., 1921:153 X X Pearse, 1924:165 X Trdan, 1981:246 • X hiqginsi Micropterus salmoides Sylvester et al., 1984:556 X Stizostedion canadense Surber, 1913:115 X Wilson, 1916:340 X Coker et al., 1921:153 X Stizostedion vitreum Sylvester et al., 1984:556 X Aplodinotus qrunniens Wilson, 1916:338 X Coker et al., 1921:152 X ventricosa Pomoxis annularis Wilson, 1916:340 X Coker et al., 1921:153 X X 295 Micropterus dolomieui Coker et al., 1921:153 X Table 3. Continued Unionids Vertebrate host Reference Type of evidence Author, date:page NI NT LI LT BI NS Micropterus salmoides Lefevre and Curtis, 1912:182 X Reuling, 1919:339 X Coker et al., 1921:153 X Lepomis macrochirus Coker et al., 1921:153 X Stizostedion canadense Wilson, 1916:340 X Coker et al., 1921:153 X Perea flavescens Coker et al., 1921:153 X fasciola Micropterus dolomieui Zale and Neves, 1982a:2538 X X Epioblasma brevidens Etheostoma blennioides Yeager In Hill, 1986:44 X Etheostoma maculatum Yeager In Hill, 1986:44 X Etheostoma rufilineatum Yeaqer In Hill, 1986:44 X Etheostoma simoterum Yeager In Hill, 1986:44 X Percina caprodes Yeager In Hill, 1986:44 X Cottus carolinae Yeager In Hill, 1986:44 X capsaeformis Etheostoma maculatum Yeager In Hill, 1986:46 X Etheostoma rufilineatum Yeaqer In Hill, 1986:46 X Percina sciera Yeaqer In Hill, 1986:46 X Cottus carolinae Yeager In Hill, 1986:46 X triquetra Percina caprodes Yeager In Hill, 1986:47 X Cottus carolinae Yeager In Hill, 1986:47 X NI-Natural Infection without transformation, NT-Natural Transformation, LI-Laboratory Infection without transformation, LT-Laboratory Transformation, BI-By Infrence; A relationship was not observed, however there was evidence of a relatioship (e.g. a population of A;_ imbecillis occuring in a new pond that was stocked with M^ salmoides.).™ NS-Not specified; no evidence was given. m APPENDIX B Specimen Data 297 298 Table 4. Specimen data for glochidia examined. Unionidae (Fleming, 1828) Ortmann, 1911. Unioninae (Fleming, 1828) Morrison, 1955 Unio Philipsson, 1788 Unio elonoatulus glaucinus Spengler, 1793 MAH:2055* Rivanazzano (Pavia). [Italy]. ex. Coll. F. Giusti! Anodontinae (Rafinesque, 1820) Ortmann, 1911. Anodonta Lamarck, 1799 Anodonta cyqnea (Linnaeus, 17 58) OSUM:20911.1* "Maubroux (Genval) petit etang pres du lac", Belgium, [etang = pool, pond]. 24 January 1949. w. Adam! [glochidia from OSUM:20911.2# examined] Anodonta anatina (Linnaeus, 1758) OSUM:20912.1* "Ixelles, etang", Belgium. [etang = pool, pond]. 16 March 1950. W. Adam! [glochidia from OSUM:20912.2* examined] Anodonta berinqiana Middendorf, 1851 OSUM:3711.1* Outlet of Peper Lake, Kenai Peninsula, Alaska. 13 August 1957. R. Rausch 1 [glochidia from OSUM:3711.2# examined] Anodonta kennerlvi Lea, 1860 OSUM:52882.2* "Griffin Creek," [Snohomish Co.], Washington. January 1972. L. Gilbertson! [glochidia from OSUM:52882.3*# examined] Anodonta qrandis qrandis Say, 1829 OSUM:38467.10* Miami River, R.Mi. 82.4, at 1-75 bridge at Dayton, just above mouth of Mad River, Harrison Twp. , Montgomery Co., Ohio. 6 February 1976. D.H. Stansberyl OSUM:50838.14# Muskingum River, R.Mi. 23.7-24.7, 0.3 mi. S of Beverly, 4.4 mi E of Luke Chute Dam, Waterford Twp. , Washington Co., Ohio. 16-17 October 1980. W.N. Kasson and A.E. Spreitzerl MAH:668* Olentangy River below Fifth Ave. bridge near Ohio State University main campus, Columbus, Franklin Co., Ohio. 30 September 1984. K. Wright and K. Gallant! INHS:2247* Kankakee River at Kankakee, below hydroelectric plant, Kankakee Co., Illinois. 11 October 1985. J.M. Kasprowicz! Anodonta qrandis corpulenta Cooper, 1834 OSUM:38468.6# Miami River at R.Mi. 82.4, at 1-75 bridge at Dayton, just above mouth of Mad River, Harrison Twp., Montgomery Co., Ohio. 6 February 1976. R. Bay and D. Hudakl OSUM:47890* Stonelick Creek at Stonelick Reservoir, 1.1 mi. SW of Edenton, 2.8 mi. N of Newtonville, Wayne Twp., 299 Clermont Co., Ohio. 1 October 1978. D.H. Stansbery and K.G. B or ror1 OSUM:53653* Ohio River bank, R.Mi. 442.8-443.0, 0.3-0.4 mi. NW of Moscow, 2.2-2.4 mi. S of Point Pleasant, 6.9 mi. SE of New Richmond, Clermont Co., Ohio. 22 October 1984. K.E. Wright, W.N. Kasson and K. Gallant! Anodonta cataracta cataracta Say, 1817 OSUM:19136.2# Rideau River about 6 mi. above its mouth at Vincent Massey Park, Hogs Back, Carelton Co., Ontario, Canada. 7 October 1965. A.H. Clarke, L. Clarke and C.B. Stein! OSUM:52462.27* Great Herring Pond, S Shore by the Herring River, 0.8 mi. N of Bournedale, [1.6 mi. WNW of Sagamore], Barnstable Co., Massachusetts. 4 October 1984. D.H. Stansbery and K. Wright! [glochidia from OSUM:52462.35* examined] Anodonta cataracta marginata Say, 1817 OSUM:38962.6* "Black Moshannon Lake," [near or part of Black Moshannon Creek?], Snowshoe Twp., Centre Co., Pennsylvania. September 197 5. D.S. Gussmanl Anodonta doliaris Lea, 1863 OSUM:26405*# Potomac River along W shore Theodore Roosevelt Island, W. edge Washington D.C., just E of Arlington, Va., District of Columbia. 22 February 1970. K. Heffelfinger Olson! Anodonta implicata Say, 1829 OSUM:52463.7* Great Herring Pond, S shore by the Herring River, 0.8 mi. N of Bournedale, [1.6 mi. WNW of Sagamore], Barnstable Co., Massachusetts. 4 October 1982. D.H. Stansbery and K.E. Wright! Anodonta suborbiculata Say, 1831 OSUM: 13634*# Black River at U.S. Rt. 67 bridge W of Hendrickson, Butler Co., Missouri. 14 October 1964. C.B. Stein! Anodonta imbecillis Say, 1829 OSUM:27382“ "Columbus, O." [Franklin Co., Ohio]. 18--. Collector unknown (from Henry Moores collection). OSUM:9436.2* Lake Erie off East Sister Island, Ontario, Canada. 13 July 1960. D. Mount! OSUM:4432.3# Olentangy River below Fifth Ave. bridge, Columbus, Franklin Co., Ohio. 5 April 1961. C.B. Stein! OSUM:34463* Clear Fork Mohican River at Clear Fork State Park Campground B, 5 mi. NNW of Jelloway, Hanover Twp., Ashland Co., Ohio. 13 July 1973. E.W. Tittsler! MAH: 435* Hellbranch Run at Bausch Rd. (Co. Rt. 11) bridge, 0.7 mi. S of Galloway, 10.0 mi. SW of Columbus, Prairie Twp., Franklin Co., Ohio. 15 June 1983. M.A. Hoggarth! UWZY:24971.1*# Baraboo River, TUN, R6E, Sec. 1, NW 1/4 of NE 1/4, 25 meters downstream of dam at Baraboo Sauk Co., Wisconsin. 12 October 1984. D.J. Heath! 300 Anodonta califoriensis Lea, 1852 UMMZ:Uncataloged# Snake River near A. Bowler Home, Near Bliss Idaho. 21 August 1962. [Collector unknown]. Anodonta woodiana (Lea, 1834) UMMZ:Uncataloged# Freshwater stream 10 mi. NE of Tam Sui, Taiwan. FM 455. [on primary label a name is given; R.E. Kuntz, U.S. Navy]. Anodontoides Simpson, 1898 Anodontoides ferussacianus (Lea, 1834) OSUM:3 379# River Styx at bridge on Co. Rt. 118 near Wadsworth, Madina Co., Ohio. 23 March 1957. D.G. Myer! OSUM:18275.2* South Branch Phelps Creek at Rt. 322 bridge, 1.5 mi. E of Huntsburg, 5.5 mi. NE of Middlefield, Huntsburg Twp., Geauga Co., Ohio. 23 March 1966. R.E. Jezerinac! OSUM:45235.1“ Southwest Branch Vermillion River at Baseline Rd. bridge, [2.6 mi. S of Greenwich, 16.6 mi. N of Mansfield], Greenwich/Blooming Grove Twp., Huron/Richland Co., Ohio. 14 October 1978. R.E. Bowwers! MAH: 989. 4* Silver Creek, R.M. 4.6, at St. Rt. 15 bridge, 1.5 mi. N of Pioneer, 8.4 mi. NNE of Montpelier, T9S, R2W, Sec. 8/9, Madison Twp., Williams Co., Ohio. 2 October 1986. M.A. Hoggarth! Simpsonaias Frierson, 1914 Simpsonaias ambigua (Say, 1825) UWZY:22658*# Wisconsin River, T8N, R1E, Sec. 5, 9.5 mi. S. of Richland Center, Richland Co., Wisconsin. 16 July 1984. D.J. Heath! [glochidia from UMZY:22662*# and UMZY:22672*# examined] OSUM: 55995* Wisconsin River, T8N, R1E, Sec. 5, N side of river, 100 meters upstream of public boat landing, 9.5 mi. S. of Richland Center, Richland Co., Wisconsin. 20 April 1985. D.J. Heathl Strophitus Rafinesgue, 1820 Strophitus undulatus undulatus (Say, 1817) OSUM:23800.1 Spring River below bridge at Galesburg, 12.7 mi. N of Joplin, T29N, R33W, Sec. 3, Jasper Co., Missouri. 15 March 1964. W.H. Dieffenbach! OSUM:13880# Meramac River at Rt. 19 bridge near Steelville, Crawford Co., Missouri. 19 September 1964. D.H. Stansbery and J.J. Jenkinson! OSUM:28082.2# Vermillion River below dam at St. Rt. 20 bridge at Wakeman, 11.5 mi. E of Norwalk, T4N, R20W, Wakeman Twp., Huron Co., Ohio. 28 September 1968. R.E. Bowers! OSUM:49443* Mississippi River, R.Mi. 635.0, East Channel across from Prairie du Chien, N tip of island above U.S. Rt. 18 bridge, Craford Co., Wisconsin. 21 March 1981. M.E. Havlik et al.I 301 OSUM:52458.4* Ashuelot River 0.4 mi S of Surrey Mountain Dam, [4.3 mi. NNW of Keene], Cheshire Co., New Hampshire. 22 August 1982. K.Wright and J. LeBlanc! MAH:792.1* Fish Creek 0.4 mi. above its mouth at Co. Rt. 49 bridge, 1.1 mi. N of Edgerton, 10.4 mi. W of Bryan, St. Joseph Twp., Williams Co., Ohio. 29 October 1986. D.H. Stansbery, K.G. Borror and M.A. Hoggarth! Strophitus undulatus tennesseensis Frierson, 1927 OSUM:33381.2*# Laurel Creek 0.4 mi. N of Bradford along Va. Rt. 91, 6.3 mi. NE of Saltville, Rich Valley District, Smyth Co., Virginia. 29 September 1971. D.H. Stansbery and W.J. Clench! OSUM:55449* Clinch River, R.Mi. 270.6-270.9, 0.7-1.0 mi. SW of Cleveland, 1.5-1.8 mi. NE of Carbo, Russell Co., Virginia. 3 October 1985. G.T. Watters! Strophitus subvexus (Conrad, 1834) OSUM:36240* Buttahatchie River about 0.5 mi. above its mouth, [12 mi. NNW of Columbus], T16S, R19W, Lowndes Co., Mississippi. 4 October 1974. R. Grace et al.! Pressodonta Simpson, 1900 Pressodonta viridis (Rafinesque, 1820) OSUM:21560# Little Darby Creek at Rosedale-Plain City Rd. bridge, 2.8 mi. E of Rosedale, Pike Twp., Madison Co., Ohio. 19 March 1969. C.B. Stein! OSUM:47 518* Horse Lick Creek, 0.3 mi. below mouth of Raccoon Creek at Dango, 7.6 mi. SW of Mckee, Jackson Co., Kentucky. 28 February 1980. S. call, K. Camburn and G. Fallo! Pressodonta heterodon (Lea, 1829) OSUM:25106.2* Canoe River at old Newland St. bridge, 2.4 5 mi. NNE of Norton, Bristol Co., Massachusetts. 2 June 1969. H.D. Athearn! Pressodonta compressa (Lea, 1829) OSUM:16039.4# Hayworth Creek at bridge 3 mi. SW of Maple Rapids, 5 mi. NE of Fowler, Sec. 19, Essex Twp., Clinton Co., Michigan. 16 April 1966. C.B. Stein! OSUM:23179.1* Little Darby Creek above Rosedale-Plain City Rd. bridge, 2.8 mi. E of Rosedale, Pike Twp., Madison Co., Ohio. 20 October 1969. C.B. Stein, M.E. Fikes et at.! OSUM:27151~ West Branch Cuyahoga River at St. Rt. 87 bridge, 1.9 mi. W of Burton, 8 mi. S of Chardon, Burton Twp., Geauga Co., Ohio. 31 October 1971. C.B. Stein! MAH:702* Big Darby Creek below access point within Battelle-Darby Metro Park, 0.6 mi. S of Georgesville, 3.5 mi. SW of Galloway, Pleasant Twp., Franklin Co., Ohio. 9 September 1985. H.T. Albinl MAH:727* Fish Creek above and below Edon Rd. bridge, 1.9 mi. NW of Edgerton, St. Joseph Twp., Williams Co., Ohio. 2 October 1985. M.A. Hoggarth and D. Rice! 302 Pressodonta subviridis (Conrad, 1835) OSUM:27131.66* Little River at U.S. Rt. 221 bridge, at Woods Store, 5.3 mi. NE of Floyd, 3 3.7 mi. SW of Roanoke, Floyd Co., Virginia. 3 October 1970. D.H. Stansbery and W.J. Clench! [glochidia from OSUM:27131.68* examined] Pressodonta holstonia (Lea, 18 38) OSUM:55826.6* South Fork Clinch River at St. Rt. 61 bridge, E edge of Tazewell, Tazewell Co., Virginia. 13 October 1985. D.H. Stansbery! [glochidia from OSUM:55826.7* examined] Pegias Simpson, 1900 Peqias fabula (Lea, 1838) OSUM:41308.3*# Little South Fork Cumberland River at Freedom Church Ford, 2.0 mi. ENE of Ritner, 14.3 mi. E of Monticello, Wayne Co., Kentucky. 22 October 1977. w. and L. S tarnes! OSUM:41309.1* Little South Fork Cumberland River at Freedom Church Ford, 2.0 mi. ENE of Ritner, 14.3 mi. E of Monticello, Wayne Co., Kentucky. 22 October 1977. A. Bogan! Alasmidonta Say, 1818 Alasmidonta undulata (Say, 1817) OSUM:52434.4* Merrimack River just below Sewalls Fall’s Dam, 2.7 mi. SE of Penacook, 3.7 mi. NNW of Concord, Concord Twp., Merrimack Co., New Hampshire. 31 October 1982. K.E. Wright! Alasmidonta marginata Say, 1818 MAH:277.1* Big Darby Creek at and above McLean Mill Rd. bridge, 0.2 mi SW of Fox, 4.7 mi. NW of Circleville, Jackson Twp., Pickaway Co., Ohio. 1 October 1982. M.A. Hoggarth, G.T. Watters and L.A. Sharpneckl OSUM:53152# Olentangy River just above Powell Rd. bridge, 1.6 mi. E of Powell, 9.8 mi. S of Delaware, T3N, R19W, Delaware Co., Ohio. 29 September 1983. C.B. Stein, W.N. Kasson and N.W. Britt! MAH:724.1*# Fish Creek above and below Edon Rd. bridge, 1.9 mi. NW of Edgerton, St. Joseph Twp., Williams Co., Ohio. 2 October 1985. M.A. Hoggarth and D. Rice 1 Arcidens Simpson, 1900 Arcidens confragosus (Say, 1829) OSUM:52015* Green River at Glenmore below lock 5 dam, 12 mi. N of Bowling Green, Warren Co., Kentucky. 2 November 1977. D.H. Stansbery, K.G. Borror and W.N. Kasson! Lasmiqona Rafinesgue, 1831 Lasmigona coatata (Rafinesque, 1820) OSUM:20550 Big Walnut Creek at U.S. Rt. 36 bridge, 1.7 mi. E of Bainbridge, Sec. 6/7/8, Floyd Twp., Putnam Co., Indiana. 27 November 1968. C.B. Stein! 303 MAH:279.1* Big Darby Creek at and above McLean Mill Rd. bridge, 0.2 mi. SW of Fox, 4.7 mi. NW of Circleville, Jackson Twp., Pickaway Co., Ohio. 1 October 1982. M.A. Hoggarth, G.T. Watters and L.A. Sharpneck! MAH: 585*# Big Darby Creek at access, 0.9 mi. N of Harrisburg, 1.7 mi. NW of Orient, Pleeasant Twp., Franklin Co., Ohio. 27 September 1983. M.A. Hoggarth! MAH:882.1*# Fish Creek at bridge 0.7 mi. W of Arctic, 3.8 mi. NE of Butler, Sec. 20/29, Troy Twp., Dekalb Co., Indiana. 30 October 1985. D.H. Stansbery, K.G. Borror and M.A. Hoggarth! INHS:2 308# Kankakee River at U.S. Rt. 45 bridge, Kankakee Co., Illinois. 14 March 1986. [Collector unknown]. Lasmiqona complanata (Barnes, 1823) OSUM: 51922 Wabash River, w bank, 2.8 mi. N of New Harmony, 2.6 mi. SW of Griffin, T4S, R14W, Sec. 14/23/24, White Co., Illinois. 19 September 1978. J. Christopher and H. Rosenfield! MAH:278.2* Big Darby Creek at and above McLean Mill Rd. bridge, 0.2 mi. SW of Fox, 4.7 mi. NW of Circleville, Jackson Twp., Pickaway Co., Ohio. 1 October 1982. M.A. Hoggarth, G.T. Watters and L.A. Sharpneck! INHS:1923# MacKinaw River at U.S. Rt. 51 [bridge], I.5 mi. SSE of Kappa, McLean Co., Illinois. 17 October 1984. M.J. Wetzel and J.M. Kasprowicz! Ambleminae (Rafinesque, 1820) Morrison, 1955 Magnonaias Utterback, 1915 Maqnonaias nervosa (Rafinesque, 1820) OSUM:13032.66* St. Francis River Bay halfway between Wynne and Perkin, 1.0 mi. S of Rt. 64 bridge. Cross Co., Arkansas. 25 October 1964. C.B. Steinl OSUM:21794# Tennessee River at mile 18, 4 mi. below Kentucky Dam, Marshall/Livingston Co. , Kentucky. November 1968. J. Williams! OSUM:54178* Mississippi River, R.MI. 299.8-301.1, [7.8-9.0 mi SE of Hannibal (MO)], Pike/Ralls Co., Illinois/ Missouri. 16 October 1979. R.B. Lewis et al.I OSUM:178* Licking River, 1.6 mi. E of Butler, immediately above mouth of Flour Creek, 22 mi. SE of Cincinnati, Pendleton Co., Kenkucky. 31 October 1986. D.H. Stansbery et al.! OSUM:1986:22* Green River at Genmore, below Lock 5 Dam, 12.0 mi. N of Bowling Green, Warren Co., Kentucky. 1 November 1986. D.H. Stansbery et al.1 Maqnonaias bovkiniana (Lea, 1840) OSUM:51107.5* Apalachicola River below U.S. Rt. 90 bridge, 1.0 mi. W of Chattahoochee, 17.8 mi. WNW of Quincy, T4N, R6W, Sec. 32, Gadsden Co., Florida. 29 October 1981. D.H. Stansbery et al.l [glochidia from OSUM:51107.4# also examined] 304 Plectomerus Conrad, 183 5 Plectomerus dombeyana (Valenciennes, 1827) OSUM:42011* Black Warrior River at Hall Shoals, below Eutaw Dam, 5.8 mi. SE of Eutaw, Sec. 25, T21N, R2E, Green Co., Alabama. 28-30 July 1975. J.D. Williams, R. Grace and T. Grace! OSUM:53273.2* Calcasieu River at Nevel's Bluff, 2.0 mi. NE of Indian Village, 6.9 mi. WSW of Kinder, 22.0 mi. NE of Lake Charles, Allen Parish, Louisiana. 25 July 1982. D.H. Stansbery and M.A. Hoggarth! [glochidia from OSUM:53 273.3* examined] Tritogonia Agassiz, 1852 Tritoqonia verrucosa (Rafinesque, 1820) MAH:654.1* Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt.) Rd. bridge, 3.4 mi. S of Orient, 15.3 mi. NW of Circleville, Scioto/Darby Twp., Pickaway Co., Ohio. 18 May 1984. M.A. Hoggarth and G.T. Watters! [glochidia from MAH:654.2# examined] Quincuncina Ortmann, 1922 Quincuncina infucata (Conrad, 1834) OSUM:48 537.1* Suwannee River [at Fl. Rt. 51 bridge, 8.4 mi. SSE of Jasper, Sec. 17], Hamilton/Suwannee Co., Florida. 14 May 1978. W.J. Clench et al. ! [glochidia from OSUM:48537.2* examined] Ouadrula Rafinesque, 1820 Quadrula cylindrica cylindrica (Say, 1817) OSUM:26318.11# Glover Creek above St. Rt. 3 and 7 bridge, 2 mi. N of Glover, 11 mi. NW of Broken Bow, T7S, R2E, McCurtain Co., Oklahoma. 23 June 1969. B.D. Valentine and W.R. Suter! Quadrula pustulosa pustulosa (Lea, 1831) OSUM:45174.1# Osage River [at Mo. Rt. 13 bridge] at Osceola, [5.8 mi. S of Lowry City], T38N, R25W, Sec. 17, St. Clair Co., Missouri. 23 July 1977. A.c. Buchananl Amblema Rafinesque, 1820 Amblema plicata plicata (Say, 1817) OSUM:19676.21# Mohican River just above its confluence with the Kokosing River, Newcastle Co., Ohio. 28 July 1967. C.B. Stein and K.A. Heffelfinger! Fusconaia Simpson, 1900 Fusconaia ebena (Lea, 1831) OSUM:3 433 5.112# Tombigbee River about 2 mi. N of Gainsville, about 11.5 mi. N of Epes, Sec. 25, T22N, R2W, Sumter Co., Alabama. 24 June 1972. D.H. Stansbery, J.D. Williams and V. Pearson! 305 Elliptic* Rafinesque, 1820 Elliptio dilatata (Rafinesque, 1820) MAH:946.9* Kalamazoo River above St. Rt. 60 bridge, 3.0 mi. WSW of Spring Arbor, 12.0 mi. WSW of Jackson, Jackson Co., Michigan. 13 May 1986. M.A. Hoggarth! Lampsilinae (Von Ihering, 1901) Ortmann, 1910 Ptychobranchus Simpson, 1900 Ptychobranchus fasciolaris (Rafinesque, 1820) MAH: 586# Big Darby Creek at access 0.9 mi. N of Harrisburg, 1.7 mi. NW of Orient, Pleasant Twp., Franklin Co., Ohio. 27 September 1983. M.A. Hoggarth! MAH:640.1* Little Darby Creek at Co. Rt. 131 bridge (Grewell Rd. ) , 1.8 mi. E of Plumwood, 7.7 mi. NW of West Jefferson, Monroe Twp., Madison Co., Ohio. 11 May 1984. M.A. Hoggarth and G.T. Watters! MAH:651* Little Darby Creek at Little Darby Rd. access, 2.7 mi. SE of Plumwood, 6.4 mi. NW of West Jefferson, Monroe Twp., Madison Co., Ohio. 17 May 1984. M.A. Hoggarth and G.T. Watters! Ptychobranchus occidentalis (Conrad, 1836) OSUM:45361.14* Current River "between Mo. Rt. 106 and Van Buren," [about 19 mi. of stream, Shannon/Carter Co.], Missouri. 24 October 1977. R.D. Oesch! [glochidia from OSUM:45361.17* examined] Ptychobranchus greeni (Conrad, 1834) OSUM:19025.2* Conasauga River above lower Kings Bridge, 5 mi. WNW of Eton, Murray/Whitfield Co., Georgia. 25 September 1966. D.H. Stansbery and H.D. Athearn! Ptychobranchus subtentum (Say, 1825) OSUM:43156.5* Clinch River at mouth of Copper Creek, 1.3 mi. S of Clinchport, 9.3 mi. W of Gate City, Scott Co., Virginia. 21 October 1978. D.H. Stansbery, K.G. Borror et al. ! Obliquaria Rafinesque, 1820 Obliquaria reflexa Rafinesque, 1820 OSUM:54361.1* Mississippi River, R.Mi. 564.5-566.1, about 3.5 mi. SW of Galena (IL), Jo Daviess/Jackson Co., Illinois/Iowa. 7-8 August 1979. R.B. Lewis et al.! Cyproqenia Agassiz, 1852 Cyprogenia stegaria (Rafinesque, 1820) OSUM:6298.21* Green River at Munfordville, Hart Co., Kentucky. 22 October 1961. D.H. Stansbery! Cyproqenia aberti (Conrad, 1850) OSUM:48067*# St. Francis River along Mo. Rt. E, 2.5 mi. NNE of French Mills, 11.5 mi. SW of Fredericktown, SE 1/4, Sec. 3, T32N, R5E, Madison Co., Missouri. 5 October 1977. w.L. Pflieger and T. Grace! 306 Dromus Simpson, 1900 Dromus dromas (Lea, 1834) OSUM:20407.1* Powell River 2.5 mi. ENE of Hoop, 11.5 mi. NE of Tazewell, Clairborne Co., Tennessee. 20 October 1968. G.F. Ahrens! OSUM:23200.9* Powell River at Hoop ("Brooks Bridge"), 9.5 mi. NE of Tazewell, Clairborne Co., Tennessee. 19 October 1969. D.H. stansbery, C.B. Stein, K.G. Borror and J.E. Ditmars! Actinonaias Fischer and Crosse, 1894 Actinonaias liqamentina carinata (Barnes, 1823) MAH: 842.1*# Fish Creek at bridge 2.0 mi. NW of Edgerton, 11.9 mi. W of Bryan, Sec. 20, T6N, R1E, St. Joseph Twp., Williams Co., Ohio. 29 October 1985. D.H. Stansbery, K.G. Borror and M.A. Hoggarth! Actinonaias pectorosa (Conrad, 18 34) OSUM:24337*# Middle Fork Holston River, 3.7 mi. S of Glade Spring at Va. Rt. 91 bridge (Craigs Bridge), Washington Co., Virginia. 16 September 1968. D.H. Stansbery and W.J. Clench! OSUM:48748.3* Clinch River below footbridge at Slant, 7.1 mi. NNW of Gate City, [8.1 mi. ENE of Clinchport, Dekalb Twp.], Scott Co., Virginia. 22 December 1980. C.C. Coney! Obovaria Rafinesque, 1820 Obovaria retusa (Lamarck, 1819) UMMZ:Uncataloged*# Tennessee River (Kentucky Lake) [at] U.S. Rt. 70 bridge [at] New Johnsonville, [Humphreys Co.], Tennessee. October 1958. J. Bates! Obovaria olivaria (Rafinesque, 1820) OSUM:51282.2* Mississippi River, R.Mi. 634.7, at U.S. Rt. 18 bridge, main channel, 1.5 mi. W of Prairie du Chien, Craford Co., Wisconsin. 15 May 1981. M.E. Havlik et al. ! [glochidia from OSUM:51282.3# examined] Obovaria subrotunda (Rafinesque, 1820) MAH:659.2*# Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt. ) Rd. bridge, 3.4 mi. S of Orient, 15.3 mi. NW of Circleville, Scioto/Darby Twp., Pickaway Co., Ohio. 18 May 1984. M.A. Hoggarth and G.T. Watters! MAH:805.1* Fish Creek at Co. Rt. 49 bridge, 0.4 mi. above its mouth, 1.1 mi. N of Edgerton, 10.4 mi. w of Bryan, St. Joseph Twp., Williams Co., Ohio. 29 October 1985. D.H. Stansbery, K.G. Borror and M.A. Hoggarth! Obovaria iacksoniana (Frierson, 1912) OSUM:50233.8* Sipsey River below Rt. 21 bridge, [1.3 mi. W of Brownville, 16.8 mi. NW of Tuscaloosa], Tuscaloosa Co., Alabama. 10 October 1981. L.M. Koch! [glochidia from OSUM:50233.7# examined] Obovaria unicolor (Lea, 1845) OSUM:33158* Sabine River at La. Rt. 8 and Tex. Rt. 3 bridge, 1.3 mi. W of Burr Ferry, Vernon Parish/Newton Co., 307 Louisiana/Texas. 14 July 1968. D.H. Stansbery, C.B. Stein et a l . ! OSUM:47696.6* Pearl River [0.8 mi. SSE of Drysdale, 6.7 mi. SW of Carthage, Sec. 25/36], T10N, R6E, Lake Co., [Mississippi]. 5 October 1979. R.G. Rummel and P. Hartfield! [glochidia from OSUM:47696.3# examined] Ellipsaria Rafinesque, 1820 Ellipsaria lineolata (Rafinesque, 1820) OSUM:1984:14* Ohio River, R.Mi. 443.0-445.0, from 0.4 mi. NW of Moscow (OH) to Point Pleasant (OH), 5.0-6.8 mi. SE of New Richland (OH), Pendleton/Campbell Co., Kentucky. 16 November 1984. D.H. Stansbery, W.N. Kasson, G.T. Watters and M.A. Hoggarth! Leptodea Rafinesque, 1820 Leptodea fraqilis (Rafinesque, 1820) MAH:626.1* Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt.) Rd. bridge, 3.4 mi. S of Orient, 15.3 mi. SW of Columbus, Scioto/Darby Twp., Pickaway Co., Ohio. 13 April 1984. M.A. Hoggarth and G.T. Watters! MAH:658# Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt.) Rd. bridge, 3.4 mi. s of Orient, 15.3 mi. NW of Circleville, Scioto/Darby Twp., Pickaway Co., Ohio. 18 May 1984. M.A. Hoggarth and G.T. Watters! Leptodea ochracea (Say, 1817) MAH:896* Great Herring Pond at Carter's Brook Rd. , 4.0 mi. NNE of Buzzards Bay, 3.0 mi. NW of Sagamore, Plymouth Co., Massachusetts. 31 July 1985. G.T. Watters, W.N. Kasson and K. Wright! Lastena Rafinesque, 1820 Lastena ohiensis (Rafinesque, 1820) OSUM:54520.1* Big Blue River below bridge [3.0 mi. NNW of Barneston] , 4.0 mi. SE of Wymore, [T2N, R7E] , Gage Co., Nebraska. 7 September 1981. F.E. Hoke! Lastena amphichaena (Frierson, 1898) OSUM: 33163.13* Sabine River at La. Rt. 8 and Tx. Rt. 9 bridge, 1.3 mi. w of Burr Ferry, Vernon Parish / Newton Co., Louisiana/Texas. 14 July 1968. D.H. Stansbery, C.B. Stein et. a l . ! Potamilus Rafinesque, 1818 Fotamilus alatus (Say, 1817) OSUM:1983:58*# Muskingum River, R.Mi. 31.8-33.4, 1.4 mi. N of Luke Chute Lock and Dam, 4.3 mi. W of Beverly, Windsor/Waterford Twp., Morgan/Washington Co., Ohio. 25 September 1983. W.N. Kasson and K. Perkins! OSUM:55465* Clinch River, R.Mi. 213.0 at Clinchport, just above swinging bridge, Scott Co., Virginia. 5 October 1985. G.T. Watters! 308 Potamilus purpuratus (Lamarck, 1819) OSUM:15738.2* Brazos River at foot of Whitney Dam, about 20 mi. NW of Waco, Bosque/Hill Co., Texas. 20 March 1966. C.B. Stein! OSUM:52335.4# [Colorado River at Buchanan Impoundment], at LCRA Cedar Point Park, [2.3 mi. SSE of Tow, 15.9 mi. NE of Llano, Llano Co., Texas]. 29 April 1971. [L.J. Bottimer]! Medionidus Simpson, 1900 Medionidus conradieus (Lea, 1834) OSUM:55466# Clinch River, R.Mi. 270.6-270.9, 0.7-1.0 mi. SW of Cleveland, 1.5-1.8 mi. NE of Carbo. Russell Co., Virginia. 3 October 1985. G.T. Watters! Liqumia Swainson, 1840 Ligumia recta (Lamarck, 1819) OSUM:1984:2* Mississippi River, R.Mi. 635.6, E channel, 1.1 mi. NW of Prairie du Chien, Crawford Co., Wisconsin. 29 April 1984. D.H. Stansbery, M. Havelik et al.! Venustaconcha Thiele, 1934 Venustaconcha ellipsiformis ellipsiformis (Conrad, 1834) UMMZ:Uncataloged# South Branch Cranberry Creek at Byron, Shiawassee Co., Michigan. 21 October 1960. Heard and Van der Schalie! UMMZ:Uncataloged# Bruce Creek approximately 2 mi. N of Red Bay, Walton Co., Florida. 24 April 1963. [collector unknown]. MAH:947.2* Kalamazoo River above St. Rt. 60 bridge, 3.0 mi. WSW of Spring Arbor, 12.0 mi. WSW of Jackson, Jackson Co., Michigan. 13 May 1986. M.A. Hoggarth! Villosa Frierson, 1927 Villosa trabalis (Conrad, 1834) OSUM:9516.49* Rockcastle River, Rt. 80 W of London, RockcaStle/Laurel Co., Kentucky. 26 October 1963. C.B. Stein and D.H. Stansbery! Villosa perpurpurea (Lea, 1861) OSUM:16262* Clinch River at St. Rt. 460 bridge at Richlands, Tazewell Co., Virginia. 6 October 1965. D.H. Stansbery and J.J. Jenkinson! Villosa villosa (Wright, 1898) OSUM:45940.3* Santa Fe River at U.S. Rt. 41/441 bridge, [2.0 mi. NNW of High Spring, 27.3 mi. NW of Gainsville, Sec. 27/28] Alachua/Columbia Co., Florida. 4 August 1975. J.M. Condit and E.P. Keferl! [glochidia from OSUM:45940.7* examined] Villosa Vibex (Conrad, 1834) UMMZ:Uncataloged# [Hillsborough River at] Hillsborough River State Park, Florida. 24 October 1962. [collector unknown]. 309 UMMZ:Uncataloged# Bruce Creek approximately 2 mi. N of Red Bay, Walton Co., Florida. 24 April 1963. [Collector unknown]. OSUM:54631* Yellow River [at U.S. Rt. 84 bridge, 3.0 mi. SE of Sanford], 5.0 mi. W of Opp, Sec. 33, T4N, R17E, Covington Co., Alabama. 2 June 1969. Hector Harima and Ben w a l l ! OSUM:24124* Santa Fe River at U.S. Rt. 27 bridge, 2.5 mi. NW of High Springs, 7.5 mi. SE of Fort white, Columbia/Alachua Co., Florida. 24 February 1970. J.J Jenkinsont OSUM:48628* "Nichols Cr." Monroe Co., Mississippi, [in the Tombigbee River drainage (-> Mobile River)]. 18 March 1972. [Collector unknown (ex. J.D. Williams)] Villosa iris iris (Lea, 1829) UMMZ:Uncataloged# River Rasin at Sharon Hollows, Washington Co., Michigan. 13 May 1961. [Collector unknown]. MAH:641.1* Little Darby Creek at Co. Rt. 131 bridge (Grewell Rd.), 1.8 mi. E of Plumwood, 7.7 mi. NW of West Jefferson, Monroe Twp., Madison Co., Ohio. 11 May 1984. M.A. Hoggarth and G.T. Watters 1 MAH:664# Little Darby Creek at U.S. Rt. 40 bridge, 0.4 mi. ENE of West Jefferson, 14.5 mi. W of Columbus, Jefferson Twp., Madison Co., Ohio. 12 May 1984. D.H. Stansbery, M.A. Hoggarth and Animal Ecology Class 1 OSUM:55828.3* South Fork Clinch River at Fourway, at E edge of Tazewell, at U.S. Rt. 19 bridge, Tazewell Co., Virginia. 13 October 1985. D.H. Stansbery! [glochidia from OSUM:55828.4* examined] Lampsilis Rafinesque, 1820 Lampsilis teres teres (Rafinesque, 1820) OSUM:36409* Tombigbee River 0.5 mi. below mouth of Luxaplilla Creek, [3.2 mi. S of Columbus], Sec. 32/5, T18S, R18W, Lowndes Co., Mississippi. 5 October 1974. R. Grace and T. Whitfields! OSUM:36531.1* Whitewater River at Bollinger Mill Dam, at Burfordville, T31N, RUE, Cape Girardeau Co., Missouri. 17 October 1974. F. Schilling and H. Kemper! OSUM:51669.2* Mississippi River, R.Mi. 632.1, E. Shore main channel [2.9 mi. SW of Prairie du Chien], Craford Co., Wisconsin. 10 June 1981. D.J. Heath and M.C. Weisensel! UWZY:25024.1# Wisconsin River 9.5 mi. S of Richland Center, Sec. 5, T8N, RlE, Richland Co., Wisconsin. 9 July 1983. D.J.Heath 1 Lampsilis teres anodontoides (Lea, 1831) OSUM:35612* Uphapee Creek at 1-85 bridge, 3.4 mi. N of Tuskegee, 6.3 mi. S of Notasulga, Sec. 7, T17N, R24E, Macon Co., Alabama. 4 April 1968. J.S. Ramsey and Ichthyology Class! OSUM:41762.2* St. Francis River 2.2 mi. N of Parkin, 33.0 mi. WNW of Memphis (TN), Sec. 21, T8N, R5E, Cross Co., 310 Arkansas. 14 March 1978. D.H. Stansbery, R. Grace and M. S m i t h 1 Lampsilis australis Simpson, 1900 OSUM:45206.2* Yellow River at Al. Rt. 55 bridge, 9.0 mi. NW of Florala, 15.0 mi. s of Andalusia, Covington Co., Alabama. 14 October 1972. H. Harima and B. Wall 1 Lampsilis radiata radiata (Gmelin, 1791) MAH:897.1*# Great Herring Pond at Carter’s Brook Rd. 4.0 mi. NNE of Buzzards Bay, 3.0 mi. NW of Sagamore, Plymouth Co., Massachusetts. 31 July 1985. G.T. Watters, W.N. Kasson and K. Wright! [glochidia from MAH:897.2# examined). Lampsilis radiata luteola (Lamarck, 1819) MAH:321.6* Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt. ) Rd. bridge, 3.4 mi. S of Orient, 15.3 mi. SW of Columbus, Scioto/Darby Twp., Pickaway Co., Ohio. 7 January 1983. M.A. Hoggarth and G.T. Watters I MAH: 587.1* Big Darby Creek at access 0.9 mi. N of Harrisburg, 1.7 mi. NW of Orient, Pleasant Twp., Franklin Co., Ohio. 27 September 1983. M.A. Hoggarth! MAH:628.1* Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt. ) Rd. bridge, 3.4 mi. S of Orient, 15.3 mi. SW of Columbus, Scioto/Darby Twp., Pickaway Co., Ohio. 13 April 1984. M.A. Hoggarth and G.T. Watters! MAH:652* Little Darby Creek at Little Darby Rd access, 2.7 mi. SE of Plumwood, 6.4 mi. NW of West Jefferson, Monroe Twp., Madison Co., Ohio. 17 May 1984. M.A. Hoggarth and G.T. Watters! MAH:721.2* Fish Creek at St. Rt. 49 bridge, 0.4 mi. above its mouth, 1.1 mi. N of Edgerton, 10.4 mi. W of Bryan, St. Joseph Twp., Williams Co., Ohio. 1 October 1985. M.A. Hoggarth and D. Ricel MAH: 845# Fish Creek at bridge 2.0 mi. NW of Edgerton, 11.9 mi. W of Bryan, Sec. 20, T6N, R1E, St. Joseph Twp., Williams Co., Ohio. D.H. Stansbery, K.G. Borror and M.A. Hoggarth! Lampsilis straminea claiborensis (Lea, 1838) OSUM:36743* Tombigbee River at island about 0.2 mi. above Warsaw, 7.8 mi. NNW of Gainesville, Sec. 28, T23N, R2W, Sumter Co., Alabama. 8 June 1972. J.D. Williams et al.! OSUM:36273.13* Ellis Creek at St. Rt. 69 bridge, 7.8 mi. SE of Columbus, 17.7 mi. E of Artesia, Sec. 17, T19S, R17W, Lowndes Co., Mississippi. 10 June 1972. J.D. Williams and C. Pearson! [glochidia from 36273.14* examined) Lampsilis abrupta (Say, 1831) OSUM: 13303* Gasconade River 3 mi. N of Mount Sterling, Gasconade Co., Missouri. 17 September 1964. D.H. Stansbery and J.J. Jenkinson! OSUM:38841* Kanawha River immediately below Kanawha Falls, 0.3 mi. SSE of Glen Ferris, 1.4 mi. SW of Gauley Bridge, Falls Twp., Fayette Co., West Virginia. 27 November 1976. K.G. Borror, P.H. Borror, K.B. Sprinzl and A. Sprinzl! 311 Lampsilis higginsi (Lea, 1857) OSUM:49024. 1* Mississippi River, R.Mi. 633.3, E channel, N end of Indian Isle, [2.1 mi. SW of Prairie du Chien, Sec. 1/2], T6N, R7W, Craford Co., Wisconsin. 11 November 1980. A. Reed (donor: M.E. Havlik)I Lampsilis rafinesgueana Frierson, 1927 OSUM:36319.7* Spring River just below St.Rt. 43 bridge, 1.5 mi. ESE of Galesburg, 11.7 mi. NW of Carthage, Sec. 1/2, T29N, R32W, Lowndes Co., Mississippi. 10 June 1974. F. Schilling and H. Kemper! Lampsilis ornata (Conrad, 1835) OSUM:54661* Amite River 1 mi. NNW of Denham Springs, [about 13 mi. WNW of Livingston, T6S, R3E, Ward 2], Livingston Parish, Louisiana. 1 October 1967. E.N. Lambremont et al.! Lampsilis satura (Lea, 1858) OSUM:38973.51* West Fork San Jacinto River below 1-45 bridge, 4.5 mi. S of Conroe, 36 mi. N of Houston, Montgomery Co., Texas. 20 July 1968. D.H. Stansbery et al.! [glochidia from OSUM:3897 3.52* examined] Lampsilis ovata (Say, 1817) OSUM:43164.1* Clinch River above mouth of Copper Creek, 1.3 mi. S of Clinchport, 9.3 mi. W of Gate city. Scoot Co., Virginia. 21 October 1978. D.H. Stansbery, K.G. Borror et. al.! Lampsilis ventricosa (Barnes, 1823) OSUM:44619* Green River below Lock 5 dam at Glenmore, 12 mi. N of Bowling Green, Warren Co., Kentucky. 21 October 1979. D.H. Stansbery, W. Sage et al.! OSUM:55976# Olentangy River just above Powell Rd. bridge, 1.6 mi. E of Powell, 9.8 mi. S of Delaware, T3N, R19W, Delaware Co., Ohio. 29 September 1983. C.B. Stein, W.N. Kasson and N.W. Britt! MAH: 846.1* Fish Creek at bridge 2.0 mi. NW of Edgerton, 11.9 mi W of Bryan, Sec. 20, T6N, R1E, St. Joseph Twp., Williams Co., Ohio. 29 October 1985. D.H. Stansbery, K.G. Borror and M.A. Hoggarth! MAH: 954.1* Sugar River 300 m downstream of Lake Belle View Dam, 150 m upstream of St. Rt. 69 bridge, at Belleville, Sec. 34, T5N, R8E, Dane Co., Wisconsin. 15 May 1986. M.A. Hoggarth and D.J. Heath! [glochidia from MAH:954.2*, MAH:954.3*, MAH:954.4*, MAH:954.5* and MAH:954.6* examined] Lampsilis reeviana brevicula (Call, 1887) OSUM:45363.20* Current River "between Mo. Rt. 106 and Van Buren," [about 9 mi. of stream. Shannon/Carter Co.,] Missouri. 24 October 1981. R.D. Oeschl [glochidia from OSUM:45363.22*, OSUM:45363.35* and OSUM:45363.50* examined] Lampsilis crocata (Lea, 1841) OSUM:54485.1* Tar River at U.S. Rt. 64 bridge, 2.4 mi. SW of Spring Hope, [10.8 mi. mi. WSW of Nashville, Nash 312 Co.,] Tennessee. 1973. M. Imlayl [glochidia from OSUM:54485.2* examined] OSUM:42060.1* Waccamaw River just below Lake Waccamaw Dam, 6.2 mi. SE of Hallsboro, 11.7 mi. ESE of Whiteville, Columbus Co., North Carolina. 21 July 1978. D.H. Stansbery et a l . 1 Lampsilis cariosa (Say, 1817) OSUM: 54500* Tar River at U.S. Rt. 15 bridge, [2.7 mi. SW of Clay, 6.7 mi. SSW of Oxford, Granville Co.,] North Carolina. 1973. M. Imlay! Lampsilis fasciola Rafinesque, 1820 OSUM:25467*# Kanawha River immediately below Kanawha Falls, 1.2 mi. below Gauley Bridge, Falls Twp., Fayette Co., West Virginia. 1 October 1970. D.H. Stansbery and W.J. Clench! MAH: 562.3* Big Darby Creek at and above Scioto-Darby (Mt. Sterling-Commercial Pt.) Rd. bridge, 3.4 mi. S of Orient, 15.3 mi. SW of Columbus, Scioto/Darby Twp., Pickaway Co., Ohio. 19 August 1983. M.A. Hoggarth! OSUM:55977* Olentangy River just above Powell Rd. bridge, 1.6 mi. E of Powell, 9.8 mi. S of Delaware, T3N, R19W, Delaware Co., Ohio. 29 September 1983. C.B. Stein, W.N. Kasson and N.W. Britt! OSUM:55033.2* Clinch River, R.Mi. 269.7, 1.0 mi. above Carbo, [1.8 mi. W of Cleveland, 6.2 mi. NW of Lebanon, Castlewood Twp.,] Russell Co., Virginia. 26 July 1985. D.H. Stansbery and C.B. Stein! Lampsilis altilis (Conrad, 1834) OSUM:34764. 1* Chewacla Creek 1.8 mi. SE [4 mi. S] of Auburn, [8.2 mi. SW of Opelika], Sec. 17, T18N, R26E, Lee Co., Alabama. 10 March 1973. J.C. Hurd! [glochidia from OSUM:34764.7# examined] Lampsilis perovalis (Conrad, 1834) OSUM:50239.2* Sipsey River below Rt. 21 bridge, [1.3 mi. W of Brownsville, 16.8 mi. NW of Tuscaloosa], Tuscaloosa Co., Alabama. 10 October 1981. L.M. Kochi Epioblasma Rafinesque, 1831 Epioblasma triguetra (Rafinesque, 1820) MAH: 588.1* Big Darby Creek at access 0.9 mi. N of Harrisburg, 1.7 mi. NW of Orient, Pleasant Twp., Franklin Co., Ohio. 27 September 1983. M.A. Hoggarth! [glochidia from MAH:588.2# examined] MAH:631.1* Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt. ) Rd. bridge, 3.4 mi. S of Orient, 15.3 mi. SW of Columbus, Scioto/Darby Twp., Pickaway Co., Ohio. 13 April 1984. M.A. Hoggarth and G.T. Watters! MAH:700.1# Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt.) Rd bridge, 3.4 mi. S of Orient, 15.3 mi. SW of Columbus, Scioto/Darby Twp., Pickaway Co., Ohio. 6 September 1985. M.A. Hoggarth! 313 Epioblasma brevidens (Lea, 1831) OSUM:16173* Cedar Creek about 1 mi. SE of Mingo at bridge, Tishomingo Co., Mississippi. 5 November 1965. P. Yokley and B.G. Isoms! OSUM:203 80.91# Clinch River between mouth of Possum Trot Run and Brooks Island, 5 mi. ENE of Sneedville, Hancock Co., Tennessee. 24 October 1967. D.H. Stansbery and R.A. Tubbs! Epioblasma metastriata (Conrad, 1840) OSUM:27506.2# Cahaba River above U.S. Rt. 82 and St. Rt. 25 bridge at Centerville, T23N, R9E, Bibb Co., Alabama. 29 September 1968. J.J. Jenkinson! Epioblasma othcalooqensis (Lea, 1857) OSUM:19032.2# Conasaga River above Lower Kings bridge, 5 mi. WNW of Eton, Murray/Whitfield Co., Georgia. 25 September 1966. D.H. Stansbery and H.D. Athearn! Epioblasma lenior (Lea, 1843) OSUM:15584.4# Stones River above Couchville Pike bridge, 1.2 mi. w of Couchville, Davidson Co., Tennessee. 14 October 1965. D.H. Stansbery and J.J Jenkinson! Epioblasma capsaeformis (Lea, 1834) OSUM:3964.5# Clinch River "near Sneedville", [1.0 mi. S of Sneedville, 2.0 mi. N of Duck Creek], Hancock Co., Tennessee. 7 June 1975. H.T. Boschung and T.S. Jandebeur! OSUM:42007*# Clinch River at Clinchport, above swinging bridge, 2.3 mi. N of Speer's Ferry, Scoot Co., Virginia. 2 July 1978. C.R. Ciola and K.L Ciola! OSUM:4 3166# Clinch River above mouth of Copper Creek, 1.3 mi. s of Clinchport, 9.3 mi. W of Gate City, Scott Co., Virginia. 21 October 1978. D.H. Stansbery, K.G. Borror et al.! Epioblasma walkeri (Wilson and Clark, 1914) OSUM:15595.51# Stones River above Couchville Pike bridge, 1.2 mi. w of Couchville, Davidson Co., Tennessee. 14 October 1965. D.H, Stansbery and J.J. Jenkinson! Epioblasma torulosa ranqiana (Lea, 1839) MAH:63 2.1*# Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt. ) Rd. bridge, 3.4 mi. S of Orinet, 15.3 mi. SW of Columbus, Scioto/Darby Twp., Pickaway Co., Ohio. 13 April 1983. M.A. Hoggarth and G.T. Watters 1 MAH:701* Big Darby Creek at Scioto-Darby (Mt. Sterling-Commercial Pt.) Rd. bridge, 3.4 mi. s of Orient, 15.3 mi. SW of Columbus, Scioto/Darby Twp., Pickaway Co., Ohio. 6 September 1985. M.A. Hoggarth! APPENDIX C Data Used To Construct Figures 4 - 8 314 315 Table 5. Morphometric data from glochidia examined with scanning electron microscopy. Each entry represents an average from the glochidia examined from a single female unionid rounded to the nearest 10 um. Species Catalog # Abr Len Hei Hin Lig Pos U. e. alaucinus M A H :2055 Ueg 230 220 170 60 41 A. cvernea OSUM:20911.1 Acy 350 350 270 80 43 A. anatina OSUM:20912.1 Aanl 350 350 260 90 38 OSUM:20912.2 Aan2 360 360 280 100 42 A. berinaiana OSUM:3711.1 Abe 290 290 210 60 30 A. kennerlvi OSUM:52882.2 Akel 350 340 260 90 40 OSUM:52882.3 Ake2 350 350 250 80 40 A. g. grandis OSUM:38467.10 Aggl 360 360 250 90 41 INHS:2247 Agg2 350 350 250 90 42 A. g. corpulenta OSUM:47890 Acol 350 370 270 — — OSUM:53653 Aco2 340 360 260 90 45 A. c. cataracta OSUM:52462.27 Acal 370 350 280 100 41 OSUM:52462.35 Aca2 380 370 290 100 43 A. c. marginata OSUM:38962.6 Ama 360 370 280 110 42 A. doliaris OSUM:26405 Ado 360 340 270 100 40 A. implicate OSUM:5246 3.7 Aip 340 350 160 80 46 A. suborbiculata OSUM:13634 Asu 330 320 230 100 45 A. imbecillis OSUM:9436.2 Aiml 300 300 250 90 41 MAH:435 Aim2 290 290 240 90 44 UWZY:24971.1 Aim3 310 300 260 90 42 A. ferussacianus OSUM:18275.2 Af el 320 320 230 90 41 MAH:989.4 Afe2 320 320 230 90 46 S . ambigua UWZY:22658 Sami 250 260 160 60 43 UWZY:22662 Sam 2 260 260 170 60 47 OSUM:55995 Sam3 250 250 160 60 45 S. u. undulatus OSUM:49443 Sunl 370 300 270 — — OSUM:52458.4 Sun2 360 290 270 90 43 MAH:792.1 Sun 3 360 290 280 100 44 S. tennesseensis OSUM:55449 Ste 350 300 270 90 47 S . subvexus OSUM:36240 Ssu 350 290 270 80 40 P. viridis OSUM:47518 Pvi 310 250 250 80 42 p . heterodon OSUM:25106.2 Phe 330 270 260 80 42 P. compressa OSUM:23179.1 Pcml 320 280 230 80 46 M A H :702 Pcm2 320 280 230 80 46 MAH:727 Pcm3 330 290 240 80 48 P. subviridis OSUM:27131.66 Psul 380 320 250 90 42 OSUM:27131.68 Psu2 370 310 260 90 40 P. holstonia OSUM:55826.6 Pho 290 280 230 70 38 P. fabula OSUM:41308.3 Pfbl 390 330 210 70 48 OSUM:41309.1 Pfb2 390 320 200 70 45 A. undulata OSUM:52434.4 Aun 350 370 250 90 40 A. marginata M A H :277.1 Arml 340 370 230 70 40 MAH:724.1 Arm2 340 370 220 60 41 316 Table 5. Continued Species Catalog # Abr Len Hei Hin Lig Pos A. confraqosus OSUM:52015 Aco 360 350 250 70 42 L. costata MAH:585 Lcsl 340 360 240 80 45 MAH:882.1 Lsc2 340 370 250 80 45 r . complanata MAH:278.2 Leo 290 300 200 60 42 M. nervosa OSUM:13032.66 Mnel 260 340 150 60 42 OSUM:54178 Mne2 260 350 150 60 42 OSUM:178 Mne3 250 340 150 60 43 M. boykiniana OSUM:51107.5 Mbo 250 350 150 —— P . dombeyana OSUM:42001 Pdol 220 250 130 50 40 OSUM:53273.2 Pdo2 230 250 130 50 38 OSUM:53273.3 Pdo3 220 250 130 50 42 T. verrucosa M A H :654.1 Tve 90 100 40 30 47 0 - infucata OSUM:48737.1 Qinl 240 280 100 60 48 OSUM:48737.2 Qin2 230 270 100 50 47 E. dilatata M A H :946.9 Edi 420 220 140 50 43 P. fasciolaris M A H :640.1 Pfal 170 190 80 40 48 M A H :651 Pfa2 170 180 90 40 49 P. occidentalis OSUM:45361.14 Pocl 200 240 100 50 46 OSUM:45361.17 Poc2 200 230 100 40 47 P. greeni OSUM:19025.2 Pgr 190 230 90 50 48 P . subtentura OSUM:43156.5 Psb 190 240 90 40 48 O. reflexa OSUM:54361.1 Ore 220 240 130 60 46 C. stegaria OSUM:6298.21 Cst 210 170 120 40 45 C. aberti OSUM:48067 Cab 210 150 130 30 46 D. dromas OSUM:20407.1 Ddrl 220 110 160 40 45 OSUM:23200.9 Ddr 2 230 120 180 40 45 A. 1. carinata MAH:842.1 Ali 220 240 120 60 46 A. pectorosa OSUM:24337 Apel 240 260 140 60 45 OSUM:48748.3 Ape 2 250 270 150 60 46 O. retusa UMMZ:Uncataloged Obr 220 280 120 50 45 O. olivaria OSUM:51282.2 Ool 200 260 110 40 45 o . subrotunda MAH:659.2 Osul 180 200 90 40 47 MAH:805.1 Osu2 170 210 80 40 50 O. iacksoniana OSUM:50233.8 Oja 180 240 100 40 46 o. unicolor OSUM:33158 Ounl 180 230 90 30 44 OSUM:47696.6 Oun2 170 220 90 30 47 E. lineolata OSUM:1984:14 Eli 240 320 90 40 48 L. fragilis MAH:626.1 Lfr 70 80 30 10 45 L. ochracea MAH:896 Loc 240 290 110 40 48 L. ohiensis OSUM: 54520.1 Loh 120 180 50 20 50 L . amphichaena OSUM:33163.13 Lam 120 180 40 20 49 P. alatus OSUM:1983:58 Pall 220 390 110 40 44 OSUM:55465 Pal2 230 380 100 40 44 P. purpuratus OSUM:15738.2 Ppu 200 350 110 40 46 L. recta OSUM:1984: 2 Lre 210 260 110 40 45 49 47 50 48 48 50 49 45 45 — 44 43 49 48 43 46 41 37 48 50 44 47 46 45 47 49 45 45 47 47 49 45 46 43 — 50 48 46 44 50 48 46 45 317 Pos 30 50 50 — 40 40 50 30 40 40 40 4030 43 5040 42 40 30 40 40 40 30 40 40 40 — 40 40 40 40 40 40 40 40 50 50 50 40 50 Lig 90 100 110 110 110 30 110 110 110 40 100 100 120 40 100 40 110 40 120120 50 100 130 110 40 120 100 120 Hin 100 110 110 100 120 110 120 120 300 300 300 310 290 270 290 280 300 120 300 110 260 300 110 260 300 260 110 250 Hei 270 250 100 280 290 120 250 270 290 270 100 260 240 100 270 100 260 270 280 290 270 120 270 100 300 120 280 300 290 120 300 290 110 290 230 210 240 220 300 220 165 240 230 190 250 190 260 220 230 240 210 190 Len 210 230 200 230 240 220 200 260220 100 200 210 230 260 430 240 250 250 240 280 100 240 240 280 240 240 240 Abr Lte2 Vpu Vvil Lanl Vvll Lte3 Lan2 200 Vel Llu2Llu3 230 Lcl3 190 Lrd Vir2 Lon Lab2 Llu4 Lcl2 Vvi3 Virl Lvel Lsa2Lov 220 Lra 200 Vvl2 Lve2 Lve3 Lve4 Lve5 Lbr2 240 Lbrl Lve6 Lve7 Lcr2 Lbr3 Lbr4 230 Catalog # MAH:947.2 OSUM:9516.49 Vtr OSUM:24124 Vvi2 OSUM:45940.7 OSUM:54631 OSUM:45940.3 M A H :664 OSUM:55828.3 Vir3 OSUM:48268 31.1 5 6 3 O S U M : O S U M :3 5 612 O5 S U M :3 OSUM:51669.2 MAH:641.1 MAH:897.1 MAH:321.6 Llul OSUM:36409 Ltel OSUM:49024.1 Lhi OSUM:36743OSUM:38841 LCll MAH:628.1 MAH:721.2 OSUM:36273.13 OSUM:41762.2 OSUM:38973.52 OSUM:13303 Labi4.1 O316 S U M :4 OSUM:36273.14OSUM:36319.7 M A H : 587.1 M A H :954.1 OSUM:38973.51 Lsal M A H :954.2 MAH:846.1 OSUM:45363.20 M A H :954.5 M A H :954.6 OSUM:54485.1 Lcrl OSUM:54485.2 M A H :954.3 M A H :954.4 OSUM:45363.22 OSUM:45363.35 OSUM:45363.50 trabalis i . i . iris cies perpurpurea OSUM:16262 villosa ellipsiformis vibex r. radiata r. luteola t. t. teres anodontoides satura abrupta rafinesaueana higginsi claiborensis ventricosa ovata r. r. brevicula crocata ornata OSUM:54661 2 Table 5. Continued >I>I>I>1 >1 >1 iJI JUI JWWI JUI 318 Table 5. Continued Species Catalog # Abr Len Hei Hin Lig Pos OSUM:4 2 0 6 0.1 Lcr3 240 290 110 L. cariosa OSUM:54500 Lea 240 310 110 — — L. fasciola OSUM:25467 Lfal 250 300 120 40 50 M A H :562.3 Lfa2 240 290 110 — — OSUM:55033.2 Lfa3 240 290 110 — — L. altilis OSUM:34764.1 Lai 220 270 110 40 47 L. perovalis OSUM:50239.2 Lpe 210 280 110 — — E. triquetra MAH:588.1 Etr 210 210 150 50 44 E. brevidens OSUM:1617 3 Ebr 220 210 150 50 45 E. capsaeformis OSUM:42007 Eca 250 230 160 60 46 E. t. ranqiana MAH:632.1 Eral 250 220 170 60 46 MAH:701 Era2 240 230 160 60 46 Abr, Taxa abbreviation; Len, Length; Hei, Height; Hin, Hinge Length; Lig, Ligament Length; Pos, Position of the Hinge Ligament (% distance from posterior boarder of hinge); data not available. APPENDIX D Binary Data Base 319 320 Table 6. Binary data from glochidia examined with scanning electron microscopy. Taxa 1 - >2->3->4>5>6------>7 >8->9--- >10 >11->12->13-----> ______abcabcabcabababcdefghiiklababcabcdeabcabcdabcdabcdefg Ueg 01001001001100000000100001010001000100100001000100000 Acy 00100100101100000000100001010000100100100001000001000 Aanl 00100100101100000000100001010000100100100001000000100 Aan2 00100100101100000000100001010000100100100001000000100 Abe 00101000101100000000100001010000100100100001000001000 Akel 00100100101100000000100001010000100100100001000100000 Ake2 00100100101100000000100001010000100100100001000100000 Agr1 00100100101100000000100001010000100100100001000001000 Agr2 00100100101100000000100001010000100100100001000001000 Acol 001001001----- 0000000100001010000100100100001000001000 Aco2 00100100101010000000100001010000100100100001000001000 Acal 00100100101100000000100001010000100100100001000001000 Aca2 00100100101100000000100001010000100100100001000001000 Ama 00100100101100000000100001010000100100100001000001000 Ado 00100100101100000000100001010000100100100001000001000 Aip 00100101001010000000010001010001000100100001000100000 Asu 00101000101010000000100001010001000100100001000000001 Aiml 00101000101100000000100001010000100100100001000000010 Aim2 00101000101100000000100001010000100100100001000000010 Aim3 00101000101100000000100001010000100100100001000000010 Afel 00101000101100000000100001010000010100100001000001000 Afe2 00101000101010000000100001010000010100100001000001000 Sami 01001001001100000000100001010001000100100001000100000 Sam2 01001001001010000000100001010001000100100001000100000 Sam3 01001001001010000000100001010001000100100001000100000 Sunl 001010001----- 0000000000101010000010100100001000001000 Sun2 00101000101100000000000101010000010100100001000001000 Sun3 00101000101100000000000101010000010100100001000001000 Ste 00101000101010000000000101010000010100100001000001000 Ssu 00101000101100000000000101010000010100100001000001000 Pvi 00101000101100000000000101010000010100100001000001000 Phe 00101000101100000000000101010000010100100001000001000 Pcml 00101000101010000000000101010000010100100001000001000 Pcm2 00101000101010000000000101010000010100100001000001000 Pcm3 00101000101010000000000101010000010100100001000001000 Psul 00101000101100000000000101010000010100100001000001000 Psu2 00101000101100000000000101010000010100100001000001000 Pho 00101000101100000000000101010000010100100001000000010 Pfbl 00101000101010000000000011010000010100100001000000010 Pfb2 00101000101010000000000011010000010100100001000000010 Aun 00100100101100000000001001010000001100100001000110000 Arml 00100100101100000000001001010000001100100001000101000 Arm2 00100100101100000000001001010000001100100001000100000 Aco 00100100101100000000001001010000001100100001000010000 Lcsl 00100100101010000000001001010000001100100001000110000 321 Table 6. Continued Taxa 1->2->3->4 >5 >6------>7 >8->9--- >10 >11 - >12->13---- > ______abcabcabcabababcdefqhiiklababcabcdeabcabcdabcdabcdefq Lcs 2 00100100101010000000001001010000001100100001000110000 Leo 00101000101100000000001001010000001100100001000010000 Mnel 01000101001101000000000001010010000100001010000000010 Mne2 01000101001101000000000001010010000100001010000000010 Mne3 01000101001101000000000001010010000100001010000000010 Mbo 010001010----- 1000000000001010010000100001010000000010 Pdol 01001001010101000000000001010010000100001010000001000 Fdo2 01001001010101000000000001010010000100001010000001000 Pdo3 01001001010101000000000001010010000100001010000001000 Tve 10010010010011000000000001010010000100100010001000000 Qinl 01001001010101000000000001010010000001001010001000000 Qin2 01001001010011000000000001010010000001001010001000000 Edi 01001001010101000000000001010010000100001010000001000 Pfal 01001001010011000000000001010010000100100010000001000 Pfa2 01001001010011000000000001010010000100100010000001000 Pocl 01001001010011000000000001010010000100100010000001000 Poc2 01001001010011000000000001010010000100100010000001000 Pgr 01001001010011000000000001001010000100100010000001000 Psb 01001001010011000000000001001010000100100010000001000 Ore 01001001001010010000000001010010000100100010000100000 Cst 01001001010100010000000001010010000100100010000001000 Cab 01001001010010010000000001010010000100100010000001000 Ddrl 01010001010010000100000001010010000100100010000100000 Ddr2 01010001010010000100000001010010000100100010000100000 Ali 01001001001011000000000001001010000100001010000100000 Apel 01001001001011000000000001001010000100001010000100000 Ape2 01001001001011000000000001001010000100001010000100000 Obr 01001001010011000000000001000110000100001010000001000 Ool 01001001010011000000000001000110000100001010000001000 Osul 01001001010011000000000001000110000100001010000001000 Osu2 01001001010011000000000001000110000100001010000001000 Oja 01001001010011000000000001000110000100001010000001000 Ounl 01001001010101000000000001000110000100001010000001000 Oun2 01001001010011000000000001000110000100001010000001000 Eli 01001001010010000010000000101010000100000110000000001 Lfr 10010010010010000010000000101010000010000110000001000 Loc 01001001010010000010000000101010000100000110000001000 Loh 10001010010010000001000000101010000010000110000001000 Lam 10001010010010000001000000101010000010000110000001000 Pall 01000101010100000001000000101010000100000100100000001 Pal2 01000101010100000001000000101010000100000100100000001 Ppu 01000101010010000001000000101010000100000100100000001 Lre 01001001010011000000000001000110000100001010001000000 Vel 01001001010011000000000001000110000100001010001000000 Vtr 01001001010011000000000001000110000100100010001000000 Vpu 010010010-----1000000000001000110000100100010001000000 322 Table 6. Continued Taxa l->2->3->4 >5 >6------>7>8->9--- >10>11->12->13-----> ______abcabcabcabababcdefqhiiklababcabcdeabcabcdabcdabcdefg Vvll 01001001010010001000000001000110000100001010001000000 Vvl2 01001001010010001000000001000110000100001010001000000 W i l 01001001010010001000000001000110000100001010001000000 Vvi2 01001001010010001000000001000110000100001010001000000 Vvi3 01001001010010001000000001000110000100001010001000000 Virl 01001001010010001000000001000110000100001010000001000 Vir2 01001001010010001000000001000110000100001010000001000 Vir3 01001001010010001000000001000110000100001010000001000 Ltel 01001001010100001000000001000110000100001010001000000 Lte2 01001001010010001000000001000110000100001010001000000 Lte3 01001001010100001000000001000110000100001010001000000 Lanl 01001001010010001000000001000110000100001010001000000 Lan2 01001001010100001000000001000110000100001010001000000 Lrd 01001001010100001000000001000110000100001010001000000 Llul 01001001010010001000000001000110000100001010001000000 Llu2 01001001010010001000000001000110000100001010001000000 Llu3 01001001010010001000000001000110000100001010001000000 Llu4 01001001010010001000000001000110000100001010001000000 Lcll 01001001010010001000000001000110000100001010001000000 Lcl2 01001001010010001000000001000110000100001010001000000 Lcl3 01001001010100001000000001000110000100001010001000000 Lra 01001001010100001000000001000110000100001010001000000 Labi 010010010----- 0001000000001000110000100001010001000000 Lab2 01001001010100001000000001000110000100001010001000000 Lhi 01001001010010001000000001000110000100001010001000000 Lon 01001001010010001000000001000110000100001010001000000 Lsal 01001001010010001000000001000110000100001010001000000 Lsa2 01001001010010001000000001000110000100001010001000000 Lov 01001001010010001000000001000110000100001010001000000 Lvel 01001001010010001000000001000110000100001010001000000 Lve2 01001001010010001000000001000110000100001010001000000 Lve3 01001001010010001000000001000110000100001010001000000 Lve4 01001001010010001000000001000110000100001010001000000 Lve5 01001001010100001000000001000110000100001010001000000 Lve6 01001001010010001000000001000110000100001010001000000 Lve7 01001001010010001000000001000110000100001010001000000 Lbrl 01001001010010001000000001000110000100001010001000000 Lbr2 01001001010100001000000001000110000100001010001000000 Lbr3 01001001010100001000000001000110000100001010001000000 Lbr4 01001001010010001000000001000110000100001010001000000 Lcrl 010010010100100010000000C1000110000100001010001000000 Lcr2 01001001010010001000000001000110000100001010001000000 Lcr3 010010010----- 0001000000001000110000100001010001000000 Lea 010010010----- 0001000000001000110000100001010001000000 Lfal 01001001010010001000000001000110000100001010001000000 Lfa2 010010010----- 0001000000001000110000100001010001000000 323 Table 6. Continued Taxa 1->2->3->4 >5>6------>7>8->9---> 10>11->12->13----> ______abcabcabcabababcdefghii klababcabcdeabcabcdabcdabcdefq Lfa3 010010010----- 0001000000001000110000100001010001000000 Lai 01001001010010001000000001000110000100001010001000000 Lpe 010010010----- 0001000000001000110000100001010001000000 Etr 01001001010100100000000001010010000100010000100001000 Ebr 01001001010100100000000001010010000100010000100001000 Eca 01001001010010100000000001010010000100010000100001000 Eral 01001001010010100000000001010010000100010000100001000 Era2 01001001010010100000000001010010000100010000100001000 Character states la through 13g are found in Table 2. The taxa abbreviations are the same as in Table 5 (Appendix C), p. 315-318. LIST OF REFERENCES Arey, L.B. 1921. An experimental study on glochidia and the factors underlying encystment. J.Exp.Zool., 33:463-499. Arey, L.B. 1923. Observations on an acquired immunity to a metazoan parasite. J.Exp.Zool., 38:377-381. Arey, L.B. 1924. 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