(Aspidocotylea) with Comments on Postlarval Development

Proc. Helminthol. Soc. Wash. 55(1), 1988, pp. 62-67

Revision of the Multicalycidae (Aspidocotylea) with Comments on Postlarval Development

D. A. THONEY AND E. M. BURRESON Virginia Institute of Marine Science, School of Marine Science, College of William and Mary, Gloucester Point, Virginia 23062

ABSTRACT: Based upon examination of a large number of specimens from both the Pacific and Atlantic oceans, Taeniocotyle Stunkard, 1962, and Trigonostoma Szidat, 1966, are considered junior synonyms of Multicalyx Faust and Tang, 1936. Trigonostoma callorhynchi Szidat, 1966, is considered a synonym of Multicalyx elegans (Olsson, 1869). The family Multicalycidae consists of a single genus, Multicalyx, and 2 species, M. elegans from holocephalans, and M. cristata from elasmobranchs. Multicalyx elegans matures at a much smaller size than M. cristata. KEY WORDS: Multicalyx, Taeniocotyle, Trigonostoma, Platyhelminthes, Multicalycidae, Aspidocotylea, taxonomy, gall bladder, elasmobranch, holocephalan, postlarval development, synonyms.

The study of aspidogastrids in the gall bladder probably belonged to the same genus, and Gib- of chondrichthian fishes has a long, confused son and Chinabut (1984) based a new family on history (Brinkmann, 1957; Stunkard, 1962; Bray, Multicalyx because the validity of Taeniocotyle 1984) that has resulted in the establishment of and Trigonostoma was open to question. 3 monotypic genera. Olsson (1869) established Our review of the literature in conjunction with the genus Macraspis for M. elegans, a gall blad- our previous studies (Thoney and Burreson, 1986, der parasite of the holocephalan Chimaera mon- 1987) indicated that an examination of a large strosa from the North Sea. Faust and Tang (1936) number of specimens was needed to determine described Stichocotyle cristata from a single spec- if the 3 existing genera, Multicalyx, Taeniocotyle, imen collected from the spiral valve of the cow- and Trigonostoma, were valid. Consequently, a nose ray, Rhinopterus bonasus, in Biloxi Bay, careful review of pertinent literature, and an ex- Mississippi. In order to accommodate their new amination of available deposited specimens and species into Stichocotyle Cunningham, 1884, recently collected material was conducted. The Faust and Tang (1936) emended the generic de- review clearly established the need for a revision scription and subdivided the genus into 2 sub- of the family Multicalycidae. genera; Stichocotyle, to include S. (Stichocotyle) nephropis Cunningham, 1884, and Multicalyx, Materials and Methods to include S. (Multicalyx) cristata Faust and Tang, Most of the individuals examined were stained and 1936. Manter (1954) transferred S. cristata to mounted museum specimens, but some specimens of Macraspis Olsson, 1869. Stunkard (1962), noting M. cristata from our collections were studied in tem- porary glycerin mounts. In all, 47 mature specimens, that Macraspis Olsson, 1869, was preoccupied 16 immature specimens, and the relevant literature by Macraspis MacLeay, 1819, proposed the new form the basis of this revision. Important morpholog- genus Taeniocotyle to replace Macraspis, and el- ical characters were photographed and measurements evated Multicalyx to generic rank for M. cristata, were made with the aid of an ocular micrometer. Spec- which he considered genetically different. Szidat imens examined are listed below. (1966) established a new genus and species, Tri- Multicalyx cristata gonostoma callorhynchi, for worms from Cal- Two mature specimens (1981.11.23.40-45, lorhynchus callorhynchus collected off Argentina. 1981.11.23.46-48) from the British Museum (Natural He separated his new genus from Taeniocotyle History) deposited by R. van der Elst and G. J. B. Ross, respectively; 2 mature (USNM 74467) and 2 immature elegans (although Szidat did not reference Stun- specimens (USNM 74468, 74469) in the U.S. National kard [1962] and called it Macraspis elegans) based Museum Helminth Collection deposited by S. S. Hen- on the presence of a triangular cephalic shield at drix; 2 immature specimens (USNM 51694) deposited the anterior end of the worms. The validity of by H. W. Manter; 1 immature specimen (HWML 22977) in the Harold W. Manter Laboratory, Univer- some of the existing genera has been questioned sity of Nebraska State Museum deposited by H. W. in subsequent papers. Hendrix and Overstreet Manter; 3 mature specimens (USNM 79412, 79413) (1977) stated that T. elegans and M. cristata deposited by D. A. Thoney; 13 mature specimens from 62

Table 1. Meristics and morphometrics of Multicalyx elegans (mean with range in parentheses, in millimeters).

Collection BM (NH)* MACN HWML, USNM USNM ZMUB

Location NE Atlantic SW Atlantic SW Pacific NE Pacific NE Atlantic Host Chimaera Callorhynchus Callorhynchus Hydrolagus colliei Chimaera monstrosa callorhynchus rnilii monstrosa Site Gall bladder Gall bladder Gall bladder Gall bladder Gall bladder No. examined 1 4 8 6 17 Alveoli anterior 17 12(10-14) 13(12-13) 18(15-22) 14(13-18) to ovary Alveoli anterior 91 15(11-26) 40(31-54) 84 (77-96) 41 (11-77) to testis Total alveoli 99 21 (11-37) 55 (27-75) 101(89-113) 49(11-100) Total length 15.1 3.6 (2.3-6.5) 11.7(5.3-15.5) 18.3(14.8-21.3) 9.0 (2.5-22.6) % length anter- 21 52 (46-58) 47 (32-63) 32 (23-37) 48(24-81) ior to ovary % length anter- 94 78(71-85) 81 (65-92) 89 (80-92) 85 (72-90) ior to testis Testis L x W 0.70 x 0.62 0.39(0.14-0.72) x 0.80(0.31-1.40) x 0.76(0.40-1.25) x 0.64(0.08-1.28) x 0.25(0.14-0.40) 0.54(0.18-0.95) 0.58(0.40-1.00) 0.56(0.10-1.35) Ovary L x W 0.55 x 0.39 0.30 x 0.15 0.40(0.17-0.63) x 0.61 (0.20-0.80) x 0.32(0.10-0.67) x 0.45(0.15-0.90) 0.40(0.15-0.60) 0.23 (0.08-0.50) Egg length 0.12(0.11-0.13) 0.14(0.13-0.16) 0.12(0.10-0.15) 0.12(0.09-0.14) 0.12(0.10-0.13) Author Szidat, 1966 Manter, 1954 Henrix and Brinkmann, 1957 Overstreet, 1977

* BM (NH) = British Museum (Natural History), MACN = Museo Argentine de Ciencias Naturales, HWML = H. W. Manter Laboratory, USNM = U.S. National Museum, ZMUB = Zoological Museum, University of Bergen. our own collection; and 2 mature specimens (35 mm slides) loaned by R. A. Campbell, Southeastern Mas- Family Multicalycidae sachusetts University. Gibson and Chinabut, 1984 Taeniocotyle elegans Multicalyx Faust and Tang, 1936 One mature specimen (1976.4.8.155-156) from the =Macraspis Olsson, 1869; Taeniocotyle Stun- British Museum (Natural History), deposited by G. kard, 1962; Trigonostoma Szidat, 1966. Rees; 6 mature specimens (USNM 70861, 70862, 70863) in the U.S. National Museum Helminth Col- DIAGNOSIS: Body greatly elongated, cylindri- lection, deposited by J. E. Lynch; 1 mature specimen cal. Ventral haptor extending nearly entire length (USNM 49154) deposited by H. W. Manter; 1 im- of body, consisting of a well denned single, con- mature and 6 mature specimens (HWML 22978) in the Harold W. Manter Laboratory, University of Ne- tinuous row of alveoli, subdivided by transverse braska State Museum, deposited by H. Manter; and 7 septa. Marginal organs present laterally on each immature and 10 mature specimens (43700, 43701, transverse septum. Mouth terminal, funnel- 43702, 43703, 43704, 43708, 44230) in the Zoological shaped; pharynx muscular; intestine simple, ter- Museum, University of Bergen, Norway, deposited by A. Brinkmann, Jr. minating blindly at posterior end. Testis single, situated at posterior extremity of uterus. Vas def- Trigonostoma callorhynchi erens extending anteriorly ventral or lateral to One mature and 3 immature specimens (27.949b, intestine, forming seminal vesicle distally. Cirrus 27.950) in the Museo Argentino de Ciencias Naturales pouch claviform, enclosing seminal vesicle, "Bernardino Rivadavia" e Institute Nacional de In- vestigacion de las Ciencias Naturales, deposited by L. prostate complex, and ejaculatory duct; protru- Szidat. sible cirrus thick walled, muscular. Genital pore ventral, anterior to haptor. Ovary anterior to tes- Results tis; uterus descending from ovary posteriorly to A revision of the family Multicalycidae is pre- level of testis, then turning and ascending ante- sented below. Comparative meristics and mor- riorly to genital pore. Eggs operculate, oval in phometrics of M. elegans from various parts of shape, usually filling uterus in mature specimens. its geographic range are listed in Table 1. Vitellaria consisting of 2 laterally situated bands

Copyright © 2011, The Helminthological Society of Washington 64 PROCEEDINGS OF THE HELMINTHOLOGICAL SOCIETY of follicles extending from near posterior end posterior end of body. This pattern can be seen anteriorly to level between ovary and genital pore. by examination of Table 1 and Figures 6-8. Two lateral excretory ducts descending poste- Number of alveoli anterior to testis is greater in riorly from level of pharynx to end of vitellaria larger, and presumably older, individuals. Spec- where ducts fuse to form excretory vesicle and imens from Hydrolagus collet, which were all exit through dorso-terminal pore. Parasitic, usu- mature, have many more alveoli anterior to testis ally in gall bladder of Chondrichthyes. than those from Callorhynchus callorhynchus, TYPE SPECIES: Multicalyx cristata Faust and which were mostly juveniles. The same trend is Tang, 1936. seen in percentage of length anterior to ovary, where higher percentages are found in juvenile Multicalyx cristata Faust and Tang, 1936 worms. Worms become mature during the time (Figs. 1-3) required for development of 27 to 37 alveoli. =Stichocotyle (Multicalyx) cristata Faust and Tang, 1936; Macraspis cristata (Faust and Discussion Tang, 1936) Manter, 1954; Macraspis sp. of Taxonomy Manter (1954); Multicalyx multicristata Pa- Our examination of the specimens of Multi- rukhin and Tkachuk, 1980. calyx cristata, Taeniocotyle elegans, and Trigo- DIAGNOSIS: Testis elongate, not located at nostoma callorhynchi indicates that there is in- posterior end of worm except in young individ- sufficient morphological difference to warrant uals. Ovary located posterior to 60th alveolus in separate genera. Differences in position of testis mature individuals. Marginal organs only slight- and ovary, number of alveoli, and shape of testis, ly protrusible. Testis and ovary not apparent at pharynx, and marginal organs are considered by 16-alveoli stage of development. Pharynx round. us to be specific characters only. Multicalyx Faust Mature individuals may reach 60 cm in length and Tang, 1936, is the oldest valid nominal genus with over 1,500 alveoli. Parasites of gall bladder and has priority; Taeniocotyle Stunkard, 1962, of elasmobranchs; immature individuals found and Trigonostoma Szidat, 1966, are regarded as in littoral teleosts. junior synonyms. Szidat (1966) established a new genus and Multicalyx elegans (Olsson, 1869) comb. n. species for his specimens based primarily on the (Figs. 4-10) triangular shape of the buccal funnel (Fig. 9). After examination of Szidat's specimens and of =Macraspis elegans Olsson, 1869; Taeniocotyle many specimens ofM elegans (Table 1), we have elegans (Olsson, 1869) Stunkard, 1962; Tri- concluded that the shape of the buccal funnel gonostoma callorhynchi Szidat, 1966. varies among specimens and probably depends DIAGNOSIS: Testis round to slightly oval, lo- on its state of contraction at the moment of fix- cated near posterior end of body. Ovary located ation. A triangular buccal funnel was also ob- anterior to 25th alveolus. Testis and ovary ap- served in specimens of M. elegans collected from parent when 11 alveoli have developed. Margin- C. milii from the southwest Pacific (Fig. 10) and al organs highly protrusible. Pharynx elongate. several other characters listed in Table 1 also Mature individuals reach 23 mm in length with overlap between these species. In addition, reex- as many as 113 alveoli. Parasites in gall bladder amination of Szidat's specimens revealed that of holocephalans. the eggs are operculate, as in M. elegans. Also, POSTLARVAL DEVELOPMENT: Testis and ovary Szidat identified a juvenile specimen of M. ele- visible in specimen with 11 alveoli; gonads small, gans in the same host as T. callorhynchi, indi- positioned adjacent to each other at posterior end cating that there is no host specificity or geo- of worm (Fig. 6). Gonads have increased in size graphical boundary between M. elegans and T. when 14 alveoli have developed (Fig. 7), and by callorhynchi. For these reasons, we consider T. 25 alveoli gonads have grown apart by apposi- callorhynchi a junior synonym of M. elegans. tion and subsequent elongation of body (Fig. 8). Multicalyx elegans has been collected from the Alveoli develop at posterior end of body and Pacific and Atlantic oceans in both the Northern migrate anteriorly between ovary and testis as and Southern hemispheres. body elongates. Ovary remains at approximately As indicated in the diagnoses, several signifi- level of 10th to 22nd alveolus, testis remains at cant characters separate M. cristata and M. ele-

Figures 1-8. Morphology of the genus Multicalyx. 1. Midbody view of M. cristata showing testis (T) and uterus (U), bar = 0.5 mm. 2. Marginal organs (arrows) of M. cristata, bar = 0.15 mm. 3. Juvenile M. cristata with 12 alveoli, bar = 0.5 mm. 4. Posterior end of M. elegans showing testis (T) and uterus (U), bar = 0.5 mm. 5. Marginal organs (arrows) of M. elegans, bar = 0.25 mm. 6. Juvenile M. elegans with 11 alveoli showing developing testis (large arrow) and ovary (small arrow), bar = 0.5 mm. 7. Juvenile M. elegans with 20 alveoli, arrows as in Figure 6, bar = 0.5 mm. 8. Juvenile M. elegans with 26 alveoli, arrows as in Figure 6, bar = 0.5 mm.

only a few alveoli ever occurred posterior to the testis (Fig. 4). Specimens collected from littoral teleosts are thought to be immature M. cristata because: (1) their alveoli resemble the anterior alveoli of adult specimens (Thoney and Burreson, 1987), (2) they occur in fishes that are prey of elasmobranchs (Thoney and Burreson, 1986), (3) they lack protrusible marginal organs, and (4) their gonads are not as well developed as those of juvenile M. elegans (Fig. 3, cf. 6). The position of the ovary posterior to the 60th alveolus in adult M. cristata suggests that development of gonads in M. cristata may occur at a later stage than in M. elegans. Unfortunately, immature individuals of M. cristata have not been collected from elasmobranchs so it is difficult to identify the specimens from teleosts with certainty. They are clearly not M. elegans, but they may represent an undescribed species.

Acknowledgments We wish to thank the following individuals for loan of specimens: R. A. Bray, British Museum Figures 9, 10. Morphology of the anterior end of (Natural History); M. H. Pritchard, University M. elegans. 9. Specimen collected by L. Szidat from of Nebraska State Museum; E. Willassen, Uni- Callorhynchus callorhynchus that he called Trigono- stoma callorhynchi, p = pharynx, arrow = cirrus, versity of Bergen; J. R. Lichtenfels, U.S. National bar = 0.025 mm. 10. Specimen of M. elegans collected Museum Helminth Collection; T. Stadler, Mu- by H. Manter from C. milii showing obvious triangular seo Argentine de Ciencias Naturales; and R. A. cephalic shield, p = pharynx, bar = 0.25 mm. Campbell, Southeastern Massachusetts Univer- sity. G. W. Benz, University of British Columbia provided a copy of Szidat (1966) translated by gans. Other characters, such as egg size, overlap W. L. Marcus. W. J. Hargis, Jr., made helpful greatly (Thoney and Burreson, 1987). The host comments on the manuscript. VIMS Contribu- specificity of M. cristata in elasmobranchs and tion No. 1398. M. elegans in holocephalans suggests that these 2 species may have diverged at an early period Literature Cited of chondrichthyan evolution. Bray, R. A. 1984. Some helminth parasites of marine fishes and cephalopo'ds of South Africa: Aspido- Postlarval development gastrea and the digenean families Bucephalidae, The pattern of development of M. elegans is Haplosplanchnidae, Mesometridae and Fellodis- tomidae. Journal of Natural History 18:271-292. very similar to that suggested for immature M. Brinkmann, A., Jr. 1957. Fish trematodes from Nor- cristata by Thoney and Burreson (1987), where wegian waters. Ha. The Norwegian species of the alveoli produced at the posterior end of the body orders Aspidogastrea and Digenea (Gasterosto- continue development anterior to the testis until mata). Universitetet i Bergen, Arbok 1957, Na- some period near maturity. Subsequently, alveo- turvitenskapelig Rekke 4:1-31. Faust, E. C., and C.-C. Tang. 1936. Notes on new li develop posterior to the testis as the body elon- aspidogastrid species, with a consideration of the gates and this development causes the testis to phylogeny of the group. Parasitology 28:487-501. be positioned relatively more anteriorly in the Gibson, D. L, and S. Chinabut. 1984. Rohdella si- body until there may be only 28% of the body amensis gen. et sp. nov. (Aspidogastridae: Roh- dellinae subfam. nov.) from freshwater fishes in anterior to the testis in M. cristata, compared Thailand, with a reorganization of the classifica- with greater than 65%, usually 80%, in M. ele- tion of the subclass Aspidogastrea. Parasitology gans. In the specimens of M. elegans examined, 88:383-393.

Hendrix, S. S., and R. M. Overstreet. 1977. Marine nales biliares de Callorhynchus callorhynchus L. aspidogastrids (Trematoda) from fishes in the del Atlantico sur. Neotropica 12:67-71. northern Gulf of Mexico. Journal of Parasitology Thoney, D. A., and E. M. Burreson. 1986. Ecological 63:810-817. aspects of Multicalyx cristata (Aspidocotylea) in- Manter, H. W. 1954. Some digenetic trematodes from fections in Northwest Atlantic elasmobranchs. fishes of New Zealand. Transactions of the Royal Proceedings of the Helminthological Society of Society of New Zealand 82:475-568. Washington 53:162-165. Olsson, P. 1869. Nova genera parasitantia Copepo- , and . 1987. Morphology and devel- dorum et Platyelminthium. Lunds Universitets opment of the adult and cotylocidium of Multi- Arsskrift6:l-6. calyx cristata (Aspidocotylea), a gall bladder par- Stunkard, H. W. 1962. Taeniocotyle nom. nov. for asite of elasmobranchs. Proceedings of the Macraspis Olsson, 1869, preoccupied, and sys- Helminthological Society of Washington 54:96- tematic position of the Aspidobothrea. Biological 104. Bulletin 122:137-148. Szidat, L. 1966. Trigonostoma callorhynchi n. g., n. sr> Trematoda subclase Aspidogastrea) de los ca-