SRQ-NERp·3

The Freshwater Bivalve Mollusca (Unionidae, Sphaeriidae, Corbiculidae) of the Savannah River Plant, South Carolina

by Joseph C. Britton and Samuel L. H. Fuller

A Publication of the Savannah River Plant National Environmental Research Park Program United States Department of Energy ...------NOTICE ------,

This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the United States Depart­ mentof Energy.nor any of theircontractors, subcontractors,or theiremploy­ ees, makes any warranty. express or implied or assumes any legalliabilityor responsibilityfor the accuracy, completenessor usefulnessofanyinformation, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights.

A PUBLICATION OF DOE'S SAVANNAH RIVER PLANT NATIONAL ENVIRONMENT RESEARCH PARK

Copies may be obtained from NOVEMBER 1980 Savannah River Ecology Laboratory SRO-NERP-3

THE FRESHWATER BIVALVE MOLLUSCA (UNIONIDAE, SPHAERIIDAE, CORBICULIDAEj OF THE SAVANNAH RIVER PLANT, SOUTH CAROLINA

by JOSEPH C. BRITTON Department of Biology Texas Christian University Fort Worth, Texas 76129 and SAMUEL L. H. FULLER Academy of Natural Sciences at Philadelphia Philadelphia, Pennsylvania

Prepared Under the Auspices of The Savannah River Ecology Laboratory and Edited by Michael H. Smith and I. Lehr Brisbin, Jr.

1979

TABLE OF CONTENTS Page INTRODUCTION 1 STUDY AREA " 1 LIST OF BIVALVE MOLLUSKS AT THE SAVANNAH RIVER PLANT...... 1 ECOLOGICAL CONSIDERATIONS " 2 COLLECTING TECHNIQUES 3 PRESERVATION OF BIVALVE MOLLUSKS FOR IDENTIFiCATION...... 4 KEY TO SPECIES OF BIVALVE MOLLUSKS OF THE SAVANNAH RIVER PLANT...... 5 TAXONOMIC CRITERIA " 7 DESCRIPTIONS OF THE BiVALViA...... 7 Family Unionidae 7 Subfamily Unioninae 7 Genus Elliptio " 7 Elliptio complanata " 7 Elliptio icterina " 9 Elliptio lanceo/ala 10 Elliptio congaraea " 11 Elliplio Iratema 12 Genus Uniomerus 12 Uniomerus tetralasmus 13 Subfamily Anodontinae 13 Genus A/asmidonla " 13 A/asmidonta triangu/ata " 13 Genus Anodonta 14 Anodonta imbecillis 14 Anodonta couperiana 15 Anodonta cataracla 15 Genus Slrophitus ...... 15 Strophitus undu/atus 16 Subfamily Lampsilinae " 16 Genus Carunculina " 16 Carunculina pulla 16 Genus Villosa " 16 Villosa aeiumbts 16 Villosa vibex 17 Genus Lampsilis 17 Lampsilis cariosa 17 Lampsilis radiata sp/endida 18 Family Corbiculidae 19 Genus Corbicula 19 Corbicu/a fluminea ,...... 19 Family Sphaeriidae 20 ACKNOWLEDGMENTS 21 LITERATURE CiTED 22 GLOSSARY 24 ILLUSTRATIONS 26 PLATE I 28 PLATE II 30 MAP LEGENDS 32

INTRODUCTION laboratory where research can be conducted in both undisturbed and stressed ecosystems. This is the third in a series of guides to the fauna of During May, June, and July 1977, one of us (JCB) the National Environmental Research Park of the spent several weeks surveying the various aquatic Savannah River Plant. As with the former work, on the habitats on or near the SRP for bivalve mollusks. A total decapod crustaceans (Hobbs et al., 1976), the main of 46 specific localities was visited, of which 26 proved purpose of the present paper is to aid investigators with to have at least one species of bivalve. Additional the identification of a taxonomic group which is often material was provided (by SLHP) from extensive difficult for inexperienced investigators to identify - in collections made during numerous stream surveys for this case, the bivalve mollusks that can be expected to the Academy of Natural Sciences at Philadelphia be found at the Savannah River Plant (SRP). (ANSP). Within the last ten years, two important studies have been made of the unionid mussels of the southern Atlantic slope drainage. The first (Johnson, 1970) is LIST OF BIVALVE MOLLUSKS AT THE SRP monographic in scope and is an indispensible guide to the unionid shells from southern Georgia to Virginia and There are several suprageneric classifications of the Maryland. The second paper (Fuller, 1971) is more Unionacea, including those by Ortmann (1910, 1911, restricted in scope, dealing primarily with mussels of the 1912, 1916, and 1919), Frierson (1927), Modell (1942, Savannah River system, but is important because of the 1949, 1964), Haas (l969a, 1969b) and Heard and Guckert emphasis upon the soft-part morphology of bivalves. The (1971). Following the similar treatments by Johnson present paper is in no way intended to supplant either of (1970) and Fuller (1971), we employ the Ortmann system these important studies. The reader is encouraged to here. Three families, 14 genera, and 26 species are have both papers readily available before any extensive recognized with geographic ranges which include or are research on the Bivalvia of this region is attempted. You near the SRP. They are included in the following list. will find here, however, a handy guide and reference to Twenty-three of these species were collected during the the more common and abundant bivalves in the waters summer of 1977 andlor during ANSPISRP surveillance of the SRP. A dichotomous taxonomic key is provided since 1955. The remaining three species may occur to common forms and to unreported species whose within the boundary of the SRP andlor in the adjacent geographic distributions include nearby localities. Every portions of the Savannah River. They are indicated by species collected during field reconnaissance in the an asterisk in the list below and are included in the key. summer of 1977 is described, and a discussion of some Otherwise, these three species are not given additional aspects of its ecology, life history, larval hosts, and treatment herein. other pertinent information is provided. SUPERFAMILY UNIONACEA Thiele 1934 FAMILY UNIONIDAE Fleming 1828 SUBFAMILY UNIONINAE Swainson 1840 STUDY AREA GENUS Fusconaia Ortmann 1912 The Savannah River Plant (SRP) occupies "Fusconaia masoni (Conrad approximately 200,000 acres in southern South Carolina, 1834)' occupying portions of Aiken, Barnwell and Allendale GENUS Uniomerus Conrad 1853 counties, near the cities of Augusta, Georgia, and Aiken, Uniomerus tetralasmus (Say South Carolina. The SRP is located just below the Fall 1831) Line in the Atlantic Slope Coastal Plain. Five minor GENUS Elliptio Rafinesque 1819 drainage systems flow from or through the SRP to the Elliptio congaraea (Lea 1831) Savannah River, which courses for 22 miles along the E. complanata (Lightfoot 1786) southwestern border of the plant. A variety of terrestrial E. fraterna (Lea, 1852) and aquatic habitats occur within the SRP boundaries. E. lanceolata (Lea 1828) The former include lowland hardwood forests and E. icterina (Conrad, 1834) cypress-gum swamps, turkey oak and longleaf pine SUBFAMILY ANODONTINAE Swainson sandhills, upland oak-hickory forests, and large old-field 1840 areas. The aquatic habitats include the Savannah River GENUS Lasmigona Rafinesque 1831 and adjacent swamplands, several reservoirs including *Lasmigona (Platynaias) the 2,800-acre nuclear reactor cooling reservoir, Par subviridis (Conrad 1835) Pond, various natural and thermally affected (by several GENUS Alasmidonta Say 1818 nuclear production reactors) streams, and a number of Alasmidonta (Alasmidonta) Carolina bays, beaver-dam ponds, and abandoned farm triangulata (Lea 1858) ponds. Designated as the first National Environmental *A. (Decurambis) varicosa Research Park, the SRP is a unique protected outdoor (Lamarck 1819)

~~~~--~- --_.----_.. GENUS Anodonta (Lamarck 1799) are often very abundant in substrates of shallow pools Anodonta (Utterbackia) and protected coves or among reeds where various fish couperiana Lea 1840 species may seek shelter. A. (U.) imbecillis Say 1829 There are some conditions where few if any clams or A. (Pyganodon) cataracta Say mussels should be expected. Ephemeral ponds or 1817 streams rarely harbor bivalves. Even the largest Carolina GENUS Strophitus Rafinesque 1820 bays, which are never completely dry, may be devoid of Strophitus undulatus (Say 1817) clams. Permanent waters with poor circulation or flow SUBFAMILY LAMPSILINAE von Ihering rarely produce large clam populations. An abundance of 1901 individuals of certain species (e.g., Anodonta imbecillisi GENUS Carunculina Baker 1898 may occur in Par Pond and other reservoirs at SRP but Carunculina pulla (Conrad 1838) we have never found more than four or five bivalve GENUS Vil/osa Frierson 1927 species in these lakes. As sessile filter-feeders, most Vil/osa vibex (Conrad 1834) freshwater bivalves fare best when nutrient-laden waters V. delumbis (Conrad 1834) flow continuously over them. GENUS Lampsilis Rafinesque 1820 SRP streams are not especially rich in suspended Lampsilis radiata splendida (Lea particulate nutrients (Langley and Marter, 1973), hence 1838) the populations of bivalves in these waters are limited. L. cariosa (Say 1817) Clean sand bars in the fast-flowing streams may harbor a SUPERFAMILY CORBICULACEA Gray 1847 few specimens, but most bivalves of SRP streams occur FAMILY CORBICULIDAE Gray 1847 along banks or in stream eddies where nutrients tend to GENUS Corbicula von Muhlfeld 1811 accumulate. The Sphaeriidae or fingernail clams are an Corbicula (Corbicula) fiuminea exception. They can be found in the same localities as (Miiller 1774) the stream Unionidae, but they are also particularly FAMILY PISIDIIDAE Gray 1857 abundant in gravel substrates of stream riffies. GENUS Pisidium Pfeiffer 1821 The river environment provides a greater nutrient load Pisidium americum (Muller 1774) than that of smaller streams; as might be expected, the Pisidium casertanum (Poli 1791) variety of bivalve populations is greater there. If one Pisidium compressum Prime 1851 wishes to collect the rarer species of mussels in the Pisidium dubium (Say 1834) vicinity of the SRP, localities in or near the Savannah GENUS Musculium River should be searched first. Mussels and clams are Musculium transversum (Say most abundant on semi-protected shoals or bars of the 1829) river where there is both adequate flow and protection GENUS Eupera Bourguignat 1854 against the catastrophic effects of flooding. They also Eupera cubensis (Prime 1865) occur in deeper parts of the river, but collecting in these areas is considerably more difficult. The recent introduction of Corbicula fiuminea into the "This is Pleurobema mason; teste Johnson (1970). See Fuller (1973) for Savannah River (or any waterway in this country) raises extensive discussion. some concern about the effects that this expanding population may have on native bivalves. C. fluminea can reach exceptionally high densities just a few years after being introduced into an area (see below), Eventually. shell densities may become so great as to reduce the ECOLOGICAL CONSIDERATIONS habitable space for other clams (e.g., Eng, 1977). Freshwater bivalve mollusks, especially the unionids , Alternately, nutrient and/or chemical resources may be tend to be most abundant in flowing streams and rivers. depleted or otherwise made unavailable to native The numbers of individuals and the species diversity species. The impact of C. fluminea on other clams is yet usually diminish in the still waters of lakes or basins to be assessed, but one should be aware that a possible (e.g., Carolina Bays). Regardless of habitat, the change in population densities may occur as a result of distribution of bivalves is often patchy, clumped, or this invading bivalve. otherwise irregular. Large numbers of clams may be In addition to nutrients, there are other aspects of collected in one area, whereas in a similar environment water chemistry that may also influence the distribution only a few meters away, few or no specimens may be of bivalves. Surface waters of southern South Carolina found. The irregular distribution of unionids may be typically are slightly acidic and have low conductivity. related to the distribution patterns of freshwater fish Of the several ionic components which influence which are employed by larval clams (glochidia) as hosts conductivity, calcium is one of the most important to for dispersal (see later discussion). Freshwater mussels mollusks. Calcium is required by bivalves for shell 2 formation. If it is in limited supply, the growth and/or eliminate considerable quantities of pseudofecal abundance of bivalve species may be similarly limited. material). Additional details of the mechanics and This becomes especially critical in slightly acidic waters. phsysiology of the filter-feeding process can be found If calcium carbonate shells are exposed directly to elsewhere (e.g., Owen, 1966). acidity, they will undergo dissolution. Mollusks which The similarities of habitat, feeding behavior, and live in acidic waters usually develop thick, organic numerous other traits are presumably responsible for a periostracallayers to protect the underlying, inorganic high degree of convergent evolution with respect to shell carbonate from chemical breakdown-but mechanical morphology within the Unionacea, Sphaeriidae, and abrasion can wear away the protective periostracum, Corbiculacea. There are numerous examples among the thereby exposing the calcium carbonate shell to chemical Unionacea of distinctly different soft-parts enclosed dissolution. Thus, there is a series of interactions that within superficially similar shells. Such is the case with ensure a turnover of calcium within the aquatic system. many of the SRP unionaceans. At first glance, the shells In flowing waters, the net effect will be a loss of calcium of several SRP mussel species will appear almost to the system if there are no local sites of replenishment. identical. This makes the task of identification especially In the vicinity of the SRP, several aquifers flow from difficult for those working with the group for the first calcium-rich groundwater sources to the surface and time. Johnson (1970) presented an extensive discussion provide constant replenishment (Langley and Marter, of zoogeographical and phylogenetic relationships among 1973). Thus, although the calcium content of surface Atlantic slope drainage unionids. waters at the SRP seems low (generally less than 1.5 The life cycle of freshwater bivalves varies according rng/I), this element is in constant supply from to the taxonomic groups. All bivalves at the SRP brood groundwater sources and is supplemented to a small larvae in gill marsupia. The Sphaeriidae and degree by the dissolution of older and/or dead shells. Corbiculidae produce brood chambers within the inner The loss of shell material as a result of dissolution may demibranchs of the gill. The former group restricts be more critical to the individual mollusk. If a clam marsupia to the anterior portions of the demibranch, and cannot replace shell material faster than it is being the latter employs the entire demibranch. Members of removed by mechanical abrasion or by chemical both families release the larvae to the environment, dissolution, eventually the shell will become perforated. where they undergo metamorphosis into juvenile clams. One occasionally finds living specimens with a perforate Heard (1977) discusses in considerable detail the umbo exposing the underlying mantle tissue to the reproductive biology of the Sphaeriidae, and additional external environment. More often, numerous unhinged remarks on the life cycle of Corbicula are presented dead valves with umbonal perforations are found, below. attesting to the frequency with which this process The Unionacea may brood larvae in all four occurs. Although there are no relevant quantitative data, demibranchs (e.g., Amblema, not found in this area), in one wonders how important this process might be in only the outer demibranch (e.g. Elliptio), or in only limiting the bivalve populations and especially individual specific portions of the outer demibranchs (e.g., species in the SRP area. Lamps/lis). Upon release from the brood chamber, the All of the bivalves at the SRP are filter-feeding unionacean larva (glochidium) usually must undergo an organisms. Waterborne food enters the mantle cavity obligatory parasitic encystment on gills or fins of through a posterior branchial aperture and circulates freshwater fishes if development is to proceed. See the among the gill dernibranchs, on whose surfaces "Life History" section of Elliptio camplanata for particulate material is trapped. The water exits additional information on the reproductive behavior and posteriorly through an anal aperture located dorsal to the the larvae of freshwater mussels. branchial aperture. The branchial and anal apertures of Corbicula and some of the Sphaeriidae are siphonal. In COLLECTING TECHNIQUES most bivalves, the branchial aperture is papillate; the papillae are usually employed as a screen or filter for Clams and mussels are most easily collected during very large particles. The anal aperture mayor may not the drier months, when the water levels and flow rates be papillate, and the presence or absence of papillae of streams or rivers are low. Shoals or bars in large here is a useful criterion for identification. rivers become treacherous or deeply submerged during Food material and other particulate matter trapped by high water periods, this makes collecting difficult and cilia of the gills are passed either toward the mouth by even dangerous. In the drier seasons, the shoals often specific ciliary tracts or along rejection paths for become partially exposed, easily worked, and often elimination from the mantle cavity. Rejected material highly productive of mussels and clams. A particularly that does not pass into the digestive tract is eliminated good river locality for mussels is in the lee of a sharp as "pseudofeces" through the branchial aperture and bend, i.e., along the shore opposite the cutting bank. between the mantle margins anterior of the incurrent Mussels in smaller streams (such as the many at the aperture. (Bivalves held in aquaria frequently will SRP) may be found on mid-stream shoals, but more 3 frequently they lie partially buried in sand, mud or must use hands to sift along a sandy spit or among roots gravel along the stream bank. Sandy, sandy gravel, or under a bank. A small rake may be useful in some sandy mud bottoms seem to be the most productive localities but, if there is a large amount of rooted substrates, but some mussels are characteristically found vegetation, it may become frequently tangled and prove in abundance among very fine, organically rich ineffective. sediments trapped at the bases of tree roots or in calm If one is searching for Sphaeriidae or Corbicula, areas of the stream. Rapidly shifting, transitory sand screening or seiving the substrate often is an efficient bars are usually unsuitable habitats, but one species in method of obtaining numerous specimens. Note, the Altamaha River basin of Georgia iCanthyria spinosa however, that screening rarely expedites the search for (Lea)) has spines on each valve, presumably to facilitate most of the larger mussels. Dip nets have been shell anchorage in this kind of habitat. successfully employed at SRP for collecting bivalves, The Sphaeriidae, Corbicula, and some Unionidae and they are especially well suited for obtaining commonly occur in the gravel substrates of stream riffle fingernail clams and Corbicula. These clams almost zones. This is a particularly good locality to search for always lie buried in the substrate, so a dip net should be fingernail clams. raked through the streambed and then washed of its If collecting is done during a period of low water and sediment burden before the net is searched. Look high air temperature, a word of caution is in order. carefully among the organic debris for smaller Specimens collected for laboratory experiments should specimens. then be taken only if they were covered by at least In shallow riffle zones, a Surber sampler or the PIBS several inches of water. Some clams (Corbicula (Portable Invertebrate Box Sampler) device can provide fiumlnea, in particular) may suffer latent mortality reasonably accurate quantitative estimates of the several days or even weeks after air exposure or heat Sphaeriidae and/or Corbicula populations. Like other stress in temperatures above 37°C (Coldiron, 1975). On quantitative samplers, however, these devices are the other hand, if specimens are required for museum generally ineffective for quantitative sampling of collections, locality records, or gross morphological unionids. studies, the more easily obtained exposed or Most of the methods described above can be used semi-exposed individuals are preferred. The exposure along lake shores and in the shoals of larger rivers, as has likely severely weakened many of these specimens, well as in the smaller stream localities of the SRP. For and collecting them instead of reproductive stocks from deeper lake or river waters, a shell dredge (e.g., Wildlife deeper waters will minimize depletion of the healthy Supply Co., No. 175) may be useful. The effectiveness bivalve populations. of dredging is highly dependent upon the nature of the There is no "best method" to collect bivalve substrate. Heavy vegetative cover, such as that mollusks. Many standard quantitative techniques (e.g., frequently occurring on SRP lake bottoms, or the grab samplers) are ineffective with some bivalve groups, numerous snags or stumps that are common in the especially the Unionidae. Grab samplers will almost Savannah River, tend to reduce the effectiveness of the never collect large mussels in proportion to their actual shell dredge as a bivalve collector. Nevertheless, during abundance in a locality. These devices may be useful, June, 1977, good results were obtained by dredging in however, for population estimates of Corbicula or the some parts of Pond B and Par Pond in order to obtain Sphaeriidae. The most reliable techniques for sampling Anodonta imbecillis and along deeper shoals in the bivalves are hand methods, despite numerous attempts Savannah River in order to obtain Corbicula fluminea. by a variety of workers to develop other sampling Specimens have been collected by use of mask, procedures. There are several kinds of hand collecting snorkel, and fins in all localities sampled. The use of techniques, all of which should be attempted at a given mask and snorkel along shoals in the Savannah River locality. was especially productive. Diving with SCUBA gear was First and foremost, the most reliable of all methods to attempted in Par Pond, with only fair results. The low collect larger unionids remains hand-sifting and visibility and heavy plant growth on the bottom inhibited searching the substrate. According to the preference of the diver's collecting effectiveness considerably. the collector, gloves may be worn to minimize abrasions and minor lacerations. One may "scan" a clear stream PRESERVATION OF BIVALVE MOLLUSKS FOR for larger specimens by walking along a bank or in the IDENTIFICATION shallows and looking for the characteristic wedge-shaped posterior region projecting from the substrate in shallow Shell features of bivalve mollusks are often used as water. The collector should always walk upstream, the only criteria for identification. Indeed, it is far easier thereby ensuring that his view will be in clear, and inexpensive to prepare and maintain a collection of undisturbed water. In more turbid streams, or in low dry shells than a "wet collection." Yet many Unionacea flow conditions, the scan technique may be impossible. and Sphaeriidae are difficult or impossible to identify at The collector then must rely upon a blind search and the species level by using shell characters exclusively. 4 Hence, both "wet" and "dry" collections are almost intact from the surrounding shell by careful recommended, especially if the purpose of the collection dissection. If this is done, identification should be is to be for later reference. Techniques for both kinds of maintained between shell and soft parts. A fine wire collections will be described. with an identifying label can be affixed to the muscular Tissue preservation is achieved in 5-6% neutral or foot tissue, and a similar identifying number can be buffered formalin. It is recommended that specimens be written on the interior surfaces of both valves using a "pegged" open to facilitate penetration of the permanent ink. preservative. This can be done by inserting small If one intends to keep only shell material of some wooden wedges between the valves of a naturally gaping specimens, there are easier methods to obtain cleaned clam before it has an opportunity to close. Even with shells. The quickest procedure is to place living pegging, the soft tissues contract strongly upon exposure specimens in boiling water. Within a few minutes, the to the preservative. To avoid this response, clams and valves will gape noticeably. Remove the specimens from mussels can be relaxed in a dilute solution containing the boiling water and lift the soft parts away from the Nembutal" (sodium pentobarbital). shells. Tissues should never be extracted for Place the specimens to be relaxed in a container just preservation using this method, for there is considerable large enough to hold them without expanded soft parts and progressive shrinkage of the soft parts during touching with other specimens, but small enough to boiling. minimize fluid volumes. Add enough natural water to the When freshwater shells are dried, there is usually a container barely to cover the bivalves. Then add ten to problem with cracking, peeling, or warping of twenty drops of Nembutal (stock solution containing 50 periostracal layers. Sometimes this can be retarded by mg sodium pentobarbital per ml fluid carrier) to the lightly coating the valves with mineral oil. Thin shells. water. Do not disturb the specimens for at least one such as those of Anodonta, are also plagued by cracking hour. Then touch the extended foot of a clam with a or fragmentation of carbonate layers when dried. Even probe. If it retracts quickly and/or if no specimens have the application of mineral oil may not prevent this kind exposed soft parts, add to the water a quantity of of damage. Nembutal equal to the first dose. Repeat this process, reducing the quantity of Nembutal you add as the "Abbott Laboratories, North Chicago, Illinois. This barbituate is available only by prescription, and/or federal (FDA) permit for Class I response becomes progressively lethargic. Eventually, proscribal substances. there will be little or no retraction upon tactile stimulation. At this point gradually begin to introduce small amounts of 5-6% formalin or 70% alcohol into the KEY TO THE SPECIES OF BIVALVE MOLLUSKS water. We have found alcohol more effective at this OF THE SAVANNAH RIVER PLANT stage, as it acts as a further relaxing agent, particularly if it is added slowly. Eventually, however, the specimens Two excellent keys to the Unionacea of this region should be transferred to 5-6% formalin solution for have already appeared. Johnson (1970), treating the complete fixation. entire Unionacean fauna of the southern Atlantic slope A word of warning: The relaxation technique region, relied exclusively upon shell morphology in his described above is a very tedious process and not key. Fuller (1971) employed soft-part criteria (especially always successful. Furthermore, it seems to work more the nature of the mantle margin) in his key of the effectively in some genera than in others. Be prepared unionaceans of the Savannah River system. The key for several repetitions, if necessary, before achieving employed in this paper is more restrictive than either of satisfactory results. Fuller (1971) has figured specimens the two previous efforts: only. those species known or of Lampsilis radiata splendida and L. r. siliquoidea reported to occur in the vicinity of the SRP are included. (Lea) that were relaxed by the Nembutal technique and Also, it is organized differently: some species "key out" are fine examples of excellent relaxation and in associations different from those in Johnson's or preservation. Fuller's works. This was done purposely in an attempt Specimens should remain in 5-60/", buffered formalin to enhance the value of all of the keys. Johnson has for one to several weeks to ensure good penetration of excellent plates of comparative shell material and types. the fixative. Eventually, however, they should be which should be consulted. Fuller has numerous transferred to 70% ethanol (ethyl alcohol). Pigmented anatomical notes, which are also valuable aids in areas will rapidly fade in alcohol; so, if notes are to be identification. There are some cases, however, in which made on pigmentation in tissues, this should be done the existing keys simply cannot be improved upon. The shortly after fixation or, better still, in life before reader should not be surprised to find a few couplets preservation. similar or identical in all three works. A glossary is Sometimes it is desirable to separate soft parts from included at the end of this report in order to provide a shell material and to leave the shell dry and the soft ready reference to the more technical terms used in this parts in alcohol. The preserved tissue can be removed key. 5 Some species not reported from the SRP are included 9a Pseudocardinal teeth small, poorly formed, or below. They are indicated by an asterisk. No treatment vestigial; posterior ridge not sharply angular of these species is given in the descriptive section that ...... 10 follows. 9b A single, distinctly elevated pseudocardinal tooth in each valve; posterior ridge sharply an- Ia Posterior portion of mantle fused to form one or gular Alasmidonta triangalata two elongate siphons 2 lOa Pseudocardinal teeth reduced to slight swellings Ib Posterior mantle unfused ventral to position of on hinge plate anterior to umbo; posterior slope anus; incurrent (branchial) and anal areas are usually without radial wrinkles ... .Strophitas unfused but differentiated apertures; mantle undulatus fusion may occur dorsal to position of lOb Pseudocardinal teeth more distinctly formed, anus U nionacea 3 single in each valve; posterior slope with radial 2a Shell oval or trigonal; umbo usually central; wrinkles "Alasmidonta varicosa deeply incised broadly spaced concentric rings Ila Mantle anterior to branchial aperture undiffer­ present over entire surface of valve; three cardi­ entiated and smooth; marsupium formed along nal teeth in each valve (one in each valve is total length of outer demibranchs, inner demi­ closely applied to dorsal surface of hinge branchs mayor may not form marsupium9 shell plate) (Corbiculidae) Corbicula fiuminea lacking conspicuous sexual dimorphism ....12 2b Shell oval or trigonal; umbo usually anterior or II b Mantle margin anterior to branchial aperture posterior to middle; valves may have very fine carunculate, papillose, andlor formed into flaps concentric lines, but never deeply incised rings ~ or thickened pads; marsupium restricted to two or fewer cardinal teeth in each valve .... posterior half of outer demibranchs, never Sphaeriidae (See separate section on page 20.) formed within inner demibranchs; male and 3a Hinge plate completely edentulous; anal aper- female shells usually sexually dimorphic ...17 ture without papillae .4 12a Soft tissues usually pigmented vividly red or 3b Pseudocardinal teeth, lateral teeth, or both pre­ orange; all four demibranchs form marsupium; sent on hinge plate although sometimes vesti­ rare in most localities ...."Fusconaia masoni gial; anal aperture with or without papillae ..6 12b Not as above; marsupium restricted to outer 4a Umbo not elevated above dorsal margin; shell demibranchs 13 usually less than 120 rnrn in length 5 l3a Length/height ratio usually less than 1.8; shell 4b Umbo elevated above dorsal margin; shell often subtriangular or subquadrate; periostracum 120 mm or larger Anodonta cataracta usually centrally smooth, shiny .Elliptio 5a Ventral margin straight or slightly convex, sub­ congaraea parallel with dorsal margin; length/height ratio I3b Length/height ratio usually greater than 1.8; usually greater than 2.0; periostracum with shell lanceolate, rhomboidal, or trapezoidal; broad green rays .Anodonta imbecillis periostracum smooth or rough 14 5b Ventral margin noticeably convex, divergent 14a Sculpture including weak plications traversing from ptane ofdorsal margin; length/height ratio disk obliquely and weak subradial ridges on usually less than 2.0; periostracum with narrow posterior slope .Elliptio fraterna green rays .Anodonta couperiana 14b Not as above 15 6a Mantle margin at anal aperture lacking distinct 15a Length/height ratio usually greater than 2.5; papillae (smooth or crenulate) 7 shell distinctly lanceolate . .Elliptic lanceolata 6b Mantle margin at anal aperture with distinct, 15b Length/height ratio usually less than 2.5; shell well formed papillae 11 rhomboidal or trapezoidal 16 7a Lateral teeth present on hinge plate 8 16a Shell distinctly trapezoidal; periostracum usu­ 7b Lateral teeth absent from hinge plate 9 ally quite rough, rarely shiny anywhere on 8a Branchial papillae dendritic; periostracum with valve: egg masses in marsupium narrowly elon- satin-like texture, unrayed; pseudocardinal teeth gate, slightly broader ventrally Elliptio chunky, serrated; hinge plate lacking interdental complanata projection in left valve Uniomerus 16b Shell subrhomboidal; periostracum often with tetralasmus slight sheen medially, but without gloss on an­ 8b Branchial papillae simple (unbranched); per­ terior or posterior slopes; egg masses in mar- iostracum may be smooth, shiny, or slightly supium broadly oval Elliptio icterina roughened, but not with satin-like texture, often 17a Mantle margin anterior to branchial aperture with distinct rays; pseudocardinal teeth thin, carunculate in female; shell rarely exceeding 35 lamellate; hinge plate with interdental projection mm in length Carunculina pulla in left valve *Lasmigona subvirdis 17b Mantle margin anterior to branchial aperture 6 papillate, flap-like, or forming a thick pad, but edentulate, or with either pseudocardinal or lateral teeth not carunculate; shell frequently exceeding 35 or both; ligament opisthodetic and parvincular; mm in length 18 periostracum usually conspicuous; a sheet of tissue 18a Mantle margin anterior to branchial aperture almost completely separates excurrent and incurrent papillate in female; shell rarely exceeding 70 mm mantle cavity; gills with distinct interlamellar septa that in length 19 parallel gill filaments and form watertubes, some or all of 18b Mantle margin anterior to branchial aperture which become brood chambers (marsupia) for ova and flap-like or formed into a thickened pad; shell larvae; larvae (glochidia) parasitic on vertebrates, usually often exceeding 70 mm in length 20 fish. 19a Periostracum with wide green rays occasionally interrupted by growth rests; sexual dimorphism SUBFAMILY UNIONINAE Swainson 1840 weakly expressed Vil/osa vibex DIAGNOSIS: Marsupium occupying entire outer 19b Periostracum with narrow green rays often in- demibranchs; demibranchs only moderately distended terrupted by broad yellowish background areas; when filled with ova and/or larvae; anal aperture sexual dimorphism well expressed ....Villosa papillate although papillae may be very short; delumbis pseudocardinal and lateral teeth present; glochidia oval 20a Adult shell large, heavy, subovate (female) to to subovate, with or without hooks. subtrigonal (male); periostracum smooth, yel­ GENUS Elliptio Rafinesque 1819 lowish, usually lacking rays; mantle anterior to branchial aperture flap-like Lampsilis DIAGNOSIS: Shell moderately to greatly elongated cariosa (length/height ratio) varying from 1.50 to at least 4.0); 20b Adult shell moderately large, moderately thick­ longitudinal axis generally straight. Beaks low, ened, subrhomboidal; periostracurn rough, some­ inequilateral, anterior, and prosogyrate. Ligament what satin-like, brownish or reddish, usually prominently elevated. Periostracum well developed and with faint rays; mantle anterior to branchial darkly colored in adults, often rayed in juveniles. aperture forming a very darkly pigmented, Dentition consisting of 2 pseudocardinal teeth and 2 thickened pad, and an anterior, ribbon-like flap lateral teeth in left valve, I or 2 pseudocardinal teeth ...... Lampsilis radiata splendida. and I lateral tooth in right valve. Anal papillae present; simple branchial papillae usually dominant, but dentritic branchial papillae sometimes present, occasionally TAXONOMIC CRITERIA numerous; papillae absent along mantle margin anteriad from branchial aperture. Dorsal margins of inner Most of the terms employed in the descriptions below lamellae of inner demibranchs not completely fused to are defined in the glossary at the end of this paper and visceral mass. Eggs 'white; glochidia without hooks, are illustrated in figures following the glossary. In each usually expelled from marsupium in compacted masses systematic description, two meristic shell ratios are (ovisacs). given: length/height and height/inflation (= breadth). In order to standardize these values to fascilitate TYPE-SPECIES: Unio nigra Rafinesque 1820 comparison, the dimensions of length, height and (~ Elliptio crassidens (Lamarck 1819». inflation were measured at consistent locations on all Elliptic complanata (Lightfoof 1786) shells (see Figures 2 and 4). Vernier calipers were used (Plate I, Figure I; Map 3) for measurements. Length was taken as the maximum anterioposterior elongation of the shell. Height and DIAGNOSIS: Shell up to 140 mm in length; elongate, ~ inflation were measured at the position of the umbo trapezoidal; mean length/height ratio 1.96 (N 52, S.D. crest, immediately posterior to the umbo origin (see = 0.15, range 1.74 to 2.84); valves usually flattened or Figure 4). This does not always correspond with slightly inflated, sometimes moderately inflated; mean ~ maximum height or inflation as can be seen in the height/inflation ratio 1.68 (N = 39, S.D. 0.17, range figures. Hence, any future measurements must be taken 1.3 to 2.1). Anterior end smoothly rounded; posterior exactly as indicated if comparisons with the present end higher and trapezoidal, sometimes biangulate; values are desired. ventral margin straight to noticeably arcuate; dorsal margin slightly arched but appearing parallel or subparallel to ventral margin, giving emphasis to DESCRIPTIONS OF THE BIVALVIA trapezoidal shape of shell. Umbos low, uninflated, frequently eroded in larger specimens; beak sculpture SUPERFAMILY UNIONACEA Thiele 1934 when not eroded, of low concentric loops subparallel to FAMILY UNIONIDAE Fleming 1828 growth lines. Posterior ridge faintly double. DIAGNOSIS: Freshwater bivalves or clams with Periostracum in young specimens brownish, yellowish, equivalve shells usually larger than I em in length; hinge or greenish, sometimes with faint rays over entire 7 surface; periostracum in adults brown to black, usually mid-May. Sperm enter the female mantle cavity through with strongly elevated growth lines over entire shell. the incurrent aperture. Simultaneously eggs are moved Pseudocardinal teeth in left valve small, serrated; single from the ovary via gonoducts to the supra-branchial right pseudocardinal serrated, but a vestigial tooth may chamber where fertilization normally occurs. Matteson occur slightly anterior to prominent pseudocardinal; (1948a) has observed fertilization in gill marsupia, and, lateral teeth with granulated surfaces. Pallial line often in one instance, sperm "in the ovarian ducts leading to loops posteriad to posterior adductor muscle scar with the suptrabranchial chambers." Fertilization occurs at posteriad extension usually less than one-fourth total the primary oocyte stage and eggs fertilized in the length of muscle scar. Nacre purple, copper orange, or supra-branchial chambers are moved into water tubes' of pink, rarely salmon or iridescent white. gill marsupia in the outer demibranchs of the gills. Branchial and anal papillae mostly unbranched, Details of cleavage and pre-glochidial development are distinctly elevated, moderately to heavily pigmented. given by Matteson (I948a). Briefly, development from Glochidial masses in marsupium compacted into narrow zygote to mature larvae requires approximately one elongate masses (ovisacs) along most of length and month in the gill marsupium. Each water tube contains height of outer demibranch, ovisacs may be expelled hundreds of developing larvae which are loosely bound from marsupium intact as white narrow elongate wafers. together in white "ovisacs." If female clams are Sexes separate, shell without sexual dimorphism. disturbed during the brooding period by sudden TYPE LOCALITY: Restricted to Potomac River, temperature changes, toxic substances in the water, Washington, D.C. by Johnson, 1976. rough handling or other factors, they often release the TYPE: Probably lost (Johnson, 1970,fide Dance, ovisacs, The ovisac of E. complanata is distinctively 1966). shaped, being long, narrow and slightly broader DISTRIBUTION: This is one of the most common of ventrally. This is in direct contrast to the shorter, the Atlantic Slope unionids ranging from central Georgia broader, more oval ovisac of an aberrant Mill Creek to northern Canada and westward to Lake Superior. population of Elliptio , which we presently refer to as E. Matteson (I948a, 1948b) discusses the general icterina (see below). The shape of the aborted ovisac distribution of the species. reflects the shape of the water tube cavity and, ECOLOG Y: E. complanata seems to prefer sandy or according to Fuller (1971, 1972), the evolutionary history sandy-mud substrates in moderately to fast flowing of the genus. Matteson (l948a) reports that expulsion of streams. However, it can be found in almost any ovisacs represents abortion of larval stages rather than freshwater habitat from organically rich pond bottoms to the primary mechanism of release. He shows that clean sandy bars in sandy rivers. It has even been ovisacs contain larvae in various stages of development. successfully introduced into new lentic habitats (see Glochidia are brooded until "mature," when they are Smrchek, 1971, concerning the introduction of E. released individually via the suprabranchial chamber and complanata in Douglas Lake, Michigan). It can be anal aperture. The actual mechanism of transport to the especially abundant in some parts of the Savannah suprabranchial chamber is unknown. However, as River. where giant specimens in excess of 140 mm have glochidia are ejected from the anal aperture, they are been found. At SRP, E. complanata shares a common accompanied by mucous strands which attach to habitat with E. icterina, where the two species whatever they contact in "cobweb" structures. frequently coexist in approximately equal numbers. See, Apparently this facilitates encounter with fish hosts. also, Matteson (l948a, pp. 715-716). An individual glochidium of E. complanata is a small, LIFE HISTORY: Most of the information presented oval, bivalved, hookless larva approximately 200 I-' in here is from Matteson (l948a), who describes the life length and slightly less in height. Unionid glochidia history of E. complanata in considerable detail. The usually must attach to a suitable fish host for general pattern of development demonstrated by this development to proceed, although some species (e.g., species is very similar to that of many other unionids Anodonta imbccillis fide van der Schalie, 1970) appear to and can serve as a guide for the group. Hence, more be facultative parasites, which may develop directly information is presented here than in subsequent "Life without encystment. Obligatory parasitic glochidia such History" sections. In the latter, those features which as those of E. complanata usually attach to and encyst tend to differ from this species will receive the greatest on fish gills. Some species (e.g., Anodonta spp.) have attention. hooks on the larval shell and can attach to the fins of Sexes are separate in E. complanato as is the typical fishes. Glochidia are apparently host specific, but case in the unionids. Matteson (I948a) found viable host-glochidia relationships are far from being well sperm present in the testes throughout the year, with the known. There is considerable controversy concerning sperm count increasing during late spring. Males begin the "parasitic" period of the unionid life cycle, to release sperm into surrounding waters via the anal particularly whether the encysted glochidium actually aperture in late April. Release continues through derives nutrition from the host fish or merely uses the mid-June. with the peak sperm release occurring in fish as a dispersal mechanism. Fuller (1974) reviews the 8 problem and presents a considerable bibliography. Those (pH 8.0), the two species distinctly separate with the fish that serve as glochidial hosts of SRP mussels are homozygous product of E. complanata migrating listed in a separate section in each species discussion consistently faster than the homozygous product of E. (see below). icterlna. There are other differences that can also be Matteson (l948a) reports the encysted stage in E. shown by electrophoresis. complanata to be approximately 18 days. During the end In summary, although E. complanata and E. icterina of this period, the glochidia undergo a metamorphosis in are the most abundant species of the SRP, their absolute which there is considerable alteration of internal identification often remains elusive, even for experts (cf. anatomy. The clam then drops from the fish host to Fuller, 1971). Anyone requiring precise specific begin independent development. This period of the life identification should always consult a knowledgeable cycle of most mussels including E. complunata is poorly malacologist for advice and assistance. understood. Hatteson (I948a) was able to hold juvenile Elliptio icterina (Conrad 1834) clams 35 days after the glochidial stage, with the shell (Plate I, Figure 2; Map 2) increasing from 208 I" to 840 1". Most information on the growth of unionids concerns specimens of at least I em DIAGNOSIS: Shell reaching 86 mm in length; or more in length. Matteson (I948a) suggests that the elongate, sublanceolate to subtrapezoidal: mean greatest amount of growth in E. complanata occurs length/height ratio 2.12 (N = 59, S.D. ~ 0.23, range 1.81 during the third growing season and the next greatest in to 3.49); values moderately inflated; mean the second growing season. The amount of shell material height/inflation ratio 1.49 (N = 59; S.D. ~ 0.15, range deposited diminishes with age with little appreciable 1.00 to 1.81). Anterior end smoothly rounded; posterior growth of the shell occurring after the twelfth year end often pointed, sometimes biangulate; ventral margin (Matteson, I948a). Sexual maturity is apparently reached slightly convex, rarely arcuate; dorsal margin straight to in the second or third year. junction with posterior margin where the junction is GLOCHIDIAL HOSTS: The yellow perch, Perea often noticeably angulate; dorsal and ventral margins fiavescens has been reported to harbor glochidia of E. usually not parallel or subparallel for most of their complanata (Lefevre and Curtis, 1912; Matteson, 1948a) lengths, so shell rarely presents rhomboidal shape. as has the banded killifish, Fundulus diaphunus (Wiles, Umbos low, slightly inflated, frequently eroded in larger 1975). P. fiavescens is known to occur commonly in specimens; beak sculpture when not eroded, of several waters throughout the SRP (McFarlane, 1976). concentric elevated loops which are subparallel to ADDITIONAL REMARKS: Elliptic complanata and growth lines and slightly tuberculate posteriorly. E. icterina are the most common species of unionids Posterior ridge slightly to distinctly double. Periostracum encountered in this area. They are also frequently in young specimens as in E. romplanata; adult difficult to distinguish, especially on the basis of shell periostracum often semi-polished on central shell, material alone. E. icterina tends to be somewhat smaller blackish or brownish black; infrequently with roughly and more pointed and to have a smoother shell than E. formed and elevated growth lines. Hinge teeth typical of complanata. The latter species usually possesses a rough genus, left pseudocardinals small, equal in size; right periostracum and a more quadrate or rhomboidal shape. pseudocardinals usually double with right anterior None of these differences is consistently reliable. The pseudocardinal almost vestigial; laterals with most positive means of identification is the nature of the granulations. Pallial line often curves posteriad to marsupia and the contained ovisacs (see Life Cycle, posterior adductor scar, but rarely extends posteriad above). Unfortunately, the ovisacs are formed only more than one-half length of posterior adductor scar. during summer months. Nacre iridescent white, pink, salmon orange, or purple. Fuller (1971) suggests that the pigmentation of anal Branchial and anal papillae mostly unbranched, very and branchial apertures of E. complanata is darker than lightly to moderately pigmented. Olochidial masses in that of E. icterina, We have not found this to be a marsupium inflated and broadly oval in shape, may be reliable criterion for differentiating the species. Although expelled intact from marsupium as white broadly E. complanata tends to have more darkly pigmented elliptical wafers. Sexes separate. shell without sexual apertural regions, there is considerable variability. Many dimorphism. E. icterina, including Mill Creek populations (see below) TYPE-LOCALITY: Muddy shore, Savannah River, and those from other localities on and off the SRP have opposite Augusta, Georgia. been observed with very darkly pigmented anal and TYPE: Holotype, Academy of Natural Sciences of branchial apertures. Philadelphia, 41381 figured by Johnson, 1970, Plate 9, Electrophoretic techniques can be employed to Figure 3. differentiate the species (M. Smith, J. Hagan and J. DISTRIBUTION: From the Escambia River system of Britton, unpublished data). For example, when the Alabama and Florida eastward through Florida and enzyme system Phosphoglucomutase (POM) is examined northward along the eastern Atlantic slope to the White using starch gel electrophorsis on a tris-citrate buffer Oak River, North Carolina. 9 ECOLOGY: In the region of sympatry (which includes At any rate. introduction of new taxa is inappropriate the SRP), E. ictcrina and E. complanata frequently in a handbook such as the present report. We have share similar habitats and can be collected side by side emphasized the peculiarities of "the Mill Creek 'Elliptio'" in streams, rivers, or lakes. Both species are usually simply in order to acquaint SRP scientists with this most abundant in small fast-flowing streams where they zoological curiosity in their midst and to encourage its generally lie partially buried along stream banks or on further study and conservation. bars. Like E. complanata, E. icterina may be very This last point is of great importance. The Mill Creek abundant in some localities in the Savannah River, but Elliptio is proposed as a population of special concern in rarely attains the size reached by some E. complanata South Carolina. As long as the SRP remains a National there. The Mill Creek population (see Additional Environmental Research Park, there will be little or no Remarks, below) occurs in a shallow, narrow stream danger that the public will disturb this population. There that is only a few em deep except in occasional "pools" is a very real potential danger, however, that SRP (perhaps 30 em in depth) close to its banks. Mill Creek investigators themselves may unwittingly harm it. In an is an upland SRP stream that drains a small watershed effort to forestall such mistakes, it would be well to into Upper Three Runs Creek. Its water presumably is survey SRP Elliptio. especially populations in the upper acidic during much or all of the year, but this is the Three Runs drainage, where (at least in Mill Creek) norm for higher-gradient creeks draining essentially more typical E. icterina populations are believed to be coniferous watersheds in the Savannah River basin. sympatric with the Mill Creek form. LIFE HISTORY: The life history of E. icterina is Such an investigation would best be conducted in probably very similar to that described for E. July, when the latter is known to be gravid. The valves complanata although there have been no detailed can be pried apart, slowly and gently (with thumbnail or studies. Egg masses accumulate in the marsupium during weak reverse pliers), just enough to reveal the charged June and July. The glochidium is hookless, oval and marsupium (if, of course, the specimen in hand is a very similar in appearance to that of E. complanata. See female). If the marsupium is fully charged and if it is the discussion under E. complanata for differences of obese and restricted the median halves of the outer marsupial structure and shape of ovisacs. demibranch, the specimen belongs to "the Mill Creek GLOCHIDIAL HOSTS: Unknown Elliptio"; if the specimen is a male or a barren female, ADDITIONAL REMARKS: The difficulty of this test cannot be performed, and field identification distinguishing E. icterina from E. complanata has been (i.e., without killing the animal) is not practicable unless, discussed in the remarks of the latter species, which of course, shell characters will serve, as often is the case should be consulted by the reader. with E. congaraea (Lea) and E. complanata (Lightfoot). The specimens of E. icterina inhabiting Mill Creek Finally, such surveillance, conducted with utmost display some characteristics which may justify caution, would do much to clarify the taxonomic status recognition of this population as (at least) a subspecies (and thus the legal status, if any) of what we are calling differing from the typical icterina. The marsupium of the "the Mill Creek Etliptio": We realize that this animal Mill Creek E. icterina is far more obese than is might well prove to be only a local abbe ration of E. characteristic for the species, and it is restricted icterina, but even in this case the surveillance would primarily to the median one half of the outer have been fruitful in providing knowledge of a creature demibranch. that, under any circumstances, is highly unusual and Most students of Nearctic Naiades have agreed that requires conservation in the interest of further study and Simpson (1900, 1914) and Ortmann (1910. 1911, 1912, the genetic richness of the molluscan fauna. 1916) were justified in interpreting marsupial type as the The discussion of E. ictertna by Fuller (1971) refers most important factor in unionid classification. Indeed, exclusively to the Mill Creek population. Hence, many discovery of a novel kind of marsupium has regularly of the statements attributed to E. icterina as a whole by been taxonomically recognized by erection of a new Fuller (1971) are restricted exclusively to this single genus. There is precedent, then, for also regarding the population, including figures of the marsupial structure. underscribed Mill Creek '"Elliptio '" as the type species Fuller (1972) described a new species, Elliptio of an undescribed genus, on account of the restriction of marsupiobesa from the Cape Fear River, North its marsupium to the median water tubes of the outer Carolina, and suggested that this new species is closely demibranchs. (This character is otherwise known only in related to E. icterina. the monotypic genus Hcmistena of the naiad biogeographic Cumberlandian province (Ortmann, 1918; Elliptio lanceolata (Lea 1828) Neel and Allen, 1964; van der Schalie and van der (Plate I, Figure 4; Map 5) Schalie, 1950). On the other hand, there is no reason to DIAGNOSIS: Shell up to 140 mm in length; assume that Elliptio cannot be an exceptional case, noticeably longer than high, mean length/height ratio 2.6 where more than one marsupial type may have arisen (N = 26, S.D. = 0.37, range 2.05 to 4.02); valves within the same genus. moderately inflated; mean height/inflation ratio 1.66 (N 10 = 26, S.D. = 0.12, range 1.43 to 1.83). Anterior end There is a closely related species, E. shepardiana smoothly rounded; posterior end frequently pointed, (Lea 1834), in the Altamaha River system where it is lanceolate, slightly biangulate in larger specimens; sympatric with E. lanceolata. Considering the large ventral margin straight or slightly arcuate, junction with amount of variability in E. laneeolata in the Savannah posterior margin noticeably angular; dorsal margin and River drainage, one must question whether E. ligament area elongate, slightly convex, subparallel to shepardiana is a distinct species and not an ecotypic ventral margin, junction of dorsal and posterior margins variation. Needless to say, E. shepardiana is quite obtusely angular. Umbos low, slightly inflated, distinctly singular with respect to shell elongation with a anteriad, frequently eroded in larger specimens; beak length/height ratio frequently exceeding 4 and sculpture similar to that of E. icterina. Periostracum approaching 6. growth lines finely concentric, color in young specimens Elliptio eongaraea (Lea 1831) similar to that described for E. complanatu, brownish or (Plate I, Figure 3; Map 3) blackish in adults, central area of shell smooth or subpolished, closely spaced and elevated growth lines DIAGNOSIS: Shell up to 101 mm in length; slightly may be produced on periostracum around shell elongate, sub-triangular, mean length/height ratio 1.7 (N periphery. Pseudocardinal teeth small, left posterior and = 29, S.D. = 0.13, range 1.45 to 2.12); valves noticeably right anterior pseudocardinals poorly elevated or inflated; mean height/inflation ratio 1.5 (N ~ 29, S.D. vestigial, surface of lateral teeth granulate. Pallial line ~O.II, range 1.06 to 1.64). Anterior end smoothly passes distinctly posterior adductor scar, then passes rounded to subangular; posterior end produced, pointed dorsally often as much as two-thirds length of posterior posterioventrally, ventral margin slightly convex; dorsal adductor scar before joining it. margin and ligament area short, slightly convex, not Branchial and anal papillae mostly unbranched, parallel with ventral margin. Posterior ridge prominent to distinctly elevated, lightly to moderately pigmented. subprominent, secondary ridge may occur; posterior Glochidial masses in marsupium very narrow, consisting slope frequently with short bars or ridges crossing of one, two, or occasionally three layers of larvae, growth lines. Umbos moderately elevated, frequently extend 'Mh the length of outer dernibranch, being absent eroded in larger specimens, located in anterior third of in ventral-most portion. shell. Periostracum smooth, yellowish or brownish and TYPE-LOCALITY: Tar River, Edgecombe County, often with greenish rays in young specimens; becoming North Carolina. yellowish brown to chestnut in larger shells, polished to TYPE: Holotype, National Museum of Natural subpolished, sometimes with very fine radial History, 85905, figured in Johnson, 1970, Plate II, crenulations on central shell area; thin elevated Figure 2. concentric growth lines more apparent at anterior end DISTRIBUTION: Escambia and Apalachicola River and on posterior slope. Right pseudocardinal teeth large, systems in Florida and Alabama, but not extending to chunky, serrated, subequal; left posterior pseudocardinal peninsular Florida, and from the Satilla River system, large, serrated, more prominent than left anterior Georgia, northward to the Susquehanna River system, pseudocardinal which may sometimes appear vestigial; Pennsylvania. lateral teeth short, with granular surfaces. Pallial line ECOLOGY: E. lanceoluta is primarily a stream or usually not produced posteriad to posterior adductor river mussel found in many of the same localities as E. scar. Nacre white or salmon, slightly irridescent. icterina or E. complanata. It is only rarely taken from Simple and dendritic papillae produced at branchial lakes, apparently preferring flowing water to calmer aperture; anal papillae short, lightly to moderately conditions. pigmented. Nature of gravid marsupium unknown. LIFE HISTOR Y: This species produces marsupial egg TYPE-LOCALITY: Congaree River, South Carolina. masses during the early summer from late May to early TYPE: Holotype, National Museum of Natural July. Egg masses are very narrow and extend 5/sth the History, 85693, figured in Johnson, 1970. Plate 5. Figure height of the dernibranch. These are distinguishing I. features separating E. lanceo/ata from E. icterina, which DISTRIBUTION: From the Ogeechee River system, has a shell sometimes of similar shape. Glochidia are Georgia to the Cape Fear River system, North Carolina. hookless, oval, and typical of the genus. ECOLOGY: Although E. congaraea has been GLOCHIDIAL HOSTS: Unknown. collected from lower Three Runs Creek at Donora ADDITIONAL REMARKS: There is considerable Station, the species is apparently best adapted for larger variability in the length of E. lanceolata. River rivers. It is commonly found on sand bars along the specimens tend to demonstrate more elongate forms Savannah River. than specimens collected from smaller streams or LIFE HISTOR Y: There is apparently no published creeks. In the latter instance, the shell shape of E. information on the life history of E. congaraea. Many lanceolata approaches that of E. icterina, and females were collected in June, 1977, during field work identification can be difficult. for this report, but none were found with larvae in the II gills and only a few were found with eggs in the gonads. TYPE: The type specimen of Unio fraternus (Elliptio Ortmann (1912) reports larvae in the gills of a closely fratema] is the holotype, NMNH 85396. related species, E. crassidens, in mid-June. Possibly E. DISTRIBUTION: The known (or supposed) congaraca may hold larvae in the marsupium only a geographical distribution of Elliptio fraterna is confined very short time before release. to the Chattahoochee and Savannah Rivers of Georgia GLOCHIDIAL HOSTS: Unknown and/or South Carolina. REMARKS: Patrick et al. (1966) report E. incrassutus ECOLOGY: In the mainstem Savannah River, Elliptio from the Savannah River in the vicinity of the SRP. frutema has been taken only from sand bars beneath They are using this junior synonym of E. crassidens one or two feet of water. (Lamarck 1819) erroneously in reference to E. LIFE HISTORY: Nothing is known about the life congaraea. history of Elliptio fraterna . E. congaraea differs in several ways from the species GLOCHIDIAL HOSTS: Nothing is known about the of Elliptio discussed above, even though it presumably is larval host(s) of Elliptio fraterna . a member of the same subgenus. For example, it has a ADDITIONAL REMARKS: The 1972 discovery by more inflated, thicker shell. The reproductive period for one of us (SLHF) of conchologically at least putative this species apparently is not similar to that of E. Elliptio fraterna in the Savannah River close to SRP is complanata. E. icterina, or E. lanceolata, The species the cause of admitting this poorly understood species to often displays at least some dendritic branchial papillae, the present report. If, as we believe, this record is despite Fuller's (1971) indication that dendritic papillae authentic, it is the only recorded capture of living E. are absent. We believe that E. congaraea should receive fraterna since the species' original description almost further study, particularly comparative soft-part analysis 130 years ago. These data are sufficient demonstration of with other Elliptio species. It and closely related this species' natural rarity in at least the Atlantic congeners such as E. crassidens (which is the type drainage. species of Elliptio) may prove to be sufficiently distinct Uniomerus from the complanata-icterina-lancrotata group that the GENUS Conrad 1853 latter series might require subgeneric distinction. DIAGNOSIS: Shell moderately elongate, rhomboidal, longitudinal axis generally straight. Beaks low, Elliptio frutcrna (Lea 1852) inequilateral, anterior, and prosogyrate. Ligament (Figured by Johnson, 1970. Plate 7) elongate. slightly to moderately elevated. Periostracum DIAGNOSIS: Shell moderately elongate and laterally very well developed, clothlike, dark in adults, unrayed. compressed; sculpture consists of weak plications Dentition consisting of 2 pseudocardinal teeth and 2 running obliquely across the disc and of weak subradial lateral teeth in left valve, and one pseudocardinal and ridges on the posterior slope; periostracum is brownish one lateral tooth in right valve. Anal papillae short or yellow. appearing as crenulations but never completely absent; Incurrent papillae commonly are at least bifid, and branchial papillae dendritic; papillae absent along mantle dark pigment of mantle margin at incurrent aperture margin anterior to branchial aperture. Inner surface of extends conspicuously for a short distance anteriad. inner demibranchs not fused to visceral mass; TYPE-LOCALITY: Lea (1852) based his original marsupium restricted to outer demibranchs. Glochidia description of Unio fraternus upon populations from without hooks, held in marsupium in narrow masses. Georgia in the Chattahoochee River of the Apalachicola TYPE-SPECIES: Unio tetralasmus Say 1831, River basin in the naiad Apalachicolan biogeographic subsequent designation by Simpson (1900). region and from Georgia and South Carolina in the REMARKS: The genus is considered monotypic by Savannah River of the Savannah River basin in the Johnson (1970 and 1972) and Fuller (1971). There are naiad Atlantic drainage biogeographic region (see van marked morphological differences between Atlantic slope der Schalie and van der Schalie, 1950). However, a and Interior Basin populations which Johnson ascribes Chattahoochee specimen is the figured type. Therefore. to ecophenotypic variation. Valentine and Stansbery conchologically relevant populations of the Savannah (1971) have a more liberal interpretation ofthe number and of any other Atlantic drainage basins that may of species in this genus, stating that there are at least become involved cannot unequivocally be attributed to two and possibly more. Based upon differences in shell U. fraternus until living (or well preserved) morphology, one is tempted to agree with the latter Chattahoochee River specimens become available for authors that at least two species can be recognized, with comparison to extant Savannah River materials. As a the populations of the Savannah River being atypical of result, we can only assume, on the basis of the specimens from the Gulf Coastal drainages. Until a conchological evidence, that our Savannah River detailed examination of soft-part morphology is made, specimens are true Unio fraternus, Johnson (1970) was however. we are reluctant to differentiate the two shell the first to ascribe U. fraternus to Elliptio as E. forms as distinct species, and follow the more fraterna. conservative positions of Fuller and Johnson. 12 Uniomerus tetralasmus (Say 1831) for life." If stranded by dropping water levels in drying (Plate I, Figure 6; Map 4) streams or ponds, this mussel will bury itself deeply in the moist substrates to avoid dessication. One of us DIAGNOSIS: Shell up to 114 mm in length, elongate, (JCB) has collected U. tetralasnius from a north Texas rhomboidal; mean length/height ratio 1.73 (N ~ 12, S.D. farm pond which had been drained at least one month ~ 0.11, range 1.50 to 1.88); valves moderately inflated; prior to the date of collection. The surface of the drained mean height/inflation ratio 1.59 (N ~ 12, S.D. ~ 0.13, pond was firm enough to walk upon without sinking into range 1.38 to 1.81). Anterior end smoothly rounded; mud, yet numerous living specimens were found at the posterior end high, trapezoidal, relatively straight from bottom of deep cracks caused by the drying substrate. near termination of hinge teeth to subangular Simpson (1893), Baker (1928), and others have published posteroventral margin; ventral margin slightly convex, similar observations. usually not arcuate; dorsal margin almost straight to LIFE HISTORY: Only the outer demibranchs are slightly curved, angular at junction with posterior marsupial in this species. Female marsupia were bare margin. Umbos low, uninflated, frequently eroded in during June, 1977, lacking either eggs or larvae, but larger specimens; beak sculpture when present several females were collected with eggs in the gonads. consisting of 6 to 8 low concentric loops oblique to GLOCHIDIAL HOSTS: Unknown. growth lines on posterior slope. Posterior ridge broadly REMARKS: Valentine and Stansbery (1971) consider rounded; posterior slope wide with one or two radiating the South Carolina populations of Uniomerus to be U. finely incised lines. Periostracum usually dark brown or obesus (Lea 1831). They consider this species a shorter, black, heavy, often with a cloth like sheen. more inflated form which differs from the type-species, Pseudocardinal teeth in left valve serrated, subtriangular U. tetrulasmus . Detailed examination of soft tissue or triangular; single left pseudocardinal slightly larger, morphology or cytochemistry may prove that U. obesus serrated; trace of a vestigial pseudocardinal may appear is a valid name. anterior to large left member; laterals typical of genus, sometimes faintly granulate. Pallial line extends slightly SUBFAMILY ANODONTINAE Swainson 1840 to distinctly posteriad to posterior adductor scar, from DIAGNOSIS: Marsupia occupying entire outer one-eighth to one-third length of scar. Nacre of valve demibranchs, demibranchs greatly distended when filled interior white, bluish lavendar, coppery purple, pink or with ova and/or larvae; secondary partitioning of the purple. water tubes present; anal aperture without papillae; Anal papillae short and crenulate; branchial papillae lateral teeth, pseudocardinal teeth or both frequently mostly dendritic, some simple; anal and branchial reduced or absent; umbonal sculpture usually a series of apertures moderately pigmented; papillae absent along raised double loops; glochidia ovate or subtriangular ventral margin below and anterior to branchial aperture, with hooks. mantle frequency exhibits a faint gray band along ventral margin. Glochidial masses in marsupium very narrow, GENUS Alasmidontu Say 1818 elongate rods along most of length and height of outer DIAGNOSIS: Shell inequilateral, elliptical or demibranch. Sexes separate. sexual dimorphism not rhomboidal, inflated moderately heavy posterior ridge clearly indicated in shell. usually prominent. Umbos inflated, anterior, and TYPE-LOCALITY: Bayou St. John, Louisiana. prosogyrate. Ligament short but prominently elevated. TYPE: Apparently lost, fide Johnson, 1970. Periostracum thin to well developed, darkly colored in DISTRIBUTION: Central and southern United States adults, often rayed. Pseudocardinal dentition always from the base of the Rocky Mountains to the Atlantic present; lateral dentition present, vestigial or absent; slope drainages, generally below latitude 40 degrees. when present paired laterals may be in right valve. Inner Johnson (1970) indicates this species is "noticeably surface of inner demibranchs mayor may not fuse with scarce" in the Carolinas. visceral mass epithelium. ECOLOGY: U. t etralasmns is not especially common TYPE-SPECIES: Unio hcterodon Lea 1830. in the waters of the SRP, but it does seem to be present A/asmidonta triangulata (Lea 1858) in ponds as well as streams, and frequently in fine muds (Plate 11. Figure 1, Map 4) or silts. It has been taken in Upper Three Runs and Lower Three Runs Creeks, where it avoids the swifter DIAGNOSIS: Shell elongate, subrhomboidal usually waters over sand banks, preferring instead the fine less than 60 mm in length; mean length/height ratio 1.49 organics and leaf debris traps created by slowly moving (N ~ 4, S.D. ~0.04, range 1.44 to 1.51); valves thin to side eddies. It is also present in the muds of Par Pond. moderately thickened, inflated; mean height/inflation U. tetralasmus is particularly well adapted for ratio 1.25 (N ~ 4, S.D. ~0.002, range 1.2 to 1.3). surviving drought or low water conditions for extended Anterior end rounded with most pronounced curvature periods. This ability has prompted Fuller (1971) to along dorsal half of anterior margin; posterior end describe the species as having an ' enormous tenacity distinctly pointed at termination of posterior ridge. 13 angulate at margin of posterior slope; ventral margin Savannah River drainage. The two groups can be gently curving; dorsal margin noticeably arched or differentiated in the Savannah drainage fauna by the sinuate, being most angulate just anterior to the umbo. nature of the umbo: Utterbackia has very low, almost Umbos prominent, inflated and elevated, crossed by flattened beaks; Pyganodon has inflated and elevated several distinct, broadly spaced ridges that extend onto umbos. the uppermost eighth of the shell. Posterior ridge distinctly elevated, angular; secondary or tertiary ridges SUBGENUS Utterbackia F. C. Baker 1927 may occur on posterior slope and form marginal Anodonta imbecillis Say 1829 angulations at their termination. Periostracum relatively (Plate I, Figures 7 and 8; Map 3) thin over most of shell exterior, but becoming slightly DIAGNOSIS: Shell elongate, subrhomboid, up to 80 thickened on posterior slope, light green or yellow in mm in length; mean length/height ratio 2.27 (N = 30, young specimens, becoming brown, greenish brown or S.D. = 0.18, range 2.02 to 3.08); valves very thin, black in older animals; green rays often prominent on fragile, moderately inflated; mean height/inflation ratio shell beneath periostracum. Left valve with a small, 1.51 (N ~ 30, S.D. =0.12, range 1.28 to 1.75). Anterior poorly elevated pseudocardinal tooth with a slight end smoothly rounded; posterior end subpointed to groove anterior to it and a slightly toothed interdentum angular with greatest distention in lower half; ventral to the posterior; left lateral tooth almost absent. margin slightly curving, subparallel to dorsal margin; TYPE-LOCALITY: Upper Chattahoochee River, dorsal margin almost straight, elongate. Umbos flat, not Georgia. elevated or inflated; umbonal sculpture consisting of a TYPE: Holotype, NMNH, 86249, figures in Johnson, series of distinctly raised double loops. Posterior ridge 1970, Plate 13, Figure 5. smoothly rounded; posterior slope somewhat flattened, DISTRIBUTION: Apalachicola River system to the sometimes raised into a slightly flaring wing. south, and the Ogeechee, Savannah, and Santee-Cooper Periostracum relatively thin on all parts of shell, smooth River systems on the Atlantic slope. The species is not and shiny medially, but slightly rougher on posterior common in any part of its range, and thus should slope; color tan; yellowish brown, greenish brown or perhaps be considered a threatened or endangered green; broad greenish rays common. Hinge thin, narrow, species. edentulous, ligament thin, narrow, elongate. Nacre of ECOLOGY: A. triangulata is a rare species with little shell interior bluish white to metallic steel blue. known about its ecology or life cyile. It is usually found Anal papillae absent, branchial papillae simple, in rivers or larger streams throughout its range, but unbranched, moderately pigmented. Monoecious, outer never in abundance. During June, 1977, the species was demibranchs greatly distended when charged with found at only one locality on the Savannah River. glochidia. GLOCHIDIAL HOSTS:: There have been no reports TYPE-LOCALITY: Wabash River, New Harmony, of host fish for the glochidia of Alasmidonta triangulata. Indiana (restricted by Clench and Turner, 1956). Morrison (in Clarke and Berg, 1959) reports that TYPE: Original type lost. Neotype, Senickenberg glochidia of A. calceola (Lea 1830) from the Mississippi Museum 4301, selected by Haas, 1930. system attach to a darter, Etheostoma nigrum, DISTRIBUTION: From the eastern base of the Rocky McFarlane (1976) does not report this fish from waters Mountains to the Atlantic Slope. of the SRP, but several other species of the same genus ECOLOGY: A. imbecillis is a common pond or lake are present. mussel, apparently preferring the quieter waters. It lives in sand, mud, or fine silts, but is usually absent from GENUS Anodonta Lamarck 1799 gravels or shifting sands in fast flowing streams. This is DIAGNOSIS: Shell slightly to noticeably inequilateral, the most abundant species in Par Pond and other pooled elongate, variably inflated, usually thin, fragile, posterior basins of the SRP, being common from shore to depths ridge may be present but poorly differentiated. Umbos of 8 to 10 m. The deeper water populations in Par Pond low or high, submedian to noticeably anterior. Ligament frequently produce a prominent "wing" or elevation of narrow, low and elongate. Periostracum usually rather shell material posterior to the umbo (Plate I, Figure 7). thin, variably colored in adults, often rayed. Hinge teeth A. imbecillis is very common and easily collected in totally absent. Inner demibranchs not fused to surface of the SRP lakes, where it cannot be confused with any visceral mass along most of their height. other mussel. The only similar species, A. couperiana, TYPE-SPECIES: My titus cygneus Linnaeus 1758 may occasionally coexist with A. imbecillis. Patrick et (Opinion 94 and 561, International Commission of al. (1966) report that both species were collected from a Zoological Nomenclature, 1926 and 1959). single station on the Savannah River near Johnson's REMARKS: Johnson (1970) recognized two Landing. The species can be distinguished in that the subgenera, Pyganodon Crosse and Fisher 1894 shell of A. couperiana is more inflated and the ventral (including A. cataractal and Utterbackia F. C. Baker margin is noticeably more convex than A. imbecillis , 1927 (including A. imbecillis and A. couperiana) in the which has a more elongate, streamlined appearance. 14 LIFE HISTORY: The life history of A. imbecillis 3, S.D. ~ 0.16, range 1.75 to 2.06); valves thin, light in differs from that of other mussels in several ways. The younger specimens but becoming slightly thicker in species is almost always hermaphroditic (van der older, larger shells; moderately well inflated; mean Schalie, 1970), although it is uncertain whether height/inflation ratio 1.28 (N ~ 3, S.D. = 0.07, range self-fertilization is possible in this species. It may also 1.20 to 1.35). Anterior end smoothly rounded; posterior avoid the parasitic larval stage, with larvae developing end somewhat pointed or wedge-shaped; ventral margin directly in gill marsupia (see below). The larvae are almost straight or slightly and smoothly curving; dorsal brooded during the fall and winter months and may be margin straight, subparallel to ventral margin. Umbos held in the gills as late as mid-May (Ortmann, 1909), The slightly to moderately elevated above hinge line, glochidia bear hooks, which can be used to facilitate somewhat inflated, beak sculpture having characteristic attachment to a fish host. double-loop ridges of genus. Posterior ridge broadly GLOCHIDIAL HOSTS: Clarke and Berg (1959) report. rounded; posterior slope broad, slightly depressed. that glochidia of A. imbecillis have been found in Periostracum smooth, shiny over median region of shell, association with tissues of the cyprinid Semotitus becoming rough and laminate anteriorly and posteriorly, atromaculatus, the Creek Chub. Tucker (1927, 1928) has especially on posterior slope: color yellowish brown, shown that the centrarchid Lepomis cyunellus, the yellowish green, or greenish; broad green rays common. Green Sunfish, also harbor glochidia. Both fish species Hinge endentulous, thin, narrow, except below ligament, have been reported from SRP by Mcf-arlane" (1976), but where it becomes slightly thickened; ligament poorly neither is reported from Par Pond, where A. imbecillis is elevated, thin, narrow, elongate. Nacre of shell interior very common, Thus, it is possible that additional fish white or bluish white, sometimes with a slight pinkish species act as hosts for the larvae. On the other hand, flush. there are reports that A. imbecillis glochidia are only Anal papillae absent, branchial papillae simple, facultative parasites and are capable of developing unbranched, moderately pigmented. Sexes separate. directly without the parasitic stage (e.g., Howard, 1914). TYPE-LOCALITY: Deep part of a mill dam near REMARKS: Clark and Berg (l959)present a discussion Philadelphia, Pennsylvania (locality restricted by of the anatomy of this species. Johnson, 1970). Anodonta couperiana Lea 1840 TYPE: Original type lost. No neotype designated. (see Johnson, 1970, Plate 16 and 17 for figures) DISTRIBUTION: Alabama to the St. Lawrence River along coastal drainage systems and possibly westward DIAGNOSIS: Similar to A. imbecillis except ventral along the St. Lawrence system to Michigan. margin noticeably convex and divergent from the plane ECOLOGY: A. cataracta can be found in a variety of of dorsal margin; length/height ratio usually less than habitats. It is equally common in lakes, streams, and 2.0; periostracum with narrow green rays; usually rivers, and in substrates from mud to sand. It generally noticeably globose. avoids the swifter waters of streams, seeming to prefer TYPE-LOCALITY: Hopeton, near Darien, McIntosh more slowly moving currents in protected areas of Co., Georgia. streams. It has been found in the Savannah River near TYPE: Lectotype, USNM 86673. the mouth of Lower Three Runs Creek, at Donora DISTRIBUTION: St. Marys River, Florida to Cape Station, and in Pond B. It likely also occurs in Par Pond Fear River Drainage, North Carolina. as well. It also seems to be rather abundant in the ECOLOGY: Johnson (1970) states that the species nearby Clark Hill Reservoir. prefers sandy or muddy bottoms of ponds and sluggish LIFE HISTORY: Like many of the Anodontinae, A. streams. cataracta holds larvae in the marsupium for several GLOCHIDIAL HOSTS: Unknown. months during the winter season, beginning in late REMARKS: This species was not collected in 1977, September or October (Conner, 1909). Most specimens but it has been recorded in previous collections made by discharge the hooked glochidia in May, but Ortmann Fuller from the Savannah River. (1909) reports gravid females rarely can be found as late SUBGENUS Pyganodon Crosse and Fisher 1894 as mid-July. Anodonta cataracta Say 1817 GLOCHIDIAL HOSTS: Lefevre and Curtis (1910) (Plate I, Figure 5; Map 2) report glochidia of this species from the cyprinid Cyprinus carpio, the carp, which is present at SRP DIAGNOSIS: Shell elongate, subrhomboidal, large, up (McFarlane, 1976). to 175 mm in length; mean length/height ratio 1.87 (N = REMARKS: This is A. hallenbecki Lea of Patrick et al. (1966). *McFarlane (personal communication) doesn't believe Green Sunfish have been reliably reported from SRP. In the reference cited he cites GENUS Strophitas Rafinesque 1820 Freeman for the record of this species presence in streams. McFarlane believes the record may very well be due to aberrant warmouth bass DIAGNOSIS: Shell elliptical to rhomboid moderately which he has seen here. thickened, posterior end usually pointed, hinge teeth 15 rudimentary with usually at least one vestigial tooth in TYPE: Original type lost. No neotype designated. each valve. DISTRIBUTION: Ocmulgee River, Georgia to the Neuse River, North Carolina. Strophitus undulatus (Say 1817) GLOCHIDIAL HOSTS: Unknown. Figured in Johnson, 1970, Plate 17 REMARKS: Fuller collected this species from the DIAGNOSIS: Shell to 90 mm in length, rhomboid, Savannah River. It was not collected in 1977. valves moderately inflated, inequilateral; umbos well-expanded, vestiges of one pseudocardinal tooth in GEN US Vil/osa Frierson 1927 each valve anterior to umbo; lateral teeth absent; nacre DIAGNOSIS: Shell usually small or moderate in size. bluish or pinkish. thin; greatest height always posterior to center; TYPE·LOCALITY: Schuylkill River, near Philadelphia, periostracum often distinctly rayed; umbos in anterior Philadelphia Co., Pennsylvania (restricted by Johnson, third of shell; beak sculpture distinctly of double-looped 1970). ridges; posterior ridge indistinct or broadly rounded; TYPE: Original type lost. No neotype designated. pseudocardinals and laterals present; usually narrow and DISIRIBUTlON: Savannah River, South Carolina to compressed toward hinge line; mantle margin anterior to the St. Lawrence River, Canada and westward to the branchial aperture distinctly papillate, but not forming a Mississippi and Ohio River drainages. pad or flap. LIFE HISTORY: This is another species of REMARKS: This is Mieromya Agassiz 1852, of Anodontinae which may complete metamorphosis from authors, a name preoccupied in the Insecta. glochidium to adult without the need of a vertebrate host (Johnson, 1970). Vil/osa delumbis (Conrad 1834) GLOCHIDIAL HOSTS: The Largemouth Bass, (Plate II, Figures 3 and 4; Map 5) Micropterus salmoides and the Northern Creek Chub, DIAGNOSIS: Shell with pronounced sexual Semotilus atromuculatus have been identified by Baker dimorphism, relatively thin; length up to 70 mm; mean (1928) as hosts for glochidia in this species. length/height ratio 1.93 (N = 13, S.D. ~ 0.09, range 1.80 REMARKS: This species has been collected only once to 2.12); valves moderately to greatly inflated, especially in the vicinity of the SRP, on the Savannah River. in females; mean height/inflation ratio 1.48 (N = 13, S.D. =0.14, range 1.33 to 1.75). Anterior margin SUBFAMILY LAMPSILINAE von Ihering smoothly rounded; posterior half of shell considerably 1901 taller in females than in males; posterior margin of males DIAGNOSIS: Marsupium usually restricted to subangulate with most acute curvature in posteroventral posterior half or less of outer two demibranchs, this area; posterior margin of females subtruncate ventrally region usually becoming greatly distended when filled and produced dorsally with most acute curvature in with ova and/or larvae; no secondary partitioning of dorsal third of posterior margin; posteroventral margin water tubes; lateral teeth always present but sometimes of females almost straight and oblique to anteroposterior weakly developed; pseudocardinal teeth usually present; axis of shell; ventral margin of male slightly curving; glochidia subovate or hatchet-shaped, with or without ventral margin of female descending almost straight to a hooks. point about two-thirds of the distance from anterior end, thence turning at an obtuse angle and passing almost GENUS Carl/nell/ina Baker 1898 straight to posterior termination; dorsal margin slightly DIAGNOSIS: Shell small, moderately inflated, curved with hinge plate quite thin. Ligament narrow but obovate, moderately thickened, often pointed prominently elevated. Umbos elevated slightly above posteriorly; pseudocardinal and lateral teeth present; hinge line, moderately inflated, double loop sculpture inner demibranch partially or completely free of visceral distinct in those specimens without umbonal shell mass; female with well developed caruncle on mantle erosion. Posterior ridge smoothly rounded, obscure, below branchial opening. slightly more evident in male than female; marsupium imposes a distinctive bulge on female shell anteriad from Caruncullna pulla (Conrad 1838) posterior ridge; posterior slope may bear faint traces of Figured in Johnson, 1970, Plate 17 radial lines. Periostracum thin, smooth, clothlike, DIAGNOSIS: Shell small, up to 35 mm in length, sometimes shiny on medial surface, but often laminate elongate, solid, inflated; beaks not well elevated; left on posterior slope; color yellowish or yellowish tan, valve with two pseudocardinals and two lateral teeth; becoming brown or chestnut in older specimens, shell right valve with one pseudocardinal and one lateral always bearing narrow green rays which are usually tooth; nacre usually white; female with pronounced interrupted along their length by non-pigmented areas. caruncle. Left valve bearing two thin, erect almost triangular TYPE-LOCALITY: Wateree River, South Carolina, pseudocardinals, which are closely applied to hinge line; restricted by Johnson, 1970. separated by a narrow interdentum from two thin, 16 closely spaced lateral teeth; right anterior pseudocardinal without umbonal shell erosion. Posterior ridge smoothly small, lying on hinge line; right posterior pseudocardinal rounded, obscure; posterior slope may bear faint traces larger, more projecting, and more distinctly separated of thin, slightly elevated or incised radial lines. from hinge line; narrow interdentum separates Periostracum thin, generally smooth, almost glossy on pseudocardinal area from a single right lateral tooth, medial surfaces; color greenish yellow, yellowish, Anterior adductor muscle scar moderately to deeply yellowish brown, or tan with broad green radial lines impressed; internal nacre white or bluish white, slightly which usually are not interrupted along their length. Left iridescent. anterior pseudocardinal thin, erect, triangular, spaced Inner mantle fold anterior to branchial siphon somewhat away from hinge plate; left posterior distinctly papillate in female, but may be rudimentary or pseudocardinal vestigial, two thin, narrow, closely absent in male; mantle pigmentation moderately to spaced left lateral teeth. Right anterior pseudocardinal weakly expressed. larger, erect, triangular, distinctly projecting and TYPE-LOCALITY: Small stream near Cooper River, separated from hinge plate; single, thin, relatively short South Carolina. right lateral tooth. Anterior adductor muscle scar slightly TYPE: Apparently lost (Johnson, 1970). to weakly impressed; internal shell nacre bluish white or DISTRIBUTION: From the Altamaha River system, steel blue and iridescent. Georgia, to the Neuse River system, North Carolina. Inner mantle fold anterior to branchial siphon ECOLOGY: This species was almost always found in distinctly papillate in female but may be rudimentary or association with calm eddies in fast flowing streams absent in male; mantle rather darkly pigmented. where organic detritus and leaf debris tends to TYPE-LOCALITY: Black Warrior River, south of accumulate. The most reliable method of collecting V. Blount's Spring, Alabama. delumbis in these areas is to sift the debris through one's TYPE: Holotype, ANSP, 56488a, figured by Johnson, hands, searching for shells. V. vibex, Elliptio 1970, Plate 17, Figure 10. complanata. E. icterlna, and E. lanceolata are common DISTRIBUTION: Pearl River drainage in Mississippi associates with V. dclumbis, eastward along Gulf Coastal drainages to Florida, and LIFE HISTORY: Ortmann (1912) discusses several from the Altamaha River system, Georgia, to the Cape Micromyu (~ viitosai spp., suggesting that the period of Fear River, North Carolina. brooding is during the winter. However, numerous ECOLOGY: Similar to that of V. delumbis. gravid females of this and the following species were LIFE HISTORY: See V. delumbis, collected during June, 1977. As with all Larnpsilinae, GLOCHIDIAL HOSTS: Unknown. only the posterior portions of the outer demibranchs are marsupial. GENUS Lampsilis Rafinesque 1820 GLOCHIDIAL HOSTS: Unknown. DIAGNOSIS: Shell moderate to large in size, solid, REMARKS: Although male and female shells are subovate to elongate; periostracum with or without rays; distinctly and easily differentiated, the dimorphism is not position of umbos variable; beak sculpture absent or of evident in the various computed shell ratios (e.g., the double-looped type; sexual dimorphism usually length/height) used in this study. This is largely due to prominent with female frequently more inflated and the location on the shell where measurements are taken. posteriorly truncate; pseudocardinals and laterals If. for example, height were measured more posteriorly, present, narrow, lamellar; mantle margin extended in a the dimorphism would appear in all ratios employing the prominent flap-like papillate fold or pad in female; height dimension. "eyespot" near branchial aperture often present in female. Villosu vibex (Conrad 1834) (Plate II, Figure 2; Map 5) Lampsilis curiosa (Say 1817) DIAGNOSIS: Shell weakly sexually dimorphic, thin; (Plate II, Figures 5 and 6; Map 4) length up to 60 mrn: mean length/height ratio 1.96 (N ~ DIAGNOSIS: Shell large, heavy with pronounced 6, S.D. ~ 0.05, range 1.85 to 2.01); valves moderately sexual dimorphism; length up to 140 mm in males, and inflated; mean height/inflation ratio 1.55 (N = 6, S.D. 120 mm in females; mean length/height ratio of males ~0.08, range 1047 to 1.64). Anterior margin smoothly 1.52 (N ~ 27, S.D. ~ 0.07, range lAO to 1.66); mean rounded; posterior margin somewhat pointed in males. length/height ratio of females 1047 (N = 8, S.D. = 0.10, but more broadly rounded and more elevated in females; range 1.36 to 1.67); valves greatly inflated, especially in ventral margin of males slightly convexly curved in females; mean height/inflation ratio of males 1.43 (N ~ males but almost straight or slightly arcuate in females; 27, S.D. ~ 0.07, range 1.31 to 1.58; mean height/inflation dorsal margin slightly curving, hinge plate very narrow. ratio of females 1.28 (N ~ 8, S.D. = 0.06, range 1.22 to Ligament narrow and prominently elevated. Umbos 1.38; mean length/inflation ratio of males 2.17 (N ~ 27, slightly inflated and weakly elevated above hinge line, S.D. = 0.15, range 1.93 to 2.59); mean length/inflation double-loop sculpture present in those specimens ratio of females 1.89 (N ~ 8, S.D. ~ 0.20, range 1.73 to 17 2.30). Anterior end often bluntly pointed, sometimes never been studied in detail. but it is presumably similar slightly flaring, especially in the female. acute curvature to that of several other closely related Lampsilinae (e.g.. of posterior margin more pronounced in dorsal half with L. ventricose. L. ovcuu, etc.). Females of these species ventral portion smoothly curving to join ventral margin: apparently employ the mantle flaps and "eyespots" on posterior margin extended and slightly to moderately the mantle margin as fishlures, attracting host species of pointed in male. more abrupt and almost truncated in fish for the glochidia larvae. Kraemer (1970) presents a female; ventral margin smoothly curving; dorsal margin detailed discussion of this interesting behavior. The arched. subangular with apex of arch located above eyespots are not photoreceptors. but are pigmented interdetum in left valve and near termination of right areas which mimic the eyes of other organisms. lateral tooth; ligament large. prominently elevated. The species has been described as probably Umbos inflated. raised above hinge line. frequently bradytictic (Ortmann. 1909; Conner. 1909). Almost all eroded in large specimens. Posterior ridge usually females collected in June. 1977. had glochidia or eggs in obscure. posterior slope delineated primarily by change the marsupia, in periostracal texture. Periostracum well developed. GLOCHIDJAL HOSTS: Unknown. thick. shiny smooth on anterior and lateral shell REMARKS: L. cariosa is one of several closely surfaces. but becoming dull and distinctly laminate on related species. which include L. ovata (Say 1817). L. posterior slope; color yellow. yellow brown. chestnut or dotabrucformis (Lea 1857). and L. satura (Lea 1852). reddish brown. Two serrated pseudocardinal teeth in left Admittedly, the species listed here cover a very broad valve, anterior tooth usually larger, projecting anteriad. geographic distribution. but certainly no more so than posterior tooth erect under umbo; broad interdentum in Uniomerus trtralasmus, which is regarded by some left valve with hinge plate arched in posterior third of (e.g., Johnson. 1970 and 1972; and Fuller. 1971) as interdentum; two relatively short left lateral teeth with conspecific throughout the range, In fact. U. tetralasmus lower lateral having a slightly granular face. Two displays at least as much variation as all of the above serrated right pseudocardinal teeth with the ventral tooth taken together. larger and slightly posterior to the dorsal one, dorsal For example. L. dolabrocfonnis is a species pseudocardinal sometimes sharply pointed; broad presumably endemic to the Altamaha River system and interdentum in right valve; right lateral tooth short. allopatric with L, curiosa, whose range extends prominently elevated. forming a distinct ledge on hinge southward only to the Ogeechee River system. Johnson plate. Pallial line usually does not extend beyond (1971) frequently compares L. dolabracformis to other posterior termination of posterior adductor; anterior species: 1) "Is close to L. cariosa'" 2) "resembles L adductor scar distinctly impressed. Nacre of valve eXcaVll([{S," 3) "resembles L. binominutns." He points interior white or bluish white and frequently flushed with out that Simpson's (1914) report of L. dolobracjormis pink. from the Ogeechee and Savannah River systems are Distinct. large darkly pigmented "eyespot" on each erroneous records of L curiosa, In another section mantle lobe of female just ventral to branchial aperture; Johnson (1971) suggests that L. curiosa I) "can be mantle anterior to eyespot produced into a flap of tissue confused with L. dotabraeformis:' 2) "has been most (not pad-like), lightly pigmented. Ventral margin of often confused with L ochracva.:' and. with respect to marsupium darkly pigmented. L. ovalo, 3) "while the two species are close. they are TYPE-LOCALITY: Schuylkill River. near Philadelphia. distinct." It is not surprising that Cvancara (1963) Pennsylvania (restricted by Johnson. 1947a). concluded that three members of the Lumpsilis complex TYPE: Original type lost. Neotype, Harvard from the central U.S.. L, ventricosa, L. ovata, and L. University Museum of Comparative Zoology. 178839. excarata probably represent subspecific taxa. It is selected and figured by Johnson. 1947a. Plate 19. Figure surprising. however. that subsequent workers (Johnson I. 1970; Fuller. 1971) do not formalize similar trends in the DISTRIBUTION: Northern Georgia to Nova Scotia Atlantic slope Lampsilinae. We can follow Johnson along the Atlantic slope drainages, and westward along (1970) and Fuller (1971) for the time being. accepting L. the St. Lawrence River system. curiosa as the nominal designation for the large lampsilid L'COLOG Y: L. curiosa is primarily a large river of the Savannah River near the SRP. but we also suggest species. being particularly common along sand bars of that a careful anatomical, cytochemical or biometric the Savannah River. Its range apparently overlaps study be attempted on this large. widely distributed slightly with L. orhroccu , a tide-water species common complex to resolve some of the problems encountered near river mouths. It cannot be confused with L. by a taxonomy based upon shell morphology alone. ochracea near SRP as that species apparently does not occur here. Johnson (1947a) has additional information Lampsilis radiata sptendida (Lea 1838) on the ecology and systematics of both species. L. (Plate II. Figure 7; Map 5) curiosa is only rarely found in smaller streams or creeks. DIAGNOSIS: Shell moderately large. heavy. with LIF/:; HISTORY: The life history of L. carioso has slight sexual dimorphism; length up to 120 rnm; mean 18 length/height ratio 1.89 (N ~ 21. S.D. ~0.10. range 1.72 reported for specimens collected during this study. This to 2.10); valves well inflated; mean height/inflation ratio is probably due to the use of a standard location for 1.21 (N = 21, S.D. =0.10, range 0.98 to 1.42) with little biometric measurements. difference in this ratio between males and females. L. radiata splendida cannot be confused with any Anterior end smoothly rounded or sometimes slightly other freshwater mussel at SRP. It is distinctly angular in the dorsal portion; posterior margin bluntly lampsiline and the very darkly pigmented pad before the pointed in males, smoothly rounded and less produced branchial aperture of females is distinctive. This pad is in females; ventral margin almost straight or slightly present, but developed to a lesser degree in the male. curved; dorsal margin slightly arched; ligament large, broad, elongate, prominently elevated. Umbos FAMILY CORBICULIDAE moderately inflated above hinge line, prominent. Posterior ridge rounded but distinctly formed; two or DIAGNOSIS: Usually brackish to freshwater clams three additional radial lines may appear on posterior with oval to trigonal shells from 0.5 to 10 cm in length; slope; posterior slope broad. Periostracum well hinge with well developed cardinal and lateral teeth; developed, extensively laminate but shiny on medial ligament opisthodetic and parivincular: periostracum surface, texture almost like satin. despite numerous conspicuous; sculpture of valves usually of very fine to lamellae; color reddish brown, yellowish, yellowish coarse concentric bands. green or dark brown in older shells, frequently covered with numerous green rays which are irregularly spaced GENUS Corbincula von Muhlfeld 1811 and varying in size from narrow to broad. Two elongate DIAGNOSIS: Shell with central or subcentral beaks, subequal serrated pseudocardinal teeth in left valve oval to trigonal shape; concentric sculpture usually well separated by a deep groove; anterior pseudocardinal impressed on valves; lateral teeth usually elongate and small or vestigial, posterior tooth triangular, erect; right serrate; inner demibranchs of gills form brood chamber hinge plate with an elongate, narrow interdentum; left for pediveliger larvae: some species viviparous but most lateral tooth single, straight, or slightly arched. Pallial discharge pediveliger larvae which develop directly line extends to or slightly beyond posterior termination without parasitic stage. of posterior adductor scar; anterior adductor scar deeply impressed with a distinct shell ridge immediately Corbiculo ftnmineu (Muller 1774) posterior to scar. Nacre of valve interior pink or reddish (Plate II. Figure 8; Map 2) bronze, often white centrally. DIAGNOSIS: Shell to about 65 mrn in length but Pad below the branchial aperture of female modified usually less than about 40 mrn: mean length/height ratio into a broad, darkly pigmented pad, less prominent in 1.13 (N ~ 200, S.D. ~ 0.07, range 1.00 to 1.30); valves male. Marsupium typical of genus, darkly pigmented moderately inflated; mean height/inflation ratio 1.48 (N ventrally. ~ 200, S.D. = 0.31, range 0.94 to 3.21). Shell shape TYPE-LOCALITY: Altamaha River, Mcintosh or Long roughly equilateral suboval to trigonal; posteroventral County, Georgia. margin sometimes slightly more produced than TYPE: Holotype, NMNH, 84893, figured by Johnson, anteroventral margin; dorsal margin angular; hinge plate 1970, Plate 22, Figure 5. broad with well developed dentition. Ligament broad but DISTRIBUTION: From the Altamaha River system, very short. extending from beak to near origin of Georgia, to the Santee-Cooper River system, South posterior lateral teeth, Umbos central, well elevated Carolina. above hinge plate. not elongate, often with distinctive ECOLOG Y: L. radiata splendida is usually found in blue or purple blaze in shells less than 10 mrn length; fast-flowing streams and rivers where it occurs on sand posterior ridge absent. Periostracum yellowish in young or gravel. It is not particularly abundant in fine-grained shells but becoming brown, reddish brown, or chestnut substrates. but occasional specimens may be found in brown in larger specimens. fresh periostracum even in lakes (Johnson, 1970). It is most abundant in the larger large shells often yellowish or light tan. Sculpture on creeks and river habitats near SRP. valve exterior consists of well-impressed concentric LIFE HISTORY: This is another presumed bradytictic rings with 6 to 10 rings per em. Three cardinal teeth in species in which almost all specimens collected during each valve; left posterior cardinal almost vestigial, right June, 1977, from the SRP and from the Ohoopee River, anterior cardinal closely adjacent to upper hinge plate; Georgia, had eggs in the marsupium. one anterior and one posterior lateral tooth in left valve: GLOCHIDIAL HOSTS: Unknown. two anterior and two posterior lateral teeth in right REMARKS: Although one can detect slight sexual valve: lateral teeth serrate; thickened calcareous plate dimorphism in the shell morphology of L. radiata usually underlies ligament area. Pallial line not sinusoid splendida, this could not be demonstrated at a near posterior adductor muscle scar; internal nacre statistically significant level for either of the basic shell white, lavender, or purple. Distinct anal and branchial dimension ratios (length/height and height/inflation) siphons formed; inner demibranchs modified as 19 marsupia; animals monoecious and brood developmental estimate the average individual daily fecundity of this stages (trochophore, and pediveliger larvae) in marsupia, species to be 387.0 veligers/clam and 319.8 veligers/clam TYPE-LOCALITY: Unspecified locality in China, for spring and fall reproductive periods, respectively. TYPE: Universitetets Zoologiske Museum, Brooded larvae have been known to die before release Copenhagen (no catalog number assigned), figured by from the gill marsupia, stimulating a pathological tissue Morton, 1977a, Plate I. response (Morton, 1977b). Unreleased larva are DISTRIBUTION: Originally from central and surrounded by amoebocytes which proliferate to form a southeastern Asia, this clam was first discovered in the granuloma, United States in 1938 in the Columbia River, Oregon. By The metamorphosis to a juvenile clam apparently the early 1950's, it had expanded the range along the occurs shortly after release from the marsupium. Growth west coast to southern California. It has since spread is exceedingly rapid during the first year, with shell rapidly throughout the United States and occurs across lengths of 20 mm often being attained. Thereafter, the the country from California to Pennsylvania, New Jersey growth rate gradually diminishes (Britton, et al., 1979), and Delaware, primarily south of latitude 42'. It The majority of a population apparently live two to three appeared in the Savannah River drainage between 1965 years, with some individuals surviving perhaps five or and 1973. more years. ECOLOGY: An extensive body of literature is REMARKS: C. fiuminea has been called C. developing on this potential pest species. C. fluminea manilensis, C. leana . and occasionally C. fluminalis in has been responsible for clogging water cooling systems this country, Consult Britton and Morton (1979) for a (e.g. cooling condensers) in a variety of industrial justification of C. fiuminea (Muller 1774) as the valid operations, impeding water flow in irrigation and water name for American Corbicula populations. supply canals, spoiling gravel beds used for concrete aggregate, and perhaps crowding and competing for FAMILY SPHAERIIDAE living space with native unionid mussels. Many of these DIAGNOSIS: Shells thin, often translucent, small to problems are associated with the life cycle and high minute, and oval to subtriangular in lateral outline. fecundity of this clam (see below). It is beyond the Ligament rarely external and, if so, usually partially to scope of the present paper to describe the numerous completely depressed. Cardinal and lateral teeth usually published ecological studies on this species, For the present; two or fewer cardinals in each valve. In all earlier literature, the reader is referred to Sinclair and these respects, this family differs from the Unionidae. Isom (1963) and Sinclair (1971). The Proceedings of the Organization of soft tissues in Sphaeriidae similar to First International Corbicula Symposium (1979) contains that in Unionidae (discussed above), but there is one additional literature and an extensive bibliography, difference readily useful in identification. In Unionidae During field work at SRP in June, 1977, C. fiuminea there is no fusion of the apposing mantle margins in was found to be exceedingly abundant at every locality order to separate incurrent and excurrent mantle sampled in the Savannah River. Densities in excess of apertures, whereas this occurs in the Sphaeriidae, whose 2,000 living specimens/rn- were measured. C. fiuminea apertures are separate and sometimes provided with was also found in Beaver Dam Creek, but at no other extensible mantle margin tissue so that true siphons are upland stream locality at SRP. Apparently C. fiuminea formed. was recruited into Beaver Dam Creek via the intake Again unlike the Unionidac, the Sphaeriidae brood water for the SRP 400 Production area, with specimens larvae and young in gills until early adulthood, when or larvae being transported through the system and they are released from the parent into the external deposited with the effluent entering Beaver Dam Creek. environment. where they pursue an independent Other stream localities at the SRP should be closely existence without intervention of a metamorphic period monitored with the date of first occurrence noted. In of parasitism on another organism. The Sphaeriidae view of the fact that there is exceedingly limited access apparently can forego the parasitic period. which is the to most SRP streams, an assessment of potential source of vagility for the comparatively ponderous upstream migration by this species may be possible in Unionidae, because, as much smaller, lighter, and more this area. active animals. they can depend upon mechanical LIFE HISTORY: C. ftumineu in the United States transport for extending their geographic range. appears to be a monoecious species, although Morton REMARKS: We are confident that six species of (1977a) suggests that a Hong Kong population in Plover Sphaeriidae (the pill, pea, and fingernail clams) have in Cove displays protandry. Larvae are brooded in the recent years been identified with dependable accuracy inner demibranchs. A glochidium is never formed, and from the SRP. These are Pisidium amnicum (Muller C. fiuminea never relies upon parasitism for dispersal. 1774), P. casertannrn (Poli 1791), P. compressurn (Prime Rather, the larvae are released as free-living 1851), and P. dubium (Say 1834), plus Musculium pediveligers. In most localities larvae are produced twice transversurn (Say 1829) and Eupora cubensis (Prime yearly, spring and faiL Aldridge and McMahon (1976) 1865), 20 Lawrence Tilly (SRL) contributed Pisidium amnicum however, the interested investigator must search for from Upper Three Runs (Creek) and an indeterminate them more assiduously than was required in the early congener from Par Pond. One of us (JCB) found P. seventies, when enormous beds of submerged aquatic amnicum in a Tinker Creek riffle just below Kennedy vegetation in the Savannah River provided optional Pond. The other (SLHF) and colleagues are responsible habitat for scores of macroinvertebrate species, for the other records, which have accumulated during including Sphaeriidae. During that period of obvious the about 25-year ANSP surveillance of SRP water eutrophy, P. casertanum and P. compressum were quality, especially in Lower Three Runs (Creek) and the abundant in the weed beds, and Musculium transversum Savannah River. was almost inconceivably plentiful; the mobility of these Because of their small sizes, identification of spaeriid animals means that they could exploit a dependable clams is difficult, especially in the case of Pisidium, habitat in the water column above their normal infaunal which, unfortunately, is much the most species-rich station. Eupera cubensis was rare in the weed beds, Nearctic sphaeriid genus. On the other hand, at least on presumably because its usual habit of byssal attachment the SRP, identification of Eup era cubensis (because of does not provide it adequate purchase in vegetation, but its characteristic pigmentation of shell), Musulium for many years of ANSP investigation at SRP this transversum (which has a characteristic shape), any species has been varyingly common in bank-protection Sphaerium that might be encountered (they are few and riprap along the mainstream Savannah. In recent years. refreshingly large), and P. duhium (also large, at least however, probably in response to improved treatment of for a Pisidium, and thus easily visible!) is easy or organic wastes in the upstream vicinity of Augusta, relatively so. However, the problem of the minute Georgia, the Savannah River has reverted to its earlier pisidia remains. Comprehensive taxonomic keys oligotrophy, and these extraordinary sphaeriid (Herrington, 1962; Burch, 1972, 1975a) to Nearctic populations have substantially abated with the weed Sphaeriidae exist and assuredly are vastly superior to beds, although all species can still be found. their predecessors. Nevertheless, identification of Pisidium species by shell criteria alone is hampered by the fact that they seem to be convergent among several ACKNOWLEDGEMENTS subgenera of this genus. Consequently, a key whose initial couplets dealt with soft-tissue discriminants among Support for this project was provided by the National the subgenera and that only then moved to shell Environmental Research Park program of the Savannah characters could provide a new approach to Pisidium River Plant Operations Office (US-ERDA). Several identification by markedly reducing (or perhaps even persons aided in the field collections. Major eliminating) the decisions between/among contributions were made by John Hagan, Larry conchologically similar taxa. Indeed, such a project Champagne, and Keith Daum. We are also appreciative could be the objective of a worker on the staff of (or of the field assistance rendered by Michael W. Smith, Jill visiting) the SRP National Environmental Research Glanville, Peyton Williams, Tom Graham, and Ron Park. In any case, the need for improved aids in Blessing. Jean B. Coleman prepared the distribution identifying Pisidium is evident and great. maps. Assistance for the typing of this manuscript was Opportunities for studying Pisidium and other provided by the Department of Biology, Texas Christian Sphaeriidae are prevalent at the SRP. These days, University.

21 ------

LITERATURE CITED

Aldridge, D. W. and R. F. McMahon. 1976. Population ___. 1972. An undescribed structural feature in the growth and reproduction in the life-cycle of Corbicula marsupium of Elliptio lanceolata (Lea 1828) manilensis Philippi. Abstract, Thirty-ninth Annual (Unionidae), Nautilus, 86(2-4):85-86. Meeting, Amer. Soc. Limnology and Oceanogr. ___. 1973. Fusconaia masoni (Conrad 1834) (printed in) Corbicula Newsletter, 1(4):3. (Bivalvia: Unionacea) in the Atlantic drainage of the Baker, F. C. 1928. The fresh water Mollusca of southeastern United States. Malacological Rev., Wisconsin. Part II. Pelecypoda. Part 2, Wise. Geol. 6:105-117. and Nat. Hist. Survey Bull., 70:495 pp. ___. 1974. Clams and mussels (Mollusca: Bivalvia). Britton, J. C., D. R. Coldiron, L. P. Evans, Jr., C. In Hart, C. W. and S. L. H. Fuller (eds.). Pollution Golightly, K. D. O'Kane, and J. R. TenEyck. 1979. Ecology of Freshwater Invertebrates. Academic Press, Reevaluation of the growth pattern in Corbicula New York, pp. 215-273. fluminea (Muller). In: Britton, Joseph C., (ed.), Proc. Haas, F. I 969a. Superfamilia Unionacea. In: Das First International Corbicula Symposium. Texas Tierreich. Berlin. Lief., 88:I-X, 1-663. Christian University Research Foundation, pp. ___. 1969b. Superfamily Unionacea. In: Moore, R. 177-192. C. (ed.). Treatise on Invertebrate Paleontology, Part Britton, J. C. and B. Morton. 1979. Corbicula in North N, Mollusca 6. Bivalvia 1, N411-N471. America: the evidence reviewed and evaluated. In: Heard, W. H. 1977. Reproduction of fingernail clams Britton, Joseph C., (ed.), Proc. First International (Sphaeriidae:Sphaerium and Musculium). Malacologia, Corbicula Symposium. Texas Christian University 16(2):421-455. Research Foundation, pp. 249-287. Heard, W. H. and R. H. Guckert. 1971. Are-evaluation Clarke, A. H., Jr. and C. O. Berg. 1959. The freshwater of the recent Unionacea (Pelecypoda) of North mussels of central New York. Cornell University Agr. America. Malacologia, 10(2):333-355. Expt. Sta., Mern., 367:1-79. Hobbs, H. H., III., James H. Thorp and Gilbert E. Clench, W. J. and R. D. Turner. 1956. Freshwater Anderson. 1976. The freshwater decapod crustaceans mollusks of Alabama, Georgia, and Florida from the (Palaemonidae, Cambaridae) of the Savannah River Escambia to the Suwannee River. Bull. Florida State Plant, South Carolina. National Environmental Mus., 1:97-239. Research Park, Savannah River Plant, 63 pp. Coldiron, D. R. 1975. Some aspects of the biology of the Howard, A. D. 1914. Some cases of narrowly restricted exotic mollusk Corbicula (Bivalvia: Corbiculidae). M. parasitism among commercial species of freshwater S. Thesis, Texas Christian University, Fort Worth, mussels. Trans. Amer. Fisheries Soc., 44(1):41-44. Texas. 92 pp. Johnson, R. I. 1947a. Lampsilis carrosa Say and Connor, C. H. 1909. Supplementary notes on the Lampsilis ochracea Say. ace. Papers Moll., Mus. breeding seasons of the Unionidae. Nautilus, Compo Zool., I: 145-156. 22(10):111-112. ___. 1947b. The authorship of Elliptio complanatus. Cvancara, A. M. 1963. Clines in three species of Nautilus, 62-36. Lampsilis (Pelecypoda: Unionidae). Malacologia, ___. 1970. The systematics and zoogeography of the 1:215-225. Unionidae (Mollusca:Bivalvia) of the southern Atlantic Dance, S. P. 1966. Shell Collecting, An Illustrated slope region. Bull. Mus. Compo Zool., 140(6):263-449. History. Univ. Calif. Press, Berkeley, Calif., 334 pp. ___. 1972. The Unionidae (Mollusca:Bivalvia) of Eng., L. L. 1977. Biology and population dynamics of peninsular Florida. Bull. Florida State Mus. BioI. Sci., the Asiatic clam, Corbicula manilensis (Philippi, 16(4):181-249+Errata. 1841), in the Delta-Mendota Canal, San Joaquin Kraemer, L. R. 1970. The mantle flap in three species of Valley, California. Doctoral Dissertation, Univ. Calif., Lampsilis (Pelecypoda: Unionidae). Malacologia, Davis, 175 pp. 10(1):225-282. Frierson, L. S. 1927. A classified and annotated check Langley, T. M. and W. L. Marter. 1973. The Savannah list of the North American naiades. Waco, Texas: River Plant Site. U. S. Atomic Energy Commission Baylor Univ. Press, p. I-Ill. Report DP-1323, 175 pp. Fuller, S. L. H. 1971. A brief field guide to the Lea, I. 1852. Descriptions of new species of the family fresh-water mussels (Mollusca:Bivalvia:Unionidae) of Unionidae. Trans. Amer. Philos. Soc. 10:253-294. the Savannah River system. Assoc. Southeastern Biol, Lefevre, G. and W. C Curtis. 1910. Reproduction and Bull., 18(4):137-146. parasitism in the Unionidae. J. Exp. Zool., ___. 1972. Elliptio marsupiobesa, a new fresh-water 9(1):79-115. mussel (Mollusca:Bivalvia:Unionacea) from the Cape ___. 1912. Studies on the reproduction and artificial Fear River, North Carolina. Proc. Acad. Nat. Sci., propagation of freshwater mussels. Bull. Bureau Philadelphia, 124(1):1-10. Fisheries, 30:105-201. 22 Matteson, M. P. 1948a. The taxonomic and distributional Patrick, R., J. Cairns and S. Roback. 1966. An history of the freshwater mussel Elliptio complanatus ecosystematic study of the fauna and flora of the (Dillwyn, 1817). Nautilus, 61:127-132; 62:13-17. Savannah River. Proc. Acad. Nat. Sci., Philadelphia, ___. 1948b. Life history of Elliptio complanatus 118:109-407. (Dillwyn, 1917). Amer. MidI. Nat., 40:690-723. Simpson, C. T. 1893. On the relationship and MacFarlane, R. W. 1976. Fish diversity in adjacent distribution of the North American Unionidae. Amer. ambient, thermal, and post-thermal freshwater Nat. 27:353-358. streams. In Esch, G. W. and R. W. McFarlane (eds.), ___. 1900. Synopsis of the Najades, or pearly Thermal Ecology II. ERDA Symposium Series, freshwater mussels. Proc. U. S. Nat. Mus., 268-271. 22:501-1044. Modell, H. 1942. Das Naturliche system der Najaden. I. Sinclair, R. M. 1971. Annotated bibliography on the Archiv fur Molluskenkunde, 74:161-191. exotic bivalve Corbicula in North America, 1900-1971. ___. 1949. Das naturliche system der Najaden. 2. Sterkiana, 43: I 1-18. Archiv fur Molluskenkunde, 78:28-48. Sinclair, R. M. and B. G. !som. 1963. Further studies on ___. 1964. Das naturliche system der Najaden. 3. the introduced clam Corbicula in Tennessee. Stream Archiv fur Molluskenkunde, 93:71-126 (see English Pollution Control Board, Tenn. Dept. Public Health, translation of part of this paper by D. H. Stansbery 75 pp. and U. Soehngen, 1964, Sterkiana, 14:1-18). Smrchek, J. C. 1971. Present status of Elliptio Morton, B. 1977a. The population dynamics of complanatus in Douglas Lake, Michigan. Sterkiana, Corbicula fiuminea (Bivalvia: Corbiculacea) in Plover 43:10. Cove Reservoir, Hong Kong. J. Zool., London, Tucker, M. E. 1927. Morphology of the glochidium and 181:21-42. juvenile of the mussel Anodonta imbecillis. Trans. ___. 1977b. The occurence of inflammatory Amer. Micros. Soc., 46:286-293. granulomas in the ctenidial marsupium of Corbicula ___. 1928. Studies on the life cycles of two species fluminea (Mollusca:Bivalvia): A consequence of larval of freshwater mussels belonging to the genus incubation. J. Invert. Path., 30(1):5-14. Anodonta. BioI. Bull., 54:117-172. Ortmann, A. E. 1909. The breeding season of Unionidae Vallentine, B. D. and D. H. Stansbery, 1971. An in Pennsylvania. Nautilus, 22:91-95, 99-103. introduction to the naiads of Lake Texoma region, ___. 1910. A new system of the Unionidae. Oklahoma, with notes on the Red River fauna Nautilus, 23: 114-120. (Mollusca: Unionidae). Sterkiana, 42:1-40. ___. 191 I. A monograph of the Najades of van der Schalie, H. 1970. Hermaphroditism among Pennsylvania. Parts I and 2. Mem. Carnegie Mus., North American freshwater mussels. Malacologia, 4:279-347. 10:93-112. ___. 1912. Notes upon the families and genera of ___, and A. van der Schalie. 1950. The mussels of the Najedes. Ann. Carnegie Mus., 8:222-365. the Mississippi River. Amer. MidI. Nat. 44:448-466. ___. 1919. A monograph on the naiades of Wiles, M. 1975. The glochidia of certain Unionidae Pennsylvania. Part 3. Systematic account of the (Mollusca) in Nova Scotia and their fish hosts. genera and species. Mem. Carnegie Mus., 8:1-384. Canadian J. Zool. 53:33-41. Owen, G. 1966. Feeding. In: Wilbur, K. M. and C. M. Yonge (eds.), Physiology of Mollusca. New York, Academic Press, pp. I-51.

23 GLOSSARY anal aperture - The dorsal posterior excurrent mantle which include any lateral, pseudocardinal, or cardinal opening or siphon through which water and feces exit dentition and the interdentum. the mantle cavity. inflation - The lateral thickness of a bivalve. See Figure ungulate - Having the tendency to form an angle, in 2, page 83. contrast to being smoothly rounded. interdentum - The space on the hinge plate between arcuate - Curved or bent as in the shape of a bow. cardinal or pseudocardinal dentition and the lateral beak - The umbo, or oldest portion of a bivalve shell. teeth. Located on the dorsal surface, the beaks are lamellate (lamellar) - Formed in thin sheets or plates. frequently elevated above the surrounding shell laminate - Formed of thin sheets or plates lying one material. upon another. biangulate - Composed of two angular components. lanceolate - Elongate, lance-shaped. bifid - Having two parts; usually applied to the lateral teeth - Elongate tooth-like lamellae on the description of hinge teeth. posterior half of the hinge plate in Unionacea, or bradytictic - Referring to freshwater mussels which anterior and posterior to the cardinal teeth in other retain ova and/or glochidia in gill marsupia for very groups. long periods, usually during all seasons except left valve - The shell half on the left side of the body summer. when the shell is placed with the hinge up and the branchial aperture - The ventral posterior incurrent anterior end directed away from the observer. opening or siphon through which water enters the length - The maximum anteroposterior dimension. See mantle cavity. Water and pseudofeces can exit the Figure 4, page 83. mantle cavity through this aperture as a result of brief length/height ratio - The shell length divided by shell forceful contractions of various musculature. height. See Figure 4, page 83. cardinal teeth - Short, elevated triangular or slightly ligament - The elastic organic structure which joins the elongate toothlike lamella on the hinge plate two valves of a bivalve mollusk along the dorsal immediately ventral to the umbo. surface. caruncle - A small fleshy protuberance on the inner edge mantle - An epithelial extension of the dorsal body wall of each side of the mantle, directly anterior to the of mollusks which usually secretes the shell and branchial opening. Characteristic of members of the encloses a mantle cavity. genus Carunculina. marsupium - The pouch or brood chamber that contains clam - A common popular term for various members of ova, developmental stages, or larvae. In bivalves, the the molluscan class Bivalvia. The term is not gills can serve as marsupia. The location and size of restricted to any particular group of bivalves, except the marsupia are often useful taxonomic by colloquial usage. characteristics. crenulate - With a wrinkled or minutely toothed margin. mussels - A common name of two general categories of dendritic - Finger-like branching. bivalve mollusks, I) members of the Unionacea, demibraneh - One half of a gill of a bivalve mollusk. which are most often freshwater bivalves; or 2) Bivalves possess one pair of gills. Each gill is reflected members of the Mytilidae, which have numerous or folded upon itself; in cross-section it would appear brackish water or marine representatives. much like the letter W. A demibranch is one V of the nacre - The white, pearly, or iridescent inner shell layer W. Upon dissection, bivalves appear to have two gills of bivalves. It may be variably colored in some on each side of the body. Actually, these are two bivalves. demibranchs of the same gill. naiad - A general term applying to the freshwater edentulous - Lacking hinge teeth, as in Anodonta. mussels of the Superfamily Unionacea. elongate - The length dimension is noticeably greater obovate - Somewhat oval in outline, but one end than the height. narrower than the other. globose - Tending toward a spherical shape. opisthodetic - The condition in bivalve mollusks in glochidium - The characteristic bivalved parasitic larval which the hinge ligament is posterior to the umbo. stage of the Unionacea. pallial line - An impressed line on the bivalve shell gravid - When said of bivalves which brood larvae in gill interior locating the position of attachment of mantle marsupia, this term refers to the fact that the gills musculature. contain eggs, developmental stages, or larvae. papillate (papillose) - Having numerous finger-like height - The distance between dorsal and ventral projections or papillae. margins of the shell. See Figure 4, page 83. parvivincular - Ligament with long axis parallel to hinge height/inflation ratio - The height divided by inflation. line and lying posterior. hinge plate - The opposing dorsal portions of the valves pe divelig er - A form of shelled molluscan veliger larvae 24 which is adapted primarily for crawling rather than ray - A streak or linearly pigmented area usually swimming. associated with the periostracum. It may be periostracum - The organic covering on the exterior of interrupted or continuous. bivalve shells. right valve - The valve opposite the left valve, see latter. plication - A fold or costa involving a major portion of sinuate - To bend up and down or in and out. the shell thickness. subovate - A shape approximating an oval, but slightly posterior ridge - An external, slightly to sharply angulate to moderately produced or elongated in at least one ridge on the posterior portion of many bivalve shells direction. extending from the umbo to the ventral margin. When suhtrigonal - Transitional between trigonal and ovate: or the ridge is not easily differentiated by an angulation inequilaterally trigonal. on the shell, its location may often be determined by a tachytictic - Bivalve mollusks which brood larvae in distinct change in external sculpture. marsupia for relatively brief periods of time (i.e., posterior slope - The area of a bivalve shell dorsal and usually during spring and/or summer months only). posterior to the posterior ridge. trigonal - Shaped as a triangle; three cornered; usually prosogyrate - The beaks of the umbo point anteriorly. equilateral. protandry - A hermaphroditic condition whereby the tuberculate - Describing the presence of tubercules, male gonad develops first, degenerates, and is pustules or small globular surface irregularities followed by the development of the female gonads. especially on the exterior of a bivalve shell. pseudocardinal teeth - In Unionacea bivalves, these truncate - Cut-off, abbreviated, more-or-Iess squarely structures lie on the hinge plate near or anterior to the shortened. umbo. They are compressed, often triangular or umbo - The oldest part of the bivalve shell, the beak. slightly elongate dentition that have embryonic See latter. affinities closest to anterior lateral dentition, but lie in valve - One of two opposing halves of the shell of a the position normally occupied by cardinal teeth. bivalve mollusk, which lie on the lateral surfaces of Unionaceans lack true cardinal dentition. the body and are joined by a ligament.

25 ILLUSTRATIONS I. Elliptio complanata, right valve exterior. 2. Elliptio complanuta, dorsal aspect with posterior end toward top of page. Solid bar across valves indicates location where inflation (I) is measured. 3. Elliptio comp/anata, left valve interior. 4. villose vibex, left valve exterior. Solid bars indicate locations where length (L) and height (H) were measured for this study: note that the position of measurement is not necessarily the position of greatest shell height (see "height" in Glossary). 5. Schematic representation of dendritic branchial papillae, as expressed in Uniomerus tetralasmus. 6. Posterior mantle margins of three lampsiline genera. a. Lampsilis. Note flap-like lobe ventral to branchial aperture (BA) and prominent eyespot (E). b. Carunculina, Note caruncle (C) (i.e., mass of tissue) below branchial aperture (BA). c. Villosa . Legend: A, anterior end; AA, anterior adductor muscle scar; AN, anal aperture; BA, branchial (incurrent) aperture; D, dorsal margin; E, eyespot; H, height; I, inflation; ID, interdentum; L, length; LG, ligament; LT, lateral teeth; P, posterior end; PA, posterior adductor muscle scar; PL, pallial line; PR, posterior ridge; PS, pseudocardinal teeth; D, umbo or beak; V, ventral margin.

26 .'. ... 5 . ' .. .

-~ 'P' ., '\ ./ ) , -:-- ) l \ .> ~ <-> H ---- 4

LT o 10 LG

p A

3 v

27 PLATE I Figure I. Elliptio complanata, male, Collected June 10, 1977, Pen Branch Creek at Highway C Bridge, SRP, Figure 2. Elliptio icterina, male. Collected June I, 1977, Mill Creek, SRP. Figure 3. Elliptio congaraca. male. Collected June II, 1977, on sand bar of Savannah River approximately 2 km upstream from Johnson's Landing. Figure 4. Elliptio lancrolata, male. Collected June 2, 1977, Tinker Creek at Highway 8-11 crossing, SRP. Figure 5. Anodonta cataracta, Collected June 15, 1977, Lower Three Runs Creek near Donora Station, SRP. Figure 6. Uniomerus tetralasmus, female. Collected June 14, 1977, Lower Three Runs Creek near Donora Station, SRP. Figure 7. Anodonta imbecillis. Collected June 9, 1977, Par Pond, SRP, water depth approximately 8 m. Figure 8. Anodonta imbecillis. Collected June 9, 1977, Par Pond, SRP, water depth less than J m.

28 5

~~~- - .~ , ,""'"

7

29 PLATE II Figure I. Alasmidonta triangulata. Collected June 11, 1977, on sand bar of Savannah River approximately 6 km upstream from Johnson's Landing. Figure 2. Villosa vibex, female. Collected June 6, 1977, Reedy Branch Creek near Road 8-1, SRP. Figure 3. Villosa delumbis, female. Collected June 27, 1977, Tinker Creek just downstream from Kennedy Pond, SRP. Figure 4. Villosa delumbis, male. Collected June IS, 1977, Lower Three Runs Creek about y, km downstream from Donora Station, SRP. Figure 5. Lampsilis cariosa, male. Collected June 21, 1977, on sand bar of Savannah River approximately 6 km upstream from Johnson's Landing. Figure 6. Lampsilis cariosa, female. Collected July 20, 1977, on sand bar of Savannah River approximately 2 km upstream from Johnson's Landing. Figure 7. Lampsilis radiata splendida, male. Collected June IS, 1977, Lower Three Runs Creek about V3 km downstream from Donora Station, SRP. Figure 8. Corbicula j1uminea. Collected June 3, 1977, Savannah River, mile 157, shore of midchannel island, SRP.

30 ... MAP LEGENDS Map I. The Savannah River Plant showing major drainage systems and sampling locations. • Bivalve mollusks collected at these locations; '" Bivalve mollusks not collected or observed at these locations. THE FOLLOWING ARE ACADEMY OF NATURAL SCIENCES AT PHILADELPHIA COLLECTING LOCALITIES WHERE ADDITIONAL BIVALVE MATERIAL HAS BEEN COLLECTED.

1 On Upper Three Runs about \.i! mi below SRP Road A, where Elliptio icterina has been collected.

2 On the Savannah River, where Elliptio congaraca. E. icterina, E. complunata. E. lanceolata, Uniomerus tetralasmus, Anodonta imbecillis, A. cataracta, Vi/losa delumbis, Lampsilis curiosa, and Corbicula flumineu have been collected.

3 On the Savannah River, where all species collected at Station 2 were also collected, plus Alasmidonta ttiangulata. Andonta couperiana, and Strophitus undulatus,

4 On the Savannah River, where all species collected at Station 3 except Strophitus undulatus were collected, plus Carunculina pulla and Elliptio fraterna .

BB On the Savannah River, where Elliptio icterina and Lampsilis radiata splendida were collected.

D Donora Station, where Elliptio icterina. E. complanata, E. lanccotata, Uniomerus tetralasmus, Anodonta couperiana, Villosa delumbis, and Lampsilis curiosa were collected.

L3R On Lower Three Runs Creek at SRP Road A, where Eltiptio icterina, E. lanceolata, Anodonta cataractu and Villosa vibex were collected.

TeR On Lower Three Runs Creek at Tabernacle Road, where Elliptio icterina, E. lanceolata and Vil/osa vibex were collected. THE FOLLOWING MAPS INDICATE THE LOCATION OF BIVALVES COLLECTED DURING THE SUMMER, 1977.

Map 2. Collecting localities for Elliptio icterina, Anodonta cataracta, and Corbicula fiuminea, Map 3. Collecting localities for Elliptic camp/ana/a, Elliptic congaraea, and Anodonta imbecillis, Map 4. Collecting localities for Uniomerus tetralasmus, Lampsilis cariosa, and Alasmidonta triangulata. Map 5. Collecting localities for Elliptio lanceolata . Lampsilis radiata splendida, Vil/osa vibex, and V. delumbis.

32 .."Vl..... N

0, ,, ! I Iki lometers

o I I ! I- miles

33 ..'\..'\.... N

GEORG IA

• --EllilZ.tio icterino • Anodonla coloracla o • Corbicllia fillmineo I !,, , I kilometers o I ,I miles

34 N

GEORGIA

• ----£//il!.f/o comp/anofa E//iptio congaraea • o Anodonfa imbeci//us I',, , I • kilometers o , 1 miles

35 N

) .. C., ?

GEORGIA

• Uniomerus letraloslTlus .. Lamp-sills cariosa o • AlaslTI/donfa tasaostst« I !,, , I ki lometers o I !, miles

36 N

:~~ ; ...... ' .. 1 ,..0 ~e.,' . .: ;{ ~.,.~ IS' e; ',c-;.~ , c;. / .. 7::: Or" '; \ '=' .,J" :.f//;'·~C"'\tt . c-/-' "O"o/. . .$ ~ , ' "r./ eCo Ar--/ " G) S' ".. ,' .,', .: ,.~./ SOUTH : ,,~ GEORG IA 41,,, ' ,'. \ ,.c: ...... 1\' '," CAROLINA· I- ~~ j • E/liptio !anc8o!afo ~/'vl:~ r: ..{" • Lomp..si!is radio/a §12!endida r... y' ",0"" • Vi!!osa de!umbis and 0 '.,'(': I ! I! , I V. vibex kilometers: o ,, I miles

37 NOTES NOTES NOTES