CHAPTER XV MOLLUSKS Blank page retained for pagination MOLLUSKSl By HARALD A. REHDER, Smithsonian Institution 2 . The Gulf of Mexico is, chronologically speak­ Indian fauna but have also some affinities with Ing, probably the least known body of water those of the deeper waters off the southern ~djoining the United States, and the mollusks of Atlantic coast of the United States. Its shores are as yet only imperfectly known. This is particularly the case with the area between PAST WORK DONE IN THIS AREA Cedar Keys on the Florida coast, and Sabine Pass GENERAL on the Louisiana-Texas border, and with the part of the coast line stretching between the mouth of The first publication that·gave a list of the the Rio Grande and the vicinity ·of Veracruz. mollusks found along the entire Gulf coast and The littoral fauna of the Gulf of Mexico may discussed their geographical ranges was Dall's be divided into two elements that inhabit different (1889) catalog, reprinted, with additions, in geographical areas. There is first the tropical 1903. Dall divided the southeastern coast into 10 elelllent found on the Florida Keys and north on geographical districts. Three of these districts the Gulf side of Florida to about Tampa Bay, covered the area included in this report: Florida the northwest coast of Cuba, and the Mexican Keys, from the Keys north to Charlotte Harbor, coast from Cabo Catoche on Yucatan north to West Florida, from Charlotte Harbor to the t~e vicinity·of Corpus Christi, Texas (and pos­ Mississippi Delta, and the deeper waters of the SIbly to near Matagorda Bay). This area forms Gulf east of longitude 90°, and Texas, from the the southern limit of the Gulf of Mexico and is Mississippi Delta to the Rio Grande, and the deep t~e only part of the Gulf area in which living, waters south to Yucatan. The broad extent of the fringing reef corals are found. Joubin's (1912) Texas district has led to the inclusion, in later representation of coral reefs in Tampa Bay is lists, of many species as being found in Texas that obviously an error. have not as yet been recorded from the waters of North of this tropical Caribbean area the fauna that State. This is true, for instance,of Johnson's takes on a more temperate character, showing an (1934) list mentioned later. ob\Tious relationship with that of the zoogeo­ Maury (1920, 1922) published a catalog of the ~r~Phical province generally known as the Caro- recent mollusks of the Gulf of Mexico in which llian. The physiography of this area is also in were included some Tertiary species. Johnson's gheneral different from that of the more southerly (1934) List of the Marine Mollusca of the Atlantic S ores. It is a region characterized mainly by Coast from Labrador to Texas came out post­ sandy beaches either on the mainland or on low humously. This check list, though not always,· ~hastal or barrier islands that are separated from indicates those species found along the shores of e lllainland by shallow lagoons or bays with the Gulf of Mexico. tasses or inlets between the individual islands. FLORIDA t 0 coral reefs are found in this area, although fhere are submerged coral banks off the coast as The west coast of Florida is better known from a ar north as northern Florida. malacological standpoint than any other section of shThe lllollusks of the deeper waters of the Gulf the area under discussion. Numerous catalogs ow, lllainly, a relationship with the West and annotated lists covering this area were pub­ ------ lished in. the seventies and eighties: Calkins : iUbllshed by permission of the Secretary of the Smithsonian Institution (1878, 1880), Dall (1884), Simpson (1887, 1889). 'l'. ll: WOuld like to acknowledge the helpful suggestions received from Prof. Pulley of the University of Houston. Melvill (1881) gave a list of the mollusks of Key 469 470 FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE West, enumerating 123 species. In more recent scribed by R. A. Philippi. Singley (1893) gave years several papers have been published dealing an extensive list of the marine mollusks of the with the mollusks of Sanibel Island, near the Texas coast, listing 342 species. This contribu­ mouth of the Caloosahatchee River, in Lee tion, being based in part on Dall's (1889) cata­ County; Clench (1923, 1925) listed 89 species, logue, contained many species for which no records while Haas (1940) gave ecological notes on many from the waters of Texas proper are known. of the species found here. In the last few decades Mitchell (1894) published, privately, a list of some collecting has been done along the north­ Texas marine shells enumerating 81 species. The western coast (Lyman 1942; Schwengel and list was based on his own collecting and dealt McGinty 1942). The most complete work on the mainly with the mollusks of the Matagorda­ mollusks of western Florida is that by Louise Corpus Christi Bay area. Strecker's (1935) list Perry, Marine Shells of the Southwest Coast of of Texas marine shells appeared posthumously; it Florida, 1940, in which she describes 346 species contained 188 species, a number of which were most of which are illustrated. not in Singley's list. As an appendix Strecker gave a list of 176 species said by Dall to come from the ALABAMA-LOUISIANA Texas district but for which Strecker had no spe­ The published records for this area are cific localities. Stenzel (1940) published a list of fewer than for the Gulf coast of Florida or for 56 species from Point Isabel, Texas. A consider­ Texas. The first faunal list I have been able to able amount of ecologic!},l work is being carried on find is that by Vanatta (1904) who published a at the present time by workers at the Institute of list of mollusks from Horn Island, Mississippi. Marine Science at Aransas Pass (Hedgpeth, 1950; Cary (1906) enumerated 73 species from various Whitten et aI., 1950) as well as at the laboratory places along the Louisiana coast from Cameron of the Texas Game, and Fish Commission at in the western part to the Chandeleur Islands in Rockport. Recently, Pulley (1949 and 1952) pub­ the east. Whereas in Cary's list the proportion of lished on the mollusks of the Texas coast. His gastropods to pelecypods is 32 to 38, in the Horn 1952 pap('r is a comprehensive one, in which he Island list the proportion is 3 to 32. This seems has included, with appropriate comments, those to suggest that the shells of Horn Island were species previously l'l'corcled from Texas, but not gathered almost exclusively along the outer known to occur thcI'l'. beach and that further search on the lagoon side MEXICO of the island would bring to light further species. In 1929, Clench listed 23 species from various Onlv a few papers have been published on the molhl~ks ~1exico. localities in southern Louisiana in the Missis­ of the cast coast of Baker Si~a~~ sippi Delta region. Burkenroad (19a3) enu­ (1891) listed 216 spccies from Veracruz, merated 9 species of pteropods from the waters of Pl'Ogrpso, ano Campcche (the last three locahtlc Louisiana. The most recent list of Louisiana shells a1'p on the peninsula of Yucatan), and Hinkley (Harry 1942) gives 93 species from the vicinity of (1907) enumerated 47 marine shells from the Grand Isle and Barataria Bay. This report, the vicinity of Tampico. result of 12 years collecting by members of the CUBA staff of the Louisiana State University ~farille '1'lw oldl'r works on Cuban shells, such as those Laboratory staff there, shows how impoverished by d'Orbigny llnd Arango, gavc no speellC'fi local­ the fauna is in this part of the Gulf in comparison it'ies for tIll' 'rnnrinl' mollusks. In the Cutll1ogo de with that of the regions farther south on both los :\lo1uscos de Cub']" Aguayo and ,Tuume (1947­ . .' 1 ,thwcst sides of the Gulf. 52) pubhslll'(1 some records from t w nOl 1- Coll- TEXAS coust of CubIt. Henderson's (1916) I)00 ~ tains also a gooll Ilict l1I'P of (hl' nortll\\'(,s(el'lll Tlw first enumeration of the mollusks of this ,, . f 010 - purt of the Gulf, and indeed of any purt of the coast of Cuha, nlthou~lI II(' ~ivps no lIst 0 " ,I url'a covered by this rrport, was that published lusks. Lit tIP colh'c( intr Sl'('IllS to Illtv!' been Cll1'lle< '" t I ('tweell by Frrdinand Roemer in his work on Tl'xas out nl()])lT thl' Plll't of till' Cuban COI1S ) I t "" I (' 1 . \. l'p<Tion t lit (Ropmrl' 1849). Out of 54 SIWci('s lip listl'd fl'om HIIt )nllll HI)( .1l)O :-ian i ntonLO, It '" tht' island of Gnln'ston 7 WPJ'(' lll'\\' spl'ci('s clo- should 1)(' v('r} rich ill mollusks. GULF OF MEXICO 471 DEEPER WATERS Mexico from Cabo Catoche to the vicinity of Port The first work on the fauna of the deeper waters Isabel, Texas, and possibly beyond to Corpus of the Gulf of Mexico was carried out in 1878 by Christi Bay. the United States Coast Survey steamer Blake As is to be expected, the mollusks of this area under the direction of Professor Alexander Agas­ show an obvious relationship with those of the siz. The mollusks gathered during this cruise West Indies and the entire Caribbean region. Were reported on by Dall (1886-89). Subse­ The list of species has of necessity been taken quently, the steamer Albatross of the United largely from our knowledge of the Floridian mol­ States Fish Commission made numerous stations luscan fauna.