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The Origins and Affinities of the Troglobitic Crayfishes of North America (Decapoda, Astacidae). I. The Genus Cambarus

1960; University of Notre Dame; Volume: 64; Issue: 1 Linguagem: Inglês

10.2307/2422890

1938-4238

Horton H. Hobbs, Thomas C. Barr,

Fish Biology and Ecology Studies

One of the most interesting phases of the history of crayfish dispersal and modification is that associated with the origins of troglobites. There are a few generalizations which can be drawn concerning the distributions and the origins of the several stocks which have engendered populations that have been able to meet the demands of a subterranean existence. In order to gain the proper perspective of the distributional relationships of the cavernicolous crayfishes with their epigean relatives, a brief summary of the distributions of the four genera with hypogean representatives is presented. The largest genus in the family Astacidae, Procambarus, comprises more than 100 species and subspecies of which six are true troglobites. The range of the genus extends from Cuba, Guatemala and Honduras northward to Illinois and southern New England. Most of the species are found in the southeastern parts of the United States and Mexico where they are confined largely to the Coastal Plain and Piedmont Provinces. Only in Mexico have representatives been able to cross the divide into the Pacific drainage. The six albinistic species and subspecies are known only from Florida (4), Veracruz, Mexico (1), and Pinar del Rio, Cuba (1); that from the latter has not been described. The monotypic genus Troglocambarus is known only from caves in the Florida peninsula. The genus Orconectes, the second largest in the family, is composed of approximately 60 species and subspecies, and among them five troglobitic taxa have been recognized. The range of this genus is largely confined to the Mississippi and Great Lakes drainage systems, but a few species have reached the extreme southeastern part of the United States, and two occur east of the Appalachian system in an area extending from Maine to Virginia. The hypogean representatives are found in the Interior Low Plateaus of southern Indiana, central Kentucky and Tennessee, and northern Alabama. The genus Cambarus, comprising some 40 species and subspecies, is represented by six troglobitic species within the United States. Its range extends from the Gulf of Mexico (Texas to northern Florida) to Canada; however, most of the species occur in the eastern part of the United States, along the slopes of and in streams arising in the Appalachian Mountains. The present discussion concerns the cavernicoles of this genus.