A Review of the Troglobitic Decapod Crustaceans of the Americas

Abstract

Eight families comprising 18 genera and 55 species and subspecies of troglobitic and anchialine decapod crustaceans are recorded from the Americas. The family Atyidae is represented by two genera: Palaemonias, with two species occurring in the United States, and Typhlatya, encompassing seven species found in the West Indies, Yucatán, and the Galapagos Islands. Among the six genera of the family Palaemonidae are the Mexican monotypic Bithynops in Chiapas, Creaseria in Yucatán, and Neopalaemon in Oaxaca; in addition, one species of the genus Macrobrachium occurs in Oaxaca, two species of the genus Palaemonetes frequent subterranean habitats in the United States, and six members of the genus Troglocubanus occur in Cuba, Jamaica, and San Luis Potosí, Mexico. Only one troglobitic species of the genus Alpheopsis, a member of the largely marine family Alpheidae, occurs in the area, that in Oaxaca, Mexico. Two genera of the also primarily marine family Hippolytidae, Barbouria and Calliasmata, are each represented by a single species occurring in anchialine habitats in the West Indies, the latter only in the Dominican Republic. Of the three endemic American groups, the Cambarinae comprises the largest number of troglobites: there are eight species of Cambarus, six species and subspecies of Orconectes, and 13 species and subspecies of Procambarus; the former two are confined to the United States and the latter is present also in Cuba and Mexico; the monotypic Troglocambarus is restricted to peninsular Florida. The other two endemic groups, the families Aeglidae and Pseudothelphusidae, are represented, respectively, by a single species of the genus Aegla occurring in Brazil and one of Potamocarcinus in Chiapas, Mexico. The remaining widespread family Grapsidae encompasses a member of the genus Sesarma in Jamaica. Following a presentation of the composition of the fauna and a historical account of investigations leading to our present knowledge of it is a discussion of the evolution of the several groups and a key to aid in the identification of members of the fauna. The systematic section includes synonymies for the genera, subgenera, species, and subspecies. Each of the supraspecific taxa is diagnosed, its range defined, and the numbers of species and troglobitic or anchialine representatives noted. For each species and subspecies, as complete a synonymy as we have been able to obtain is provided. Also a diagnosis, the maximum size, disposition of the types, type-locality, and range (including locality records) are followed by a summary of available ecological and life-history data; illustrations are provided for each. Appended to this study is a list of the non-troglobitic decapods that are known to occur in subterranean habitats, a glossary of terms employed in the text, and a list of the symbionts of American troglobitic decapods.