''Smalleyus'' is a genus of

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s in the family

Pseudothelphusidae Pseudothelphusidae is a family of freshwater crabs found chiefly in mountain streams in the Neotropics. They are believed to have originated in the Greater Antilles and then crossed to Central America via a Pliocene land bridge. Parasitology Pse ...

, containing the single species ''Smalleyus tricristatus''. ''Smalleyus tricristatus'' was described by Fernando Alvarez in 1989, based on specimens collected in the

Los Tuxtlas Los Tuxtlas is a region in the south of the Mexican state of Veracruz. Politically it refers to four municipalities: Catemaco, San Andrés Tuxtla, Santiago Tuxtla and Hueyapan de Ocampo. It also refers to a high complex natural ecosystem, an isola ...

region of

Veracruz Veracruz (), formally Veracruz de Ignacio de la Llave (), officially the Free and Sovereign State of Veracruz de Ignacio de la Llave ( es, Estado Libre y Soberano de Veracruz de Ignacio de la Llave), is one of the 31 states which, along with Me ...

, adjacent to the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

(). ''Smalleyus tricristatus'' is listed as

Data Deficient A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...

on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

References

Pseudothelphusidae Freshwater crustaceans of North America Endemic crustaceans of Mexico Monotypic decapod genera Endemic fauna of Los Tuxtlas {{Crab-stub