Resumo

ALVAREZ, Fernando; VILLALOBOS, José Luis; ARMENDARIZ, Gema  e  HERNANDEZ, Carmen. Biogeographic relationship of freshwater crabs and crayfish along the Mexican transition zone: reevaluating Rodríguez (1986) hypothesis. Rev. Mex. Biodiv. [online]. 2012, vol.83, n.4, pp.1073-1083. ISSN 2007-8706.  https://doi.org/10.7550/rmb.28230.

After Rodríguez (1986) hypothesis on the possible biogeographic exclusion between crayfish of the family Cambaridae and freshwater crabs of the family Pseudothelphusidae throughout central and southern Mexico, several studies have considered it as a real pattern. However, the distribution patterns of both groups have not been examined, nor in what areas and to what extent the overlap of the 2 distributions occurs. Two data bases were compiled, one with more than 1 400 records of the species of the family Cambaridae and a second one with more than 400 records of freshwater crabs of the family Pseudothelphusidae. The resulting distribution maps show 3 areas where the contact is evident: the neovolcanic axis, Los Tuxtlas region, Veracruz, and the state of Chiapas. The results show large areas of contact in which both, crayfishes and crabs, can occur in the same locality and in the same body of water, or cases in which they occur in 2 nearby localities with an altitudinal difference. In general crayfishes tend to be distributed at higher altitudes than crabs. Together with the distribution patterns we discuss that the particular microhabitat of each group within the body of water prevents any interference or direct competition.

Palavras-chave : crayfish; Cambaridae; freshwater crab; Pseudothelphusidae; biogeographic exclusion.