New extension range of the porcelain crabs Pachycheles laevidactylus Ortman and new localities for P.chubutensis Boschi in marine waters of Argentina, Southwestern Atlantic Ocean. (Crustacea, Decapoda, Anomura, Porcellanidae)

SCELZO, MARCELO A; NAHUEL FARÍAS; EMILIANO OCAMPO; JESÚS D. NÚÑEZ; MAXIMILIANO CLEDÓN

Gramados. RS, Brasil

Congreso; V Congresso Brasileiro sobre Crustáceos.; 2008

Two porcelain crabs: Pachycheles laevidactylus Rodrigues da Costa, and P.chubutensis Boschi, are found in marine waters of Argentina from intertidal up to 30 m. Geographical distribution of P. laevidactylus includes: littoral marine waters of southwestern Brazil, Uruguay to Monte Hermoso, Buenos Aires province, Argentina. P. chubutensis was described for Chubut reaching Monte Hermoso, Argentina and their presence was also mentioned for Uruguay and southern Brazil. P.laevidactylus is an abundant intertidal rocky susbrate in Mar del Plata, building galleries in the mussel beds of the mytilid Brachidontes rodriguezi. Captures of crabs by means of diving confirm also the presence of P.chubutensis in Mar del Plata at depths between 3 - 10 m depths but both species never were captured together in the same habitat. In north patagonian waters of Las Grutas and San Antonio Oeste, Rio Negro province, both species were found living simultaneously in the intertidal rocky substrates. In both localities the individuals were adult specimens of both sexes. This study confirm the first finding of P.chubutensis living subtidaly in front of Mar del Plata (38º S) and extend the actual distributional range to the south of the species P.laevidactylus reaching San Antonio Oeste (40º S), Argentina. Both species are representatives of the fauna belonging to the temperate waters of the biogeographical Argentinean province. In this study it is enhance the morphological differences between the species