Revisiting the genus Bathyporeiapus Schellenberg, 1931 (Amphipoda: Exoedicerotidae), in the Temperate South America ecoregions

The genus Bathyporeiapus Schellenberg, 1931, includes three intertidal amphipod species present in the southern region of South America: Bathyporeiapus bisetosus Escofet, 1970, and B. ruffoi Escofet, 1971, in the Atlantic waters and B. magellanicus Schellenberg, 1931, in the Pacific. Bathyporeiapus taxonomy is understudied, with records mainly from general intertidal fauna inventories. In this context, the present study provides a redescription of B. magellanicus and B. ruffoi , with comments on morphology of B. bisetosus . The type material of B. magellanicus , B. bisetosus , and B. ruffoi was analyzed, and new specimens of B. bisetosus and B. ruffoi were collected in the intertidal zone of the São Paulo and Rio Grande do Sul state, southern Brazil. Species differ in the number of T-setae on peduncle article 3 of antenna 2: B. magellanicus (3), B. bisetosus (2), and B. ruffoi (4), and in the number of articles on pereopod 7 dactylus: B. bisetosus (5–8), B. magellanicus (8–10), and B. ruffoi (14); also, B. magellanicus presents maxilla 1 with setae on the inner plate. Furthermore, the males of Bathyporeiapus species are not known, and in the present study, more than a thousand female and juvenile individuals were collected, but not males, reinforcing the need for studies on life history. An identification key for the three known species of Bathyporeiapus is given.