Description of two new species of the Corophiidae (Amphipoda, Crustacea) and register of Laticorophium baconi (Shoemaker, 1934) from Brazilian waters Author Valério-Berardo, Maria Teresa Author Souza, Ana Maria Thiago De text Zootaxa 2009 2215 55 68 journal article 10.5281/zenodo.189937 83d33b93-cdbb-4784-b902-d8c718bb1dc5 1175-5326 189937 Monocorophium acherusicum (Costa, 1851) Figure 5 Material Examined: 1 male 3.5 mm , 23º53’ S e 46º 11’ W , intertidal, col. Umbuzeiro, G., 28/11/2008 , MZUSP 19617. Diagnosis : Rostrum of male minute, deeply recessed to lateral head lobes. Male antenna 1 peduncular article 1 with 1 distal robust seta on ventromedial margin. Female antenna 1 peduncular aticle 1 with 3–4 robust setae on dorsomedial margin and 4–5 robust setae on ventral margin. Male antenna 2 strongly pediform; peduncle article 4 with 1 long and 2 short acute process on vetrodistal corner, peduncle article 5 with distal process on ventral margin; flagellum short weakly setose. Female antenna 2 articles 3–5 with robust setae on ventromedial margin. Male gnathopod 2 dactylus with 2 teeth on flexor margin, unequal in length. Male pereopod 7 basis medium broad. Urosome segments fused. Uropod 1, peduncle with 2–4 robust setae on medial margin; uropod 2 rami with robust setae on apical margins; uropod 3 ramus rounded apically. Remarks: Monocorophium acherusicum has cosmopolitan distribution and it is perhaps the most widely distributed species of corophiin amphipod in temperate-tropical waters of the world ( Bousfield & Hoover, 1997 ). This species was recorded form Brazilian waters for Serejo, 1998 , that appointed some variations on numbers of robust setae of antennae peduncle, comparing the Brazilian specimens with descriptions of Chevreux & Fage, 1925 ; Bousfield, 1973 and Myers, 1982 . But this species is distinguished from the others of the genus by rostrum deeply recessed, gnathopod 2 with 2 teeth on flexor margin and uropod 1 peduncle with 2–4 robust setae on both medial margins.