Six new species of the genus Chevalia Walker, 1904 (Amphipoda, Corophiidea, Chevaliidae) from Brazilian waters, with a key to world species of the genus Author Souza-Filho, Jesser F. Author Souza, Ana Maria T. Author Valério-Berardo, Maria Teresa text Zootaxa 2010 2713 25 51 journal article 10.5281/zenodo.199662 c9e923c4-f0c9-4bfe-9269-0ee2a6c04555 1175-5326 199662 Chevalia thomasi sp. nov. ( Figs 16–18 ) Material examined. Holotype , female, 5.1 mm , Baía de Todos os Santos, Bahia, #P3, 13º02.410’S 38º37.8’W , 16 m , col. O. Falcão, MNRJ 15794. Paratypes . 1 female (dissected and drawn), 5.3 mm , Revizee Central #17, 18°39.78’S 37°52.2’W , dredge, supply boat N/RB Astro Garoupa col., 29 November 2001 , 65 m, MNRJ 21958. 3 females, Revizee Central #17, 18°39.78’S 37°52.2’W , dredge, supply boat N/RB Astro Garoupa col., 29 June 2001 , 65 m, MNRJ 21956. 7 females, Revizee Central C6 R2 #1-1, 19°46.6’S 39°31.08’W , Box-corer, supply boat N/RB Astro Garoupa col., 15 June 2002 , 92 m, MNRJ 21957. 4 females, Revizee Central #Y7, 20°50.94’S 40°10.02’W , dredge, supply boat N/RB Astro Garoupa col., 77 m , 28 June 2002 , MNRJ 21954. 2 females, Revizee Central #25R, 19°31.62’S 38°46.08’W , dredge, supply boat N/RB Astro Garoupa col., 28 June 2002 , 65 m, MNRJ 21955. Etymology. Named in honor to Dr. James Darwin Thomas (Nova Southeastern University Oceanographic Center, Florida) for his contributions on amphipods taxonomy. Description. Based on holotype , female, 5.1 mm (MNRJ 15794) and paratype , female, 5.3 mm (MNRJ 21958). Eyes of large medium size, entirely situated in lateral lobe of the head, proximal margin of lateral cephalic lobe rounded . Antennae densely setose. Antenna 1 1.5 X longer than the length of head and first 4 pereon segments combined; peduncular article 3 0.6 X longer than article 1 , primary flagellum with 7 articles; flagellum accessory 3–articulate , article 1 shorter than article 2, article 3 rudimentary, 1/10 article 2 length. Antenna 2 as long as antenna 1 ; article 4 subequal in length to article 5; flagellum with 5 articles. Mandible palp 2 X longer than body of mandible , article 1 very shorter, articles 2 1.1 X longer than article 3; incisor and lacinia mobilis with 4 and 5 teeth respectively, accessory setal row with 5 setae, molar process triturative. Lower lip, inner lobes and outer lobes separated, inner lobes large and fleshy. Maxilla 1 inner plate with marginal setules; outer plate with 6 robust setae; palp 2–articulated with five apical robust setae and three subapical plumose setae. Maxilla 2 outer plate longer than inner plate, with oblique facial row of setae on outer margin; outer plate with a row of setae on apical margin. Maxilliped inner plate rectangular with distal margin with 4 robust setae and 4 plumose setae; outer plate reaching to 1/2 of length of palp article 2, with 4 robust setae and row of plumose setae on medial and facial margin and apically with 1 plumose and 1 robust setae; palp, article 2 longer than articles 3 and 4 combined (1.3 X), article 4 with 1 long distal robust seta. FIGURE 16. Chevalia thomasi sp. nov. , paratype female (5.4 mm), Revizee Central #17, MNRJ 21958. Scale bars 0.1 mm. Coxae 1 and 2 larger than coxae 3–7, both with anteroventral angle weakly produced . Gnathopod 1 slender; carpus 1.3 X longer than propodus, both articles with row of simple and plumose setae along posterior margin, palm oblique; dactylus naked. Gnathopod 2, coxal gill reaching about 2/3 of basis length; basis moderately slender, length 1.5 X width ; carpus subequal in length to propodus, not lobate; propodus posterior margin with a row of simple setae, palm transverse, with shallow “U”–excavation near hinge of dactylus , defined by weakly produced blunt process, dactylus shorter than palm, with a small acute projection near articulation of propodus . Three pairs of oostegites present . Pereopods 3 and 4 scarcely setose; merus elongate, anterodistal and posterodistal corners with a lobe weakly rounded. Pereopod 5 basis ovate, as long as width posterior margin with 4 setae; merus 1.5 X of carpus length, with antero and posterodistal angles produced; carpus reniform, with posterodistal corner rounded produced, with 1 submarginal robust seta and 1 simple seta; propodus length 2.2 X width; dactylus with 1 large accessory spine and 1 plumose seta. Pereopod 6 basis ovate, length 1.7 X width, posterior margin with 6 setae; merus 2.2 X of carpus length, with antero and posterodistal angles produced; carpus reniform, with posterodistal corner produced, with 1 submarginal robust seta and 1 seta; propodus length 4 X width; dactylus with 1 large accessory spine. Pereopod 7 basis rectangular, length 2.8 X width, posterior margin with 13 setae, posterodistal angle not produced ; merus 1.6 X of carpus length, with anterodistal angle produced; carpus reniform,, with 1 submarginal robust seta and 2 long setae; propodus length 4 X width; dactylus with 1 large accessory spine. FIGURE 17. Chevalia thomasi sp. nov. , paratype female (5.4 mm), Revizee Central #17, MNRJ 21958. Scale bars 0.1 mm. FIGURE 18. Chevalia thomasi sp. nov. , paratype female (5.4 mm), Revizee Central #17, MNRJ 21958. Scale bars 0.1 mm. Posterodorsal margins of pleon 1–3 and pleon 1–3 with a pair of long simple setae . Epimera 1–3, posteroventral margin slightly sinuose posteroventral corner rounded, without a notch . Uropod 1 peduncle subequal in length to inner ramus, with three setae on outer margin; inner ramus 1.2 X longer than outer ramus, with inner margin with 11 large proximomedial serrate spines ; outer ramus apical margin with five spines and three robust setae . Uropod 2 peduncle shorter than inner ramus, with 1 seta on outer margin; outer ramus shorter than inner ramus , apical margin with 6 spines and three robust setae , inner ramus naked. Uropod 3 peduncle shorter than rami; rami with apical plumose setae. Telson subquadrate, distal margin convex, with a rounded middle process; 2 rows lines of small spines and three distolateral plumose setae in each side. Remarks. Chevalia thomasi sp. nov. is similar to C. inaequalis , both included in the group II, by the pereopod 7 basis rectangular lacking produced posterodistal corner. But the new species is characterized by the diagnostic features of the accessory flagellum 3–articulate; carpus of gnathopod 2 as long as propodus; and the only 1 submarginal robust seta on posterodistal corner of pereopods 5–7. Geographic distribution. Bahia to Espírito Santo (18º– 20ºS) Depth range. 16 to 92 m depth.