Chevalia setosa, Souza-Filho, Jesser F., Souza, Ana Maria T. & Valério-Berardo, Maria Teresa, 2010

Souza-Filho, Jesser F., Souza, Ana Maria T. & Valério-Berardo, Maria Teresa, 2010, Six new species of the genus Chevalia Walker, 1904 (Amphipoda, Corophiidea, Chevaliidae) from Brazilian waters, with a key to world species of the genus, Zootaxa 2713, pp. 25-51 : 42-46

Chevalia setosa sp. nov.

( Figs 13–15 )

Material examined. Holotype, hermaphrodite, 4.1 mm, Rocas Atoll, Rio Grande do Norte, 3º51.680’S 33º49.604’W, 19 m, in sponges and algae, 16 October 2000, col. P.S. Young, P.C. Paiva, and A.A. Aguiar, MNRJ 21959. Paratype. 1 hermaphrodite, 3.6 mm, (dissected and drawn), Rocas Atoll, Rio Grande do Norte, 3º51.68’S 33º49.604’W, 19 m, in sponges and algae, 16 October 2000, col. P.S. Young, P.C. Paiva, and A.A. Aguiar, MNRJ 21960. 4 hermaphrodites, Rocas Atoll, Rio Grande do Norte, 3º51.68’S 33º49.604’W, 19 m, in sponges and algae, 16 October 2000, col. P.S. Young, P.C. Paiva, and A.A. Aguiar, MNRJ 21961. 1 hermaphrodite, Rocas Atoll, Rio Grande do Norte, Piscina das Tartarugas, 3°52.42’S 33°48.30’W, Rio Grande do Norte, 19 m, in Plakortis sp., November 1999, col. G. Neves, MNRJ 16617. 6 females and 4 hermaphrodites, Rocas Atoll, Rio Grande do Norte, 3º51.747’S 33º49.497’W, 14 m, 16 October 2000, col. P.S. Young, P.C. Paiva, and A.A. Aguiar, MNRJ 21962. 5 females, Rocas Atoll, Rio Grande do Norte, Salão, 3°52.46’S 33°48.43’W, intertidal, in sponges and algae, 13 October 2000, col. P.S. Young, P.C. Paiva, and A.A. Aguiar, MNRJ 21963. 5 hermaphrodites, Rocas Atoll, Rio Grande do Norte, Piscina das Tartarugas, 3°52.42’S 33°48.30’W, Rio Grande do Norte, 19 m, in sponges, 28 December 2000, col. F. Pitombo and R. Barros, MNRJ 21964.

Etymology. The Latin name setosus, hairy, referring to the densely setose dorsum, a characteristic unique within the genus.

Description. Based on holotype, hermaphrodite, (4.1 mm), MNRJ 21959, and paratype hermaphrodite (3.6 mm), MNRJ 21960. Eyes of large size, entirely situated in lateral lobe of the head, proximal margin of lateral cephalic lobe straight. Antennae setose. Antenna 1 1.2 X longer than head and first four pereon segments combined; peduncular article 3 0.70 X longer than article 1, primary flagellum with 8 articles; flagellum accessory three–articulate, article 1 shorter than article 2, article 3 rudimentary,1/11 of article 2 length. Antenna 2 slightly shorter than antenna 1, article 4 1.1 X longer than article 5, flagellum with 6 articles. Mandible palp 2 X longer than body of mandible, article 1 shorter, articles 2 slightly longer than article 3; incisor and lacinia mobilis with 4 teeth, accessory setal row with 4 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 8 robust setae; palp 2–articulated with 4 apical robust setae and 1 subapical plumose seta. Maxilla 2 outer plate slightly longer than inner plate, with apical plumose setae; outer plate with facial and apical setae. Maxilliped inner plate rectangular with distal margin with 4 robust setae and plumose setae; outer plate reaching to 1/2 of length of palp article 2, with 5 robust setae and 5 simple setae along medial and facial margin and apically with 1 long plumose setae; palp, article 2 longer than articles 3 and 4 combined (1.7 X), article 4 with 1 long distal robust setae.

Coxae 1 and 2 larger than coxae 3–7, coxa 1 anteroventral angle strongly produced forward, coxa 2 anteroventral strongly angle 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 short, 1/3 of basis length, basis stout, length 1.8 X width; carpus shorter than propodus, not lobate; propodus massive, 2 X of carpus length; posterior margin with tuft of short setae and parallel to anterior margin; palm transverse, defined by 1 acute spine, inner margin sinusoidal and serrate; dactylus shorter than palm, inner margin with a weakly developed process near hinge of dactylus. Three pairs of oostegites present, oostegite of pereopod 3 much reduced. Pereopods 3 and 4 scarcely setose; merus elongate, anterodistal corner with a lobe weakly rounded. Pereopods 5–7 similar in shape, ratio length 0.6:0.9:1.0. Pereopod 5 basis ovate, length 1.1 X width, posterior margin with three setae; merus as long as carpus length, with anterodistal corner produced; carpus reniform, with posterodistal corner slightly produced, with 2 submarginal robust setae and 1 long plumose seta; propodus length 2.3 X width; dactylus with 1 large accessory spine. Pereopod 6 basis ovate, length 1.3 X width, posterior margin with 6 setae; merus 1.3 X of carpus length, with anterodistal corner produced; carpus reniform, with posterodistal corner rounded produced, with 2 submarginal robust setae and 1 long seta; propodus length 2.85 X width; dactylus with 1 large accessory spine. Pereopod 7 basis ovate, length 1.9 X width, posterior margin with 5 setae; merus 1.45 X of carpus length, with anterodistal corner produced; carpus reniform, with posterodistal corner produced, with 2 submarginal robust setae and 1 long seta; propodus length 3.85 X width; dactylus with 1 large accessory spine.

Posterodorsal margins of pereon 1–7 and pleon 1–3 with a line of +10 long simple setae in adults, in subadults about 6 long simple setae. Epimera 1–3 posterior margin nearly straight, posteroventral angle rounded, without a notch, with setae. Uropod 1 peduncle subequal in length to outer ramus,; inner ramus 1.3 X longer than outer ramus, inner margin with 10 large medial serrate spines, outer ramus all inner and apical margin with row of setules, apical margin with three robust setae. Uropod 2 peduncle shorter than rami, with 2 setae on outer margin; inner ramus longer than outer, naked; outer ramus, with 4 apical robust setae, apical margin with 2 spines. Uropod 3, peduncle shorter than rami; rami with apical plumose setae, outer ramus with apical robust seta. Telson distal margin with convex middle process and long plumose setae.

Remarks. Chevalia setosa sp. nov. is readily distinguished from those of the other species of the group III by the diagnostic feature of long and numerous setae on posterodorsal margins of pereon 6 and 7.

Geographic distribution. Known only from type locality Rocas Atoll.

Depth range. Intertidal to 19 m.

Figures

FIGURE 13. Chevalia setosa sp. nov., HA: holotype, hermaphrodite (4.1 mm), Rocas Atoll, Rio Grande do Norte, MNRJ 21959. Mouthparts: paratype, hermaphrodite (3.6 mm), Rocas Atoll, Rio Grande do Norte, MNRJ 21960. Scale bars 0.1 mm.

FIGURE 14. Chevalia setosa sp. nov., paratype, hermaphrodite (3.6 mm), Rocas Atoll, Rio Grande do Norte, MNRJ 21960. Scale bars 0.1 mm.

FIGURE 15. Chevalia setosa sp. nov., Ep 1 - 3: holotype, hermaphrodite (4.1 mm), Rocas Atoll, Rio Grande do Norte, MNRJ 21959. Paratype, hermaphrodite (3.6 mm), Rocas Atoll, Rio Grande do Norte, MNRJ 21960. Scale bars 0.1 mm.