Chevalia convexa, 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 : 35-38

Chevalia convexa sp. nov.

( Figs 7–9 )

Material examined. Holotype, hermaphrodite, 3.2 mm, Revizee NE-III #59, off Rio Grande do Norte State, 2°48’S 39º 28.8ºW, 16 May 1998, 22 m, N/Oc. Antares col., MNRJ 21967. Paratypes. 14 females Revizee NE-III #59, off Rio Grande do Norte State, 2°48’S 39º 28.8ºW, 16 May 1998, 22 m, N/Oc. Antares col., MNRJ 14393. 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 21952. 1 female, 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 21953. 10 females, Revizee NE #59, off Rio Grande do Norte State, 2°48’S 39º 28.8ºW, 16 May 1998, 22 m, N/Oc. Antares col., DOUFPE 14391. 1 hermaphrodite and 2 females, Revizee NE #59, off Rio Grande do Norte State, 2°48’S 39º 28.8ºW, 16 May 1998, 22 m, N/Oc. Antares col., DOUFPE 14392. 16 females, Revizee NE-IV #165, 8º 8.1ºS 34º38.1’W, 0 1 December 2000, 40 m, N/Oc. Antares col., DOUFPE 14394. 2 females, Revizee NE #59, off Rio Grande do Norte State, 2°48’S 39º 28.8ºW, 16 May 1998, 22 m, N/Oc. Antares col., DOUFPE 14.396. 20 females, Revizee NE-III #59, off Rio Grande do Norte State, 2°48’S 39º 28.8ºW, 16 May 1998, 22 m, N/Oc. Antares col., DOUFPE 14395. 1 female, 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 21968. 19 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 21969. 4 females, Revizee Central #35C, 20º52’S 40º10’W, dredge, supply boat N/RB Astro Garoupa col., 55 m, 20 July 2001, MNRJ 21970. 2 females, Revizee Central #25, 19°31.62’S 38°46.08’W, dredge, supply boat N/RB Astro Garoupa col., 28 June 2001, 65m, MNRJ 21971. 13 females, Revizee Central #5, 15°34.08’S 38°49.8’W, dredge, supply boat N/RB Astro Garoupa col., 0 1 July 2001, 20 m, MNRJ 17765. 3 females, Revizee NE #59, off Rio Grande do Norte State, 2°48’S 39º 28.8ºW, 16 May 1998, 22 m, N/Oc. Antares col., MNRJ 21972. 22 females, Revizee Central #1R1, 21°38.94’S 40°10.8’W, dredge, supply boat N/RB Astro Garoupa col., 13 July 2001, 140 m, MNRJ 21973. 2 females, Revizee Central #24, 20°20.82’S 36°38.52’W, dredge, supply boat N/RB Astro Garoupa col., 13 July 2001, 55 m. MNRJ 21974. 2 females, Revizee Central #36C, 21°30’S 40°18’W, dredge, supply boat N/RB Astro Garoupa col., 21 June 2001, 52 m, MNRJ 21975. 3 females, Revizee Central #44L, 20°51.42’S 33°21.78’W, dredge, supply boat N/RB Astro Garoupa col., 11 July 2001, 65 m, MNRJ 21976. 139 females, Baía de Todos os Santos, Bahia, #P2, 13°05.519’S 38°39.837’W, van Veen grab, 5 March 1997, 12 m, col. O. Falcão, MNRJ 15788. 12 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 17771. 4 females, Bacia do Ceará, Espada CON PEP- 1, 3°9.28’S 38°46.13’W, June 2003, without collector information, MNRJ 19641.

Etymology. The specific name convexa (Latin) , meaning convex, refers to distal margin of telson.

Description. Based on holotype, hermaphrodite (3.2 mm), MNRJ 21967. Eyes of medium size, partially situated in lateral lobe of the head, proximal margin of lateral cephalic lobe straight. Antenna 1 slightly longer than head and first four pereon segments combined; peduncular article 3 0.75 X longer than article 1; primary flagellum with 5 articles; flagellum accessory 3–articulate, article 1 shorter than article 2, article 3 rudimentary, 1/5 of article 2 length. Antenna 2 as long as antenna 1, article 4 1.2 X longer than article 5; flagellum with 6 articles. Mandible palp 2 X longer than body of mandible, article 1 shorter, articles 2 and 3 subequal in length; incisor and lacinia mobilis with 3 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 row of setae; outer plate with 8 robust setae; palp 2–articulated with 4 apical robust setae and 1 subapical seta. Maxilla 2 outer plate longer and slightly broader than inner plate, both plates apically setose, inner plate with oblique facial row of setae. Maxilliped inner plate rectangular; outer plate reaching to half of length of palp article 2, with 5 robust setae along medial margin and apically with 1 long plumose setae; palp, article 2 longer than articles 3 and 4 combined (1.2 X), article 4 with 1 long distal robust setae.

Coxae 1 and 2 larger than coxae 3–7, both with anteroventral angle strongly produced. Gnathopod 1 slender; carpus and propodus subequal in length, both articles with row of setae along posterior margin, palm oblique and minute serrate; dactylus with 1 small seta on inner distal margin. Gnathopod 2 coxal gill reaching about 1/2 of basis length; basis stout, length 1.8 X width; carpus weakly lobed, anterior margin longer than posterior margin (5 X); propodus massive, 1.6 X of carpus length; posterior margin with 4 tuft of setae and subparallel to anterior margin; palm transverse, defined by 1 acute spine, inner margin sinusoidal and serrate; dactylus as long as palm, inner margin with a weakly developed process near hinge of propodus and with 6 simple setae. Three pairs of oostegites present, first one weakly developed compared with the others. Pereopods 3 and 4 similar in shape, scarcely setose; merus elongate and slightly inflated, anterodistal corner weakly lobed. Pereopods 5–7 similar in shape, ratio length 0.8:10:1. Pereopod 5 basis ovate, length 1.25 X width, posterior margin with 2 setae; merus 1.35 X of carpus length, with antero and posterodistal angles produced; carpus reniform, with posterodistal corner produced, with 2 submarginal robust setae and one long seta; propodus length 2.2 X width; dactylus with 1 large accessory spine. Pereopod 6 basis ovate, length 1.3 X width, posterior margin with 6 setae; merus 1.75 X of carpus length, with antero and posterodistal angles produced; carpus reniform, with posterodistal corner produced, with 2 submarginal robust setae and 2 long setae; propodus length 2.85 X width; dactylus with 1 large accessory spine. Pereopod 7 basis ovate, not produced on posteroventral angle, length 1.65 X width, posterior margin with 4 setae; merus 1.45 X of carpus length, with antero and posterodistal angles produced; carpus reniform, with posterodistal corner produced, with 2 submarginal robust setae and one long seta; propodus length 2.85 X width; dactylus with 1 large accessory spine.

Posterodorsal margins of pereon 6–7 and pleon 1–3 with a pair of long simple setae. Epimera 1–3, posteroventral margin rounded, with a notch, each notch with a seta. Uropod 1 peduncle subequal in length to outer ramus, with 4 setae on outer margin; inner ramus 1.2 X longer than outer ramus, with inner margin with 13 large medial serrate spines, outer ramus medial and apical margins with row of setules, apical margin with 5 spines and 2 robust setae. Uropod 2 peduncle shorter than rami, with 3 long setae on outer margin; rami subequal in length, outer ramus without marginal simple seta on outer margin, apical margin with 4 spines and 3 robust setae; inner ramus naked. Uropod 3 peduncle shorter than rami with 2 long plumose setae on outer margin; rami with apical plumose setae. Telson subquadrate, distal margin convex, with lines of long simple setae on dorsum and 1 distolateral plumose setae in each side, distal margin convex and lacking middle process.

Remarks. Chevalia convexa sp. nov. can be separated from those species within group III of Chevalia by the following combination of states of characters: antenna 1 slightly longer than head and first four pereon segments combined; mandible palp twice longer than body of mandible; gnathopod 2 anteroventral angle of coxa 2 acute and moderately produced, coxal gill reaching about 1/2 of basis, palm transverse and defined by a acute spine; 3 oostegites present; dorsal margins of pereon 6–7 and pleon 1–3 with a pair of long simple setae; posterior margin of epimeron 1–3 rounded with a notch and a seta; and telson with distal margin convex and lacking middle process.

Geographic distribution. Ceará, Rio Grande do Norte, Pernambuco and Bahia (2°48’S to 21°38’S).

Depth range. 12 to 140 m.

Figures

FIGURE 7. Chevalia convexa sp. nov., holotype, hermaphrodite (3.2 mm), Revizee NE-III # 59, off Rio Grande do Norte State, MNRJ 21967. Scale bars 0.1 mm.

FIGURE 8. Chevalia convexa sp. nov., holotype, hermaphrodite (3.2 mm), Revizee NE-III # 59, off Rio Grande do Norte State, MNRJ 21967. Scale bars 0.1 mm.

FIGURE 9. Chevalia convexa sp. nov., holotype, hermaphrodite (3.2 mm), Revizee NE-III # 59, off Rio Grande do Norte State, MNRJ 21967. Scale bars 0.1 mm.