Chevalia anomala, 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 : 27-31

Chevalia anomala sp. nov.

( Figs 1–3 )

Material Examined. Holotype, hermaphrodite, 3.0 mm (dissected and drawn), Bacia de Campos, 21º42’41” S – 40º10’52” W, February 1992, 86 m, supply boat N/RB Astro Garoupa col., MZUSP 22285. Paratypes. 10 unsexed specimens, Bacia de Campos, 21º42’41”S – 40º10’52” W, February 1992, 86 m, supply boat N/RB Astro Garoupa col., MZUSP 22286.

Etymology. This name refers to the anomalous condition of gnathopods 2 of the holotype with propodus of different lengths.

Description. Based on holotype, hermaphrodite (3.0 mm), MZUSP 22285. Eyes of large size, entirely situated in lateral lobe of the head, proximal margin of lateral cephalic lobe rounded. Antennae poorly setose. Antenna 1 1.8 X longer than of head and first four pereon segments combined; article 3 0.8 X longer than article 1, primary flagellum with 6 articles; flagellum accessory 2–articulate, article 1 shorter than article 2, 1/7 article 2 length. Antenna 2 shorter than antenna 1, article 4, article 4 as long as article 5, flagellum with 5 articles. Mandible palp 2.5 X longer than body of mandible, article 1 shorter, articles 2 and 3 subequal in length; incisor and lacinia mobilis with 5 and 2 teeth respectively, accessory setal row with 3 setae, molar process triturative. Lower lip, inner lobes and outer lobes separated, inner lobes large and fleshy. Maxilla 1 inner plate with apical setules; outer plate with 9 robust setae; palp 2–articulated with 3 apical robust setae and 2 subapical setae. Maxilla 2 outer plate slightly longer than inner plate, with oblique facial row of setae on inner margin; outer plate with a row of setae on apical margin, outer margin with a row of setules. Maxilliped inner plate rectangular with distal plumose setae; outer plate reaching to 1/3 of length of palp article 2, with 4 robust setae and 5 simple setae along medial margin and apically with 1 long plumose setae; palp, article 2 longer than articles 3 and 4 combined (1.4 X), article 4 with 1 long distal robust setae.

Coxae 1 and 2 larger than coxae 3–7, coxa 1 anteroventral angle rounded and slightly produced forward, coxa 2 anteroventral angle acute and strongly produced. Gnathopod 1 slender; carpus and propodus subequal in length, both articles with row of simple and plumose setae along posterior margin, palm oblique; dactylus with a small seta on inner distal margin. Gnathopod 2 coxal gill short, 1/ 2 x of basis length, basis stout, length 1.7 X width; right gnathopod with propodus longer than carpus and left gnathopod with propodus subequal in length to carpus; palm nearly transverse, defined by acute spine, inner margin sinusoidal and serrate; dactylus as long as palm, inner margin with a weakly rounded process near hinge of propodus. Three pairs of oostegites present, oostegite of pereopod 3 much reduced. Pereopods 3 and 4 scarcely setose; merus elongate, anterodistal corner weakly lobed. Pereopods 5–7 similar in shape, ratio length 0.6:0.7:1.0. Pereopod 5 basis ovate, length 1.25 X width, anterodistal margin with two setae; merus 1.2 X of carpus length, with antero and posterodistal angles slightly produced; carpus reniform, with posterodistal corner produced, with 2 submarginal robust setae; propodus length 2.3 X width; dactylus with 1 large accessory spine. Pereopod 6 basis ovate, length 1.7 X width, posterior margin with 3 setae; merus 1.3 X of carpus length, with anterodistal and posterodistal angles not produced; carpus reniform, with posterodistal corner rounded produced, with 1 submarginal robust seta and 1 simple setae; propodus length 3.85 X width; dactylus with 1 large accessory spine. Pereopod 7 basis ovate, length 2 X width, anterior margin with 1 seta; merus 1.65 X of carpus length, with anterodistal and posterodistal angles slightly produced; carpus reniform, with 3 submarginal setae on posterodistal corner; propodus length 4 X width; dactylus with 1 large accessory spine.

Posterodorsal margins of pleon 1–3 with a pair of long simple setae. Epimera 1–3, margin posterior slightly sinuose, posteroventral corner rounded, with a notch; epimeron 1 with 1 seta on notch. Uropod 1 peduncle subequal in length to outer ramus; inner ramus 1.1 X longer than outer ramus, inner margin with 10 large medial serrate spines, extending on almost half length of medial margin; outer ramus with all outer margin and sub apical inner margin with lateral setules, apical margin with 3 robust setae. Uropod 2 peduncle shorter than rami, with 1 seta on outer margin; inner ramus longer than outer, naked; outer ramus without marginal simple seta on outer margin, apical margin with 3 spines and 3 robust setae. Uropod 3, peduncle subequal in length to rami with 1 long plumose seta on outer margin; rami with apical plumose setae, outer ramus with apical robust seta. Telson distal margin with middle acute process and long plumose setae.

Remarks. Chevalia anomala sp. nov. belongs to group III of Chevalia , with ovate basis of pereopod 7. Nevertheless, it can be distinguished within the group by mandible palp short; gnathopod 2 coxal gill short male, palm defined by acute projection and dactylus the same length of palm; oostegite of pereopod 3 very reduced; epimera 1–3 with a notch on posteroventral corner; uropod 1 inner ramus with 9 serrate spines, extending on almost half length of medial margin.

The holotype has different morphological form of the second gnathopods: the right one with the larger propodus and the left one with small propodus, probably regenerant. This condition also had been observed by Barnard & Thomas (1987) in holotype female of the C. carpenteri , which appointed the condition abnormally stunted in this regenerating gnathopod.

Geographic distribution. Known only from type locality, Campos Basin, 21º42’41”S – 40º10’52”W

Depth range. Specimens were collected in 86 m.

Figures

FIGURE 1. Chevalia anomala sp. nov., holotype, hermaphrodite, (3.0 mm), Bacia de Campos, MZUSP 22285. Scale bars 0.1 mm.

FIGURE 2. Chevalia anomala sp. nov., holotype, hermaphrodite, (3.0 mm), Bacia de Campos, MZUSP 22285. Scale bars 0.1 mm.

FIGURE 3. Chevalia anomala sp. nov., holotype, hermaphrodite, (3.0 mm), Bacia de Campos, MZUSP 22285. Scale bars 0.1 mm.