Valettiopsis ruffoi, Serejo & Wakabara, 2003

Serejo, Cristiana S. & Wakabara, Yoko, 2003, The genus Valettiopsis (Crustacea, Gammaridea, Lysianassoidea) from the southwestern Atlantic, collected by the RV Marion Dufresne, Zoosystema 25 (2), pp. 187-196 : 190-194

Valettiopsis ruffoi n. sp.

( Figs 2-4 )

TYPE MATERIAL. — Holotype: TAAF MD55 / Brazil 1987, Marion Dufresne, stn 45 CB 79 , 19°01’S,

37°47’W, 1500-1575 m, 28.V. 1987, 25 mm ( MNRJ 15697 ) ; paratype: stn 45 CB 79 , 1 25.3 mm ( MNRJ 15698 ) .

ETYMOLOGY. — This species is dedicated to the Italian amphipodologist Sandro Ruffo, for his friendship and tireless work on amphipods.

DIAGNOSIS. — Cephalic lobe rounded. Pereon segments 5-7 and pleon segments 1-3 smooth. Urosomite 1 with

a small dorsal tooth. Gnathopods 1-2,carpus longer than propodus; palm strongly oblique and dentate; dactylus with a long antero-distal setae. Coxa 4 deeply excavate posteriorly. Outer ramus of uropod 3 with distal article about 1/13 of proximal article. Telson cleft to about 6/7 of its length.

DESCRIPTION

Female (25 mm). Lateral cephalic lobe rounded, eyes lacking ( Fig. 2A, B ). Antenna 1, with callynophore; flagellum with 30+ articles; accessory flagellum with 5 articles. Upper lip rounded and apically setose ( Fig. 2C ). Lower lip ( Fig. 2D ), outer lobe elongate, with facial and distal setae; mandibular lobe well developed. Mandible ( Fig. 2E, F ), incisor toothed; molar triturative; left lacinia mobilis large, with many teeth. Maxilla 1 ( Fig. 2G, H ), inner plate densely setose; outer plate with 11 spines at distal end; distal margin of palp article 2 with stout short spines and a row of submarginal setae. Maxilla 2, inner and outer plates densely setose; inner plate with row of facial setae. Maxilliped ( Fig. 3A ), inner plate with 3 short and stout apical spines; outer plate inner margin with a row of short and stout spines, longer spines apically; palp articles 2-3 with long facial and distal setae, article 4 with long distal setae.

Coxa 1 short and triangular, distal margin with small setae ( Fig. 3B ). Coxa 2 rectangular, postero-distal margin with 4 setae ( Fig. 3D ). Coxa 3 rectangular. Coxa 4 deeply excavate posteriorly ( Fig. 2A ). Gnathopod 1 ( Fig. 3B, C ), basis anterior margin with sparse setae, posterior margin with a group of medial setae; merus, carpus and propodus densely setose posteriorly; carpus 1/4 longer than propodus; palm strongly oblique and dentate; dactylus fitting palm, bearing a long antero-distal seta. Gnathopod 2 ( Fig. 3D, E ), basis with sparse setae; carpus 1/3 longer than propodus; carpus and propodus bearing several rows of long setae and two sequences of tiny setae posteriorly; palm strongly oblique, dentate; dactylus with a proximal and a long antero-distal seta, not fitting palm. Basis of pereopod 7 lobate posteriorly ( Fig. 4A ). Epimera 2-3 produced. Urosomite 1 with a small dorsal tooth ( Fig. 2A ). Uropod 1 ( Fig. 4B ), peduncle with a disto-lateral process tipped with a stout spine; rami as long as peduncle. Uropod 2 ( Fig. 4C ), inner ramus longer than peduncle; outer ramus broken. Uropod 3 ( Fig. 4D ), inner ramus slightly shorter than outer ramus, with 6 proximal plumose setae on proximal inner margin; outer ramus twice the length of peduncle, distal article about 1/13 of proximal article. Telson ( Fig. 4E ) deeply cleft to about 6/7 of its length.

Male (25.3 mm): antenna 1 with callynophores, longer than that of female; accessory flagellum with 7 articles ( Fig. 2B ).

, V. dentata Holmes, 1908 ;, V. macrodactyla Chevreux, 1909 ;

REMARKS

Valettiopsis ruffoi n. sp. is similar to V. dentata in having slender gnathopods 1-2 with the carpus distinctly longer than propodus. However, V. ruffoi n. sp. can be distinguished from V. dentata and the other species of the genus, V. macrodactyla and V. multidentata , by the strongly oblique palm on gnathopods 1-2, which are nearly transverse in the other species; coxa 4 deeply excavated posteriorly; pereopod 7 basis lobate postero-distally, not tapering; reduced tooth on urosomite 1; and outer ramus of uropod 3 with distal article very short, about 1/13 of proximal article.

DISTRIBUTIONAL NOTES

Knowledge of the geographical distribution of Valettiopsis ( Fig. 5 ) is poor, because the species are found mostly in moderate to great ocean depths and have been captured only rarely. Two species have been recorded in the Atlantic Ocean: V. macrodactyla and V. ruffoi n. sp. This paper represents the first record of the genus Valletiopsis for the South Atlantic. Valettiopsis macrodactyla was known previously from the Azores (38°17’40”N) ( Chevreux 1909, 1935) and from the Bay of Biscay (about 47°20’N) ( Lincoln & Thurston 1983) and has its distribution extended to the southwestern Atlantic. Valettiopsis ruffoi n. sp. is known only from the type locality (19°01’S, 37°47’W, 1500- 1575 m). In the Pacific Ocean, V. multidentata has been recorded only from the type locality, Kermadec Trench (36°38’S, 178°21’E) ( Barnard 1961). Valettiopsis dentata has been recorded from off southern California ( Holmes 1908; Hurley 1963 [Coronado Canyon]; Barnard 1967).

Figures

FIG. 2. — Valettiopsis ruffoi n. sp.; A, habitus; B, head with peduncles of antennae 1-2; C, upper lip; D, lower lip; E, right mandible; F, incisor and lacinia mobilis of left mandible; G, H, maxilla 1; A, C-H, holotype, 25 mm (MNRJ 15697); B, paratype, 25.3 mm (MNRJ 15698). Scale bars: A, C-E, G, 0.5 mm; B, 1.0 mm; F, 0.2 mm; H, 0.1 mm.

FIG. 3. — Valettiopsis ruffoi n. sp.; A, maxilliped; B, gnathopod 1; C, palm of gnathopod 1; D, gnathopod 2; E, palm of gnathopod 2; A, D, E, holotype, 25 mm (MNRJ 15697); B, C, paratype, 25.3 mm (MNRJ 15698). Scale bars: A, B, 0.5 mm; C, E, 0.2 mm; D, 1.0 mm.

FIG. 4. — Valettiopsis ruffoi n. sp., holotype, 25 mm (MNRJ 15697); A, pereopod 7; B, uropod 1; C, uropod 2; D, uropod 3; E, telson. Scale bars: A, 1.0 mm; B-E, 0.5 mm.

FIG. 5. — Distribution of the genus Valettiopsis Holmes, 1908;, V. multidentata Barnard, 1961;, V. ruffoi n. sp.