Dolichupis pingius, Simone & Cunha, 2012

Simone, Luiz Ricardo L. & Cunha, Carlo M., 2012, Taxonomic study on the molluscs collected in Marion-Dufresne expedition (MD 55) to SE Brazil: Xenophoridae, Cypraeoidea, mitriforms and Terebridae (Caenogastropoda), Zoosystema 34 (4), pp. 745-781 : 756-758

Dolichupis pingius n. sp.

( Fig. 4 E-H)

TYPE MATERIAL. — Holotype: Brazil, Espírito Santo, off Regência, continental slope of Abrolhos , 19°40’S, 37°48’W, 790-940 m depth, MNHN 25222 ( Fig. 4 E- G) ( MD55 , stn CB77 , Bouchet, Leal & Métivier coll., 27.V.1987).

Paratypes: same data as holotype, MZSP 104030, 2 shells ( Fig. 4H ). — Off Itaúnas, 18°59’S, 37°48’W, 607-620 m depth, MNHN 25223, 2 shells (stn DC 73).

TYPE LOCALITY. — Brazil, Espírito Santo, off Regência, continental slope of Abrolhos, 19°40’S, 37°48’W, 790- 940 m depth ( MD 55, stn CB 77).

DISTRIBUTION. — Off Espirito Santo, Abrolhos continental slope.

ETYMOLOGY. — The specific epithet is derived from the word “pi’ngi” in the native Parintintin language, meaning few ( Betts 1981), an allusion to the low quantity of ribs of the shell.

DIAGNOSIS. — Shell of c. 5 mm, with outer lip highly expanded posteriorly; lacking dorsal groove; colour white. Sculpture c. 10 ribs, mostly continuous from side to side; c. 13 ribs in outer lip weakly protruding inside. Aperture in right side (far from central region).

DESCRIPTION

Shell of c. 5-6 mm; outline cuneiform, with outer lip expanded in upper, posterior region at right from apex; width c. 76% of length, height c. 65% of length. Colour pure white. Anterior and posterior canals similar from each other ( Fig. 4B, C ), weakly protruded, anterior canal extending less than 10% of shell length; posterior canal extending c. 20% of shell length, dislocated to right side ( Fig. 4E, G, H ). Spire entirely covered; apex not seen. Sculpture c. 10 narrow ribs, mostly perpendicular to longitudinal axis, weakly inclined to left ( Fig. 4E, H ); interspaces c. 3 times ribs width; practically all ribs running from side to side, entirely lacking dorsal groove; 1-2 ribs, mainly located in both, anterior and posterior regions, ending about half way between ventral region and median line ( Fig. 4E, F, H ); 4-5 ribs located on both canals positioned longitudinally, forming an angle of c. 30° in relation to remaining ribs ( Fig. 4E, H ), those more distant from median line touching with each other after distance c. 15% of shell length; middle longitudinal ribs simply ending. Aperture narrow, arched only in both ends, but more arched in anal canal ( Fig. 4G ); comprising c. 8% of shell width and c. 80% of shell length; located on right third. Outer lip thick, with c. 27% of shell width, anterior and posterior regions extending beyond spire, posterior end strongly more curved than anterior end ( Fig. 4G ); c. 14 transverse ribs, weakly protruding in inner edge, continuing as and similar to dorsal ribs; middle ribs perpendicular to longitudinal shell axis, gradually becoming oblique towards both canals. Siphonal and anal canals narrow, weakly turned dorsally; siphonal canal more straight and located closer to median line; anal canal weakly more right located, strongly turned to left and about 50% longer than siphonal canal ( Fig. 4G ). Inner lip lacking callus, fossular depression only in anterior third; c. 11 ribs weakly protruded inside aperture; c. 5 ribs in fossular depression somewhat narrower and more obliquely positioned in relation to remaining ribs, further possessing small node in innermost region ( Fig. 4G ). Ribs in ventral region at left from aperture similar and continuous to dorsal ribs.

MEASUREMENTS (inmm). — Holotype: 5.6 × 4.3; paratype MZSP 104030 : 6.2 × 4.9.

HABITAT. — Sandy-mud bottoms, 670-940 m depth.

DISCUSSION ON TRIVIIDS

Cleotrivia antillarum is the single triviid with dorsal groove, from those collected in MD55 expedition. The characteristic small size and the blunt anterior and posterior projections are the main feature for the identification. The southernmost record for the species was Rio Grande do Norte ( Rosenberg 2009), the present record expands about 1000 km southwards the species geographic distribution. The bathymetric distribution, however, changes little, as the species have been collected up to 525 m, and is here reported to 670 m.

The remaining two species,which are here described as new, Dolichupis akangus n. sp. and D. pingius n. sp. are easily distinguishable by entirely lacking dorsal furrow, bearing ribs continuous from one side to another on dorsal region. This, associated with the small size and deep-water occurrence, are the main reasons for considering them in the genus Dolichupis , although the generic distinction in the triviids are not always forthright ( Cate 1979; Fehse 2002; Fehse & Greco 2005). Dolichupis akangus n. sp. differs from D. pingius n. sp. mainly in having much more ribs (compare Figure 4A and E ), in being more rounded and in lacking the outer lip so expanded posteriorly; furthermore, D.akangus n. sp. lacks the differentiation of the sculpture on the fossular depression of the inner lip (compare Figure 4C and G ), which additionally possesses a shorter depression.The closest species from both Dolichupis here described is D. virgo Fehse & Greco, 2005 ; D. akangus n. sp. differs in being slightly more elongated, in having fewer ribs (c. 15 ribs, against 18-22 ribs of D. virgo ), and by total absence of dorsal furrow, which are mostly present in D. virgo ; D. pingius n. sp. differs mainly by the posterior expansion of the outer lip, in lacking dorsal furrow, and in bearing much fewer ribs (c. 10). Both new species are furthermore different from the Caribbean Cleotrivia candidula (Gaskoin, 1836) and C.leucosphaera (Schilder,1931) , which also lack dorsal furrow, in being slightly more elongated, in having fewer ribs (those species possess c. 25-30ribs), and by wider and more left-placed aperture. Both new species still differs from D. paucilirata (Sowerby, 1870) and from D. panamensis (Dall, 1902) ( Cate 1979; Fehse & Greco 2005) in being slightly larger, in having more ribs (those species have c. 8-10), and by wider and longer aperture.

Superfamily MURICOIDEA Rafinesque, 1815 Family COSTELLARIIDAE MacDonald, 1860

Figures

FIG. 4. — Triviids:A, Dolichupis akangus n. sp., holotype MNHN 25218, dorsal view (L 5.6 mm);B, same, right view;C, same,apertural view; D, paratype MNHN 25221, dorsal view (L 5.3 mm); E, D. pingius n. sp., holotype, MNHN 25222, dorsal view (L 5.6 mm);F, same, right view; G, same, apertural view; H, paratype MZSP 104030, dorsal view (L 6.2 mm).