Trivellona enricoschwabei, Fehse & Grego, 2012

Trivellona enricoschwabei spec. nov.

Figs 9-12 View Figs 9- 12

Trivellona schepmani (Schilder, 1941) – Fehse & Grego 2004, 2009: pl. 3, figs 14-16.

Types. Holotype: ZSM 20110214 , 26°15'N 124°42'E, off Xiamen ( prov. Fujinan), near Chilwei Island , E China Sea; trawled at 360 m depth GoogleMaps . – Paratypes: Nos. 1-2: “Stat. 95, 5°43.5'N., 119°40'E, Sulu Sea, 522 M, Stony bottom” ( Schepman 1909: 140), ZMA 03.09.027 ; GoogleMaps No. 3: “ East of Sailus-Besar, Paternoster Islands , Netherlands East Indies; in up to 36 metres of water; coral and Lithothamnion bottom” ( Schepman 1909: 140), ZMA 03.09.28 ; Nos. 4-5: Off Xiamen, near Chilwei Island , E China Sea; trawled at 100-130 m; Nos. 6-8: Off Xiamen, near Chilwei Island , E China Sea; dredged at 170 m on gravel and sand; Nos. 9-13: Off Xiamen, near Chilwei Island , E China Sea; trawled at 360 m. All material comprises empty shells from type locality that were obtained from different reliable sources.

Description

Shell small sized (see Table 2 View Table 2 ), lightweight, somewhat fragile, globose. Spire covered by terminal ribs. Body whorl somewhat semi-circular, globose, rounded, approximately 90 % of total shell height; anterior terminal produced, tip blunt; posterior terminal slightly so. Dorsum evenly rounded, not much elevated, completely covered with coarse, close-set ribs. Ventrum convex, with terminal collars straight. Aperture narrow, curved especially towards the canals. Labrum narrow, straight at its mid-portion, curved anteriorly and posteriorly, roundly keeled on ventrum, bearing on its inner margin denticles.Outer labral margin slightly roundly callused. Siphonal and anal canals following shell profile; bordered adapically and abapically by weak ventral side walls. Columella narrow, straight, tapering steeply inwards, without a carinal ridge. Parietal lip roundly callused, slightly projected, bearing ribs, which become finer onto the columella.Fossula short, concave, not clearly delimited from the rest of the columella. Inner fossular edge slightly protruding.

Shell colour overall white.

No information available on soft parts and radula.

Variation. The length varies between 5.6 and 7.7 mm (see Table 2 View Table 2 ). The posterior terminal is more or less produced. The terminal collars can be slightly recurved. The number of dorsal ribs varies between 18 and 26, of labral denticles between 17 and 21, of parietal ribs between 14 and 18, and of terminal ribs that cover the spire between 2 and 3.

Etymology. The name of the species honours Mr. Enrico Schwabe from ZSM.

Distribution. From Chilwei Island, E China Sea ( type locality) in the north to the Sulu Sea, Philippines and Java Sea in the south in depths between 100 and 360 m on gravel and sand ( Fig. 8 View Fig ).