Talassia rugosa, Hoffman & Freiwald, 2022

Hoffman, Leon & Freiwald, André, 2022, A review of Atlantic deep-water species in the genus Talassia (Caenogastropoda, Vanikoridae), European Journal of Taxonomy 819, pp. 140-157 : 153-154

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scientific name

Talassia rugosa

sp. nov.

Talassia rugosa sp. nov.


Figs 51–56 View Figs 51–56


The specific epithet refers to the rugose axial and spiral sculpture.

Type material

Holotype ANGOLA – Castle Mounds • 1 shell ( Figs 51–54 View Figs 51–56 ); 9.6650° S, 12.7156° E; depth 453 m; 1 Jan. 2016; van Veen grab; in fine sand with clay; M122-GeoB20958 ; SMF358973 View Materials . GoogleMaps

Paratypes ANGOLA – Castle Mounds • 1 shell ( Figs 55–56 View Figs 51–56 ); same collection data as for holotype; SMF358974 View Materials GoogleMaps 2 shells; same collection data as for holotype; SMF358975 View Materials GoogleMaps 2 shells; same collection data as for holotype; Naturalis, Leiden, the Netherlands GoogleMaps .


Elevated shell with rounded whorls and flattened apex, irregular axial sculpture of raised ribs and spiral cordlets, flexuous lip and smooth protoconch, cream white. Holotype dimensions: height 3.2 mm, width 1.6 mm, apical angle 36°.

PROTOCONCH. Flattened paucispiral shell with 1¼ whorls ( Figs 52–53, 56 View Figs 51–56 ); smooth; lip straight ( Fig. 56 View Figs 51–56 ); width 0.34 mm.

TELEOCONCH. Elevated spire with 4 rounded whorls and deep suture ( Figs 51, 55 View Figs 51–56 ). Axial sculpture with irregularly spaced slightly flexuous ribs and numerous growth lines. Irregularly-spaced spiral cordlets composed of sets of closely-aligned lines of various strength; lines composed of raised dots ( Fig. 54 View Figs 51–56 ). Umbilicus nearly completely covered by columellar lip ( Fig. 51, 55 View Figs 51–56 ).

APERTURE. Oval outline, slightly concave on parietal side; smooth inside ( Figs 51, 55 View Figs 51–56 ). Columellar lip sharp; external lip not thickened, blunt, flexuous with notches above periphery and at base. Aperture height 1.1 mm in holotype.

VARIABILITY. Little variability observed. Observed adult height 3.0– 3.2 mm.


The species is only known from the type locality.


The radula and the soft parts of the new species are unknown.

Differential diagnosis

Talassia dagueneti has a similar teleoconch sculpture but its axial sculpture is more regular and lacks the spiral cordlets and its protoconch has a stronger spiral sculpture and a more elevated outline ( Warén & Bouchet 1988; Figs 4–7 View Figs 1–11 ) whereas T. rugosa sp. nov. has a more conical outline, an irregular sculpture with spiral cordlets and a smooth protoconch with a flattened outline. Talassia mexicana sp. nov. from the Gulf of Mexico is larger and it has a more regular and stronger axial sculpture.