Astrosansonia, Renard & Bouchet, 2003

Renard, Jacques Le & Bouchet, Philippe, 2003, New species and genera of the family Pickworthiidae (Mollusca, Caenogastropoda), Zoosystema 25 (4), pp. 569-591 : 571

Genus Astrosansonia n. gen.

“ Astrosansonia ” – Bouchet 1987: figs 141, 142. — Preece 1995: 352. — Bouchet & Le Renard 1998: 740, 741, fig. 15.101F, G. (In none of these cases, the genus name Astrosansonia has been made available [no type species designated, no diagnosis and/or published in a nomenclaturally unavailable work]).

TYPE SPECIES. — Liotia dautzenbergi Bavay, 1917: 112 , 113, pl. 3 figs 6-8 ( Fig. 1 ).

ETYMOLOGY. — The name refers to the star-shaped contour of the base.

DESCRIPTION

Shell very small, Liotia -shaped, with planispirally coiled teleoconch. Protoconch mucronate, consisting of 2.5 whorls, protruding almost vertically above teleoconch. Teleoconch with two to three whorls, forming flat spire, with sharply keeled periphery. Shell with star-shaped contour in dorsal view, due to projecting spines of peripheral keel. Base with very broad, open umbilicus lined with elevated rim. Outer part of peristome very oblique, almost parallel to base; outer lip forming broad rim, with quadrate outline.

Radula

The radula of Astrosansonia dautzenbergi (Bavay, 1917) n. comb. ( Fig. 1A, B ) was extracted and mounted for SEM by A. Warén. It is of generalized taenioglossate type (Caenogastropoda). Its only significant feature is the central tooth, which differs from all known rissoacean central teeth (W. Ponder pers. comm.), and does not allow a conclusive allocation of Pickworthiidae to a superfamily.

REMARKS

Astrosansonia dautzenbergi n. comb. ( Fig. 1 ) is very closely related to A. micraster (Boettger, 1907) n. comb., from the Miocene of Kostej, Rumania. Their slight differences may reflect chronological separation.

In the original description of Liotia micraster, Boettger (1907) compared it with Liotia discoidea Reeve, 1843 , with which it shares a very depressed outline and crenulated periphery, as do all other species of Dentarene Iredale, 1929 or Pterarene Sakurai & Habe, 1977 . However, Dentarene and Pterarene belong to Vetigastropoda , and are not confamilial with Astrosansonia n. gen. Several other skeneiform taxa, such as Pseudoliotia Tate, 1898 (see, e.g., P. micans (A. Adams, 1850)) , resemble Astrosansonia n. gen. by their strongly oblique, double aperture. Within the family Pickworthiidae , the very flat discoidal outline is characteristic of Astrosansonia n. gen.

Figures

FIG. 1. — Astrosansonia dautzenbergi (Bavay,1917) n. comb.; A, B, radula;C-E, topotype from Raiatea I., Society Is, Polynesia (MNHN), diameter 1.1 mm; F, protoconch. Abbreviations:c, central tooth; l, lateral; m, marginals. Scale bars: A, 2 µm; B, 3 µm; F, 50 µm.