Thysanota Albers 1860

Vermeulen, Jaap J., Liew, Thor-Seng & Schilthuizen, Menno, 2015, Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species, ZooKeys 531, pp. 1-139 : 60

Taxon classification Animalia Stylommatophora Endodontidae

Genus Thysanota Albers 1860

Nanina section Thysanota Albers in Albers & Von Martens, 1860: 63. Thysanota (Albers) Godwin Austen, 1907 (1897-1914): 189; Gude 1914: 10; Naggs and Raheem 1999: 23.

Queridomus Iredale, 1937: 322; Solem 1988: 552).

Diagnosis for the Sabah species.

Shell conical, with almost flat sides, with depressed whorls. Teleoconch: Radial sculpture prosocline, consisting of densely placed to moderately spaced, fine riblets. Last whorl with 2-3 distinct spiral threads (next to a number of much finer spiral threads), the lowermost around the periphery, the others above the periphery and often interrupted. Umbilicus open, narrow, or closed.

Cross diagnosis.

The Sabah species of Thysanota differ from Philalanka by the combination of a conical spire, with almost flat sides, somewhat depressed whorls and a very narrow, or closed umbilicus.

Remarks.

The generic position of the two species listed below is unresolved. Solem (1988: 552) places Thysanota grenvillei in the Helicarionidae , although he finds its anatomy different from other Australian helicarionid genera. Godwin Austen (1907 [1897-1914]: 189) dissects an Indian species, Thysanota carinigera (Benson), and places the genus in the Endodontidae . Solem also expresses the possibility that Thysanota conula (as Liardetia fimbriosa ), and Thysanota grenvillei belong to the same genus. With several more samples of both species at hand from widely scattered localities in S. and S.E. Asia, we conclude that their shells, at least, show striking similarity. The genus Thysanota includes more species with similar shells (see Gude 1914: 10; Naggs and Raheem 1999: 23); we feel that the species below are best placed in this genus.