Endothyrella williamsoni (Gude, 1915)

Pall-Gergely, Barna, Budha, Prem B., Naggs, Fred, Backeljau, Thierry & Asami, Takahiro, 2015, Review of the genus Endothyrella Zilch, 1960 with description of five new species (Gastropoda, Pulmonata, Plectopylidae), ZooKeys 529, pp. 1-70 : 43-45

Taxon classification Animalia Pulmonata Plectopylidae

Endothyrella williamsoni (Gude, 1915) Figure 17A

Endothyrella williamsoni 1915 Plectopylis (Endothyra) williamsoni Gude: Records of the Indian Museum, 8: 509, Plate 42, figs 1 a–d. ["Abor Hills, exact part not indicated"].

Types.

Abor Hills, leg. C.F.G. Oakes, R.E., NHMUK 1903.7.1.3087. (5 syntypes, Figure 17A)

Diagnosis.

Shell very small, sinistral with narrow umbilicus and conical dorsal surface; shell hairless but densely, finely ribbed and ornamented with low radial periostracal lamellae on the whole shell; callus strong; palatal plicae horizontal, almost straight and thin at their middle; lamella slightly curved; there is long, horizontal plica anteriorly to the lamella, and a short horizontal plica above the long one; additionally, there is a very short upper plica above the lamella, a small denticle posteriorly above, and a long lower plica near the suture which reaches the aperture.

Measurements

(in mm): D: 6, H: 3.6-3.7 (n = 2, type series).

Differential diagnosis.

Endothyrella williamsoni has a more elevated spire than Endothyrella macromphalus and Endothyrella minor , and has two horizontal parietal plicae anterior to the lamella which are missing in the other two species. The most similar species in terms of shell shape and size to Endothyrella williamsoni is Endothyrella blanda . The latter species, on the other hand, lacks the two horizontal parietal plicae anterior to the lamella which area characteristic for Endothyrella williamsoni . Moreover, Endothyrella blanda specimens have seven rows of hairs, whereas Endothyrella williamsoni is hairless. Endothyrella robustistriata sp. n. is smaller, has stronger dorsal sculpture and lack the main plica which is characteristic for Endothyrella williamsoni . See also Table 5.

Distribution.

This species is known from the type locality only (Figure 10).