Epitonium tumidulum
(Thiele, 1930)
Description:
Dimensions range from 1.9 mm - 1.9 mm high and 1.3 mm wide.
Width to height ratio: 0.68:1 ~ 0.68:1
Shell: turbinate, broad conical; thin; microscopic. Exterior colour colourless. About 6 whorls, convex, rapidly expanding, body whorl about 2/3 of the shell height; relatively large; protoconch with ~3 whorls smooth; teleoconch with ~3 whorls rapidly increasing, strongly convex whorls. Imperforate. Costae are dense, low, thin. Intercostal spaces close, with fine spiral threads. Base without a cord. Columella broad, somewhat concave. Aperture oval; outer lip incomplete.
Ponder [1978:437] comments the unique specimen is a juvenile shell of uncertain species relationship. Weil et al. [1999:132] comment that the illustration by Ponder [1978:437] may prove just to be a juvenile E irregulare (Sowerby II, 1844)
Distribution:
NW Western Australia [Ponder, 1978:437]
Habitat:
3m, sand with vegetation [Ponder, 1978:437], 3m, sand
Etymology:
[latin] from tumidulus, the diminutive form of tumidus = somewhat swollen, puffed up
Type Material:
Holotype: West Australian Museum reg. no. 67496 for Epitonium tumidulum (Thiele, 1930) - Type Locality: Station 3, ca 5 km NW of Denham, Sharks (= Shark) Bay, north-west Australia, 3 m, sand with rich vegetation (holotype) (reg. no. 67496). [Ponder, W. F., 1978]
Ponder, W. F. (1978). pp: 438. Fig. 1.
Holotype reg. no. 67496
Distribution
as listed in source literature
Ponder, W. F. (1978).
pp: 438. Fig. 1.
Holotype reg. no. 67496
