Amaea thielei
(de Boury, 1913)
Description:
Dimensions range from 10 mm - 35 mm high and 6.33 mm - 7 mm wide.
Width to height ratio: 0.63:1 ~ 0.2:1
Shell: elongate conical; fragile; small to moderately small. Exterior colour white, somewhat brownish. About 14.5 whorls, convex; protoconch with ~1.5 whorls usually eroded,, smooth and glossy; teleoconch with ~13 whorls strongly convex, growing slowly. Suture moderately profound, intensely clear and slightly separated, moderately deep, widely open. Imperforate: umbilicus closed. Approximately 51 costae on the body whorl. Costae are fine, leaf-like, barely raised, thread-like. Occasional varix appearing randomly on the shell. Intercostal spaces with weak spiral threads giving a cancellate pattern with the costae. Interstices with approximately 15 spiral striae per whorl. Base moderately convex with weak basal disc and ridge. Columella barely reinforced by a cord. Aperture roundly ovate; peristome double; outer lip formed by the last varix; inner lip continuous, strongly leaf-like. Operculum horny, yellowish brown, paucispiral.
This species and the following one, A. (S.) hedleyi, are usually confused, but A. (S.) thielei is distinguishable from A. (S.) hedlevi by the surface sculpture. A. (S.) thielei has an almost uniformly cancellate surface, while A. (S.) hedlevi has a cancellate surface with some strong axial costae. A. (S.) thielei and A. (S.) hedleyi both have weak basal cords, which is a character of this subgenus.
Distribution:
Japan, Philippines.
Habitat:
10-100 m (Nakayama 2003: 20)
Etymology:
honors Johannes Thiele, a German zoologist who specialised in malacology
Type Material:
Holotype: MNHN 4335 for Amaea thielei (de Boury, 1913) - Type Locality: 'Japon' [Japan].. [Brown, L. & Neville, B.D., 2015]
Type not located [as Scalaria picturata Yokoyama, 1922] - Type Locality: Shito and Oji in Musashi, Japan.. [Brown, L. & Neville, B.D., 2015]
Type not indicated in text for Amaea thielei (de Boury, 1913) - Type Locality: 'Japon' and 'Philippines'. [Higo, S., Callomon, P. & Goto, Y., 1999]
arsint.com (2023).
10 mm, Mactan Island, Cebu. Dived at 50 m. November 2011
Distribution
as listed in source literature
Boury, E. de. (1913a).
Plate VIII. Fig. 8.
pp: 180.
Shell fragile, imperforate, elongate-conical, ornamented with numerous very fine, thread-like longitudinal ribs and closely spaced, delicate transverse cords.
Suture moderately deep, widely open, slightly oblique, in no way channeled. Total of 13 whorls preserved. Embryonic whorls partially missing, 1½ remain, smooth and glossy; the following whorls strongly convex, growing slowly, with very numerous, extremely fine, leaf-like, barely raised, thread-like longitudinal ribs, sometimes transformed into equally leaf-like varices, expanded more noticeably on the upper part of the lower whorls; crossed by numerous, irregularly arranged, thread-like transverse cords. The final whorl of the spire is smaller, marked with about 51 longitudinal ribs and around 15 transverse threads.
Base moderately convex, with fine radial riblets, bordered by an angled and concentric ridge. Aperture oval-rounded. Peristome double; the inner lip continuous, strongly leaf-like, slightly expanded in front, waxy in appearance; the outer peristome interrupted at the back, formed by the last varix. The columella is barely reinforced by a cord. Color white, somewhat brownish. Length 22 mm; maximum diameter 7 mm; maximum height of whorls 9 mm; aperture diameter 4.5ial riblets, bordered by an angled and concentric ridge. Aperture oval-rounded. Peristome double; the inner lip continuous, strongly leaf-like, slightly expanded in front, waxy in appear
Nakayama, T. (2003).
pp: 115. Plate 8. Fig. 1-3.
figs 1-3:
Amaca (Scalina) thielei (De Boury, 1912)
height 31.2 mm; breadth 10.3 mm (KC);
fig. 3, base
arsint.com (2023).