Epitonium agitabile
(Jousseaume, 1912)
Description:
Dimensions range from 7.5 mm - 10 mm high and 4 mm wide.
Width to height ratio: 0.53:1 ~ 0.4:1
Shell: elongate, slender and regularly conical; solid; small. Exterior colour white, shiny, almost polished. About 9 whorls, closely set; protoconch with ~3 whorls smooth, slightly yellowish, apex elongated, bluntly pointed; teleoconch with ~6 whorls striated. Suture deep. Imperforate. Approximately 9 costae on the body whorl. Costae are erect. Costae notched at the suture; angular at the back. Intercostal spaces with faint spiral striations. Columella thin, slightly curved, and rests on the varices of the penultimate whorl. Aperture rounded-oval; peristome thickened and slightly roughened, while the inner part is smoother.
Jousseaume [1912] states that the shell resembles Scalaria subauriculata Souverbie but differs in having more numerous ribs, finer striations, more pronounced rib angles, and a simpler peristome edge. It also resembles Scalaria tenuicostata Sowerby but has stronger, fewer, and more rounded ribs without spiny projections. Additionally, the largest diameter of the aperture is significantly less oblique than in tenuicostata.
Distribution:
Red Sea - Djibouti
Habitat:
not reported
Etymology:
[latin] from agitabilis = easily moved. The name agitabilis probably refers to the shell's small size, delicacy, and lightness, making it easily disturbed or set in motion in its marine environment.
Type Material:
Syntype: Paris Museum 2683 for Epitonium agitabile (Jousseaume, 1912). [Kaicher, S.D., 1981]
Syntype: MNHN 4197 [as Graciliscala agitabilis Jousseaume, 1912:] - Locality: Djibouti. [Brown, L. & Neville, B.D., 2015]
Kaicher, S.D. (1981). Card #: EP2-3110.
Distribution
as listed in source literature
Jousseaume, F. (1912).
Plate VI. Fig. 29-30.
pp: 208.
The shell is imperforate, elongate-conical, solid, white, shiny, ribbed, and almost polished with faint spiral striations. It has nine convex whorls that grow regularly and are closely set, separated by a deep suture. The first three whorls are smooth and slightly yellowish, while the following six are lamellar and striated. The varices are angular at the back and notched at the suture. The aperture is rounded-oval, with a thickened and slightly roughened outer and anterior peristome, while the inner and posterior parts are smoother.
Length: 7.5 mm, Diameter: 4 mm.
Habitat: Djibouti, very rare.
Plate 209.
Kaicher, S.D. (1981).