Atlanta tokiokai

Atlanta tokiokai Van der Spoel and Troost, 1972


This is a medium sized, dextrally shelled, pelagic snail, 0.3 cm in diameter with large eyes and a single swimming fin. The shell is strongly flattened and keeled. The faint yellow spire is small, oblique. The spire has spiral lines. On the whole shell spiral and faint transverse sculpture is present. The operculum is relatively thick. It is a carnivore predating on relatively large zooplankton. This species occurs in the Indian and Atlantic Oceans (Atlanta tokiokai 2).

Taxonomic Description [after Richter, 1990]

Medium size shell with the keel penetrating slightly in between the body whorl and preceding one. The shell is faint yellow, the inside of the aperture is brown. The spire has 5 closely coiled whorls, the whorls are slightly convex. The top angle is 80°. (Atlanta tokiokai). The whole shell is covered with spirally arranged rows of tubercles and radial striae are very faint. The spire is strongly oblique (Atlanta tokiokai from lateral). The suture is shallow (Atlanta tokiokai 1). The shell is flattened between the narrow umbilicus and the line continuing from the keel. The inner walls of the whorls in the spire are decalcified. The operculum (type C) is monogyre and thick. The eyes are of the type B. The radula is small and ribbon-shaped.
Shell diameter up to 3 mm.


The juveniles (Atlanta tokiokai veliger) have a small dextrally coiled shell. The juvenile shell is conical to globose with a blunt tip and round contour of the whorls. The Atlanta tokiokai protoconch I is smooth the protoconch II is covered by typical spiral lines composed of fine dots.


In this form the sexes are separate.


This species is carnivorous and epipelagic.


This species is found in the Pacific and Indian Oceans and the Caribbean, see the Atlanta tokiokai map.


Atlanta tokiokai Van der Spoel and Troost, 1972: 2, figs. 1-3.
Holotype: ZMAN, dissolved (alcohol collection).
Type locality: 12°01.6'-12°02.3'N 68°22'38"-68°25'0'W, Coll.: Cicar Expedition, stat. 60.