Atlanta inclinata Souleyet, 1852a
Overview
This is a small dextrally shelled, pelagic snail, 0.7 cm in diameter with large eyes and a single swimming fin. The shell is large, strongly flattened and keeled. There are 7 whorls. The spire is large, blunt and oblique, and pink, it shows spiral sculpture. The operculum is monogyre. It is a carnivore predating on relatively large zooplankton. This species occurs in warm waters of all oceans (Atlanta inclinata 1).
Taxonomic Description [after Richter, 1990]
The shell is large. The spire is relatively large with about 4 whorls with slightly convex sides and moderately deep suture (Atlanta inclinata from apical). The spire is oblique and makes an angle of 80°. There are clear radial spiral and faint transverse striae on the spira. Over the whole shell except for the body whorl spiral lines of tubercles are found. The spire is slightly pink. The whorl formula of the shell varies between 1:0.27:0.13 and 1 : 0.56 : 0.32. In larger shells the keel penetrates in between the separated last whorls (Atlanta inclinata, Atlanta inclinata 2). The umbilicus is relatively narrow. The last whorl of the oblique spire has, at the underside, an elevation as a continuation of the keel base. The shell is flattened between this line and the umbilicus. The inner whorl-sides in the spire are decalcified. The operculum is monogyre. The radula is large, the increase in width is 31%. Median tooth is high and relatively broad, its basal plate is lunar-shaped, the lateral wings and median cusp are strong. The lateral teeth are robust, high with a strong top cusp. The lateral teeth are bend (Atlanta inclinata radula detail, Atlanta inclinata radula). The eyes are type B and the operculum is type C.
Shell diameter up to 7 mm.
Juveniles
The juveniles have a small, dextrally coiled shell. The Atlanta inclinata juvenile is broad conical with regular increasing whorls. The shell surface is nearly smooth (Atlanta inclinata protoc).
Reproduction
In this species the sexes are separate.
Ecology
This species is carnivorous and epipelagic.
Distribution
As many other species in this genus the inclinata group is restricted in its distribution to between 40°N and 30°S. The Atlanta inclinata map shows, certainly in the Indo-Pacific Ocean, an avoidance of the central areas of the oceans but in the Atlantic Ocean this phenomenon is not found. The map gives an incomplete picture and the distribution may be less discontinuous.
Types
Atlanta inclinata Souleyet, 1852: 275 (1841) pl. 19, figs. 9-15.
Lectotype: MHNP (alcohol collection). Paralectotypes: MHNP 8 specimens (alcohol collection).
Type locality: Atlantic Ocean. Coll. : Eydoux and Souleyet.