Carinaria cithara forma cithara Benson, 1835c
Overview
This is a large shelled pelagic snail, up to 5 cm long, with an almost completely transparent body. The body can never withdraw into the shell. The Carinaria c. cithara shell is high pyramidal. Only the broad triangular visceral nucleus is darkly pigmented. The large eyes, with black retina, and the mouth organs are clearly seen. The intestine is frequently full and visible. The body is long and cylindrical with one swimming fin (Carinaria c. cithara 1). It hunts large prey such as fish, shelled pteropods and other heteropods. It lives in upper layers of the warm waters of the Indo-Pacific.
Taxonomic Description
This is an elegant species with a high shell. Cutis of moderate thickness with only a few tubercles in larger specimens. Fin with sucker in both sexes. A small depressed crest is found on the relatively high tail. The most typical feature is the slender, cylindrical eyes where the base is only slightly smaller than the lens (Carinaria c. cithara eyes). The left tentacle is present, but the right one is absent. The shell is perfectly triangular but higher and with a smaller top angle (about 30°) than in Carinaria cristata forma japonica. The transverse striation is nearly straight and parallel. The keel is narrow. The embryonic shell with 3.5 whorls, has two sculpture lines on the second whorl. This coiled part is found on the very top of the teleoconch. As the embryonic part is relatively small, the Carinaria c. cithara viscera shows no coiling, but forms a straight rod.
Body length up to 50 mm.
Juveniles
The juveniles have a small, dextrally coiled shell. A special description is not available.
Reproduction
In this form the sexes are separate.
Ecology
This form is carnivorous and epipelagic.
Distribution
Like Carinaria c. cristata it is only found in the Indo-Pacific Oceans. Its distribution range seems restricted to equatorial waters, see the Carinaria c. cithara map.
Types
Carinaria cithara Benson, 1835: 215.
Types: originally 4 spec. are described but probably not preserved
Type locality: 4°30'S-4°30'N, 87°30'E-90°30'W. Coll.: Benson.