Diacavolinia deshayesi Van der Spoel, Bleeker and Kobayasi, 1993
Overview
This is a medium sized, uncoiled thecosomatous pteropod, 0.8 cm long. It has a flat dorsal side with moderately developed ribs. The ventral side is vaulted. The caudal spine is absent and a caudal spine mark is not left as the ventral and dorsal sides grow together. The lateral spines are well developed. Shell sculpture consists of faint growth lines and faint transverse striation. The slender dorsal lip has a notch a constriction and a gutter. Micro-zooplankton and phytoplankton are its food and it is a mucus feeder. It lives in the Atlantic Ocean at shallow depths (Diacavolinia deshayesi).
Taxonomic Description
The hyaline shell is not typically triangular; there is a faint brown to rose hue over the whole shell. The dorsal lip has a, sometimes small, notch in the slender rostrum, a constriction and a gutter. The ventral lip is relatively large and shows a clear median depression. The well-developed lateral spines are slightly bent, sharply pointed and hooked; the gutter corners are large. The 27 distinct ventral ribs are comb-shaped the number of ribs varies from 20 to 40. On the dorsal side ribs are present as well. The lateral lines are slightly convex and the flanks are slightly developed. The dorsal side is convex, with a strong central rib and latero-dorsal ribs; the lock ribs are small. The lock area is large like the main tubercle and link. Lunar and minor tubercle are typical. A tiny secondlock system is present. The growth lines are also well developed on the dorsal side. A hump is absent. The protoconch II area projects moderately. In the holotype the caudal joint is 0.64 mm; the nearly straight caudal fold is 1.20 mm long. There is an indication of lip flaps; moderate lip bellies and well-developed lip shoulders are present. The aperture is narrow. In the holotype the lip angle is about 140°, the lock angle is 74°, and the side angle is 72°.
The shell length ranges from 8.16 to 3.12 mm and the width from 6.72 to 2.80 mm.
Juveniles
A special description for this form is not available, see Diacavolinia longirostris.
Reproduction
This species is a protandric hermaphrodite.
Ecology
This species is phytophagous.
Distribution
Diacavolinia deshayesi occurs in the Atlantic and is described here from the N-Atlantic Ocean, see the Diacavolinia deshayesi map.
Types
Diacavolinia deshayesi Van der Spoel, Bleeker and Kobayasi, 1993: 145, fig. 21.
Holotype (ZMUC. gas. 164) in ZMUC and 8 paratypes (ZMA. moll. 3.92.024) in ZMAN.
Type locality: 5°06'N 51°35'W, 0-50 m depth, Dana Exped., Stat. 1175 iii, 17 September 1929.
Etymology: The name is given in honour of Dr. G.P. Deshayes who described taxa in this group.