Diacavolinia deblainvillei Van der Spoel, Bleeker and Kobayasi, 1993
Overview
This is a medium sized, uncoiled thecosomatous pteropod, 0.7 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 dorsal lip has a notch but no constriction and a gutter is present. Micro-zooplankton and phytoplankton are its food and it is a mucus feeder. It lives in the W-Atlantic Ocean at shallow depths (Diacavolinia deblainvillei).
Taxonomic Description
The colourless hyaline shell is not typically triangular. The dorsal lip has a notch in the rostrum but no constriction, there is a shallow gutter. The ventral lip is of typical in size and shows a median depression. The ventral side is convex. The short lateral spines bent dorsally; they are hooked and sharp. The dorsal side is convex, the central rib and latero-dorsal ribs are well developed and the lock ribs are well developed though small. The ventral ribs, 23 in number, are strongly developed, comb-shaped. The flanks are present. The lock area is small. Main and lunar tubercles are normal, the minor tubercle is absent. A secondlock system is present. The growth line pattern is typical. There is no hump. The protoconch II area does not project far. In the holotype the caudal joint is 1.20 mm; the somewhat moon-shaped caudal fold is 1.20 mm. There are no lip flaps; the lip bellies are pronounced and the lip shoulders are small. The aperture is wide. In the holotype the lip angle is smaller than 150°, the side angle is 80° and the lock angle is 78°. The aperture rim is sharp, the ventral rim is slightly thicker.
The shell length ranges from 6.88 to 3.60 mm and width from 5.36 to 3.04 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 deblainvillei is restricted to the W-Atlantic and probably restricted to epipelagic zones, see the Diacavolinia deblainvillei map.
Others
The closest morphological species is Diacavolinia souleyeti which differs from Diacavolinia deblainvillei in having a larger lip angle and lacks a lip shoulder.
Types
Diacavolinia deblainvillei Van der Spoel, Bleeker and Kobayasi, 1993: 139, fig. 9E, 12.
Holotype (ZMA. moll. 3.92.012) and 11 paratypes (ZMA. moll. 3.92.013) in ZMAN.
Type locality: 38°45'N 72°20'W, 0-100 m depth, July 1975, Deepwater Dumpsite 106 project, cruise 2, Stat. 67-M.
Etymology: The name is given in honour of Dr. H.M.D. De Blainville who described many pteropods.