Massya longicirrata (Massy, 1917)
Overview
This is a small naked pelagic snail, up to 0.4 cm long, with a mainly transparent body and long tentacles trailing behind the body. It lives in the N-Atlantic Ocean in deeper water layers. Its is a carnivorous species (Massya longicirrata).
Taxonomic Description
Body rounded, unpigmented, frequently with ciliary bands. No buccal arms or cones present. The anterior tentacles are very long and trail behind the body, exceeding its length. These tentacles are homologous with the head palps. The base of the tentacles are muscle-rich and broad, above the bases they rapidly become thinner and devoid of nerve endings. The wings, of which the left is always smaller than the right, are very broad and round distally. At the posterior margin of the wings, where they come together, a small projection is apparent. This projection seems to be equivalent to the posterior footlobe, as muscle tracks can be traced originating from the projection, crossing the relative vast expanse of the fin bases and ending near the minute lateral lobes. The distance between the lobes is as large as in Thliptodon species. No lateral or posterior gills are present. Pruvot-Fol stated that the specimens had a tetraradiate gill, but Massy and Tesch did not observed these. The first author could trace only a posterior gill ring and lateral crests. The radula is very large and shows large arcuate, dentated median plates with 40 to 50 small cusps at their free border, lateral teeth broad based. The radula formula is 3-1-3. There are 11 to 16 transverse rows of median plates and 8 to 9 rows of laterals. The hooks, of which there are 16 to 20 at each side, are minute triangular, subequal in size. The jaw is composed of a row of small spines.
Maximum body length 3.5 mm.
Juveniles
A special description is not available.
Reproduction
This species is a protandric hermaphrodite.
Ecology
This species is a carnivore.
Distribution
It is meso-, mostly bathypelagic, living below 1000 m. The distribution in the E-Atlantic resembles the Atlanto-Mediterranean Centre type of dispersal as shown in the Massya longicirrata map. Probably its bathypelagic character is responsible for its absence in the Mediterranean.
Types
Clionopsis longicirrata Massy, 1917: 235, pl. 8, fig. 3.
Types: the 2 spec. concerned have not been found.
Type locality: 50°59'N 11°52'W. Coll.: CHCE stat. 481.