Pruvotella danae Pruvot-Fol, 1942
Overview
This is a medium sized naked pelagic snail, up to 1 cm long, with a moderately transparent body. The body shape is oval, pointed posteriorly; only a distinct lateral gill present. It is a carnivorous species, living in the Indo-Pacific Ocean (Pruvotella danae).
Taxonomic Description
The posterior gill resembles that of Cliopsis krohni (Pruvotella danae gill). It has a rounded hexagonal shape, with four extremely small radiating branches of which the right one is undulated. Tesch (1950) gave the first picture of the entire animal, however, he did not indicate undulations in on any of the small radiating branches. This agrees with the observations of the first author. The lateral gill, so typical for this genus, is even more developed than in Pruvotella pellucida and it nearly surrounds the body. The animal closely resembles Cliopsis and it is only distinguished by its lateral gill. The foot is rather small, horseshoe shaped and the posterior lobe is lacking. The head parts are small. The proboscis is well developed, the muscular part, however, is shorter than in Cliopsis. The membraneous proboscis section is extremely long, the oesophagus itself is short. The well developed wings are broad. The hook sacs, which are close to those of Cliopsis, contain numerous long hooks with curved tips. The hooks, about 40 in each sac, are all implanted in the same level. Transverse annulae mentioned by Pruvot-Fol, were not recorded by Tesch and Van der Spoel (1976). The jaw is situated on a papilla, carrying numerous spines packed closely together. Figures and description by Pruvot-Fol, and Tesch of the jaw are not clear in all points, but we may conclude that the spines are surrounded by the real jaw, composed of two chitinous plates triangular in shape. The structure of the jaws and configuration of the radula is certainly different from all other Gymnosomata. The Pruvotella danae radula formula is 7-1-7 (5-1-5 in spec. smaller than 5 mm). The median plate and the first lateral plate are very robust. Pruvot-Fol described the important difference between the first and subsequent lateral plates, it is however not found in Thliptodon. It should be noted that the first lateral plate is slightly different from the subsequent laterals in many gymnosomatous genera. The median plate is rather large, having three cusps of which the median one is the shortest. The length of the first lateral plate is 1/3 the length of the outerside laterals. This species, though possessing a lateral gill, has many characters in common with Cliopsis and with Pruvotella pellucida; so Pruvot-Fol (1942) hesitated in maintaining the new genus Pruvotella for these two species. The species Pruvotella danae may form a link between this genus and Cliopsis.
Body length up to 10 mm.
Juveniles
A special description is not available.
Reproduction
This species is a protandric hermaphrodite.
Ecology
This species is a carnivore.
Distribution
Like Pruvotella danae it is very rare. It was only collected three times as shown in the Pruvotella danae map.
Types
Pruvotella danae Pruvot-Fol, 1942: 17, figs. 13-16.
Holotype: ZMUC (alcohol collection).
Type locality:29°37'.'5 S 156°46'E. Coll.: CDAE, stat. 3665iv.