Peraclis michaelsarsi (Bonnevie, 1913)
[dubious species]
Overview
This is a pelagic snail with a left coiled shell, about 0.5 cm height; it has never been collected with shell intact so that a description cannot be given. The wings are fused into a swimming plate. This species lives usually at great depths in the Atlantic (see the holotype: Peraclis michaelsarsi).
Taxonomic Description
Tentacles symmetrical, without a sheath, the lips and footlobes form a trumpet-shaped proboscis. Wings are normally fused into a swimming disc. Central nervous system with separate abdominal ganglion. According to the original description the proboscis is more of the Cymbulia type, as the lateral and median lips are fused at the lateral points where they meet. However, their location in regards to body and head parts is the common Peraclis type. The radula formula is (1)-1-1-(1) (Peraclis michaelsarsi lateral). The intestine seems to be of type B as described for the Peraclis valdiviae.
Shell measurements are unknown, the maximum diameter of the swimming disc could not be measured.
Juveniles
The juveniles have a small left coiled shell. A special description is not available.
Reproduction
This species is a protandric hermaphrodite.
Ecology
This species is phytophagous and mesopelagic.
Distribution
If this is a valid species then the only record south of Iceland does not indicate its real distribution, however, if this species a synonym of Peraclis valdiviae its record indicates a more northern distribution in the Atlantic Ocean, see thePeraclis michaelsarsi map.
Types
Procymbulia michaelsarsi Bonnevie, 1913: 10, fig. 5, pl. 1, fig. 3.
Holotype (Peraclis michaelsarsi holotype): ZMVB 41046 (alcohol collection + I radula slide) u.s.
Type locality: 48°29'N 13°55'W. Coll.: CMSE, stat. 92.