Pneumoderma peroni (Cuvier, 1817) forma heterocotylum (Tesch, 1903)
Overview
This is a naked pelagic snail, up to 0.5 cm long, with semi-transparent body and the visceral mass is seen through the body wall. The wings are small, the posterior footlobe is large. It is rounded oval in shape. There are two lateral arms, each with 60-150 suckers of different types. It hunts zooplankton, and lives in the Indo-Pacific Ocean at shallow depths (Pneumoderma p. heterocotylum).
Taxonomic Description
The body is yellowish, with darker pigmented head parts. Posterior gill well developed, the ventral and dorsal side of the quadrangular crest are fringed; radiating crests well developed, each bearing five to six subdivided fringes. Lateral gill with fringed lateral somatic crests. The acetabuliferous arms have a bunch of about 30 small, short stalked suckers at their base, in between these bunches two groups of about 25 long stalked, elongated suckers are found (Pneumoderma p. heterocotylum suckers). Lateral footlobes are small, median lobe rather long. Hook sacs extremely long with 20 strongly bent hooks.
Body length up to 5 mm.
Juveniles
A special description is not available.
Reproduction
This species is a protandric hermaphrodite.
Ecology
This species is a carnivore.
Distribution
This species is found in the Indo-Malayan waters, see the Pneumoderma p. heterocotylum map.
Types
Pneumonoderma heterocotylum Tesch, 1903: 114 (1904), pl. 5, figs. l l 8-119.
Holotype: ZMAN (alcohol collection), u.s.
Type locality: 1°4'5S 127°52'6E. Coll.: Siboga, stat. 143.