Family PERIMENIIDAE
Compiler and date details
A.H. Scheltema, Woodshole Oceanographic Institute, Massachusetts, USA
Introduction
The Perimeniidae (= Pruvotinidae, Pararrhopaliidae), a family of Neomeniomorpha, is ill-defined. The presence of hollow, fishhook-shaped spicules and radula morphology of two upright hooks per row were used by Scheltema & Schander (2000) as the criteria to include five of the ten genera together, without designating a taxon. The remaining five genera do not have barbed spicules (see Salvini-Plawen 1978).
Perimeniid species are the most numerous and diverse neomenioids in Australia. For instance, at one 400-m depth station on the south-eastern continental slope of Australia, 398 individuals and nine species were collected in a single sample (Scheltema 1990). One species, Eleutheromenia bassensis Scheltema & Schander, accounted for 30% of all neomenioids collected in Bass Strait; and of 172 neomenioids collected there, 110 or 64% were perimeniids (Scheltema 1998). Australia shares with Antarctica high numbers and diversity of perimeniid species (Scheltema 1990). However, of the nine species known from Australia, so far only two have been described, in the genus Eleutheromenia Salvini-Plawen from Bass Strait.
Perimeniidae are a morphologically diverse group. Among the five with fishhook-shaped spicules some are short and stubby, less than 4.5 mm, and very spiny or somewhat rough, whereas others may be slender and up to 8 mm and either spiny or smooth. Barbed spicules may be abundant or sparse. Integumental papillae may be present or absent. The radula is distichous with denticulate hook teeth. Paired dorsal salivary glands that open through a papilla into a dorsal pharyngeal pocket may be present or absent; ventral salivary glands may open through ampullae or ducts. Copulatory spicules may be present or absent. In Eleutheromenia, there is a large accessory 'ovigerous' gland connected with the pericardium. Gill folds may be present as papillae or as a few low folds (Scheltema & Schander 2000).
General References
Salvini-Plawen, L.v. 1978. Antarktische und subantarktische Solenogastres (eine Monographie: 1898–1974). Zoologica (Stuttgart) 48(1/2): 1-315
Scheltema, A.H. 1990. The Aplacophora as a Tethyan slope taxon: evidence from the Pacific. Bulletin of Marine Science 47: 50-61
Scheltema, A.H. 1998. Class Aplacophora. pp. 145-147 in Beesley, P.L., Ross, G.J.B. & Wells, A. (eds). Mollusca: The Southern Synthesis. Fauna of Australia. Melbourne : CSIRO Publishing Vol. 5(Part A) pp. xvi, 1-563
Scheltema, A.H. & Schander, C. 2000. Discrimination and phylogeny of solenogaster species through the morphology of hard parts (Mollusca, Aplacophora, Neomeniomorpha). Biological Bulletin. Marine Biological Laboratory (Woods Hole) 198: 121-151