The genus is diagnosed as follows: Shell small, oval. Surface finely striated, sculpture more pronounced around umbo. Hinge plate narrow, cardinal teeth straight. Ligament external, elevated over dorsal margin. Only one (exhalant) siphon present; inhalant opening merged with pedal slit due to loss of presiphonal suture; ventral pair of siphonal retractors well developed, placed at posterior end of pedal slit. Outer demibranch absent. Brood pouch localised dorsally, formed by 7-20 filaments (depending on size). Lateral loop of nephridium clearly visible from dorsal side.
The species differs from Euglesia in having an exterior ligament exterior, an elongate, moderately convex shell which is sculptured with fine, dense striations. The shell reaches 2.5 mm in length.
Afropisidium aslini (Kuiper, 1983)
Common name: Pea shell, pea clam, pill clam
Class Bivalvia
Infraclass Heteroconchia
Cohort Heterodonta
Megaorder Neoheterodontei
Order Sphaeriida
Superfamily Sphaerioidea
Family Sphaeriidae
Genus Afropisidium Kuiper,1962 (Type species: Pisidium lepus Kuiper, 1957 = Pisidium pirothi Jickeli, 1881).
Original name: Pisidium aslini Kuiper,1983. In Kuiper, J. G. J. (1983). The Sphaeriidae of Australia. Basteria 47: 3-52.
Type locality: Left bank at junction of Moleside Creek, Glenelg River, Victoria.
Shallow burrower, suspension and deposit feeder. Inhabits creeks, is often associated with Euglesa tasmanica (Korniushin, 2000). Broods young.
Western Victoria and northern Tasmania.
This genus was considered to be a subgenus of Pisidium by earlier workers and was treated as such in earlier versions of this key. Molecular studies (e.g. Lee and Ó Foighil, 2003) have shown that it is a distinct genus.
Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing.
Korniushin, A. V. (2000). Review of the family Sphaeriidae (Mollusca: Bivalvia) of Australia, with the description of four new species. Records of the Australian Museum 52: 41-102.
Korniushin, A. V. (2002). Morphological characters analysis, the intergroup phylogenetic relationships and possible outgroups of the family Sphaeriidae (Mollusca, Bivalvia). Vestbuj zoologii 36(4): 3-22.
Kuiper, J. G. J. (1962). Note sur la systematique des pisidies. Journal de Conchyliologie 102: 53-57.
Kuiper, J. G. J. (1983). The Sphaeriidae of Australia. Basteria 47: 3-52.
Lamprell, K. & Healy, J. (1998). Bivalves of Australia, volume 2. Leiden, Backhuys Publishers.
Lee, T. (2019). Sphaeriidae Deshayes, 1855 (1820). Pp. 197-201 in C. Lydeard & Cummings, K. S. Freshwater Mollusks of the World: a Distribution Atlas. Baltimore, John Hopkins University Press.
Lee, T. & Ó Foighil, D. (2003). Phylogenetic structure of the Sphaeriinae, a global clade of freshwater bivalve molluscs, inferred from nuclear (ITS-1) and mitochondrial (16S) ribosomal gene sequences. Zoological Journal of the Linnean Society 137: 245-260.
