Karyotype of Lasaea australis, a brooding bivalve species

Abstract

Karyological investigations have been carried out on the only known cross-fertilizing Lasaea species, L. australis, a marine brooding bivalve with a pelagic larval development. The karyotype consists of 18 pairs of chromosomes (2n = 36), including four metacentric, six submetacentric, three subtelocentric and five telocentric pairs. Comparison with other known Lasaea karyotypes shows that L. australis can be considered as ancestral, and its asexual and direct-developing congeners are characterized by mechanisms of polyploidy.