Many marine invertebrate clades exhibit diverse developmental modes, including planktotrophic, lecithotrophic and direct development. Evolutionary transitions among the developmental modes can be common and may have macroevolutionay consequences. The marine bivalve genus Lasaea (Brown, 1827) is composed of almost exclusively direct developing species, except for one planktotrophic species — Lasaea australis (Lamarck, 1818). To test whether L. australis represents an independent evolution of planktotrophic development or the retention of an ancestral trait, we estimated the ancestral developmental mode for Lasaea using phylogenetic comparative approaches. Our results show that the ancestral developmental mode of Lasaea is likely planktotrophic and multiple independent evolution of direct development has occurred in this genus. The repeated loss of planktotrophic development may be linked to the unusual asexual reproductive mode in Lasaea, but this hypothesis needs to be further corroborated. Our analyses also highlight the importance of using biologically realistic models for ancestral state reconstructions.