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.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 33 • No. 2