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Dating of the Limnadiidae family suggests an American origin of Eulimnadia

TitreDating of the Limnadiidae family suggests an American origin of Eulimnadia
Type de publicationJournal Article
Year of Publication2016
AuteursBellec, L, Rabet, N
Date Published02/2016

The spinicaudatan clam shrimp is a group of branchiopod crustaceans that has existed as far back as the Devonian and well-preserved fossils are known. Evidence of monophyly exists for only one family (Limnadiidae), which has a worldwide distribution and morphological conservatism. The evolutionary relationships among genera and diversification mechanisms are not deeply resolved as well as origin of the genus Eulimnadia. To address these issues, we constructed phylogenies of limnadiid clam shrimp, with both Bayesian inference and maximum likelihood methods to infer limnadiid evolutionary relationships. We then performed dated phylogenies using a relaxed clock of the Spinicaudata using fossil calibrations. Divergence date estimates show a perfect match with the break up of the Pangaea that could explain current limnadiid distributions; however the genus Eulimnadia apparently diverged 30 Ma ago. Eulimnadia phylogeography suggests an American origin and ecological patterns were analyzed to propose hypotheses on its origin and spread. This genus also shows a strong dispersive capacity, which could be explained by its reproduction modalities (androdioecy). This study and this first phylogeny with fossil calibration date the current distribution of Spinicaudata and reveal congruence with continental drift, except for Eulimnadia.