A time-calibrated multi-gene phylogeny of the diatom genus **Pinnularia**

Pinnularia is an ecologically important and species-rich genus of freshwater diatoms (Bacillariophyceae) showing considerable variation in frustule morphology. Interspecific evolutionary relationships were inferred for 36 Pinnularia taxa using a five-locus dataset. A range of fossil taxa, including newly discovered Middle Eocene forms of Pinnularia, was used to calibrate a relaxed molecular clock analysis and investigate temporal aspects of the genus diversification. The multi-gene approach resulted in a well-resolved phylogeny of three major clades and several subclades that were frequently, but not universally, delimited by valve morphology. The genus Caloneis was not recovered as monophyletic, confirming that, as currently delimited, this genus is not evolutionarily meaningful and should be merged with Pinnularia. The PinnulariaCaloneis complex is estimated to have diverged between the Upper Cretaceous and the early Eocene, implying a ghost range of at least 10 million year (Ma) in the fossil record.

Language

English

Source (journal)

Molecular phylogenetics and evolution. - Orlando, Fla

Publication

Orlando, Fla : 2011

ISSN

1055-7903

Volume/pages

61 :3 (2011) , p. 866-879

ISI

000297387600024