Phylogenetics of Thysanoptera: Timing and tempo of thrips evolution

Thysanoptera, from the early Cretaceous, have become extremely diverse and exhibit a wide range of social and feeding behaviors that are of particular interest in evolutionary studies.  However, the current classification and dating of thrips divergences have never been formally evaluated with a comprehensive molecular analysis of thrips phylogeny.  To provide a foundation of future evolutionary studies, the objectives of this study are to (1) test the monophyly of the suborders Terebrantia and Tubulifera, (2) test the monophyly of the families/subfamilies and decipher their relationships, and (3) infer divergence dates of major thrips groups.  Phylogenies reconstructed are based upon 5299 bp, from five genetic loci: 18S ribosomal DNA, 28S ribosomal DNA, Histone 3 (H3), Tubulin-alpha (TubA) and cytochrome oxidase c subunit I (COI).  103 taxa represent 99 thrips species from seven of the nine families, all six subfamilies and 70 genera were sequenced. All analyses strongly support a monophyletic Tubulifera and Terebrantia. Phlaeothripidae, Aeolothripidae, Melanthripidae and Thripidae are all monophyletic families.  The relationship between Aeolothripidae and Merothripidae to the rest of Terebrantia is equivocal. Four of the six subfamilies are recovered as monophyletic.  The two largest subfamilies, Phlaeothripinae and Thripinae, are paraphyletic and require further study to understand relationships within them.  With fossil data for calibration, it is suggested that the divergence of Tubulifera and Terebrantia occurred early than predicted, during the Triassic (~230 Mya).  The major groups of Terebrantia diverge in the late Jurassic and most of thrips diversity appears during the Cretaceous and Tertiary periods.