The age, ancestral distribution and radiation of Chimarra (Trichoptera: Philopotamidae) using molecular methods

- We reconstruct the phylogeny of Chimarra (Trichoptera: Philopotamidae).
- We examine the relationships within the genus, as well as relations to sister genera.
- By using dispersal-extinction-cladogeneis we resolve the ancestral distribution of the genus.
- We show that the subgenera are monophyletic and geographically distinct.
- We illustrate the radiation from the South American continent throughout the world.

The phylogeny of Chimarra has previously been examined using morphological characters for a smaller subset of taxa and geographical representativeness. Here molecular data from three genes (COI, CAD and POL-II) are used to reconstruct the phylogeny of the genus. The results show Chimarra to be monophyletic, and that some of the sister groups are paraphyletic. Previous hypotheses regarding the relationships of subgenera within the genus are corroborated but incongruences are also found compared to morphological characters that have been used in keys. The origin of the genus is explored using three different hypotheses of biogeographical region. The biogeography analyses reveal an origin in the Neotropical region and a subsequent rapid radiation, with dispersal into the Oriental, Palaearctic and Australasian regions and secondarily to the Nearctic region. The Afrotropical region has been colonized in several independent events. The molecular dating using a relaxed clock and calibration with four fossil species indicates that Chimarra is about 138 million years old, and that the radiation out of the Neotropical region occurred approximately 124 million years ago.

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