Molecular evolution of the Lake Baikal endemic caddisflies (Trichoptera)

Abstract

Phylogenetic relationships of the nine Lake Baikal endemic caddisfly species with the representatives of the genus Apatania (Apataniidae) were reconstructed on the basis on nucleotide sequences of the mitochondrial COI gene. The results of Bayesian analysis pointed to the relationships of the endemics with the North American Apatania incerta (Banks, 1897) and A. sorex (Ross, 1941). The divergence of the genetic lineages of the Baikalian and Nearctic apataniids occurred in the Late Oligocene–Early Miocene. On the dendrogram, endemic species formed two monophyletic clades corresponding to the tribes Thamastini and Baicalinini. It was also found that the genus Protobaicalina was polyphyletic, while the genus Baicalina was a species flock. Our analysis showed that the nearest common ancestor of the studied Baikal caddisfly species existed about 21 Mya, while the modern species composition of endemic fauna dates back to Pliocene–Pleistocene age (2.5–0.7 million years).