Molecular phylogeny of the Trechus brucki group, with description of two new species from the Pyreneo-Cantabrian area (France, Spain) (Coleoptera, Carabidae,Trechinae)

A molecular phylogeny of the species from the Trechus brucki clade (previously T. uhagoni group) based on fragments of four mitochondrial genes and one nuclear gene is given. We describe Trechus (Trechus) bouilloni sp. n. from the western pre-Pyrenees: Sierras de Urbasa-Andia, Navarra, Spain. The species was collected in mesovoid shallow substratum (MSS), a subterranean environment. Molecular as well as morphological evidences demonstrate that the new species belongs to the Trechus brucki clade. A narrow endemic species of high altitude in western French Pyrenees merged with T. brucki Fairmaire, 1862a, T. bruckoides sp. n., is described. A lectotype is designated for T. brucki and T. planiusculus Fairmaire, 1862b (junior synonym of T. brucki). The species group is redefined based on molecular and morphological characters, and renamed as the brucki group, as T. brucki was the first described species of the clade. A unique synapomorphy of the male genitalia, a characteristic secondary sclerotization of the sperm duct, which is shared by all the species of the brucki group sensu novo, is described and illustrated. The T. brucki group sensu novo is composed of Thechus beusti (Schaufuss, 1863), T. bouilloni sp. n., T. brucki, T. bruckoides sp. n., T. grenieri Pandelle, 1867, T. uhagoni uhagoni Crotch, 1869, T. uhagoni ruteri Colas, 1935 and T. pieltaini Jeannel, 1920. We discuss the taxonomy of the group and provide illustrations of structures showing the differences between the species, along with distribution data and biogeographical comments.