Trechosia Jeannel, 1926

Geginat, Gernot, 2007, A new species group of the genus Trechosia from the Cape region of South Africa (Coleoptera, Carabidae, Trechinae), Zootaxa 1469, pp. 43-50 : 43-44

The genera Trechosia Jeannel, 1926 and Cothresia Jeannel, 1964

The genus Trechosia was primarily erected for Trechus solutilis Péringuey. The genus currently comprises nine species from southern Africa and a single species, T. aberdarensis Jeannel , from the Kenyan Abardares Highlands. The genus Trechosia is well characterized by the particular elytral striation pattern as well as by the formation of the aedeagus. The three inner elytral striae are deeply impressed while the outer elytral striae are almost totally effaced. The 3rd elytral stria characteristically begins at the anterior discal setiferous puncture and strongly bends inwards towards the apex. The internal sack of the aedeagus is armed by a single large copulatory piece or even is unarmed as in T. atterima (Péringuey) . The genus Trechosia was divided into two species groups by the position of the posterior discal setiferous puncture ( Jeannel 1960, 1964). The posterior discal setiferous puncture is positioned in the third elytral stria in the T. monticola group, while in the T. solutilis group it is positioned in the third interstria.

The genus Cothresia was erected by Jeannel for four species from South Africa ( Jeannel 1964) and currently also includes five additional species from Ethiopia ( Basilewsky, 1974). Jeannel in his original description already noted that the genus comprises a disparate group of species. After examination of the type material of all species of the group I can confirm this observation. The genus clearly has to be revised in order to represent a monophyletic group. The type species of the genus, C. curta is characterized by a deeply impressed recurrent sutural stria ending abruptly within the apical quarter of elytra not merging into the 5th elytral stria which is totally effaced. The recurrent sutural stria is much longer and deeper impressed than in Trechosia . The aedeagus of C. curta is reminiscent to the genus Pachydesus . It differs from Trechosia by the more truncated shape as well as by the complex, highly modified internal structures of the internal sack.