Subgenus Minitrechus Vigna Taglianti & Magrini, 2010

Faille, Arnaud, Hofmann, Sylvia, Merene, Yeshitla, Hauth, David, Opgenoorth, Lars, Woldehawariat, Yitbarek & Schmidt, Joachim, 2023, Explosive radiation versus old relicts: The complex history of Ethiopian Trechina, with description of a new genus and a new subgenus (Coleoptera, Carabidae, Trechini), Deutsche Entomologische Zeitschrift 70 (2), pp. 311-335 : 311

Subgenus Minitrechus Vigna Taglianti & Magrini, 2010

Type species.

T. gypaeti Vigna Taglianti & Magrini, 2010.

New synonymy.

Archeotrechus Magrini, Quéinnec & Vigna Taglianti, 2012 (type species: T. relictus Magrini, Quéinnec & Vigna Taglianti, 2012), syn. nov.

Remarks.

Based on the molecular data, all Trechus species known to occur in the mountains of southern Ethiopia (Bale and Arsi Mountains, Gughe Highlands), form a monophyletic clade (Fig. 3 ). This clade includes species characterized by widely differing body sizes, shapes, and proportions, and by many other morphological characters, including elytral chaetotaxy, the number of dilated male protarsomeres, and the extent of the dorsal opening of the aedeagal median lobe. Similar character states can likewise be found in Trechus sensu lato species occurring in northern Ethiopia which, however, do not cluster within the south Ethiopian clade. At the current state of knowledge, a morphological definition of this clade together with a differential diagnosis with respect to other species groups of Trechus sensu lato cannot be presented here and require more comprehensive morphological investigations.

For the monophyletic southern Ethiopian Trechus clade, the oldest valid species group name is Minitrechus Vigna Taglianti & Magrini, which was given for a very tiny, depigmented species from Mt. Enkuolo ( Vigna Taglianti and Magrini 2010). The subgenus Trechus Archeotrechus Magrini, Quéinnec & Vigna Taglianti was described two years later for a likewise tiny and depigmented species from the Bale Mountains, which is additionally characterized by a very wide dorsal opening of aedeagus ( Magrini et al. 2012). In our phylogeny, the type species of both of these subgenera cluster together within one of the two main clades of South Ethiopian Trechus , both of which are highly supported by the molecular data (Fig. 3 ). Consequently, the status of Archeotrechus as a separate subgenus within Trechus sensu lato can no longer be maintained.

A complete list of species we propose to summarize within the subgenus Trechus Minitrechus , is shown in the checklist of the Ethiopian Trechini species, see Discussion, below.

Figures

Figure 3. Subtree of the ultrametric time-calibrated phylogeny of Trechini beetles as shown in Fig. 2 (see there for details). Collapsed, colored clades refer to previous results of Faille et al. (2013). Clades which include Ethiopian Trechus (sensu lato) species are highlighted by different colors (see text for details).