Baehria Schmidt & Faille, gen. nov.

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

Baehria Schmidt & Faille, gen. nov.

Figs 4-7 , 8-15

Type species.

Baehria separata sp. nov., herewith designated.

Diagnosis.

Representative of subtribe Trechina due to presence of bidentate mandibles (absence of retinacle) and dorsally closed aedeagal median lobe ( Jeannel 1926). Comparatively large trechines characterized by robust head, large mandibles, small but markedly protruded eyes, smooth, markedly convex tempora, cordiform pronotum, straight pronotal basal margin with large, rectangular to acute laterobasal angles, slender elytra, short metepisternum, reduced hindwings, moderately slender antenna and legs, protibia with a complete longitudinal groove on external surface, presence of a row of long adhesive hairs on apical margins of 4th tarsomeres which are as long as the 5th tarsomeres, and by a markedly slender median lobe of aedeagus, which possesses a small, slightly sclerotized endophallic copulatory piece. The new genus is particularly distinguished from other representatives of Trechina by unusual chaetotaxy of head capsule and elytra as follows: clypeus plurisetose, each side with 3-5 setae; submentum with three setae each side; anterior elytral discal seta located in the 4th interval, adjoined to the 4th stria.

Etymology.

The new genus name is given in memoriam of our dear friend and colleague, the distinguished entomologist Martin Baehr, Munich (10.03.1943-17.04.2019).

Description.

Head: Large and robust, without pilosity. Mandibles large, moderately slender, with bidentate dentition pattern as shown in Fig. 8 . Labrum with apical margin moderately emarginated, with six setae near apical margin. Clypeus each side with three or four setae (Figs 5 , 7 ; seldom only two setae at one of the sides). Eyes moderately small, as long as or slightly shorter than tempora, markedly convexly protruded (Figs 5 , 7 ). Two supraorbital setae each side in normal position for Trechina . Supraorbital furrows unevenly bent in posterior half, markedly deep in front and middle portions, slightly flatter near insertion of posterior supraorbital seta. Tempora markedly convex, markedly wrinkled to the neck, smooth. Mid of head convexly elevated, with a distinct transverse depression between supraorbital area and neck (Figs 5 , 7 ). Antennae slender, with third antennomere longest, 1/9-1/10 longer than first respectively fourth antennomere, and with second antennomere about 2/3 of length of third. Suborbital seta present. Apical tooth of mentum bifid, sensory pits of mentum present; submentum with three setae each side (Fig. 9 ).

Prothorax: Pronotum rather small, without pilosity, moderately transverse, cordate, broadest distinctly before middle, with lateral margin markedly concave before base, and with basal margin slightly smaller than apical margin (Figs 4 , 6 ). Disc moderately convex. Anterior margin straight or slightly concave in middle with anterior angles small but distinct, rounded, moderately protruded. Basal margin straight along internal 3/4, with laterobasal angles slightly shifted posteriad. Lateral margin convexly rounded in anterior 2/3 and concave towards laterobasal angles, latter large, rectangular or sharp at tip, sometimes slightly protruded laterally. Marginal gutter moderately broad throughout. Median longitudinal impression sharply incised, disappearing near apex, somewhat deepened before base. Anterior and posterior transverse impressions shallow and smooth. Laterobasal foveae large, internally and externally (towards lateral gutter) distinctly sloped, without punctures but with fine transversal wrinkles. Lateral and laterobasal setae present, with the former situated at or slightly anterad of maximum width of pronotum. Proepisternum glabrous and smooth.

Pterothorax: Elytra without pilosity, long and very slender ovate, very slightly convex or flattened in middle of disc, in dorsal view broadest distinctly posterad middle, shoulders flatly rounded (Fig. 13 ), apical sinuation distinct, apex rounded with the indication of a very obtuse apical angle. Striae 1-8 complete, moderately deep impressed, impunctate, intervals moderately convex, parascutellar stria free, 1/6-1/9 of length of elytra. Recurrent preapical stria deep, long, in most specimens reaching the apex of the fifth stria. Parascutellar seta present. Anterior discal seta located in the 4th interval, adjoined to the 4th stria, located near the end of the anterior elytral 5th (Fig. 13 ); second discal seta located at the 3rd stria about at elytral middle (in most specimens, the posterior setiferous pore together with the 3rd stria is switched into the 4th interval); posterior discal seta (= subapical seta near the end of 3rd stria) present, located about 1/9 of elytral length from elytral apex; subapical seta of the recurrent stria isolated, distinctly removed from this stria by distance of 2-3 diameters of the setiferous pore. Number and positions of the setae of the marginal umbilicate series as in Trechus s. str. Metepisternum very short, glabrous and smooth, with outer margin about as long as anterior margin.

Legs: Moderately long and robust. Protibia distinctly dilated towards apex, straight, with longitudinal groove on dorsal surface complete, and with several fine setae on anterior surface near apex (Fig. 12 ). Two basal protarsomeres of males dilated and dentoid at the inner apical border (Fig. 10 ). Fourth pro-, meso- and metatarsomeres each with a row of long adhesive hairs on apical margins which are as long as the 5th tarsomeres (Figs 10 , 11 ).

Male genitalia (Figs 14 , 15 ): Aedeagal median lobe markedly elongated, slender tube-like, in lateral view slightly sinusoidal, with apex distinctly bent upwardly, simple, with apical lamella insignificant; basal bulb rather small with large sagittal aileron. Endophallus with a small, very slightly sclerotized copulatory piece. Parameres with 3-4 apical setae.

Distribution.

So far only known from Mt. Choke in northern Ethiopia (Fig. 1 ).

Relationships and identification.

Based on the molecular data, Baehria gen. nov. is representative of a well-supported clade comprising Duvaliomimus Jeannel from New Zealand and Paratrechus Jeannel from South and Central America (Fig. 2 ). Apart from a general " Duvalius -like" appearance, the three genera share some common features like the large size, cordate pronotum, rounded head with salient temples, and pubescent protibiae. Baehria gen. nov. differs from both these genera by the presence of three or four setae instead of two on each side of the clypeus, and by the position of the anterior discal seta on elytra: in Baehria gen. nov., this seta inserts in the 4th interval instead on the 3rd stria in Duvaliomimus and on the 5th stria in Paratrechus . Baehria gen. nov. differs additionally from Paratrechus by the simple apex of the aedeagal median lobe, which is button-like shaped in Paratrechus ( Jeannel 1928; Barr 1982; Townsend 2010).

Figures

Figure 1. Map of Ethiopia showing the main topographic features of the country. Seven prominent volcanic massifs which are discussed in the text are highlighted. The base map was downloaded from www. freeworldmaps. net (01 - 07 - 2023).

Figure 2. Ultrametric time-calibrated phylogeny of Trechini beetles and outgroups (basal part of the tree, continues in Fig. 3). The tree was obtained from BEAST 2 based on the concatenated sequence data and using two age constraints (for details see text). Black circles and stars at branch nodes refer to posterior probabilities ≥ 0.98 and bootstrap values> 75, respectively. Grey bars specify the 95 % HPD of the respective node age. Collapsed, colored trechine clades refer to previous results of Faille et al. (2013). The southern hemisphere Duvaliomimus - Paratrechus clade with the Ethiopian endemic Baehria gen. nov. is highlighted ochre.

Figures 4 - 7. Baehria separata Schmidt & Faille, gen. nov., sp. nov., dorsal aspect of body (4, 6) and head (5, 7) of paratypes; 4, 5. Male; 6, 7. Female. The small white circles in Figs 5 and 7 mark the insertion points of the clypeal setae.

Figures 8 - 15. Baehria separata Schmidt & Faille, gen. nov., sp. nov. 8. Left and right mandible, dorsal aspect; 9. Ventral aspect of head; the small white circles mark the insertion points of the setae on submentum; 10. Right male protarsomeres, left latero-ventral aspect; 11. Left male metatarsomeres, right lateral aspect; 12. Right male protibia, dorsal aspect; 13. Anterior part of elytra and pronotal base; the arrows point to the insertions of the anterior elytral discal setae; 14. Aedeagus, left lateral aspect; 15. Aedeagus, dorsal aspect.