Trechus (Abyssinotus) yitbareki Schmidt, 2024

Schmidt, Joachim & Merene, Yeshitla, 2024, Trechus species from Mt. Choke of northern Ethiopia related to T. niloticus (Quéinnec & Ollivier) with notable male genital morphology (Carabidae: Trechini), Zootaxa 5492 (3), pp. 343-355 : 347-349

Trechus (Abyssinotus) yitbareki Schmidt , sp. n.

Fig. 2B , 3C, F, H

Type material. Holotype: ♂, with label data: Ethiopia, Amhara, W-slope Mt.Choke , 3370 m, 23.II.2019, 10°38‘07“N 37°45‘51“E, leg. D. Hauth, J. Schmidt, Yeshitla M., Yitbarek, W. ( CSCHM) . Paratypes: 33 ♂♂, 17 ♀♀, with same data as holotype ( NHMAA, ZSM, CAF, CSCHM) . 48 ♂♂, 31 ♀♀, W-slope Mt. Choke , 3450 m, 22.II.2019, 10°38‘09“N 37°46‘06“E, leg. D. Hauth, J. Schmidt, Yeshitla M., Yitbarek, W. ( NHMAA, ZSM, CSCHM) ; of these, 1 ♂ (DNA voucher SMNS-L1821 ) was used for molecular genetic study ( Faille et al. 2023).

Etymology. The new species is dedicated to one of its collectors, Yitbarek Woldehawariat, professor and entomologist at the Department of Zoological Science, University of Addis Ababa.

Description. Body length: 2.4–2.8 mm.

Proportions (n = 10): PW/HW = 1.39–1.47 (Ø = 1.43); PW/PL = 1.33–1.42 (Ø = 1.37); PW/PBW = 1.18–1.22 (Ø = 1.20); PBW/PAW = 1.21–1.29 (Ø = 1.24); EW/PW = 1.41–1.51 (Ø = 1.46); EL/EW = 1.28–1.35 (Ø = 1.31).

Colour: Head, pronotum and elytra blackish brown, pronotum sometimes more reddish; mandibles, palps, antennal base and legs yellowish brown; antennae darkened beginning from second or third antennomere; in most specimens 2 nd maxillary palpomere darkened.

Microsculpture: Sculpticells on frons and supraorbital area large, moderately impressed, almost isodiametric, on clypeus very finely impressed, slightly transverse. Sculpticells on pronotal disc moderately impressed, slightly transverse. Elytra with large and deeply impressed, almost isodiametric or somewhat irregularly formed sculpticells.

Head: Compound eyes rather small, moderately convex; tempora about 4/5 of length of eyes. In all other characters as described in T. apertus sp. n.

Pronotum: Pronotum large and transverse, sub-discoidal, broadest slightly before middle, with base distinctly broader than apex; disc moderately convex.Anterior margin slightly concave, with anterior angles slightly protruded anteriorly, rounded; basal margin convex, with laterobasal angles markedly shifted anteriorly; lateral margin almost evenly rounded throughout; laterobasal angles obtuse, sometimes indistinct. Marginal gutter narrow, extending towards laterobasal foveae, slightly widened between laterobasal angle and foveae. Median longitudinal impression finely incised, disappearing near apex and base; anterior transverse impression indistinct, smooth, posterior transverse impression broad and very shallow, smooth; laterobasal foveae small, moderately deep, smooth. Lateral and laterobasal setae present, with the former situated at the end of anterior pronotal third.

Pro- and mesothorax: Pro- and mesepisternum glabrous and smooth.

Pterothorax: Elytra short, ovate, with disc convex, in dorsal view broadest in middle, humerus rounded, subapical sinuation indistinct, apex rounded. Striae 1–3 slightly impressed, indistinct in some specimens, smooth or suggestively punctate, external striae absent apart from the apical portion of stria 8 which is distinctly deepened before apex; parascutellar stria absent. Recurrent preapical stria short, deep, with outer curvature directed towards the fifth stria. Parascutellar seta present; three discal setae located in the 3rd interval, adjoined to the 3rd stria: anterior seta located near the end of the anterior elytral 8th; middle seta located anterior of elytral middle, near the end of elytral 3/7; posterior seta (= subapical seta) located about 1/8 of elytral length from elytral apex; seta of the recurrent stria isolated, removed from this stria by distance of the diameter of the pore. Number and positions of the setae of the marginal umbilicate series as normal for Trechus s. l. Metepisternum very short, glabrous and smooth, with outer margin about as long as anterior margin.

Legs: Moderately short and robust. Protibia dilated towards apex, straight on external margin, its dorsal surface with longitudinal groove developed but very flat, without micro-setae on anterior surface. Two basal protarsomeres of males markedly dilated and dentoid at the inner apical border ( Fig. 3C ).

Male genitalia: EL/AL = 1.77–1.89 (Ø = 1.82; n = 8). Aedeagal median lobe robust, in lateral view markedly bent in basal half, almost straight towards apex, with moderately long apical lamella hook-like bent dorsally ( Fig. 3F ); in dorsal view with side margin almost parallel, very slightly widened in apical quarter and shortly narrowed towards slender apical lamella ( Fig. 3H ). Dorsal opening extends basally near to the apical margin of basal bulb. Sagittal aileron absent. Endophallus symmetrical in dorsal view, without a distinct copulatory piece, densely covered by tiny scales, in the inactive position with a sac-like folding structure near its base and an area covered by large sclerotized scales on its dorsal side ( Fig. 3F ). Parameres similar in size and shape, rather slender, each with four apical setae.

Differential diagnosis. Externally, T. yitbareki sp. n. is very similar to T. reebae , but differs in the proportionally longer median lobe of the aedeagus (EL/AL <1.9 in T. yitbareki sp. n.,> 2.0 in = T. reebae ) and in the longer apical lamella ( Fig. 3F ). The new species differs from the likewise similar T. igori sp. n. and T. kniphofia sp. n., prominently in the more markedly dilated protarsomeres 1 and 2 ( Fig. 3C ), and additionally in the more robust body which is, on an average larger, and in the larger aedeagus with longer apical lamella which is more markedly hook-like bent upwardly.

Distribution. Endemic to Mt. Choke in northern Ethiopia. The new species was only found near the top of a mountain ridge that extends from the crater rim to the west were it occurs sympatric with T. apertus sp. n. and T. igori sp. n. ( Fig. 4 ).

Habitat preferences. The new species was found syntopic with T. apertus sp. n.; see above for details of the habitat.

Figures

FIGURE 2. Habitus photographs of Trechus (Abyssinotus) species; the white circles point to the insertions of the supraorbital setae, pronotal lateral setae, parascutellar seta, elytral discal setae, and setae of the umbilicate series. A, T. reebae (Quéinnec & Ollivier, 2021), specimen from western crater valley. B, T. yitbareki Schmidt, sp. n., paratype. C, T. kniphofia Schmidt, sp. n., paratype. D, T. igori Schmidt, sp. n., paratype.

FIGURE 3. Left protarsomeres (A–C), aedeagus in left lateral view (D–G) and dorsal view (H–K) of Trechus (Abyssinotus) species. A, D, I, T. reebae (Quéinnec & Ollivier, 2021), specimen from western crater valley. B, E, J, T. kniphofia Schmidt, sp. n., paratype. C, F, H, T. yitbareki Schmidt, sp. n., paratype. G, K, T. igori Schmidt, sp. n., paratype.

FIGURE 4. Topographic map of Mt. Choke (highest point marked by a white triangle), showing sampling localities of six Trechus (Abyssinotus) species of the niloticus group (white circles; the numbers refer to the different species). 1, T. apertus Schmidt, sp. n. 2, T. reebae (Quéinnec & Ollivier). 3, T. yitbareki Schmidt, sp. n. 4, T. kniphofia Schmidt, sp. n. 5, T. igori Schmidt, sp. n. 6, T. niloticus (Quéinnec & Ollivier). Sampling data of T. reebae and T. niloticus published by Quéinnec et al. (2021) are considered. Base map was downloaded from Topographic-map.com.