Trechus (Abyssinotus) igori 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 : 350-352

Trechus (Abyssinotus) igori Schmidt , sp. n.

Fig. 2D , 3G, K

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: 8 ♂♂, 7 ♀♀, with same data as holotype ( CSCHM) .

Etymology. The new species is dedicated to my dear friend and colleague, the distinguished carabidologist and explorer of the high altitude environments, Igor A. Belousov, St. Petersburg.

Description. Body length: 2.2–2.3 mm.

Proportions (n = 10): PW/HW = 1.31–1.41 (Ø = 1.36); PW/PL = 1.41–1.50 (Ø = 1.44); PW/PBW = 1.23–1.30 (Ø = 1.27); PBW/PAW = 1.07–1.12 (Ø = 1.10); EW/PW = 1.44–1.53 (Ø = 1.50); EL/EW = 1.30–1.35 (Ø = 1.32).

Colour: Head capsule, pronotum and elytra dark brown, pronotum paler in some specimens; clypeus, labrum, mandibles, palps, antennae and legs yellowish brown.

Microsculpture: Sculpticells on frons and supraorbital area large, moderately impressed, almost isodiametric, slightly transverse on clypeus. Sculpticells on pronotal disc and elytra moderately impressed, transverse.

Head: As described in T. yitbareki sp. n.

Prothorax: Pronotum moderately large, transverse, sub-discoidal, with base slightly more markedly narrowed towards base than in the proceeding species. In all other characters as described in T. yitbareki sp. n.

Pterothorax: First stria absent in anterior 2/3, suggestively impressed before its apex, striae 2 and 3 very finely impressed, indistinct, external striae absent apart from the apical portion of stria 8. In all other characters as described in T. yitbareki sp. n.

Legs: As in T. kniphofia sp. n.

Male genitalia: EL/AL = 2.20–2.30 (Ø = 2.24; n = 8). Aedeagal median lobe moderately robust, rather stout, in lateral view evenly curved throughout, with apical lamella very short, very slightly sclerotized, very shortly bent upwardly ( Fig. 3G ). Median lobe in dorsal view with side margins almost parallel, shortly narrowed towards apical lamella ( Fig. 3K ). Dorsal opening extends basally near to the apical margin of basal bulb. Sagittal aileron absent. Endophallus as described in T. kniphofia sp. n. Parameres similar in size and shape, slender, each with 3–4 apical setae.

Differential diagnosis. On average, T. igori sp. n. is the smallest species of the T. reebae group. It differs from all other species of the group by the transverse pattern of elytral microsculpture (isodiametric or somewhat irregularly shaped in the other species) and the very slightly sclerotized apex of the aedeagal median lobe. It additionally differs from T. niloticus , T. reebae and T. yitbareki sp. n. in the less markedly dilated basal protarsomeres in the male sex. Due to its small body length and shallower elytral striae, T. igori sp. n. is similar to T. abyssinicus and T. afroalpinus , however, it is easily distinguished by two basal protarsomeres dilated in males (one in the latter species).

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. yitbareki sp. n. ( Fig. 4 ).

Habitat preferences. The new species was found syntopic with T. apertus sp. n. and T. yitbareki 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.