Trechus iridescens Schmidt & Faille 2018, sp. nov.

Trechus iridescens sp. nov.

urn:lsid:zoobank.org:act: 3C59476B-17BA-4DAF-A3C8-FDC8B111D196

Figs 14, 18, 22, 45–46

Diagnosis

In external and male genital characters very similar to T. relictus from northeastern slope of Bale Mts, but colour of body darker, with elytra distinctly iridescent, pronotum more discoidal with lateral margin more markedly bent anteriorly, elytra broader with lateral margin more markedly convex, and aedeagal median lobe shorter with ventral margin not sinusoidal. For differentiation with the very similar T. oppositus sp. nov. from the western Bale Mts, see diagnosis of the latter species below.

Etymology

The specific epithet refers to the markedly iridescent elytra of the new species.

Material examined

Holotype

ETHIOPIA: ³, Oromia, Bale Mts, Mt Abalk–hasim, river vall., alt. 3250 m, 06°44′34″ N, 39°48′34″ E, Feb. 2007 (CSCHM, registration number ZSM _COL_ 2018 _006).

Paratype

ETHIOPIA: 2 ³³, 3 ♀♀, same data as for holotype (CAF, CSCHM).

Description

BODY LENGTH. 2.5–2.9 mm (Ø = 2.75 mm; n = 6).

PROPORTIONS (n = 6). PW/HW = 1.33–1.42 (Ø = 1.38); PW/PL = 1.39–1.45 (Ø = 1.42); PW/PBW = 1.22–1.27 (Ø = 1.25); EW/PW = 1.53–1.65 (Ø = 1.58); EL/EW = 1.27–1.38 (Ø = 1.30).

COLOUR. Head, pronotum and elytra blackish brown, very shiny, elytra markedly iridescent. Clypeus, labrum, palpi, antennal base and legs yellowish; antennae distally darkened beginning from second antennomere.

MICROSCULPTURE. Same in males and females. Head with comparatively large, almost isodiametric meshes on disc and supraorbital area, and smaller meshes on clypeus. Pronotum and elytra with slightly engraved narrow transverse meshes, which are much narrower and hardly visible on elytra.

HEAD. Comparatively robust. Mandibles short. Labrum with apical margin widely emarginated. Eyes small, distinctly convexly protruded. Tempora convex, markedly wrinkled to the neck, 1.1 times as long as eyes, very finely and sparsely pubescent. Frons and supraorbital area strongly convex, with supraorbital furrows almost uniformly bent on disc, deep throughout. Antennae short, proportions of the first four antennomeres as follows: 1/1/0.85/0.75; antennomeres 7–9 only slightly longer than broad.

PROTHORAX. Pronotum large, transverse, with lateral margin more markedly bent towards apex than to base and with broadest portion in or slightly before middle; base slightly broader than apical margin. Disc markedly convex. Anterior margin slightly concave with anterior angles rounded, slightly protruded. Sides rounded throughout but less markedly towards base. Laterobasal angles very obtuse, blunt at apex. Marginal gutter very narrow, slightly widened near laterobasal angles. Base slightly concave in middle, distinctly bent anteriorly at outer quarter. Median longitudinal impression fine but distinct, not deepened near base, disappearing at apex; anterior transverse impression indistinct, smooth; posterior transverse impression very shallow, laterobasal foveae diffuse limited towards disc and sides, moderately small, smooth. Pronotum with laterobasal setae present.

PTEROTHORAX. Elytra convex on disc, in dorsal view moderately short and broad, broadest in mid-length or slightly before, with shoulders fully rounded; broadly rounded at apex. Striae impunctate, parascutellar stria absent; all other striae hardly visible or absent apart from stria 8 which is slightly impressed from level of the middle or subapical groups of the marginal umbilicate pores towards apex. All intervals flat. Recurrent preapical stria deep, curved in front, directed to the fifth stria. Third stria with two setiferous dorsal pores, the anterior one between anterior elytral fifth and quarter, the posterior one in middle, and with preapical seta situated at the apical anastomosis of second and third striae, slightly closer to the elytral apex than to the suture. Number and positions of the setae of the marginal umbilicate series as in Trechus s. str.

LEGS. Short and comparatively thin; protibia slightly dilated towards apex, hardly bowed, finely but distinctly grooved on external surface. Only one basal protarsomere of male dilated.

MALE GENITALIA. EL/AL = 3.01–3.13 (Ø = 3.06, n = 3). Aedeagal median lobe moderately small, moderately slender, in lateral view almost evenly bent throughout; apical lamella moderately long with distinct button-like apical capitulum; basal bulb and sagittal aileron average. Endophallus with copulatory piece narrowly triangular, arcuate towards apex, in lateral view more strongly sclerotized on dorsal side.

Distribution

Known only from the type locality, along a brook valley near Mt Abalk-hasim, on southeastern slope of Bale Mts, at an altitude of 3250 m.