Trechus mekbibi, Schmidt & Faille, 2018

Schmidt, Joachim & Faille, Arnaud, 2018, Revision of Trechus Clairville, 1806 of the Bale Mountains and adjacent volcanos, Ethiopia (Coleoptera, Carabidae, Trechini), European Journal of Taxonomy 446, pp. 1-82 : 35-37

Trechus mekbibi sp. nov.

urn:lsid:zoobank.org:act:E5D250CA-25F7-406D-90B0-E40FF9299CF1

Figs 68 , 72 , 76 , 116–117

Diagnosis

Within the fauna of the study area this species is easy to distinguish from all other Trechus species by the combination of the following characters: eyes large; pronotal laterobasal angles very large, acute, distinctly protruded lateriad and posteriad; two basal protarsomeres of male dilated. A very marked similarity of the male genital characters of T. mekbibi sp. nov. is observed with T. hagenia sp. nov.; for differentiation see Identification chapter of the latter species below.

Etymology

This very characteristic new species is dedicated to Mr. Mekbib Fekadu, Addis Ababa and Marburg, expert of mountain and plant ecology of Ethiopia, for his long-standing help and support given to the research teams on the Bale Mts biogeography.

Material examined

Holotype

ETHIOPIA: ³, Oromia, Bale Mts, road N Rira, Ericaceous forest , alt. 3000–3200 m, 06°46′ N 39°44′ E, 28 Feb. 2013 ( CSCHM, registration number ZSM _COL_2018_014).

Paratypes

ETHIOPIA: 57 specimens (³³, ♀♀), same data as for holotype ( CAF, CSCHM); 55 specimens (³³, ♀♀), S slope Bale Mts, Rira Vall., alt. 3130 m, 06°46′36″ N, 39°44′18″ E, 1 Mar. 2015 ( CSCHM); 106 specimens (³³, ♀♀), S slope Bale Mts, Rira Vall., alt. 3230 m, 06°46′30″ N, 39°44′41″ E, 1 Mar. 2015 ( CSCHM); 141 specimens (³³, ♀♀), S slope Bale Mts, above Rira, alt. 3150–3250 m, 06°46′30″ N, 39°44′31″ E, Dec. 2006 ( CAF, CSCHM); 1 ♀, Bale Berge, Harenna Forest, near Gora, alt. 2800 m, 6.8112° N, 39.5751° E, 7 Dec. 2012 ( CIH); 54 specimens (³³, ♀♀), western Bale Mts, above Dodola, alt. 2700–2850 m, 06°53′49″ N, 39°11′32″ E, Dec. 2006 ( CAF, CSCHM); 1 ³, 2 ♀♀, same data as for preceding but alt. 3400–3700 m, 06°51′ N, 39°14′ E, Dec. 2006 ( CAF, CSCHM); 64 specimens (³³, ♀♀), Bale Mts, south of Adaba, alt. 3170 m, 06°49′31″ N, 39°25′37″ E, Feb. 2007 ( CAF, CSCHM); 2 ³³, 5 ♀♀, Bale Mts, near pass south of Adaba, alt. 3250 m, 06°46′33″ N, 39°24′58″ E, 22 Feb. 2017 ( CAF, CSCHM); 4 ³³, 4 ♀♀, Harenna Forest, W Rira, alt. 3000 m, 06°45′57″ N, 39°41′47″ E, 14 Dec. 2017 ( CAF, CSCHM); same data as for preceding but alt. 2750 m, 06°45′40″ N, 39°42′23″ E, ( CAF); 10 ³³, 8 ♀♀, Bale Mts, S slope above Rira, alt. 3240 m, 06°46′39″ N, 39°44′52″ E, 15 Dec. 2017 ( NHMUK, CDH, MNHN, ZMAA).

Description

BODY LENGTH. 4.2–4.8 mm (Ø = 4.45 mm, n = 20).

PROPORTIONS (n = 10). PW/HW = 1.48–1.53 (Ø = 1.51); PW/PL = 1.46–1.53 (Ø = 1.49); PW/PBW = 1.20–1.29 (Ø = 1.25); EW/PW = 1.39–1.45 (Ø = 1.43); EL/EW = 1.31–1.36 (Ø = 1.34).

COLOUR. Head, pronotum, and elytra blackish brown, markedly shiny, elytra iridescent. Labrum, palpi, antennal base, elytral margin and apex, and legs light brown; antennae distally darkened beginning from the second third of the third antennomere.

MICROSCULPTURE. Same in males and females. Head with rather large, almost isodiametric meshes on disc and supraorbital area, and smaller meshes on clypeus. Pronotum with moderately large, somewhat irregularly formed or slightly transverse meshes. Elytra with hardly visible, very slightly engraved, very narrow transverse meshes.

HEAD. Size normal for Trechus . Mandibles moderately short. Labrum with apical margin widely emarginated. Eyes large, convexly protruded. Tempora moderately short, convex, markedly wrinkled to the neck, 0.35–0.37 times as long as eyes, smooth. Frons and supraorbital area strongly convex, with supraorbital furrows almost uniformly bent on disc, deep throughout. Antennae moderately slender, proportions of the first four antennomeres as follows: 1/0.7/0.9/0.8.

PROTHORAX. Pronotum large, transverse, broadest portion slightly before middle, base distinctly wider than apical margin. Disc moderately convex. Anterior margin concave with anterior angles slightly protruded, rounded. Sides convexly rounded in anterior ¾, concave before base. Laterobasal angles large, acute, distinctly laterally protruded. Marginal gutter moderately narrow, distinctly widened near laterobasal angles. Base straight in middle, distinctly bent posteriorly at outer quarter. Median longitudinal impression distinct, slightly deepened near base, disappearing at apex; anterior transverse impression indistinct, smooth; posterior transverse impression very shallow; laterobasal foveae moderately large, rather shallow, smooth, bordered from the lateral gutter by a slightly elevated area. Pronotum with laterobasal setae present.

PTEROTHORAX. Elytra markedly convex on disc, in dorsal view broad oval, broadest in mid-length, with shoulders markedly broad, shortly rounded towards base; apex suggestively pointed. Striae impunctate or suggestively punctate, parascutellar stria moderately short, deep, striae 1–2 (3) moderately impressed, external striae finer, 6–7 usually absent, 8 deeply impressed from level of the middle group of the marginal umbilicate pores towards apex. Intervals flat or internal 1–3 intervals very slightly convex. Recurrent preapical stria deep, short, slightly curved in front, directed to the seventh stria. Third stria with two setiferous dorsal pores, the anterior one near the end of the anterior elytral quarter, the posterior one in middle, and with preapical seta which is situated at the apical anastomosis of second and third striae almost as close to the elytral apex as to the suture. Number and positions of the setae of the marginal umbilicate series as in Trechus s. str.

LEGS. Moderately short and comparatively thin; protibia slightly dilated towards apex, almost straight, distinctly grooved on external surface. Two basal protarsomeres of male dilated.

MALE GENITALIA. EL/AL = 2.50–2.68 (Ø = 2.56, n = 8). Aedeagal median lobe elongated, in lateral view with ventral margin slightly bent behind basal bulb, slightly convex in middle, slightly sinuate towards apex, longitudinally keel-like reinforced (keel bar visible in both ventral and dorsal views as a straight dark longitudinal strip); apical lamella rather short with hook-like apex bent upward; basal bulb rather small with sagittal aileron rather large. Dorsal surface of median lobe more strongly sclerotized in anterior quarter (just below apical ostium), forming an elongate bowl for the endophallic copulatory piece; latter in lateral view spine-like, slightly curved, in dorsal view dagger-like with broad base.

Distribution

From the Rira Valley, on the southern escarpment of the Bale Mts to the western part of the Bale Mts near the city of Dodola; not on the eastern and northeastern slopes of the massif. The species was found at altitudes of 2700–3400 m.

Figures

Figs 67–70. Trechus spp., habitus. 67. T. depressipennis sp. nov., holotype. 68. T. mekbibi sp. nov., paratype, ³. 69. T. hagenia sp. nov., paratype, ³. 70. T. colobus sp. nov., paratype, ³.

Figs 71–74. Trechus spp., head, pronotum. 71. T. depressipennis sp. nov., holotype. 72. T. mekbibi sp. nov., paratype, ³. 73. T. hagenia sp. nov., paratype, ³. 74. T. colobus sp. nov., paratype, ³.

Figs 75–78. Trechus spp., elytra. 75. T. depressipennis sp. nov., holotype. 76. T. mekbibi sp. nov., paratype, ³. 77. T. hagenia sp. nov., paratype, ³. 78. T. colobus sp. nov., paratype, ³. The arrows point to the insertions of the discal setae and the preapical seta (if present).

Figs 115–125. Trechus spp., aedeagal median lobe, left lateral view (115–116, 118, 120, 122, 124–125) and dorsal view (117, 119, 121, 123). 115. T. depressipennis sp. nov., holotype. 116–117. T. mekbibi sp. nov., paratypes. 118–119. T. hagenia sp. nov., paratypes. 120–121. T. colobus sp. nov., paratypes. 122–123. T. wiersbowskyi sp. nov., paratypes. 124. T. haggei sp. nov., paratype. 125. T. grandipennis sp. nov., holotype.