Trechus minitrechus, 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 : 12-13

Trechus minitrechus sp. nov.

urn:lsid:zoobank.org:act:43FA1539-70DB-4B0E-947C-E48876836DA4

Figs 3 , 7 , 11 , 40, 41

Diagnosis

Given the overall similarity of T. minitrechus sp. nov. with T. gypaeti of the same volcanic mountain, these species are doubtless allopatric sister species. T. minitrechus sp. nov. is easily recognized from the latter by the lack of the posterior elytral dorsal seta. In addition, in the new species the copulatory piece of the aedeagus is distinctly more strongly sclerotized on the dorsal side than in T. gypaeti .

Etymology

The specific epithet refers to both the very small body length of the species, and to the species group Minitrechus, to which it belongs.

Material examined

Holotype

ETHIOPIA: ³, Oromia, Mt Enkuolo NE slope, alt. 3200–3300 m, 07°23′45″ N, 39°22′27″ E, 8 Dec. 2016 ( CSCHM, registration number ZSM _COL_2018_003).

Paratypes

ETHIOPIA: 19 ³³, 16 ♀♀, same data as for holotype ( CAF, CSCHM).

Description

BODY LENGTH. 2.4–2.6 mm (Ø = 2.52 mm, n = 20).

PROPORTIONS (n = 10). PW/HW = 1.25–1.34 (Ø = 1.31); PW/PL = 1.40–1.48 (Ø = 1.45); PW/PBW = 1.26–1.35 (Ø = 1.30); EW/PW = 1.48–1.60 (Ø = 1.54); EL/EW = 1.30–1.43 (Ø = 1.37).

COLOUR. Head, pronotum and elytra light brown, moderately shiny, not iridescent; clypeus, labrum, palpi, antennae, and legs yellowish.

MICROSCULPTURE. Same in males and females. Head with comparatively large, almost isodiametric meshes on disc and supraorbital area, and smaller meshes on clypeus. Pronotum with slightly smaller, slightly transverse meshes, which are more markedly engraved near base than on disc. Elytra with very narrow but distinct, transverse meshes.

HEAD. Comparatively robust. Mandibles short. Labrum with apical margin widely emarginated. Eyes markedly small and flat. Tempora convex, markedly wrinkled to the neck, 1.3–1.4 times as long as eyes, smooth or, in some specimens, with few very fine and very short hairs. 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: 1/1/0.9/0.75; antennomeres 7–9 only slightly longer than broad.

PROTHORAX. Pronotum moderately large, transverse, broadest portion distinctly before middle, base as wide as apical margin. Disc markedly convex. Anterior margin straight or very slightly concave with anterior angles rounded, not or very slightly protruded. Sides rounded in anterior ¾, +/- straight just anteriad of laterobasal angles; latter slightly obtuse, blunt at apex. Marginal gutter very narrow, slightly widened near laterobasal angles. Base straight in middle, distinctly bent anteriorly at outer quarter. Median longitudinal impression fine but distinct, not deepened near base, disappearing at apex; anterior transverse impression very shallow, smooth; posterior transverse impression shallow in middle, slightly deepened towards laterobasal foveae, latter very small, notch-like, smooth. Pronotum with laterobasal setae present.

PTEROTHORAX. Elytra convex on disc, in dorsal view moderately short and broad, broadest in midlength or slightly before, with shoulders fully rounded; broadly rounded at apex. Striae impunctate, parascutellar stria and first stria absent, latter sometimes finely impressed near apex, striae 2–5 indistinct but present, striae 6–7 usually absent, stria 8 moderately impressed from level of the middle group 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 a single setiferous dorsal pore near the end of anterior elytral quarter; preapical seta lacking. Number and positions of the setae of the marginal umbilicate series as in Trechus s. str. ( Fig. 11 ).

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 = 3.88–4.01 (Ø = 3.96, n = 6). Aedeagal median lobe small, moderately stout, in lateral view almost evenly bent towards apex; apical lamella very short with apex rounded; dimensions of basal bulb and sagittal aileron average. Endophallus with copulatory piece bag-like, triangular in lateral view, arcuate towards apex, very slightly sclerotized with exception of the dorsal side, which is covered with more strongly sclerotized scales.

Distribution

Known only from the type locality, along a brook valley on the northeastern slope of Mt Enkuolo, at altitudes of 3200–3300 m.

Figures

Figs 1–4. Trechus spp., habitus. 1. T. mattisi sp. nov., paratype, ³. 2. T. transversicollis sp. nov., holotype. 3. T. minitrechus sp. nov., paratype, ³. 4. T. nanulus sp. nov., paratype, ³.

Figs 5–8. Trechus spp., head, pronotum. 5. T. mattisi sp. nov., paratype, ³. 6. T. transversicollis sp. nov., holotype. 7. T. minitrechus sp. nov., paratype, ³. 8. T. nanulus sp. nov., paratype, ³.

Figs 9–12. Trechus spp., elytra. 9. T. mattisi sp. nov., paratype, ³. 10. T. transversicollis sp. nov., holotype. 11. T. minitrechus sp. nov., paratype, ³. 12. T. nanulus sp. nov., paratype, ³. The arrows point to the insertions of the discal setae, preapical seta (if present), and setae of the umbilical series.

Figs 37–56. Trechus spp., aedeagal median lobe, left lateral view (37, 39, 40, 42, 44–45, 47–48, 50, 52–53, 55–56) and dorsal view (38, 41, 43, 46, 49, 51, 54). 37–38. T. mattisi sp. nov., paratype. 39. T. transversicollis sp. nov., holotype. 40–41. T. minitrechus sp. nov., paratype. 42–43. T. nanulus sp. nov., paratype. 44. T. rira sp. nov., holotype. 45–46. T. iridescens sp. nov., holotype. 47. T. relictus Magrini, Quéinnec & Vigna Taglianti, 2012, specimen from brook valley above Goba. 48–49. T. oppositus sp. nov., paratype. 50–51. T. harryi sp. nov., paratype. 52. T. dodola sp. nov., holotype. 53–54. T. adaba sp. nov., paratype. 55. T. harenna sp. nov., paratype. 56. T. bombi sp. nov., holotype.