Trechisibus longipenis, Allegro, Gianni & Giachino, Pier Mauro, 2016

Allegro, Gianni & Giachino, Pier Mauro, 2016, Nine new Trechisibus species from Peru and Argentina (Coleoptera: Carabidae: Trechinae), Zootaxa 4193 (1), pp. 49-72 : 66-68

Trechisibus longipenis n. sp.

( Figs. 11 a, 11b, 11c, 11d, 20)

Type locality. Argentina, Neuquen, Pen. Quetrihué.

Diagnosis. A Trechisibus species 3.37–3.73 mm long, dark brown and shiny; legs, mouth parts and lateral border of elytra reddish brown; antennae slightly darkened from 3rd–4th antennomeres. Hind angles of pronotum acute and protruding backwards and outwards. Elytra oval, widest at middle, moderately depressed on disc, with 2 discal setigerous punctures (in addition to the preapical pore) on the 3rd stria, the first at about 1/6 from base and the second just before middle. T. longipenis n. sp. is distinguished from all other Trechisibus species distributed in southern Andes by the peculiar morphology of the median lobe of the aedeagus, which is extraordinarily long and slender ( Fig. 11 b).

Type series. HT ♂, Argentina, Neuquen, Pen. Quetrihué, 12.II.1998, legit Riccardo Sciaky (CSc). PTT: 2 ♂♂ 1 ♀, same data as the holotype (CAl, CGi, CSc).

Description. Habitus as in Fig. 11 a. Overall length of the HT ♂ (from labrum to apex of elytra) 3.68 mm (PTT ♂♂ 3.37–3.73, ♀ 3.68 mm). Body dark brown, obovate, shiny. Microsculpture markedly impressed on head, very superficial on pronotum and nearly absent on elytra. Legs, mouth parts, and lateral border of elytra reddish brown; antennae slightly darkened from 3rd–4th antennomeres. Brachypterous.

Head moderately large, eyes small and convex; temples convex and delicately pubescent, hardly longer than eyes. Microsculpture in isodiametric meshes markedly impressed on whole upper surface of head. Clypeus with two apical setae on each side; labrum transverse, 6-setose, distinctly excavate at apex. Frons between eyes convex, depressed on vertex. Antennae moderately long, hardly reaching the basal 4th of elytra.

Pronotum convex on disc, transverse (width/length = 1.31), with base as wide as anterior margin ( Fig. 20 ). Microsculpture very superficial, nearly absent on disc and more visible near base and fore margin. Sides rounded for most of length, shortly sinuate before hind angles; basal margin sinuate at sides. Front angles feebly prominent; hind angles acute and protruding backwards and outwards. Mid longitudinal line distinctly impressed between the submarginal sulci, deepened towards base. A wide basal impression on each side, separated at middle by the wrinkled mid convexity of the base. Lateral border moderately wide on whole length; anterior margin unbordered, the posterior bordered only at sides. Two lateral setae on each side, one at hind angles (moved a little forwards from the angle) and one at about 2/3 from base.

Elytra oval (length/width=1.35), widest at middle, feebly depressed on disc. Microsculpture in transverse meshes, very superficial, nearly absent on disc and hardly visible near base and apex. Shoulders rounded with humeral angle indistinct. The basal margin interrupted in correspondence with the 5th interval. A short scutellar stria is present, as well as a juxtascutellar pore near base, in correspondence with the 2nd stria. Sides moderately rounded; lateral border wider in the basal half, reddish brown and distinctly contrasting in colour with the darker elytra. Two discal setigerous punctures in small and superficial foveae on the 3rd stria, the 1st at basal 6th of elytra and the 2nd just before middle; the punctures divert the 3rd stria linearity; preapical pore at about middle of the recurrent striole. Umbilicate series of 4+2+2 punctures, with groups widely spaced from each other. The five inner striae distinctly impressed, the others obliterated; the 8th stria deeply impressed in the posterior half. Intervals nearly flat. Elytral apex broad and rounded. The recurrent striola moderately long and arcuate.

Legs slender. Protibiae nearly straight and externally distinctly furrowed. Tarsi pubescent on the upper side. The 1st and 2nd male protarsomeres asymmetrically dilated.

Median lobe of aedeagus extraordinarily slender, in lateral view tapered and bent upward towards apex ( Fig. 11 b); apical blade long and, in dorsal view, spoon shaped and rounded at extreme apex ( Fig. 11 c). The internal armature is made by a copulatory piece long and thin, wides at base ( Figs. 11 b, 11c). Parameres long and slender, almost equally long, each provided with 4 apical setae ( Fig. 11 b).

Etymology. The specific epithet refers to the unusual slenderness of the aedeagus.

Distribution and habitat. At present Trechisibus longipenis n. sp. is only recorded from the type locality. The specimens of the type series were collected at about 800 m a.s.l.

Relationships. At the present state of knowledge, the phylogenetic affinities of Trechisibus brevis n. sp. are unclear, but despite the strong differences in the morphology of aedeagus, this species shares many external morphological features with Trechisibus striatus n. sp., Trechisibus sciakyi n. sp. and Trechisibus brevis n. sp.

Figures

FIGURE 11. Trechisibus longipenis n. sp. HT: habitus (a); median lobe of aedeagus in lateral view (b); median lobe of aedeagus in dorsal view (c).

FIGURES 17 – 21. Pronotum of Trechisibus: striatus n. sp. HT (17); sciakyi n. sp. HT (18); brevis n. sp. HT (19); longipenis n. sp. HT (20); parvulus n. sp. HT (21).