Trechisibus curtii, 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 : 56-58

Trechisibus curtii n. sp.

( Figs. 6 a, 6b, 6c, 15)

Type locality. Peru, Huánuco, Quebrada Queulacocha , 3,800 m.

Diagnosis. A Trechisibus species 3.59 mm long, piceous black, moderately shiny; legs, antennae and mouth parts brown. Hind angles of pronotum acute and protruding outwards. Elytra oval, not depressed on disc, with four discal setigerous punctures (in addition to the preapical pore), the 1st–3rd on the 3rd stria and the 4th in the 3th interval, more or less regularly spaced; moreover, a single setigerous puncture is also present on the 5th stria, at about 1/4 from base (moved a little forwards with respect to the 2nd puncture of the 3rd stria). T. curtii n. sp. is easily distinguished from all other already known Trechisibus species by its peculiar elytral chaetotaxy: by comparison, the only other species showing a single setigerous pore on the 5th stria is Trechisibus hornensis (Fairmaire, 1885) , but it only shows 2 discal pores on the 3rd.

Type Series. HT ♂, Peru, Dept. Huánuco, Quebrada Queulacocha , m 3,800, VI.1981, legit M. Curti (CAl).

Description. Habitus as in Fig. 6 a. Overall length of the HT ♂ (from labrum to apex of elytra) 3.59 mm. Body piceous black, obovate, moderately shiny. Microsculpture in transverse meshes superficially impressed on elytra, more distinct near base of pronotum and on head; disc of pronotum smooth and shiny. Antennae, legs, clypeus and labrum dark brown, tarsi and palpi lighter. Brachypterous.

Head large with respect to pronotum, eyes large and convex; temples convex and delicately pubescent, a little shorter than eyes. Microsculpture superficially impressed on vertex, but very marked (almost wrinkled) towards eyes, laterally to frontal impressions, which are arcuate and deep. Clypeus with two apical setae in a deep depression on each side; labrum transverse, 6-setose, distinctly excavate at apex. Frons between eyes convex. Antennae short, hardly reaching the base of elytra.

Pronotum moderately convex on disc, transverse (width/length = 1.34), with base hardly wider than anterior margin ( Fig. 15 ). Disc shiny without any apparent microsculpture, which is distinct only near base. Sides rounded in the fore half and subrectilinear in the basal half, shortly but markedly sinuate before base; basal margin rectilinear. Front angles not prominent; hind angles acute and protruding outwards. Mid longitudinal line distinctly impressed between the submarginal sulci. Lateral margins wide and broadened towards base; anterior and posterior margins bordered only at sides. Two lateral setae on each side, one at hind angles and one at about 3/4 from base.

Elytra oval (length/width=1.41), fairly convex and not depressed on disc. Microsculpture in transverse meshes, superficial in both sexes. 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 junction of the 1st and 2nd stria. Sides moderately rounded; lateral border narrow but broader at base. Four setigerous punctures in small foveae, the 1st–3rd on the 3rd stria and the 4th in the 3th interval, more or less regularly spaced; a single setigerous puncture is also present on the 5th stria, at about 1/4 from base (moved slightly forwards with respect to the 2nd puncture of the 3rd stria); preapical pore at about middle of the recurrent striole. Umbilicate series of 3+2+2 punctures, with the groups widely distanced from each other. Striae 1st–4th very superficial and hardly visible, the others obliterated. Intervals flat. Elytral apex broad and rounded. The recurrent striola long and arcuate, with a remarkable apical carina.

Legs short. Protibiae delicately arcuate towards apex and externally superficially furrowed. Tarsi pubescent on the upper side. The 1st and 2nd male protarsomeres asymmetrically dilated.

Median lobe of aedeagus slender, obliquely inserted on the basal bulb ( Fig. 6 b), in lateral view the inferior edge nearly straight; in dorsal view, the median lobe is slender and parallel-sided, with apex short and broadly rounded ( Fig. 6 c). The internal armature is made by a hardly sclerotized copulatory piece ( Fig. 6 b). Parameres narrow and long, the left one longer than the right and as long as half of the median lobe, each provided with 3–4 apical setae ( Fig. 6 b).

Etymology. This species is dedicated to its collector, Marc Curti, a talented French amateur entomologist, as a token of our esteem.

Distribution and habitat. At present Trechisibus curtii n. sp. is only recorded from the type locality. The unique specimen of the type series was collected at 3,800 meters a.s.l., presumably in an Andean grassland habitat.

Relationships. Trechisibus curtii n. sp. does not show evident affinities with any other known Trechisibus species, and therefore is not yet included in any species group.

Figures

FIGURE 6. Trechisibus curtii n. sp. HT: habitus (a); median lobe of aedeagus in lateral view (b); median lobe of aedeagus in dorsal view (c).

FIGURES 13 – 16. Pronotum of Trechisibus: huascarani n. sp. HT (13); recuayi n. sp. HT (14); curtii n. sp. HT (15); lemairei n. sp. HT (16).