Oxytrechus osellai, Giachino, Pier Mauro, Allegro, Gianni & Baviera, Cosimo, 2014

Giachino, Pier Mauro, Allegro, Gianni & Baviera, Cosimo, 2014, Two new species of Oxytrechus Jeannel, 1927 from Ecuador (Coleoptera, Carabidae), Zootaxa 3895 (1), pp. 144-150 : 145-148

Oxytrechus osellai sp. n.

( Figs. 1–2 )

Type locality. Ecuador, Pichincha, Cangahua, m 3375, 0°10.607 S 78°7.203 W.

Diagnosis. An Oxytrechus species 2.48–2.62 mm long, black, shiny, with antennae and legs rufo-testaceous (fig. 1).

Oxytrechus osellai n. sp. is externally similar to O. onorei Allegro, Giachino & Sciaky, 2008 due to its small size and shape of the body, but is well characterized within the genus according to the peculiar shape of the median lobe of aedeagus, which shows, in lateral view, an apex obliquely truncated in the ventral-dorsal direction (fig. 2). Type series. HT ♂, Ecuador, Pichincha, Cangahua, m 3375, 0°10’607’’ S 78°7’ 203’’ W, vaglio paramo alto, 3.VIII.2008, legg. Baviera, Bellò, Osella & Pogliano (CGi).

PTT: 7 ♂♂ 5 ♀♀, same data as the holotype (CAl, CBa, CGi, QCAZ); 1 ♂, Ecuador, Pichincha, P.N. Cayambe, m 3050, S 0°2’ 739’’ W 78°5’57’’, vaglio bosque nublado, legg. Baviera, Bellò, Osella & Pogliano (CGi); 2 ♂♂, Ecuador - Pichincha - Cangahua, 3775 m, 3.VIII.2008 (NW Oyacachi), Baviera, Bellò, Osella & Pogliano (Coll. Osella) S 0° 10’ 607 / W 78° 7’ 203, vaglio paramo alto, legg. Baviera, Bellò, Osella & Pogliano (CMo).

Description.Total length (from apical margin of labrum to tip of elytra): mm 2.48–2.51 ♂♂, 2.52–2.62 ♀♀. Micropterous; black, with legs, mandibles, palpi and antennae rufo-testaceous. Teguments smooth, shiny, glabrous, with microsculpture hardly visible on disk of pronotum and elytra, more evident on elytra, consisting of very thin transversal meshes.

Head small and elongated; temples long (as long as the eyes), prominent and narrowing on neck; frontal furrows deep and complete; eyes not very large and flat, markedly longer than genae; two supraorbital setae on each side and on lines not converging backwards. Antennae narrow and short, hardly reaching the elytral base, with the apical segment slightly longer than penultimate.

Pronotum strongly transverse (PW/PL = 1.27–1.37 ♂♂; 1.30–1.40 ♀♀), convex, largest at the anterior fourth. Sides arcuate throughout their length, sinuate before the hind angles, which are obtuse but prominent; front angles not projecting forwards; basal peduncle prominent, not bordered at the posterior edge; lateral keel relatively narrow; median furrow superficial; basal impressions small and superficial, adjoining the terminal part of the lateral keel. Two lateral setae on each side, the anterior one just before the largest point, the posterior markedly advanced with respect to basal angle.

Elytra oval, moderately slender, convex; lateral keel broad, flattened, with salient and almost reflex borders; shoulders regularly rounded, not angulate, not prominent; external elytral striae completely obsolete, striae 1–3 hardly visible in the basal part, completely obsolete in the apical one; sutural stria hardly visible. Basal striole absent, recurrent stria and apical carina scarcely evident. Chaetotaxy: juxtascutellar pore present, two discal pores relatively large, fovea-like, the first one at basal fifth, the second one just after the middle; umbilicate series regular, humeral group with the pores 2nd to 4th almost equidistant,1st and 2nd closer; apical group with the anterior pore at the level of the 8th pore of the umbilicate series; exterior pore of the apical group lacking.

Legs short and slender; protibial furrow complete but superficial; metatibiae straight; in ♂ two first protarsomeres asymmetrically dilated.

Aedeagus (fig. 2) robust, elongate. Median lobe, in lateral view, markedly and sharply curved at base, subrectilinear in the central part, bent upwards in the apical one, which is subtriangular. Basal bulb normal, sagittal carina long and well developed. Inner sac provided with a long scaly patch. Styles long, reaching the apical third of the median lobe, each provided with 4 long distal setae.

Etymology. It is a pleasure for us to dedicate this new species to one of its collectors, our friend and colleague Giuseppe Osella, a specialist of Coleoptera Curculionoidea , as a token of our esteem for his valuable contribution to the knowledge of the South-American beetles.

Distribution and ecology. At present O. osellai n. sp. is only known from the type locality, Cangahua ( Ecuador, Pichincha province), where it was collected by sifting the soil collected under stones and bunch- or tussock-forming grasses typically occurring in the grass-páramos of Ecuador from about 3400 to over 4000 m ( Moret, 2009) (fig. 8).

Figures

FIGURES 1 – 4. Habitus (1, 3) and aedeagus (2, 4) of: O. osellai n. sp. HT ♂ (1, 2) and O. belloi n. sp. HT ♂ (3, 4).