Orthogonius euthyphallus Tian & Deuve

Tian, Mingyi & Deuve, Thierry, 2013, Definition and review of the lancangjiang species group of the termitophilous genus Orthogonius Macleay, 1825 (Coleoptera, Carabidae, Orthogoniini), ZooKeys 349, pp. 81-100 : 86-88

Orthogonius euthyphallus Tian & Deuve sp. n. Figs 1, 4, 10-11, 14-15

Diagnosis.

Medium to large sized, slender and elongate; head longer than wide; upper surface covered with dense punctures; antennae long; eyes moderate in size; labrum broad at front margin; pronotum quite narrow, but transverse in form; whole lateral expanded margins slightly reflexed; elytra not carinate on interval 7 in both sexes.

Length: 14.0-16.0 mm; width: 5.5-6.5 mm. Habitus as in Fig. 4.

Description.

Body elongate, strongly shiny.

Head and disc of pronotum black; elytra dark brown or brown; lateral expanded margins of pronotum, antennomere 1 and 3, mandibles, and tibiae dark brown; palps, legs excluding tibiae and antennae brown.

Macrosculpture: Surface of head, pronotum and elytra with dense punctures, head obscurely striate, pronotum and elytra without wrinkles.

Microsculpture: Engraved meshes isodiametric on head and elytra, but moderate transverse on pronotum.

Head longer than wide, HL/HW=1.15-1.18, eyes rather small but prominent, frons and vertex convex, frontal impressions large and deep; clypeus bisetose, basal portion unevenly convex; labrum broad at front margin, sexsetose; palps rather stout, subcylindrical, maxillary palpomere 3 as long as 4, palpomere 4 glabrous, palpomere 3 with two short setae at apex; labial palpomere 2 slightly longer than 3, bisetose on inner margin, with several additional setae at subapex and apex, palpomere 3 bearing a few tiny setae; ligula small, bisetose at apex; mentum without tooth, each of mentum and submentum bisetose, palpiger asetose. Antennae very long, extending to the middle of elytra; pubescent and slightly expanded from basal 1/3 of antennomere 4; antennomrere 3 almost as long as 4, and 1.32 times longer than 2; antennomere 1 unisetoae on subapex.

Pronotum strongly transverse, PW/PL=1.55-1.63, disc moderately convex, fore and basal margins well beaded, sides evenly expanded, widest at about middle; lateral expanded margin well defined, flat and very smooth, slightly reflexed; both transversal impressions distinct, basal foveae small and deep; median line clear.

Elytra elongate ovate, EL/EW=1.71-1.82; widest at a little behind middle, sides slightly expanded at middle, basal border complete, apex broadly sinuate, inner angle nearly rectangular and obtuse; striae very deep, intervals strongly convex, subequal in width in middle, interval 3 with basal and middle setiferous pores, the subapical one absent.

Legs slender, fore tibia distinctly expanded at apex, apex obliquely truncate, outer margin slightly subserrate; middle and hind coxae smooth and glabrous; middle tibia strongly curve, slightly expanded at apex; hind tibia hardly expanded at apex, apical spurs long and sharp, hind tarsomere 3 much longer than 4, length ratio of tarsomeres 1-4 as 2.55, 1.79, 1.32 and 1.0; tarsomere 4 asymmetrically emarginated at apex, longer lobe as long as 1/3 of the whole joint; hind femur thin, slightly expanded medially, with two long setae posteriorly; tarsal claws strongly pectinate.

Prosternal process well bordered at apex, abdominal ventrite VII of male distinctly and deeply emarginate at apical margin.

Male genitalia (Figs 14-15): Slender and quite straight, slightly sinuate on ventral surface, apex blunt; the apical lamella as long as wide, broad at tip.

Remarks.

This new species differs from Orthogonius lancangjiang by the wider emargination on ventrite VII in males, which is gradually narrowed towards base (suddenly but somewhat obliquely narrowed towards base in Orthogonius lancangjiang ), the median lobe of aedeagus is less straight, more sinuate ventrally, and apex thin and broad (thick and obtuse at apex in Orthogonius lancangjiang ); and elytra with sparser punctures (densely punctate in Orthogonius lancangjiang ).

Material examined.

Holotype: male, "S. Vietnam, 28-30.4.1994, 12 km N. Dalat, Lang Bian, Pacholatko & Dembicky", "Mus. Wien", in NHMV.

Paratypes. 1 male, idem; 9 males and 3 females, "S. Vietnam, 17-21.4.1995, 12 km N. Dalat, Lang Bian", "12.03N108.27E, 1580-1750 m, Pacholatko & Dembicky", and "Mus. Wien", all in NHMV except 1 male and 1 female in SCAU.

Etymology.

The name of the new species is combined by the Greek prefix “euthy-”, meaning straight, and word “phallus”, meaning penis, to refer to the straight median lobe of aedeagus.

Distribution.

Southern Vietnam (Fig. 1).