Onthophagus abmisibilus, Krikken, Jan & Huijbregts, Johannes, 2012

Krikken, Jan & Huijbregts, Johannes, 2012, Taxonomy of new relatives of Onthophagus catenatus Lansberge, 1883 from New Guinea (Coleoptera, Scarabaeidae, Scarabaeinae), ZooKeys 251, pp. 49-67 : 53-56

Onthophagus abmisibilus sp. n. Figs 1-212, 1722-26

Type-material.

Holotype, male: (RMNH), Indonesia,: West New Guinea, Papua, Star Mountains, Abmisibil, 1900-2200 m, 4°38'S, 140°33'E, 29. i– 09.ii.2005, T. Lackner. Locality description with landscape pictures: http://www.papua-insects.nl/about%20Papua/Starmountains/Star%20Mountains.htm (accessed 30.iii.2012).

Diagnosis.

Male of this species has two very distinctive features: the concave (in axial view), non-angulate crest of the plate connecting the bases of the vertexal horns, and the rather flat, faintly metallic anterior declivity of the pronotum. Dorsum black-brown, largely matt (particularly elytra). Elytral strial punctures all distinct, fine, equal-sized, and only slightly crenulating interstriae. Lateral border of pronotum distinctly rounded at some distance from anterolateral angle. Pronotum with widely bisinuate, blunt crest behind anterior declivity. Clypeofrontal ridge low, almost straight, on either end angularly connected at clypeogenal ridge. Most of dorsal side finely to minutely, sparsely punctate. Clypeal tip broadly, slightly reflexed, apical border bisinuate. Dorsal eye parts broadly elliptic, separated by slightly over three eye-widths. Pygidium abundantly, finely, distinctly punctate. Body length ca 11.5 mm, Onthophagus catenatus being smaller, 8-10 mm.

Description

(holotype, male). Body length ca 11.5 mm. Habitus generally convex, robust. Colour of dorsal side black, generally matt (microreticulate), with slight metallic lustre; ventral parts largely black, partly matt (microreticulate); legs black-brown, shiny. Dorsal side and pygidium virtually glabrous (apart from any inconspicuous micro-stubbles); ventral side and legs with numerous long, light-brown setae.

Head shiny, sparsely micropunctate throughout. Clypeal border broadly, distinctly marginate, sides very slightly rounded (almost straight) from genae to apex, the latter bisinuate, slightly reflexed, shortly lobiform; clypeogenal transition at border very obtusely angular, on either side with almost straight ridge extending past end of very weakly curved, distinct clypeofrontal ridge onto frontal side. Genal border evenly, widely rounded. Vertex between posterior end of eyes with pair of long, basally broad horns, connected at base by transverse, slightly concave, laterally sinuate (plate-like) elevation (in axial view); horns widely, evenly arcuate upward, directed laterad, over and beyond eyes (in axial view), evenly tapering to blunt tip; distal section of horn rounded on all sides. Frontal disc limited by fine frontogenal ridge, on either side extending along eye. Dorsal eye parts widely elliptic, with ca 28 facet rows across widest point. Ratio of interocular distance to maximum (transverse) eye width ca 3.3.

Pronotum generally strongly convex, surface matt, with cupreous lustre; disc posteriorly slightly convex (midline impression almost effaced), anterior declivity broadly deplanate, posterior rim slightly transversely arcuate-sinuate, blunt; anterior and lateral borders of pronotum marginate; anterior section of lateral border slightly concave; anterolateral angle rectangular, shortly rounded; posterior section of lateral border slightly sinuate, posterolateral angle rounded; base finely marginate, with very obtuse basomedian angle. Most of pronotal disc and medial surface in general sparsely micropunctate; lateral declivities with larger, but fine, more abundant punctation (surface microreticulate).

Elytra generally black, virtually matt (microreticulate); scutellum indistinct in dorsal view, shape of base and apex unmodified; anterior half of epipleuron distinctly punctate-setose. Elytra broad, with 8 straight to slightly curved, fine, distinct striae; stria 7 slightly sinuate in front, extending onto shining humeral umbone; striae fine, punctures fine but distinct, widely separated (mostly 4-8 puncture diameters), slightly crenulating interstrial edges. Interstrial surfaces virtually flat to slightly convex (from disc to lateral declivity of elytra), with sparse, inconspicuous micropunctation.

Antennal club medium-brown, scapus unmodified. Mentum shallowly emarginate in front. Prothoracic sides with coxal-marginal ridge distinct, curving forward onto lateral border, much of surface annulate-punctate-setose, including large, seta-bearing hemi-punctures. Anterior lobe of metasternum slightly convex, abundantly punctate-setose, disc micropunctate; metasternal sides and adjacent parts matt, abundantly to densely annulate-punctate-setose. Abdominal ventrites matt, each laterally with row of seta-bearing annulate punctures. Pygidium black, matt (microreticulate), with abundant, shallow, fine punctation, without macro-setae; surface slightly convex, base with transverse ridge, apex marginate.

Legs robust. Protibia with 3+1 larger external denticles (distal 3 longer, sub-acuminate), separated by some fine serration; proximal serration consisting of 8 smaller denticles; apico-external denticle oblique to tibial axis; apical edge slightly round, with strong, down-curved, elongate-acuminate spur; protibial underside with low longitudinal crest; protarsus unmodified. Profemur robust, underside finely punctate and with numerous larger seta-bearing hemi-punctures. Meso- and metafemoral undersides also finely punctate, with fewer large seta-bearing hemi-punctures. Meso- and metatibiae strongly dilated distad to transversely subelliptic crest, which is fringed with fine fossorial spines; external side with ca 4 sets of distinct, spine-bearing fossorial protrusions. Tarsi generally slender, with well-developed sickle-shaped claws; meso- and metatarsomeres 1 long, straight, unmodified. Spurs on meso- and metatibiae elongate-acuminate. Relative length proportions of metatibial spur to metatarsomeres 1-5: ca 28, 33, 13, 9, 7, 14.

Parameres narrow (dorsal view), tapering, curved downward (lateral view), Fig. 17.

Measurements (in dorsal view): maximum width of head 3.4 mm, median length of pronotum 3.5 mm, maximum width of pronotum 6.0 mm, sutural length of elytra 5.5 mm, maximum width of combined elytra 6.3 mm.

Variability and sexual dimorphism.

Only male holotype is known.

Etymology.

The name of the new species is derived from the nameof the type locality, a village in the central mountain chain, on the Indonesian side of the Indonesian-Papuan New Guinea border; to be treated as masculine noun.