Onthophagus kukali Krikken & Huijbregts

Krikken, J. & Huijbregts, J., 2013, New Guinea Onthophagus: taxonomy of ten small, unicolored new species (Coleoptera: Scarabaeidae: Scarabaeinae), Zootaxa 3619 (5), pp. 501-525 : 513-514

Onthophagus kukali Krikken & Huijbregts , new species

( Figs. 9, 20 , 69–73 )

Type material. Holotype male (CMNC) from PNG: 8 km SW Nadro, 650 m, Ofi Creek, 15–18.viii.1976, O. Kukal, dung, lowland rainforest. Paratypes listed in Appendix 1.

Diagnosis. This small species (body length usually 3.0– 3.5 mm) may stand closer to some of the preceding broad-eyed species than to O. kokodentatus -like forms, judged from its general shape and characteristic ocellate punctation. It looks like a narrow-eyed mini-version of O. kokocellosus , described above, and is hypothesized to be related in such a way that the group position must be reconsidered. The head of O. kukali is without even the slightest protrusion. Punctation of pronotum and elytra with distinct bristles. Pygidium ocellate-punctate.

Description (holotype, male). Body length approximately 3 mm. Habitus convex, dorsum slightly deplanate. Color largely dark-brown (almost black), dorsum hardly shiny, due to crowded punctation; legs brown. Pronotal, elytral, and pygidial punctation with short, erect whitish bristles (shorter than punctural diameter); underside with numerous short pale-brown bristles and longer setae; most of punctation ocellate, sharply defined, generally isodiametic.

Head brown (margin light-brown), almost entirely finely, distinctly, densely punctate, larger punctures interspersed with fine ones. Clypeal border widely, evenly rounded from vague clypeogenal transition to broadly bisinuate anterior border, margin not reflexed; clypeogenal transition virtually continuous at border; clypeogenal suture virtually effaced; clypeofrontal surface evenly, slightly convex, without any protrusions. Genal border almost straight in front, lateral tip shortly rounded, posterior extension tapering and just reaching occipital side. Eye foramina narrowly subelliptic, with 4–5 facet rows across widest point. Ratio interocular distance / maximum eye width 12–13.

Pronotum dark-brown, (on magnification) shiny between crowded, ocellate punctation, punctures with short bristle; surface moderately, evenly convex (lacking midline impression); anterior declivity gradual, unmodified; anterior and lateral borders finely marginate; base very finely marginate; anterior section of lateral border widely rounded, anterolateral angle fully rounded; posterior section of lateral border extremely slightly concave (full-face view), posterolateral angle hardly distinct, rounded off; pronotal lateral and basal borders widely rounded in dorsal view.

Elytra dark-brown to black, (on magnification) shiny between interstrial punctures; scutellum indistinct, shape of base and apex unmodified; epipleuron glabrous, punctate, brown, matt. Elytra broad, with 8 straight to slightly curved, fine striae; stria 7 evenly, very slightly curved in front, ending at humeral umbone; strial punctures more or less distinct (depending on angle of view), usually separated by 4–7 puncture diameters, slightly affecting interstrial surface. Interstrial surfaces very slightly convex, with crowded, shallow, ocellate punctation, on disc usually 3 punctures over width between adjacent striae.

Antennal club light brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus concave, matt, posteriorly delimited by simple coxal-marginal ridge. Propectoral sides with matt.

Metasternum shiny, anterior lobe slightly prow shaped in front; metasternal lobe and disc with slight midline impression, finely punctate; metasternal flanks shiny, with numerous ocellate punctures. Abdominal ventrites matt, each laterally with more or less distinct rows of ocellate punctures, anal ventrite with more punctures, somewhat shiny. Pygidium matt, shiny between punctures; base with fine transverse ridge, sides very finely marginate; surface slightly, evenly convex, with very crowded, strong, ocellate, bristle-bearing punctures.

Legs short, generally shiny light brown. Protibia robust, with 3+1 larger external denticles (distal 3 long, subacuminate, proximal one short), distinctly separated by serration; proximal serration consisting of 6–7 small denticles; apico-external denticle oblique to tibial axis; apico-internal angle unmodified, terminal spur strong, elongate (tips worn off?); protibial underside with low longitudinal crest; protarsus slender. Profemur robust, underside shiny, with densely punctate, with some longer setae. Mesofemoral and metafemoral undersides with abundant, finer, scattered punctures. Mesotibiae and metatibiae strongly dilated distad to transversely subelliptic crest, which is fringed with short fossorial spines below, and some long, fine spines above; externally with 2 very slight, spine-bearing fossorial protrusions. Mesotarsi and metatarsi generally very slender, slightly complanate, with fine sickle-shaped claws; mesotarsomeres and metatarsomeres 1 long, straight, slightly shorter than 2–5 combined. Terminal spurs on mesotibiae and metatibiae elongate, tapering. Length proportions terminal spur // metatarsomeres 1–5 in approximate integers: 5//6/3/2/1/2.

Parameres with tapering stalks curved downward, Fig. 20 .

Measurements in mm (dorsal view). Maximum width of head 1.10. Median length of pronotum 1.05, maximum width 1.60. Sutural length of elytra 1.50, maximum width combined 1.90.

Variation and sexual dimorphism. Both sexes similar. Body size varies slightly, length 3.0– 3.5 mm.

Comment. If more material of heavily ocellate-punctate close relatives of O. kokocellosus and O. kukali becomes available, again bridging the “eye size divide”, a regrouping of the species must be considered—the present separation is just practical.

Etymology. Named after the collector, O. Kukal.

Figures

FIGURES 13 – 24. Parameres (lateral view) of Onthophagus species. 13, O. acerus, holotype; 14, O. aceroides, holotype; 15, O. baiyericus, holotype; 16, O. daymanus, holotype; 17, O. kokopygus, holotype; 18, O. kokocellosus, holotype; 19, O. bituberoculus, holotype; 20, O. kukali, holotype; 21, O. kokodentatus, holotype; 22 – 23, O. dissidentatus, paratype, Wau (22), paratype. N Port Moresby (23); 24, O. ofianus, holotype. Scale lines (on top of relevant parameres) equal 0.5 mm.

FIGURES 58 – 73. Onthophagus species, body parts. 58 – 62, O. bituberoculus, holotype; 63, O. bituberoculus (or near), male; 64 – 68, O. kokocellosus, holotype; 69 – 73, O. kukali, holotype. — Head (full-face) 58, 63, 64, 69; pronotum (dorsal) 59, 65, 70; left elytron (dorsal) 60, 66, 71; protibia (upper side) 61, 67, 72; metatibia (upper side) 62, (underside) 68, 73. Scale lines equal 1 mm.