Onthophagus daymanus 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 : 509-510

Onthophagus daymanus Krikken & Huijbregts , new species

( Figs. 6 , 16 , 45–49 )

Type material. Holotype male (AMNH) from PNG: Mt Dayman, Maneau Range, N slope, 700 m, Camp 6, 20–26.vii.1953, G.M. Tate, 4th Archbold Expedition. See the report of Brass (1956) for a description of the type region. Paratypes listed in Appendix 1.

Diagnosis. Generally black-brown, more matt compared to O. kokopygus , dorsum being crowded with fine ocellate punctation. Pygidium canaliculate-punctate, as in preceding species. Tip of longer mesotibial spur incised. Clypeal border anteriorly bisinuate. Clypeofrontal transition with transverse elevation. Eye foramina large, open behind, i.e., tapering posterior end of gena just not reaching occipital side; interocular distance approximately 3 eye widths. Genal tip shortly rounded. Frons with slight transverse ridge, between (and not reaching) eyes. Small, body length usually 4.5–5.0 mm.

Description (holotype, male). Body length approximately 4.5 mm. Habitus convex, dorsum slightly deplanate. Color largely black-brown, matt due to crowded punctation on dorsum; venter largely dark brown, legs brown. Pronotal, elytral, and pygidal punctation with short, white bristles (about as long as punctural diameter); underside with numerous short pale-brown bristles and longer setae; most of punctation ocellate, sharply defined, generally isodiametic.

Head black, almost entirely finely, distinctly punctate, punctural diameters largely similar, punctuation abundant on clypeus, crowded on frons and genae. Clypeal border widely, evenly rounded from vague clypeogenal transition to broadly, slightly bisinuate anterior border, margin not reflexed; clypeogenal transition continuous at border; clypeogenal suture virtually effaced; clypeofrontal transition with slight, short, transverse elevation. Genal border very widely rounded in front, lateral tip shortly rounded, posterior extension tapering and just not reaching occipital side. Frontal surface between eyes with very slight transverse ridge, not reaching eyes. Eye foramina broadly subelliptic, with approximately 17 facet rows across widest point. Ratio interocular distance / maximum eye slightly over 3.

Pronotum virtually black, moderately shiny between crowded, fine, distinct, ocellate punctation; 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 distinct, but rounded off; pronotal lateral and basal borders widely rounded in dorsal view.

Elytra dark brown, (on magnification) shiny between interstrial punctures; scutellum indistinct, shape of base and apex unmodified; epipleuron glabrous, brown, matt, vaguely asperate. Elytra broad, with 8 straight to slightly curved, striae; stria 7 evenly, very slightly curved in front, ending at humeral umbone; strial punctures moderately distinct, on disc mostly separated by 4–8 puncture diameters, crenulating interstriae. Interstrial surfaces very slightly convex, with crowded, shallow, fine, ocellate punctation, on disc usually 3–5 punctures over width between adjacent striae.

Antennal club brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus concave, matt, posteriorly delimited by simple coxal-marginal ridge. Propectoral sides with may fine punctures. Metasternum shiny, anterior lobe very 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 with general surface slightly, evenly convex, strongly canaliculate: matt in well-defined, curvy channels, shiny brown on raised “islands”; base with transverse ridge, apex broadly marginate.

Legs slender, generally shiny brown. Protibia robust, with 3 larger external denticles (distal 3 long, subacuminate, proximal one obsolete), distinctly separated by serration; proximal serration consisting of 8–9 small denticles (proximal 4th included); 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, irregularly punctate. Mesofemoral and metafemoral undersides with numerous scattered punctures. Mesotibiae and metatibiae very strongly dilated distad to transversely subelliptic crest, which is fringed with short fossorial spines below, and some long, fine spines above; externally with 3 slight, spine-bearing fossorial protrusions. Mesotarsi and metatarsi generally somewhat compactcomplanate, with very fine sickle-shaped claws; mesotarsomeres and metatarsomeres 1 long, straight, unmodified, shorter than 2–5 combined. Terminal spurs on mesotibiae and metatibiae elongate, tapering (longer one on mesotibiae with rounded-hooked tip). Length proportions terminal spur // metatarsomeres 1–5 in approximate integers: 7//9/4/2/2/3.

Parameres short, with tips tapering (full-face view), bent downward (lateral view), Fig. 16 .

Measurements in mm (dorsal view). Maximum width of head 1.5. Median length of pronotum 1.5, maximum width 2.3. Sutural length of elytra 2.3, maximum width combined 2.6.

Variation and sexual dimorphism. Sexes very similar, transverse elevations on head of females reduced. A female singleton from Mt Hagen has smaller eyes (foramina separated by 4.5 eye widths), and is not listed here (excluded from the type series).

Etymology. Name refers to type locality; to be treated as masculine noun.

Figures

FIGURES 1 – 8. Habitus (oblique view) of Onthophagus species, with indication of body length. 1, O. acerus, holotype ,, 6 mm; 2, O. aceroides, holotype, 5 mm; 3, O. baiyericus, holotype, 5 mm; 4, O. mimikanus, female holotype, 6 mm; 5, O. kokopygus, holotype, 3 mm; 6, O. daymanus, holotype, 4.5 mm; 7, O. kokocellosus, holotype, 4.5 mm; 8, O. bituberoculus, female paratype, Timika, 7 mm.

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 40 – 57. Onthophagus species, body parts. 40 – 44, O. mimikanus, female holotype; 45 – 49, O. dayanus, holotype; 50 – 57, O. kokopygus, holotype (50 – 54), female paratype, E Port Moresby (55). — Head (full-face) 40, 45, 50, 55; pronotum (dorsal) 41, 46, 51; left elytron (dorsal) 42, 47, 52; protibia (upper side) 43, 48, 53; metatibia (underside) 44, 49, 54; elytral tips and pygidium 56; mesotibial apex, tarsus, spurs 57. Scale lines equal 1 mm.