Onthophagus begoniophilus Krikken & Huijbregts, new species

Onthophagus begoniophilus Krikken & Huijbregts, new species

(Figs. 9, 23–24, 72–81)

Material examined. Holotype male (RMNH) from Indonesia: N Sulawesi: Mt Ambang NR, 20 km E of Kotamobagu, alt. 1120 m, 09-13.iv.1985, J. Huijbregts HH443A; multistratal evergreen forest, human excrement traps.

The 2 paratypes are summarized below:

NORTH SULAWESI: MOUNT AMBANG NATURE RESERVE

- Kotamobagu (20 km E of), 1120 m, 9–13.ix.1985, J. Huijbregts, hh443a, multistratal evergreen forest, 2 human excrement traps, 2 in RMNH

- Kotamobagu, (20 km E of), 1200 m, 5–8.xi.1985, J. Krikken, pw12b, multistratal evergreen forest, 2 fish traps, 1 in RMNH

Diagnostic remarks. For tentative group diagnosis, see Krikken & Huijbregts (2011a). This new species is characterized by the combination of the three long projections on its clypeus (in major males) and the matt, asperate elytral microsculpture with associated more-or-less claviform stubbles. In this size class (body length roughly 4–5 mm) some other Oriental-Papuasian Onthophagus with a T-shaped projection or an elongate anteromedian clypeal plate have recently been placed in an operational group with Onthophagus deflexicollis Lansberge, 1883 (Krikken & Huijbregts 2011a, see also group 14 in Boucomont 1914). Onthophagus alfuricus Huijbregts & Krikken, 2012, which has conspicuous anterolateral clypeal lobes similar to those in O. begoniophilus, was tentatively added to this operational group, and occurs in the nearby Moluccas—this species, contrary to our present novelty, is smooth and shiny. A more distant “giant” Oriental congener (up to approximately 13 mm long) with similarly expanded clypeal lobes is Onthophagus (Parascatonomus) egregius Arrow, 1910, ranging from Java and Borneo to Indochina, but this species is certainly not closely related to any of the various smaller forms mentioned here.

Description. Holotype, male. Body length approximately 4.8 mm. Black-brown, largely matt, due to microreticulation (x80) and other microsculpture. Pilosity abundant, mainly pale yellow, nearly all body bristles characteristically claviform, short.

Clypeal apex produced into long, slender, nearly T-shaped, reflexed horn; clypeus on either side produced into apically angulate, anteriorly directed, reflexed lobe; genal border obtusely angular halfway; clypeogenal transition (in this major male) virtually continuous; frontovertex without any protrusions; clypeal surface anteromedially impunctate, shiny; remainder of head densely to crowdedly (sub)ocellate-punctate, matt. Eyes with approximately 6 facet rows across widest point; ratio interocular distance / single maximum eye width approximately 9.

Pronotum moderately, evenly convex, discal midline not impressed; anterior section of lateral border slightly, widely round; anterolateral margin slightly reflexed, angle rounded off, approximately 90°, posterior section slightly sinuate; pronotal base medially virtually immarginate; pronotal derm with crowded large, elongate-elliptic, superficial, (sub)ocellate, punctures (many bristle-bearing); punctures mostly separated by 0.5 their diameter or less.

Elytra brown, lighter (rufous) on basal parts; striae discally well defined, with distinct punctures, mainly separated by 2–4 times their diameter, crenulate on interstriae; interstriae 1–6 slightly generally slightly convex on disc, distinctly raised on steeper distal and lateral declivities (particularly on humeral area); punctures of lateral striae deeply impressed; all interstriae with irregular rows of bristle-bearing microgranules (laterally strongly asperate); interstrial derm irregularly microreticulate (x80); slight intrahumeral impression noticeable.

Antennal club yellow. Metaventrite with vague discal midline impression; most of derm with relatively large, bristle-bearing, ocellate punctation. Abdominal ventrites brown, each with transverse row of bristle-bearing, ocellate punctures. Pygidium slightly convex, matt, brown; virtually crowded with large, superficial, bristlebearing, (sub)ocellate punctures; base with transverse ridge.

Legs brown. Protibia with 3+(1) larger denticles, spur elongate-acuminate (apex worn in holotype). Mesotibiae and metatibiae slender, spurs unmodified. Femoral undersides with numerous bristle-bearing punctures. Metarsomere 1 robust, almost as long as metatarsomeres 2–4 combined; approximate proportions of spur and tarsomeres 1–5: 10// 15/7/4 /3/5.

Aedeagus, Fig. 80 (paratype).

Measurements in mm. Maximum width of head 1.4. Median length of pronotum 1.3, maximum width 2.3. Sutural length of elytra 1.9, maximum width 2.5.

Variation and sexual dimorphism. Body length roughly 4–5 mm. Shape of male head very polymorphic. A minor male (length 3.9 mm) has the clypeal projections poorly developed (less elongate), the apicomedian projection being simply elongate-lobate (tip simply truncate, not T-shaped); the male paratype illustrated here is intermediate. Their clypeogenal edge is at most shallowly interrupted at the suture.

Female has clypeal border anteromedially simply shortly bidentate-sinuate; marginal surface of clypeus more rugulate-punctate.

Etymology. Named after the begonia flowers on the floor of the upland forest in which this species was found.