Onthophagus seseba Krikken & Huijbregts

Krikken, J. & Huijbregts, J., 2017, Sulawesi Onthophagus: seven new species in select groups (Coleoptera: Scarabaeidae: Scarabaeinae), Zootaxa 4238 (3), pp. 301-334 : 329-330

Onthophagus seseba Krikken & Huijbregts , new species

( Figs. 12 , 30 , 68–73 )

Material examined. Holotype male ( RMNH) from Indonesia: Central Sulawesi: Banggai District: Batui: Seseba Estate , 80 m, 6–9.xi.1989, J. Krikken & K. van der Blom sw30a; multistratal evergreen forest, human excrement traps.

The 15 paratypes are summarized below:

CENTRAL SULAWESI: BANGGAI DISTRICT

- Batui: Seseba Estate, 80 m, 6–9.xi.1989, Krikken & Van der Blom, sw30a, multistratal evergreen forest, 4 human excrement traps, 16 in RMNH

Description. Holotype, male. Body length approximately 3.8 mm. Largely black, with orange elytral markings, dorsal side matt. Pilosity abundant, pale yellow, dorsal side with inconspicuous short (white) setae.

Clypeal border round-truncate, clypeogenal transition continuous; clypeofrontal transition with fine arcuate ridge just reaching clypeogenal sutures on either side; head densely punctate throughout, punctures distinct, with pale microstubble. Eyes with approximately 6 facet rows across widest point; ratio interocular distance / single maximum eye width approximately 10.

Pronotum evenly moderately convex, discal midline not impressed; anterior section of lateral border widely round, posterior section slightly sinuate to obtuse posterolateral angle; pronotal base indistinctly, finely marginate. Pronotum with disc densely, superficially but densely annulate-punctate, punctures with short seta (length mainly twice punctural diameter); punctures on lateral declivities smaller, deeper, more irregular.

Elytra bicoloured; striae well defined, shallow, with distinct punctures; mostly separated by 2–4 times their diameter, distinctly crenulate on interstriae; discal interstriae flat, with irregular rows of seta-bearing microgranulae (setae fine, short), derm generally microreticulate; surface of lateral interstriae more uneven, almost rugulatepunctate, more shiny.

Antennal club yellowish brown. Metaventrite shiny brown, without distinct midline impression, anterior lobe with slight median ridge in front; most of discal surface with abundant fine punctation; lateral wings with coarser, more-or-less annulate punctation, with longer setae. Abdominal ventrites with transverse row of (more-or-less annulate) punctures, setae appressed caudad. Pygidium evenly convex, abundantly punctate-setose; base with transverse ridge.

Protibia with 3+(1) larger external denticles; spur curved-acuminate. Metatibial spur long, tapering. Femoral undersides all with (more-or-less scattered) seta-bearing punctures. Metatarsomere 1 shorter than 2–5 combined; approximate proportions of spur and metatarsomeres 1–5: 11// 13/6/4 /3/5.

Aedeagus, Fig. 72 (holotype).

Measurements in mm. Maximum width of head 1.1. Median length of pronotum 1.2, maximum width 1.9. Sutural length of elytra 1.6, maximum width 2.1.

Variation and sexual dimorphism. Body length 3–4.5 mm. Microsculpture, pilosity, and colour slightly variable.

Females with distinct, low clypeofrontal ridge, sexual dimorphism otherwise insignificant.

Etymology. Named for the type locality in eastern Central Sulawesi. This name should be treated as a noun in apposition.

Figures

FIGURES 9 – 12. Sulawesi Onthophagus species, oblique habitus. 9, O. begoniophilus, paratype male from Ambang. 10, O. annulopunctatus, paratype male from Mogogonipa. 11, O. hollowayi, holotype male from Dumoga. 12, O. seseba, holotype male from Batui (pygidium up). Scale lines approximately 1 mm.

FIGURES 25 – 30. Sulawesi Onthophagus species, dorsal forebody. 25, O. sopu, holotype male from Sopu. 26, O. sopu, paratype male from Sopu. 27, O. manguliensis, male from Mangoli. 28, O. annulopunctatus, paratype male from Mogogonipa. 29, O. hollowayi, holotype male from Dumoga. 30, O. seseba, holotype male from Batui. Scale lines approximately 1 mm.

FIGURES 68 – 81. Sulawesi Onthophagus body parts. 68, O. seseba, head full-face, holotype male from Batui. 69, O. seseba, left elytron dorsal, holotype male from Batui. 70, O. seseba, protibial upper side, holotype male from Batui. 71, O. seseba, metatibial upperside, holotype male from Batui. 72, O. seseba, aedeagus lateral, holotype male from Batui. 73, O. seseba, head full-face, paratype female. 72, O. begoniophilus, aedeagus lateral, holotype from Ambang. 73, O. begoniophilus, head fullface, holotype from Ambang. 74, O. begoniophilus, head full-face, holotype from Ambang. 75, O. begoniophilus, left elytron dorsal, holotype from Ambang. 76, O. begoniophilus, head full-face, paratype male. 77, O. begoniophilus, left elytron caudal, paratype male. 78, O. begoniophilus, protibial upper side, paratype male. 79, O. begoniophilus, metatibial upperside, paratype male. 80, O. begoniophilus, aedeagus lateral, paratype male. 81, O. begoniophilus, head full-face, paratype female. Scale lines approximately 1 mm.