Rhytomus latidentatus Saxton & Génier, 2025

Génier, François, Gunter, Nicole L. & Saxton, Natalie A., 2025, Rhytomus Génier & Saxton: A new dung beetle genus from New Guinea with five new species and phylogenetic insights (Coleoptera: Scarabaeidae: Scarabaeinae), Zootaxa 5575 (1), pp. 87-110 : 102-103

Rhytomus latidentatus Saxton & Génier , new species

urn:lsid:zoobank.org:act:8C418C61-9081-48AD-B9BB-6CBC74D23206

Figs. 4C, 4E , 7E , 8E , 10A , 12A

Name-bearing type data. Holotype ♂ ( CMNC). || PAPUA NEW GUINEA: Western | Prov., P’nvang , CI RAP Survey | Camp 1. 05º29.5S 141º32.6E | 573 m. May 2013. T. Larsen ||; || Canadian Museum of | Musée canadien de la | NATURE | CMNEN 00049540 || [QR code label]; || HOLOTYPE ♂ | Rhytomus | latidentatus | Des. N. Saxton & F. Génier, 2024 || [red card] .

Material examined (22 ♂♂, 12 ♀♀). PAPUA NEW GUINEA: CENTRAL PROVINCE, Kokoda Trak, Kauai River , Menari , 700 m, [09°11’30’’S, 147°37’30’’E], 12–14.viii.1976, rainforest, dung, O. Kukal — 3 ♂♂, 1 ♀ paratypes ( CMNC), 2 ♂♂ paratypes ( MNHN); WESTERN PROVINCE, CI RAP Survey Camp 1 , P’nvang , 575 m, 05°29’S, 141°32’E, v.2013, T. Larsen — 1 ♂, 1 ♀ paratypes ( ANIC), ♂ holotype, ♀ allotype , 14 ♂♂, 8 ♀♀ paratypes ( CMNC), 1 ♂, 1 ♀ paratypes ( QM) .

Description. Measurements. Body length 4.5–6.3 mm, maximum body width 3.1–4.2 mm. Holotype: length 5.5 mm, maximum body width 3.9 mm. Body. Overall body shape in dorsal view oval, elytral edge evenly rounded from base to apex. Head. Clypeal edge lateral to clypeal teeth lacking emargination, clypeal teeth wide, head margin at clypeogenal suture of females slightly protruding. Dorsal parts of eyes semi-ovoid, separated by an interocular space of about 5.1 times eye width. Pronotum. Pronotal width to length along midline ratio 1.6, lateral pronotal edge sharply defined throughout, pronotal pubescence short and fine, pronotal basal portion along midline with fine longitudinal depression. Elytra. Elytral maximum width to length along suture ratio 1.0, elytral outline moderately convex in lateral view, elytral pubescence long and conspicuous, elytral surface between punctures with distinct microsculptures ( Fig. 12A ), basal elytral pit absent, basal surface of pseudepipleuron with irregularly distributed more or less defined punctures, interstriae 3–5 on basal fifth with two rows of punctures along striae with the odd unaligned punctures on interstriae 3 and 5 and scattered unaligned punctures on interstria 4. Legs. Profemoral anterior surface flat, male metatibial apicointernal teeth approximately in line with posterior tibial edge. Pygidium. Pygidial groove transverse, narrowed medially, and terminating in a pit at each end ( Fig. 8E ), surface along midline with punctures similar in density to rest of discs, pygidial surface along basal groove smooth between punctures, pygidium of female evenly convex. Aedeagus. Left paramere apex rounded in a dorsoventral plane ( Fig. 10A ). Female genitalia. Spermatheca with two apodemes basally and one apodeme apically.

Etymology. The specific epithet of this species is a combination of the Latin adjective “ latus ” meaning wide and the adjective “ dentatus ” meaning dentate in reference to this species’ characteristically wide clypeal teeth.

Remarks. Paulian (1985) studied four specimens of this species which he identified as “ Tesserodon heurni ” in his work on the Canthonines of New Guinea.

Figures

FIGURE 4. Diagnostic characters of Rhytomus. A, dorsal head showing emargination and interocular space (R. howdeni); B, dorsal head showing lack of emargination and interocular space (R. fervidus) C, ventral view of male foreleg (R. latidentatus); D, lateral view of elytra (R. vanus); E, dorsal view of male protibia (R. latidentatus).

FIGURE 7. Habitus of Rhytomus species in mainland New Guinea. A, R. fervidus; B, R. heurni; C, R. howdeni; D, R. larseni; E, R. latidentatus; F, R. papuanus; G, R. setulosum; H, R. sodalis; I, R. vanus; Scale bar = 1 mm.

FIGURE 8. Pygidium of Rhytomus species. A, male R. fervidus; B. female R. heurni; C, male R. howdeni; D, male R. larseni; E, male R. latidentatus; F, male R. papuanus; G, female R. setulosus; H, male R. sodalis; I, male R. vanus. Scale bar = 0.2 mm.

FIGURE 10. Male aedeagus of Rhytomus species, left lateral, dorsal, right lateral. A, R. latidentatus; B, R. papuanus; C, R. sodalis; D, R. vanus. Scale bar = 0.5 mm.

FIGURE 12. Characters used for species identification. A, elytral surface with microsculpture (R. latidentatus); B, elytral surface glossy (R. fervidus); C, male metatibial apicointernal tooth in line with posterior tibial edge (R. sodalis); D, male metatibial apicointernal tooth set anteriorly to posterior tibial edge (R. larseni); E, lateral view of strongly convex elytra (R. setulosus); F, lateral view of moderately convex elytra (R. vanus).