Byrrhidiini Davis, Deschodt & Scholtz, 2019

Davis, Adrian L. V., Deschodt, Christian M. & Scholtz, Clarke H., 2019, Defining new dung beetle tribes to resolve discrepancies between phylogeny and tribal classification in the subfamily Scarabaeinae (Coleoptera: Scarabaeidae), Zootaxa 4608 (1), pp. 131-144 : 134-136

Tribe Byrrhidiini Davis, Deschodt & Scholtz , new tribe

Type genus. Byrrhidium Harold, 1869 , here designated ( Figs. 1 , 4 ).

Head. Punctate; anterior clypeal margin often with forklike small to large teeth protruding anteriorly; single very small median tooth on lower margin of clypeus; never with a horn on the frons or vertex; antenna nine segmented; mouthparts varying between genera but labrum always strongly sclerotized apically, inside margins of glossae with sclerotized denticles.

Pronotum. Pronotum convex, with sub-parallel sides; punctation indistinct.

Elytra. Convex; fused without humeral umbones; elytra with seven to eight feebly visible striae followed by an acute sub-lateral pseudoepipleural carina and inflexed pseudepipleuron; interstriae intervals flat; metathoracic wings absent; scutellum not visible from above.

Sterna. Smooth to punctate; sutures well defined.

Protibia. With a terminal spur; two or three denticles on anterior outside margin; posterior outside margin serrated or smooth; tarsi short.

Meso- and metatibia. Unmodified, long and thin; each meso-and metatarsus of uniform width, often setate.

Pygidium. Somewhat convex; punctate.

Aedeagus. Phallobase unmodified; parameres symmetrical and extremely variable.

Body size. Small to medium with size varying between 4.9 mm × 3.8 mm for the smallest and 11.8 mm × 7.5 mm for the largest known species.

Diagnosis and known distribution. The Byrrhidiini new tribe, can be distinguished from all other dung beetle tribes by the combination of the following characters: flightless with body medium sized, sparsely setate and strongly convex; antennae nine segmented; labrum sclerotized apically, inside margins of glossae with sclerotized denticles; punctures on pronotum visible but indistinct; an acute sub-lateral pseudoepipleural carina and inflexed pseudepipleuron; striae and punctures on the elytra indistinctly visible; no humeral umbone visible; scutellum not visible from above; unmodified meso- and metatibiae of the same width; distributed in the arid to hyper-arid region along the southwest seaboard of Namibia and South Africa between about 21 and 31 degrees south with most known species occurring in Namibia ( Fig. 4 ).

Figures

FIGURE 1. Byrrhidium ovale Harold, 1869, type species of the type genus of the tribe Byrrhidiini Davis, Deschodt & Scholtz, new tribe.

FIGURE 4. Map showing the distribution of known species in the tribe, Byrrhidiini Davis, Deschodt & Scholtz, new tribe. Map adapted from Deschodt & Davis (2018).