Pulcherhybosorus tridentatus Yan, Bai

Yan, Zhuo, Bai, Ming & Ren, Dong, 2012, A new fossil Hybosoridae (Coleoptera: Scarabaeoidea) from the Yixian Formation of China, Zootaxa 3478, pp. 201-204 : 203-204

Pulcherhybosorus tridentatus Yan, Bai , & Ren, new species

( Figs. 1–4 )

Holotype. S ex unknown, registration number CNU-COL-NN2011002P/C, part and counterpart. Deposited in the Key Lab of Insect Evolution & Environmental Changes, College of Life Sciences, Capital Normal University, Beijing, China.

Description. Body large, nearly oval; body length: 11.9 mm, width: 5.3 mm. Head. Narrower than pronotum, head length: 2.1 mm, width: 2.2 mm; eyes large; anterior margin of clypeus moderately emarginate; labrum and mandibles prominent, produced beyond apex of clypeus ( Fig. 5 ). Antennae with a 3-antennomere lamellate club, club compact ( Fig. 8 ). Pronotum. Length: 2.0 mm, width: 3.4 mm; wider than elytra and head; widest at base, width 1.7 times the length. Shape nearly trapezoidal, anterior margin of pronotum concave with lateral margins slightly convex, posterior margin slightly protruding. Scutellum, not preserved. Elytra and hind wing. Elytra: long and narrow, about 2.3 times as long as wide; elytra length: 6.0 mm, width: 2.6 mm; widest at middle, slightly constricted at base; convex, constricted at the apical quarter. Striae well defined, elytra without tubercles, lateral margins curved, humeral umbone well developed. Hind wing: the hind wings preserved, well developed; the RP, RA3+4, MP1+2, MP3, RP 3+4, RP 2 and RA4+ RP 1 veins are visible on the fossil ( Figs. 1, 2 , 3 , 7 ). Abdomen. Length: 3.7 mm with five visible sternites; abdominal segment 1 with length 0.4 mm, segments 2 and 3 both with length 0.5 mm, segment 4 with length 0.6 mm, segment 5 with length 1.7 mm. Pygidium, slightly convex; length 0.7 mm, width at base 2.3 mm. Legs. Procoxa about 2.3 times wider than long; protibia dilated apically and with three teeth on outer margin; protarsus preserved with only two tarsomeres in this specimen. Mesofemur and metafemur slender; mesotibia and metatibia slightly dilated at apex, mesotibia with 2 subequal spurs ( Fig. 6 ). Transverse carina on the mesotibia and metatibia absent; mesotarsus with two symmetrical claws and 5 tarsomeres; metatarsus preserved with only 3 segments in this specimen. Measurements. Body length 11.9 mm, body width 5.3 mm, head length 2.1 mm, head width 2.2 mm, pronotum length 2.0 mm, pronotum width 3.4 mm, elytra length 6.0 mm, elytra width 2.6 mm.

Etymology. The specific name is derived from Latin for three teeth, referring to dentation of the protibia.

Figures

FIGURES 1 – 2. Pulcherhybosorus tridentatus photographs of the holotype. 1 — CNU-COL-NN 2011002 P (dorsal view of body), 2 — CNU-COL-NN 2011002 C (ventral view of body).

FIGURES 3 – 4. Pulcherhybosorus tridentatus line drawings of the holotype. 3 — dorsal view of body; 4 — ventral view of body.

FIGURES 5 – 8. Pulcherhybosorus tridentatus magnified photographs of some details, 5 — labrum and mandibles; 6 — two spurs on the end of mesotibia; 7 — hind wing; 8 — antennae.