Amberathyreus beuteli Bai et Zhang, 2017

Bai, Ming, Nie, Ruie, Zhang, Weiwei, Ren, Dong, Shih, Chungkun & Yang, Xingke, 2017, The first fossil Athyreini beetle (Coleoptera: Geotrupidae), Organisms Diversity & Evolution (New York, N. Y.) 17 (1), pp. 157-162 : 158-159

Type species Amberathyreus beuteli Bai et Zhang sp. nov.

Etymology It is directly from amber, itself a derivative of ambra (L.), and near genus Athyreus in morphology. Gender masculine.

Diagnosis This genus could be classified into Athyreini by a combination of the following characters: posterior edge of pronotum moderately to strongly produced forming mesal lobe; preapical surfaces of metatibia with transverse or oblique ridges or combs; scutellum very elongate, twice as long as wide or longer; head and pronotum as long as elytra; middle coxae very widely separated; pygidium concealed; antenna 11-segmented, antennal club three-segmented. The key to the extinct and extant genera of Athyreini , including Amberathyreus Bai et Zhang gen. nov., is given above.

† Amberathyreus beuteli Bai et Zhang sp. nov. ( Figs. 1 , 2 , and 3)

Holotype: sex unknown but likely a female (see discussion for details), a nearly complete specimen (No. BU-002290); the piece of amber containing the specimen was ground and polished to a 17.1 × 11.4 × 10.1-mm cube (1.14 g in weight). The type specimen, currently housed in the Institute of Zoology , Chinese Academy of Sciences ( IZAS), will be eventually deposited in the Three Gorges Entomological Museum, Chongqing, China (specimen available for study by contacting MB or WWZ).

Etymology This species is named in honor of Dr. R. G. Beutel, in recognition of his extraordinary contribution to the research of beetles.

Description Body length: 11.1 mm; width: 4.5 mm. Oval and compact.

Head: Slightly longer than wide, ovate, broadest at eyes; labrum partly visible with long setae; clypeus anterior margin near straight, with a longitudinal carina in the middle connect- ed anterior and posterior margins; frons with two tubercles near anterior margin; eyes slightly protuberant, anterior or mesal edge of eye emarginated; antennae 11-segmented, with three-segmented lamellate club, club near two times as long as the total length of antennomeres 2–8, antennomeres 2–8 gradually broadened toward apex, antennal club layered lamellate; mandible prominent and produced beyond apex of labrum, significantly wider than clypeus; maxillary palp foursegmented; right mandible with one distinct lateral lobe. Pronotum: Shape parabolic, 1.1 times wider than long, significantly wider than head, widest in the middle, sides of prothorax round; anterior margin of pronotum straight in the middle, posterior margin of pronotum moderately to strongly produced forming mesal lobe. Scutellum: Well developed, triangular, very elongate, 2.0 times longer than wide. Elytron: Shape parabolic, base of elytra not margined; elytron 2.2 times as long as wide medially, with seven suture-like striae and straiae near base and apex not clear. Legs: Procoxa not visible through a fovea in the lateral pronotal margin, procoxal cavity lacking a spine on the outer posterior margin; protibia dilated apically, with 6 teeth on outer margin, with a long carinas on dorsal and ventral surface, carina with long and erected spines; mesocoxal cavities, ellipse, at middle widely separated, not or slightly oblique; meso- and metatibia slender, preapical surfaces of meso- and metatibia with transverse ridges and with long and erected spines; two spurs on the apex of meso- and metatibia, differing distinctly in length. Abdomen: six-segmented, pygidium concealed.

Figures

Fig. 1 †Amberathyreus beuteli Bai et Zhang gen. et sp. nov., Holotype (No. BU-002290). a Habitus photograph, in dorsal view; b meso- and metatibia; c antennae; d head in dorsal view, two blue arrows indicate two tubercles near anterior margin of frons, two red arrows indicate the start and end of the longitudinal carina in the middle of clypeus; e complete view of the amber cube with a ruler shown the scale. an antennae, cl clypeus, fr frons, la labrum, md mandible, me mesotibia, mt metatibia, mx maxillary. Scale bar 1 mm

Fig. 2 †Amberathyreus beuteli Bai et Zhang gen. et sp. nov., Holotype (No. BU-002290). a Habitus photograph, in lateral view; b protibia in lateral view, with long and erected spines on dorsal and ventral surface; c protibia in ventral view; d scutellum. Scale bar 1 mm