Miridiba (Miridiba) bannaensis Gao & Fang, 2018

Gao, Chuan-Bu, Bai, Ming, Fang, Hong & Yu, Zhi-Guo, 2018, Four new species of the genus Miridiba Reitter (Coleoptera: Scarabaeidae: Melolonthinae) from China, Zootaxa 4527 (1), pp. 1-20 : 2-4

Miridiba (Miridiba) bannaensis Gao & Fang , new species

( Figs. 1 , 6 )

Type locality. CHINA: Yunnan Province: Xishuangbanna City .

Type material examined. Holotype, male, labelled: “ Xiaomengyang, Yunnan 850 m / 1957. V. 3 / Qiuzhen Liang [typeset, Chinese and Russian ] // Holotrichia (P.) imitatrix Brsk. ♂ / identified by Youwei Zhang 1961. VI [handwritten] // IOZ(E) 1967839 [typeset] // HOLOTYPE ♂ / Miridiba bannaensis sp. nov. / Chuanbu Gao and Hong Fang / det. 2018 [typeset, red label]”, deposited in IZCAS; paratype, female: “Xiaomengyang, Yunnan 850 m / 1957. V. 3 / Qiuzhen Liang [typeset, Chinese and Russian] // Holotrichia (P.) imitatrix Brsk. ♀ / identified by Youwei Zhang 1961. VI [handwritten] // IOZ(E) 2016205 [typeset] // PARATYPE ♀ / Miridiba bannaensis sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratype, male: “ Yunnan Xishuangbanna Mengla / 1982-?-22/19 / Wang Sumei Zhou Jingruo [handwritten, Chinese] // PARATYPE ♂ / Miridiba bannaensis sp. nov. / Chuanbu Gao and Hong Fang / det. 2018 [typeset, yellow label]”, deposited in NWAFU; paratype, male: “Nannuoshan, Menghai, Yunnan 1200 m / 1957. IV. 29 / Lingchao Zang [typeset, Chinese and Russian] // H. imitatrix / genitalia / 62.2.17 [handwritten] // PARATYPE ♂ / Miridiba bannaensis sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS.

Description of holotype (male). Body length 20.3 mm; width across humeri 8.5 mm, strongly convex, body oval-elongate, dorsal surface glabrous.

Colour: Head, pronotum, scutellum and legs dark reddish brown; antennae, elytra and abdomen dark brown to dark reddish brown; shiny ( Figs. 1a, b ).

Head: Frons densely punctate; clypeus with apex distinctly bilobed and reflexed; fronto-clypeal suture waveshaped; frontal carina distinctly raised, weakly curved backwards at middle; clypeus shorter than frons, length ratio between clypeus and frons before carina 0.58; distance between eyes four times wider than eye ( Fig. 1c ). Antenna with 9 antennomeres; antennal club composed of 3 antennomeres, longer than antennomeres 2–6 combined ( Fig. 1d ).

Thorax: Pronotal surface densely punctate and glabrous; pronotum widest near posterior half; anterior margin smooth and flanged; anterior margin with an arc-shaped incision at each end; lateral margin smooth and reflexed at anterior half; posterior margin smooth; anterolateral angles 90°, posterior angles obtuse and round ( Fig. 1e ). Prosternal process basiconic shaped, top flat. Scutellum triangular, dorsal surface glabrous and densely punctate, 1.43 times wider than long. Dorsal surface of elytra glabrous, sutural costae developed, epipleuron with cilia ( Figs. 1a, b ).

Legs: Protibia tridentate, denticle 2 sharp; dorsal carina forking to denticle 2; apical spur reaching basal 2/5 of protarsomere 1. Metafemora moderately covered with long soft hairs near anterior and posterior margins; outer side of metatibia with 1 completed carina at distal 2/5, arc-shaped. Dorsolateral margin of metatibia has two thorns; dorsomedial margin with four thorns small to large ( Fig. 1f ); metatibia with two apical spurs of different sizes; metatarsomere 1 equal in length to metatarsomere 2; each metaclaw with a vertical tooth at middle ( Fig. 1g ).

Abdomen: Lateral sides of abdominal sternites densely punctate and setiferous, setae short; posterior sternites 5 and 6 covered with long soft hairs.

Pygidium: Fan-shaped pygidium punctate and setiferous, 1.38 times wider than long; dorsal surface covered with tiny setae, apical pygidium with long soft hairs; apical pygidium at a right angle.

Male genitalia. Phallobase: Phallobase 1.07 times longer than paramere; dorsal surface with a depressed sulcus at middle; anterior 1/5 of phallobase constricted. Parameres: Parameres with four branches: two dorsal branches 1.35 times longer than two ventral branches. Dorsal branches extended forwards and curved inwards subapically, then divergent at apex; ventral sides of dorsal branches with several setae; basal third of paramere with two quadrangular plates on dorsum; ventral branch with a big cone-shaped hook ventrally before the apex ( Figs. 1h, i ). Endophallus with temones tapered in dorsum and epithelium in distal end; epithelium covered within soft sensillae densely and short spurs ( Fig. 1j ).

Female. Antenna with 9 antennomeres; club formed with 3 antennomeres, slightly shorter than antennomeres 2–6 combined. Anterior metatibia slightly wider than in male.

Variability. Both paratypes slightly differ in size (total body length 19.4–20.4 mm, width across humeri 8.4– 9.1 mm).

Diagnosis. Miridiba bannaensis new species can be separated from other Miridiba species by the following combination of characters: the punctures of pronotum and scutellum deep and rugose; the anterior margin has an incision at each end, the anterolateral angles prolonged forwards and moderately reflexed; in the paramere, distal end of ventral branches with a big cone-shaped hook along ventral margin near apex.

Distribution. China (Yunnan: Puer, Xishuangbanna) ( Fig. 6 ).

Etymology. The name of the new species is from the type locality, Xishuangbanna.

Chinese name. 版纳脊鳃金龟

Remarks. All specimens mentioned above of M. (M.) bannaensis new species were incorrectly identified as Holotrichia (Pledina) imitatrix Brenske, 1899 by Chang (1964). The two species can be separated by the following combination of characters: the shape of punctures on the scutellum (big and rugose in M. (M.) bannaensis new species; small in M. (M.) imitatrix ;), the longitudinal carina in the middle of the clypeus (absent in M. (M.) bannaensis new species; present in M. (M.) imitatrix ) and the form of the parameres (tips of dorsal and ventral branches bent downwards in M. (M.) bannaensis new species; dorsal branches slender and sharp, tips of ventral branches bent in M. (M.) imitatrix ).

Figures

FIGURE 1. Miridiba (M.) bannaensis Gao & Fang, new species, holotype. a, habitus, dorsal view; b, habitus, lateral view; c, head, dorsal view; d, antenna; e, pronotum, dorsal view; f, metatibia, lateral view; g, metaclaws; h, parameres, lateral view; i, paramere, dorsal view; j, endophallus, ventral view. Scale bar: 5 mm for a, b; 1 mm for c, e, f, h, i, j; 0.5 mm for d, g.

FIGURE 6. Distribution map for six Miridiba species in China.