Miridiba (Miridiba) youweii 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 : 9-12

Miridiba (Miridiba) youweii Gao & Fang , new species

( Figs. 4 , 6 )

Type locality. CHINA: Yunnan Province: Jingdong Yi Autonomous County .

Type material examined. Holotype, male, labelled: “Jingdong, Yunnan 1170 m / 1956. V. 24 / Kryzhanovsky [typeset, Chinese and Russian] // Holotrichia (P.) hybrida Moser ♂ / Identified by Youwei Zhang 1961. VII [handwritten, Chinese] // IOZ(E) 1967838 [typeset] // HOLOTYPE ♂ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, red label]”, deposited in IZCAS; paratypes, 2 females: “Jingdong, Yunnan 1170 m / 1956. V. 20 / Benshou Zhou [typeset, Chinese] // Holotrichia (P.) hybrida Moser ♀ / identified by Youwei Zhang 1961. VI [handwritten, Chinese] // IOZ(E) 2016206 [typeset] // PARATYPE ♀ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, 9 males and 3 females: “Jingdong, Yunnan 1170 m / 1956. V. 20 / Benshou Zhou [typeset, Chinese and Russian] // PARATYPE / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratype, male: “Jingdong, Yunnan 1170 m / 1956. V. 16 Kryzhanovsky lamp [typeset, Chinese] // PARATYPE Ƌ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratype, male: “Simao, Yunnan 1300 m / 1957. V. 9 / Fuji Pu [typeset, Chinese] // PARATYPE Ƌ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, 2 males and 2 females: “Simao, Yunnan 1300 m / 1957. V. 9 / Guangji Hong [typeset, Chinese] // PARATYPE / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratype, male: “Jingdong, Yunnan 1200 m / 1957. IV. 25 / A. Monchadsky [typeset, Chinese] // PARATYPE Ƌ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, 14 males and 4 females: “Jingdong, Yunnan 1170 m / 1956. V. 22 / B. Popov [typeset, Chinese] // PARATYPE Ƌ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, 4 males: “Jingdong, Yunnan 1170 m / 1956. V. 22 / Zagulyaev [typeset, Chinese] // PARATYPE Ƌ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, 2 females: “ Mengla County, Yunnan 370 mm / 1956. IV. 12 / Keren Huang etc. lamp [typeset, Chinese ] // PARATYPE ♀ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, 7 females: “ Mengla County , Yunnan 370 mm / 1956. IV. 12–18 / Keren Huang etc. lamp [typeset, Chinese and Russian ] // PARATYPE / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratype, female: “ Dong jiafen, Jingdong , Yunnan 1250 / 1956. V. 23 / Kryzhanovsky [typeset, Chinese ] // PARATYPE ♀ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratype, female: “ Jingdong , Yunnan 1200 m / 1957. V. 29 / A. Monchadsky [typeset, Chinese ] // PARATYPE ♀ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, male and female: “ Jingdong , Yunnan 1170 m / 1956. VI. 3 / Kryzhanovsky lamp [typeset, Chinese ] // PARATYPE / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, 22 males and 12 females: “ Jingdong , Yunnan 1200 m / 1957.?. 26–?. 29 / A. Monchadsky [typeset, Chinese and Russian ] // PARATYPE / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, 13 males and 3 females: “Jingdong, Yunnan 1170 m / 1956. V. 21– 27 Kryzhanovsky lamp [typeset, Chinese and Russian] // PARATYPE / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in IZCAS; paratypes, male and female: “ Yunnan, Xishuangbanna, Jinghong / (545 m) / 1974–5 11–15, 22–25 / Yao Zhou, Feng Yuan / Northwest Agriculture College [handwritten or typeset, Chinese] // PARATYPE / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in NWAFU; paratype, male: “Moganshan Lamp / 7.23 / Yanxia Chen [handwritten, Chinese] // PARATYPE Ƌ / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in NWAFU; paratype, male: “ Guizhou, Xingyi / 1979. X. 6 / Yang [handwritten, Chinese] // PARATYPE / Miridiba youweii sp. nov. / Chuanbu Gao & Hong Fang / det. 2018 [typeset, yellow label]”, deposited in SYAU.

Description of holotype (male). Body length 24.0 mm, width across humeri 10.3 mm, body oval-elongate, dorsal surface glabrous. Colour: Head, pronotum, scutellum and legs dark reddish brown; antennae, elytra and abdomen dark brown ( Figs. 4a, b ).

Head: Dorsal surface densely punctate and glabrous; clypeus arcuate, with apex weakly emarginate; anterior margin strongly reflexed; fronto-clypeal suture bilobed; frontal carina distinctly raised, weakly curved backwards; clypeus shorter than frons, length ratio between clypeus and frons before carina 0.55; distance between eyes nearly four times wider than eye ( Fig. 4c ). Antenna with 9 antennomeres; club with 3 antennomeres, equal in length to antennomeres 2–6 combined ( Fig. 4e ).

Thorax: Pronotum widest at basal 1/3; dorsal surface densely punctate; anterior margin smooth and flanged; anterior margin with an incision at each end; lateral margin smooth and reflexed; posterior margin smooth; anterolateral angles 90°, posterior angles obtuse and round ( Fig. 4d ); prosternal process basiconic shaped, top flat. Scutellum triangular, dorsal surface glabrous and densely punctate, punctures tiny; 1.49 times wider than long. Dorsal surface of elytra glabrous, sutural costae developed, epipleuron with several short cilia ( Figs. 4a, b ).

Legs: Protibia tridentate; dorsal carina forking to denticle 2; apical spur of protibia sharp, apical spur reaching basal 1/3 of protarsomere 1. Metafemora covered with long soft hairs near anterior and posterior margins ( Fig. 4b ); outer side of metatibia with 1 completed carina at distal 2/5, carina arc-shaped ( Fig. 4f ). Dorsolateral margin with 1 thorn; dorsomedial margin with 4 thorns small to large ( Fig. 4f ). Metatibia has two apical spurs of different sizes; the big spur lanceolate shaped, reaching basal 1/5 of metatarsomere 2; metatarsomere 1 shorter than metatarsomere 2.

Abdomen: Lateral sides of abdominal sternites densely punctate and setiferous, setae short ( Fig. 4b ); middle area of sternites 3 and 4 sparsely setiferous; sternites 5 and 6 covered with long soft hairs.

Pygidium: Fan-shaped pygidium setiferous and punctured; 1.49 times wider than long.

Male genitalia. Phallobase: Phallobase 1.39 times longer than parameres; dorsal surface with a depressed longitudinal sulcus at middle; anterior 1/4 of phallobase constricted. Parameres: Parameres with two long dorsal branches and two short ventral branches; dorsal branches tapered forwards and bent downwards at basal 1/3, angle of bend 100°, apex curved inwards; ventral branches thick, tips bent outwards, angle of bend 90° ( Figs. 4g, h ). Endophallus: Temones slender and sclerous, colour black, consist of two sclerotised sclerites joined; top of temones with a cluster of short thorns; medial endophallus with thick thorns on dorsum and lots of thin thorns on ventral side; several sensillae on ventral side ( Fig. 4i ).

Female. Antenna with 9 antennomeres; club with 3 antennomeres, shorter than antennomeres 2–6 combined. Apex of metatibia wider than in male; the apical spurs of metatibia in female are broader and blunter than in male.

Female genitalia ( Fig. 4j ). Female genitalia consists of a genital chamber, accessory glands, oviduct, median oviduct, spermatheca, spermathecal gland, bursa copulatrix. Genital chamber: Two pairs of symmetrical vestigial tergites located at both sides of rectum; terminal genital chamber with a pair of vestigial sternites ventrally, bilaterally symmetrical and setigerous. Accessory glands: horseshoe-shaped glands. Median oviduct: Median oviduct with 2 rounded sclerotised sclerites on lateral sides and 1 sclerotised sclerite on dorsum. Bursa copulatrix: pear-shaped. Spermatheca and spermathecal gland: tube-shaped.

Variability. The known paratypes slightly differ in size (total body length: 22.0–24.0 mm, width across humeri 10.0– 12.2 mm).

Diagnosis. Miridiba (M.) youweii new species is distinguished from Miridiba (M.) thai Keith, 2010 by numerous features including: the colour of the elytra (brown in M. (M.) youweii new species; yellow-brown in M. (M.) thai), the form of the prosternal process (basiconic shaped in M. (M.) youweii new species; cone-shaped in M. (M.) thai); the quantity of thorns on dorsomedial margin of metatibia (four in M. (M.) youweii new species; three in M. (M.) thai); the form of dorsal branches of parameres (slender and curved downwards at basal 1/ 3 in M. (M.) youweii new species; thick and tapered in M. (M.) thai); and quantity and shape of the thorns on the apex of the temones in the male (a cluster of thin and short thorns in M. (M.) youweii new species; four thick thorns in M. (M.) thai).

Distribution. China (Yunnan: Dali, Honghe, Puer, Kunming, Xishuangbanna; Guizhou: Xingyi; Zhejiang: Moganshan) ( Fig. 6 ).

Etymology. It is with great pleasure that we name the new species for Mr Youwei Zhang who studied Chinese Melolonthinae taxonomy in his working life.

Chinese name. 章脊鳃金龟

Remarks. All the above mentioned specimens of M. (M.) youweii new species deposited in IZCAS were incorrectly identified as Holotrichia (Pledina) hybrida ( Moser, 1912) by Chang (1964). The two species can be separated by the form of the apex of dorsal branches of the parameres (sharp and setiferous in M. (M.) hybrida ; clavate-shaped in M. (M.) youweii new species) and the shape of the ventral branches of the parameres (tapered and curved upwards in M. (M.) hybrida ; tips vertically curved outwards in M. youweii new species).

Figures

FIGURE 4. Miridiba (M.) youweii Gao & Fang, new species, holotype (a–i) and paratype (j). a, habitus, dorsal view; b, habitus, lateral view; c, head, dorsal view; d, pronotum, dorsal view; e, antennae; f, metatibia, lateral view; g, parameres, lateral view; h, parameres, dorsal view; i, endophallus, lateral view; j, female genitalia, dorsal view. Scale bar: 5 mm for a, b, j; 1 mm for c, d, f, g, h, i; 0.5 mm for e. Ag, Accessory gland; Bc, bursa copulatrix; Gc, genital chamber; Mo, median oviduct; Ut, vestigial tergite; Us, vestigial sternite.

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