Miridiba (Miridiba) taipei Wang & Li

Li, Chun-Lin, Yang, Ping-Shih & Wang, Chuan-Chan, 2015, A review of the genus Miridiba Reitter (Coleoptera: Scarabaeidae: Melolonthinae) of Taiwan, Zootaxa 3955 (4), pp. 521-536 : 530-532

Miridiba (Miridiba) taipei Wang & Li , new species

Figs. 5 , 11 , 17, 23, 33, 34

Males ( Fig. 5 ). Body length 14.1–15.5 mm; width across humeri 7.1–8.0 mm. Color reddish brown to rufotestaceous on head, pronotum, scutellum, legs, and ventral thorax; yellowish brown on elytra and abdomen; moderately shiny. Antennae yellowish brown or reddish brown. Pronotum and elytra (Fig. 17) densely covered with hair-like, long, brownish pale setae; longest setae reaching 2 mm in length; setae on frons half as short as those on pronotum; dorsal surface of clypeus and scutellum glabrous. Head: Surface densely punctate; punctures large, deep, each bearing an erect seta. Clypeus ( Fig. 11 ) with apex moderately bilobed and reflexed, widened at base. Clypeofrontal suture clearly defined. Basal carina straight, distinctly raised. Antenna with 9 antennomeres, club subequal to length of antennomeres 1–6 combined. Thorax: Pronotum widest at middle, anterolateral angles moderately protuberant ( Fig. 11 ), basolateral angles obtuse, lateral margin coarsely serrate, moderately reflexed; lateral declivities without gibbosity, gradually declined; anterior margin completely beaded, with basal margin smooth; setiferous punctures shallower and sparser than punctures on clypeus, rarely confluent. Scutellum triangular, flat; punctures smaller and shallower than punctures on pronotum. Prosternal process tongue-like, slightly raised apically. Elytra: Discal surface densely rugopunctate; sutural costa with same width from base to tip. Abdomen: Pygidium wider than long; discal surface with moderately dense, setiferous punctures; setae of varying length intermixed all over disc, longest seta about 7 times longer than shortest setae. Sternites 1, 2, 5, and 6 densely punctate; sternites 3 and 4 moderately densely punctate, punctures shallow and setiferous, setae short; sternites 5–6 with setae intermixed with setae 2–8 times longer. Legs: Protibia tridentate. Profemora, mesofemora, and metafemora ( Fig. 23 ) sparsely covered with long, hair-like setae; metafemora slender, slightly broadened at middle, not convex. Metatibia upper spur reaching basal one-third of second tarsomere. Genitalia: Parameres with upper part smoothly curved downwardly below lower part in lateral view (indicated by two-headed arrow in Fig. 33 ); parameres with apex of upper part bent laterally (indicated by arrow in Fig. 34 ).

Female. Body length 15.0 mm; width across humeri 7.8 mm. Antennal club shorter than in male, subequal to length of antennomeres 2–6 combined. Dorsal setae generally shorter than in males.

Diagnosis. See diagnosis of M. taoi for comparison of similar Miridiba species in Taiwan. Type material. The male holotype is pinned and with the following information on the label: Taipei County: Lin Ko, 8-II-1990, I.-S. Hsu (deposited at NMNS). TAIWAN. Taipei City: Taipei Botanical Garden, 17-III-1967, I.-L.Yang. (5 males, 1 female, TFRI); Taihoku (presently Taipei City), 30/III/1934, Col. S. Sakamoto (1 male, CCLI).

Distribution. Northern Taiwan ( Taipei area) ( Fig. 43 ).

Etymology. The specific name refers to the type locality, Taipei , which is the only known locality of the new species.

Chinese name. 台北脊頭鰓金龜

Remarks. Miridiba taipei is the first species of the genus to appear, although rarely, in early spring. According to available collecting records, M. taipei only occurs in the Greater Taipei area. Since this is an urbanized part of Taiwan, the population status is in need of study.

Itoh (2001) described a morphologically close species, M. hirsuta , from Ishigakijima, a small island located approximately 250 km east of Taiwan. Coca-Abia (2008) suspected that M. hirsuta was a synonym of M. trichophora , another species similar to M. taipei , but took no nomenclatural action because she could not examine the types of M. hirsuta . Recently, we obtained a pair of the paratypes (1 male and 1 female) of M. hirsuta and a series of M. trichophora (3 males and 4 females) collected from China, which enabled us to compare those three similar species in detail. Diagnostically, there are three major morphological characters that separate them: the apex of clypeus, the anterior margin of pronotum, and the parameres. First of all, M. trichophora has its anterior margin of clypeus almost flat ( Fig. 41 ) compared to the distinctly bilobed apex in both M. hirsuta ( Fig. 42 ) and M. taipei ( Fig. 11 ). For the anterolateral angles of pronotum, it is strongly protuberant with anterior margin roundly concave in M. trichophora (indicated by arrow in Fig. 41 ), moderately protuberant with obtusely curved anterior margin in M. taipei ( Fig. 11 ), and weakly protuberant in M. hirsuta ( Fig. 42 ). The parameres of M. taipei have the tip of the upper part prolonged (both in lateral ( Fig. 33 ) and dorsal ( Fig. 34 ) view) and smoothly curved downwardly below the lower part ( Fig. 33 ), in contrast to M. trichophora where the tip of the upper part is not prolonged ( Figs. 35, 36 ) and not extending beyond lower part ( Fig. 35 , indicated by two-headed arrow). Unlike the two above-mentioned species with smoothly curved parameres, M. hirsuta has two reflex points along the outer margin of the upper part ( Fig. 37 ) that are easily distinguishable. In addition, M. hirsuta has a row of setae in outer margin of parameres when viewed dorsally ( Fig. 38 ).

Figures

FIGURE 43. Distribution map of Miridiba species in Taiwan: Miridiba kuraruana (open circle), Miridiba formosana (open triangle), Miridiba taipei (black diamond), Miridiba sinensis (open square), and Miridiba huesiotoi and Miridiba taoi indicated by arrow, respectively.

FIGURES 1 – 6. Dorsal habitus of male Miridiba species. 1. Miridiba kuraruana; 2. Miridiba huesiotoi, holotype; 3. Miridiba taoi, holotype; 4. Miridiba formosana; 5. Miridiba taipei, holotype; 6. Miridiba sinensis.

FIGURES 7 – 12. Dorsal view of head and upper half of pronotum of male Miridiba species. 7. Miridiba kuraruana; 8. Miridiba huesiotoi, holotype; 9. Miridiba taoi, holotype; 10. Miridiba formosana; 11. Miridiba taipei, holotype; 12. Miridiba sinensis.

FIGURES 19 – 24. Right metafemur of male Miridiba species. 19. Miridiba kuraruana; 20. Miridiba huesiotoi, n. sp.; 21. Miridiba taoi, n. sp.; 22. Miridiba formosana; 23. Miridiba taipei, n. sp.; 24. Miridiba sinensis.

FIGURES 33 – 40. Parameres of Miridiba species (33, 35, 37, 39, lateral view; 34, 36, 38, 40, dorsal view). 33 – 34. Miridiba taipei; 35 – 36. Miridiba trichophora; 37 – 38. Miridiba hirsute; 39 – 40. Miridiba sinensis. Scale bar = 1.0 mm.

FIGURES 41 – 42. Head and pronotal anterior margin of Miridiba trichophora (Fig. 41) and Miridiba hirsuta (Fig. 42).