Microdon dentigiganteum Tian, Huo et Zhang, 2019

Tian, Jing, Huo, Ke-Ke, Zhang, Chun-Tian & Ren, Bing-Zhong, 2019, Microdon dentigiganteum sp. nov. and other Microdontinae species (Diptera: Syrphidae) from Northeast China, Zootaxa 4712 (1), pp. 65-76 : 66-67

Description of Microdon dentigiganteum Tian, Huo et Zhang , sp. nov.

( Figs 2 , 3 , 4 , 5D )

Diagnosis. Lateral oral margins not produced. Scutellum with large size calcars. Propleuron pilose. Basotarsomere of legs about 2 times as wide as apex of tibiae. Postero-apical corner of cell r 4+5 rounded. Apical crossvein M 1 with a small inward appendix extending into cell r 4+ 5 in some specimens ( Fig. 3H ). Length ratio of terga III:IV is about 1:2. Aedeagus projecting conspicuously beyond apex of hypandrium, furcate close to base, with dorsal process slightly longer than ventral process.

This species keys out to Microdon japonicus Yano, 1915 in the keys of Hironaga & Maruyama (2004) and Huo et al. (2007). The new species can be separated from M. japonicus by the entirely yellow pilose terga (partly black pilose in M. japonicus ) and the black tibiae (basal 2/3 yellowish white in M. japonicus ).

MALE (Holotype). Body length: 12mm. Head: Roughly oval in frontal view ( Fig. 2B ), almost as wide as mesonotum. Eyes bare. Vertex and frons shining black, yellow pilose, the width of the vertex at the posterior margin of eyes is about 34% of head width. Eye margins converging at level of frons ( Fig. 3B ), with mutual distance about 57% width of posterior margin of vertex. Occiput widened, black, yellowish pilose, with gray white pollinosity. Face almost straight in profile; about equal to the width of the posterior margin of vertex; shining black and punctate, long yellowish pilose. Lateral oral margins not produced. Gena black, yellowish pilose. Antennal pits about as wide as high. Antenna black; antennal ratio approximately 4.8: 1: 4.2; arista bare, yellow, about as long as the basoflagellomere. Thorax: Scutum shining black with green hues, punctate, yellowish pilose. Scutellum dark orange, except anterior margin which is widely black with green hues; yellowish pilose; with deeply concave posterior margin; with huge posterolateral calcars conspicuously longer than 1/2 of the scutellum length. Pleuron shining black with green hues, punctate; all pile yellow.Anepisternum ( Fig. 2D ) pilose anteriorly and posterodorsally, with widely bare part in between, which nearly reaches anepisternum dorsally. Anepimeron pilose anteriorly. Katepisternum pilose posterodorsally; bare ventrally. Katatergum long yellowish-brown microtrichose. Metasternum yellow pilose. Wing: Hyaline, vein yellow; microtrichose; vein R 4+5 with appendix; vein M 1 more and less straight, perpendicular to vein R 4+5; postero-apical corner of cell r 4+5 rounded, without appendix; crossvein r-m located basal 1/4 of cell dm. Calypter and halter yellow. Legs: Black, except for dark brown tarsomeres 1–3 and brown tarsi 4–5; yellow pilose, except for brown pilose on tarsi. Tarsi are very wide and flat. Abdomen: Broadly oval, tapering, about 1.5× the width of thorax. Lateral margin of terga II–IV thickened and bent downward. Abdomen black, except posterior part of tergum IV and sternum IV which are more or less red-brown, with green hues, punctate, yellow pilose. Length ratio of terga II–IV about 1: 2: 4. Genitalia ( Fig. 4 ): Aedeagus projecting conspicuously beyond apex of hypandrium, furcate near its base, with dorsal process slightly longer than ventral process; surstylus knife-shaped (lateral view), with a short and wide lobe at ventral margin (see Fig. 4B , arrows), punctured; cercus roughly triangular.

FEMALE. Body length: 14mm. Similar to male, except for the following differences: Face equal to width of frons and vertex, occupying about 40% of head width in frontal view. Length of tergum IV approximately equal to tergum V.

Type material. HOLOTYPE: 1 ♂, CHINA, Qianshan, 450~ 550 m, Anshan , Liaoning province, 21–23.vi.2006, leg. Y.-N. Zhao ( NENU) . PARATYPES (3): 2 ♂, 1 ♀ CHINA, Qianshan, 450~ 550 m, Anshan , Liaoning province, 21–23.vi.2006, leg. X. Xing / J. Zhang / M. Cai ( NENU) .

Etymology. The specific epithet is composed of the Latin words denti (tooth) and giganteum (great), and refers to the huge calcars on posterior margin of scutellum.

Distribution. China (Liaoning province).

Figures

FIGURE 2. Microdon dentigiganteum Tian, Huo et Zhang, sp. nov., male holotype. (A) Habitus, dorsal view; (B) Habitus, lateral view; (C) Abdomen; (D) Anepisternum. Scale bars: a, b, c = 5mm; d = 1mm.

FIGURE 3. Microdon dentigiganteum Tian, Huo et Zhang, sp. nov. (A) Male head, lateral view; (B) Male head, dorsal view; (C) Female head, frontal view; (D) Female head, dorsal view; (E) Male scutellum; (F) Male antenna, dorsal view; (G) Wing; (H) Apex part of wing.

FIGURE 4. Male genitalia of Microdon dentigiganteum Tian, Huo et Zhang, sp. nov.. (A) lateral view; (B) ventral view. Abbreviations: aed, aedeagus; aed apod, aedeagal apodeme; cerc, cercus; epand, epandrium; hypd, hypandrium; sur, surstylus. Scale bars: 1mm.

FIGURE 5. Antennae of adult Microdontinae from Northeast China. (A) Metadon spuribifasciatus, female; (B) Microdon analis, male; (C) Microdon auricomus, female; (D) Microdon dentigiganteum sp. nov., male; (E) Microdon ignotus, male; (F) Microdon oitanus, male. Scale bar: 1mm.