Biema Huo & Zhao, 2022

Huo, Ke-Ke, Zhao, Le, Mengual, Ximo, Li, Gang, Liu, Xin, Zhao, Lian-Jun & Chen, Zhen-Ning, 2022, Biema Huo & Zhao gen. nov., a new flower fly genus (Diptera, Syrphidae) from China, European Journal of Taxonomy 852, pp. 98-116 : 101-102

Genus Biema Huo & Zhao gen. nov.

urn:lsid:zoobank.org:act:A0AF4F68-7FD0-454A-B850-61565DD303DC

Type species

Biema wanglangensis Huo & Zhao gen. et sp. nov.

Diagnosis

Biema gen. nov. can be distinguished by the following morphological features: head deeply concave posteriorly with a concealed postpronotum; postpronotum without pile; head, mesonotum and scutellum black; metasternum not reduced, with posterior margin shallowly concave similar to that in Platycheirus Le Peletier & Serville, 1828 ; alula narrow, as wide as basal width of cell c; male postabdomen conspicuous more swollen than other segments, surstylus and postgonite complex, phallus unsegmented. In the identification key to bacchine and melanostomine groups by Thompson & Skevington (2014), the new genus keys out to couplet 2. Further, males of Biema key out to Baccha Fabricius, 1805 based on its short pilose antennal arista, unmodified hind tibia, distinct facial tubercle and bare metathoracic pleuron. Our new genus can be easily distinguished from Baccha by the incomplete postmetacoxal bridge (complete postmetacoxal bridge in Baccha ) and by the sparse but present scutellar fringe (absent in Baccha ). Females of Biema , with a parallel-sided abdomen, key out to couplet 11 and are morphologically related to Platycheirus , Argentinomyia Lynch-Arribálzaga, 1891 and Melanostoma .

Etymology

The new genus is named after the Biema Zang people, who live where the type specimens were collected.

Description

Small sized flies. Head hemispherical. Eye bare. Vertex, frons and face black, densely white pollinose obscures ground colour. Facial tubercle rounded and produced, bare and shinning. Arista extremely short pilose. Antennal sockets confluent. Scutellum black, row of short bristles on posterior margin and one pair of bristles elongated in the middle. Katepisternum only with ventral patches. Metasternum not reduced, posterior margin shallowly concave similar to that in Platycheirus . Legs slender, not modified, hide-coxa without tuft of pile on anteromedial corner. Wing membrane entirely microtrichose. Vein R 4+5 straight; spurious vein rudimentary; crossvein r-m slightly inclined, located before basal ⅓ of cell dm; alula narrow, as wide as width of cell c. Male abdomen nearly parallel-sided, slightly constricted at tergite 2 posterior margin, broadened from tergite 3 and widest part at end of tergite 4, postabdomen conspicuous more swollen than other segments. Tergite 2 slightly longer than tergite 3, and tergite 3 slightly longer than tergite 4. Abdomen blackish brown with yellow maculae or fasciae. Male surstylus and postgonite complex, phallus unsegmented.

Biology and distribution

Biema gen. nov. occurs in forest areas, at or above 2300 m altitude in China (Sichuan, Qinghai) ( Fig. 1 ).

Figures

Fig. 1. Known distribution of genus Biema Huo & Zhao gen. nov. in China. Pink dot represents Biema qilianensis Huo & Liu gen. et sp. nov.; black dot represents Biema wanglangensis Huo & Zhao gen. et sp. nov.; pink area represents Sichuan Province, China; grey area represents Qinghai Province, China.