Asiobaccha albipeza Mengual

Mengual, Ximo, 2016, A taxonomic revision of the genus Asiobaccha Violovitsh (Diptera: Syrphidae), Journal of Natural History 50, pp. 2585-2645 : 2592-2594

Asiobaccha albipeza Mengual sp. nov.

( Figure 3c, d, f )

Description

Male: Head. Face flat with distinct facial tubercle, tawny (yellow-brown), white pilose, white pollinose laterally and shiny (bare) medially on tubercle; gena yellow-brown ( Figure 3f ); lunule dark; frons slightly protruded forward, black, black pilose, pale pollinose laterally and dorsally, shiny basomedially; vertical triangle narrow, isosceles, black; antenna yellow-brown, black pilose; arista brown, bare; eye bare; occiput black, white-silver pollinose, yellow pilose on ventral 3/4 and dark pilose on dorsal 1/4.

Thorax. Scutum black with bluish iridescence, medially brown pollinose, with short and scarce black pile; mesonotal fringe well-defined on anterior part of scutum, with white pile; postpronotum black, bare, white pollinose; notopleuron black, white pollinose; scutellum black, black pilose, subscutellar fringe absent ( Figure 3c, d ). Pleuron black, pale pilose, anterior anepisternum with pale pile on anterodorsal quarter; densely pale pollinose on posterior anepisternum, dorsal katepisternum and katatergum; metaepisternum pilose ventrad to spiracle; metasternum bare; calypter small, reduced, yellow; plumula almost absent, pale; halter brown; posterior spiracular fringes yellow. Wing: alula narrow, slightly broader than costal cell apically, triangular, bare with some microtrichia anteroapically. Wing membrane hyaline, stigma brown and costal cell brownish; extensively microtrichose, except cell R bare posterobasally before RS furcation, cell BM bare on basal 3/4, and cell CuP and anal lobe bare on basal 1/3. Legs: entirely brown except tarsi; pro- and mesotarsi white-yellow except basotarsomere brown on basal 1/2, metatarsus white-yellow except basotarsomere dark on basal 1/5 or less.

Abdomen. Petiolate, unmargined, black with bluish iridescence, mainly black pilose except tergum 1 pale pilose, with a black pollinose pattern as follows: terga 2 – 4 with a black pollinose fascia on posterior margin, tergum 2 also with a narrow basal fascia and a medial, small macula of black pollinosity ( Figure 3c, d ); sterna 2 – 4 black with bluish iridescence with a black pollinose fascia on posterior margin; male genitalia black.

Female. Similar to male except for normal sexual dimorphism and as follows: frons black, shiny, with white pollinosity on eye margin until half-way between antennal insertion and anterior ocellus; ocellar triangle black, shiny.

Variation. Some paler specimens have pro- and mesofemora yellowish on apical 1/2 and pro- and mesotibiae yellowish on basal 1/2. Other specimens may have a darker face.

Length (N = 4). Body, 12.5 – 15.2 (14.2) mm; wing, 11.0 – 13.0 (12.5) mm.

Geographical distribution

Species known from Solomon Islands archipelago, including Bougainville Island.

Etymology

The specific epithet is derived from the Latin albus meaning white ( Brown 1956, p. 77) and the Greek peza meaning foot ( Brown 1956, p. 343), and it refers to the white metatarsi. Species epithet is to be treated as adjective.

Differential diagnosis

Species with the alula narrower than cell BM, and with the abdomen and the scutellum dark, without pale markings. It can be distinguished from A. praefica and A. samoaensis by the narrow alula and the white metatarsus.

Type locality

Solomon Islands: Guadalcanal Province, Gold Ridge-Suta, Mount Chaunapaho (= Jonapau), 1100 m, 9°38 ’ S, 160°06 ʹ E .

Material examined

Type material. Holotype, male, deposited in the Bernice P. Bishop Museum (Honolulu, Hawaii, USA) and labelled: ‘ SOLOMON IS. // Guadalcanal: Gold // Ridge-Suta // ( Jonapau ) 1100 m. // VI-26-1956 ’, ‘ J. L. Gressitt // Collector ’, ‘ HOLOTYPE // Asiobaccha // albipeza // des. X. Mengual 2014’ [red] (specimen photographed). Paratypes: PAPUA NEW GUINEA: Bougaineville Prov., Kokure , 690 m, 8 June 1956, E.J. Ford, Jr. [1♀, BPBM];..., Togerao, 600 m, 15 – 21 April 1968, Malaise trap, R. Straatman [1♀, ZFMK, ZFMKDIP 00011907]. SOLOMON ISLANDS: Isabel Prov., Molao, 30 June 1960, C.W. O ’ Brien [1♂, BPBM]; Makira-Ulawa Prov., Makira (= San Cristóbal), Napagiwae, 19 August 1960, C.W. O ’ Brien [1♀, BPBM]; Guadalcanal Prov., Suta , 500 – 1200 m, 27 June 1956, J. L. Gressitt [1♂, ZFMK, ZFMKDIP 00011904].

Figures

Figure 3. Asiobaccha aea Mengual & Thompson sp. nov. a–b, e, holotype ♂. (a) Dorsal view; (b) lateral view; (e) frontal view. Asiobaccha albipeza Mengual sp. nov. c–d, f, holotype ♂. (c) Dorsal view; (d) lateral view; (f) frontal view. Scale bars: a–d = 2 mm; e, f = 1 mm.