Asiobaccha selsi Mengual

Mengual, Ximo, 2016, A taxonomic revision of the genus Asiobaccha Violovitsh (Diptera: Syrphidae), Journal of Natural History 50, pp. 2585-2645 : 2625-2628

Asiobaccha selsi Mengual sp. nov.

( Figure 10a, b, f )

Description

Male: Head. Face with distinct facial tubercle, darkened, brown, yellow pilose, white pollinose laterally and bare medially; gena brown; lunule yellow becoming black dorsally, yellow also between antennal bases; frons black, black pilose, pale pollinose laterally and posteriorly, shiny medially; vertical triangle narrow, isosceles, with the ocelli on the anterior half, black, black pilose; antenna yellow, basoflagellomere brown dorsally, black pilose; arista brown, bare; eye bare, holoptic; occiput black, grey-silver pollinose, pale pilose on ventral 2/3 and dark pilose on dorsal 1/3 ( Figure 10f ).

Thorax. Scutum black, laterally pale pollinose, scarcely black pilose; without mesonotal fringe on anterior part of scutum; postpronotum light brown, bare; notopleuron brown, densely white pollinose, pale pilose; postalar callus brown; scutellum yellowish brown, yellow pilose, subscutellar fringe absent ( Figure 10a, b ). Pleuron mostly brown to light brown, densely white pollinose, pale pilose; metaepisternum yellow pilose ventrad to spiracle; metasternum bare; calypter small, reduced, yellow; plumula small, yellow; halter: pedicel brown, capitulum black; posterior spiracular fringes yellow. Wing: alula absent, anal lobe reduced. Wing membrane infuscated, brown; extensively bare basomedially: cells C and R microtrichose only on apical 1/5 or less, cells BM and CuP bare with a few microtrichia apically, and cell CuA1 and anal lobe bare basally. Legs: mostly yellow, yellow pilose, except metafemur and metatibia with some dark pile.

Abdomen. Petiolate, unmargined. Dark, with no clear markings; terga 3 and 5 lighter basally, and terga 2 – 4 scattered dark pollinose on apical 1/2. Entirely black pilose except tergum 1 with long, thick pale pile on lateral sides ( Figure 10a, b ). Male genitalia dark.

Female. Similar to male except for normal sexual dimorphism and as follows: gena yellow, frons black, shiny, white pollinose only laterally, pale and dark pilose. Abdomen dark, black pollinose on apical 1/5 on tergum 2, and on apical 1/3 – 1/2 on terga 3 to 5; the area not covered by the black pollinosity is bluish grey, pale pollinose.

Variation. Face is variable between light brown to brown. Some specimens are lighter having scutellum yellowish and lateral margins of the scutum light brown; others have the scutellum dark brown. In some female specimens the abdominal area not covered by the black pollinosity is lighter without becoming yellow or orange. Thus, the abdomen is dark in general, but paler colouration might appear due to preservation/drying conditions.

Length (N = 5). Body, 11.0 – 12.5 (11.8) mm; wing, 10.0 – 12.0 (10.6) mm.

Geographical distribution

Species known only from New Guinea.

Etymology

This species is named after all of my colleagues at the Systematic Entomology Laboratory, Agricultural Research Service, United States Department of Agriculture (SEL), and all my colleagues and friends at the Entomology Department of the USNM, Smithsonian Institution (SI). The name is a combination of letters (acronyms SEL + SI) and is to be treated as a noun in apposition.

Differential diagnosis

Asiobaccha selsi has no alula and a reduced anal lobe of the wing. This species is darker than other species without alula, with tergum 1 dark and most of the abdomen without clear pale markings. Asiobaccha selsi differs from other species without alula by having the wing cell C almost completely bare, microtrichose on apical 1/5 or less.

Type locality

Papua New Guinea: Morobe Province, Bulolo district , NE Wau , n. 1700 m, 07°16 ’ S, 146°46 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 ].

Remarks

Male genitalia of populations from Indonesia and Papua New Guinea do not show any difference between them. Specimens from the collection at RMNH have a manuscript name given by P. H. van Doesburg, Baccha fumipennis , which was never published; thus, it is not available.

Figures

Figure 10. Asiobaccha selsi Mengual sp.nov. a–b, f, holotype ♂. (a) Dorsal view; (b) lateral view; (f) frontal view. Asiobaccha taronja Mengual sp. nov. c–e, g, holotype ♂. (c) Dorsal view; (d) abdominal sterna and male genitalia, ventral view; (e) lateral view; (g) frontal view. Scale bars: a–c, e = 2 mm; d, f, g = 1 mm.