Asiobaccha taronja Mengual

Mengual, Ximo, 2016, A taxonomic revision of the genus Asiobaccha Violovitsh (Diptera: Syrphidae), Journal of Natural History 50, pp. 2585-2645 : 2628-2629

Asiobaccha taronja Mengual sp. nov.

( Figures 10c, d, e, g , 13c, d )

Description

Male: Head. Face narrow with distinct facial tubercle, yellow, yellow pilose, yellow pollinose except tubercle shiny; gena narrow, yellow; lunule yellow, shiny; frons yellow ventrally, mostly black, pale pilose, white-silver pollinose laterally and dorsally, shiny basomedially dorsad to lunule; vertical triangle narrow, black; antenna yellow, yellow pilose; arista brown, yellow basally, bare; eye bare; occiput very narrow, black, whitesilver pollinose, entirely yellow pilose ( Figure 10g ).

Thorax. Entirely orange-yellow; scutum orange pollinose medially, with almost no pile; without mesonotal fringe; scutellum yellow, yellow pilose, subscutellar fringe absent ( Figure 10c ). Pleuron yellow pollinose; anterior anepisternum almost bare, with a few short, yellow pile; metaepisternum pilose ventrad to spiracle; metasternum bare; calypter small, reduced, orange-yellow; plumula absent; halter pedicel orange, capitulum dark; posterior spiracular fringes orange ( Figure 10e ). Wing: alula narrow, narrower than costal cell, bare; anal lobe reduced. Wing membrane hyaline, stigma yellow, extensively microtrichose except cell BM bare on basal 2/3, cell R bare on basal 1/3, and cells CuP and anal lobe basally. Legs: entirely orange-yellow.

Abdomen. Petiolate, unmargined, mainly black pilose except tergum 1 pale pilose and tergum 2 pale pilose medially and basally. Tergum 1 orange-yellow; tergum 2 orangeyellow with a brownish fascia on posterior margin; tergum 3 orange yellow on anterior 2/3, darker posteriorly; tergum 4 black with a yellow fascia on anterior 1/4, tergum 5 black ( Figure 10c, e ); sterna orange-yellow except sternum 4 black on posterior 1/2; male genitalia yellow, large, with epandrium and hypandrium enclosed under sternum 4, epandrium with a posterodorsal elongation and surstylus placed posteromedially, superior lobes expanded laterally ( Figures 10d , 13c, d ).

Female. Unknown.

Variation. The holotype has tergum 3 darker, and the paratype male misses the head.

Length (N = 1). Body, 14.0 mm; wing, 13.0 mm.

Geographical distribution

Species known only from Solomon Islands.

Etymology

The specific epithet is derived from the Catalan taronja meaning orange. Species epithet is to be treated as adjective.

Differential diagnosis

This species is very distinct, mostly orange-yellow with terminal terga black, with a broad head and a narrow face, and very large male genitalia, unique among other species of this genus ( Figure 13c, d ). Asiobaccha taronja belongs to a species group with pale markings on abdomen, narrow alula, and without mesonotal fringe, which occur from Indonesia south and eastwards. This species has a short and robust abdominal pedicel (tergum 2) compared with the species group with mesonotal fringe (e.g. A. virtuosa and A. nubilipennis , among others) and it is very easy to distinguish from other species, such as A. marissae and A. bicolor , by the large male genitalia and the overall body colouration, especially the orange mesonotum.

Type locality

Solomon Islands: Guadalcanal Province, Paripao , 09°33 ′ S, 160°20 ′ E.

Material examined

Type material. Holotype, male, deposited in the Bernice P. Bishop Museum (Honolulu, Hawaii, USA) and labelled: ‘ SOLOMON IS. // Guadalcanal // Paripao , 22 May ′ 60 ’ ‘C. W. O ′ Brien // Collector ’ ‘ HOLOTYPE // Asiobaccha // taronja // des. X. Mengual 2014’ [red; second and third lines handwritten] (specimen photographed). Paratypes: SOLOMON ISLANDS: Isabel Prov., Santa Isabel Island, Molao , 29 June 1960, C.W. O ′ Brien [1♂, ZFMK, ZFMKDIP 00011949].

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.

Figure 13. Asiobaccha nubilipennis (Austen). a–b, ♂, male genitalia. (a) Lateral view; (b) ventral view. Asiobaccha taronja Mengual sp. nov. c–d, paratype ♂, male genitalia. (c) Lateral view; (d) ventral view. Scale bars = 0.5 mm.