Citrogramma asombrosum, Mengual, 2012

Mengual, Ximo, 2012, The flower fly genus Citrogramma Vockeroth (Diptera: Syrphidae): illustrated revision with descriptions of new species, Zoological Journal of the Linnean Society 164 (1), pp. 99-172 : 128-129

CITROGRAMMA ASOMBROSUM MENGUAL SP. NOV.

Description

Male: Head: Face with facial tubercle, gradually sloping dorsally, more abrupt ventrally, yellow with medial dark vitta, from oral apex to antennal base, narrower than yellow lateral areas of face, yellow pilose, black pilose laterodorsally; gena yellow, yellow pilose; holoptic; lunule yellow; frontal triangle yellow with anteromedial black diffuse triangular area pointed posteriorly, black pilose; vertical triangle black, black pilose; ocelli reddish; antenna dark brown, black pilose on scape and pedicel; basoflagellomere orangish, dark dorsally; arista brown; occiput black, silver pollinose, white pilose on ventral two thirds, golden-yellow pilose on dorsal third.

Thorax: Scutum black with dorsomedial area uniformly grey pollinose with bluish metallic iridescence, lateral yellow vitta and sublateral matte black vitta, black and yellow pilose, but notopleuron yellow pilose with some black hairs posteriorly; postpronotum yellow; notopleuron yellow continuing until scutellum, with postalar callus entirely yellow and black pilose; scutellum yellow with dorsomedial broad defined dark macula not reaching anterior margin, creating narrow yellow margin all around, black pilose, subscutellar fringe complete with black hairs. Pleuron mostly black, except anterior anepisternum yellow; proepisternum yellow; posterior anepisternum yellow on posterior half; katepisternum with dorsal yellow macula; katepimeron and katatergum yellow, black posteriorly. Pleuron entirely yellow pilose, golden pollinose. Metasternum pilose; calypter yellow with brownish hairs on margin; plumula yellow; halter yellow; spiracular fringes yellow.

Wing: Wing membrane brownish, entirely microtrichose. Alula microtrichose, broad, broader than cell BM.

Legs: Procoxa yellow, mesocoxa black, metacoxa yellowish brown; pro- and mesofemur black dorsally (exterior part of metafemur) and yellowish ventrally (inner part of metafemur), mainly black pilose with yellow hairs basally; pro- and mesotibia yellow; pro- and mesotarsus brown; metaleg black, metafemur slightly swollen, black pilose.

Abdomen: Figure 17 . Parallel-sided, abdominal margin partly visible on terga 4 and 5. Dorsum mainly black, black pilose dorsally and laterally except tergum 1 yellow pilose laterally and tergum 2 yellow pilose laterally on anterobasal half; tergum 1 black; tergum 2 black with two mesolateral triangular rounded-tip yellow maculae, yellow lateral margin on anterior half; terga 3 and 4 black with broad yellow fascia (about one third to two fifths of tergum length) on anterior half of tergum, with anterior narrow black fascia; tergum 5 black with medial narrow yellow fascia; sterna yellow, yellow pilose with black hairs laterally except terga 3 and 4 black on posterior half, tergum 4 black pilose, with posterior margin emarginate on right side to accommodate genitalia; tergum 5 reduced; genital segments brownish, sternum 7 with anterior small projection and posterior small projection, sternum 8 with posterolateral large projection; male genitalia broad, as in Figures 135–137 .

Female: Unknown.

Length (N = 1): Body, 8.1 mm; wing, 7.8 mm.

Geographical distribution: New Caledonia.

Etymology: The specific epithet is derived from the Spanish asombroso meaning amazing, astonishing. This refers to the surprising male genitalia of this species. Species epithet to be treated as an adjective.

Ecology: Holotype collected in a Malaise trap set in tropical forest habitat.

Differential diagnosis: Very distinctive species with black facial vitta, costal cell microtrichose, scutellum with a medial black macula not reaching anterior margin, and large male genitalia with processes on terga 7 and 8. Citrogramma asombrosum is similar to C. bicornutum , but C. asombrosum has cell BM bare only very basally, cell CuP is entirely microtrichose and yellow abdominal fasciae are broader than in C. bicornutum . Moreover, C. bicornutum has no process on terga 7 and 8.

Remarks: Species known only from the holotype male. This species is placed in two positions in the identification key because the bare area of the wing is small, and may be misinterpreted.

Holotype male deposited in the Illinois Natural History Survey (Champaign, Illinois, USA) and labelled: ‘ NEW CALEDONIA /Mt Khogis, 500 m / 17 km NNE Nouméa/ 30–31 Oct. 1992 /MEIrwin, DWWebb’ ‘Malaise Trap/in tropical/forest’ ‘Illinois Nat. Hist. Survey’ ‘ HOLOTYPE / Citrogramma / asombrosum /det. X. Mengual 20 09 ’ [red, second and third lines handwritten].

Type locality: New Caledonia: South Province, Nouméa, Mount Koghi (also spelled Koghis), 500 m, 22°12′S, 166°30′E .

Material examined: Type material. Holotype, as above.

Figures

Figures 15–26. Dorsal view of abdomen. 15–16, Citrogramma bicornutum: 15, female; 16, male. 17, Citrogramma asombrosum, male. 18–19, Citrogramma quadratum: 18, male; 19, female. 20–21, Citrogramma arisanicum: 20, male; 21, female. 22, Citrogramma australe, male. 23–24, Citrogramma notiale: 22, female; 24, male. 25–26, Citrogramma robertsi: 25, female; 26, male.

Figures 131–139. 131–134, microtrichia pattern of wing. 131, Citrogramma pendleburyi. 132, Citrogramma marissa. 133, Citrogramma clarum. 134, Citrogramma sp. B. 135–137, Citrogramma asombrosum, male genitalia: 135, left lateral view; 136, tergum 9 and surstyli, dorsal view; 137, terga 7, 8, and 9, and surstyli, lateroventral view (as in pinned specimen). 138–139, Citrogramma australe: 138, left lateral view; 139, tergum 9 and surstyli, dorsal view.