Ocyptamus myiophagus Thompson, 2018

Mengual, Ximo, Miranda, Gil Felipe G. & Thompson, F. Christian, 2018, Unraveling Ocyptamus and the Baccha legacy (Diptera: Syrphidae): redefinition of groups and new species descriptions, Zootaxa 4461 (1), pp. 1-44 : 18-19

Ocyptamus myiophagus Thompson sp. nov.

Figs 108–110 , 115.

Ocyptamus CR-36 Thompson in litt.

Ocyptamus CR-49 Thompson in litt.

Ocyptamus sp. Ureña & Hanson (2010).

Differential diagnosis. Species of the O. lepidus species group with face yellow and black pilose. Thorax broadly yellow laterally, black medially; scutellum dull yellow. Wing light brownish, completely microtrichose; alula about as wide as cell bm. Abdomen parallel-sided, dark, abdominal segment 2 rectangular (~2.5 times longer than wide) with a pair of mesolateral yellow vittate maculae, tergum 3 similar to tergum 2, and tergum 4 brown with a pair of basolateral short yellow maculae and a pair of inconspicuous medial vittae.

Description. MALE: Head ( Fig. 109 ). Face yellow, whitish microtrichose and black pilose laterally, shiny and bare medially; lunule bare, yellow laterally, black medially; frontal triangle yellow except for a narrow brown medial vitta, dull microtrichose, black pilose; vertical triangle narrow, short about 1/3 as long as eye contiguity, black, black microtrichose and pilose; gena very narrow, yellow, bare; occiput black, gray microtrichose, with thick white pile on ventral 2/3, yellow pilose dorsally arranged in a single row on dorsal 1/4. Antenna yellowish orange except apical half of basoflagellomere brown; scape and pedicel black pilose; arista bare, short about as long as antenna. Thorax ( Figs 108, 110 ). Brown and yellow; postpronotum and prothorax yellow; mesonotum dull brownish except yellow laterally from postpronotum to just posterior to transverse suture, pile sparse, short and yellow; postalar callus dull yellow, yellow pilose; pleuron dull yellow except black ventral 1/3 of katepisternum, anterior anepimeron and a broad vitta running from metathoracic spiracle to metacoxa; scutellum dull yellow, with short, sparse black pile, without ventral fringe; halter yellow with large brownish black capitulum; calypter narrow, with dorsal lobe without fringe, with ventral lobe with a conspicuous yellow fringe. Legs: Proleg yellow, pale pilose; mesoleg yellow, pale pilose except with a posterior row of black pile on femur; metaleg brown and black pilose except apex of basotarsomere and apical tarsomeres yellow and pale pilose. Wing: brownish, slightly darker anteriorly, entirely microtrichose; alula narrow, slightly wider than cell bm, microtrichose. Abdomen ( Figs 108, 110 ). Elongate, narrow, slightly narrower than thorax; terga 2 and 3 subequal, and tergum 4 about 3/4 as long as tergum 2; tergum 1 brown except yellow laterally, dull, black pilose; terga 2–3 brown except for narrow yellow mesolateral maculae, dull, black pilose; tergum 4 brown with a pair of basolateral short yellow maculae and a pair of inconspicuous medial vittae, dull, black pilose; tergum 5 brown, with four yellow vittae, dull, black pilose; sternum 1 yellow, shiny, bare; sterna 2–5 narrow, brownish, sparsely black pilose. Genitalia: as in fig. 115; with subepandrial sclerite with bilobate process between bases of surstyli.

FEMALE. Similar to male except: frons yellow with broad medial brownish black vitta, dull, black pilose; ocellar triangle situated from posterior eye margin a distance 3.5 times its length; tergum 6 brownish black.

Length (n=1). Body, 11 mm; wing, 10 mm.

Etymology. The name is derived from the Greek myio - from myia, that means fly ( Brown 1956: 543), and the Greek - phago from phagein, which means to eat ( Brown 1956: 293), and it refers to the larval biology of the species ( Ureña & Hanson 2010). Specific epithet is an adjective.

Geographical distribution. Only known from Costa Rica.

Type-locality. COSTA RICA, San José Prov. , San Pedro de Montes de Oca, Universidad de Costa Rica, 9°56'09'' N 84°03'02'' W.

Material examined. Holotype, male, deposited in the Instituto Nacional de Biodiversidad (INBio), Santo Domingo de Heredia, Costa Rica, and labelled: “Costa Rica, San José // San Pedro Montes de Oca // U.C.R. // 1200m 10/ix/2001 // Col.: Onanchi Ureña // ind.A14 ♂” “ Holotype // Ocyptamus // myiophagus / Thompson ” [light red, handwritten] ‘USNMENT // 01288295” [barcode]. Paratypes: the same locality as holotype, but different dates: x.2001, ind.L38 [1♂ UCR, ZFMK-DIP-00026907]; x.2001 [1♀ UCR, ZFMK-DIP-00026908]; ix.2001, ind.N [1♂ USNM, ZFMK-DIP-00026909]; ix.2001, ind.A13 [1♂ USNM, ZFMK-DIP-00026910]; 15.viii.2001, ind.B [1♂ ZFMK, ZFMK-DIP-00026916]; 3.ix.2001, ind.A22 [1♀ ZFMK, ZFMK-DIP-00026917]; 10.ix.2001, ind.A14 [1♂ USNM]; ix.2001, ind.A19, DNA-voucher ZFMK-D306 [1♂ ZFMK, ZFMK-DIP-00026911]; ix.2001, DNA-voucher ZFMK-D308 [1♂ ZFMK, ZFMK-DIP-00026912]; ix.2001, DNA-voucher ZFMK-D309 [1♂ UCR, ZFMK-DIP-00026914]; x.2001, ind.30, DNA-voucher ZFMK-D310 [1♀ ZFMK, ZFMK-DIP- 00027139]; ix.2001, DNA-voucher ZFMK-D317 [1♂ ZFMK, ZFMK-DIP-00026913].

Biology. Ureña & Hanson (2010) described in detail the larval biology of this species. Larvae of O. myiophagus sp. nov. are found living among whitefly nymphs ( Hemiptera : Aleyrodidae ) on the undersides of citrus leaves. Instead of feeding on the whitefly nymphs, O. myiophagus sp. nov. larvae attack and subdue, with some kind of venom, adult flies that are attracted to honeydew. Results from their study suggest that O. myiophagus sp. nov. covers its larval body with the whitefly honeydew to attract the adult flies. Under laboratory conditions, larvae feed on Drosophila melanogaster Meigen, 1830 and D. saltans Sturtevant, 1916 ( Diptera : Drosophilidae ). Ureña & Hanson (2010) also reported some kind of cannibalism when a first instar larva fed on an egg of the same species, and an unidentified coccinellid ( Coleoptera ) as predator of eggs of O. myiophagus sp. nov.. Two endoparasitic koinobionts were reported in their study for O. myiophagus sp. nov., Proaspicera sp. ( Figitidae ) and Paracarotomus sp. ( Pteromalidae ).

Comments. Based on characters of the male genitalia, and overall habitus of the adult, this species is part of the O. lepidus species group. The larval biology of this species, including camouflage, active prey attack, and its diet of adult dipterans make this species unique.

Figures

FIGURES 106–111. 106: Pelecinobaccha alicia [female, CNC], occiput, detail, photo previously published in Miranda et al. (2014): ar: anterior row of occipital pile; pr: posterior row of occipital pile. 107: Relictanum johnsoni (Curran) [female, CNC], occiput, detail, photo previously published in Miranda et al. (2014): sr: single row of occipital pile. 108: Ocyptamus myiophagus Thompson sp. nov. [male holotype, USNMENT 01288295], habitus, dorsal view. Scale = 1 mm. 109: Ocyptamus myiophagus Thompson sp. nov. [male holotype, USNMENT 01288295], head, frontal view. Scale = 1 mm. 110: Ocyptamus myiophagus Thompson sp. nov. [male holotype, USNMENT 01288295], habitus, lateral view. Scale = 1 mm. 111: Syrphus sargoides [male, GFGM-MNRJ0002], hypandrium, lateral view.