Myiotabanus muscoideus (Hine, 1907)

Krolow, Tiago Kütter, Bayless, Keith M. & Henriques, Augusto Loureiro, 2012, Newly discovered males and new records of the uncommon Neotropical genera Eutabanus Kröber and Myiotabanus Lutz (Diptera: Tabanidae), Zootaxa 3389, pp. 25-33 : 30-32

Myiotabanus muscoideus (Hine, 1907)

( Fig. 3 . A–G male, H–J female)

Refs.— Kröber, 1934: 312 (cat.; Tabanus ( Tabanus )); Fairchild, 1971: 51 (cat.); Philip, 1971: 285; Fairchild & Burger, 1994: 81 (cat.); Rafael & Ferreira, 2004: 329, figs. 7–8; Coscarón & Papavero, 2009: 97 (cat.). muscoides Moucha, 1976: 193 (cat.), error.

Diagnosis: Mimetic of Sarcophagidae ; scutum with black and white stripes, dorsocentral white stripes widest. Antennal flagellomere yellow brown. Labellum partially sclerotized. Abdomen with posterior bands of light triangles. Wing predominantly hyaline.

Male. Body ( Fig. 3 A) length (without antennae) 8.1. mm, wing length 7.3 mm. Head: Holoptic eyes ( Fig. 3 B), glabrous, dark-reddish (dried specimen), largest ommatidia occupy upper 2/3 and smallest ommatidia the lower 1/ 3, with clear demarcation at limit on the height of frontal triangle; ocellar tubercle not prominent; frontal triangle with whitish pruinescence; subcallus with white pruinescence, without pilosity; gena, parafacial and face with white pruinescence and pilosity. Palpus prorrect, yellow with white pilosity and fewer than 5 black setulae. Antenna ( Fig. 3 C); scape with white pruinescence and black and white pilosity, black pilosity denser dorsally; pedicel yellow-brown with yellow and black pilosity; flagellum yellow-brown, basal plate with slight dorsal projection; antennal flagellum with three free flagellomeres distal to basal flagellomere complex. Proboscis partially sclerotized; theca unsclerotized; labellum with brown sclerotized plates.

Thorax. Scutum with brownish and white pruinescence, with white pilosity, except for two longitudinal stripes and lateral margins (including notopleural lobes) whitish with predominantly black pilosity and sparse yellowish pilosity, median dark scutal stripe narrower than dorsocentral white stripes. Scutellum with whitish pruinescence and white pilosity, less dense around margins. Pleuron with whitish pruinescence, pilosity mostly yellowish-white, except anepisternum and katepisternum with tuft of black pilosity. Legs slender, coxae with pruinescence and pilosity concolorous with pleuron. Trochanters, femora, tibiae and tarsi brown with black pilosity, white pilosity proximally on femura. Wing hyaline, except costal, subcostal, and marginal, cells slightly infuscated in a few specimens; veins dark brown; basicosta without macrosetae; pterostigma brown; appendix at fork of R4 +5 absent.

Abdomen: Segments (tergites and sternites) brown with slightly whitish pruinescence, covered with black pilosity and sparse yellowish pilosity; seemingly with pattern of bands and row of triangles identical to female ( Fig. 3 H); tergites 2–3 with parallel-sided median white stripe, tergites 4–7 with median white triangle.

Terminalia: Epandrium, cercus and hypoproct as figure 3D–E. Epandrium slender, divided into two parts, broad posteriorly (touching cercus) and further narrowed from second third to anterior region (entirely disjointed); anterior region glabrous, with sparse pilosity in middle to posterior regions. Cercus elongated (subequal to epandrium) with apex rounded, covered with pilosity. Hypoproct (dorsal view) shorter than cercus, entirely covered by cerci; rounded and almost entirely translucent (ventral view). Hypandrium, gonocoxite, gonostylus and aedeagus as figure 3F–G. Hypandrium + gonocoxite very robust, little longer than wide, anterior margin truncated. Aedeagus long, pointed, little shorter than gonocoxal apodeme. Gonostylus enlarged at base, further narrowed then parallelsided distally, with deep central v-shaped depression at apex.

Examined material: MEXICO, Chiapas: Revolutión, 9mi SE Buena Vista, 16°50’N; 92°00’W ME 23.iii.1953, col. R. C. Bechtel & E. I. Schlinger Stenotabanus muscoideus (Hine, 1907) det L.L. Pechuman, 1958; Letter G. B. Fairchild L. L. Pechuman 3.ii.1958, 4.iii.1958, 14.i.1959 (1ď); Jalisco: Est. Biologia Chamela 19°30'N 105°20'W 100m, 24.vii.1990, Col. Chemsak, (1Ψ); GUATEMALA, Petén Santa Elena, near Reserva Priv. Ixpanpajul, 16°54’N; 89°50’W 250m, 9.vi.2007, Col. Monzón & Camposeco (1Ψ).

Comments: The male is very similar to the female (fig. 3H), mainly by the color of the thorax and wing (fig. 3K). The abdomen differs primarily in shape as the female has a strongly narrowed apex (like an ovipositor, fig. 3H). The male terminalia differs from M. amazonicus and M. barrettoi only in the shape of the apex of the gonostylus. The male from Chiapas, Mexico, represents a new country record for Myiotabanus and a northward expansion of the known range of Myiotabanus muscoideus , previously known only from Guatemala and Costa Rica.

Figures

FIGURE 3. Myiotabanus muscoideus (A – G ɗ; H – K Ψ): A, H, body (dorsal view); B, J, head (anterior view); C, antenna (lateral view); D, E, epandrium, cercus and hypoproct (ventral and dorsal views respectively); F, G, hypandrium, gonocoxite, gonostylus and aedeagus (ventral and dorsal views respectively); I, head (lateral view); K, wing (dorsal view).