Acanthocera marginalis Walker, 1854

Oliveira, Lia Pereira, Henriques, Augusto Loureiro & Krolow, Tiago Kütter, 2023, New records, descriptions, and redescriptions of male horse flies (Diptera: Tabanidae) in Brazil, EntomoBrasilis (e 1033) 16, pp. 1-7 : 2

Acanthocera marginalis Walker, 1854

( Figure 2 )

Male previously described by HENRIQUES & RAFAEL (1995).

Redescription (♂)

Head ( Figure 2 A-C): Eyes contiguous, glabrous, larger ommatidia on upper 2/3 and smaller ommatidia on lower 1/3. Subcallus with whitish pruinosity. Gena, parafacial and clypeus with glossy black integument, clypeus with areas of grayish pruinosity. Palpus porrect, orange-brown, with sparse white and black setulae. Antenna with orange scape, pedicel with black setulae. Postpedicel orangish at base and black at distally, dorsal tooth straight, not curved. Proboscis short, less than head height, dark brown.

Thorax ( Figures 2 A-B): Dark brown with two subtle median longitudinal bands of yellow pruinosity and yellow setulae. Notopleuron, anepisternum, katepisternum and scutellum with yellowish pruinosity and numerous yellow setulae. Legs with dark brown femora, fore and hind tibiae with a brownish on the basal half and whitish on the distal half. Mid tibia white with white setulae. Tarsus orange-brown. Wing hyaline with dark brown anterior margin, covering the costal and subcostal cells and part of the radial cell and the anterior cubital cell.

Abdomen ( Figures 2 A-B): Abdomen dark brown with sparse black setulae. Grayish pruinosity in tergites 1 and 2. Tergites 1 to 3 and sternites 2 and 3 with a whitish integument band. Sternite 1 with numerous white setulae, other sternites with black setulae.

Terminalia ( Figures 2 D-G): Epandrium with anterior region glabrous, posterior region with sparse black setulae both on dorsal and ventral surface. Cercus length longer than half of the epandrium, long setulae on the dorsal and ventral surface; posterior region almost as wide as epandrium, anterior region with apex slightly pointed. Hypoproct covered by cerci. Hypandrium + gonocoxite robust, longer than wide. Gonocoxite with a small projection at the apex. Aedeagus and gonocoxal apodemes equally long.

Material examined: BRAZIL • 3 males; Tocantins, Aurora, Estrada Cachoeira do Registro ; 12°30′20.32′′S, 46°18′10.94′′W; 14.vi.2018; Coleta Manual; Krolow, T.K. & Equipe leg.

Distribution: Bolivia, Brazil (Acre, Amapá, Amazonas, Mato Grosso, Pará, Roraima), Colombia, Ecuador (Napo, Morona Santiago), French Guiana, Guyana, Peru (Loreto), Surinam, Trinidad ( HENRIQUES & GORAYEB 1993; HENRIQUES & RAFAEL 1995; COSCARÓN & PAPAVERO 2009).

Comments: The genus Acanthocera was reviewed by HENRIQUES & RAFAEL (1995), and of the 28 described species, 15 had completely unknown males. This species represents a new record of Tabanidae for Tocantins. One of the gonocoxal apodemes was partially destroyed and the specimen’s aedeagus was lost during dissection.

Figures

Figure 2. Male of Acanthocera marginalis Walker, 1854. A. Habitus, dorsal view;B. Habitus, lateral view;C. Head, anterior view; D-E. Epandrium, cercus and hypoproct (dorsal and ventral views, respectively); F-G. Hypandrium, gonocoxite, gonostylus and aedeagus (dorsal and ventral views respectively). Source: authors.