Stibasoma chionostigma (Osten Sacken)

Turcatel, Mauren, Carvalho, Claudio José Barros De & Rafael, José Albertino, 2010, A taxonomic revision of Stibasoma Schiner, 1867 (Diptera: Tabanidae), Zootaxa 2368, pp. 1-39 : 13-15

Stibasoma chionostigma (Osten Sacken)

( Figs. 25–27 )

Tabanus chionostigma Osten Sacken, 1886: 54 (description).

Stibasoma chionostigma ; Kröber, 1932: 242, 252 (citation, redescription); Fairchild, 1940: 684 –685 (key, citation); Fairchild, 1953: 267 (citation, key); Philip, 1966: 526 (citation). Fairchild, 1971: 75 (catalog); Fairchild, 1986: 76, 77–78 (key, description of the male); Fairchild & Burger, 1994: 112 (catalog).

Stibasoma pachycephalum Bigot, 1892: 636 (description); Knab, 1913: 408, 411 (key, citation); Kröber, 1932: 243, 244, 251–253 (citation, key, designation as junior synonym of S. chionostigma ); Philip, 1966: 526 (citation).

Stibasoma flavistigma Hine, 1912: 516 (description); Knab, 1913: 408, 409 (key, citation); Kröber, 1932: 242, 244, 245 (citation, key, redescription); Fairchild, 1940: 684 –685 (designation as junior synonym of S. chionostigma ); Philip, 1966: 526 (citation).

Diagnosis. Predominantly dark brown; subcallus shiny; wing brown with hyaline apex and a conspicuous spot light yellow in middle.

Redescription. Female (holotype S. chionostigma ). Head. Frons dark brown to black, with few black hairs and silver pollinosity along the margin of the eyes. Frontal callus as wide as frons, dark brown, shiny; subcallus dark brown, shiny; base of the antenna with golden pollinosity. Scape and pedicel dark brown to black, with black hairs; flagellum light brown, with golden pollinosity; basal flagellomere with dorsal spine reaching the second flagellomere and a dorsal angle. Face and parafacia dark brown to black, with silver gray pollinosity best seen in dorsal view. Gena and postgena dark brown to black, with dark brown hairs and silver gray pollinosity on the margin of the eyes. Palpus dark brown to black, with black hairs.

Thorax. Scutum and scutellum dark brown to black, with few black hairs and gray pollinosity. Postpronotal lobe lighter than the scutum, with white hairs. Notopleuron dark brown to black, with gray pollinosity and black hairs. Proepisternum and proepimeron dark brown to black, with black hairs. Anepisternum dark brown to black, with black hairs and few white hairs on base of wing and silver pollinosity best seen in frontal view. Anepimeron dark brown to black, with black hairs. Katatergite dark brown to black, with black hairs. Katepisternum dark brown to black, with silver pollinosity, best seen in frontal view, and black hairs on the posterodorsal side. Katepimeron dark brown to black with silver gray pollinosity. Coxa 1 dark brown to black, with black hairs and yellowish-gray pollinosity; coxae 2 and 3 dark brown to black, with black hairs and silver gray pollinosity. The rest of the leg dark brown to black with black hairs, except for few white hairs on the proximal anterior, anterodorsal, dorsal and posterodorsal sides of the tibia and reddish hairs on the ventral side of the tarsus. Wing brown, with two conspicuous lighter areas: one yellowish in middle, along distal part of the cells c and sc, the middle of r1, the middle-proximal part of r2+3 and r5 and the distal part of d; the second hyaline, in the apex. Venation brown, except on first lighter area, where the venation is also yellow. Pterostigma yellow. Halter light brown with yellowish apex.

Abdomen. Tergites dark brown to black with black hairs, except for yellow hairs laterally on the first segment and on the distal margin of the last segment. Sternites dark brown to black with black hairs on the proximal part, distal margin with rows of yellow hairs, forming band.

Measurements. (n = 1, holotype female S. chionostigma ) Body length: 17.71mm. Wing length: 15.71mm. Frontal index: 5.26. Divergence index: 1.08.

Male: unknown.

Type-locality. Guatemala.

Distribution. Mexico to Colombia.

Type material examined. Stibasoma chionostigma : “ Tabanus \ Type \ chionostigma \ O.S.” “Atoyac\ Vera Cruz\ April. H.H.S.” “Identified by\ Williston” “B.C.A. Dipt. I.\ Tabanus \ chionostigma \ O.S.” “Central America.\ Pres. By\ F.D.Godman.\ O.Salvin.\ 1903-172.” “ T.chionostigma \ O.S.” “ HOLOTYPE \ Tabanus \ chionostigma Osten-Sacken \ det. J.E. CHAINEY 1978” “ BMNH (E)#\ 253479” (holotype, female, BMNH). Stibasoma flavistigma : “Vera Cruz\ Crawford” “7333” “ TYPE \ Stibasoma \ flavistigma \ Hine” “ Stibasoma \ flavistigma \ Hine” “ Stibasoma \ flavistigma \ Hine = S.\ chionostigma \ O.S.” “ OSUC 0216515” (Holotype, female, OSUC).

Additional material examined. BELIZE. Cayo: female, Augustine, 17.viii.1961, D. J. Lewis, ( BMNH). COSTA RICA. Heredia: female, Puerto Viejo, Estação Biológica La Selva - 10º26’N 84º01’W, 18.viii.1996, H.A. Hespenheide, ( UNH). GUATEMALA. Female, 1955, Angrand, ( MNHN).

Figures

FIGURES 25 – 27. Stibasoma chionostigma holotype Ƥ: (25) dorsal view; (26) frontal view; (27) lateral view.