Stibasoma bifenestratum Philip Philip

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 : 11-13

Stibasoma bifenestratum Philip Philip reval.

( Figs. 19–24 )

Stibasoma bifenestrata Philip, 1966: 526 (description); Fairchild, 1971: 75 (catalog, junior synonym of S. chionostigma ); Fairchild & Burger, 1994: 112 (as synonym of S. chionostigma ).

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

Redescription. Female (holotype). Head. Frons dark brown to black, with silver pollinosity best seen in dorsal view, with black hairs. Frontal callus slightly narrower than frons, dark brown to black; mid-callus long, almost reaching the vertex. Subcallus dark brown to black, with silver pollinosity, best seen in dorsal view; base of the antenna with yellow pollinosity. Antenna dark brown to black, scape and pedicel with dark brown to black hairs; flagellum with golden pollinosity; basal flagellomere with dorsal spine reaching the second flagellomere. Face and parafacia dark brown to black with silver pollinosity, best seen in dorsal view. Gena and postgena dark brown to black, with silver pollinosity and white hairs. Palpus dark brown, with silver pollinosity and white hairs.

Thorax. Scutum and scutellum dark brown, with gray pollinosity and black hairs; Postpronotal lobe lighter than the scutum, with white hairs proximally and black hairs distally; notopleuron dark brown, with silver gray pollinosity and black hairs; proepisternum and proepimeron dark brown to black, with silver pollinosity and white hairs; anepisternum dark brown to black, with gray pollinosity and black hairs; few white hairs on base of wing; anepimeron dark brown, with black hairs; katatergite dark brown to black with gray pollinosity and white hairs; katepisternum dark brown to black with gray pollinosity and black hairs; katepimeron dark brown with dense silver gray pollinosity. Coxa 1 dark brown to black, with white hairs proximally and black hairs distally; coxae 2 and 3 dark brown to black with gray pollinosity and black hairs; femur dark brown to black with black hairs; tibia 1 inflated, dark brown to black, with white hairs proximally on the anteroventral, anterior, anterodorsal, dorsal and posterodorsal sides, with black hairs on the remaining parts; tibia 2 dark brown to black with white hairs proximally on anterior and anterodorsal sides and black hairs on remaining parts; tibia 3 dark brown to black with black hairs; tarsus dark brown to black with black hairs, except for reddish hairs on ventral side. Wing brown with two conspicuous lighter areas: one hyaline in the apex, along distal part of cells r2+3 and r4 and the second yellow, in middle, along cells c, sc, r1, r2+3, r5 and d; pterostigma yellow; venation brown. Halter brown with yellowish apex.

Abdomen. Tergites entirely dark brown to black with black hairs and a row of white hairs on last visible tergite; sternite 1 dark brown to black with black hairs, except for yellow hairs on the lateral part of the distal margin; the other sternites dark brown to black with black hairs proximally with row of yellow hairs distally.

Measurements. (n = 1, holotype female) Body length: 14.43mm. Wing length: 13.57mm. Frontal index: 4.84. Divergence index: 0.93.

Description. Male (Puerto Viejo, 23.vii.1992). Head. Dorsal part of the eye dark brown, with large ommatidia; ventral part of the eye black, with small ommatidia. Subcallus dark brown, with silver pollinosity. Scape and pedicel dark brown to black, with gray pollinosity and black hairs; flagellum dark brown with golden pollinosity; basal flagellomere with dorsal spine reaching first flagellomere. Face and parafacia dark brown, with silver pollinosity and white hairs. Gena and postgena dark brown with silver pollinosity and white hairs. Palpus dark brown to black, with gray pollinosity and mixed black and white hairs.

Thorax. Scutum and scutellum dark brown, with gray pollinosity and black hairs. Postpronotal lobe lighter than the scutum, with white hairs. Notopleuron lighter than the scutum, with gray pollinosity and black hairs. Proepisternum and proepimeron dark brown, with gray pollinosity and white hairs. Anepisternum dark brown with gray pollinosity and white hairs proximally and black hairs distally. Anepimeron dark brown with gray pollinosity and mixed black and white hairs. Katatergite dark brown with gray pollinosity and white hairs. Katepisternum dark brown with gray pollinosity and white hairs. Katepimeron brown with silver gray pollinosity. Coxa dark brown to black with gray pollinosity and mixed black and white hairs. Femur dark brown to black with black hairs. Tibia dark brown to black with black hairs, except for white hairs proximally on the anterior, anterodorsal and dorsal sides. Tarsus dark brown to black with black hairs, except for reddish hairs on the ventral side. Wing brown, with 3 conspicuous lighter areas: the first yellow, along proximal part of the cells c, br, bm, cup and a1; the second also yellow, along distal part of the cells c and sc, the middle part of r1, the proximal part of r2+3 and of r5 and the distal part of the cell d; and the third hyaline, ranging only the apex of the wing. Venation brown, except on the lighter areas, where the venation is also yellow. Pterostigma yellow. Halter yellow with apex whitish.

Abdomen. Tergites 1 and 2 entirely yellow with yellow hairs. Other tergites dark brown with black hairs mixed with few white hairs. Sternites I and II yellow with yellow hairs. Other sternites yellow to light brown with black hairs proximally and distal margin lighter with yellow hairs.

Measurements. (n = 1, male, Puerto Viejo, 23.vii.1992) Body length: 14.57mm. Wing length: 11.14mm.

Type-locality. Nicaragua.

Distribution. Costa Rica; Nicaragua.

Type material examined. “Recreo, Dept.\ Zelaya, Nic[arágua].\ July, 1953\ K. Neiland” “ HOLOTYPE \ Stibasoma \ bifenestrata \ C.B.Philip 66” “CORNELIUS B. PHILIP\ COLLECTION\ Donated to California\ Academy of Sciences” “California Academy\ of Sciences\ Type No. 12892” (holotype, female, CAS).

Additional material examined. COSTA RICA. Heredia: female, Puerto Viejo, 6.vii.1965, M.G. Naumann, ( UNH); male, Puerto Viejo, Estação Biológica La Selva - 10º26’N 84º01’W, 23.vii.1992, H.A. Hespenheide, ( UNH); female, idem, 24.vii.1992, H.A. Hespenheide, ( UNH).

Remark. S. bifenestratum and S. chionostigma are morphologically similar (compare figure 20 with figure 26), with the main difference in the pollinosity of the subcallus. They are also sympatric species which supports the hypothesis that S. bifenestratum and S. chionostigma are distinct. The termination of bifenestrata was changed to bifenestratum to agree with the neuter gender of the genus.

Figures

FIGURES 19 – 24. Figures 19 – 21, Stibasoma bifenestratum holotype Ƥ: (19) dorsal view; (20) frontal view; (21) lateral view; figures 22 – 24. S. bifenestratum 3: (22) dorsal view; (23) frontal view; (24) lateral view.