Zelia obscura ( Walker, 1853 ) Santis & O’Hara & Couri, 2024

Santis, Marcelo Domingos De, O’Hara, James E. & Couri, Márcia Souto, 2024, Partial revision of the exclusively Neotropical species of Zelia Robineau-Desvoidy, 1830 (Tachinidae: Dexiinae: Dexiini), with the description of a new species, Zootaxa 5419 (1), pp. 1-52 : 12-16

Zelia obscura ( Walker, 1853) , comb. nov.

( Figs. 3–5 )

Dexia obscura Walker, 1853:307 . Type locality: “ Brazil ”.

Stomatodexia obscura ( Walker, 1853) . References: Austen (1907: 343, description of diagnostic characters, possibly “congeneric” with Rhamphinina picta , currently in Zelia ); Guimarães, 1971: 119 (in Stomatodexia , but as unrecognized); O’Hara et al. (2020: 698, World checklist of Tachinidae ).

Remarks. Walker (1853: 307) described Dexia obscura from an unknown number of specimens of unspecified sex from Brazil. In the interests of nomenclatural stability, the single specimen under this name in NHMUK, a male, is hereby designated as lectotype of Dexia obscura Walker, 1853 .

Type material examined. Lectotype ♂: “Holo-/type”; “ Dexia /obscura/Type/Walk.” [ Dexia obscura Walk. Handwritten ]; “obscura ” [handwritten]; “Brazil” [handwritten]; “68 4”; Brazil./ Ex coll./ Saunders./ 68.4” [handwritten]; “ Holotype ♂ / of Dexia / obscura Wlk / examined 1970/ R.W. Crosskey. ” [‘ ♂ Dexia obscura Wlk’ handwritten]; “ NHMUK 013933629 ”.

Additional material examined. BRAZIL. Rondônia: Porto Velho, Área Caiçara , S09º26’46,8” W64º49’31,1”, 1 female, 29.iii-05.iv.2012, Silva, R.R. & Albuquerque, E.Z. cols ( MZSP) ; Mato Grosso do Sul: Bodoquema , S20º41’53,5” W56º52’55,7”, 1 male, 6-21.i.2012, Lamas, Nihei & eq. cols SISBIOTA CNPQ/FAPESP ( MZSP) ; Goiás: Anápolis , 1 male, 20.xii.1935 [collector unknown] ( MZSP) ; Goiânia, Campinas , 1 male, 2.i.1936, Borgmeier & S. Lopes cols. ( MZSP) .

Diagnosis. Eye bare. Facial carina well developed. Head entirely silvery pruinose. Postpedicel entirely orange. Palpus entirely tawny yellow, cylindrical on both sexes. Katepisternum with 2+1 setae. Wing hyaline in males, smoky in females. Legs brownish black, but femur about anterior 1/3, and tibia on posteroventral region is yellowish to tawny in male and entirely blackish in females. The color of abdomen is very similar to the male of Z. potens , but it can be differentiated by: an uninterrupted median brown longitudinal vitta (that forms a triangle) on syntergite 1+2 to tergite 4 and tergite 5 light brown. Abdominal tergite 3 with one pair of median marginal setae, and without discal setae; tergite 4 with one pair of median marginal setae and two pairs of discal setae in males and none in females.

Redescription. Male. Body length: 11.5 mm.

Coloration ( Fig. 3 ). Frontal vitta and ocellar triangle dark brown to black. Fronto-orbital plate and parafacial with pale golden pruinosity, but gena brownish black. Occiput silvery pruinose with long and silver to golden setulae. Postpedicel orange. Palpus light yellow to orange. Thorax brown to dark brown with pale golden to grayish pruinosity; prescutum with four dark vittae, in the two inner vittae are thinner than the outer, postscutum with five vitta the median one stars after the suture and goes until the hind margin; the inner vittae is half the length of the outer, neither reaching the scutellum. Scutellum pale golden to grayish pruinosity. Wing hyaline, slightly light brown along the veins. Calypter hyaline. Halter yellow-tawny. Posterior spiracle brownish black. Legs brownish black, but femur about anterior 1/3, and tibia on posteroventral region is yellowish to tawny; tarsi darker. Claws brown, pulvilli yellow. Abdomen dark yellow, with uninterrupted median brown longitudinal vitta (that forms a triangle) on syntergite 1+2 to tergite 4; posterior margin of tergites 1+2 to 4 brownish black, increasing in extension along the tergites; tergite 5 light brown; silver pruinosity on 1/4 of anterior margin in tergite 4 and in tergite 5, except for mid small area black vitta, entirely silver pruinose.

Head ( Fig. 3A–C ). Vertex about 0.2x head width in dorsal view. Frontal vitta, at the narrowest point, equal to the width of ocellar triangle. Inner vertical setae and outer vertical seta absent. Fronto-orbital plate with 12–13 pairs of proclinate setae; narrower than frontal vitta and parafacial. Width of parafacial measured between inner margin of compound eye and antennal insertion is 0.5x the width of gena. Postpedicel slender, 2.5x the combined length of scape and pedicel; longer than the dorsal, longest cilia ca. 7x basal width of arista. Facial carina developed. Facial ridge with two to three setulae on lower third. Lower facial margin protruding, visible in profile. Eye about 0.83x the head height. Gena about 0.32x eye height. Vibrissa long, inserted above lower facial margin. Prementum about 2x the length of palpus. Labella narrow, about 0.3x the prementum.

Thorax ( Figs. 3A, C ). Acrostichals 2+2-1. Dorsocentral 3+3. Intra-alar 1+1; intra-postalar absent. Supra-alar 2+4-3, first postsutural weak. Postpronotal lobe with four setae, three forming an anterior row and one posterior. Anepisternum with five strong setae and with one upward directed setulae anteriorly. Scutellum with one basal, one lateral, one apical and one discal pairs of setae. Katepisternum with 2+1 setae. Anepimeron with one long setae. Postalar callus with 2 setae. Legs. Fore coxa with many setae anteriorly; fore femur with dorsal and posteroventral rows of setae; fore tibia with 1 anteordorsal setae on apical third and 1 on median third, 1 posteroventral setae on median third, 3 preapicals, 2 posterodorsal and 1 posteroventral. Mid femur with 3 anterior setae on median third, 2 posteroventral on apical third; mid tibia with 1 ventral seta on apical third, 2 posterodorsal setae on median third, 6 preapicals, 1 anterior, 1 anterodorsals 3 posteroventral and 1 ventral. Hind femur with three anteroventral setae on basal half and three ventral setae on basal half and with row of anterodorsal setae; hind tibia with a row of posterodorsal and 1 posteroventral on median third, 3 posteroventral and 3 anteroventral seta on distal third, 3 preapicals, anterodorsal, 1 anteroventral, 1 ventral.

Abdomen ( Figs. 3A, C ). Syntergite 1+2 with a pair of lateral marginal setae. Tergite 3 with one pair of median marginal seta and one pair of lateral marginal pairs of seta. Tergite 4 with two discal setae and a marginal row of setae. Tergite 5 with one pair of discal setae and two rows of marginal setae. Tergite 5 slightly pointed apically. Terminalia ( Fig. 4 ). Tergite 6 about 1/4 length of syntergosternite 7+8. Sternite 5 with basal plate long and outwardly curved ( Fig. 4C ). Epandrium broad in posterior view, setulose, and closed dorsally ( Fig. 4A–B ). Anterior epandrial process poorly developed. Cerci not fused, broad, and distally slightly tapered in posterior view. Surstylus broad, not fused with epandrium, convex, and setulose in posterior view; distally tapered in lateral view ( Fig. 4A–B ). Apodeme ejaculatory broad apically and narrowing posteriorly, with its base enlarged. Pregonite with setulae anteriorly, connected basally to hypandrium by a sclerotized seam. Basiphallus about twice the length of postgonite. Extension of dorsal sclerite of distiphallus long, more than half of the length of dorsal sclerite; dorsal sclerite ventrally serrulated; granular zone about 0.7x the length of dorsal sclerite ( Fig. 4D ).

Female ( Fig. 5 ). Differs from male as follows: Vertex about 0.23x head width in dorsal view. Fronto-orbital plate with 2 proclinate orbitals and 1 reclinate setae. Palpus subclavate. Wing smoky. Abdomen brownish black in ground color, with silver pruinosity anteriorly; tergite 5 brownish on posterior margin. Abdominal tergite 4 with a median marginal pair of setae and tergite 5 with one pair of discal setae. Claw and pulvilli short, shorter than tarsomere 5. Abdomen more ovate.

Biology. Unknown.

Distribution. Brazil (Rondônia, Mato Grosso do Sul and Goiás states, new records).

Remarks. Austen’s notes about Walker’s types at the NHMUK (1907: 24), regarded Dexia obscura as “… probably congeneric with Rhamphinina picta, Bigot ...”, currently a member of the genus Zelia . Later, Austen also noted that Brauer (1897) considered Zelia picta , along with Zelia potens , as belonging to “… Stomatodexia according to the head, and to Leptoda according to the bend of the fourth vein”. Guimarães (1971) considered D. obscura as belonging to Stomatodexia and this placement was followed by O’Hara et al. (2020). However, as shown herein, this species belongs conclusively to the genus Zelia accordingly to the detailed comparative morphology of the adults and the male terminalia.

Figures

FIGURE 3. Zelia obscura (Walker, 1853), holotype male (NHMUK). A. Dorsal habitus. B. Head, frontal view. C. Lateral habitus. D. Labels.

FIGURE 4. Zelia obscura (Walker, 1853), male from Goiás, Brazil (MZSP). A. Epandrium, cercus and surstylus, lateral view. B. Epandrium, cerci and surstyli, posterior view. C. Sternite 5, posterior view. D. Hypandrium, phallapodeme, basiphallus, epiphallus, distiphallus, pregonite and postgonite, lateral view. Abbreviations: basph = basiphallus; cerc = cercus; distph = distiphallus; ej apod = ejaculatory apodeme; epand = epandrium; epiph = epiphallus; hypd = hypandrium; pgt = postgonite; phapod = phallapodeme; pregt = pregonite; sur = surstylus.

FIGURE 5. Zelia obscura (Walker, 1853), female from Rondônia, Brazil (MZSP). A. Dorsal habitus. B. Head, frontal view. C. Lateral habitus.