Chaetotheresia insolita ( Walker, 1853 ) de Santis & de V. P. Dios, 2023

de Santis, Marcelo Domingos & de V. P. Dios, Rodrigo, 2023, Monotypic no more: revision and an additional species for the genus Chaetotheresia Townsend, 1931 (Diptera: Tachinidae), Journal of Natural History 57 (5 - 8), pp. 285-298 : 294-296

Chaetotheresia insolita ( Walker, 1853) comb. nov.

( Figure 2 )

Dexia insolita Walker, 1853: 318 . Male lectotype: Brazil ( NHMUK) .

Hystrichodexia insolita ( Walker, 1853) . Guimarães 1971: 35 (catalogue, new combination as Hystrichodexia ); O̍ Hara and Henderson 2020a: 53 (checklist of World Tachinidae ).

Note

At the NHMUK collection the male syntypes from the original description of Walker were examined by Roger Crosskey. One male presents a lectotype label attached by Crosskey in 1970. However, the lectotype designation was not published. In the interests of nomenclatural stability and to restrict the name to a single specimen, the male syntype that presents Crosskey̍s lectotype label and the additional label ′ NHMUK 013933556 ̍ is hereby designated as lectotype of Dexia insolita Walker, 1853 .

The current combination for this species is Chaetotheresia insolita (1853) comb. nov.

Type material examined

Lectotype J: ′Lecto-/type̍; ′ Dexia / Type/ insolita/ Walk̍.; ̍68–4̍; ′insolita; ′ Brazil./ Ex coll./ Saunders./ 68.4̍.; ′ Dexia / insolita Walk. / LECTOTYPE J/ designated by R. W. Crosskey 1970̍; ′ NHMUK 013933556̍( NHMUK). Specimen in good condition, but head and scutum slightly moulded; some setae on the scutellum missing; fore left tibia and tarsus missing, mid right leg missing, left mid tarsus missing, and left hind leg missing.

Diagnosis

Thorax with whitish pruinosity dorsally; abdomen light brown, syntergite 1 + 2 with 1 pair short of median marginal setae.

Redescription

Male. Body length: 12.2 mm.

Colouration ( Figure 2 ). Occiput whitish, with long yellowish hairs. Head with light silver pruinosity. Scape light brown and pedicel dark brown. Postpedicel yellow to orange. Arista dark brown. Palpus light yellow. Labellum and prementum brownish black. Scutum brownish black, but presutural region and anterodorsal portion of postsutural region with whitish pruinosity; presutural region with 5 brownish-black vittae, the 3 central ones narrow and the 2 peripheral ones broad. Wing smoky, more darkened in proximal area and along the veins. Tegula yellowish, basicosta tawny. Halter yellowish brown. Posterior spiracle tawny to yellowish brown. Legs brownish black, but anterior and posterior surfaces of fore, mid, and hind tibiae light brown. Pulvilli yellow; claws light brown with darker tip. Upper and lower calypters dark brown. Abdomen light brown; tergite 5 with golden-greyish pruinosity, viewed dorsally.

Head ( Figure 2 ). Ocellar setae long, divergent and proclinate. Inner vertical seta decussate and reclinate, outer vertical seta decussate. Width of parafacial, measured at distance between inner margin of eye and antennal insertion, 1.5× height of gena. Arista long plumose. Fronto-orbital plate with lowermost frontal seta not reaching antennal insertion. Postpedicel about 1.5× the combined lengths of scape and pedicel. Fronto-orbital plate with setulae throughout its length, parafacial bare. Frontal vitta narrowed dorsally. Lower facial margin protruding, visible in profile. Vibrissa arising above lower facial margin. Gena about 0.4× eye height. Prementum about 0.5× head height. Labellum developed, about 0.4× as long as prementum.

Thorax ( Figure 2 ). Acrostichal setae 4+? (area too damaged to be certain). Dorsocentral setae 4 + 4. Intra-alar setae 1 + 2. Intra-postalar seta absent. Supra-alar setae 2 + 4. Postpronotal lobe with 5–6 setae. Notopleuron with 2 equal-sized setae. Postalar callus with 3 setae, the outer one weak. Propleuron setulose and prosternum bare. Anepimeron with numerous long setae. Katepisternal setae 2 + 3. Scutellum at least with 3 pairs of basal, 1 pair of long and divergent subapical, and 1 pair of strong, straight apical setae; numerous erect discal setae. Postmetacoxal area membranous. Anatergite bare. Posterior spiracle with posterior lappet larger than anterior. Katepimeron setulose.

Wing. Costal spine undeveloped. Cell r 4+5 open at wing margin; length of opening shorter than crossvein r-m. Crossvein dm-cu sinuous. Vein R 4+5 with setulae ventrally and dorsally at base; with numerous erect setae.

Legs. Fore femur posteroventral rows of setae; fore tibia with 5 median anterodorsal, 2 posteroventral in apical third, 4 preapical, 2 dorsal, 1 anterodorsal and 1 posteroventral setae. Mid femur with 6 anteroventral, 2 anteromedian and 2 preapical; mid tibia with 3 median anteroventral and 1 posteroventral setae. Hind femur with posterodorsal and posteroventral rows of setae; hind tibia with rows of anterodorsal (4) and posterodorsal setae (4), 4 preapical, 2 anterodorsal, and 2 posteroventral setae. Claws and pulvilli elongate, fore claws and pulvilli longer than 5th tarsomere.

Abdomen ( Figure 2 ). Syntergite 1 + 2 with mid-dorsal longitudinal depression extending to posterior margin. Syntergite 1 + 2 with 1 pair of lateral marginal setae; tergite 3 with 7 marginal setae in most of posterior margin; tergite 4 with a row of marginal setae; tergite 5 with a row of marginal setae. Abdomen fully covered with long setulae.

Terminalia. Not examined, only lectotype male and paralectotypes were available.

Female. Unknown.

Biology. Unknown.

Distribution. Brazil.

Comments

This species shares all the diagnostic morphological characteristics of the genus, mainly considering the number and position of the erected setae on the abdomen, so we could include it in Chaetotheresia .

Figures

Figure 2. Chaetotheresia insolita (Walker, 1853), lectotype J. (A) Dorsal habitus. (B) Lateral habitus.