Pachyrrhiza parargentata, Irwin & Winterton, 2021

Irwin, Michael E. & Winterton, Shaun L., 2021, Revision of the Patagonian stiletto fly genus Pachyrrhiza Philippi (Therevidae Agapophytinae), Zootaxa 4975 (2), pp. 273-305 : 287-290

Pachyrrhiza parargentata sp. n.

( Figs 18–21 , 30H , 31C , 34A , 35 )

Zoobank: urn:lsid:zoobank.org:act:17532EE9-885A-4D60-958B-F2B315EC94F9

Diagnosis. Parafacial with patch of black setae adjacent to gena; hind femur with one or two subapical anteroventral macrosetae; prosternum without setae medially; wing mostly hyaline, slightly mottled infuscate anteriorly; male abdomen with silver velutum pubescence; mid and hind coxae with white setae on posterior surfaces.

Description. Body length: 6.5–7.5 mm. Head with frons light brown pubescent, female with dark brown band above antenna, frontal vestiture with patch of short setae above antenna, shorter than setae on scape, female with short to moderate length setae over entire frons; parafacial setae as small dark patch adjacent to gena; genal setae white; occiput brown with grey pubescence, denser laterally; antennal scape slightly longer than maximum width, brown with grey pubescence, densely covered with large, dark setae (fewer in female); flagellum brown with grey pubescence. Thorax with scutum and scutellum with grey-tan pubescence and scattered, dark brown markings, numerous erect elongate black setae, denser and longer anteriorly, especially in male, setal bases dark brown; scutal markings as narrow brown medial stripe, lateral stripes broken; pleuron with dense silver-grey pubescence; prosternum without setae medially; katatergite setae all white; femora dark brown (male) or dark yellow, suffused with brown-black dorsally (female), short dark setae, admixed with elongate pale setae ventrally; hind femur with one or two subapical anteroventral macrosetae; tibiae yellow, dark grey-brown apically; tarsi dark yellow with apices brown; wing hyaline, mottled infuscate anteriorly, costal cell brown infuscate basally, yellow distally; scutal chaetotaxy: notopleural, 3–5; supra alar, 1; post alar, 1; dorsocentral, 4; scutellar, 2. Abdomen base colour mostly dark brown in male, female brown with glaucous grey pubescence, intersegmental membrane distinctly pale; male vestiture with extensive long, pale setae, female with scattered, short, dark setae, male abdomen with silver velutum on tergites 2–7; terminalia dark yellow. Male and female genitalia as per genus description except epandrium with dark medial stripe and distiphallus narrow distally.

Etymology. The specific epithet is modified after P. argentata with the Greek prefix para-, beside; referring to the similarity of the two species.

Comments. Pachyrrhiza parargentata sp. n. is known from relatively few specimens and appears endemic to the Las Trancas Valley. It is very similar to P. argentatoides sp. n. but is differentiated by the presence of pale setae on the posterior surfaces of the mid and hind coxae.

Type material. Holotype male, CHILE: Ñuble Province : Las Trancas [approximated as -36.908, -71.492], 1200m, Malaise, 24–27.XI.1994, L. Peña-Ugarte ( MEI117062 ; MEUC) . Paratypes. CHILE: Ñuble Province: 1 female, same data as holotype ( MEI117067 ; MEUC) ; 1 male, 3 km E. Las Trancas (-36.915, -71.453), 4.I.2000, M.E. Irwin, hand netted ( MEI121268 ; CSCA) ; 1 male, Las Trancas , 73 km SE Chilián [approximated as -36.908, -71.492], 14–15.XII.1993, G.&M. Wood ( MEI123789 ; CAS) ; 1 male, 1 female, Las Trancas [approximated as - 36.908, -71.492], 21–30.XI.1964, L.E. Peña ( MEI079709 , 079768 ; CNC) .

Figures

FIGURE 18. Pachyrrhiza parargentata sp. n., adult male, oblique view.

FIGURE 19. Pachyrrhiza parargentata sp. n., adult male, lateral view.

FIGURE 20. Pachyrrhiza parargentata sp. n., adult female, dorsolateral view.

FIGURE 21. Pachyrrhiza parargentata sp. n., adult female, lateral view.

FIGURE 30. Pachyrrhiza spp. heads, oblique view. A. P. argentata Oldroyd, 1968, male; B. P. subpictipennis sp. n., male; C. P. argentatoides sp. n., male; D. P. pictipennis Philippi, 1865, female; E. P. argentata Oldroyd, 1968, female; F. P. elegantissima sp. n., female; G. P. pictipennis Philippi, 1865, male; H. P. parargentata sp. n., male; I. P. argentatoides sp. n., female; J. P. subpictipennis sp. n., female; K. P. elegantissima sp. n., male.

FIGURE 31. Pachyrrhiza spp. wings. A. P. subpictipennis sp. n.; B. P. argentatoides sp. n.; C. P. parargentata sp. n.; D. P. elegantissima sp. n.; E. P. argentata Oldroyd, 1968; F. P. pictipennis Philippi, 1865.

FIGURE 34. Pachyrrhiza spp. male genitalia, gonocoxites with aedeagus in situ, ventral view (left) and epandrium (right). A. P. parargentata sp. n.; B. P. pictipennis Philippi, 1865; C. P. subpictipennis sp. n. Scale line: 0.2 mm.

FIGURE 35. Distribution of Pachyrrhiza species in Chile and Argentina.