Pachyrrhiza argentatoides, 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 : 281-283

Pachyrrhiza argentatoides sp. n.

( Figs 9–12 , 30C, I , 31B , 33B , 35 )

Zoobank: urn:lsid:zoobank.org:act:9064D8D3-CBF7-462C-B6F7-A652AA5AF332

Diagnosis. Parafacial with small patch of black setae adjacent to gena (absent in female); hind femur with one or two subapical anteroventral macrosetae; prosternum without setae medially; scutum with bases of setae dark; wing hyaline, yellow infuscate anteriorly; male abdomen with silver velutum pubescence; mid and hind coxal pile absent on posterior surface; femora yellow, sometimes with black suffusion dorsally in male.

Description. Body length: 6.0– 8.4 mm. Head with frontal pubescence greyish brown (male) or dark yellow (female) dorsally, silver around antennal base; male frons without setae, female with sparse, short, dark setae; small dark patch of parafacial setae adjacent to gena (absent in female); genal setae pale; occiput grey or light brown with brown pubescence; antennal scape length slightly longer than maximum width, dark yellow, densely covered with large, dark setae in male (shorter and sparser in female); flagellum dark yellow with brown pubescence. Thorax with scutum and scutellum mottled pubescence grey (male) or tan-brown (female), numerous erect, elongate black setae (denser and longer in male), setal bases dark brown; pleuron with dense, silver-grey pubescence; prosternum without setae; katatergite setae uniform pale; mid and hind coxa lacking setae on posterior surface; femora uniform yellow, suffused with brown-black dorsally (male); femora with short dark setae admixed with elongate pale setae ventrally; hind femur with 1 or 2 subapical anteroventral macrosetae; tibiae dark yellow; tarsi dark yellow; wing hyaline, tinted yellowish infuscate anteriorly, costal cell yellow infuscate; scutal chaetotaxy: notopleural, 4–5; supra alar, 1; post alar, 1; dorsocentral, 4–5; scutellar, 2. Abdomen base colour dark brown dorsally, yellow margins broader laterally; male with silver velutum on tergites 2-7, admixed with extensive long, pale setae, female with sparse short black setae; male terminalia dark yellow. Male and female genitalia as per genus description except: epandrium with dark medial stripe and distiphallus broad distally.

Etymology. The specific epithet is modified after P. argentata with the Greek suffix - oides, resembling; referring to the similarity of the two species.

Comments. Pachyrrhiza argentatoides sp. n. appears closely related to P. argentata and is differentiated from all other Pachyrrhiza species by the lack of parafacial setae patch in the female, hyaline wings and the male abdomen with silver velutum covering. This species is found in central Chile and western Argentina.

Type material. Holotype male, CHILE: Arauco Province: Parque Nacional Nahuelbuta Pichinahuel (-37.24, -73.32), 15.I.1959, L.E. Peña (MEI079750; MEUC). Paratypes. CHILE: Arauco Province: 1 male, same data as holotype ( MEI 079758; CSCA); 1 female, Parque Nacional Nahuelbuta, 1300 m (-37.76, -72.98), 24.I.1967, M.E. Irwin ( MEI 154209; CSCA). Chubut Province: 1 male, 1 female, Cholila, Chacra of Stephen Bussey, Malaise in steep gorge [-42.4503, -71.45], 23–31.XII.2005, M.E. Irwin, 560 m ( CSCA). Malleco Province: 6 females, Parque Nacionale Nahuelbuta [-37.8085, -73.016], 1150 m, Malaise in Araucaria - Nothofagus forest, 9–12.I.2000, D.W. Webb, D.K. Yeates, M.E. Irwin, E.I. Schlinger ( MEI 121530–5; CSCA). Ñuble Province: 1 female, same data as holotype ( MEI 117067; MEUC); 1 male, 3 km E. Las Trancas (-36.915, -71.453), 4.I.2000, M.E. Irwin, hand netted ( MEI 121268; CSCA). ARGENTINA: Rio Negro Province: 12 males, 2 females, Nahuel Huapi National Park, 2 km S. Rincon Chico, Malaise in Patagonian steppe [-41.0025, -71.1268], 24–31.XII.2005, M.E. Irwin, 890 m ( CSCA, MACN).

Figures

FIGURE 9. Pachyrrhiza argentatoides sp. n., adult male, oblique view.

FIGURE 10. Pachyrrhiza argentatoides sp. n., adult male, lateral view.

FIGURE 11. Pachyrrhiza argentatoides sp. n., adult female, oblique view.

FIGURE 12. Pachyrrhiza argentatoides 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 33. Pachyrrhiza spp. male genitalia, gonocoxites with aedeagus in situ, ventral view (left) and epandrium (right). A. P. argentata Oldroyd, 1968; B. P. argentatoides sp. n.; C. P. elegantissima sp. n. Scale line: 0.2 mm.

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