Oxysarcodexia varia (Walker, 1836)

(Figs 267–270)

Sarcophaga varia Walker, 1836: 353; Uruguay, Gorriti Island, off Maldonado. Lectotype male (by present designation) in NHMUK (not examined). [Aldrich (1930: 14) examined Walker’s type material and noted that: “The specimen mentioned as being from Port Famine is not now in the British Museum, the only one found being from Gorrite Island”; we are here designating the male from Gorriti Island as lectotype in the interests of nomenclatural stability, based on Aldrich’s (1930) illustrations.]

Sarcophaga milleri Johnston & Tiegs, 1922: 185; New Zealand. One male and one female syntypes in AM (not examined).

Sarcophaga chilensis Macquart, 1843: 261; Chile. Syntypes in MNHN (not examined). [Described from one or more male(s) and female(s) stated to be in the “Muséum”, i.e., MNHN; Aldrich (1930: 22) recovered one male and one female in MNHN.]

Sarcophaga flavicostata Macquart, 1843: 261; Chile, Concepción. Syntype (s), female in MNHN (not examined). [Described from one or more females stated to be in the “Muséum”, i.e., MNHN; Aldrich (1930: 22) recovered one female in MNHN.]

Sarcophaga truncata Schiner, 1868: 314; Chile. One male and two female syntypes in NMW (not examined). [“Ein Männchen und zwei Weibchen aus Chile ” (Schiner 1868: 314), which matches Aldrich (1930: 26), who examined “one male, two females”; no lectotype has been designated.]

Sarcophaga nobilis Thomson, 1869: 536; Argentina, Buenos Aires; Brazil; Uruguay, Montevideo. Syntypes (male and female), two female syntypes in NRM (not examined), others not located. [Thomson (1869) described the species from an unspecified number of female syntypes and one or more male syntypes; Aldrich (1930: 28) mentions “two females, Montevideo and Buenos Aires; the male mentioned by Thomson not now in the collection”.]

Diagnosis. Male. Length 6.0–10.0 mm. Postocular plate with golden pollinosity. Ocellar bristles well developed. Thorax and abdomen with pale golden pollinosity, more evident laterally, T5 partly with golden pollinosity. Three well-differentiated post-sutural dorsocentral bristles posteriorly, although a small bristle can be present among these. Apical scutellar bristles absent. Legs blackish. T3 with 1 pair of lateral marginal bristles, T4 without median marginal and with 2 pairs of lateral marginal bristles. ST5 with deep median V-shaped cleft, with setosity pilosity and bristles along margins of arms. Cercus sinuous in lateral view, apex expanded and with concave margin. Cercus with bristles ventrally over full length. Cerci black, with distal third narrower than middle part in posterior view; diverging and with a distinct constriction mid length. Pregonite with expanded base and sudden narrowing at apex; unicolorous. Postgonite with expanded base, gradually narrowing to apex; unicolorous. Distiphallus with smooth ventroapical margin, conical apex, sinuous dorsal outline and large dorsoapical swelling. Vesica asymmetrical, with rounded median projection of main branch; distal lobes well developed, rounded, sclerotized, with spines only along margins.

Remarks. See under O. augusta, O. aurata and O. marina. Both sexes of O. varia were redescribed by Lopes & Albuquerque (1955); females are characterized by having T7 interrupted medially, T8 composed of two plates lacking bristles, ST6+7 small, with marginal bristles and connected to ST8, which is well developed, with golden pollinosity, and with a deep longitudinal furrow on posterior margin. According to the groups of females proposed by Tibana & Mello (1985), we consider O. varia as belonging to the group with T7 divided into two plates. The mitochondrial genome of this species has been completely sequenced (Carmo et al. 2019).

Distribution. NEOTROPICAL. Argentina (Buenos Aires, Chubut *, Mendoza, Neuquén, Tucumán), Bolivia, Brazil (Minas Gerais *, Paraná, Rio de Janeiro, Rio Grande do Sul), Chile (Bío Bío, Concepción, Coquimbo, Juan Fernandez Islands La Araucanía, Nuble, Patagonia, Santiago, Valdivia), Uruguay (Canelones). AUSTRALASIAN/ OCEANIAN. Australia (New South Wales, Tasmania, Victoria), Fiji, French Polynesia (Society Islands), New Zealand (North Island, South Island), Norfolk Island.

Biology. This species has been reared on dung (Mendes & Linhares 2002), dead insects (Blanchard 1939) and dead lobsters (Blanchard 1939, 1942; Mulieri et al. 2010). It is attracted preferentially to feces, especially dog feces (Mariluis et al. 2007; Mulieri et al. 2010, 2011, 2015), but has also been collected on rotten minced kangaroo meat, sheep’s liver (Meiklejohn et al. 2012), rotten bovine liver (Henning et al. 2005, Mulieri et al. 2011, 2015), pig carcasses (Armani et al. 2017; Remedios-De León et al. 2017, 2019) and in organic rice fields (Acosta et al. 2017). Oxysarcodexia varia is more abundant during the spring and summer in Argentina and southern Brazil and during the summer in New Zealand and Uruguay; it was recorded in higher abundances in rural areas and grasslands as opposed to woodlands (Ferreira 1979; Henning et al. 2005; Mariluis et al. 2007; Mulieri et al. 2008, 2010; Remedios-De León et al. 2017, 2019). The species seems to prefer open pastures (Henning et al. 2005) and is known to visit flowers of Eryngium horridum (Spreng.) Less. and Coriandrum sativum (both Apiaceae), Baccharis juncea (Cass.) Desf. and Helianthus annuus L. (both Asteraceae), Sebastiania brasiliensis Spreng. (Euphorbiaceae), and Colletia paradoxa (Spreng.) Escal., Discaria americana Gillies & Hook and Scutia buxifolia (all Rhamnaceae) (Mulieri et al. 2010; Lenardis et al. 2017), and Brassica napus L. and B. rapa L. (both Brassicaceae) (Howlett et al. 2018; Stavert et al. 2018). Its potential value as a pollinator of a range of flowering crops due to its high abundance in autumn at farms in New Zealand (Canterbury region, South Island) was reported by Howlett et al. (2016). It has been recorded as a prey, in the pupal stage, of Aleochara notula Erichson, 1839, A. verberans and A. puberula Klug, 1832 (Coleoptera: Staphylinidae) (Walsh & Posse 2003). It was collected in urban, suburban and rural areas by Mulieri et al. (2011). Oxysarcodexia varia is also a species of veterinary importance, being considered a possible mechanical vector of the rabbit hemorrhagic disease virus (Henning et al. 2005).

Material examined. [♂] ARGENTINA, Chubut 47: Tecka, Corcovado, 750m 17.ii.1979, Mision Cientifica Danesa / NRM-DIPT 0014413 [NRM] // [♂] BRAZIL: Minas Gerais, Extrema, Serra do Lopo, Pedra das Flores, 27.II.2012; A. G. Savino, M. P. Nassu, M. D. Grella / Oxysarcodexia B, Extrema-MG; 27/02/2012 [LIE] // [♂] Parque Botanico HUALPEN CONCEPCIÓN CHILE / T. CEKALOVIC K. 15-18.I.70 / Hybopygia varia (Walker) Det. H. S. Lopes [MNRJ] // [♂] Cruz Alta Brasil Rio Grande do Sul S. J. Oliveira / Hybopygia varia (Walker) Det. H. S. Lopes [MNRJ].