Seri obscuripennis (Oldenberg)

Cumming, Jeffrey M. & Cumming, Heather J., 2011, The flat-footed fly genus Seri Kessel & Kessel (Diptera: Platypezidae), Zootaxa 3136, pp. 61-68 : 66-67

Seri obscuripennis (Oldenberg)

Clythia obscuripennis Oldenberg, 1916: 123 (male and female). Platypeza obscuripennis (Oldenberg) : Chandler, 1974: 22. Seri obscuripennis (Oldenberg) : Chandler, 1974: 22.

Diagnosis. Body color grey in female without bluish hue, legs greyish brown with tarsi more yellowish brown, male black with darker legs than female; wing of female with M2 equal to apical section of M1+2 (see Chandler 1974, fig. 22); hind tarsomere 2 of female with two long anterior setae at apex (see Chandler 2001, fig. 277); male genitalia with phallus projected well beyond hypandrium (see Chandler & Shatalkin 1998, fig. 29; Chandler 2001, fig. 278).

Larva and puparium described by Chandler (2001) and Rotheray et al. (2004): larva cylindrical, slightly dorsoventrally flattened, lateral and dorsal processes of body segments inconspicuous and hair-like, anal segment with small pair of caudal wart-like protuberances; puparium with dehiscence lines of operculum along lateral margins of segments 2–4 and posteriorly along basal two thirds of tergite 5.

Distribution. Although rarely collected, this species is widespread in the Palaearctic Region having been recorded from Europe ( Britain, Norway, Sweden, Finland, Netherlands, Poland, Czech Republic, Switzerland, Austria, Hungary, Romania, Central Russia) and the Russian Far East (Amur Region) (Chandler 1991, 2001). Shatalkin (1985) indicated that S. obscuripennis was more commonly collected in the Amur Region than in Central Russia. Ševčík (2001) and Webb (2004) were also able to obtain series of adult specimens by rearing larvae from Polyporus fungi in the Czech Republic and Britain, respectively.

Remarks. Despite lack of males, Chandler (1974) considered it best to maintain S. obscuripennis and S. dymka as separate species, because closely related Palaearctic and Nearctic platypezid taxa have generally been found to be specifically distinct. Comparison of the different phallus lengths in both species now supports Chandler’s decision. Chandler (2001, fig. 277) also illustrated the female hind tarsus of S. obscuripennis with two long anterior setae at the apex of tarsomere 2, whereas females of S. dymka consistently have only one long anterior seta. This may be an additional diagnostic feature that distinguishes females of the two species.

Vaňhara (1986) recorded a single adult of S. obscuripennis from a light trap set in a hardwood forest in the Czech Republic. Ševčík (2001) and Webb (2004) reared larvae S. obscuripennis from tough textured Polyporus fungi species, namely P. durus (= P. badius ) and P. v a r i u s. The host association with the softer textured Polyporus squamosus fungus suggested by Chandler (2001) appears to have been incorrect ( Webb 2004).