Psellidotus undetermined

Fachin, Diego Aguilar, Zichinelli, Marcela Maria Parada & Barrett, Bolívar Rafael Garcete, 2022, An illustrated checklist of Stratiomyidae (Diptera: Brachycera) from Paraguay with three new synonyms and 22 new records of species for the country, Zootaxa 5190 (1), pp. 1-55 : 34

sp. 1 ( Figs 99–100 )

Material examined. Paraguay: 1 ♂, Cordillera, Tobatí, Cerro Tobatí , 25.280121°S 57.093134°W, 28–29.i. 2015, 170 masl, B. & N. Garcete coll. ( MNHNPY; MNHNP-HX 2086). 1 ♀ , San Pedro, Cororo-Rio Ypane , 01–04.xii.1983, Malaise trap, M. Wasbauer coll. ( CSCA) .

Distribution. Paraguay (Cordillera: Tobatí; San Pedro: Cororo-Rio Ypane).

Comments. This species resembles the two species of Hedriodiscus Enderlein, 1914b : H. pulcher ( Wiedemann, 1824) and H. quadrilineatus ( Macquart, 1834) . According to Woodley (2009), both genera ( Hedriodiscus and Psellidotus Rondani, 1863 ) correspond to a heterogeneous group of species and a revision of their generic limits might place some of their species in other/new genera. Their separation is often based on the presence or absence of the crossvein r–m and in the number of flagellomeres. Hedriodiscus does not have a crossvein r–m, therefore the discal cell is fused to the radial sector, and the antenna is often shorter, with six well-discernible flagellomeres, in which the sixth is clearly slender than the fourth. Psellidotus , on the other hand, has a crossvein r–m and the antenna is a bit longer, with five or six flagellomeres ( James & McFadden 1979: 9; Woodley 2009: 534), in which the last two can be indistinctly separated from each other and as wide as the previous flagellomere. Although similar in the overall body color pattern, particularly over the thorax, with H. quadrilineatus ( Lagrange 1993: 71, fig. 22), our Psellidotus sp. 1 ( Figs 99–100 ), same as for Psellidotus sp. 2 , has a longer antenna, in which the flagellomeres 4–6 or 5–6 (if the fourth is fused to the fifth) are only slightly tapered, without difference in diameter between the last two and the previous flagellomere. Furthermore, both Psellidotus species have a short crossvein r-m and they do not have a developed fronto-facial prominence with the antennae inserted at the apex, as seen in the two species of Hedriodiscus revised by Lagrange (1993).

Figures

FIGURES 97–102. Stratiomyid species, habitus dorsal. 97. Odontomyia fiebrigi Lindner, 1976, female. 98. Promeranisa nasuta (Macquart, 1850), male. 99–100. Psellidotus sp. 1, male and female, respectively. 101–102. Psellidotus sp. 2, male and female, respectively. Scale bar, 1 mm.