Abrhexosa Freeman

Amorim, Dalton De Souza, 2007, Two new genera of Swammerdamellini (Diptera, Scatopsidae), with a discussion of the position of the species of Rhexoza, Zootaxa 1640, pp. 41-53 : 46

Abrhexosa Freeman

( Figs. 8–10 )

Abrhexosa Freeman, 1990: 18 .

Type –species. Scatopse thripsoides Edwards, 1928 (orig. des.).

Diagnosis. A single whorl of setae on flagellomeres, maxillary palpus large, cardo–stipes mesally fused. Distal end of postmentum projected between the labella. Pronotal apodeme curved, katepisternum bare ventrally. No incomplete false r–m vein on M1. No pretergites 3, sternites 2–4 unsclerotized. Male sternite 7 trapezoid, with a posterior mesal incision and a pair of lateral projection and a differentiated ventral projection. Aedeagal plate absent, aedeagus opening at the end of a long, coiled projection; tergite 9 laterally compressed, straight dorsally and rounded distally ( Figs. 8–10 ).

Discussion. This genus was erected by Freeman (1990) for a single Oriental species described by Edwards (1928). In the original description of Abrhexosa Freeman (1990) already called attention for the similarities shared by that species with Rhexoza and Akorhexoza , especially the shape of the maxillary palpus and the unsclerotized abdominal sternites 2–4. Freeman (1990), however, noted that the reduction in the extension of the radial sector of the wing, the shape of the female sternite 8 and of the male gonocoxites would be enough to justify a separated genus for the type –species. Actually, some of the Nearctic species previously included in Rhexoza and the Neotropical species R. panamensis fit in Abrhexosa , since they share these apomorphic features. The male terminalia of all these species do not present an aedeagal plate and the aedeagus opening is at the end of a long, usually coiled tube. Parameres are also elongated and rather compressed distally ( Amorim, 1982). These features seem to be synapomorphic for the genus and allow some confidence in their inclusion with the type –species in Abrhexosa .

Species included. Oriental: A. thripsoides ( Edwards, 1928) . Nearctic: A. amaryllis ( Cook, 1975) , n.comb.; A. ryckmani ( Cook, 1975) , n.comb.; A. grossa (Cook, 1956) , n.comb. Neotropical: A. panamensis (Cook, 1956) , n.comb.

Figures

FIGURES 8 – 16. Male terminalia of Swammerdamellini genera. 8 – 10. Abrhexosa panamensis (Cook). Male holotype (8, ventral; 9, lateral, 10, dorsal). 11 – 13. Quateiella sp. 1 (11, ventral; 12, lateral, 13, dorsal). 14 – 16. Cooka similis (Beekey). Male paratype (14, ventral; 15, lateral, 16, dorsal).