Pararhexosa 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 : 43

Pararhexosa Freeman

( Figs. 1–3 )

Pararhexosa Freeman, 1990: 14 .

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

Diagnosis. A single whorl of setae on flagellomeres, maxillary palpus relatively short, cardo–stipes not fused mesally. Distal end of postmentum not projected between the labella. Pronotal apodeme straight, katepisternum bare along anterior margin. R5 long, in some species an incomplete false r–m vein on M1 or at least an angle on M1. Pretergite 2 present, pretergite 3 absent; sternites 2–6 sclerotized. Male sternite 7 rectangular, without a posterior mesal incision. Aedeagus without lateral projections on which the parameres articulate, no projection distal to aedeagus opening (aedeagal plate) ( Figs. 1–3 ).

Discussion. This genus was described by Freeman (1990) including only the type –species, P. flavipalpis , from Thailand. P. flavipalpis and some other species presently in Rhexoza are clearly plesiomorphic for some of the features modified in other Swammerdamellini genera, as Coboldia , Rhexoza , Akorhexoza , Quateiella , and Abrhexosa , e.g., the well developed maxillary palpus with a reniform shape, the mesally fused cardo–stipes, the triangular shape of the labellar sclerite, the secondary presence of setae on the proepimeron and on the anterior margin of the katepisternum, the larger spiracular sclerite (i.e., the dorsal part of proepimeron), the presence of meral setae, the unsclerotized anterior abdominal sternites, the male terminalia laterally compressed, and a deep posterior incision in the tergite 9 ( Amorim, 1982). Amorim & Haenni (1996) examined the holotype of Scatopse tubifera Edwards , from Chile, and concluded that, even though the male was not known, the species was plesiomorphic for these features and should be at least provisorily included in Pararhexosa . Rhexoza chelata Cook ( Figs. 1–3 ) and R. senticosa Cook , both from Australia, were examined in this study and fit in Freeman’s (1990) definition of the genus. They are also plesiomorphic for these features of more advanced Swammerdamellini. These species are herein formally transferred to Pararhexosa , which add to the type –species and to P. t u b i f e r a. Two other undescribed species from Chile also fit in the genus. Even though the inclusion of these species in Pararhexosa still does not guarantee a monophyletic genus, its placement here is more appropriate than in other genera of the tribe.

Species included. Oriental: P. flavipalpis ( Edwards, 1928) . Australian: P. c h e l a t a ( Cook, 1971), n.comb.; P. s e n t i c o s a ( Cook, 1971), n.comb. Neotropical: P. tubifera ( Edwards, 1930) ; Pararhexosa sp. 1 ( Chile), Pararhexosa sp. 2 ( Chile).

Figures

FIGURES 1 – 7. Male terminalia of Swammerdamellini genera. 1 – 3. Pararhexosa chelata (Cook), 1971. Male paratype (1, ventral; 2, lateral, 3, dorsal). 4 – 5. Rhexoza subnitens (Verrall). 6 – 7. Akorhexoza sp. 1 (4, ventral, 5, dorsal).