Rhexoza Enderlein

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 : 43-44

Rhexoza Enderlein

( Figs. 4–5 )

Rhexoza Enderlein, 1936: 55 . Rhexosa authors, misspelling.

Type –species. Rhexoza zacheri Enderlein, 1936 (synonym of R. subnitens Verrall teste Cook, 1956a: 4); Cook, 1972: 632; Cook, 1981: 319.

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 setose along anterior margin. No incomplete false r–m vein on M1. No pretergites 3, sternites 2–4 unsclerotized. Male sternite 7 trapezoid, with a posterior mesal incision. Aedeagus with a pair of lateral projections on which the parameres articulate, aedeagal plate absent; gonostylus lost; wide tergite 9, more or less dorso–ventrally compressed, not divided by a posterior mesal incision, parameres short, with distal setae ( Figs. 4–5 ).

Discussion. R. subnitens (Verrall) can be differentiated from other genera of Swammerdamellini mainly on the base of male terminalia features: the rather wide tergite 9, not divided by a posterior mesal incision, and the rounded and short parameres, with distal setae ( Figs. 4–5 ). Other features in the head, thorax and wing are quite plesiomorphic and are, shared with other genera of the tribe, as the shape of the maxillary palpus, the absence of pretergites on tergite 3, the presence of sternites 5–6 sclerotized, the 2–4 unsclerotized, loss of the gonostylus, and the Y–shaped sternite 9 in an anterior position ( Amorim, 1982). A revision of the Palearctic species of Rhexoza would be desirable for a more definite solution for the problem of the genus. Rhexoza richardsi ( Freeman, 1985) known from England, and R flixella ( Haenni, 2001) , known from Switzerland, seem to fit quite comfortably with the type –species in the genus. Rhexoza lydiae , described from southern France ( Withers, 2004), also seems to belong in the genus, even though the original description has not a lateral view of the male terminalia and lacks some other details of thorax and abdomen sclerites. R. radiella (Enderlein) , from Tunesia, is known only from the female and its position cannot be properly discussed at this time. The same applies to Rhexoza seminitens (Edwards) , from Borneo. Both these species for the time being are kept in Rhexoza s.s.

Species included. Palearctic: R. subnitens (Verrall, 1886) ; R. richardsi Freeman, 1985 ; R. flixella Haenni, 2001 ; R. lydiae Withers, 2004 . Species doubtfully included in the genus. Palearctic: R. radiella ( Enderlein, 1926) . Oriental: R. seminitens ( Edwards, 1928) .

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).