Ecitophora halterata (Borgmeier) Borgmeier, 2005

Disney, R. Henry L., 2005, Rudimentary halteres of some flightless female Phoridae (Diptera) reassessed, and some taxonomic implications, Zootaxa 1042, pp. 39-54 : 40-41

Ecitophora halterata (Borgmeier) comb. nov.

( Figs 1 , 3–7 )

Ecituncula halterata Borgmeier, 1936: 32 .

Ecitophora breviptera Disney, 1989 (in Disney & Kistner, 1989: 164). Syn. nov.

Borgmeier (1960) commences his diagnosis of the females of Ecituncula Schmitz by stating unequivocally that they lack wing rudiments. However, he reported that an included species, E. halterata Borgmeier (1936) , retains its halteres. Carl Rettenmeyer’s material that I have examined includes large samples preserved in alcohol, from Costa Rica and from Panama, of Ecituncula halterata determined by Borgmeier. I have mounted many of these specimens on slides. These serve to indicate that Borgmeier mistook the haltere shaped wing rudiments of this species for halteres. The consequence was that subsequently collected specimens would not run to the genus Ecituncula , which lack wing rudiments according to Borgmeier, but keyed out at Ecitophora instead. However, a series with similar distinctive, haltere­like, wing rudiments, E. breviptera Disney , had already been assigned to this genus and proves to be indistinguishable from the E. halterata material from Panama, determined by Borgmeier as E. halterata , but a little different from most of his specimens from Costa Rica (see below). It is incontrovertible that these haltere­like structures are situated at the posterolateral extremities of the mesothorax, well separated from the metathoracic spiracles ( Fig. 1 ). They are undoubtedly wing rudiments that happen to resemble halteres, but lacking the basal fields of sensilla that characterise halteres and lack the hairs of typical Ecitophora wing rudiments (e.g Fig. 2 ). Furthermore the possession of both wing rudiments and scutellar bristles (s in Fig. 1 ) means that E. halterata was the only species of Ecituncula reported to possess scutellar bristles. It is therefore proposed that it be transferred to Ecitophora , so that it should now be called Ecitophora halterata (Borgmeier) .

This species proves to be somewhat variable. Prior to the above recognition that Borgmeier had misinterpreted the wing rudiment as a haltere, E. breviptera was described from Guatemala and Costa Rica, and its wing rudiment illustrated (W in Fig. 1 ). Subsequently a further series from Costa Rica was reported ( Disney & Kistner, 1998) but it was noted that the wing rudiments were a little longer (cf Figs 3 and 4 ). The study of Rettenmeyer’s material has also revealed that only specimens with shorter rudiments were found in Panama but mainly specimens with longer rudiments were found in Costa Rica. Furthermore a few specimens from Costa Rica had even longer rudiments ( Fig. 5 ). The relative development of abdominal tergites 2–4 also varied, with T3 often represented by hairs only and T4 tending to be less complete in those specimens with shorter wing rudiments; but this correlation was not consistent. Likewise there are small variations in the precise positions of the frontal bristles and their relative strengths. For example the pre­ocellars may be weaker than the mediolateral bristles or these bristles may be subequal. The possibility of a polymorphism in the size of the wing rudiments cannot be ruled out, as such a polymorphism occurs in Metopina ciceri Disney (1988) . Another possibility is that these three states of the wing rudiments represent sibling species. However, one specimen from Costa Rica has its right wing rudiment as Fig. 7 and left rudiment as Fig. 6 . This difference within a single specimen suggests that the variation in the sizes of the wing rudiments represents intraspecific variation. A consequence of opting for this hypothesis is that E. breviptera becomes a synonym of E. halterata . I herewith formally propose this synonymy, with the reservation that further data may not support it. The hypothesis could be tested by the use of molecular data on freshly collected material suitably preserved for such an investigation.

Figures

FIGURE 1. Ecitophora halterata female, right side of thorax from above (H = head, S = scutellar bristle, W = wing rudiment, A = abdomen). Scale bar 0.1 mm.

FIGURES 2 – 7. Ecitophora females, wing rudiments: (2) E. collegiana, right rudiment; (3 – 7) E. halterata: (3 – 5) right rudiments of three different specimens; (6 – 7) Left and right rudiments of a single specimen. Scale bars = 0.1 mm.