Tanypezidae

Field: Agricultural and Biological Sciences (Life Sciences)

The Tanypezidae Except in the classification of Griffiths (1972), the Tanypezidae have generally been referred to the superfamily Diopsoidea (or its equivalent under other names). The alternative association between Tanypezidae and " Heteromyzidae " proposed by Griffiths has been discarded (D. McAlpine, 1985) as based on convergent character states or on apomorphies which may date too far back in the phylogenetic history of the Schizophora to be classed as synapomorphies for this particular association. Heteromyza and allied genera almost certainly represent a particular development within the tribe Heleomyzini (sensu D. McAlpine) of the Heleomyzidae. Modern authors, following Hennig (1958), have generally considered that the genus Strongylophthalmyia forms a monophyletic group with the more typical tanypezids. Following Colless & D. McAlpine (1970) and Griffiths (1972), I prefer to include Strongylophthalmyia in the Tanypezidae, despite the obvious differences, because of their close agreement in many structures. Some differences between Tanypezidae and Strongylophthalmyiidae given by J. McAlpine (1989) apply for the separation ofNew World forms, but not or less accurately for separation of some Old World species of Strongylophthalmyia, which are more morphologically diverse. The Tanypezidae do not show clear morphological evidence of close relationships to any other family of Diopsoidea, though they provide a mixture of features of several of these families; e.g., the presence of a mesopleural bristle is shared only with Nothybidae, and the presence of a subcostal break in the costa and of divergent postvertical bristles agrees with the groundplan of the Psilidae. The presence of prothoracic precoxal bridges agrees with taxa of several diopsoid families, but the details of shape and contour of the prosternum, with its broad, ventrally exposed bridges, can be very like those of Gobrya, particularly in some Strongylophthalmyia species. However, as I can find no other significant points of resemblance between Gobrya and Tanypezidae, I interpret the resemblance as probably due to convergence. The tanypezid Neotanypeza dallasi (Shannon) and several Strongylophthalmyia species have a well differentiated presutural bristle, and the former also has a posterior intra-alar ("inner postalar") and some well developed posteroventral bristles on the distal part of the fore femur. These look like the homologues of the bristles so named in certain taxa of Heleomyzoidea, Nerioidea, Tephritoidea, and other superfamilies, but such bristles do not occur in more typical diopsoid flies. (The true postalar bristle in the Diopsidae approximates in position to the intra-alar in other taxa. See autapomorphy (c) for that family). The structure and relations of antennal segments 2 and 3 in Tanypezidae are much more like those of many taxa of Nerioidea than of any other Diopsoidea (except for the almost certainly derived condition in Diopsidae). The facial structure is unlike that of any other Diopsoidea and typical of the Nerioidea (e.g., certain Pseudopomyzidae, Neriidae, etc., see D. McAlpine, 1996). The strongly recurved anal crossvein (transverse section of CUA2 or of CuA) is unlike that of any other diopsoid fly, but is similar to that of the pseudopomyzid genera Heloclusia and Latheticomyia, which I have regarded as somewhat primitive taxa of Nerioidea. However, no undoubted nerioid fly known to me has a prosternal structure remotely resembling that of Tanypezidae. In Strongylophthalmyia spp. segment 7 of the female has the tergite and sternite fused by elimination of the pleural membrane, but the segment becomes desclerotised posteriorly. In Tanypeza (see Steyskal, 1987a: fig. 4) sclerotisation of segment 7 is represented by two pairs of longitudinal strips. Neither of the above conditions is typical of the Diopsoidea, but that of Strongylophthalmyia is not far from that of the Nerioidea, in which the tergite and sternite are fused to form an oviscape. The condition in Tanypeza may be derived either from that of Strongylophthalmyia or from a more plesiomorphic condition in which a separately sclerotised tergite and sternite have each been divided longitudinally. While I do not claim to understand the relationships of the Tanypezidae to other taxa of Schizophora, were I to make an arbitrary superfamily assignment of the family on the basis of least improbability, this assignment should probably be to the Nerioidea.