Diopsoidea Billberg 1820
Creators: name: McAlpine, David K.
Publisher: name: Zenodo
Year: 1997
Subjects: Biodiversity
Taxonomy
Plantae
Diptera

description: The superfamily Diopsoidea (syn. Nothyboidea) The Nothybidae and Psilidae Acz6l (1955) placed the Nothybidae in a separate superfamily, Nothyboidea, from all other Schizophora, because he thought it was the only schizophoran group with the male postabdomen symmetrical and therefore not circumverted. In this he was mistaken, for in many schizophoran families the male postabdomen (particularly in the more or less reduced protandrial segments 6-8) is symmetrical (e.g., Conopidae, Drosophilidae, Ephydridae, Lauxaniidae, Psilidae, Teratomyzidae, etc.). The Dolichopodidae, in which the protandrium possesses groundplan asymmetry, includes also forms with secondary symmetry (D. Bickel, pers. comm.). This is no longer taken as evidence of lack of circumversion of the genital segment, at least historically, in these taxa (see Hennig, 1958; Griffiths, 1972). Hennig (1958) employed the superfamily Nothyboidea to include the families Diopsidae, Nothybidae, Megamerinidae, Tanypezidae, Strongylophthalmyiidae, and Psilidae, although he was unable to find a single apomorphy to establish monophyly of the superfamily. J. McAlpine (1989) recognised the same superfamily concept as Diopsoidea (on grounds of nomenclatural priority), with the addition of Somatiidae and Syringogastridae. J. McAlpine (1989) considered the Diopsoidea and Nerioidea to be sister groups, but I have found no validity in the evidence presented (D. McAlpine, 1996). Griffiths (1972) used a revised concept of the Nothyboidea to include only the families Nothybidae, Psilidae, Teratomyzidae, and Periscelididae (the last including <i>Somatia</i> but not <i>Cyamops</i> and <i>Stenomicra).</i> I do not find the four stated groundplan apomorphies at all convincing as support for his superfamily concept. Among such a diverse lot of taxa, only unusually distinctive apomorphies can provide acceptable evidence for interrelationships, and these four are very widely distributed among acalyptrate families and undoubtedly subject to convergence. Griffiths also suggested, but simultaneously queried, a sister group relationship between Nothybidae and Teratomyzidae (1972, fig. 16, and accompanying table), supported by the following three apomorphies (from his more extensive listing for nothyboid families): 1, postvertical bristles reduced; 5, axillary lobe and alula reduced; 7, lower basal cell (bm) open anterodistally. These do not appear to provide a set of primal synapomorphies, because the postvertical bristles, though absent in Nothybidae, are well developed but rather short in the groundplan of Teratomyzidae; the alula is not as much reduced in the groundplan of Teratomyzidae as it is in many other taxa of elongate acalyptrate flies; the cell bm is not open anterodistally in the Teratomyzidae, but vein 4 has a flexure or weak point in this region. I find such a weakening or flexure in the basal section of vein 4 to be manifested to a variable degree in some taxa of Agromyzidae, Coelopidae, Heleomyzidae, Helosciomyzidae, Pallopteridae, Platystomatidae, Psilidae, Sepsidae, Tephritidae, and Tethinidae. The Teratomyzidae, which have been the subject of a recent study (D. McAlpine &amp; de Keyzer, 1994), are widely different from the Nothybidae in their morphology, except for the simplified, symmetrical protandrium; also the aedeagal characters, which Griffiths considered significant for placement in the Nothyboidea, are quite diverse among the teratomyzids and their groundplan conditions for the family are uncertain. I consider that there is no case for considering the Nothybidae and Teratomyzidae to be closely related. The Nothybidae and Psilidae show some interesting points of morphological resemblance. There is an enlarged postocular bristle laterad of the outer vertical in <i>Nothybus</i> and in several psilid genera (so that it may be present in the groundplan ofboth families). There are, however, some difficulties in establishing homologies of bristles on the upper part of the head in both families, as indicated by Hennig (1958). There is a general resemblance in antennal structure between Nothybidae and Psilidae, but a more detailed resemblance between Nothybidae and <i>Gobrya,</i> as indicated below. The anterior notopleural bristle is absent in Nothybidae and Psilidae, as in many other elongate flies (see D. McAlpine, 1997). The apparent groundplan for both Nothybidae and Psilidae includes a secondarily symmetrical male abdominal segment 6 with ventrally placed sternite. The groundplan for both families probably includes a largely membranous distiphallus which is ribbonlike and almost symmetrical. The most likely synapomorphies for Nothybidae and Psilidae would seem to be in the male postabdominal conditions indicated, the subcircular prothoracic spiracle not largely closed over by intermeshed hairs on its outer lips, and the enlarged postocular bristle. As indications of relationship these seem to conflict with the evidence for relationship between <i>Gobrya</i> and Nothybidae reviewed below. Some of the numerous character states of Nothybidae which differ from those of Psilidae (the latter bracketed) are as follows: (l) distal articular surface of antennal segment 2 facing forwards (facing downwards); (2) lateral arms of ptilinal fissure much abbreviated (moderately long and decurrent on parafacial); (3) prothoracic precoxal bridge extremely broad (absent); (4) subscutellum hypertrophied (not prominent, sometimes vestigial); (5) mesopleural bristle present (absent); (6) pleurotergite setulose, without noticeable pubescence (pubescent, without setulae); (7) tibiae with setulae all aligned in several longitudinal series (tibial setulae irregularly placed); (8) subcosta completely sclerotised distally, terminating in costa close to termination of vein 1 (subcosta desclerotised distally, terminating well before end of vein 1); (9) first and second basal cells partly confluent (completely separated); (l0) alula absent (present); (11) female with spermathecal vesicles (spermathecal vesicles absent,?consistently). In many of these characters the Nothybid state is apomorphic relative to the psilid state, but the psilids are apomorphic in characters 8 (at least partly) and 11. In characters 1, 5, and 6, polarity is uncertain, and, ifNothybidae and Psilidae are not sister-groups, it may not be reasonable to regard a character state present in one family as necessarily directly derived from that of the other. An intriguing possibility, which I cannot at present regard as a probability, is the following: the Nothybidae are not closely related to any of the families here placed in the Diopsoidea, but are derived from near the Curtonotidae in the superfamily Ephydroidea (syn. Drosophiloidea). Because I cannot completely refute this idea, I point out some evidence for and against it. The Curtonotidae are considered to include the genera <i>Curtonotum, Cyrtona,</i> and <i>Axinota.</i> The following 13 conditions (a-m) could be considered to give some support to this hypothesis. (a) The antennal structure of Nothybidae, described above, agrees with that of <i>Curtonotum</i> in most details, as it does with most diopsoids (other than Diopsidae). (b) In Nothybidae and Curtonotidae the external opening of the prothoracic spiracle is subcircular, instead of having the usual narrowly two-lipped conformation. This feature does not, however, give a separation from Psilidae, as mentioned above. (c) The scutellum in Nothybidae has two pairs oflarge bristles on its margins. This agrees with Curtonotidae and most other ephydroid taxa, but in the typical diopsoid taxa there is only one large pair of scutellar bristles, the apical pair, and any others are much smaller. (d) While Nothybidae are noted for the prominently hypertrophied subscutellum, that of <i>Curtonotum</i> more nearly approaches the nothybid condition than any other taxon included in the Diopsoidea. (e) The presence of a mesopleural bristle in Nothybidae is in disagreement with other taxa here placed in Diopsoidea, but one or two mesopleurals are present in many taxa of Ephydroidea, including the Curtonotidae, but not the Drosophilidae. A mesopleural bristle is so widely present among schizophoran taxa, that its presence does not constitute a very particular point of agreement for the above families. (f) The setulae on the tibiae in Nothybidae and Curtonotidae are arranged in longitudinal rows, a condition present in many other ephydroids. However, this character does not give a good separation from other taxa of Diopsoidea, many of which show a tendency for these setulae to become seriate. (g) The tarsi of Curtonotidae (least so in <i>Cyrtona)</i> are, like those of Nothybidae, remarkably long, slender and subcylindrical. In most other diopsoids the tarsi are either somewhat shorter, in relation to the tibiae, or somewhat more depressed. (h) The subcosta in Nothybidae, as in <i>Curtonotum,</i> is fully developed to its distal termination in the costa very near but quite separate from the end of vein 1. The variations in subcostal development in other diopsoid taxa do not include these precise features. (i) In both the Nothybidae and Curtonotidae the anal region of the wing, immediately beyond the alular region, is narrowed, the margin here showing more or less concave curvature, and the much shortened but sclerotised distal section of vein 6 ends at or near the margin Although basal wing-narrowing occurs in other diopsoid families, it does not follow this pattern. I note here that J. McAlpine (1989) was mistaken in considering vein 7 (A2) to be visible in this region in both Curtonotidae and Cryptochetidae. The correct identities of the anal veins in these flies, as given by Hennig (1958), become apparent when the curtonotid genera are carefully compared with the less reduced forms of Drosophilidae. The structure in <i>Cyrtona</i> illustrates the true position of vein 6 and also shows how a secondary spur is liable to misidentification as vein 6 in the Cryptochetidae. I affirm that there is no trace of vein 7 beyond the alular region in any taxon of either Diopsoidea or Ephydroidea. (j) In both Nothybidae and Curtonotidae there is a convex longitudinal crease of the wing membrane arising just beyond the origin of the distal section of vein 6. This crease is not the homologue of any true vein, and is not known to me in other taxa of Diopsoidea, though there is a trace of it in a few other ephydroid taxa, e.g., Diastatidae. (k) In the male postabdomen of Nothybidae and Curtonotidae there is a somewhat similar degree of reduction of sclerites of segments 6 to 8, in contrast to the large tergite and sternite 5, with a tendency towards symmetry. (1) The male genital segment of Nothybidae and Curtonotidae is directed posteriorly, in contrast to that of most taxa of Diopsoidea and Ephydroidea, in which the genital segment is directed ventrally. In the diopsoid family Psilidae there is also a strong tendency for the genital segment to be directed posteriorly. (m) Pollock (1996) has recorded ovoviviparity in the curtonotid <i>Cyrtona,</i> a condition which it shares with <i>Nothybus longithorax</i> Rondani. This is apparently an infrequently derived condition in acalyptrate taxa, the few other known cases being listed by Pollock. However, it is not known if it is a groundplan condition for either Nothybidae or Curtonotidae. Of the above arguments, (a), (b), (f), (k), (1), (m) may be seen as rendering relationships of Nothybidae to Ephydroidea as feasible as to Diopsoidea, while (c), (d), (e), (g), (h), (i), (j) may, to varying degrees, be seen as favouring the hypothesis of ephydroid relationships (with particular reference to the Curtonotidae) over that of diopsoid relationships. The above indications of possible relationship between Nothybidae and Curtonotidae seem to be countered by the following points, (n) to (s), which are more in accordance with diopsoid relationships for the Nothybidae. (n) The Nothybidae lack the postvertical bristle, vibrissa, and seriate postocular setulae, as in <i>Gobrya,</i> Syringogastridae, and Diopsidae. Such a degree of reduction of cephalic bristles is unusual in the Ephydroidea and not found in the Curtonotidae. (0) The Nothybidae lack the humeral, anterior notopleural, presutural, and sternopleural bristles. This reduction of thoracic bristles is in disagreement with Curtonotidae and most less reduced ephydroids, but is typical of the Diopsoidea. (P) The Nothybidae lack the preapical dorsal tibial bristle, characteristic of the Curtonotidae, Diastatidae and many drosophilids, but uniformly absent in Diopsoidea. (q) The costa in Nothybidae lacks the break at the subcostal position. This condition disagrees with probably all macropterous Ephydroidea, but agrees with the diopsoid taxa other than Psilidae. (r) In the Nothybidae the basal end of the discal cell is strongly enclosed, but the second basal cell is confluent with the first basal cell because of an extensive break in vein 4. This condition contrasts with that in Curtonotidae, where vein 4 is complete but the basal end of the discal cell is confluent with the second basal cell. In those ephydroids with discal and second basal cells visibly separated, the basal crossvein separating them is generally weakly sclerotised. This difference between Nothybidae and typical ephydroids is most readily explained as an independent derivation of each condition from a plesiomorphic condition with both basal cells completely enclosed by well sclerotised veins, as in the Psilidae. A similar pattern of variation in these cells at a lower taxonomic level occurs in the family Neurochaetidae, where the two different apomorphic conditions distinguishing the genera <i>Neurotexis</i> and <i>Neurochaeta</i> have been separately derived from the plesiomorphic condition found in <i>Anthoclusia</i> and <i>Neurocytta</i> (D. McAlpine, 1993). (s) the Nothybidae lack the incomplete suture between abdominal tergites 1 and 2, present in the Curtonotidae and other less reduced forms ofEphydroidea. This suture is absent in all typical families of Diopsoidea. For the above reasons I leave the Nothybidae in the provisional superfamily Diopsoidea. The problem of relationships between Nothybidae and <i>Gobrya</i> will be discussed below. The Syringogastridae and Diopsidae The neotropical genus <i>Syringogaster</i> was generally placed in the Megamerinidae until Prado (1969) erected for it the family Syringogastridae in a detailed taxonomic review. Griffiths (1972) regarded the Syringogastridae as the sister group of the Diopsidae (including Centrioncinae), the two families together forming his "prefamily Diopsoinea". J. McAlpine (1989) accepted family status for Syringogastridae, but placed it as a sister group of Megamerinidae (including <i>Gobrya),</i> a classification I consider too improbable for further consideration (see D. McAlpine, 1997). I accept that Syringogastridae and Diopsidae (including Centrioncinae) are sister groups on the basis of a different set of synapomorphies from those given by Griffiths. I review the eight autapomorphies listed by Griffiths (1972) in support of monophyly of the Diopsoinea as follows, drawing comparisons with other families (numbering as given by Griffiths except that characters (2) and (4) are separated into their components): (1) <i>Postvertical bristles absent.</i> This is an apomorphy relative to the plesiomorphic state of Psilidae, but, because the apomorphic state is present in the groundplan of outgroups Nothybidae and <i>Gobrya,</i> it cannot be claimed as a primal autapomorphy for Diopsoinea (synapomorphy for Syringogastridae and Diopsidae <i>sensu</i> Hennig, 1965). (2a) <i>Only one fronto-orbital (ors)... present.</i> This is perhaps an apomorphy relative to the presence of two pairs of fronto-orbital bristles, which is perhaps a groundplan plesiomorphy for the Psilidae. The outgroup Nothybidae is subject to interpretation as having one, two, or three fronto-orbitals. Doubt as to whether the foremost frontal bristle of Nothybidae is the homologue of a fronto-orbital (supraorbital) bristle arises from its unusual position, but the doubtfully inferred presence of three fronto-orbitals (Hennig, 1958: fig. 54) seems not to rest on any firm evidence. <i>Syringogaster</i> has no fronto-orbital bristles, like <i>Gobrya,</i> but there is no evidence as to whether the condition in the former was attained by loss of a single such bristle or by simultaneous reduction of two bristles. For these reasons I am doubtful if the inferred presence of one pair of fronto-orbitals in the groundplan of Diopsoinea is an autapomorphy. (2b) <i>Only... one vertical bristle (vte) present.</i> This could be a valid autapomorphy, though its interpretation is disputed by Feijen (1989) on improbable grounds. @ <i>Only one postalar bristle present.</i> As this condition is present in the outgroups Nothybidae, Psilidae, and <i>Gobrya,</i> it cannot be claimed as a primal autapomorphy for Diopsoinea. (4a) <i>First and second abdominal terga fused, forming syntergum which is the largest sclerite of the abdomen.</i> Partial fusion of tergites 1 and 2 is evidently present in the groundplan of the Schizophora. As complete fusion is present in all likely diopsoid outgroups (Somatiidae excluded) this cannot be claimed as an autapomorphy for Diopsoinea. (4b) <i>Basal segments of abdomen (especially the second segment) elongate, but distal segments becoming short and wide, so that the abdomen has a petiolate appearance.</i> This condition is present in the outgroup <i>Gobrya</i> and to a varying extent in many elongate acalyptrate flies of various families. <b>In</b> several primitive diopsid genera the condition is only slightly developed. Hence its status as an autapomorphy for Diopsoinea is unconvincing. <i>(5) Seventh sternum (male) forming complete ventral band of sclerotisation, fused with inverted eighth sternum on right side...</i> This may be a genuine autapomorphy but it needs more investigation within the Diopsidae where sternite 7 is variable. The fusion of a ventrally placed sternite 7 with sternite 8 on the right side does not occur in outgroups. <i>(6) Seventh and eighth tergum vestiges (male) lost.</i> This is the condition in all diopsoid families and most other families of Schizophora. It is therefore illogical to give it as an autapomorphy for Diopsoinea. <i>(7) Seventh left spiracle (male) lying within seventh sternum.</i> While this condition may be in the groundplan of Diopsoinea, its presence in <i>Gobrya,</i> which otherwise has a rather different protandrium (Fig. 8), precludes its recognition as a primal autapomorphy for Diopsoinea. (8) <i>Aedeagus (male) rather short, with a complex distal section which bears lobes or processes.</i> There is a strong resemblance between the aedeagi <i>ofSyringogaster</i> and certain diopsids (compare figs 79 and 80 of Griffiths, 1972, and the figures of <i>Sphyracephala</i> spp. of Feijen, 1989), even though homology of individual lobes has not been demonstrated. This condition, according to the above general description, occurs also in <i>Gobrya</i> (Fig. 12), but not in the investigated taxa of Nothybidae and Psilidae. The evidence suggests that this condition of the aedeagus may be a synapomorphy for <i>Gobrya</i> and Diopsoinea, rather than an autapomorphy for Diopsoinea. Despite the above arguments, I believe that the taxa constituting Griffiths' Diopsoinea together form a monophyletic group as indicated by t
description: Published as part of <i>McAlpine, David K., 1997, Gobryidae, a new family of acalyptrate flies (Diptera: Diopsoidea), and a discussion of relationships of the diopsoid families., pp. 167-194 in Records of the Australian Museum 49 (2)</i> on pages 168-175, DOI: 10.3853/j.0067-1975.49.1997.1264, http://zenodo.org/record/4655129
description: {"references": ["Hennig, w., 1958. Die Familien der Diptera Schizophora und ihre phylogenetische Verwandtschaftsbeziehungen. Beitrage zur Entomologie 8: 505 - 688.", "Griffiths, G. C. D., 1972. The phylogenetic classification of the Diptera Schizophora with special reference to the structure of the male postabdomen. 340 pp. W. Junk, The Hague.", "McAlpine, J. F., 1989. Phylogeny and classification of the Muscomorpha. In J. F. McAlpine (editor): Manual of Nearctic Diptera 3: 1397 - 1578. Canadian Government Publishing Center, Hull, Quebec.", "McAlpine, D. K., 1996. Relationships and classification of the Pseudopomyzidae (Diptera: Nerioidea). Proceedings of the Linnean Society of New South Wales 116: 223 - 232.", "McAlpine, D. K., &amp; R. G. de Keyzer, 1994. Generic classification of the fern flies (Diptera: Teratomyzidae) with a larval description. Systematic Entomology 19: 305 - 326.", "McAlpine, D. K., 1997. Relationships of the Megamerinidae (Diptera: Nerioidea). Beitrage zur Entomologie 47: 465 - 475.", "Pollock, J. N., 1996. Viviparous adaptations in the acalyptrate genera Pachylophus (Chloropidae) and Cyrtona (Curtonotidae) (Diptera: Schizophora). Annals of the Natal Museum 37: 183 - 189.", "McAlpine, D. K., 1993. Review of the upside-down flies (Diptera: Neurochaetidae) of Madagascar and Africa, and evolution of neurochaetid host plant associations. Records of the Australian Museum 45: 221 - 239.", "Prado, A. Pires do, 1969. Syringogastridae, uma nova familia de dipteros Acalyptratae, corn a descricao de seis especies do genero Syringogaster Cresson. Studia entomologica 12: 1 - 32.", "Hennig, W., 1965. Dia Acalyptratae des Baltischen Bernsteins und ihre Bedeutung flir die Erforschung der phylogenetischen Entwicklung dieser Diptera-Gruppe. Stuttgarter Beitrage zur Naturkunde 145: 215 pp.", "Feijen, H. R., 1989. Diopsidae. In G. C. D. Griffiths (editor): Flies of the Nearctic Region 9 (12): 122 pp. E. Schweizerbart'scre Verlagbuchhandlung, Stuttgart.", "McAlpine, D. K., 1991. Review of the Australian kelp flies (Diptera: Coelopidae). Systematic Entomology 16: 29 - 84.", "Castro, L. E. de, 1953. Estudo comparativo das cerdas cuneiformes das pemas dos drosofilideos (Diptera). Revista Brasileira de Biologia 13: 363 - 368.", "Feijen, H. R., 1981. A review of Diopsina Curran, 1928 (Diptera: Diopsidae), with a note on Cyrtodiopsis. Annals of the Natal Museum 24: 465 - 482.", "Feijen, H. R., 1983. Systematics and phylogeny of Centrioncidae, a new afromontane family of Diptera (Schizophora). Zoologiscre Verhandlung 202: 137 pp.", "Steyskal, G. C., 1972. A catalogue of species and key to the genera of the family Diopsidae (Diptera: Acalyptratae). Stuttgarter Beitrage zur Naturkunde 234: 20 pp.", "Cumming, I. M., B. J. Sinclair &amp; D. M. Wood, 1995. Homology and phylogenetic implications of male genitalia in Diptera- Eremoneura. Entomologica scandinavica 26: 121 - 151.", "Shillito, J. F., 1971. The genera of Diopsidae (Insecta: Diptera). Zoological Journal of the Linnean Society 50: 287 - 295.", "Steyskal, G. C., 1970 a. Notes on the postabdomen and variation in Centrioncus prodiopsis Speiser (Diptera: Diopsidae). Proceedings of the Entomological Society of Washington 72: 325 - 327."]}