SYSTEMATIC STUDIES IN AUSTRALIAN PLATYSTOMATIDAE (DIPTERA) By David Kendray McAlpine, M.Sc. A thesis submitted for the degree of Doctor of Philosophy in the Faculty of Science of the University of London Imperial College of Science and Technology Department of Zoology and Applied Entomology{ South Kensington, London' S.W.7. October 1969 1 Abstract A general survey is made of the Australian flies of the family Platystamatidae on the basis of large collections of preserved material and type specimens in European museums. The development of the study of Australian Platystomatidae is reviewed, together with the present status of knowledge. Some information is provided on the biology and habits of the group. The distribution and abundance of the family in the zoogeographic regions of the world is described and particular attention paid to the distribution of genera occurring in Australia, both within and outside the Australian continent. The external morphology of the Platystomatidae is described in some detail and the principal trends in morphological diversity are outlined. The apparent relation— ships of the Platystomatidae to other families of Diptera are given together with their morphological basis. The family is defined and a scheme is presented for the division of the Platystomatidae into four subfamilies. The problem of defining geographically isolated species is examined and some new criteria are suggested. The desirability of recognizing subspecies is also examined. An attempt is made to analyze the relationship between specific sexual characters and isolating mechanisms and some new definitions of terms are proposed. Special attention is paid to the selective value of male genitalia characters. 2 The possible role of sexual characters in macroevolution is suggested. Some interesting specific sexual characters exhibited by certain of the Platystomatidae are described. A key to the Australian genera of Platystomatidae is given and a list of the known Australian species is presented. The genera Mesoctenia, Plagiostenopterina, Lamprogaster, Duomyia, and Euprosopia are defined. Keys to the 126 recognized Australian species of these five genera are provided together with descriptions of the species. Distributional data and, when available, habitat data are recorded for each species. 3 CONTENTS I Introduction (A)General Observations 5 (B)Historical and Present State of Knowledge 6 (C)Materials and Methods 10 (D)Acknowledgements 15 II Geographic Distribution 17 III Biology and Habits 24 IV Morphology (A)Introductory 30 (B)The Cuticular Surface 30 (C)The Head 35 (D)The Thorax 38 (E)The Abdomen 44 V Species Limits and Specific Characters (A)The Species Concept 52 (B)The Subspecies 60 (C)Evolutionary Role of Certain Taxonomic Characters 63 VI Relationships and Classification (A)Status and Relationships 104 (B)Subfamily Classification 111 (C)List of Australian Species, with Notes 115 (D)Key to Australian Genera 122 VII Genus Mesoctenia 128 4 VIII Genus Plagiostenopterina 134 IX Genus Lamprogaster 149 X Genus Duomyia 212 XI Genus Euprosopia 328 XII Summary 457 XIII Bibliography and References 462 XIV Index to Taxa 467 5 I. INTRODUCTION (A) General Observations The Platystomatidae are a family of two—winged flies (Diptera) found in most vegetated parts of the world with the notable exception of the temperate zone of South America. The number of known world species is slightly less than 1,000. The form and coloration of the insects are extremely varied. The spectacular form and colours of many of them have attracted collectors and in some areas, e.g. New Guinea, where the dipterous fauna as a whole is not well known, the Platystomatidae are comparatively well documented. On the other hand the numerous small and inconspicuous species of the family have not been collected and studied to the same extent. Until recently it was usual to regard the group as a subfamily of the family Otitidae (Ortalidae) but specialist opinion has now swung towards giving the Platystomatidae family rank. Though clearly related to other 'acalyptrate" families of Diptera, the very large squamae (calyptrae) of certain forms have led some authors to mistake them for calyptrates (e.g. Walker, 1849; &chi, 1939). Unlike the related family Tephritidae (Trypetidae) the Platystomatidae are of very slight economic importance so far as is known. However a species of Rivellia has been recorded as causing significant damage to a pasture legume in Queensland (Diatloff, 1965). Perhaps species of Duomyia play a role in pollination of some Eucalyptus species. 6 For the purposes of this work the limits of Australia have been interpreted in the political sense. Thus I include the six Australian states and the Northern Territory, but external territories of Australia are excluded. The Torres Strait Islands are included as part of the state of Queensland and Lord Howe Island is part of the state of New South Wales. Norfolk Island is excluded as an external territory. For practical reasons I do not use political boundaries for defining New Guinea, but apply the term to the main island of New Guinea together with only the most closely adjacent small islands. Thus defined New Guinea includes three zones: West New Guinea (West Irian); North East New Guinea (the Sepik, Highland, Madang, and Morobe Districts of the Trust Territory of New Guinea); and the Australian Territory of Papua. New Guinea material is only treated here when it is desirable to do so for comparative purposes. (B) Historical and Present State of Knowledge The first references to Australian species of the family Platystomatidae are by Guerin-Men4ville (1831-1838) and Macquart (1835 et seq.). Guerin included three Australian species in the. genus Platystoma, but one of these, Platystoma cincta Garin, was almost certainly collected from outside Australian limits. Macquart (18439 1847) established the genera Lamprogaster and Euprosopia on the basis of Australian species but his characterisations were superficial 7 in the extreme. In contrast to those of Gudrin, the specific descriptions given by Macquart are very brief with almost no characters other than those of coloration, and illustrations, when provided, are distorted and unclear. Walker (1849 et seq.) described many platystomatid species, a number of which were from Australia. His descriptions consist very largely of colour characters and there are no accompanying illustrations. Further, as Walker was notoriously inaccurate in his generic placings most subsequent authors have had difficulty in identifying his species. Thomson (1868) described two more Australian species. Loew (1873) placed most of the platystomatids known to him in the section Platystomina of the family Ortalidae and thus established a taxon roughly equivalent to the modern Platystomatidae. He also attempted a more precise and restricted definition of some of the genera. Froggatt (1907) and Tillyard (1926) referred to several Australian platystomatid species in their books on Australian insects. In accordance with the classification then widely current they placed the species in the family Ortalidae, though Froggatt also illustrated one species as a diopsid. Hendel (1914a, 1914b) gave the first comprehensive systematic review of the world Platystomatidae, including keys to genera and species and descriptions. He placed the family as a subfamily of the Muscidae of equal status with Ortalinae, Pyrgotinae, Pterocallinae, Ulidiin. .,and Richardiinae. In all subsequent publications he gave the 8 Platystomatidae family status. Although Hendel's primary sections of the Platystomatidae have not proved acceptable, his work is still to be regarded as authoritative and useful and his generic concepts remain with but little change. Unfortunately he did not designate type specimens for his new species, a fact which has caused difficulty as some of his "species" were composite. Complications in nomenclature have arisen from his publication of a list containing many now names (1914a) before giving formal descriptions of these new species (1914b). Enderlein (1924) described one new Australian species which was wrongly placed generically. He introduced a number of new generic names for segregates within the genera recognized by Hendel. These genera have almost all proved unacceptable to subsequent workers. Malloch (1928a et seq.) continued to build on the basis provided by Hendel. He described additional Australian species and began to place the differentiation of species on a more accurate basis. He gave a useful key to the Australian and New Guinean genera (1939a). Like Hendel, he did not examine the types of species described by Guerin, Macquart and Walker. As a result many of these species remain misinterpreted in literature to the present. Paramonov (1957) described several Australian species under the family name Ortalidae. Steyskal (1961) described 9 the genitalia of an Australian species.for the first time. Munro (1959) gave grounds for altering the name of a long established Australian genus. Diatloff (1965) provided the first information on larval biology of an Australian species. Up to the present approximately 65 valid species of Platystomatidae have been recorded as occurring in Australia. Possible synonymy among the recorded nominal species of Rivellia might reduce this number slightly. A review of the present state of knowledge of the Platystomatidae makes it apparent that few aspects of the biology of the family have yet been broached. The taxonomy of the group is much the best covered subject,