Mesevania swinhoei fósil en ámbar de Burma
English: Title: Bulletin of the Natural History Museum Geology Identifier: bulletinofnatura561natu (find matches) Year: 2000 (2000s) Authors: Natural History Museum (London) Subjects: Publisher: Andover : Intercept Contributing Library: Natural History Museum Library, London Digitizing Sponsor: Natural History Museum Library, London View Book Page: Book Viewer About This Book: Catalog Entry View All Images: All Images From Book Click here to view book online to see this illustration in context in a browseable online version of this book. Text Appearing Before Image: 54 H.H. BASIBUYUK ET AL. species occur in the tropics. As the classification of the group is still largely based on Kieffer (1912), the validity of many genera is questionable (Huben, 1995). Until recently, the known extinct species of the family were attributed to the extant genera Evania (Burmeister, 1831;Brues, 1933) and Brachygaster (Buschke, 1886), but two new genera from Late Cretaceous, New Jersey amber have recently been described (Basibuyuk et al, in press). Another Mesozoic fossil, Praevania Rasnitsyn, possibly also belongs to the Evaniidae, and is known from the middle Lower Cretaceous of Mongolia (Rasnitsyn, 1991). Here, we describe a distinctive new species of evaniid belonging to a new genus from Burmese amber. The fossil described has a considerable part of the head distorted while the legs, meso- and metasoma are covered with organic debris. Nevertheless those ob- servable characters, notably the modified hind tibia, forewing venation and antennal morphology, are sufficient to distinguish this insect from all other known evaniid genera. It has several forewing and antennal features that are plesiomorphic for the whole of the Evanioidea, as well as several characters that are synapomorphic for the Evaniidae. This fossil, together with the two new genera described from New Jersey amber, permits us to suggest possible transitions leading to modern evaniids. The material studied is in the Department of Palaeontology, The Natural History Museum, London, U.K. Morphological terminol- ogy largely follows Gauld & Bolton (1988). Family EVANIIDAE Latreille, 1802 Genus MESEVANIA Basibuyuk & Rasnitsyn, gen. nov. Type species. Mesevania swinhoei Basibuyuk & Rasnitsyn, sp. nov., here designated. NAME. Combining meso, meaning middle, with Evania, in refer- ence to this being a primitive Mesozoic evaniid. The name is feminine. DIAGNOSIS. Female. Size small (body length about 3 mm). Mesosoma and metasoma not heavily sclerotized (Figs 1, 2). An- tenna with more than 15 segments, clavate, not elbowed; antennal insertion slightly above the mid point of eye, inserting on slight shelf; scape and pedicel short, first flagellar segment not much longer than any of the following six segments (Fig. 3a). Pronotum short medi- ally. Petiole joining propodeum at a point much closer to metanotum than to hind coxa (Fig. 2). Forewing venation complete, with 10 enclosed cells (Fig. 3c); veins 2m-cu and 3rs-m present, veins 2rs-m and 3rs-m bordering an hexagonal 3rd submarginal cell; vein M & Rs (basal vein) straight, not angled at junction of veins M and Rs, meeting vein R well before pterostigma, meeting vein M+Cu much closer to pterostigma than to wing base; vein lm-cu meeting 2nd submarginal cell well beyond its base; vein M angled at junction with vein lm-cu forming a pentagonal 2nd submarginal cell; vein Rs angled at junction with 3rd submarginal cell, otherwise straight, reaching the anterior margin of wing (Fig. 3c). Hindwing venation presumably reduced, only indications of veins R and M+Cu can be seen, with few (4 or 5) distal hamuli. Fore tibia enlarged apically with outer face compressed (but this may be due to deformation of the leg) (Fig. 3a). Hind tibia highly modified; expanded and compressed apically, its inner face with a finely striate, mirror-like structure. Tarsi of all legs 5-segmented (Fig. 3b). Metasoma short, longer than petiole, ovate. Ovipositor exserted (Fig. 2). Remarks. The peculiar modification of the hind tibia is the single most prominent character of the new genus (Fig. 3b). Whether the swollen tibia is a synapomorphy of Mesevania, or a symplesiomorphy, is difficult to say (see Discussion below). In addition to the tibial swelling, several other characters of Mesevania are also unusual for the Evaniidae, notably the very complete forewing venation and the multi-segmented antenna with a short scape. Mesevania differs from the rest of the Evaniidae (including the two new genera from New Jersey amber; Basibuyuk et al, in press) in having the forewing with 10 enclosed cells, veins 2m-cu and 3rs-m being present (see Figs 4a, c-e) and in having the antenna without an elbow, multi-segmented, and with a short scape. A relatively complete forewing venation, particularly the presence of veins 2m-cu and 3rs-m, is the ground plan character state for Evanioidea, as represented by the Praeaulacidae and Aulacidae (Figs 4f-h). Praevania sculpturata Text Appearing After Image: Fig. 1 Mesevania swinhoei new species, holotype, In.20192, Burmese amber. Forewing length 2.4mm. Fig. 2 Mesevania swinhoei new species, holotype (Scale: 0.5 mm) In.20192, Burmese amber. Lateral aspect. 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