Revision of the Ipsviciidae of the Late Triassic of Queensland (Hemiptera: Cicadomorpha: Scytinopteroidea).

Ipsvicia Tillyard, 1919, and Ipsviciopsis Tillyard, 1922, in Tillyard's new family, Ipsviciidae, were two of the most impressive insects from the Denmark Hill locality of the Late Triassic (Norian) Blackstone Formation, Ipswich Coal Measures, south-eastern Queensland. Substantial new material, including several fragmentary body specimens, from the Dinmore locality in the same formation, has enabled a revision of the two genera, with the following results: Ipsvicia jonesi Tillyard, 1919 (= Ipsvicia maculata Tillyard, 1919, syn. nov., = Ipsvicia acutipennis Tillyard, 1919, syn. nov.), Ipsviciopsis elegans Tillyard, 1922 (= Ipsviciopsis magna Tillyard, 1922, syn. nov.). The tegmen of Ipsviciopsis is distinguished from that of Ipsvicia on its narrower shape and less convex costal margin, simpler surface sculpture, longer basal cell, sinuous R, only slightly angulate CuA, and sinuous base of 1A. The tegmina of both I. jonesi and I. elegans are noteworthy for their variability in apical venation and shape of the apex, with no two specimens quite the same. The tegmen of I. jonesi has extraordinary surface sculpture comprising patches of fine tubercles set in a coarser tuberculate/punctate groundmass, the patches extremely variable in shape and pattern, again with no two specimens the same. A new diagnosis of the Ipsviciidae has identified the unique form of the distal portion of Sc (dSc-a long groove running along the costal space and crossed by many costal veinlets), the complex and highly variable apical venation, and the simple CuA, as the most distinctive characters. Analysis of all previous taxa which have been referred to the Ipsviciidae restricts the family to the Middle to Late Triassic, with records from Australia, China, France, Germany, Japan and Kyrgyzstan, and with one Early Jurassic record from Kyrgyzstan. Ipsvicia langenbergensis Barth, Ansorge et Brauckmann, 2011, from the Late Triassic of Germany meets the diagnosis of Ipsviciopsis and is transferred as Ipsviciopsis langenbergensis (Barth, Ansorge et Brauckmann, 2011) comb. nov. All previous Permian records of the family have now been transferred to other families of the Scyctinopteroidea, and there are also numerous additional unconfirmed Triassic records. The new body specimens of both Ipsvicia and Ipsviciopsis show that the ipsviciids where robust hemipterans with tough, coriaceous, fairly flatly-folded tegmina, with a large, shield-like, highly sculptured pronotum covering all but the mesoscutellum, and apparently much of the head. The body form is not dissimilar to ground-dwelling cockroaches, or more especially some ground-dwelling moist environment Heteroptera, such as the nepomorph family Gelastocoridae. This body form, as well as their frequent occurrence among the rich Dicroidium-dominant flood plain and swamp flora of the Dinmore locality, where they represent nearly 20% of the preserved insect fauna (cockroaches represent 25%), suggest that the ipsviciids were ground-dwelling insects of moisture-rich floral environments.