Most Paleozoic Protorthoptera are ancestral hemipteroids: major wing braces as clues to a new phylogeny of Neoptera (Insecta)

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Abstract
The enigmatic and artificial Protorthoptera is the largest Paleozoic order of Neoptera. Typical hemipteroid head characters (inflated clypeus, styletal mouthparts) are here reported for "Protorthoptera" fossils and linked with the basic venational braces of hemipteroid wings. The "order" is recognized as being mostly composed of extremely primitive hemipteroids. Two new Late Carboniferous gerarid wings are described: Osnogerarus trecwithiensis n.gen., n.sp. from the Westphalian D of Osnabrück, Germany, and Cantabrala gandli n.gen., n.sp. from the Lower Stephanian (Cantabrian) of the Cantabrian Mountains, northwestern Spain. Several ground-plan characters of hemipteroids are described: head with visible segmentation; polyramous thoracic legs bearing exites and with trochanter not fused to prefemur; ovipositor with cutting ridges; the medial wing vein is shown as not the complete media (= M), but only the media posterior (= MP); the arculus is diagnosed as a cross-vein turned into an important brace; two radial sectors (RA and RP) originate separately from the radial basivenale; and the anal brace is formed by AA1. The hemipteroid stem-assemblage comprised (i) the gerarid line (extinct) with a long MP–CuA fusion replacing the arculus (derived) and with a repeatedly forked CuP (primitive), and (ii) the paoliid line with an arculus (a convex mp–cua cross-vein) (primitive) and a simple CuP (derived). The paoliids are the probable ancestors of modern hemipteroids. The Hemiptera (Sternorrhycha + Auchenorrhyncha + Coleorrhyncha + Heteroptera) lost the ScA + vein to a V-shaped notch or a flexion line (synapomorphy). Geraridae, Paleozoic and Recent Insecta, and all Arthropoda have demonstrably polyramous legs in the ground plan. Use of the taxon "Uniramia" is erroneous in every aspect. A new method using major venational braces is offered to define the wings of all higher neopteran taxa and to resolve the uncertain relationships between some modern orders. Polyneoptera (plecopteroids + orthopteroids + blattoids) is a polyphyletic taxon, and should be abandoned. Blattoids are not directly related to orthopteroids, but are the sister-group of hemipteroids + endopterygotes. An updated basic phylogenetic scheme of Neoptera proposed here comprises the following clades: (Pleconeoptera (Orthoneoptera (Blattoneoptera (Hemineoptera + Endoneoptera)))).