A unique, large-sized stem Odonata (Insecta) found in the early Pennsylvanian of New Brunswick (Canada)

Abstract

Abstract. A stem relative of dragon- and damselflies, Brunellopteron norradi Béthoux, Deregnaucourt and Norrad gen. et sp. nov., is documented based on a specimen found at Robertson Point (Grand Lake, New Brunswick, Canada; Sunbury Creek Formation; early Moscovian, Pennsylvanian) and preserving the basal half of a hindwing. A comparative analysis of the evolution of wing venation in early odonates demonstrates that it belongs to a still poorly documented subset of species. Specifically, it displays a MP + CuA fusion, a CuA + CuP fusion, and a CuP + AA fusion, but it lacks the “extended” MP + Cu / CuA fusion and the “extended” (CuP / CuA + CuP) + AA fusion, the occurrence of which is typical of most Odonata, including Meganeura-like species. The occurrence of intercalary veins suggests that its closest relative might be Gallotypus oudardi Nel, Garrouste and Roques, 2008, from the Moscovian of northern France.

Little bits of dragonfly history repeating exemplified by a new Pennsylvanian family

“…Such cross-vein is present in Protanisoptera (white star in electronic supplementary material, figure S1 f ), making this interpretation more parsimonious. It implies that CuA and CuP diverge fused together from MP + Cu(+AA) (as opposed to successively, as in most Meganisoptera and in Protanisoptera), but a similar configuration is known to have occurred in some Meganisoptera [ 8 ]. Overall, these aspects of wing venation homologies have very limited implications on the extent of the CuA and AA areas.…”

“…Indeed, this organ underwent intense transformations during the 320 Myr of the recorded evolution of the group [1][2][3], a phenomenon which can be related with flight performance, a key aspect in these insects' ecology, such as foraging and mating [4]. Actually, morphological transformations were so strong that it made it challenging to relate odonate wing venation with that of other insects until early representatives, displaying a yet generalized pattern, were discovered [5], putting an end to decades of debate [1,[6][7][8].…”

New light shed on Triadophlebiomorpha wing morphology and systematics (Insecta: Odonata)

“…However, the possibility that this configuration evolved from a simple RP3+4 complemented by numerous posterior I-and I+, or a RP3+4 posteriorly pectinate and a complementary set of I+, is to be discussed. A relevant analogue is the organisation of the venation in the MA-MP area in large-sized meganisopterans (see Zessin 1983;Nel et al 2009;Li et al 2013;Béthoux et al 2021). Here the vein-like structure immediately anterior to MP is convex (as is MA) and is usually branched before its mid-length; while the more distal part of the MA-MP area is filled with a regular alternation of convex and concave veins, generally simple.…”

The earliest beetle †Coleopsis archaica (Insecta: Coleo­ptera) – morphological re-evaluation using Reflectance Transformation Imaging (RTI) and phylogenetic assessment

“…In palaeontology RTI provides a valuable alternative to competing techniques such as µCT scanning or structure from motion techniques, such as photogrammetry or 3D laser scanning, especially for fossils with a low relief that are located on flat surfaces (Hammer et al 2002;Jäger et al 2018;Kenchington et al 2018). In palaeoentomology RTI turned out as a suitable method for imaging strongly compressed fossils, especially insect wings (Béthoux et al 2016(Béthoux et al , 2021Cui et al 2018). While it is possible to produce RTI models of very small objects, the constraints of macro-photography regarding the depth of field and the field of view limit the application of a conventional RTI procedure (Cosentino 2013;Hughes-Hallett et al 2021).…”

“…Inkscape (GPL v.3.0 license) was used to produce the drawings and to arrange the figure plates. The circular graphic legends for the normal map and height map images (depicting the reference sphere) were made following (Béthoux et al 2021;Cui et al 2022).…”