An Articulated Dragonfly (Insecta, Odonata) From The Upper Liassic Posidonia Shale Of Northern Switzerland

Abstract

An articulated dragonfly from the Lower Jurassic Posidonia Shale of northern Switzerland is described. The specimen is assigned to Liassogomphus brodiei (Buckman). This is the first description of an articulated member of the family Liassogomphidae, hitherto known from isolated wings only. Almost identical wings were previously described as Phthitogomphus angulatus (Handlirsch) and Palaeogomphus propinquus (Bode). The latter is now treated as synonymous with Liassogomphus brodiei, and the genus Palaeogomphus Handlirsch is therefore a junior synonym of Liassogomphus Cowley. The structures of the head, eyes, thorax, legs, and first segments of the abdomen confirm the state of the Liassogomphidae within the Anisoptera (or Pananisoptera) and point perhaps to a close relationship of the Liassogomphidae to the extant family Aeshnidae. This has already been stated previously based on wing venation patterns alone. The taphonomy of dragonflies in marine settings is briefly addressed. Only a combination of several exceptional circumstances led to the fossilization of this remarkable fossil. Key words: Odonata, Liassogomphidae, Jurassic, Posidonia Shale, insect taphonomy.