Transitional fossil earwigs - a missing link in Dermaptera evolution

Jingxia Zhao,Yunyun Zhao,Chungkun Shih,Yongjie Wang,Dong Ren

doi:10.1186/1471-2148-10-344

Abstract

BackgroundThe Dermaptera belongs to a group of winged insects of uncertain relationship within Polyneoptera, which has expanded anal region and adds numerous anal veins in the hind wing. Evolutional history and origin of Dermaptera have been in contention.ResultsIn this paper, we report two new fossil earwigs in a new family of Bellodermatidae fam. nov. The fossils were collected from the Jiulongshan Formation (Middle Jurassic) in Inner Mongolia, northeast China. This new family, characterized by an unexpected combination of primitive and derived characters, is bridging the missing link between suborders of Archidermaptera and Eodermaptera. Phylogenetic analyses support the new family to be a new clade at the base of previously defined Eodermaptera and to be a stem group of (Eodermaptera+Neodermaptera).ConclusionEvolutional history and origin of Dermaptera have been in contention, with dramatically different viewpoints by contemporary authors. It is suggested that the oldest Dermaptera might possibly be traced back to the Late Triassic-Early Jurassic and they had divided into Archidermaptera and (Eodermaptera+Neodermaptera) in the Middle Jurassic.

Highlights

The Dermaptera belongs to a group of winged insects of uncertain relationship within Polyneoptera, which has expanded anal region and adds numerous anal veins in the hind wing
The suborder Eodermaptera is well assembled in the analyses that is only concerned for the fossil taxa, supported by one synapomorphic character: fusion of 8th and 9th abdominal tergites in females (Cha. 15: 1) (Figure 3a)
In the analysis including the extant representatives, Eodermaptera grouping with Neodermaptera constitute a monophyly, sharing with Cha. 15 (Figure 3c). It resulted in some different cladograms, our new family is firmly assigned to the Eodermaptera or (Eodermaptera +Neodermaptera), representing a stem-group of the clade

Summary

Introduction

Evolutional history and origin of Dermaptera have been in contention. The Dermaptera belongs to a group of winged insects of uncertain relationship within Polyneoptera, which has expanded anal region and adds numerous anal veins in the hind wing [1]. Earwigs are very scarce in the insect fossil record. Even with subsequent addition of 10 species, the fossil record of the Dermaptera stands at 83 species [3,4]. Evolutional history and origin of Dermaptera have been in contention, especially for the fossil earwigs

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Conclusion