The first Late Triassic Chinese triadophlebiomorphan (Insecta: Odonatoptera): biogeographic implications

Daran Zheng,Su-Chin Chang,He Wang,Haichun Zhang,Bo Wang,Edmund A Jarzembowski,André Nel

doi:10.1038/s41598-017-01710-7

Abstract

The clade Triadophlebiomorpha represents a morphological ‘link’ between the Paleozoic griffenflies (Meganisoptera) and the modern taxa. Nevertheless they are relatively poorly known in the body structures and paleobiogeography. The Triassic dragonfly is extremely rare in China with only one previously recorded. A new family, Sinotriadophlebiidae Zheng, Nel et Zhang fam. nov., for the genus and species Sinotriadophlebia lini Zheng, Nel et Zhang gen. et sp. nov., is described from the Upper Triassic Baijiantan Formation of Xinjiang, northwestern China. It is the second Chinese Triassic odonatopteran and the second largest Mesozoic representative of this superorder in China. The discovery provides new information for the clade Triadophlebiomorpha during the Late Triassic and expands its distribution and diversity in Asia. The find reflects a close relationship between the two Triassic entomofaunas from Kyrgyzstan and the Junggar Basin, and provides a Carnian age constraint on the lowermost part of the Baijiantan Formation.

Highlights

The clade Triadophlebiomorpha represents a morphological ‘link’ between the Paleozoic griffenflies (Meganisoptera) and the modern taxa
A further difference between Sinotriadophlebia and Triadotypus is that MP is simple in the latter but it has numerous posterior branches in the former
A new family is proposed based on the following combined differences: large size with wing length reaching up to 100 mm; distal part of ScP crossing N very obliquely with crossveins beneath it; CuA with numerous parallel posterior branches; RP and MAa fused into a long basal stem; Sn extremely oblique and very elongate, with several crossveins beneath it

Summary

Discussion

Sinotriadophlebia gen. nov. has a highly developed N with a kink in ScP, obvious nodal furrow, aligned Cr and Sn, and a typical odonatoid DC basally open but distally delimited by a characteristically oblique vein MAb between MA and MP. A new family is proposed based on the following combined differences: large size with wing length reaching up to 100 mm (within the Triadophlebiida, all species are less than 80 mm except Neritophlebia longa Pritykina, 1981 being 120–125 mm in length); distal part of ScP crossing N very obliquely with crossveins beneath it; CuA with numerous parallel posterior branches (a character present in Triadotypus, but more developed than in Sinotriadophlebia); RP and MAa fused into a long basal stem (a character present in Triadotypus, but not in all other Triadophlebiida); Sn extremely oblique and very elongate, with several crossveins beneath it (a character shared with the Neritophlebiinae). The relatively short distance between the Madygen fossil site and northwestern Xinjiang suggests a close relationship between the two insect faunas

Methods

Additional Information