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

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.

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

“…Composition . — The super-families Triadophlebioidea (including the families Triadophlebiidae, Mitophlebiidae and Sinotriadophlebiidae; and the genus Nototriadophlebia n. gen. newly described herein, whose familial affinities remain uncertain) and Zygophlebioidea (including the families Zygophlebiidae and Xamenophlebiidae); and the genera Reisia Handlirsch, 1912, Piroutetia Meunier, 1907 and Triassologus Riek, 1976 as delimited herein, of uncertain super-familial affinities (see Pritykina 1981; Bechly 1996; Nel et al 2001; Zheng et al 2017b).…”

“…However, new material described below reveals that it is not the case, RP and MA being very close but distinct. Also, according to the reconstruction given by Zheng et al (2017b) of Sinotriadophlebia lini (fig. 2), a long RP+MA stem occurs in this species, but this is contradicted by detailed photographs published by these authors (fig.…”

“…How the main taxa of Triadophlebiomorpha relate requires a specific discussion in the light of our new data on several key taxa. Nel et al (2001; and see Zheng et al 2017b) excluded the Triadotypidae Grauvogel & Laurentiaux, 1952 (the only family composing the taxon Triadotypomorpha Bechly, 1996) from the Discoidalia, while most other Triassic taxa displaying a seemingly branched RP3+4 were assigned to the Triadophlebiomorpha, within Discoidalia. This proposal essentially rested on the presumed lack of a pons in representatives of the Triadotypidae (Nel et al 2001; and see Grauvogel & Laurentiaux 1952).…”

“…Besides the rare Panodonata, the taxon including crown-Odonata and represented by mid-sized species at the time (Bechly 1997; Nel et al 2002; Pritykina 1981; Tierney et al 2020), the gracile, damselfly-like type was represented by the Archizygoptera (Bechly 1997; Deregnaucourt et al 2021b; Felker 2022; Nel et al 2005; Pritykina 1981). Besides these two taxa, the Triadophlebiomorpha, a group almost exclusively Triassic, included the most large-sized odonatans of the time and evolved a number of peculiar structures, such as a very large area between RP3+4 and MA, a very long petiole, and a number of distinctive vein fusions (Pritykina 1981; Nel et al 2001; Béthoux et al 2009; Béthoux & Beattie 2010; Deregnaucourt et al 2017, 2021a; Zheng et al 2017a, b; Jouault et al 2023). However, resulting from the combination of a large size and relative rarity (as expected from presumed top predators), most Triadophlebiomorpha species are known from few and/or incomplete wings.…”

First record of hawker dragonflies from Eocene Baltic amber (Odonata: Anisoptera: Gomphaeschnidae)

“…While small insects (predominantly Diptera and Hymenoptera) are abundant and completely preserved as inclusions in Baltic amber, large insects are much rarer and usually fragmentary, because they could either escape the sticky resin or where eaten by scavenging insects before completely embedded. Odonata are especially rare in Baltic amber (Bechly 1996a(Bechly , 1998, while they are very diverse and surprisingly frequent in Mid-Cretaceous Burmese amber (Zheng et al 2016a(Zheng et al ,b, 2017. Anisoptera are even more elusive, with only four specimens yet been reported from Baltic amber (Bechly 1998;Bechly & Wichard 2008), and only one more from Paris Basin amber (Fleck et al 2000), and three more from Burmese amber (Schädel & Bechly 2016;Zheng et al 2016Zheng et al , 2017.…”