The first fossil salmonfly (Insecta: Plecoptera: Pteronarcyidae), back to the Middle Jurassic

Abstract

BackgroundThe fossil record of Plecoptera (stoneflies) is considered relatively complete, with stem-groups of each of the three major lineages, viz. Antarctoperlaria, Euholognatha and Systellognatha (and some of their families) represented in the Mesozoic. However, the family Pteronarcyidae (the salmonflies; including two genera, Pteronarcys and Pteronarcella) has no fossil record to date, and the family has been suggested to have diverged recently.ResultsIn this paper, we report on a set of specimens belonging to a new fossil species of stonefly, discovered from the Middle Jurassic Daohugou locality (China). Our comparative analysis of wing venation and body characters demonstrates that the new species belongs to the Pteronarcyidae, and is more closely related to Pteronarcys than to Pteronarcella. However, it differs from all known species of the former genus. It is therefore assigned to a new genus and named Pteroliriope sinitshenkovae gen. et sp. nov. under the traditional nomenclatural procedure. The cladotypic nomenclatural procedure is also employed, with the resulting combination Pteroliriope nec Pteronarcys sinitshenkovae sp. nov. ConclusionsThe first discovery of a fossil member of the Pteronarcyidae demonstrates that the corresponding lineage is not a very recent offshoot but was already present ca. 165 million years ago. This discovery concurs with the view that divergence of most stonefly families took place very early, probably in the Triassic, or even in the Permian. This contribution demonstrates the need for (re-)investigations of the systematics of fossil stoneflies to refine divergence date estimates for Plecoptera lineages.

‘Rolling’ stoneflies (Insecta: Plecoptera) from mid-Cretaceous Burmese amber

“…Therefore, based on the shape of labium, a relationship to the other systellognathan superfamily, Pteronarcyoidea, would seem more probable. However, neither Petroperla gen. nov. nor Lapisperla gen. nov. any of the wing venation characters known to represent traits of individual Pteronarcyoidea lineages ( Cui et al, 2016 ), which are numerous crossveins between M and CuA in distal half of wing; AA2 with more than three branches; and M with more than two branches. Moreover, Petroperlidae feature several wing venation characters not present in Systellognatha.…”

A new stonefly species (Plecoptera: Perlodidae) from Eocene Baltic amber and questions on the wing venation potential for species diagnostic of fossil Plecoptera

“…5). This suggests that our specimen may be better preserved on this part of the body than those figured in Cui et al (2016), since they all have a poorly preserved quadrate pronotum.…”

“…Additionally, our specimen differs from all other species of Isoperla by its temporal range (Eocene vs. extant). 5, 6) of the Middle Jurassic Pteroliriope sinitshenkovae Cui, Béthoux, Kondratieff, Shih & Ren, 2016. As illustrated in Cui et al (2016) the wing venation is highly variable in this taxon; even the main veins (viz. MA, MP, CuA) are configured differently depending on the observed specimens.…”

Peer Review #2 of "‘Rolling’ stoneflies (Insecta: Plecoptera) from mid-Cretaceous Burmese amber (v0.1)"

“…Therefore, based on the shape of labium, a relationship to the other systellognathan superfamily, Pteronarcyoidea, would seem more probable. However, neither Petroperla nor Lapisperla possess any of the wing venation characters known to represent traits of individual Pteronarcyoidea lineages (Cui et al, 2016), which are numerous crossveins between M and CuA in distal half of wing; AA2 with more than three branches; and M with more than two branches. Moreover, Petroperlidae feature several wing venation characters not present in Systellognatha.…”