Unlocking the mystery of the mid-Cretaceous Mysteriomorphidae (Coleoptera: Elateroidea) and modalities in transiting from gymnosperms to angiosperms

David Peris,Bastian Mähler,Conrad C Labandeira,Jes Rust,Robin Kundrata,Xavier Delclòs,Michael A Ivie

doi:10.1038/s41598-020-73724-7

Abstract

The monospecific family Mysteriomorphidae was recently described based on two fossil specimens from the Late Cretaceous Kachin amber of northern Myanmar. The family was placed in Elateriformia incertae sedis without a clear list of characters that define it either in Elateroidea or in Byrrhoidea. We report here four additional adult specimens of the same lineage, one of which was described using a successful reconstruction from a CT-scan analysis to better observe some characters. The new specimens enabled us to considerably improve the diagnosis of Mysteriomorphidae. The family is definitively placed in Elateroidea, and we hypothesize its close relationship with Elateridae. Similarly, there are other fossil families of beetles that are exclusively described from Cretaceous ambers. These lineages may have been evolutionarily replaced by the ecological revolution launched by angiosperms that introduced new co-associations with taxa. These data indicate a macroevolutionary pattern of replacement that could be extended to other insect groups.

Highlights

The monospecific family Mysteriomorphidae was recently described based on two fossil specimens from the Late Cretaceous Kachin amber of northern Myanmar
The new taxon was originally classified as Elateriformia incertae sedis, and the genus and family name were designated based on a unique combination of characters that are present variously in different lineages of Elateroidea and B yrrhoidea[21]
Mysteriomorphidae were placed as Elateriformia incertae sedis, and the authors discussed their affinities either to Byrrhoidea or to Elateroidea[21]

Summary

Introduction

Among the slightly more than 80 beetle families with at least one representative described from Cretaceous ambers[8], six are solely fossil lineages: Elodophthalmidae and Tetrameropseidae from Lebanese amber and Apotomouridae, Mesophyletidae, Mysteriomorphidae, and Passalopalpidae from Kachin amber (see references and details in[8]) These lineages represent a relatively high proportion of taxa for the low extinction rate over the long evolutionary history of Coleoptera[9,10,11]. The generally cited decrease in diversity, may have been responsible for a relatively high number of beetle families described in the amber record from the Cretaceous that currently do not exist One of these fossil families, Mysteriomorphidae, recently was established based on two specimens described as Mysteriomorphus pelevini Alekseev and Ellenberger, 2019. The morphology of taxa within this lineage should be treated carefully when establishing a classification, attributable to the independent evolutionary origins of the soft-body condition, neoteny and other confounding traits within the encompassing c lade[24,25,26,27]

Methods

Discussion

Conclusion