Hidden diversity in the Brazilian Atlantic rainforest: the discovery of Jurasaidae, a new beetle family (Coleoptera, Elateroidea) with neotenic females

Simone Policena Rosa,Katja Kramp,Robin Kundrata,Cleide Costa

doi:10.1038/s41598-020-58416-6

Abstract

Beetles are the most species-rich animal radiation and are among the historically most intensively studied insect groups. Consequently, the vast majority of their higher-level taxa had already been described about a century ago. In the 21st century, thus far, only three beetle families have been described de novo based on newly collected material. Here, we report the discovery of a completely new lineage of soft-bodied neotenic beetles from the Brazilian Atlantic rainforest, which is one of the most diverse and also most endangered biomes on the planet. We identified three species in two genera, which differ in morphology of all life stages and exhibit different degrees of neoteny in females. We provide a formal description of this lineage for which we propose the new family Jurasaidae. Molecular phylogeny recovered Jurasaidae within the basal grade in Elateroidea, sister to the well-sclerotized rare click beetles, Cerophytidae. This placement is supported by several larval characters including the modified mouthparts. The discovery of a new beetle family, which is due to the limited dispersal capability and cryptic lifestyle of its wingless females bound to long-term stable habitats, highlights the importance of the Brazilian Atlantic rainforest as a top priority area for nature conservation.

Highlights

Beetles are the most species-rich animal radiation and are among the historically most intensively studied insect groups
The first two larvae of the here described new elateroid lineage were collected in soil of a ravine along the main trail of the reserve (Fig. 1). Based on their bizzare morphology, including the remarkable mouthparts which resembled a beak, collectors were not able to assign the specimens to any known beetle family, it was obvious they belong to Elateroidea
All available evidence demonstrates the need to establish a new family within the Elateroidea for three new species in two new genera. Based on their divergent morphology (Figs. 2–5, S1–S12) and the results obtained from the molecular phylogeny (Figs. 6, S13), we describe here Jurasai digitusdei gen. et sp. nov., J. itajubense gen. et sp. nov. and Tujamita plenalatum gen. et sp. nov., for which we erect a new family Jurasaidae fam. nov

Summary

Introduction

Beetles are the most species-rich animal radiation and are among the historically most intensively studied insect groups. 400,000 species have been described, and many new ones are still frequently being discovered even in regions with historically high collecting activity[1] Because this group has been intensively studied since the age of early systematists, and most of the major higher-level taxa had already been described by about a century ago, discoveries of new beetle families are nowadays a rare occurrence. The first two larvae of the here described new elateroid lineage were collected in soil of a ravine along the main trail of the reserve (Fig. 1) Based on their bizzare morphology, including the remarkable mouthparts which resembled a beak, collectors were not able to assign the specimens to any known beetle family, it was obvious they belong to Elateroidea. All available evidence demonstrates the need to establish a new family within the Elateroidea for three new species in two new genera

Methods

Results

Conclusion