Work

New fossil species of Trechinae (Coleoptera: Carabidae) from mid-Cretaceous French amber helps refining the age of the subfamily and its tribes under total-evidence dating

Year: 2026

Type: article

Abstract: The oldest fossil of Trechinae Bonelli, 1810, †Cydonius musei gen. et sp. nov., is described from the Charentese French amber (ca. 100 million years ago). Using total-evidence dating, which integrates morphological and molecular data, as well as fossils as tips, we tested its phylogenetic placement among Trechinae and obtained divergence time estimates for the subfamily and their tribes. Our results suggest a crown age of Trechinae around 137.6 million years ago and of Trechitae around 130 million years ago. Moreover, our total-evidence analyses consistently place †C. musei gen. et sp. nov. as a sister lineage of Anillini, with a divergence estimated at ∼104 million years ago. Morphologically close to the euedaphic tribe Anillini Jeannel, 1937, †C. musei gen. et sp. nov. possesses hind wings and eyes, unlike extant representatives of this tribe, which, together with its preservation in putatively aerial amber, suggest an epigean rather than euedaphic lifestyle for this fossil species. Its phylogenetic position relative to Anillini is discussed in the frame of character evolution. Furthermore, we also discuss the age of Trechinae and their tribes within a broader evolutionary framework. The discovery of †C. musei gen. et sp. nov. bridges an important temporal and ecological gap in Trechinae evolutionary history and opens new perspectives on the evolution of the subfamily.

Source: Insect Systematics and Diversity

DOI: 10.1093/isd/ixag028

Authors: Jules Ferreira, Éric Quéinnec, Laura Pajot, Vincent Perrichot, David Peris