Two new damselflies from the Eocene Green River Formation (Odonata, Zygoptera, Dysagrionidae, Thaumatoneuridae)

André Nel ¹

⁰Institut de Systématique; Evolution; Biodiversité (ISYEB); Muséum national d'Histoire naturelle; CNRS; Sorbonne Université; EPHE; Université des Antilles; CP 50; 57 rue Cuvier; 75005 Paris; France. anel@mnhn.fr.

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December 8, 2024

View abstract on PubMed

Summary

Two new fossil damselfly species, Gusagrion coloratum and Petrolestes inexpectatus, were discovered in Eocene Eocene Green River Formation deposits. This finding highlights the significant diversity of ancient large damselflies, suggesting major Eocene-Oligocene Odonata fauna shifts.

Area Of Science

Paleontology
Entomology
Fossil insects

Background

The Eocene Green River Formation preserves a rich fossil record of ancient life.
Odonata (damselflies and dragonflies) diversity provides insights into past ecosystems.

Purpose Of The Study

To describe two new damselfly taxa from the Eocene Green River Formation.
To assess the diversity and composition of Eocene Odonata fauna.

Main Methods

Description of new taxa based on isolated wing fossils.
Comparative analysis of fossil wing morphology with extant and extinct Odonata.

Main Results

Discovery and description of Gusagrion coloratum (new genus and species) and Petrolestes inexpectatus (new species).
These new taxa belong to the extinct Eodysagrioninae and Dysagrionidae families.
The described species indicate a high diversity of large-bodied damselflies in the Eocene, surpassing smaller damselflies and large dragonflies (Anisoptera).

Conclusions

The Eocene Odonata fauna of the Green River Formation was characterized by a notable diversity of large damselflies.
Significant changes in Odonata faunal composition likely occurred between the Eocene and Oligocene epochs.