Eocuculus cherpinae

Overview

Eocuculus cherpinae was a small fossil bird preserving a partial skeleton and feather impressions. It is known from material at Florissant in present-day Colorado, United States. Postcranial bones and feathers together convey an ancient bird’s form.^[1]

Key facts

Two fossil numbers do not necessarily mean two birds. DM10682 and DM10683 are the slab and counterslab containing one fossil. Traces left on both sides when the rock split connect as evidence of one animal.^[1]

Time and place

It was a fossil bird from around the Eocene–Oligocene transition, roughly 34 million years ago. It is known from Florissant in present-day Colorado, United States. Bones and feathers in ancient layers allow comparisons among regional birds.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

A small, robust skeleton and short tarsometatarsus are described. Traces of feathers also remain on the body. Small leg bones can be compared with the feather covering.^[1]

Eocuculus cherpinae was a small Cenozoic bird. Its type specimen from Florissant in present-day Colorado, United States, had a left humerus 2.7 cm long. Although the head is absent, several bones and feather impressions survive together, allowing its wings and legs to be examined in connection.^[3]

Habitat and reproduction

A 1999 study interpreted it as arboreal from its short tarsometatarsus and small, robust skeleton. This compares leg proportions and postcranial bones with other birds. Including the feathered body allows its way of life to be explored through several regions.^[1][2]

Fossil discovery

The fossil collected by Colette Cherpin and Jeffrey Carpenter was donated to Denver’s natural history museum in 1993. Chandler introduced Eocuculus in 1999 by studying the slab and counterslab of one individual. Collection, donation, and comparative research connected the small bird’s story.^[1]

References

1. Chandler1999 — Eocuculus, a fossil bird from Florissant
2. 2022 study — Comparing the classification of Eocene birds
3. Chandler (1999) — Fossil birds of Florissant and description of a new Eocuculus species
4. 2015–2016 study — The postcranial skeleton and new specimens of Gansus

Research questions

Which relatives does the body of a small bird indicate? Following initial comparisons with cuckoos, studies continued to compare its skeleton with other bird material. Leg bones and body features together help reveal an ancient bird’s relationships.^[1][2]

Observation

Move your gaze from the small trunk to the short bones of the lower leg. Thinking of feather impressions together with bone positions reveals the story of one bird divided between two rock surfaces.^[1]