Eoconodon coryphaeus

Overview

Eoconodon coryphaeus introduces mammals from after the dinosaur mass extinction. Its skulls, teeth, and a partial humerus are studied. It helps trace Paleocene changes as ecosystems filled again.^[1][3]

Key facts

What if fossil hunters looked for rounded stones instead of bone fragments? At Corral Bluffs, Colorado, skulls inside hard concretions marked a turning point in discovery. Eoconodon skulls from the area were also used in comparisons of early mammals.^[1][3]

Time and place

This North American mammal lived in the early Paleocene, roughly 66–63 million years ago. Teeth have been reported from the San Juan Basin in present-day New Mexico, USA. Well-preserved skulls were also discovered at Corral Bluffs in Colorado’s Denver Basin.^[2][1]

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

Size, form and skeleton

A 2024 study mentions two nearly complete skulls. AMNH764, part of a right humerus, was also used for comparison. Different clues from the head and arm are brought together to explore the bodies of early mammals.^[1]

A 2019 study estimated a body mass of approximately 47 kg for Eoconodon coryphaeus. Researchers described it as one of the large mammals appearing around 700,000 years after the dinosaur mass extinction, showing that mammals grew larger as forests recovered.^[10]

Habitat and reproduction

The ancient mammal group to which it belongs is known through studies examining dental features suited to carnivory. Comparisons with the skulls and arm bones of relatives help explore dietary and locomotor diversity. They raise questions about the ecological roles mammals occupied after the mass extinction.^[1]

Fossil discovery

A 2011 study compared Eoconodon teeth and occurrences across regions. New discoveries at Corral Bluffs added skull material. Its skulls and humerus were also used in a 2024 skeletal study of Triisodon.^[2][1][3]

References

1. Toosey et al.2024 — Skeletal comparisons of Triisodon and early mammals
2. Clemens2011 — Teeth and Paleocene distribution of Eoconodon
3. Denver Museum of Nature & Science — The story of mammalian recovery
4. Lucas & Kondrashov (2004) · Taxonomic Revision of the Genus Ectoconus (Mammalia, Periptychidae) from the Paleocene of the Western United States · New Mexico Museum of Natural History and Science Bulletin 26
5. AMNH — Paleocene environments and Ectoconus
6. Science in the Classroom — Exceptional record of biotic recovery after the K–Pg mass extinction
7. Clemens2011 — Teeth and Paleocene distribution of Eoconodon
8. Toosey et al.2024 — Skeletal comparisons of Triisodon and early mammals
9. Denver Museum of Nature & Science — The story of mammalian recovery
10. Lyson et al. (2019) — Recovery of ecosystems and mammals after the mass extinction

Research questions

How can one animal’s bones help explain another? Joints, muscle attachments, and tooth shapes can be compared side by side. Interconnected fossil evidence gradually reveals the evolution and lives of early mammals.^[1]

Observation

Move your gaze from the head and jaws to the humerus. Parts used in feeding and parts used in movement together tell the story of early mammals.^[1][2][3]