Uintatherium anceps

Overview

Uintatherium anceps is a mammal familiar for its head projections and long canine teeth. Middle Eocene specimens from Colorado are presented. Features of its large head can be compared alongside descriptions of the genus Uintatherium.^[1][2]

Key facts

Genus-level accounts describe six head projections, arranged in three pairs. The arrangement of several projections along a long skull stands out.^[2]

Time and place

Species-specific museum records report middle Eocene occurrences in present-day Colorado. The Eocene as a whole spans roughly 56–34 million years ago. Comparisons of head and limb structure can be added to records of locality and age.^[1][4]

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

Size, form and skeleton

Genus-level sources describe a long, flat skull with three pairs of projections and long canines. Historical descriptions also include a robust humerus and short femur and tibia. Different sources allow head and limb construction to be compared.^[2][3]

Uintatherium anceps had several pairs of projections on its large head. One skull specimen in a 2026 study measured approximately 83.6 cm from the nasal tip to the occipital crest. Measured using the scale in a photograph, this value gives a concrete sense of the enormous head’s size.^[5]

Habitat and reproduction

Do all the head projections have the same position and size? Examining the arrangement of three pairs helps distinguish the front and rear of the long skull. Canines and projections above the head are features of different regions.^[2]

Fossil discovery

An 1878 Princeton expedition report described bony cranial appendages and limb bones of Uintatherium. Species-level museum records report U. anceps from middle Eocene Colorado. Historical genus descriptions and species-specific specimen records contribute different information.^[3][1]

References

1. Fukui Prefectural Dinosaur Museum — Uintatherium anceps
2. Gwacheon National Science Museum — Head structure of Uintatherium
3. Osborn·Scott·Speir (1878) — Princeton expedition report
4. International Commission on Stratigraphy (2024) — Geological time chart
5. Mulcahy (2026) — Differences in skull size and shape in Uintatherium
6. Chudinov (1983) — Early therapsids and Estemmenosuchus

Research questions

How can historical descriptions and modern specimen catalogues be read together? One provides comparative head and limb morphology, while the other records species names, localities, and ages. Several kinds of records contribute to understanding one animal.^[1][3]

Observation

Examine the long, flat head, three pairs of projections, and long canines in turn. Then picture the limbs to compare the conspicuous head with other body regions.^[2][3]