5.1" Brontothere Fossil Knee Bone Eocene Age Badlands S Dakota Titanothere COA

Location: White River Badlands, South Dakota

Weight: 2 Pounds 9 Ounces

Dimensions: 5.9 Inches Long, 3.9 Inches Wide, 3.2 Inches Thick (Matrix)

Eocene Age, 56 to 33.9 million years Old.

Comes with a Certificate of Authenticity.

The item pictured is the one you will receive. 

Brontothere is an ancient mammal that roamed the area of Badlands National Park about 56-33.9 million years ago. Badlands brontotheres are also known as Megacerops coloradensis in scientific literature. Sometimes called “titanothere,” its name means “thunder beast,” referring to how a traveling herd of massive brontotheres may have sounded long ago, thundering through ancient environments.

Brontotheres from the Badlands grew to remarkable sizes, reaching about 8 feet in height and 16 feet in length, roughly the size of a modern large rhinoceros or small elephant. However, early Eocene brontotheres were only dog-sized. Over the course of 20 million years, they gradually evolved and diversified, eventually achieving the massive proportions seen in the late Eocene fossils of the Badlands.

Brontotheres are most recognized for the blunt paired horns that extended from their noses. Over time, these horns grew from small nubs into massive structures, sometimes exceeding 3.3 feet (1 meter) in length in Badlands specimens. Horn size typically varies by sex, with males sporting larger horns than females. While these horns may bring modern rhinos to mind, brontotheres are only distant relatives. True ancestors of today’s rhinoceroses, such as Subhyracodon, also appear in the Badlands fossil record, representing the evolutionary lineage of modern rhinos.