Perchoerus Jaw Section-South Dakota

Identification: Perchoerus sp. Lower Left Mandible (Jaw)

Age: Oligocene

Geology: Brule formation

Locality: South Dakota

 This jaw section includes 2 molars. The larger molar had erupted shortly before death, which tells us it was an adult but not old when this animal passed. No repairs or restorations. 

Perchoerus

Perchoerus is an extinct genus of small suiform artiodactyls from the Eocene–Oligocene of North America, traditionally treated as an early peccary but now often regarded as a basal suine outside both modern peccaries and true pigs. Three species are recognized, ranging from the tiny P. minor, about house‑cat sized, to the larger P. probus, which approached living peccaries in body size and is known from more complete cranial and dental material. Stable carbon isotope data from P. probus teeth suggest it inhabited dense, riparian environments.

Brule formation

The Brule Formation is an Oligocene unit (about 34–30 million years old) within the White River Group, composed mainly of fine-grained mudstones, siltstones, and sandstones deposited in terrestrial settings across parts of South Dakota, Nebraska, Colorado, Wyoming, and North Dakota. It records a relatively cool, dry interval with open savanna to floodplain environments and preserves a rich fossil assemblage of mammals such as three‑toed horses, oreodonts, and other classic White River fauna.