Ostracotheridae

Ostracotheridae is an extinct family of Mesozoic mammals belonging to the order Multituberculata. These small, rodent-like creatures lived during the Cretaceous period and into the early Paleogene. Fossil evidence suggests they were widespread across North America and Eurasia. Multituberculates, including ostracotherids, are characterized by their unique dental formula, particularly the presence of large, specialized incisors and a row of premolars that often appear molar-like. Their molars typically possessed multiple cusps arranged in a specific pattern, which gave the order its name.

The exact diet and lifestyle of Ostracotheridae are not definitively known, but based on their dentition and the typical adaptations of multituberculates, they are presumed to have been herbivores or possibly omnivores. Their teeth were well-suited for grinding tough plant material. Fossil remains are often found in terrestrial sedimentary deposits, suggesting they inhabited a variety of environments, likely including forests and open woodlands. The extinction of the Ostracotheridae, along with the rest of the Multituberculata, occurred during the Paleogene, possibly due to competition with the rapidly diversifying placental mammals that emerged after the K-Pg extinction event. They represent a significant branch of early mammalian evolution.