Apatosaurinae Tooth-Colorado

Taxa: Indeterminate Apatosaurinae

Geology: Morrison formation

Age: Jurassic

Locality: Moffat County, Colorado

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Morrison Formation

The Morrison Formation is a widespread sequence of sedimentary rocks from the Late Jurassic period (about 155–148 million years ago) found across the western United States, from Montana to New Mexico. It is composed mainly of mudstone, sandstone, siltstone, and limestone, and is famous for its rich dinosaur fossil beds. These rocks were deposited in river floodplains, lakes, and swamps, reflecting a variety of ancient environments. The Morrison Formation is the most productive source of Jurassic dinosaur fossils in North America.

Apatosaurinae

Apatosaurinae from the Morrison Formation were large, robust sauropod dinosaurs—including Apatosaurus and Brontosaurus—that lived during the Late Jurassic (about 156–147 million years ago). They had long necks with boxy, strong vertebrae, whip-like tails, and peg-like teeth adapted for nonselective low browsing on tough plants like ferns, cycads, and horsetails. Apatosaurines grew rapidly, reaching adult size in about ten years, and their fossils are widespread across the Morrison Formation in the western United States. They coexisted with a diverse dinosaur fauna and were among the most common sauropods in their ecosystem, playing a key role in the semiarid, seasonally variable environments of the Morrison Basin.