Tenontosaurus fossil map
Where fossils of Tenontosaurus have been found, shown on the Earth as it looked about 100 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 100 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Iguanodonts & duck-bills |
|---|---|
| Lived | 121.4–93.9 million years ago (Aptian to Cenomanian) |
| Periods | Cretaceous |
| Family | Tenontosauridae |
| Named by | Ostrom 1970 |
| Fossil records | 83 occurrences at 53 locations (PBDB) |
| Found in | United States |
| Rock formations | Cloverly, Antlers, Cedar Mountain, Shellenberger Canyon, Arundel Clay, Twin Mountains |
About Tenontosaurus
Tenontosaurus ( ti-NON-tə-SOR-əs; lit. 'sinew lizard') is a genus of iguanodontian ornithopod dinosaur. It had an unusually long, broad tail, which like its back was stiffened with a network of bony tendons. The genus is known from the late Aptian to Albian ages of the Early Cretaceous period sediments of western North America, dating between 115 and 108 million years ago. It contains two species, Tenontosaurus tilletti (described by John Ostrom in 1970) and Tenontosaurus dossi (described by Winkler, Murry, and Jacobs in 1997). Many specimens of T. tilletti have been collected from several geological formations throughout western North America. T. dossi is known from only a handful of specimens collected from the Twin Mountains Formation of Parker County, Texas.
Text in “About” is quoted from the Wikipedia article Tenontosaurus (revision 1380244645), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 22 October 2026. Ages are those of the rock layers the fossils were found in.
