Polycotylus fossil map
Where fossils of Polycotylus have been found, shown on the Earth as it looked about 85 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 85 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 | Plesiosaurs & kin |
|---|---|
| Lived | 152.21–72.2 million years ago (Kimmeridgian to Campanian) |
| Periods | Jurassic, Cretaceous |
| Family | Polycotylidae |
| Named by | Cope 1869 |
| Fossil records | 10 occurrences at 10 locations (PBDB) |
| Found in | United States, France, Russia |
| Rock formations | Niobrara, Frontier, Mooreville Chalk, Pierre Shale, Argiles de Châtillon, txn:100152 |
About Polycotylus
Polycotylus is a genus of plesiosaur within the family Polycotylidae. The type species is P. latippinis and was named by American paleontologist Edward Drinker Cope in 1869. Eleven other species have been identified. The name means 'much-cupped vertebrae', referring to the shape of the vertebrae. It lived in the Western Interior Seaway of North America toward the end of the Cretaceous. One fossil preserves an adult with a single large fetus inside of it, indicating that Polycotylus gave live birth, an unusual adaptation among reptiles.
Text in “About” is quoted from the Wikipedia article Polycotylus (revision 1354841144), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q1886121.
