Morenosaurus fossil map
Where fossils of Morenosaurus have been found, shown on the Earth as it looked about 66 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 66 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 | 72.2–66 million years ago (Maastrichtian) |
| Periods | Cretaceous |
| Family | Elasmosauridae |
| Named by | Welles 1943 |
| Fossil records | 2 occurrences at 2 locations (PBDB) |
| Found in | United States |
| Rock formations | Moreno |
About Morenosaurus
Morenosaurus is an extinct genus of plesiosaur from the Cretaceous of what is now California. The type species is Morenosaurus stocki, first named by Samuel Welles in 1943, in honor of Dr. Chester Stock. The species was found by Robert Wallace and Arthur Drescher in the Panoche Hills region of Fresno County. The skeleton they found was fairly complete, and lacked only the head and parts of the neck and paddles; the preserved portion of the trunk and tail is 3.63 metres (11.9 ft) long. The skeleton was originally mounted at Caltech but is now in the Natural History Museum of Los Angeles County.
Morenosaurus may have been similar to Elasmosaurus or Thalassomedon, but studies in the early 2000s indicated that the fossils were too scrappy to identify to the family level.
Text in “About” is quoted from the Wikipedia article Morenosaurus (revision 1366937073), 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: Q6911404.
