Mauriciosaurus fossil map
Where fossils of Mauriciosaurus 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 | 93.9–89.8 million years ago (Turonian) |
| Periods | Cretaceous |
| Family | Polycotylidae |
| Named by | Frey et al. 2017 |
| Fossil records | 1 occurrences at 1 locations (PBDB) |
| Found in | Mexico |
| Rock formations | Agua Nueva |
About Mauriciosaurus
Mauriciosaurus (meaning "Mauricio [Fernández Garza's] reptile") is a genus of polycotylid plesiosaur from the Late Cretaceous of Mexico. It contains a single species, M. fernandezi (also named after Fernández Garza), described in 2017 by Eberhard Frey and colleagues from a single well-preserved juvenile specimen about 2 metres (6 ft 7 in) long. Morphologically, it is overall most similar to the polycotyline polycotylids Trinacromerum and Dolichorhynchops. However, several features separate Mauriciosaurus from all other polycotylids, warranting the naming of a new genus. These include the sophisticated pattern of ridges on the bottom of the parasphenoid bone on its palate; the narrow openings in the palate bordered by the pterygoid bones; the lack of perforations in the surface of the coracoid; and the highly unusual arrangement of gastralia, or belly ribs, which is only otherwise seen in the non-polycotylid Cryptoclidus.
Text in “About” is quoted from the Wikipedia article Mauriciosaurus (revision 1358562429), 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: Q29032438.