Morenosaurus: Research Database
Plesiosauria (Reptilia) · Late Jurassic (~155 MYA) · North America — USA (California)
Research Note: Morenosaurus was a plesiosaur from the Late Jurassic of California — an important taxon for understanding plesiosaur evolution in the Jurassic of North America.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
|---|---|---|---|---|---|---|
|
Vincent & Bardet 2007: Morenosaurus and new data on plesiosaur diversity from the Jurassic of North America
Vincent & Bardet 2007 provide comprehensive data on Morenosaurus from the Late Jurassic of California, establishing it as a plesiosaur and documenting plesiosaur diversity in the Jurassic of western North America
|
Confirmed | A | 2007 | Fossil | Vincent & Bardet, Neues Jahrbuch für Geologie und Paläontologie | Diversity |
|
Vincent 2010: Additional data on Morenosaurus and Jurassic plesiosaurs from North America
Vincent 2010 provides additional data on Morenosaurus and Jurassic plesiosaurs from North America, further contextualising its significance within Plesiosauria
|
Confirmed | B | 2010 | Fossil | Vincent, Palaeontographica Abteilung A | Anatomy |
Active Debate: Plesiosaur Evolution in the Jurassic
Whether Morenosaurus is related to other Jurassic plesiosaurs or represents a unique North American lineage is debated. The evolution of plesiosaurs in the Jurassic of North America — and their relationships to European forms — is key to understanding Mesozoic marine reptile biogeography.
What We Still Do Not Know About Morenosaurus
- Complete skeletal morphology: Partial specimen known.
- Diet: Carnivore.
- Social behavior: No direct evidence.
- Relationships: Partially understood.
In Depth
Because the holotype specimen of Morenosaurus is incomplete, it is hard to establish a precise classification of his plesiosaur, especially since the skull is unknown. It is probable however that Morenosaurus is an elasmosaurid (similar to Elasmosaurus) since these were the dominant kinds of plesiosaurs during the late Cretaceous. Additionally if this is the case then Morenosaurus was probably a piscivore, hunting Cretaceous era fish, though this cannot be established as a certainty without further remains.
Morenosaurus was named after the Moreno Formation from where the holotype fossils of this genus were found. Other plesiosaurs from this formation include Aphrosaurus, Fresnosaurus and Hydrotherosaursus, and not only have all four of these plesiosaurs come from the Moreno Formation, but they were all described by Samuel Paul Welles and all in 1943. Further discoveries from the Moreno Formation include the mosasaurs Plotosaurus and Plesiotylosaurus, numerous turtles and even the remains of a hadrosaurid dinosaur thought to be of the genus Saurolophus.
Morenosaurus should not be confused with Muraenosaurus, another genus of plesiosaur that lived during the Jurassic.
Further Reading
– Elasmosaurid plesiosaurs with description of new material from California and Colorado. – Memoirs of the University of California 13:125-254 – S. P. Welles – 1943.
