Alzadasaurus
Alzadasaurus was a long-necked marine reptile that swam in the seas of North America about 80 million years ago. It was not a dinosaur, but a plesiosaur, and it used its four flippers to paddle through the water. With sharp teeth, it hunted fish and other sea creatures.4
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Fun facts
Alzadasaurus lived during the Late Cretaceous period, between about 83.6 and 72.2 million years ago.1
It belonged to a group of plesiosaurs called elasmosaurids, which had very long necks.4
Fossils of Alzadasaurus have been found in the Bearpaw Shale formation in Montana.4
Some scientists think Alzadasaurus might actually be the same animal as Thalassomedon, another elasmosaurid.4
Alzadasaurus was named by paleontologist Samuel Paul Welles in 1943.4
It is the type genus of the subfamily Alzadasaurinae, a group of elasmosaurids.4
Most asked questions about Alzadasaurus
?How big was Alzadasaurus?
Scientists are not sure of its exact size, but its close relative Thalassomedon was about 10.86 to 11.95 metres long and weighed 4.4 to 6.8 metric tons.2
?What did Alzadasaurus eat?
It was a carnivore that ate fish and other sea creatures, using its sharp teeth to catch them.4
?Is Alzadasaurus a dinosaur?
No, it is a plesiosaur, a marine reptile that lived in the sea. It is not a dinosaur.4
?When did Alzadasaurus live?
It lived during the Late Cretaceous period, between about 83.6 and 72.2 million years ago.4
?Could Alzadasaurus swim?
Yes, it was an aquatic marine reptile that used its four flippers to paddle through the water.4
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For dino experts
- Scientific name
- Alzadasaurus
- Named by
- Welles 19434
- Group
- Plesiosaurs
- Family / clade
- Elasmosauridae4
- Classification
- Plesiosauria > Elasmosauridae > Sauropterygia4
- Age of the rocks
- 84 to 72 million years (Campanian)4
- Rock formations
- Bearpaw Shale4
- Countries
- USA4
- Fossil records
- 1 in the Paleobiology Database4
- Discovery
- Alzadasaurus was named by Samuel Paul Welles in 1943 based on fossils found in Montana, USA.4
- Still debated
- Scientists are not sure if Alzadasaurus is a distinct genus or if it should be considered the same as Thalassomedon.4
Where the facts come from
- PBDB Taxon (paleobiodb.org)
- Thalassomedon (en.wikipedia.org)
- Alzadasaurus pembertoni, a new elasmosaur from the Upper Cretaceous of South Dakota (exa.ai)
- Alzadasaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.
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