Thalassomedon
| Thalassomedon Temporal range: Late Cretaceous,  | |
|---|---|
| Mounted cast of the type specimen, American Museum of Natural History | |
| Scientific classification | |
| Domain: | Eukaryota | 
| Kingdom: | Animalia | 
| Phylum: | Chordata | 
| Class: | Reptilia | 
| Superorder: | †Sauropterygia | 
| Order: | †Plesiosauria | 
| Family: | †Elasmosauridae | 
| Genus: | †Thalassomedon Welles, 1943 | 
| Species: | †T. haningtoni | 
| Binomial name | |
| †Thalassomedon haningtoni Welles, 1943 | |
| Synonyms | |
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Thalassomedon (from Greek, thalassa, "sea" and Greek, medon, "lord" or "ruler", meaning "sea lord") is a genus of plesiosaur, named by Welles in 1943.