Thiornis
| Thiornis Temporal range:  | |
|---|---|
| Fossil slab of Thiornis sociata | |
| Scientific classification | |
| Domain: | Eukaryota | 
| Kingdom: | Animalia | 
| Phylum: | Chordata | 
| Class: | Aves | 
| Order: | Podicipediformes | 
| Family: | Podicipedidae | 
| Genus: | †Thiornis Navás, 1922 | 
| Type species | |
| †Thiornis sociata | |
| Synonyms | |
| Podiceps sociatus (Navás, 1922) sensu Olson, 1995 | |
Thiornis is a fossil genus of Middle Miocene grebe known from a nearly complete specimen from Libros, Spain. Originally classified as a type of moorhen, Thiornis has since been classified as a species of grebe. The overall anatomy of the bird is identical to modern grebes. It contains a single species, T. sociata.