Hierarchy classification:

1. top of the aat hierarchies
2. Agents Facet
3. Living Organisms (hierarchy name)
4. living organisms (entities)
5. Eukaryota (domain)
6. Animalia (kingdom)
7. Chordata (phylum)
8. Vertebrata (subphylum)
9. Reptilia (class)
10. Diapsida (subclass)

Anotations

Scope note:

Extinct order of fossil marine reptiles characterized by a broad, flattened body, often a small head often on long flexible neck, a short tail, and four large, paddle-like limbs, dating to the Jurassic and Cretaceous periods.