1991 in paleontology
Arthropods
Newly named insects
Mollusca
Newly named bivalves
Archosauromorphs
- Sankar Chatterjee's discovery of a possible Triassic bird, Protoavis, if genuine, would push avian origins back almost 70 million years. The find ignites controversy over the connection between dinosaurs and birds.
Newly named dinosaurs
| Name | Status | Authors | Age | Unit | Location | Notes | Images |
Alvarezsaurus | Valid taxon | Jose Bonaparte | Late Cretaceous | Bajo de la Carpa Formation | An alvarezsaurid. | ||
Amargasaurus | Valid taxon | Salgado and Jose Bonaparte | Early Cretaceous | La Amarga Formation | A dicraeosaurid. with Spines on its Neck | ||
Amurosaurus | Valid taxon | Bolotsky & Kurzanov | Late Cretaceous | Udurchukan Formation | A lambeosaurine hadrosaurid. | ||
Andesaurus | Valid taxon | Calvo and Bonaparte | Late Cretaceous | Bajo de la Carpa Formation | An alvarezsaurid. | ||
Becklespinax | Junior synonym | George Olshevsky. | Early Cretaceous | Wadhurst Clay Formation | A junior objective synonym of Altispinax; new genus for "Acrocanthosaurus" altispinax Paul. | ||
Euronychodon | Valid taxon | Telles-Antunes & Sigogneau-Russell | Late Cretaceous | A troodontid. | |||
| Janenschia | Valid taxon | Wild | Late Jurassic | Tendaguru Formation | A non-titanosauriform macronarian; new genus for "Gigantosaurus" robustus E. Fraas. | ||
Protognathosaurus | Valid taxon | George Olshevsky | Middle Jurassic | Xiashaximiao Formation | A sauropod of uncertain affinities. | ||
"Rioarribasaurus" | Junior synonym | Hunt & S.G. Lucas | Late Triassic | A junior synonym of Coelophysis. | |||
"Seismosaurus" | Junior synonym | Gillette | |||||
Tarascosaurus | Valid taxon | Le Loeuff and Buffetaut | |||||
| Taveirosaurus | Valid taxon | Telles-Antunes & Sigogneau-Russell | Late Cretaceous | An ornithischian of unknown affinities. | |||
| Tochisaurus | Valid taxon | Kurzanov and Osmolska | Cretaceous | - | - | ||
| "Ultrasauros" | Junior synonym | George Olshevsky | Late Jurassic | Morrison Formation | Junior synonym of Supersaurus; replacement name for Ultrasaurus Jensen 1985. | ||
Valdoraptor | Valid taxon | George Olshevsky | Early Cretaceous | Tunbridge Wells Formation | An ornithomimosaur; new genus for "Megalosaurus" oweni Lydekker. | ||
Velocisaurus | Valid taxon | Jose Bonaparte | A Noasaur. | '' |
Newly named birds
Genera no longer considered to be birds
- Protoavis. The avian status of Protoavis has since been almost universally rejected by paleontologists.
Pterosaurs
New taxa
Synapsids
Non-mammalian
| Name | Status | Authors | Age | Unit | Location | Notes | Images |
Apsisaurus | Valid |
| Lower Permian | Archer City Formation | Formerly assigned as an eosuchian diapsid, was restudied an classified as a varanopid synapsid. | ||
Ctenorhachis | Valid |
| Upper Permian | A sphenacodontid synapsid. |