Tietasaura (meaning "Tieta lizard") is an extinct genus of elasmarian ornithopod dinosaur from the Early Cretaceous Marfim Formation of Brazil. The genus contains a single species, T. derbyiana, known from a single incomplete femur. Tietasaura is notable for being the first ornithischian dinosaur ever named from Brazil.
Tietasaura (meaning "Tieta lizard") is an extinct genus of elasmarian ornithopod dinosaur from the Early Cretaceous Marfim Formation of Brazil. The genus contains a single species, T. derbyiana, known from a single incomplete femur. Tietasaura is notable for being the first ornithischian dinosaur ever named from Brazil.
== Discovery and naming == thumb|left|Life restoration The Tietasaura holotype specimen, NHM-PV R.3424, was discovered in 1906 during a series of expeditions by London's Natural History Museum to South America, lasting from 1859 to 1906. Some of the fossils found during these trips were described in publications in 1860 and 1907. This particular fieldwork was conducted along a beach near the Bahia-São Francisco Railway in the city of Salvador in Bahia, Brazil. This locality belongs to the Marfim Formation of the Recôncavo Basin. The specimen, which consists of the distal end of left femur, is among the first dinosaur remains found in South America. While it is now confidently regarded as belonging to a dinosaur, early observations labeled the bone as belonging to "Hyposaurus sp." (a dyrosaurid crocodyliform) in the collections of the Natural History Museum, and the museum's digital collections inaccurately list it as a specimen of Sarcosuchus hartti (a pholidosaurid crocodyliform).
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).