| Named By: | Alexander Wilhelm Armin Kellner, Sergio A.K. Azevedeo, Elaine B. Machado, Luciana B. Carvalho & Deise D.R. Henriques in 2011 |
| Time Period: | Early-Late Cretaceous, 98 Ma |
| Location: | Brazil, Cajual Island - Alcantara Formation |
| Size: | Estimated between 12 and 14 meters long |
| Diet: | Piscivore |
| Fossil(s): | Single fused premaxillae, fragment of the left maxilla |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Theropoda | Spinosauridae | Spinosaurinae | |
Oxalaia is a genus of carnivorous theropod. It is a spinosaurine spinosaurid which lived during the late Cretaceous (early Cenomanian stage, about 98 mya) in what is now Brazil.
Oxalaia is known from the holotype MN 6117-V, fused premaxillae of a very large individual and from the referred fragment MN 6119-V, an isolated and incomplete left maxilla, which were found on Cajual Island, Maranhao of northeastern Brazil. Fossils of Oxalaia were recovered in 2004 from the Laje do Coringa locality of the Alcantara Formation, part of the Itapecuru Group of the Sao Luis Basin. Besides these bone fragments, numerous spinosaurid teeth had earlier been reported from the site.
The genus was named by Alexander Wilhelm Armin Kellner, Sergio A.K. Azevedeo, Elaine B. Machado, Luciana B. Carvalho and Deise D.R. Henriques in 2011 and the type species is Oxalaia quilombensis. The specific name quilombensis refers to the quilombo settlements, such as on Cajual Island, which were founded by escaped slaves. Estimates suggest that it was 12 to 14 metres (39 to 46 ft) in length and 5 to 7 tonnes (5.5 to 7.7 short tons) in weight --- it is the largest theropod known from Brazil and the eighth officially named species of theropod from Brazil.