Ibirania parva Navarro et al., 2022 (new genus and species)
(Back vertebra [top, scale bar = 10 cm] and schematic skeletal [bottom, scale bar = 1 m, with preserved bones of the type specimen in orange and those of other specimens in blue] of Ibirania parva, from Navarro et al., 2022)
Meaning of name: Ibirania = Ibirá wanderer [in Greek] (can also be interpreted as “tree wanderer”, as Ibirá is a Portuguese derivative of the Tupi word for “tree”); parva = small [in Latin]
Age: Late Cretaceous (Santonian–Campanian)
Where found: São José do Rio Preto Formation, São Paulo, Brazil
How much is known: Remains of several individuals, including vertebrae and limb bones.
Notes: Ibirania was a titanosaurian sauropod. Although titanosaurs included the largest known land animals of all time, Ibirania is one of the smallest sauropods discovered so far, estimated as having been about 5.7 m long. Examination of the microscopic structure of its bones indicates that the known specimens of Ibirania had reached adulthood before they died, suggesting that their small size was not the result of being at a juvenile growth stage.
Other sauropods of comparable size to Ibirania are known largely from island environments, but Ibirania appears to have lived far inland. It is possible that prolonged periods of aridity in its habitat limited resources in a way similar to islands, thus favoring the evolution of smaller body sizes in this sauropod.
Reference: Navarro, B.A., A.M. Ghilardi, T. Aureliano, V. Díez Díaz, K.L.N. Bandeira, A.G.S. Cattaruzzi, F.V. Iori, A.M. Martine, A.B. Carvalho, L.E. Anelli, M.A. Fernandes, and H. Zaher. 2022. A new nanoid titanosaur (Dinosauria: Sauropoda) from the Upper Cretaceous of Brazil. Ameghiniana 59: 317–354. doi: 10.5710/AMGH.25.08.2022.3477
