Brazilian, Spanish researchers reassess pterosaur from Triassic Period

A reassessment of Faxinalipterus minimus, supposedly a Triassic pterosaur from southern Brazil, resulted in the creation of a new taxon, according to a Science Daily article published May 4.

A study published in the scientific journal PeerJ has described the taxon Maehary bonapartei as a small reptile considered to be the most basal of the evolutionary lineage that gave rise to pterosaurs. 

Researchers from institutions such as the National Museum/UFRJ in Rio de Janeiro and the Catalan Institute of Paleontology in Barcelona, Spain, re-evaluated Faxinalipterus minimus and found that it was not, as was once thought, a winged reptile.

The original Faxinalipterus fossil was composed of bones from a postcranial skeleton and an upper jaw with multiple teeth found in two separate field expeditions in 2002 and 2005 at the Linha São Luiz fossil site in the Faxinal do Soturno municipality in southern Brazil. 

Although it wasn't possible to decisively tell whether the fossils belonged to the same type of animal, scientists assumed that they belonged to a single species dubbed Faxinalipterus minimus. The recent study, however, revealed that the jaw came from another creature, meaning there were two distinct species involved instead of one. 

The determination was made based on a comparison with a new fossil recently unearthed at the same site composed of an incomplete skull that has details matching those found in the original Faxinalipterus skull, and other parts of the mandible, scapula, and vertebrae.

"There was always a great doubt whether the two specimens attributed to Faxinalipterus represented the same species and whether this was a flying reptile," said National Museum/UFRJ Director Alexander Kellner.

Scientists used computed tomography to perform a non-destructive analysis to visualize the anatomical details still hidden under the sedimentary rock where the fossil was preserved. 

The examination of the initial specimen found that several bones could have been misidentified and that there was a lack of the typical diagnostic features of pterosaurs, including a large and projected deltopectoral crest on the humerus, or forelimb bone. The researchers concluded that both Faxinalipterus and Maehary were primitive reptiles that didn't fit in the pterosaur lineage.