FIRST EVIDENCE OF A PATHOLOGICAL PHALANX IN A CTENOCHASMATIDAE PTEROSAUR FROM THE LOWER CRETACEOUS OF SAN LUIS, ARGENTINA

GONZÁLEZ ROMINA; CODORNIU LAURA

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Jornada; XXXV Jornadas Argentinas de paleontologia de Vertebrados; 2024

Museo Paleontológico Egidio Feruglio

Paleopathology is the study of diseases and traumatic injuries that cause visible abnormalities of theskeleton in fossil vertebrates. In pterosaurs, only very few osteopathologies cases have beenmentioned, such as infections, arthritis and possible tumors, being the fractures rarely reported. Theaim of this work is to describe and analyze a bone anomaly present in an isolated third phalanx of thewing finger (MIC-V47) referred to Pterodaustro guinazui. The phalanx MIC-V47 was recovered fromoutcrops at the “Loma del Pterodaustro” site, from Lagarcito Formation (Lower Cretaceous). Thematerial is deposited at the collection of the Museo Interactivo de Ciencias (MIC), San Luis, Argentina.Based on comparisons with observations from the paleopathological and modern veterinaryliterature, potential etiologies are discussed. Macroscopic examination reveals that MIC-V47 exhibitsa conspicuous bowing and a localized proliferative bone growth. This extends around the entirecircumference of the distal diaphysis. The surface of the bone growth is mainly smooth withexception of certain areas where an irregular texture is observed. The rest of the phalanx shows arobust appearance compared with other phalanges preserved of the same species. The abnormalbone of the phalanx is consistent with a fracture followed by infection, but other possible causes suchas osteopetrosis cannot be ruled out. Additional information regarding the internal aspect of theelement, such as that derived from histological or computed tomography data is necessary to clarifythe cause of the anomaly. Poor healing of the infection could lead to misalignment of the fracturedparts, which possibly compromised the individual survival.