Juvenile notosuchian crocodiles from the La Buitrera Paleontological area with comments on qualitative ontogenetic characters

Abstract

Araripesuchus is a genus of medium-sized (approximately 1 m long) terrestrial uruguaysuchid crocodyliforms that lived during the Cretaceous in Gondwana. There is limited information about juvenile notosuchian specimens due to the scarcity of well-preserved fossils from ontogenetic series. This study presents a comprehensive morphological description of three juvenile specimens of Araripesuchus (MPCA PV 259, 624, and 1193) from the La Buitrera Paleontological Area, Patagonia, Argentina. These early developmental-stage specimens were identified at a generic level due to the absence of mature anatomical characters for precise classification. Variations were observed between these juveniles and the previously examined adult specimens from the same region. As a result, a list of characters indicating ontogenetic variants was provided. These characters represent discrete traits that vary throughout the life of the individuals and could serve as ontogenetic indicators. This study offers a deeper understanding of the skeletal anatomy of Araripesuchus and its range of morphological variation, providing new data for the characterization of the genus and potential new taxa of uruguaysuchids.