Pterosaur tracks from the Cenomanian (Upper Cretaceous) Candeleros Formation of northern Patagonia: ichnotaxonomical and palaeoecological perspectives from Gondwana

HEREDIA ARTURO M.; DÍAZ-MARTÍNEZ IGNACIO; PAZOS PABLO J.; DE VALAIS SILVINA

Khon Kaen

Congreso; 6th International Palaeontological Congress; 2022

International Palaeontological Association

New Cenomanian pterosaur tracks from the Aguada de Tuco tracksite, Neuquén Basin, Argentina, are described here. They are preserved in medium-grained sandstones from fluvial deposits of the Candeleros Formation. The tracks consist of both manus and pes impressions generally isolated, although some of them are probably part of trackways. Manus tracks are tridactyl, longer than wide (length range 6.3–14.7 cm and width range 2.6–8.0 cm), and strongly asymmetrical, while the pes tracks are longer than wide (length range 7.5–13.7 cm and width range 2.7–6.8 cm), trapezoidal to subtriangular, and preserve three-digit impressions. Although the pterosaur tracks from Aguada de Tuco show general similarities with the ichnogenus Pteraichnus, it is possible that they are part of a new ichnotaxon due to their particular biomorphic and morphometric features. The pterosaur osteological record of the Candeleros Formation is composed only of indeterminate pterodactyloid remains, but in the nearby Albian Lagarcito Formation several complete pterodactyloid ctenochasmatids were found (Codorniú and Chiappe, 2004; Haluza and Canale, 2013). Considering the similarities between the study tracks and the pterosaur autopods preserved from the last unit, we propose to the pterodactyloid ctenochasmatids as probable trackmakers. The pterosaur tracks from Aguada de Tuco are similar in shape but have different sizes, so the tracksite may represent a multi-age gregarious behaviour, similar to those proposed from fossil pterosaur remains from the Lagarcito Formation. Pterosaur tracks are relatively abundant from North America, Europe and Asia, they are little known from Africa and South America and indeed completely unknown from Australia and Antarctica (Calvo and Lockley, 2001; Lockley et al., 2008; Heredia, 2020). The present study contributes to the knowledge of the poorly pterosaur track record from Gondwana and for the Late Cretaceous record worldwide.