A new armored crocodyliform from the Upper Cretaceous of Catalonia (Spain): new insight into the evolution of the eusuchian postcranial and dermal skeleton

Abstract

The origin and early radiation of Crocodylia have shifted attention to the Upper Cretaceous of Europe, where numerous new taxa have recently been discovered. Particularly abundant are the remains associated with allodaposuchids, a controversial and recently established eusuchian clade whose postcranial record is rarely documented. Here, we describe a new allodaposuchid specimen from the Fontllonga-6 fossil locality (Àger Basin, NE Spain) in the Fontllonga Group (lower upper Maastrichtian). The specimen consists of cranial, postcranial, and dermal skeleton remains, making it the most complete crocodyliform from the Upper Cretaceous of Europe. It exhibits massive vertebrae and a large ribcage, while the numerous recovered osteoderms show diverse morphologies, providing insight into their position within the dermal skeleton. It presents peculiar teeth ornamentation only observed in Allodaposuchus palustris in the Ibero-Armorican domain. However, confident taxonomic assignment remains challenging due to the lack of other diagnostic traits. Including anatomical information provided by the specimen in phylogenetic analyses underscores the significance of postcranial characters in reconstructing relationships within Eusuchia. This new finding fills a data gap in the postcranial anatomy of eusuchians and allodaposuchids, offering insights into the ecology of this successful clade from the Upper Cretaceous of Europe.