Abstract
Pliosaurids were the dominant macropredators in aquatic environments at least since the Middle Jurassic until their extinction in the early Late Cretaceous. Until very recently, the Cretaceous record of Pliosauridae has been poor and difficult to interpret from the taxonomic and phylogenetic perspective. Despite that the knowledge of Cretaceous pliosaurids improved in recent years, numerous aspects of their evolutionary history still remain only poorly known. Here, we report the first pliosaurid material from Venezuela. The taxon is most likely earliest Cenomanian in age, thus representing the youngest occurrence of Pliosauridae from South America. The Venezuelan taxon is based on a well-preserved tooth crown whose morphology and outer enamel structural elements appear to resemble especially those observable in the giant pliosaurid Sachicasaurus vitae from the Lower Cretaceous of Colombia. The new discovery extends the pliosaurid record on the continent by more than 10 million years and likely marks the southernmost Upper Cretaceous occurrence of Pliosauridae, worldwide. We also briefly discuss the affinities of the enigmatic Venezuelan elasmosaurid Alzadasaurus tropicus and highlight similarities to elasmosaurids from the Western Interior Seaway.
Highlights
Pliosaurids were the dominant macropredators in aquatic environments at least since the Middle Jurassic until their extinction in the early Late Cretaceous
With the appearance of the Thalassophonea, possibly around the Early-Middle Jurassic transitional interval[1], pliosaurids became the dominant macropredators in the aquatic environments
Despite that the knowledge of the Cretaceous thalassophonean pliosaurids has improved in recent years, still considerable efforts are necessary to obtain an accurate perception of the clade’s diversity, disparity, and dispersal patterns during the final tens of millions of years of their evolutionary history
Summary
The new specimen originates from the midCretaceous succession of the La Luna Formation, Candelaria Municipality, Trujillo state, western Venezuela (Fig. 1)[37,38,39,40] This find is significant because it represents the youngest record of Pliosauridae from the South American continent; younger by more than 10 million years than the late Aptian (late Early Cretaceous) ‘Kronosaurus’ boyacensis, the second youngest South American record[15]. It is very likely the southernmost Upper Cretaceous occurrence of the clade, worldwide. They are often represented by Scientific Reports | (2021) 11:15501
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