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Lower Cretaceous Dinosaur Footprints from Northern South America and the Relationships between Gondwanan and Laurasian Ornithopods
By Leslie F. NOÈ, Marcela GÓMEZ–PÉREZ, José Vicente RODRÍGUEZ, Alejandro CORRALES-GARCÍA , and William G. CARANTON-MATEUS
Dinosaur remains from northwestern South America are rare, with only extremely scarce fossil evidence recovered from Colombia. Here we report six dinosaur footprints preserved on a sub–vertical bedding plane of the late Valanginian – early Hauterivian Batá Formation, Santa María, Department of Boyacá, Colombia. The Batá Formation consists of a thick succession of conglomerates and sandstones with shale intercalations interpreted as deposited along the palaeoshoreline of an epicontinental seaway. Four of the footprints form a trackway made by a single dinosaur, which is interpreted as a sub–adult ornithopod, estimated at 8 m in length, weighing around 2.5 metric tons, and travelling at an average walking pace of almost 5 km/h. The footprints are assigned to the ichnogenus Iguanodontipus, and were probably made by an iguanodontid dinosaur. Prior to this work, Iguanodontipus was considered an exclusively European taxon, making this a unique record of the ichnogenus in Gondwana. The presence of Iguanodontipus in northern South America suggests an Early Cretaceous sweepstake crossing of Tethys Ocean into modern–day northern Africa, and migration along the northern shores of Gondwana into modern–day South America. Range extension of iguanodontian ornithopods southwards into Gondwana was apparently prevented by the Central Gondwana Desert Belt, possibly as a result of the palaeoecology of these dinosaurs, which seem to have an affinity for water and lush vegetation. A migration route across Tethys and the Central Gondwana Desert Belt helps explain similarities between northern Gondwanan and southern Laurasian dinosaurs, and the differences between northern and southern Gondwanan faunas, during the Early Cretaceous.
Keywords: dinosaur footprints, Lower Cretaceous, South America, Gondwana, Laurasia.