Dinosaur remains from the La Quinta Formation (Lower or Middle Jurassic) of the Venezuelan Andes

Abstract

Dinosaur remains are exceptionally scarce in northern South America and Jurassic faunas from this area are particularly poorly known. We provide descriptions of new dinosaur specimens from a bonebed in the La Quinta Formation (Early or Middle Jurassic) of western Venezuela. The specimens are disarticulated and associations of elements are rare, but at least two distinct taxa appear to be present. Ornithischian dinosaurs are identifi ed on the basis of isolated teeth and a distal tibia. The teeth represent a non-cerapodan basal ornithischian and possess a unique combination of character states, suggesting that they pertain to a new and unnamed taxon. Other remains represent an indeterminate basal saurischian (based on an ilium) and indeterminate dinosaurs (caudal vertebrae and a femur). The apparently plesiomorphic morphology of many of the dinosaurian remains is consistent with suggestions of an Early or Middle Jurassic age for the La Quinta Formation. Previous reports of the basal ornithischian LesothosaurusDinosaur remains are exceptionally scarce in northern South America and Jurassic faunas from this area are particularly poorly known. We provide descriptions of new dinosaur specimens from a bonebed in the La Quinta Formation (Early or Middle Jurassic) of western Venezuela. The specimens are disarticulated and associations of elements are rare, but at least two distinct taxa appear to be present. Ornithischian dinosaurs are identifi ed on the basis of isolated teeth and a distal tibia. The teeth represent a non-cerapodan basal ornithischian and possess a unique combination of character states, suggesting that they pertain to a new and unnamed taxon. Other remains represent an indeterminate basal saurischian (based on an ilium) and indeterminate dinosaurs (caudal vertebrae and a femur). The apparently plesiomorphic morphology of many of the dinosaurian remains is consistent with suggestions of an Early or Middle Jurassic age for the La Quinta Formation. Previous reports of the basal ornithischian LesothosaurusLesothosaurus sp. from the La Quinta Formation cannot be substantiated on the basis of available data.