Jurassic vertebrate tracks and traces

Jurassic vertebrate traces are abundant, diverse, and widespread across Asia, Europe, and North America. In Australia and South America, their diversity is slightly lower, while in Africa they are both abundant and diverse, mainly concentrated in Morocco and in the Lower Jurassic of southern Africa. Jurassic tracks are as yet unreported from Antarctica. Currently, there are more than 80 recognized Jurassic ichnogenera, attributed to fishes, amphibians, turtles, lepidosaurs, crocodylomorphs, pterosaurs, mammaliamorphs and various types of theropod, sauropodomorph, and ornithischian dinosaurs. These traces document the emergence of dinosaur-dominated ecosystems during the early part of the Jurassic and share some similarities with the track faunas of the first half of the Cretaceous, but they differ markedly from Triassic ichnofaunas. Among Jurassic vertebrate traces are records of limping, running, and crouching theropod dinosaurs, a rare instance of a sauropod dragging its tail, swimming dinosaurs, burrowing mammaliamorphs, walking and swimming crocodylomorphs and turtles, walking pterosaurs, and animals turning—all examples of behavioral acts preserved by the ichnites. Jurassic footprints can be found in several depositional environments, including alluvial floodplains, river sand bars, lake margins, tidal flats, sand dunes, and desert oases, among others. The compositions of the ichnoassociations in these settings vary, particularly in the abundances of different ichnotaxa.