Amazonsaurus

Amazonsaurus ( AM-ə-zən-SOR-əs, 'Amazon lizard') is a genus of diplodocoid sauropod dinosaur from the Early Cretaceous Period of what is now South America. It would have been a large-bodied quadrupedal herbivore with a long neck and whiplash tail. Although more derived diplodocoids were some of the longest animals ever to exist, Amazonsaurus was probably not more than 12 meters (40 ft) long. Gregory S. Paul estimated in 2010 its weight at 5000 kg.

Fossils of Amazonsaurus, including some back and tail vertebrae, ribs, and fragments of the pelvis, are the only dinosaur remains identifiable at the generic level from the Itapecuru Formation of Maranhão. This geologic formation dates back to the Aptian through Albian epochs of the Early Cretaceous, or about 125 to 100 million years ago. Amazonsaurus was recovered in sediments which are interpreted by geologists as floodplain deposits near a river delta.

Discovery and naming

Fossils of Amazonsaurus were first unearthed in the Mata locality in Itapecuru-Mirim County, Maranhão Province in the Brazilian Amazon. They were collected during a Brazilian expedition to the Lower Cretaceous-aged strata of the Itapecuru Formation of the Parnaíba Basin, a stretch of intracratonic rocks that covers much of northeastern Brazil. Over the course of its excavation, researchers collected a single, associated sauropod skeleton including two dorsal vertebral neural spines, two dorsal centra, a neural spine of an anterior caudal vertebra, four caudal vertebrae, eight chevrons, an ilium, an incomplete pubis, and three ribs.