MEANING: Southern thief
PERIOD: Late Cretaceous
CONTINENT: South America
Austroraptor is a large dromaeosaurid dinosaur that lived during the Late Cretaceous Period in what is now Argentina. It is the largest dromaeosaur to be discovered in the Southern Hemisphere, estimated at around 5-6 m in length, and weighing about 300 kg. The skull is low and elongated, much more so than that of other dromaeosaurs, and bore relatively small teeth. Austroraptor is particularly notable because of its relatively short forearms, which are much shorter in proportion when compared to the majority of the members of Dromaeosauridae.
Austroraptor is from the Cretaceous. The Cretaceous is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period.
The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct flora and fauna, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.
The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras.
Austroraptor is a dromaeosaur. Dromaeosauridae is a family of feathered theropod dinosaurs that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards'. Dromaeosaurids were small to medium-sized carnivores, ranging from about 0.5 to 6 meters in length. Smaller species included Microraptor and Velociraptor, while larger examples included species such as Utahraptor, Dakotaraptor and Achillobator.
The dromaeosaurid body plan includes a relatively large skull, serrated teeth, narrow snout, and forward-facing eyes which indicate some degree of binocular vision. The distinctive dromaeosaurid body plan helped to rekindle theories that dinosaurs may have been active, fast, and closely related to birds. Dromaeosaurids, like most other theropods, had a moderately long S-curved neck, and their trunk was relatively short and deep. They had long arms that could be folded against the body in some species, and relatively large hands with three long fingers ending in large claws. Their tails were long and slender, which helped them balance and quickly maneuver during locomotion.
Dromaeosaurid feet had an enlarged second toe, bearing an unusually large, curved, sickle-shaped claw, which was held off the ground or 'retracted' when walking. This distinctive claw is thought to have been used in capturing prey and climbing trees. It was especially blade-like in the large-bodied predatory eudromaeosaurs.