Santanaraptor

Santanaraptor (meaning "Santana Formation thief") is a genus of Theropoda dinosaur that lived in South America during the Albian[1] or Aptian[2] stage of the Early Cretaceous, about 108 million years ago. It is known from a partial juvenile specimen recovered with fragments of mineralized soft tissue, including, muscle and skin tissue, but unfortunately not trace of the skins external covering, which was unearthed in 1996 from the Santana Formation of Ceará, northeastern Brazil.[3] While primarily known from hindquarter elements, the individual represented by the fossil may have reached 1.25 metres (4.1 ft) in length.[1] The fossil consists of bones from the pelvis, hindlimbs, and tail. These provide little information on its overall appearance. However, it was definitely a Coelurosauria, and a few of its details suggest that it might be an ancestor of the tyrannosauroids. It is presumed to be similar to Dilong and Guanlong and that it had long arms, three fingered hands, and slim hindlimbs.[3] Santanaraptor is thought by some paleontologists to be the first tyrannosauroid known from Gondwana,[2][4] but it may be a more basal coelurosaur.

Classification
The holotype (MN 4802-V) consists of 3 caudal vertebrae with chevrons, ischia, femora, tibia, fibula, pes, and soft tissue. The fossilized tissue includes a thin epidermis, muscle fibers, and possibly blood vessels.[1]

The type species is S. placidus, first described by Kellner in 1999.[5] The species epithet refers to Placido Cidade Nuvens, who founded the Museo de Santana do Cariri.[1]

Santanaraptor was originally thought to be a maniraptoran theropod when it was first discovered. However, it is now thought to be a basal coelurosaur based on several features present on the femur. Santanaraptor may have been closely related to Ornitholestes, an earlier coelurosaur of the Late Jurassic, based on similarities in the ischium, a bone of the pelvis.