Alvarezsaurus
Alvarezsaurus, skeletal reconstruction
- South America ( Argentina)
Alvarezsaurus ( " Alvarezechse ") is a genus theropod dinosaur from the Upper Cretaceous ( Turonian to Santonian ) of South America. Its fossils have been dated to an age of about 94-86 million years ago and were found in Argentina. Alvarezsaurus was a basal member of the eponymous family Alvarezsauridae.
A skeleton without skull was found in 1987 in the Bajo de la Carpa - formation on the banks of the Rio Colorado, and in 1991 described by paleontologist José Fernando Bonaparte scientifically. The genus was named after the Argentine historian Gregorio Alvarez.
Alvarezsaurus was probably a fast runner and had a tail, which occupied about two-thirds of the total length of the animal. Probably Alvarezsaurus was about 2 feet long and weighed about 20 kilograms. He probably fed on insects. He probably wore feathers, so he was probably endothermic.
Alvarezsaurus was a basal Alvarezsauridae. Typical of this group was the hand; they had only one claw. Cladogram according to Xu et al (2011):
Achillesaurus
Alvarezsaurus
Patagonykus
Parvicursorinae