Қаңқасы бар ерте юралық жыртқыш динозавр: Cryolophosaurus

Genus of theropod dinosaur from the early Jurassic period

Cryolophosaurus (,/k//r//aɪ//@/,/l//oʊ//f//@/'/s//ɔːr//ə//s/ or /k//r//aɪ/,/ɒ//l//@//f//@/'/s//ɔːr//ə//s/; KRY ə LOH fə SAWR əs) is a genus of large theropod dinosaur known from only a single species Cryolophosaurus ellioti, from the early Jurassic of Antarctica. It was one of the largest theropods of the Early Jurassic, with the subadult being estimated to have reached long and weighed
Cryolophosaurus was first excavated from Antarctica's Early Jurassic, Pliensbachian aged Hanson Formation, formerly the upper Falla Formation, by paleontologist Dr. William Hammer in 1991. It was the first carnivorous dinosaur to be discovered in Antarctica and the first non avian dinosaur from the continent to be officially named. The sediments in which its fossils were found have been dated at ~196 to 188 million years ago, representing the Early Jurassic Period. Cryolophosaurus is known from a skull, a femur and other material, all of which have caused its classification to vary greatly. The femur possesses many primitive characteristics that have classified Cryolophosaurus as a dilophosaurid or a neotheropod outside of Dilophosauridae and Averostra, whereas the skull has many advanced features, leading the genus to be considered a tetanuran, an abelisaurid, a ceratosaur and even an allosaurid. In 2016 Molina Pérez and Larramendi gave a larger estimation of 7.7 meters (25.3 ft) and 780 kg (1,720 lb). Some researchers noted that the holotype individual probably represents a sub adult, so adults could have been larger.

The holotype of Cryolophosaurus consists of a high, narrow skull, which was discovered articulated with the rest of the skeleton. The crest is an extension of the skull bones, near the tear ducts, fused on either side to orbital horns which rise from the eye sockets. While other theropods like the Monolophosaurus have crests, they usually run along the skull instead of across it.

Classification of Cryolophosaurus is difficult because it has a mix of primitive and advanced characteristics. In 2020, a monograph of Dilophosaurus found Cryolophosaurus to be a derived neotheropod, close to Averostra, in a more derived position than Zupaysaurus, but less than Dilophosaurus. The following cladogram illustrates a synthesis of the relationships of the early theropod groups compiled by Hendrickx et al. in 2015. However, a 2020, a study conducted Adam Marsh and Timothy Rowe found Cryolophosaurus to be a basal Neotheropod. While it was still closer to Averostra than Coelophysoidea was, it was still more basal than Dilophosaurus.