Theropoda - Wikipedia
In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by about 11,000 living species. Various synapomorphies for Theropoda have been proposed based on which taxa are included in the group.
Dinosaur - Theropods, Extinction, Fossils | Britannica
2024年12月1日 · Dilophosaurus, from the Early Jurassic Period (200 million to 176 million years ago), is considerably larger (about 4 metres total length) and is distinguished by a pair of thin bony crests running along the top of the skull. Because no other theropod had such structures, these were apparently not necessary for any physiological function and so ...
The Triassic, Jurassic, and Cretaceous Periods - ThoughtCo
2024年7月21日 · The first true prehistoric birds may have evolved by the end of the Jurassic period, though the evidence is still sparse. Most paleontologists believe that modern birds descend from the small, feathered theropods of the Cretaceous period.
Major Groups of Dinosaurs - U.S. National Park Service
2022年7月8日 · Theropods began as small hunters along the lines of Coelophysis, with long, slender bodies. Some of them evolved into large species early on, and one of these early groups eventually produced the abelisaurs, the major theropods of Southern Hemisphere continents in …
An enigmatic plant-eating theropod from the Late Jurassic period …
2015年4月27日 · A new dinosaur from the Late Jurassic period of Chile (about 150 million years ago) has been discovered and identified as a primitive kind of theropod that, unusually, was herbivore.
Allosaurus - Wikipedia
Allosaurus (/ ˌæləˈsɔːrəs /) [2][3] is an extinct genus of large carnosaurian theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic period (Kimmeridgian to late Tithonian ages). The name " Allosaurus " means "different lizard", alluding to its unique (at the time of its discovery) concave vertebrae.
A new avialan theropod from an emerging Jurassic terrestrial fauna
2023年9月6日 · Birds are descended from non-avialan theropod dinosaurs of the Late Jurassic period, but the earliest phase of this evolutionary process remains unclear owing to the exceedingly sparse and...
Dilophosaurus - Wikipedia
Dilophosaurus (/ d aɪ ˌ l oʊ f ə ˈ s ɔːr ə s,-f oʊ-/ [1] dy-LOH-fə-SOR-əs, -foh-) is a genus of theropod dinosaurs that lived in what is now North America during the Early Jurassic, about 186 million years ago.Three skeletons were discovered in northern Arizona in 1940, and the two best preserved were collected in 1942. The most complete specimen became the holotype of a new ...
Theropod | Carnivorous, Bipedal Dinosaurs | Britannica
2024年10月8日 · Theropods were the most diverse group of saurischian (“lizard-hipped”) dinosaurs, ranging from the crow-sized Microraptor to the huge Tyrannosaurus rex, which weighed six tons or more. Unlike the sauropod saurischians, all the theropods were obligate bipeds; that is, their hind legs provided support and locomotion while the short forelimbs ...
Limb bone histology of theropod dinosaurs from the Early Jurassic …
2022年12月20日 · Late Triassic and Early Jurassic theropod body fossils are relatively rare, but their ichnofossils are extremely well-represented assemblages from this time period, particularly in the Newark Supergroup of North America (e.g. Olsen et al., Citation 2002) and in the Elliot Formation of southern Africa (e.g. Sciscio et al., Citation 2016; Bordy ...