Tyrannosauroidea means "Tyrant lizard forms", and is a clade of coelurosaurian theropod dinosaurs that includes also the family Tyrannosauridae.
They lived on the Laurasian supercontinent from the Jurassic era, until the end of the Cretaceous era, becoming slowly the dominating species wherever they lived, eliminating even Allosaurs and Megalosaurs.Members of the Tyrannosauroidea clade have been found as fossils in North America, Europe, Asia, and maybe even Australia and South America.
Tyrannosauroids were mostly small-to medium-sized animals in their first 80 million years, becoming in their final 20 million years the biggest terrestrial predators to ever have walked the Earth.
Early tyrannosauroids were small animals, with longer and thinner skulls (in proportion), longer forelimbs, with three-fingered hands, and also thinner bodies. In contrast, later tyrannosauroids were huge animals (the biggest of them being the Tyrannosaurus rex , at 40-46 ft or 12-14 meters long and wheighing between 7-9 tons). Their skulls were thicker and stronger with a more powerful bite-force, shorter forelimbs with only two fingers, and were generally more robust.
Feathers and CrestsEditEarly tyrannosauroids had proto-feathers, as this was found on the tiny tyrant Dilong in 2004. It is considered that they, being smaller animals, used proto-feathers as a heat regulator. A discovery in 2012 suggested that the large tyrant Yutyrannus also sported proto-feathers. Early tyrannosauroids had also crests, especially the Proceratosauridae family, that made from crests their distinctive mark. They had big crests, and used them mostly for display.
The integument of later tyrannosauroids is heavily debated; though skin impressions of small, hexagonal scales are only known to be found on the tail and feet of these giants. Many members of the Tyrannosauridae family had a proeminent horn in front of each eye on the lacrimal bone, as showed in Gorgosaurus, Albertosaurus, and Daspletosaurus. The lacrimal bone is absent only in Tarbosaurus and Tyrannosaurus, that instead had a crescent-shaped crest behind each eye on the postorbital bone.
- Appalachiosaurus montgomeriensis;
- Aviatyrannis jurassica;
- Bistahieversor sealeyi;
- Dilong paradoxus;
- Dryptosaurus aquilunguis;
- Calamosaurus foxi;
- Eotyrannus lengi;
- Juratyrant langhami;
- Labocamia anomala;
- Stokesosaurus clevelandi;
- Tanycolagreus topwilsoni
- Xiongguanlong baimoensis;
- Yutyrannus huali;
- Guanlong wucaii;
- Kileskus aristotocus;
- Proceratosaurus bradleyi;
- Sinotyrannus kazuoensis;
- Iliosuchus incognitus (too fragmentary);
- Bagarataan ostromi (might be a maniraptoran);
- Chingkankousaurs fragilis
- Diplotomodon horrificus (may be synonymous with either Dryptosaurus species);
- Dryptosaurus macropus (too fragmentary);
- Dryptosaurus falculus (too fragmentary);
- Dryptosaurus hazenianus (too fragmentary);
- Raptorex kriegsteini (might be a juvenile Tarbosaurus instead).
- Shanshanosaurus huoyanshanensis (once a seperate species, but now considered a juvinile, most likely Tarbosaurus)