Tyrannosaurs

Tyrannosauroids Temporal range: Middle Jurassic–Late Cretaceous, 165–66 Ma PreЄ Є O S D C P T J K Pg N
Replica skeletons of Yutyrannus huali
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
Clade:	Tyrannoraptora
Superfamily:	†Tyrannosauroidea Osborn, 1906
Type species
†Tyrannosaurus rex Osborn, 1905
Subgroups
†Alectrosaurus †Appalachiosaurus †Aviatyrannis †Bagaraatan? †Calamosaurus? †Dryptosaurus †Eotyrannus †Labocania †Santanaraptor †Timimus? †Timurlengia †Xiongguanlong †Coeluridae †Proceratosauridae †Tyrannosauridae
Synonyms
Deinodontoidea Cope, 1866 Coeluroidea Marsh, 1881

Deinodontoidea Cope, 1866
Coeluroidea Marsh, 1881

Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period. By the end of the Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic Tyrannosaurus itself. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe, Asia, South America and Australia.

Tyrannosauroids were bipedal carnivores, as were most theropods, and were characterized by numerous skeletal features, especially of the skull and pelvis. Early in their existence, tyrannosauroids were small predators with long, three-fingered forelimbs. Late Cretaceous genera became much larger, including some of the largest land-based predators ever to exist, but most of these later genera had proportionately small forelimbs with only two digits. Primitive feathers have been identified in fossils of two species, and may have been present in other tyrannosauroids as well. Prominent bony crests in a variety of shapes and sizes on the skulls of many tyrannosauroids may have served display functions.