Stokesosaurus (meaning "Stokes' lizard") is a genus of small (around 3 to 4 meters (10 to 13 ft) in length), carnivorous early tyrannosauroid theropod dinosaurs from the late Jurassic period of Utah, United States[1] and Guimarota, Portugal.

[11] More fragmentary remains possibly referable to Stokesosaurus have been recovered from stratigraphic zone 2 of the Morrison Formation, dated to the late Kimmeridgian age, about 152 million years ago.

Benson and Stephen Brusatte concluded that not a single bone had been justifiably referred to Stokesosaurus, and that not even the paratype could be safely assigned, leaving the holotype ilium as the only known fossil of the taxon.

In addition, many traits initially believed to unite Stokesosaurus clevelandi and Juratyrant langhami under one genus[6] could not be conclusively disproven to exist on other tyrannosauroids.

[14] Below is a 2013 cladogram by Loewen et al. that places Stokesosaurus and Juratyrant as derived members of Proceratosauridae, due to sharing with Sinotyrannus a narrow preacetabular notch.

[16] Proceratosaurus bradleyi Kileskus aristotocus Guanlong wucaii Sinotyrannus kazuoensis Juratyrant langhami Stokesosaurus clevelandi Dilong paradoxus Eotyrannus lengi Bagaraatan ostromi Raptorex kriegsteini Dryptosaurus aquilunguis Alectrosaurus olseni Xiongguanlong baimoensis Appalachiosaurus montgomeriensis Alioramus altai Alioramus remotus Tyrannosauridae However, a 2016 analysis utilizing both parsimonious and Bayesian phylogeny placed Stokesosaurus and Juratyrant as tyrannosauroids slightly more advanced than Proceratosauridae and Dilong.

The Morrison Basin where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west.

In 1877 this formation became the center of the Bone Wars, a fossil-collecting rivalry between early paleontologists Othniel Charles Marsh and Edward Drinker Cope.

The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs such as Camarasaurus, Barosaurus, Diplodocus, Apatosaurus and Brachiosaurus.

[22] Other animals that shared this paleoenvironment included bivalves, snails, ray-finned fishes, frogs, salamanders, turtles, sphenodonts, lizards, terrestrial and aquatic crocodylomorphs, and several species of pterosaur.