February 23, 2012 Despite belonging to one of the most famous
dinosaur groups of all time, few people have heard of
Stokesosaurus clevelandi. This predator, named in 1974 by
paleontologist James Madsen, Jr., was a tyrannosauroid dinosaur
that roamed North America tens of millions of years before
Tyrannosaurus rex. The bones of Stokesosaurus were initially
discovered in the fossil-rich Cleveland-Lloyd Dinosaur quarry in
eastern Utah. Although dominated by the remains of at least 46
Allosaurus, rarer traces of other theropod dinosaurs have come
out of the quarry. (The mid-size carnivore Marshosaurus and
possibly a distinct species of Ceratosaurus have also been
recognized from bones found here.) In the case of Stokesosaurus,
Madsen had identified two portions of the hip and a piece of the
upper jaw, the premaxilla, as belonging to this small theropod.
The complete animal probably didn’t stretch longer than 12 feet
from nose to tail. While Madsen was tentative about this
conclusion, the diminutive predator seeme