Utahraptor ostrommaysorum, Skull Pteranodon It was heavy and supported

It was heavy and supported by the last seven tail vertebrae

estimated at lengths of 30 feet and weighing up to 6 tones

being some 2/3 the size of the others

It is likely that mosasaurs became extinct along with the dinosaurs during the extinction event at the end of the Cretaceous Period

It was a large animal

Utahraptor ostrommaysorum, Skull Pteranodon It was heavy and supportedUtahraptor (meaning "Utah's predator" is a genus of theropod dinosaurs. It contains a single species, Utahraptor ostrommaysorum, which is the largest known member of the family Dromaeosauridae. Fossil specimens date to the upper Barremian stage of the early Cretaceous period (in rock strata dated to 126 2. 5 million years ago). The holotype specimen of Utahraptor is fragmentary, consisting of skull fragments, a tibia, claws and some caudal (tail)