"high-spine lizard" (Gr. 'acro' - high; 'akanthos' - spine)
; 110 mya
Location: North America
, by Stovall & Langston
40 ft. (13 m)
16 ft. (5 m) at the hip
3.5 to 5 tons (3,200 to 4,500 kilos)
one full skeleton, and many fragments
Acrocanthosaurus was named for its high spines along its neck and back, which could extend about 2 to 3 feet high. These were smaller than the sails on such later dinosaurs as spinosaurus. Scientists are unsure of what these spines were used for, but one of the big theories is that they were anchors for strong jaw muscles. There is evidence that it hunted large sauropods, and its jaws and arms were definitely up to the task. Also, footprints support this evidence. However, as with tyrannosaurus, some scientists believe it was a scavenger.
Its feet were smaller than many dinosaurs its size, but that's because it lived in a relatively drier climate than others. Its arms, however, were much larger than the tiny arms associated with many Cretaceous theropods. The teeth were relatively thin and curved, which meant that they were better used for tearing flesh off of dead prey rather than killing (It used its strong neck for this). It belonged to the same family of dinosaurs as allosaurus, which was a very successful family. The only complete skeleton was found in Akota county, Oklahoma by love & Hall in 1983 and nicknamed 'Fran'.