Spinosaurus: Longest Therapod?

Spinosaurus was a genus of therapod dinosaur that lived in the mid-Cretaceous Period in present-day Egypt. It is well known by the row of large vertebral spines projecting upwards from its back. Very limited fossil finds of spinosaurus have been found in Egypt and Morocco, giving scientists a general idea of how the animal would have looked.

If estimates from incomplete skeletons are correct, then spinosaurus would have surpassed even tyrannosaurus rex in terms of length. It is possible it could have attained lengths of up to 55 feet and weight nine tons. However, since most of the fossilized remains of spinosaurus at our disposal are incomplete or pulverize, it is difficult to say with any accuracy how large the animal really was. Aside from its characteristic vertebral spines, spinosaurus had a distinctly longer and narrower snout than that of other therapods like tyrannosaurus or gorgosaurus. Also, like a relative, baryonyx, spinosaurus had a large, hooked claw on each of its arms. Compared to other therapods, it had longer arms and shorter legs which suggests that it might have moved about on all fours comfortably like early archosaurs of the Triassic. It is unclear what spinosaurus ate, other than that it was flesh. The presence of the hook on the hands suggests it might have fed on fish which it would snare with this specialized appendage. The long jaws and huge size could probably also have made it either an effective hunter or scavenger. Like with most therapods, it was probably an opportunistic carnivore, killing when it could and scavenging whenever meat was available.

Scientists are unsure what kind of structure was formed by the vertebral spines. The spines are up to two meters long, which suggests that they formed a sail similar to Permian pelycosaurs such as dimetrodon. If this is the case, then spinosaurus might have used the sail for temperature regulation in the heat of the Cretaceous. However, other scientists believe that spinosaurus instead had a camel or bison-like hump that was formed out of muscle or fat. This could have served as a nutrient storehouse for when there was a shortage of food in the animal's territory. In any case, a sail or hump could have been used in courtship rituals in which the largest one would win a female. Finally it could have been used to scare predators away from kills by making the already huge spinosaurus seem larger than it really was.