Spinosaurus; enigmatic giant:
Tyrannosaurus rex, long considered to be the heavyweight champion of the predatory dinosaurs has recently been forced to yield that title to Giganotosaurus carolinii, the scourge of South America 100 million years ago. While Giganotosaurus still holds the crown for terrestrial terrors the record for overall length and mass seems to belong at least for now, to Spinosaurus aegyptiacus.
While Giganotosaurus and Spinosaurus were contemporaries, each living in the mid Cretaceous period the current fossil record negates the possibility of a face to face encounter. Spinosaurus flourished in North and Sub-Saharan Africa while all known Giganotosaurus remains have been collected in what is now Argentina.
Spinosaurus was first discovered in 1912 by German paleontologist Ernst Stromer while on an expedition to Egypt. The partial skeleton, identified as a juvenile was already some 46 feet in length and in life might have weighed in at seven and one half tons. Stromer recovered additional fossils in 1934. Additional findings have lead to assumptions that a truly large Spinosaur would approach 60 feet in total length and tip the scales at well over 10 tons.
Spinosaurus is determined to be a theropod dinosaur, meaning that it employed a primarily two legged gait while on land. It had a relatively slender but long – nearly 6 feet – crocodilian style skull containing strong, conical teeth. Unusual for this type of dinosaur Spinosaurus – the name means “spiny lizard” – had a row of spines over five feet in length projecting from the center of its back. Some scientists theorize that these spines may have supported a hump of fat and muscle, similar to those of a modern bison but the consensus seems to be in favor of a sail type structure. This structure would be similar in appearance to that of the pelycosaur Dimetrodon although the actual make up would have been more robust.
Land versus water:
No one doubts that Spinosaurus could move about well enough on land using a primarily two legged gait while possibly dropping into a four legged stance now and then. While land bound it could have scavenged slain dinosaur carcasses as well as ambushed juvenile iguanodons and sauropods – there is even some evidence that an occasional pterodon may have become a snack for a hungry Spinosaur.
Recent thinking has placed Spinosaurus more in the water than on land functioning as a part time ambush style predator at the waters edge, much like a modern crocodile. Scales have been found mingled with Spinosaur bones and the habitat where these fossils were found was an enormous mangrove swamp at the time of the creatures’ death. It may well be that Spinosaurus was primarily a piscivore or fish eater; the fishes of the mid cretaceous were certainly large enough to sustain such a feeding style.
If this supposition is correct Spinosaurus would have found itself in direct competition with another gigantic apex predator; Sarcosuchus imperator. Sarcosuchus was merely the largest crocodile yet discovered at a recorded length of 40 feet and an estimated maximum length of 60 feet. Conflict between these two titans must have occurred at least occasionally.
Whatever the outcome, neither Spinosaurus nor Sarcosuchus outlived the mid Cretaceous, succumbing to climate changes as the environment gradually became drier.
Definitive answers about exactly which role this titanic predator primarily filled will have to wait for the discovery of a complete skeleton, so that the exact relationship of the limbs to the body may be determined. It would also be helpful if a fine sediment find could reveal the actual purpose of the spinal spikes; did they, for example, support a sail or a hump? If a sail, was it for thermal regulation or courtship display? If a hump, then what was the mass of this gigantic creature?
At the rate that new finds are being made in Africa one can reasonably expect some answers to these questions sooner rather than later.
Just for fun:
Tyrannosaurus Rex vs. Spinosaurus, courtesy of Jurassic Park and You Tube: