The Spinosauridae: Gigantic Bipedal "Crocosaurs" Who Ruled the Seas

Image comparing the sizes of members in the Spinosauridae family

What would your first thought be if I told you that roughly 100 million years ago, there once lived a clade of dinosaurs unlike no other. Large bipedal sometimes even quadrupedal carnivores, the biggest being longer and heavier than the tyrant lizard himself. Equipped with a set of serrated crocodilian-like teeth, their jaws were slender and narrow, in the shape of a canoe, slowly thinning at the tip. Attached to their shoulders, stocky arms capable of piercing through the ancient fish they one feasted on. Their back, boasting a giant sail, with vertebrate reaching up to 6 feet in height.

You might believe "impossible", such a creature had to be fictional, no different from the monsters and mythical creatures that appeared in your dreams as a child. 

Yet the spinosaurids were indeed real, in fact, fossils have been uncovered across the globe, including South America, Africa, Asia and Europe. 

These dinosaurs were a class of semi-aquatic theropods, hosting the largest land-bearing predator ever discovered, the infamous Spinosaurus, reaching a length of almost 60 feet. The diet of these creatures was relatively diverse compared to most theropods. Fossils uncovered of two different spinosaurids, the Irritator, native to South America, and the Baryonyx, native to Europe, showed that these creatures had a semi-pescatarian diet, with the other half including young/small dinosaurs such as juvenile hadrosaurs or even pterosaurs.

Portrait of Spinosaurus based on latest fossil findings

However, the average bite force of these "crocosaurs" was much less in comparison to other theropods, often comparable to modern-day alligators. Spinosaurus itself, having a bite force half as much as other theropods of similar size. The Spinosauridae most likely finished off larger prey by using their claws as the main weapon instead. Utilizing their jaws to hold prey in place whilst they finished the job.

Another unique aspect of this species was their conical teeth, which were extremely sharp and pointy, perfect for puncturing and impaling, rather than tearing apart. Combined with the conical teeth, two large canines poked out of the spinosaurids spoon-shaped jaws, along with a couple others farther in the back. Truly reflecting the varied diet of this family and how opportunistic they were as theropods.

A popular theory amongst the paleontologists was that some Genuses had the ability to purposefully "unhinge" their jaws, allowing for a wider playing field when it came to catching both aquatic and terrestrial food. Yet there is still much to be discovered regarding the Spinosauridae and their weird, watery habits.

For further information visit the articles 10 Facts About Spinosaurus and Spinosauridae

Image showcasing the spinosaurids' conical teeth

    

Figure depicting the "unhinging" action of Irritator's jaws