Ostafrikasaurus

Type Species: Ostafrikasaurus crassiserratus

Classification: Dinosauria - Saurischia - Theropoda - Carnosauria – Megalosauroidea – Megalosauria – Spinosauridae – Baryonychinae

Time Period: Late Jurassic 

Location: Africa

Diet: Carnivore

Ostafrikasaurus is known only by a single tooth, and yet that lone tooth changed a theropod lineage forever. The single took, discovered in the Tendaguru Formation of Tanzania, is different from those of most theropods and more aligned with the unique teeth of the spinosaurs. Because all other spinosaurs date from the Cretaceous Period, the presence of a spinosaur tooth in the Tendaguru Formation pushed their genesis back into the Late Jurassic. Whereas most theropods have recurved, blade-like teeth with serrations for cutting through meat, spinosaur teeth were straighter, more conical, and had few if any serrations. Ostafrikasaurus’ teeth had a few serrations, indicating that these serrations were lost as the spinosaur family evolved. This may be because spinosaurs embraced a pescetarian (fish-hunting) lifestyle: conical, spear-like teeth are seen in modern fish-hunting gharials, as their design lends them to piercing and maintaining grip on slippery aquatic prey that can be swallowed whole rather than torn apart. The estimated 28-foot-long Ostafrikasaurus likely hunted in the coastal environments of northern Africa, hunting fish and even snagging the occasional pterosaur or two. Though its skull hasn’t been found, it’s likely that it had the crocodile-like snouts of its descendants. However, given its early placement in the spinosaurid family, it may have resembled non-spinosaurid theropods, as well. Until more remains are found, we can only speculate as to what it looked like fleshed-out. 

The spinosaurs are divided into two subfamilies: Baryonychinae and Spinosaurinae. Baryonchines have slightly curved, finely-serrated teeth with more oval cross-sections, whereas spinosaurines have straight, fluted teeth with reduced or absent serrations. Given the fact that Ostafrikasaurus’ teeth are more in line with the former, it’s been placed with the baryonychines and likely represents a primitive form of that subfamily.