Spinosaurids: what is it?

Spinosaurus is one of dinosaurs best known to the general public. He is part of the clade spinosaurids which includes carnivorous predators with multiple shapes and an intriguing dorsal veil.

Spinosaurus is the common name of a carnivorous dinosaur well known to sci-fi lovers. However, this term does not designate a species in particular, but summarizes in a stereotype all the diversity of the representatives of the group of spinosaurids. Spinosaurids populated the Gondwana and Laurasia in Jurassic and at Cretaceous. The first specimen of this group, which belonged to the species Spinosaurus aegyptiacuswas described in 1915 in Egypt.

Among the dinosaurs, spinosaurids belong to the clade of saurischians, which includes species whose pubis is forward-facing, unlike the ornithischian clade. Within saurischians, spinosaurids are part of the theropod clade which included the species of carnivorous dinosaurs. The morphological characteristics of spinosaurids include a maxillary long and jaws ending in a rosette. Spinosaurids also exhibit very elongated neural spines which allow for the presence of a dorsal sail.

A diversity of spinosaurs

The spinosaurids of course include the genera Spinosaurus and Baryonyx but also those, less known, Ichthyovenator, Suchomimus and Irritator. The diversity of shapes among spinosaurids includes for example the shape and amplitude of the dorsal, reduced and posterior sail in Baryonyxreduced but long in Suchomimus and enlarged in Spinosaurus.

This could have helped with thermoregulation, during swimming or signaled its presence in the water. The diet of spinosaurids was estimated from the shape of their skull and their teeth as well as by the presence of innervation channels similar to those of crocodilians current. So they were probably piscivorous but could feed on other prey because remains of iguanodontidae have been discovered in thestomach of one Baryonyx as well as a spinosaurid tooth found in pterosaur vertebrae. Spinosaurids were probably mostly bipedal and the density of the long bones of Spinosaurus suggests a semi-aquatic lifestyle.