Researchers of a new species of extinct reptile remains were found near Big Spring, Texas in 1940 has shown that the shapes of the body and skull of the most iconic dinosaurs arnot completely original. In a new study published in the Current Biology on Sept. 22, a group of paleontologists performed a detailed CT scan of the remains of a new species of extinct reptile called Triopticus primus, or the “First of Three Eyes” that lived about 230 million years ago before the era of the dinosaurs. The creature was characterized by a large natural pit at the top of its head that looked like an extra eye. It also featured a very thick skull roof similar to those of the distantly related pachycephalosaur dinosaurs that emerged more than 100 million years later.
Many of the other extinct animals that were found with Triopticus in the Otis Chalk fauna were also found to have body parts that resembled those of dinosaurs. Among these features are those that were similar to the toothless beaks of ornithomimids, the long snouts of the Spinosaurus and the armor plates of the ankylosaurus. The Triopticus provides an example of evolutionary convergence, a common evolutionary phenomenon that occurs when two distantly related species independently evolve similar body shape and appearance likely as a result of having to adapt to similar environments. “We introduce a new Triassic stem archosaur that is unexpectedly and remarkably convergent with the ‘dome-headed’ pachycephalosaur dinosaurs that lived over 100 million years later,” the researchers wrote in their study.
“Surprisingly, numerous additional taxa in the same assemblage (the Otis Chalk assemblage from the Dockum Group of Texas) demonstrate the early acquisition of morphological novelties that were later convergently evolved by post-Triassic dinosaurs.”
The latest finding offered evidence of convergence across a considerable length of time and among a diverse group of dinosaurs and reptiles from the Triassic and Jurassic periods. The Triopticus in particular exemplifies body-shape convergence as the shape of its skull appear to have been copied by distantly related dome-headed dinosaurs that emerged after more than 100 million years. “It is amazing to think that many of the iconic dinosaur features that we know and love, such as long snouts, toothless beaks, armor plates and thickened dome skulls, were arrived at completely independently up to 100 million years earlier in these distant reptilian cousins,” said University of Chicago evolutionary biologist Katharine Criswell.
That is because the third pit in the top of its head lends the appearance of a third eye being there. A very thick skull roof is present too. In this it resembles its distant cousins in the future, the pachycephalosaur dinosaurs. They lived a 100 million years later. Many of the other creatures, whose bones were unearthed with the Triopticus, resembled the later dinosaurs. This greatly surprised the scientists. Triopticus is an example of a rare convergence between the relatives of dinosaurs and crocodylians and later dinosaurs. The commonality is somewhat of a shock for paleontologists.
The bodily shapes of dinosaurs actually developed a long time ago in the Triassic Period. That is 225 million years ago. Convergence is a central theme in evolutionary biology. A bird’s wing and bat’s wing are two examples of convergence. While both are functional as flight agents, they actually evolved differently and separately.
Many other reptiles found alongside Triopticus show characteristics of later dinosaurs. These include the long snouts of Spinosaurus, the toothless beaks of ornithomimids and the armor plates of ankylosaurs. This occurrence of convergence is an extremely rare example of such a vast cornucopia of life forms being centralized along one single pattern of design options. The view afforded from the fossil record shows an amazing array of body forms that belied the convergence between them.
The Triopticus is unique since its skull shape was copied by its much later relative which was a dome-skulled dinosaur. This species occurred a 100 million years later. Dinosaurs are reptiles. Towards the end of the Permian Period that is 250 million years ago a mass extinction took place. After this reptiles exploded in their numbers. They came in all sorts of sizes and shapes. Mimicry in body shape was something that took place here as the later dinosaurs showed in their physiognomies.