Researchers digitally reconstructed the skull of the 330-million-year-old species Crassigyrinus scoticus, revealing a shape similar to that of a modern crocodile, rather than the long skull previously thought. The discovery sheds light on the behavior of this ancient predator that lived in coal swamps and likely hunted like modern crocodiles.
A relative of one of the first animals to land, scientists have been trying to understand this 330-million-year-old species for nearly a century. However, this was particularly difficult, as all known fossils of Carboniferous predators were highly fragmented.
Advances in computed tomography and 3D imaging mean that a research team has now been able to put the pieces together for the first time and reveal what Krassygirin’s skull would look like. . Dr Laura Porro from University College London (UCL), lead author of the new study, said: “This animal was previously reconstructed with a very elongated moray eel-like skull based on the flattened type specimen from Edinburgh.”
“However, when I tried to simulate this shape with a digital CT surface, it didn’t work. It was impossible for an animal with such a wide palate and such a narrow skull roof to have such a head.”
The article was published on May 2. Journal of Vertebrate Paleontology Dedicated to co-author Professor Jenny Cluck, a pioneering paleontologist who revolutionized our understanding of early tetrapod evolution and died in 2020.
“It’s sad to see this article finally published,” says Laura. “Jenny Clack worked on this as a postdoctoral researcher and I’m glad she was able to see the final reconstruction. Krassigirina. He was very inspiring and I look forward to working with him for many more years.”
How to restore a flattened fossil
Crassigyrinus — quadrupedal bodied animals, a group of four-legged animals that were among the first to make the transition from water to land. However, unlike their relatives, Crassigyrinus it was an aquatic animal because its ancestors had turned from land to water or never landed. Instead, it lived in the coal swamps found in what is now Scotland and parts of North America, creating the conditions for its posthumous preservation.
“These animals were preserved in fine-grained rocks that provided excellent contrast during CT,” explains Laura. “Unfortunately, it didn’t provide a lot of structural integrity, so when more material builds up on the top Crassigyrinuscrushed the fossils.”
This means that some known specimens are fairly complete, but all are broken and deformed. The splitting, flattening, and stacking of bones have led to various reconstructions in the past.
The team used CT scans of four samples to try to reconstruct this squashed sample. Crassigyrinus, three of which are in the museum. Among these fossils were all the bones of the skull, which allowed them to begin the reconstruction of the tetrapod skull.
“Once we identified all the bones, it was a bit like a 3D puzzle,” says Laura. “I usually start with the remnants of the meninges, because that would be the core of the skull, and then I would fuse the palate around it.”
“This gives me a foundation from which I can begin to build upwards using areas of overlapping bone known as sutures, which give clues to how the bones of the skull come together. Because the bones weren’t bent, they were broken, we were able to reconstruct the specimen with reasonable confidence.
The resulting smaller skull shape is consistent with a recent reassessment of the rest of the body. crasihyrinus, found that this is a relatively straight animal with very short limbs. Together, these reconstructions may reveal more about how he lived. Krassigirin.
What was discovered about Crassigyrinus ?
With a name meaning “fat tadpole”, Crassigyrinus does not cause fear. However, it would have been a formidable predator in its time.
“For life Crassigyrinus It would have been about two or three meters long, which was pretty big for the time,” says Laura. “It probably behaved similarly to modern crocodiles, hiding below the water’s surface and using its powerful bite to snatch prey.”
shape of the skull Krassigirina It contains a series of protrusions that can help strengthen the skull and spread the bite force between the many teeth.
Any prey that comes his way will also have to contend with a number of special senses that assist him. Crassigyrinus follow them These included large eyes to see in dim coal swamps and lateral lines to detect vibrations in water. The mysterious slit in the front of his nose could also be a sign that he had other senses.
Many early tetrapods had midline cavities in front of their snout, but Crassigyrinus they are much larger and have smoothly chiseled edges,” explains Laura. “The nostrils were in a different place, so there was a lot of speculation as to what the hole might have been.”
One possibility, like some live fish, Crassigyrinus It may have a rostral organ that helps it sense electric fields. It may also have a Jacobson’s organ found in animals such as snakes, which helps detect various chemicals.
“Unfortunately, we can’t be sure what happened in this rift, because nothing there has survived and nothing living today is so closely related to this rift. Krassigirin“It’s clear that these animals have very well developed senses, so it makes sense that they have another sense organ in front of their noses.”
Now that the skull has been reconstructed, the researchers are testing it in a series of biomechanical simulations to see what it can do.
Source: Port Altele
