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Description

Tylosaurus proriger was a large mosasaur that swam where today is the central USA and Canada, which were under a shallow sea referred as Western Interior Seaway during the late Cretaceous Period. Reaching more than 14 meters long, T. proriger fossils are well documented, often being found with stomach content fossilized aswell, revealing that it's diet as an apex predator included fish, sharks, other sea reptiles, birds, and other creatures smaller than itself. This species had a reinforced rostrum, with a toothless tip, capable of sustaining blows, suggesting this tip was used as a weapon for hunting and/or territorial combat. Although speculative, territorialism is probable due to the nature of apex predators and availability of prey, but please keep in mind that this assertion was not based on fossil evidence like the rest of the description. The coloration was based on Lidgren et.al. 2014 paper "Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles" (linked below), which as described in the title, exposes the fossil evidence for a darker coloration in the sea lizards. Sperm whales were used as a reference, but sperm whales do not rely on speed bursts to hit their prey as they hunt for squid in areas with low visibility, and for a predator like Tylosaurus proriger, I believe counter shading to a logical adaptation for this shallow water hunter. The orca-like look was somewhat an accident, but I think the pattern looks good - Paleoart also has "art" in the name - and functional. Tylosaurs used their fins and mainly their strong tails to propel themselves in the water, and although the tail lacks bone structures for two lobes, there are fossils of mosasaurs with the mold of the upper lobe aswell as reconstructions portraying the upper lobe. As for my personal opinion, I find the upper lobe to be quite logic; Buoyancy is crucial for sea creatures, and animals that lack swim bladders have to rely on alternative methods, like lungs for air breathing animals, and big livers / large upper lobes for sharks. Shark's lobes propel them upwards, so following a similar logic, would be really annoying for a creature that nosebutts other animals to have to compensate the downwards propelling with it's fins and lungs. With a less extreme ration between the lobes, the precision would increase, but this is, once again, personal opinion - I might not be aware of the specific mechanics of downward swimming, but with my current knowledge and research it was what made most sense to me. But then again, many reconstructions depict the presence of a large upper lobe, and here I based my Tylosaur on Fabio Romero's reconstruction which will be linked below!

About the art, I feel exhilarated as this is my first time trying to draw a marine reptile and I think the result was not horrible! The reason I didn't draw a fish was that the theme of this week's art challenge for the Uni's art group was "Squamata paleoart", and my mind automatically drifted to the large mosasaur lizards of the past. I am biased towards the sea, what can I do? I had very little time to do this, and also the reason I've been posting less here is because of that; I'm at the end of a semester, and I have one nasty test coming up next week, aswell as one scientific communication post for another class, and an animated video too, all of this for next wednesday at most! I like to take my time doing the research (specially with Paleo which is not my area) and drawing the environment and details, but this one was a rushdown - hence why it's on a lower resolution! It's still good in my eyes, so here it is!

www.nature.com/articles/nature…

twitter.com/FabioAleRomero/sta…

Description

Tylosaurus proriger was a large mosasaur that swam where today is the central USA and Canada, which were under a shallow sea referred as Western Interior Seaway during the late Cretaceous Period. Reaching more than 14 meters long, T. proriger fossils are well documented, often being found with stomach content fossilized aswell, revealing that it's diet as an apex predator included fish, sharks, other sea reptiles, birds, and other creatures smaller than itself. This species had a reinforced rostrum, with a toothless tip, capable of sustaining blows, suggesting this tip was used as a weapon for hunting and/or territorial combat. Although speculative, territorialism is probable due to the nature of apex predators and availability of prey, but please keep in mind that this assertion was not based on fossil evidence like the rest of the description. The coloration was based on Lidgren et.al. 2014 paper "Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles" (linked below), which as described in the title, exposes the fossil evidence for a darker coloration in the sea lizards. Sperm whales were used as a reference, but sperm whales do not rely on speed bursts to hit their prey as they hunt for squid in areas with low visibility, and for a predator like Tylosaurus proriger, I believe counter shading to a logical adaptation for this shallow water hunter. The orca-like look was somewhat an accident, but I think the pattern looks good - Paleoart also has "art" in the name - and functional. Tylosaurs used their fins and mainly their strong tails to propel themselves in the water, and although the tail lacks bone structures for two lobes, there are fossils of mosasaurs with the mold of the upper lobe aswell as reconstructions portraying the upper lobe. As for my personal opinion, I find the upper lobe to be quite logic; Buoyancy is crucial for sea creatures, and animals that lack swim bladders have to rely on alternative methods, like lungs for air breathing animals, and big livers / large upper lobes for sharks. Shark's lobes propel them upwards, so following a similar logic, would be really annoying for a creature that nosebutts other animals to have to compensate the downwards propelling with it's fins and lungs. With a less extreme ration between the lobes, the precision would increase, but this is, once again, personal opinion - I might not be aware of the specific mechanics of downward swimming, but with my current knowledge and research it was what made most sense to me. But then again, many reconstructions depict the presence of a large upper lobe, and here I based my Tylosaur on Fabio Romero's reconstruction which will be linked below!

About the art, I feel exhilarated as this is my first time trying to draw a marine reptile and I think the result was not horrible! The reason I didn't draw a fish was that the theme of this week's art challenge for the Uni's art group was "Squamata paleoart", and my mind automatically drifted to the large mosasaur lizards of the past. I am biased towards the sea, what can I do? I had very little time to do this, and also the reason I've been posting less here is because of that; I'm at the end of a semester, and I have one nasty test coming up next week, aswell as one scientific communication post for another class, and an animated video too, all of this for next wednesday at most! I like to take my time doing the research (specially with Paleo which is not my area) and drawing the environment and details, but this one was a rushdown - hence why it's on a lower resolution! It's still good in my eyes, so here it is!

www.nature.com/articles/nature…

twitter.com/FabioAleRomero/sta…