Tlatolophus: Beast of the Week

 This week let's celebrate a newly described dinosaur.  Check out Tlatolophus galorum! 

Watercolor life reconstruction of Tlatolophus by Christopher DiPiazza.

Tlatolophus was a hadrosaurid ("duck-billed") dinosaur that lived in what is now Coahuila, Mexico, during the Late Cretaceous, about 73 million years ago.  It was a massive animal, measuring about 39 feet (12 meters) from beak to tail and would have eaten plants when alive.  The genus name translates to "word crest" because this dinosaur's bony head crest resembles the Aztec glyph meant to represent speech. 

Aztec word glyph which coincidentally resembles Tlatolophus' crest, just rotated. Originally from Codex Barbonicus. Image taken from Mexicolore.co.uk.

Like many large dinosaur fossils, Tlatolophus is known from incomplete remains.  That being said, the parts that were unearthed give important information about this dinosaur.  Most amazing is the fact that almost the whole skull was intact, including the elaborate crest.  (It's frustrating when a new hadrosaurid, family of dinosaurs known for having diverse crests, is discovered with no head, leaving us completely in the dark as to what it would have really looked like.)  Tlatolophus' crest was shaped like a sideways teardrop, sweeping back, behind the animals head and flaring out at the end.  The crest was hollow and connected to the animal's nasal cavity, suggesting it may have aided in producing some sort of sound in life.  

Photograph of Tlatolophus' beautifully complete skull, featured in the recent paper cited below.

Like all hadrosaurids, Tlatolophus had a beak in the front of its snout which would have had a keratin sheath growing over it in life.  This beak would have evolved for clipping off mouthfuls of vegetation which would then be shredded by the many tiny, tightly packed, teeth in the back of the mouth.  Tlatolophus also likely would have been able to walk on all fours, or on its hind legs depending on what suited it best.  It is thought that hadrosaurids most comfortably walked on all fours, but would rear up to reach higher plants while feeding, or to run faster as bipeds to escape predators.

Tlatolophus also had a long tail, proportionally longer than what is typically seen in other hadrosaurids, which made up about half the animal's total body length.  It is a total mystery why this specific hadrosaurid evolved such a long tail.  Maybe it had something to do with courtship display?  Maybe it was evolved to hit rival adults for dominance?  Long tails are also effective weapons against predators that may try to attack from behind.  A strong impact from a tail like that would surely knock a similarly-sized tyrannosaurid over, giving Tlatolophus time to escape.  We may never know for sure, however.  

It is interesting to note that paleontologists deducted, based on features of the skull, that Tlatolophus was closely related to another, more famous, hadrosaurid that also sported a striking crest, Parasaurolophus.  What's interesting is that Tlatolophus is even more closely related to Parasaurolophus, which is found in Canada and the United States, more than the hadrosaurid that it coexisted with in Mexico, called Velafrons.  It just goes to show how much different populations of closely related dinosaurs were moving around and settling in different areas over the millions of years they reigned.  

That is all for this week!  As always feel free to comment below!

References

Ramírez-Velasco, Á. A.; Aguilar, F. J.; Hernández-Rivera, R.; Gudiño Maussán, J. L.; Rodriguez, M. L.; Alvarado-Ortega, J. (2021). "Tlatolophus galorum, gen. et sp. nov., a parasaurolophini dinosaur from the upper Campanian of the Cerro del Pueblo Formation, Coahuila, northern Mexico". Cretaceous Research. in press: Article 104884.