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In 1676, the first dinosaur bone was unearthed. At the time, it was believed that the massive femur belonged to a massive man, not a Megalosaur. Over 300 years have passed since then and we are still learning new facts about dinosaurs – putting together details that mirror the past.
New research published in the journal PeerJ adds to our understanding of the history of dinosaurs by focusing on another unique feature: a strange tube-shaped ridge resting on the skull of the rare Parasaurolophus cyrtocristatus. The study highlights the first discovery of this type of a Parasaurolophus cyrtocristatus skull in 97 years.
Brief history – the Parasaurolophus clade is part of a class of duck-billed dinosaurs known as hadrosaurids, which include the nasal-crested family of Lambeosaurinae. According to fan legend, the Lambeosaurus was seen in concept art for jurassic park but was deleted in the final cut of the film.
The three species known in the Parasaurolophus the family understands Parasaurolophus cyrtocristatus, Parasaurolophus tubicen, and Parasaurolophus walkeri.
What’s up – Scientists compared a newly discovered skull specimen from the Fruitland Formation, a geological site in New Mexico, to another fossil from Parasaurolophus cyrtocristatus in Utah.
Thanks to this comparison, scientists were able to better map the evolution of the Parasaurolophus species and find out how he developed such a bizarre tube-shaped head crest.
Dig into the details – The new skull specimen allowed researchers to confirm that the dramatically arched crest of the head was linked to an incredibly unique nasal passage.
“Imagine your nose growing up over your face, three feet behind your head, then turning around to fix itself above your eyes. The parasaurolophus was breathing through eight feet of pipe before the oxygen reached its head,” Terry Gates, a paleontologist from North Carolina State University, told me.
Skull Parasaurolophus cyrtocristatus.
Courtesy of the researchers.
This ridge was not just a blazing appendage. It served a crucial evolutionary purpose, according to the researchers. They believe they may have finally understood the significance of the ridge after a century of scientific debate.
“Over the past 100 years, ideas for the exaggerated tube ridge have ranged from snorkels to super sniffers,” said David Evans, Temerty Chair in Vertebrate Paleontology and Vice President of Natural History at the Royal Museum. from Ontario.
Evans added: “But after decades of study, we now believe these ridges primarily functioned as sound resonators and visual displays. used to communicate within their own species. “
The study also calls into question our understanding of the evolution of this crested dinosaur. Unlike previous studies, researchers found that the ridge of Parasaurolophus cyrtocristatus shares a lot in common with another type of hard-billed dinosaur known as the Lambeosaurus.
Beyond the ridge, the researchers found that Parasaurolophus cyrtocristatus shares a close sister relationship with another dinosaur from the same family known as the P. tubicen, explaining why fossils of both species were found in northeastern New Mexico.
While previous studies mainly focused on the dinosaur’s single crest, this study found six new traits concerning the dinosaur’s physique, such as the surprising absence of a muscle scar on the jaw and a vertically projecting squamosal – a skull bone found in amphibians, reptiles, and birds.
The researchers also wondered why, of all the bones in a dinosaur’s body, the crested skull was so well preserved among the existing bones. Parasaurolophus cyrtocristatus specimens?
They hypothesized that the development of the ridge led to the dino’s skull becoming well reinforced, ultimately preserving the specimen. So maybe we can thank Dinosaur Crest for helping scientists find the Parasaurolophus cyrtocristatus millions of years after the extinction of the dinosaurs.
On the other hand, the ridge may have been a heavy burden – literally.
“The very enlarged ridges would certainly have put relatively more pressure on the joints of the roof of the skull and the Parasaurolophuscompared to other hadrosaurid taxa. “
Why is this important – Scientists know P. cyrtocristatus for many decades, but poorly preserved specimens have prevented further study of the Parasaurolophus species.
This new study paints a more complete picture of P. cyrtocristatus, helping us to understand the evolution of this rare species.
The study states:
These two remarkably preserved new specimens provide a detailed understanding of the anatomy of the outer ridge in a species of Parasaurolophus for the first time…
And after – As with any study, this scientific discovery opens a springboard for future research.
We still do not have enough archaeological material to draw new conclusions about the strange creature that P. cyrtocristatus. More research is needed to fully understand the evolutionary function of the crest of the head.
The study states: “The skull of P. cyrtocristatus is still incompletely known, so more complete material will likely reveal new characteristics that further differentiate this species and help determine the rate of evolution of the ornamental ridge. “
Abstract: For almost 60 years, the skulls of Parasaurolophus the species were differentiated primarily on the basis of the shape of the ridge rather than the unique morphological characters of other cranial elements. To complicate matters is the fact that the ridges change shape drastically throughout ontogeny. Without a complete growth series, it has become difficult to assess the taxonomic distinction of each species through the prism of allometric growth. Parasaurolophus cyrtocristatus was found to be particularly difficult to assess due to the poorly preserved nature of the type and only the skull. A new partial skull from the Fossil Forest member of the Fruitland Formation – the same geologic unit as the type specimen – is the first opportunity to re-diagnose this species as well as redefine the genus with many new traits. An undescribed, short-crested subadult skull from the Kaiparowits Formation of Utah previously attributed to cf. P. cyrtocristatus allows detailed comparisons between the unnamed Utah taxon and material from this species at type locality. We find that several features of the squamosal, supraoccipital, and premaxilla shared between the referred skull and type skull are unique to P. cyrtocristatus (senso stricto) within the genus, regardless of the general shape of the crest. A phylogenetic analysis that includes six new traits postulates that P. cyrtocristatus and P. tubicen are sister taxa, and that the latter do not share a closest common ancestor with the P. walkeri as previously assumed. This result helps explain why both taxa are found in northeastern New Mexico, United States, and in sequential geologic units (Fruitland Formation and Kirtland Formation, respectively). In addition, the superbly preserved new skull offers the first opportunity to unequivocally identify the osteological composition of the Parasaurolophus cranial crest. Unlike previous reconstructions, the composition of the ridge in Parasaurolophus follows what is seen in other lambeosaurins such as Corythosaurus, where the dorsal process of the premaxilla dominates the ridge, the nasal forming 80% of the ventral paired tubes, and the lateral premaxillary process acting as a lateral cover between the dorsal and ventral tubes. The skull of P. cyrtocristatus is still incompletely known, so more complete material will likely reveal new characteristics that further differentiate this species and help determine the rate of evolution of the ornamental ridge.
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