Scientists have found in New Mexico a “exquisitely preserved” skull of a species of herbivorous dinosaur, known for its strange head ornament.
The skull belongs to the iconic tube-crested parasaurolophus dinosaur, which lived during the Late Cretaceous period, about 76.5 million to 73 million years ago.
Parasaurolophus were herbivorous reptiles that had trumpet-like nasal passages to which they blew air through the so-called head tube.
This particular skull belonged to a particular species of the genus Parasaurolophus: Parasaurolophus cyrtocristatus.
The newly revealed specimen would have been 6.1 meters tall and 2.3 meters high at the hip (2.3 meters) in its day.
Despite its extreme morphology, the details of the specimen show that the crest is formed in the same way as the crests of other duck-related dinosaurs.
Vital reconstruction of the head of Parasaurolophus cyrtocristatus from recently discovered remains
Parasaurolophus lived in lush subtropical floodplains in one of the two ancient land masses that once comprised North America, separated by a 2,000-mile-long stretch of water.
He lived with other duckless dinosaurs, with horns and early tyrannosaurs, alongside many emerging and modern groups of alligators, turtles and plants.
“My jaw dropped when I first saw the fossil,” said Professor Terry Gates, a paleontologist at North Carolina State University.
‘I’ve been waiting almost 20 years to see a copy of this quality.
Imagine that your nose makes your face grow, three meters behind your head, and then you turn to look over your eyes.
“Parasaurolophus breathed through eight feet of pipe before oxygen ever reached his head.”
The partial skull was discovered in 2017 by Erin Spear of the Smithsonian Tropical Research Institute while exploring the wetlands of northwestern New Mexico, but they are only now being described by scientists.
Located at the bottom of the Bisti / De-Na-Zin Desert of New Mexico, only a small portion of the skull was visible on a steep sandstone slope.
“The preservation of this new skull is spectacular, finally revealing in detail the bones that make up the crest of this amazing dinosaur known to almost every child obsessed with dinosaurs,” said Joe Sertich, dinosaur curator at the Denver Museum of Nature and Science.
New skull of Parasaurolophus originally exposed in the bated lands of New Mexico. The “exquisite” preservation of the new skull gives paleontologists the first opportunity to definitively identify how such a strange structure grew in this dinosaur.
The Bisti / De-Na-Zin Wilderness is a wild area of 45,000 acres (18,000 ha) located in San Juan County in the United States state of New Mexico.
“This only reinforces the importance of protecting our public lands for scientific discoveries.”
Sertich-led museum volunteers were surprised to find the ridge intact as they carefully chiseled the sandstone specimen.
Among the most recognizable dinosaurs, Parasaurolophus had an elongated, tube-like crest on its head that contained an internal network of airways.
“For the past 100 years, ideas for the purpose of the exaggerated tube ridge have ranged from snorkels to super sniffers,” said David Evans, Temerty Professor of Vertebrate Paleontology and Vice President of Natural History at the Royal Ontario Museum .
Vital reconstruction of the group Parasaurolophus faced by a tyrannosaurus in the subtropical forests of New Mexico 75 million years ago
“But after decades of study, we now think these ridges functioned primarily as sound resonators and visual displays that were used to communicate within their own species.”
Abundant bone fragments at the site indicated that much of the skeleton may have once been preserved in an ancient sandbar, but only the partial skull, part of the lower jaw, and a handful of ribs survived erosion.
“This specimen is really remarkable in its conservation,” said Evans, who has worked on the dinosaur Parasaurolophus for nearly two decades.
“He has answered long-standing questions about how the ridge is built and about the validity of this particular species. For me, this fossil is very exciting.”
Today, the bada lands of northwestern New Mexico are dry and sparsely vegetated, a spectacular contrast to the lush floodplains of the lowlands preserved in its rocks that would have been the natural habitat of Parasaurolophus.
Seventy-five million years ago, when Parasaurolophus lived in the region, North America was divided into two land masses by the Western Inland Seaway.
This shallow body of water stretches from the Gulf of Mexico to the Arctic Ocean and divided the continent into two land masses: East America or Appalachia and West America or Laramidia for several million years. .
The creation of the seaway led to the formation of a long, slender land mass known as Laramidia in the west and the wider, more rectangular Appalachia in the east.
Laramidia (in the west) stretched from present-day Alaska to central Mexico, hosting multiple episodes of mountain construction in the early stages of construction of the present-day Rocky Mountains.
These mountain-building events helped preserve various dinosaur ecosystems along its eastern flanks, some of the best-preserved and continuous on Earth.
Thanks to several fossil finds, three species of Parasaurolophus are currently recognized, ranging from 77 to 73.5 million years.
The new skull belongs to P. cyrtocristatus, previously known from a single specimen collected in the same region of New Mexico in 1923 by the legendary American fossil hunter Charles H. Sternberg.
The other two recognized species of Parasaurolophus are P. walkeri (the remains of which were found in Alberta, Canada) and P. tubicen (remains of younger rocks in New Mexico).
“The original species of parasaurolophus, P. walkeri, is from 1921,” Professor Gates said.
‘Our Parasaurolophus [P. cyrtocristatus] it is a different species, originally described in 1960 (but found many years before it was named).
“So this is the first P. cyrtocristatus to be found and described in 60 years.”
P. cyrtocristatus was the smallest of the three species; in general, the newly described specimen is about 75% the size of the original P. walkeri found in 1921.
P. cyrtocristatus also has the most curved crest. The other two species had long ridges with only a slight curvature.
According to the researchers, the shorter, curved crest of P. cyrtocristatus may have been related to its immaturity at death.
For decades, the Parasaurolophus family tree ranked the two longest, straight-crested species (P. walkeri from Alberta and P. tubicen from New Mexico) as the most closely related, despite being separated by more than 1,600 km and 2.5 km. million years.
This new analysis, along with information from other discoveries of Parasaurolophus in southern Utah, suggests for the first time that all species in southern New Mexico and Utah may be more related than their northern cousin.
This fits the patterns observed in other groups of dinosaurs of the same age, including horned dinosaurs.
“This specimen is a wonderful example of amazing creatures that evolve from a single ancestor,” Sertich said.
The issue is further detailed in an article published in PeerJ magazine.