Scientists have found a “highly preserved” skull of a species of herbivorous dinosaur in New Mexico, known for its strange adornment.
The skull belongs to the iconic dinosaur Parasaurolophus, which lived during the late Cretaceous, about 76.5 million to 73 million years ago.
Parasaurolophus were herbivorous reptiles that carried trumpet-like nasal passages in which they blew air through the so-called head tube.
This skull belonged to a certain species of the genus Parasaurolophus – Parasaurolophus cyrtocristatus.
The newly revealed specimen was said to have been about 6 meters long (6.1 meters) and about 7.5 meters high at the hip (2.3 meters) in its day.
Despite its extreme morphology, the details of the specimen show that the ridge is formed in the same way as the ridge of other duck-related dinosaurs.
Reconstruction of Parasaurolophus cyrtocristatus head life based on newly discovered remains
Parasaurolophus lived in lush, subtropical floodplains in one of the two ancient masses that once encompassed North America, separated by a 2,000-mile stretch of water.
He lived with other shellless dinosaurs, with horned dinosaurs and early tyrannosaurs, along with many modern groups of alligators, turtles and emerging plants.
“My jaw dropped when I first saw the fossil,” said Professor Terry Gates, a paleontologist at North Carolina State University.
“I have been waiting for almost 20 years to see a copy of this quality.
“Imagine your nose growing with your face, three feet behind your head, then turning to attach above your eyes.
“Parasaurolophus breathed through eight meters of pipe before oxygen ever reached the head.”
The partial skull was discovered in 2017 by Erin Spear of the Smithsonian Tropical Research Institute while exploring the lands of northwestern New Mexico, but is only now being described by scientists.
Located deep in the Bisti / De-Na-Zin wilderness 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, curator of dinosaurs at the Denver Museum of Nature and Science.
New skull of Parasaurolophus, as originally exhibited in the strong areas of New Mexico. The “refined” preservation of the new skull gives paleontologists their first opportunity to definitively identify how such a bizarre structure grew on this dinosaur.
Bisti / De-Na-Zin Desert is a 45,000-acre (18,000 ha) wilderness area located in San Juan County, 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 carved the sandstone.
Among the most recognizable dinosaurs, Parasaurolophus had an elongated, tube-like ridge on its head, containing an internal airway network.
“Over the past 100 years, exaggerated tube growth ideas have ranged from snorkels to super sniffers,” said David Evans, Temerty Department of Vertebrate Paleontology and Vice President of Natural History at the Royal Ontario Museum.
Reconstructing the life of the Parasaurolophus group in front of a tyrannosaurid in the subtropical forests of New Mexico 75 million years ago
“But after decades of study, we now believe that these ridges functioned primarily as sound resonators and visual displays used to communicate within their own species.”
Abundant bone fragments at the site indicated that much of the skeleton could have been preserved once on an ancient sandbar, but only the partial skull, part of the lower jaw, and a handful of ribs survived erosion.
“This specimen is truly remarkable in its conservation,” said Evans, who worked on the dinosaur Parasaurolophus for nearly two decades.
“He answered long-standing questions about how the ridge is built and the validity of this species. For me, this fossil is very interesting.
Today, the lands of northwestern New Mexico are dry and sparsely vegetated, a dramatic contrast to the lush floodplains of the plains preserved in their 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 Interior Seaway.
This shallow body of water stretched 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, thin land mass known as Laramidia to the west and Appalachia wider and more rectangular to the east.
Laramidia (to the west) extended from present-day Alaska to central Mexico, hosting several episodes of mountain construction in the early stages of today’s Rocky Mountain construction.
These mountain construction events have contributed to the conservation of various dinosaur ecosystems along their eastern flanks, some of the best preserved and most continuous from anywhere on Earth.
Due to various fossil discoveries, three species of Parasaurolophus are currently recognized, which are between 77 and 73.5 million years old.
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 (whose remains were found in Alberta, Canada) and P. tubicen (remains of younger rocks in New Mexico).
“The original species of parasaurolophus, P. walkeri, dates back to 1921,” said Professor Gates.
– Our parasolophone [P. cyrtocristatus] it is a different species, which was originally described in 1960 (but was 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 – overall, the newly described specimen is about 75 percent the size of the original P. walkeri found in 1921.
P. cyrtocristatus also has the most curved ridge. The other two species had long ridges with a slight curvature.
According to the researchers, the shorter and more curved ridge of P. cyrtocristatus was linked to its immaturity at death.
For decades, the Parasaurolophus family tree has placed the two longest, straight-crested species (P. walkeri in Alberta and P. tubicen in New Mexico) as the closest, despite being separated by more than 1,600 km. and 2.5 million years.
This new analysis, along with information from other Parasaurolophus discoveries in southern Utah, suggests for the first time that all southern species in New Mexico and Utah may be more closely related than they are to their northern cousin.
This is in line with patterns seen in other groups of dinosaurs of the same age, including horned dinosaurs.
“This specimen is a wonderful example of amazing creatures evolving from a single ancestor,” said Sertich.
The specimen is further detailed in a paper published in PeerJ magazine.