Fossilized dinosaur nest discovered in Mongolia, paleontologists announce.
Paleοпtolοgοs eпcueпtraп пidο fossilized from diпοsauriο eп Mοпgοlia
An international team of paleontologists from Belgium, France and Mongolia has unearthed an exceptional block of perinatal (baby) specimens of the giant hadrosaur dinosaur Saurolophus angustirostris, with associated eggshell fragments, in an area called the Dragon’s Tomb.
Perinatal specimens of Saurolophus angustirostris: the bones on the right side of the block show some degree of articulation, while the bones on the left side are disarticulated. Image credit: Dewaele L et al.
The Dragon’s Tomb dinosaur locality was discovered in 1947 in the Nemegt Formation of the Gobi desert in Mongolia.
The bone bed from this site has produced numerous articulated skeletons of Saurolophus angustirostris. This dinosaur is particularly abundant throughout the Nemegt Formation, comprising about 20 percent of all vertebrate fossils found.
In a new report published in the journal PLoS ONE, paleontologists describe three or four perinatal Saurolophus angustirostris specimens and two associated eggshell fragments.
The young dinosaurs were probably part of a nest originally located on a river bank. The skull length of these Saurolophus angustirostris was around 5 percent of that of the largest known S. angustirostris specimens, indicating that these specimens were in the early stages of development.
“The perinatal bones already resembled the features of Saurolophus angustirostris, including the upturned snout,” the paleontologists explained.
“The specimens did not yet have the characteristic cranial crest on the top of the head and the areas of the skull, the cervical neural arches, were not yet fused, suggesting that they may be in the early stages of S. angustirostris development. ”
“The underdeveloped crest in Saurolophus angustirostris infants provides evidence for ontogenetic crest growth within the Saurolophini tribe,” said lead author Dr. Leonard Dewaele, from the University of Ghent and the Royal Belgian Institute of Science. natural.
“The Saurolophini are the only Saurolophinae to have supracranial ridges as adults.”
Saurolophus angustirostris adult. Image credit: L. Xing & Y. Liu, doi: 10.1371/journal.pone.0031295.g013.
Paleontologists can’t say whether the Saurolophus angustirostris babies were still in the eggs or had just hatched when they died, but they were apparently already dead and partially decomposed when they were buried by river sediments during the wet summer season.
Fossilized eggshell fragments associated with perinatal individuals closely resemble those found in relatives of Saurolophus angustirostris in Mongolia.
The team suggests that these specimens may fill a gap in our knowledge about the development of Saurolophus angustirostris.