Caitlin O'Kane
Tue, December 21, 2021
A well-preserved dinosaur embryo has been found inside a fossilized egg. The fossilized dinosaur embryo came from Ganzhou, Jiangxi Province in southern China and was acquired by researchers in 2000.
Researchers at Yingliang Group, a company that mines stones, suspected it contained egg fossils, but put it in storage for 10 years, according to a news release. When construction began on Yingliang Stone Natural History Museum, boxes of unearthed fossils were sorted through.
"Museum staff identified them as dinosaur eggs and saw some bones on the broken cross section of one of the eggs," Lida Xing of China University of Geosciences, Beijing, said in a news release. A embryo was found hidden within, which they named "Baby Yingliang."
The embryo is that of the bird-like oviraptorosaurs, part of the theropod group. Theropod means "beast foot," but theropod feet usually resembled those of birds. Birds are descended from one lineage of small theropods.
Reconstruction of a close-to-hatching oviraptorosaur egg.
Credit: Lida Xing/iScience
In studying the embryo, researchers found the dinosaur took on a distinctive tucking posture before hatching, which had been considered unique to birds. The study is published in the iScience journal.
Researchers say this behavior may have evolved through non-avian theropods. "Most known non-avian dinosaur embryos are incomplete with skeletons disarticulated," said Waisum Maof the University of Birmingham, U.K. "We were surprised to see this embryo beautifully preserved inside a dinosaur egg, lying in a bird-like posture. This posture had not been recognized in non-avian dinosaurs before."
In studying the embryo, researchers found the dinosaur took on a distinctive tucking posture before hatching, which had been considered unique to birds. The study is published in the iScience journal.
Researchers say this behavior may have evolved through non-avian theropods. "Most known non-avian dinosaur embryos are incomplete with skeletons disarticulated," said Waisum Maof the University of Birmingham, U.K. "We were surprised to see this embryo beautifully preserved inside a dinosaur egg, lying in a bird-like posture. This posture had not been recognized in non-avian dinosaurs before."
The oviraptorosaur embryo
While fossilized dinosaur eggs have been found during the last 100 years, discovering a well-preserved embryo is very rare, the researchers said in the release.
The embryo's posture was not previously seen in non-avian dinosaur, which is "especially notable because it's reminiscent of a late-stage modern bird embryo."
The researchers will continue to study the rare specimen in even more depth. They will attempt to image its internal anatomy. Some of its body parts are still covered in rocks. Their findings can also be used in more studies of fossil embryos.
A perfectly preserved dinosaur egg highlights link to modern birds
Tom Metcalfe
Tue, December 21, 2021
A 66-million-year-old fossil of a complete baby dinosaur in its egg, apparently just a few days before it would hatch, shows the remarkable similarities between theropod dinosaurs and the birds they would evolve into, according to a study published Tuesday.
The fossilized bones of the embryo, named “Baby Yingliang” after the museum in southern China where it was discovered, can be seen curled-up inside its 6-inch elongated eggshell and looking almost exactly like a modern bird at that stage, although it has tiny arms and claws rather than wings.
Fion Waisum Ma, a paleontologist at the University of Birmingham in the United Kingdom, said the head is particularly striking in its similarity to the head of a newly hatched bird — a resemblance heightened by a beak that was a feature of this dinosaur species, called an oviraptorosaur. Ma is one of the lead authors of the fossil study published in the journal iScience. Scientists from China, Canada and elsewhere in the U.K. were also involved.
Oviraptorosaurs, a type of theropod dinosaur with hollow bones and three-toed limbs, were very close to the dinosaur ancestry that evolved into modern birds. As well as beaks, they had feathers on their arms. They could not fly, but there’s evidence they spread the feathers out above their nests to keep the eggs beneath them warm, said John Nudds, a paleontologist at the University of Manchester in the U.K, who was not involved in the study.
Embryonic dinosaur fossils are extremely rare — paleontologists have only found them at about half a dozen sites. And this is the first time any have shown signs of a distinctive posture known as “tucking” — with the head under the right arm — although some other dinosaur embryos have shown distinct “egg teeth” that they may have used to break out of their shells, Nudds said.
Life reconstruction of a close-to-hatching oviraptorosaur dinosaur embryo, based on the new specimen ‘Baby Yingliang’. (Courtesy Lida Xing)
Ma said that until now the tucking posture had been seen only in birds.
“Some embryos are quite well preserved, but they don’t show this posture,” she said. “And some are very fragmentary, so it is difficult to see their posture clearly.”
Baby birds adopt the posture, with their head “tucked” under their right wing, in the egg just a few days before they hatch; and embryos that fail to get it right are seldom able to hatch properly.
Ma said tucking seems to help baby birds make their first cracks in the eggshell by restricting the movement of their head.
“It’s easier to stabilize the beak and to direct it to the same place when they try to break the eggshell,” she said.
The researchers suggest the tucking posture evolved because oviraptorosaurs had a hard shell, like those of birds, instead of a soft shell, like those of turtles — an early form of shell that was still common about 70 million years ago among dinosaurs like the sheep-sized protoceratops.
Scientists think hard egg shells gave better protection from the environment than soft egg shells, and so oviraptorosaurs and related dinosaur species may have evolved the tucking posture to break through their harder eggshells, Ma said.
Baby Yingliang was in a cache of fossils that were delivered in 2000 to the Yingliang Stone Nature History Museum in the Chinese city of Nan’an, possibly after they had been found at a construction site in the nearby city of Ganzhou.
But it wasn’t until 2015 that one of the museum staff examined the fossil egg and noticed that what appeared to be bones could be seen in a fracture.
The fossilized egg has now been scientifically analyzed, and the fossil split so that the complete skeleton of the embryo can be seen curled up in its shell.
The study suggests the fossil is 66 million to 72 million years old. The baby dinosaur would’ve been about 10 inches from beak to tail when it was hatched, and might have grown to more than 6 feet long as an adult.
Image: Baby Yingliang dinosaur embryo (Lida Xing)
Modern chicken eggs take about 21 days to hatch, although they are much smaller than this dinosaur, and scientists don’t know how long Baby Yingliang had been developing in its egg before it was fossilized. It seemed to be about to hatch within a few days, Ma said.
Many dinosaur experts have hailed the fossil as one of the best-preserved embryos they have ever seen. But some are not certain, however, that what the researchers have interpreted as a tucking posture in the embryo is actually that.
“This is an interesting discovery, but I am skeptical about the ‘tucking’ behavior as it is primarily based on a single specimen,” said Shundong Bi of the Indiana University of Pennsylvania. “I think more evidence is needed.”
Bi was not involved in the latest research but studied the fossilized remains of a different oviraptorosaur crouching above a clutch of 24 eggs, some of which contained embryos.
The interpretation of the tucking posture depended on the dinosaur egg containing a pocket of air, like the eggs of birds. But that could not be seen in this fossil and had not been seen in other dinosaur eggs, Bi said in an email.
Tom Metcalfe
Tue, December 21, 2021
A 66-million-year-old fossil of a complete baby dinosaur in its egg, apparently just a few days before it would hatch, shows the remarkable similarities between theropod dinosaurs and the birds they would evolve into, according to a study published Tuesday.
The fossilized bones of the embryo, named “Baby Yingliang” after the museum in southern China where it was discovered, can be seen curled-up inside its 6-inch elongated eggshell and looking almost exactly like a modern bird at that stage, although it has tiny arms and claws rather than wings.
Fion Waisum Ma, a paleontologist at the University of Birmingham in the United Kingdom, said the head is particularly striking in its similarity to the head of a newly hatched bird — a resemblance heightened by a beak that was a feature of this dinosaur species, called an oviraptorosaur. Ma is one of the lead authors of the fossil study published in the journal iScience. Scientists from China, Canada and elsewhere in the U.K. were also involved.
Oviraptorosaurs, a type of theropod dinosaur with hollow bones and three-toed limbs, were very close to the dinosaur ancestry that evolved into modern birds. As well as beaks, they had feathers on their arms. They could not fly, but there’s evidence they spread the feathers out above their nests to keep the eggs beneath them warm, said John Nudds, a paleontologist at the University of Manchester in the U.K, who was not involved in the study.
Embryonic dinosaur fossils are extremely rare — paleontologists have only found them at about half a dozen sites. And this is the first time any have shown signs of a distinctive posture known as “tucking” — with the head under the right arm — although some other dinosaur embryos have shown distinct “egg teeth” that they may have used to break out of their shells, Nudds said.
Life reconstruction of a close-to-hatching oviraptorosaur dinosaur embryo, based on the new specimen ‘Baby Yingliang’. (Courtesy Lida Xing)
Ma said that until now the tucking posture had been seen only in birds.
“Some embryos are quite well preserved, but they don’t show this posture,” she said. “And some are very fragmentary, so it is difficult to see their posture clearly.”
Baby birds adopt the posture, with their head “tucked” under their right wing, in the egg just a few days before they hatch; and embryos that fail to get it right are seldom able to hatch properly.
Ma said tucking seems to help baby birds make their first cracks in the eggshell by restricting the movement of their head.
“It’s easier to stabilize the beak and to direct it to the same place when they try to break the eggshell,” she said.
The researchers suggest the tucking posture evolved because oviraptorosaurs had a hard shell, like those of birds, instead of a soft shell, like those of turtles — an early form of shell that was still common about 70 million years ago among dinosaurs like the sheep-sized protoceratops.
Scientists think hard egg shells gave better protection from the environment than soft egg shells, and so oviraptorosaurs and related dinosaur species may have evolved the tucking posture to break through their harder eggshells, Ma said.
Baby Yingliang was in a cache of fossils that were delivered in 2000 to the Yingliang Stone Nature History Museum in the Chinese city of Nan’an, possibly after they had been found at a construction site in the nearby city of Ganzhou.
But it wasn’t until 2015 that one of the museum staff examined the fossil egg and noticed that what appeared to be bones could be seen in a fracture.
The fossilized egg has now been scientifically analyzed, and the fossil split so that the complete skeleton of the embryo can be seen curled up in its shell.
The study suggests the fossil is 66 million to 72 million years old. The baby dinosaur would’ve been about 10 inches from beak to tail when it was hatched, and might have grown to more than 6 feet long as an adult.
Image: Baby Yingliang dinosaur embryo (Lida Xing)
Modern chicken eggs take about 21 days to hatch, although they are much smaller than this dinosaur, and scientists don’t know how long Baby Yingliang had been developing in its egg before it was fossilized. It seemed to be about to hatch within a few days, Ma said.
Many dinosaur experts have hailed the fossil as one of the best-preserved embryos they have ever seen. But some are not certain, however, that what the researchers have interpreted as a tucking posture in the embryo is actually that.
“This is an interesting discovery, but I am skeptical about the ‘tucking’ behavior as it is primarily based on a single specimen,” said Shundong Bi of the Indiana University of Pennsylvania. “I think more evidence is needed.”
Bi was not involved in the latest research but studied the fossilized remains of a different oviraptorosaur crouching above a clutch of 24 eggs, some of which contained embryos.
The interpretation of the tucking posture depended on the dinosaur egg containing a pocket of air, like the eggs of birds. But that could not be seen in this fossil and had not been seen in other dinosaur eggs, Bi said in an email.
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