New research shows that plesiosaurs, marine reptiles known for their long necks, developed this unique feature within five million years, about 250 million years ago.
Plesiosaurs developed their distinctive long necks quickly, evolving over five million years, and a recent study revealed the entry of a new ancestor, Chosaurus xiangensis.
Research shows that plesiosaurs developed their characteristic long necks in a very short time.
These long necks are believed to be used to chase fast-moving fish, and evolved rapidly over five million years, around 250 million years ago.
The results were recently published in the journal BMC ecology and evolution, and carried out by scientists in China and England, showed that A Classify Known as pachypleurosaur, it elongated its neck mainly by adding new vertebrae. This type has 25 vertebrae, some late Cretaceous Plesiosaurs such as Elasmosaurus had as many as 72 vertebrae, and their necks were five times the length of their bodies.
New assets and discoveries
These creatures first appeared in the early Triassic, just four million years after the mass extinction at the end of the Permian period, which led to the disappearance of nearly 90% of Earth’s species. This period was characterized by rapid transformation following these cataclysmic events.
In the study, the researchers described a new ancestor of short-necked plesiosaurs called plesiosaurs Chosaurus xiangensis From the Early Triassic, Hubei Province, China. The neck began to lengthen, but the body was only half as long, compared to 80% or more in its later relatives.
The image shows the rapid development rate and samples. Research shows that plesiosaurs, marine reptiles known for their long necks, developed this unique feature within five million years, about 250 million years ago. Credit: Chi-Ling Liu
“We were lucky enough to find two complete skeletons of this new animal,” said Qi Ling Liu of China University of Geosciences in Wuhan, who led the project. “It was small, less than half a meter long, but close to the origins of an important group of marine reptiles called Sauropterygia.
“We have a new reptile, Chausaurus, is a pachypleurosaur, one of a group of small marine predators that was very important in the Triassic period. At first I wasn’t sure if this was a pachypleurosaur, because the neck looked very short.
Context and comparison
“The fossil comes from the Nanchang-Yuan’an fauna in Hubei,” said Dr Li Tian from China University of Geosciences in Wuhan, who co-led the project. “It has been studied very intensively in recent years as one of the oldest groups of marine reptiles from the Triassic period. We have good quality radiometric dates that show the animal dates back 248 million years.”
Associate Professor Michael Benton from the University of Bristol’s UCLA School of Geosciences said: “The mass extinction at the end of the Permian period was the largest mass extinction ever recorded, with only one in twenty species surviving.
“The Early Triassic was a period of recovery and marine reptiles evolved very quickly at that time, and most of them were predators of shrimp, fish and other sea creatures. They appeared soon after the Extinction, so we know their rate of change was enormous. rapidly in the New World after the Crisis.
Pashepleurosaurus “They basically elongated their necks by adding new vertebrae,” said Associate Supervisor Professor Qinglong of the China Geological Survey Center in Wuhan.
“usually, Vertebrates Like reptiles, mammals (us) have seven vertebrae in their necks. Chausaurus already had 17, while later pachypleurosaurs had 25. Some late Cretaceous plesiosaurs such as Osmosaurus He is even 72 years old, and his neck is five times the length of his body. With its many vertebrae, this long neck must have been very snake-like and probably struck the neck to catch suspicious prey while keeping its body still.
Diverse evolutionary tactics
Dr Tom Stubbs, from the Open University in the UK, added: “Not all long-necked animals do the same. For example, giraffes have seven standard cervical vertebrae, but each cervical vertebra is so long that it can reach the tallest trees. Flamingos also have long necks so they can reach the water to find food, due to their long legs, and they have up to twenty additional vertebrae, but each vertebra is also long.
Dr Ben Moon, also from the University of Bristol, added: “Our study shows that pachypleurosaurs doubled their necks within five million years, and then the rate of increase slowed.” It is assumed that they have reached the ideal neck length for their lifestyle.
“We think that, as small predators, they probably only feed on shrimp and small fish, so their ability to sneak into small groups, then float through the water, and throw their heads behind fast-swimming prey is a great survival tool. However there may be an additional cost to having a longer neck, so I chose a length that is the same as the torso length.
Reference: “Rapid neck elongation in Sauropterygia (Reptilia: Diapsida) detected by a new basal pachypleurosaur from Lower Triassic China” by Qi-Ling Liu, Long Cheng, Thomas L. Stubbs, Benjamin C. Moon, Michael J. Benton and Li Tian , 31 August 2023, Available here. Ecology and Evolution of BMC.
doi: 10.1186/s12862-023-02150-s
2023-09-10 03:29:44
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