Researchers are reporting the finding of the first three-dimensionly preserved eggs of pterosaurs, flying reptiles with wingspans up to half the length of a tennis court.
The eggs, found in China, turned up among at least dozens of pterosaur fossils, representing a new species called Hamipterus tianshanensis, scientists reported.
The animals lived together in colonies, according to the researchers, who presented their work in the journal Current Biology on June 5.
“Five eggs are three-dimensionly preserved, and some are really complete,” said Xiaolin Wang of the Chinese Academy of Sciences, who was involved with the research. It was most exciting to find many male and female pterosaurs and their eggs preserved together, he added.
The pterosaur fossil record has generally been poor, with little information about their populations, the researchers say. Only four isolated and flattened pterosaur eggs were known to science before now.
The resting place of the pterosaurs now described was uncovered in 2005 in the Turpan-Hami Basin, south of the Tian Shan Mountains in Xinjiang, northwestern China. The fossil-rich area is thought to possibly harbor thousands of bones. Wang said sediments in the area suggest that the pterosaurs died in a large storm about 120 million years ago in the Early Cretaceous period.
The researchers examined the largely intact pterosaur egg specimens to find that they were pliable, with a thin eggshell outside and a soft, thick membrane inside, similar to the eggs of some modern-day snakes. The researchers’ observations of 40 male and female individuals suggested differences between the sexes in the size, shape, and robustness of their head crests.
The combination of many pterosaurs and eggs strongly indicates the presence of a nesting site nearby and indicates that this species developed gregarious behavior, the researchers said. Hamipterusmost likely buried their eggs in sand along the shore of an ancient lake to prevent them from drying out, they added. While the new fossils are thought to shed light on their reproductive strategy, development, and behavior, there’s still much left to learn about them.
“Sites like the one reported here provide further evidence regarding the behavior and biology of this amazing group of flying reptiles that has no parallel in modern time,” the researchers wrote.
Source : http://www.world-science.net