A dazzling discovery in Northwest China of hundreds of fossilized pterosaur eggs provides a new understanding of these flying reptiles that lived next to dinosaurs, including evidence that their babies were born flightless and in need of parental care.
Scientists said on Thursday unearthed 215 eggs of Hamipterus tianshanensis, which feeds on fish, a species whose adults had a crest on an elongated skull, pointed teeth and a wingspan of more than 11 feet (3.5 meters), including 16 eggs containing partial embryonic remains.
Fossils of hundreds of adult male and female Hamipterus individuals were found along with juveniles and eggs at the site of the Xinjiang Uygur Autonomous Region, making this Cretaceous species that lived 120 million years ago perhaps the best understood pterosaur .
"We want to call this region" Pterosaur Eden ", said paleontologist Shunxing Jiang of the Verte Institute of the Chinese Academy of Sciences Paleontology and Paleoanthropology. Pterosaurs were the first flying vertebrates on Earth. Birds and bats appeared later.
So far, no pterosaur eggs have been found with embryos preserved in three dimensions. Researchers believe that up to 300 eggs may be present, some buried under exposed fossils. The embryonic bones indicated that the hind legs of a baby Hamipterus developed more rapidly than the crucial elements of the wing such as the humerus, said paleontologist Alexander Kellner of the National Museum in Rio de Janeiro.
"Some birds can fly on the same day they hatch, while others will need a long period of parental care." Our conclusion is that a baby Hamipterus can walk but can not fly, "Jiang said in an unexpected finding.
Researchers believe that these pterosaurs lived in a bustling colony near a large freshwater lake. Kellner cited evidence that the females came together to lay eggs in the nesting colonies and returned over the years to the same nesting site. They suspect that the eggs and some young and adult people were dragged from a nesting site in a storm to the lake, where they were preserved and later fossilized.
Oblong eggs, up to about 3 inches (7.2 cm) long, were flexible with a thin, hard outer layer marked by cracks and fissures that covered an inner layer of thick membrane, which resembled soft eggs of some modern snakes and lizards. There was a shortage of pterosaur eggs and embryos in the paleontological record because it is difficult for soft-shelled eggs to become fossilized. The research was published in the journal Science.