Stunning fossil eggs provide insight on ancient flying reptiles

Jun 7, 2014

By Will Dunham


A spectacular fossil find in China – a prehistoric egg extravaganza from 120 million years ago – is providing unique insight into the lifestyle and gender differences of pterosaurs, the flying reptiles that lived alongside the dinosaurs.

Until now, only four pterosaur eggs had ever been found, and all were flattened during the process of fossilization.

But Chinese scientists said on Thursday they had unearthed five pterosaur eggs preserved beautifully in three dimensions at a site in northwestern China that also includes no fewer than 40 adult individuals of a newly identified species that lived in a bustling colony near a large freshwater lake.

“This is definitely the most important pterosaur site ever found,” said paleontologist Zhonghe Zhou, director of the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleoanthropology.

The creature, Hamipterus tianshanensis, had a crest atop its elongated skull, pointy teeth for catching fish and a wingspan of more than 11 feet (3.5 meters).

The five oblong eggs were “pliable” with a thin, hard outer layer marked by “cracking and crazing” covering a thick membrane inner layer, making them resemble the soft eggs of some modern snakes and lizards, said paleontologist Xiaolin Wang, another of the researchers.

“They are the best-preserved pterosaur eggs ever found,” Wang said.

The site was remarkable for what it reveals about how pterosaurs lived. At least 40 male and female individuals have been identified, and there may be hundreds in all, Wang said.

The site indicates pterosaurs lived in large colonies, in this case nesting near the lake and burying eggs in moist sand to prevent them from becoming desiccated, Wang said.

“One of the significant (aspects) of this discovery – hundreds of individuals and eggs together from one site – is that it confirmed that pterosaurs were gregarious, and the population size is surprisingly large,” Zhou said.

6 comments on “Stunning fossil eggs provide insight on ancient flying reptiles

  • 1
    Christopher says:

    Why the depiction with feathers or hair? Is there some indication that pterosaurs had them or is this just the whimsy of the artist?

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  • The particular details of this species are probably extrapolation, but pterosaur fossils in strata capable of preserving fine detail do have hair-like structures called pycnofibres:

    At least some pterosaurs had hair-like filaments known as pycnofibers on the head and body, similar to, but not homologous (sharing a common structure) with, mammalian hair. Though a fuzzy “integument” (natural covering/outer coat) “was first reported in 1831” by Goldfuss,[29] recent pterosaur finds and the technology for histological and ultraviolet examination of pterosaur specimens have provided incontrovertible proof: pterosaurs had pycnofiber coats. Pycnofibers were not true hair as seen in mammals, but a unique structure that developed a similar appearance. Although, in some cases, actinofibrils (internal structural fibers) in the wing membrane have been mistaken for pycnofibers or true hair, some fossils such as those of Sordes pilosus (which translates as “hairy demon”) and Jeholopterus ninchengensis do show the unmistakable imprints of pycnofibers on the head and body, not unlike modern-day bats, another example of convergent evolution.[21] The head-coats do not cover the pterosaur’s large jaws in many of the specimens found so far.[29]

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  • If pterosaurs evolved from ancient non-flying reptiles…. why were there still ancient non-flying reptiles around at the same time? Now there’s a question really (not) worth asking 🙂

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