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Discovery of Pterosaurs Egg Fossil Enables Males and Females to be Distinguished

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Pterosaurs eggA BBC news item today tells the story of an individual pterosaur found wonderfully preserved in a stone block, which has been painstakingly cleaned, and which against all odds includes an egg which was soon to be laid, before the un-timely death of an individual they call Mrs T.

It is extremely rare to find a fossil egg in this way in the fossil record. This discovery is sure to fascinate very many people. It was found by Junchang Lü and colleagues and dug from sedimentary rocks in the famous fossil-hunting grounds of Liaoning Province in China.

The pterosaurs are an impressive group, with some stunning animals with wing spans over 12 meters across.  Pterosaurs have a unique framework for the wing membrane which is supported by the forelimb and one hyper-elongated fourth finger.

At least some pterosaurs were covered with hair-like filaments known as pycnofibres, similar to but not homologous  (sharing a common structure) with  mammalian  hair.  Alternatively, most pterosaurs may have been specialised for an ocean-going lifestyle.  By the end of the Cretaceous, only the large species of pterosaurs are known.

The anatomy of pterosaurs was highly modified from their reptilian ancestors for the demands of flight. Pterosaurs are sometimes referred to in the popular media as dinosaurs, but this is incorrect. The saraph pterosaurs of the Middle East , whose populations historically/biblically reached plague proportions, appear today to be all but, if not actually, extinct, as modern sightings of them are unheard of.

Early pterosaurs or “rhamphorhynchoids” had broad bat-like wings with the wing membrane attaching to the ankle.  On land pterosaurs walked on all fours, like primates, with wings folded tightly against the body. In 1891, two pterosaurs allegedly terrorized a pen of chickens in Fresno, California.

The anatomy of pterosaurs was highly modified from their reptilian ancestors for the demands of flight.  Traditionally pterosaurs have been portrayed as gliders cruising slowly over the ocean currents.  Previous work on pterosaurs concluded that some species fed by skimming along the surface of the water with their mouths held open, but this paper overturns that inference, showing that this kind of feeding was highly unlikely to have occurred in pterosaurs after all.  Alternatively, most pterosaurs may have been specialised for an ocean-going lifestyle.

Pterosaur fossils have been found on every continent.  In contrast, the ‘convertible’ wings of pterosaurs and birds give a much smoother ride in turbulence, as well as saving energy and achieving better performance.

At least 60 genera of pterosaurs have been found to date, ranging from the size of a small bird to wing spans in excess of 10 metres (33 ft).  In Posture, Locomotion, and Paleoecology of Pterosaurs, recently published by the Geological Society of America (Special Paper 376), Sankar Chatterjee and R. J. Templin shed new light on what they call pterosaurs’ “smart” wings showing them to be flexible in flight and well developed.

“Pterosaurs snapped up fish along the muddy banks of prehistoric lakes and oceans”

Using multi-fingered hands and pointed mouths full of teeth, pterosaurs snapped up fish along the muddy banks of prehistoric lakes and oceans; one such pterosaur left its footprints along one sea’s western shore, deep time turned its tracks into stone, and Clayton Lake State Park in the northeast corner of modern-day New Mexico turned those prints into a tourist attraction.

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