Oldest Reptile Mummy Sheds Light on the Ancient Art of Breathing
For us to exist on Earth today, vertebrate animals had to transition from their aquatic world to a terrestrial lifestyle, which is believed to have happened around 390 to 365 million years ago when “fish” like Tiktaalik waddled out of the sea.
Then these terrestrial pioneers had to adapt to obtain oxygen in a new environment. Unlike the ocean, where they pumped their mouths to draw oxygenated water onto the gills or absorbed oxygen through the surface of the skin, land animals had to evolve respiratory systems that recruited the ribs to expand and compress the chest cavity.
A recent study by paleontologists at the University of Toronto describes a fossilized reptile, Captorhinuswith the oldest known example of a vertebrate’s rib cage structured to power inhalation and exhalation, in what is known as “rib breathing”. The remains were discovered in a cave in Oklahoma.
“We propose that the system found in Captorhinus “This efficient breathing apparatus is important for their more active, energetic and competitive lifestyle compared to that of their amphibian counterparts.”
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The mummified reptile remains, dating to around 289 million years ago, were extraordinarily well preserved, including not only their bones but also the skin, cartilage and other soft tissues around their respiratory systems.
The study authors hypothesize that the reptiles died in a cave where they were buried in fine clay sediments, after which they were exposed to mummifying liquids such as mineral-rich groundwater and hydrocarbons from an oil seep. Even some of their protein biomolecules have been preserved, pushing back the date of preserved animal proteins in the fossil record by 100 million years.
From these fragile remains, researchers used scanned and geochemical analyzes to reconstruct the Captorhinus respiratory system, revealing a ribbed method of breathing similar to that of modern lizards. The structure of the shoulder girdle, allowing lateral movements during walking, also resembled that of modern lizards.
“The mummified Captorhinus “This is one of the most important early amniote fossils in the world,” explained Ethan Mooney, co-author of the study. “It provided an unprecedented window into the appearance, lifestyles and evolution of early reptiles, greatly expanding our understanding of this crucial episode in amniote evolution.”
It certainly breathes new life into our old ways of thinking from when vertebrates helped bring life beyond the sea.
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Main image: Internet Archive Book Images / Wikimedia Commons
