Fossil of a Galesaurus, a cynodont closely related
Picture: Supplied
T-Rex may have been king‚ but a very mammal-like adaption allowed our ancestors to outlive this beast and that was hair.
New research‚ that involved scanning the fossil remains of mammal-like reptiles found in the Karoo‚ has found that they may have evolved hair and whiskers.
The whiskers‚ it is believed‚ could have been used as a sensory tool to operate at night well before the Mesozoic era when dinosaurs became the dominant species.
“Whiskers are an amazing sensory tool to have when you are nocturnal and the evolution of whiskers possibly assisted in the survival of the therapsids – and more specifically the probainognathians – which eventually evolved into mammals as we know them today‚” Dr Julien Benoit of Wits University said in a statement.
These mammal-like animals were therapsids that once dominated terrestrial ecosystems across the globe‚ but it is South Africa that has the best fossil record of this group of creatures.
While no therapsid fossil has been found with evidence of hair‚ through the use of CT scans and three-dimensional modelling‚ Benoit and his colleagues were able to find neural structures that suggested the presence of hair.
They found that the maxillary canal of therapsids‚ a bony tube in the snout of the animal that houses the trigeminal nerve‚ is shorter in therapsids than in reptiles.
The trigeminal nerve is the nerve that gives sensitivity to the snout of the animal‚ and is connected to whiskers.
According to Benoit‚ research into mutant mice has revealed that the gene MSX2 controls the development of mammary glands and the maintenance of body hairs.
He believes that this gene underwent significant change in the period 240-246 million years ago and triggered the evolution of many typical mammalian traits including hair and whiskers.
“Our research has shown that these features of mammals were already present in advanced therapsids‚ prior to the appearance of mammals‚” Benoit said.
“It also has implications for understanding how mammals survived the domination of dinosaurs during the Mesozoic period and the subsequent evolutionary success of mammals.”
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– TMG Digital/The Times
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