Throughout time, life for Africa’s organisms has always been a fight of the survival of the fittest.
This was especially true of a distant, pre-mammalian reptile known as the therapsid Euchambersia, said Julien Benoit, a researcher at the Bernard Price Institute for Palaeontological Research at Wits University.
Fending off gigantic predators like sabre-toothed carnivores to survive led the small, dog-sized creature to turn its saliva into a deadly venomous cocktail.
Benoit said the Euchambersia lived in the Karoo, near Colesberg, 260 million years ago. It measured between 40cm and 50cm long and lived well before dinosaurs existed.
To survive the rough conditions of the South African environment, he said, it developed a deep and circular fossa, just behind its canine teeth in the upper jaw, in which a deadly venomous cocktail was produced, and delivered directly into the mouth through a fine network of bony grooves and canals.
“This is the first evidence of the oldest venomous vertebrate ever found,” he said. “Today, snakes are notorious for their venomous bite, but their fossil record vanishes in the depth of geological times at about 167 million years ago. So, at 260 million years ago, the Euchambersia evolved venom more than a 100 million years before the very first snake was even born,” he said.
As venom glands don’t fossilise, Benoit and his colleagues at Wits University, in association with the Natural History Museum of London, used CT scanning and 3D imagery techniques to analyse the only two fossilised skulls of the Euchambersia found.
The team discovered stunning anatomical adaptations compatible with venom production. Their results were published in the open access journal, PlosOne, early this month.
“First, a wide, deep and circular fossa - a space in the skull - to accommodate a venom gland was present on the upper jaw and was connected to the canine and the mouth by a fine network of bony grooves and canals,” said Benoit.
The team also discovered previously undescribed teeth hidden in the vicinity of the bones and rock.
“We found two incisors with preserved crowns and a pair of large canines that all had a sharp ridge. Such a ridged dentition would have helped the injection of venom inside a prey,” he said.
Snakes such as vipers or cobras inject their prey with venom through needle-like grooves in their teeth. However, the Euchambersia’s venom flowed directly into its mouth and was passively introduced into its victim through ridges on the outside of its canine teeth.
“Euchambersia could have used its venom for protection or hunting. Most venomous species today use their venom for hunting, so I would rather go for this option,” Benoit concluded. What is interesting about the Euchambersia is that it is related to early mammals, not snakes.
More venom-producing mammals are discovered every year, including shrews and primates like the Loris of South-East Asia.
Benoit said researchers believe that mammals that lived millions of years ago used to be venomous, but lost this ability over time. The first Euchambersia fossil was found in 1932 and the second in 1966.
The two fossils were both found on the farm Van Wyk’s Fontein, near Colesberg in the Northern Cape.
Although they were found more than 34 years apart from each other, for millions of years they were lying metres apart.