Johannesburg, Feb 14 (IANS) A reptile related to early mammals was the first to produce venom in order to survive the rough conditions offered by the deadly South African environment 260 million years ago -- some 100 million years before the very first snake was even born -- a study says.

Computerised tomography (CT) scans of fossils of the dog-sized reptile, Therapsid Euchambersia, showed anatomical features, designed for venom production, according to the study published in the journal, PlosOne.

"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, " said Julien Benoit from University of the Witwatersrand in South Africa.

As venom glands do not 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 ever found, and discovered stunning anatomical adaptions that are compatible with venom production. 

"This is the first evidence of the oldest venomous vertebrate ever found, and what is even more surprising is that it is not in a species that we expected it to be," Benoit said.

The first Euchambersia fossil was found in 1932, and the second in 1966. According to measurements of the two fossils, the Euchambersia was a small dog-like pre-mammalian reptile that grew between 40 and 50 cm long.

"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," Benoit said. 

"Moreover, we discovered previously undescribed teeth hidden in the vicinity of the bones and rock: 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," Benoit explained.