Dr Adam Yates describes the dinosaur, Antetonitrus ingenipes in a paper published by the Royal Society this month. The paper is co-authored by Professor James Kitching, the palaeontologist who unearthed the fossil bones in South Africa.
The new dinosaur is the oldest known member of the sauropods, the family of gigantic, long-necked, herbivorous dinosaurs that includes Diplodocus, Apatosaurus, and Brachiosaurus. Its genus name (Antetonitrus) means 'Before the Thunder', and its species name (ingenipes) means 'Massive Feet'.
It lived 210-215 million years ago and was the biggest land animal of its time. It measured about ten metres from its nose to the tip of its long tail, and would have weighed in the region of 1.8 tonnes.
Dr Yates was the first to recognise that the fossil bones unearthed by Professor Kitching in the Ladybrand District of the Free State in the early 1980s were those of a very early sauropod dinosaur and not a prosauropod (meaning 'Before the Lizard Feet') as they had been previously classified.
Dr Yates said: "I first saw the bones in the Bernard Price Institute collection when I came to South Africa in 2001 as part of a research project for the University of Bristol. I took notes, sketches and photographs of the fossils back to England for study and, when I returned to South Africa the following year, took the opportunity to examine the fossils further.
"By the end of 2002, I was convinced the skeletal remains were those of a sauropod dinsaur that had lived in the late Triassic Period, about 210-215 million years ago. This was very exciting because the only early sauropod known was from the very end of the Triassic, right on the boundary of the Jurassic period. This meant the South African dinsoaur was millions of years older, from the very beginning of the dinosaur age. In other words, these fossils could teach us things about the earliest dinosaurs that we had never known before."
Professor Michael Benton, Head of Bristol University's Department of Earth Sciences, said: "The first dinosaurs were quite small - about the size of a ten-year-old child - and they ran about on their hind legs. This new dinosaur shows the first move back on to all fours.
"It's also very important to see that Antetonitrus had a mobile clawed thumb on its front foot that could grasp as well as swipe at any predators. Only later did sauropods completely lose this function, and concentrate on using their front feet solely for weight support."
Dr Yates will be visiting the site of the discovery this week and is hoping to find out more about how his dinosaur died. He said: "Perhaps we might even be lucky enough to find some more fossils in the area. It's obviously an important site that could shed more light on the first of the giant dinosaurs."
'The earliest known sauropod dinosaur and the first steps towards sauropod locomotion' by Dr AM Yates and Dr JW Kitching, is published by the Royal Society this month.