By Janet Tappin Coelho in Brazil
Scientists in Brazil have discovered a new species of dinosaur, believed to be the oldest long necked animal of its kind in the world that gave rise to the giant Sauropods.
Three fossilised skeletons of the prehistoric creature, named Macrocollum itaquii, were excavated from 225 million year old Triassic rocks in Agudo, in the southern state of Rio Grande do Sul.
The discovery of the well preserved remains has international importance in relation to the degree of completeness of the species and is the first muzzle to tail dinosaur found in Brazil.
The bones were unearthed and collected in early 2013 with a study of the find published last Wednesday (21) in the British scientific journal, Biology Letters.
The new dinosaur, with its elongated neck and tiny head, measured about 3.5metres (11.5ft) long and reveals important new information about the evolutionary history of the sauropods because it predates the time when these massive herbivorous animals became dominant throughout most of the planet.
Scientifically, the findings help to bridge a gap in the fossil record of dinosaurs, as there are several skeletons from earlier and more recent periods, but those with approximately 225 million years are quite rare.
Palaeontologist, Rodrigo Temp Müller of the Federal University of Santa Maria (UFSM) Palaeontology Research Centre, one of the authors of the study, said: “The rise of sauropodomorphs is still poorly understood due to the scarcity of well-preserved fossils in early Norian rocks.
“The Macrocollum itaquii is a fabulous discovery because it is a complete and exceptionally well-preserved dinosaur skeleton that helps fill the gap in (our knowledge).
“We went through comparative analysis comparing these skeletons to other sauropodomorphs in the world and found that it was a new species, based on some (distinct) characteristics.
“The fossils point to what the dinosaurs were like before they developed into the dominant creatures they became and also what characteristics led to the group’s subsequent success for millions of years.”
Details of the new dinosaur’s anatomy, which were bipeds, reveal that a small evolutionary revolution was in progress when the species arose.
The first clue lies in the cervical vertebrae, they are longer in relation to the most primitive forms of the group, such as Buriolestes schultzi, also found in Brazil.
Their neck is six times longer than their height, whereas in the latter the length of the vertebrae is only 2.5 greater than the height.
The skull is relatively small – it is only half the size of the femur – and fragile, another characteristic that would become typical of later sauropodomorphs.
The teeth indicate it had an omnivore and herbivore diet, with coarse tooth serrations, allowing it to probably complement its plant diet with small animals.
The researchers concluded that during an interval of eight million years, the herbivorous diet was improved and the sauropodomorphs grew significantly with the neck becoming proportionally longer allowing them to reach higher vegetation that that of other animals. This was what ensured the spread of the species all over the planet during the Mesozoic Era.
The overall size of the prehistoric reptiles also increased by 230 per cent as they evolved into a quadruped posture. They lost their ability to run, which was common among the more primitive dinosaurs, becoming heavy plodding weighty beings with thick, pillar like legs seen in the likes of Brachiosaurus and Apatosaurus.
The study also suggests the animals lived in herds, making it the oldest evidence of this type of behaviour in sauropodomorphs.
“The discovery of the three creatures, side by side, indicates that they died together. If they died together, they probably lived together in groups,” Müller said.
Later species of the group are believed to have put their eggs in large nests and perhaps travelled together to protect their offspring from predators.
The fossil find happened purely by accident. Müller’s uncle was working on a new build in the region when he stumbled upon the remnants embedded in a rock.
“My uncle uncovered a rock with an element that he found strange. He contacted my mother who sent me the photos and I noticed that it was a fossilised vertebra.”
A palaeontology team, formed by professionals from the UFSM and the University of São Paulo (USP), began the fieldwork in 2012 to painstakingly remove the five-ton rock with the three skeletons preserved in it.
Excavation took 20 days and after a plaster cast sealed the boulder and remains in place, the block was lifted out of its resting place at the beginning of 2013.
The name ‘Macrocollum’ (from the Greek ‘makrôs’ large and the Latin ‘collum’ neck) refers to the main characteristic of the animal and ‘itaquii’ is a tribute to José Jerundino Machado Itaqui, creator of the Centre for Palaeontological Research of the Fourth Colony (Cappa), where the fossils were found.
Two of the skeletons, Cappa 1a and 1b are almost complete and partially articulated skeletons and 1c lacks skull and cervical parts. The ancient remains have been placed on display in Cappa.