Paper at [ http://www.nature.com/srep/2014/140904/srep06196/full/srep06196.html ].
"A newly identified species of supermassive dinosaur might have been one of the largest creatures ever to walk on land, suggests a study published on 4 September in Scientific Reports.
Well-preserved bones of the species, Dreadnoughtus schrani
, were excavated in southern Argentina between 2005–09. The animal is a titanosaur, one in a typically hefty subgroup of the long-necked, plant-eating dinosaurs known as sauropods.
The genus name Dreadnoughtus, from the Old English meaning 'fearing nothing', is a nod to the idea that this dinosaur was so gigantic that healthy adult Dreadnoughtus were probably impervious to attack by predators, says Kenneth Lacovara, a vertebrate palaeontologist at Drexel University in Philadelphia, Pennsylvania, who led the study. The bones of two individuals from the newly described species were found in rocks originally laid down as sediments on a floodplain some time between 66 million years and 84 million years ago.
Roughly 45% of the post-cranial bones of the larger specimen were recovered, Lacovara says. And if researchers use mirror images of bones present on one side of the creature, for example, to stand in for bones missing from the other side, they can produce a fossil reconstruction that includes about 70% of bones in the species' neck, body and tail."