While it seems that most of the world record-holding living animals have been well and truly discovered, the prehistoric world continues to amaze us each year with new finds that break long-held records, or fill in major missing gaps in evolutionary sequences.
Last year saw the announcement of the largest known dinosaur for which a body mass can be accurately calculated. Dreadnoughtus schrani was a sauropod dinosaur that lived around 77 million years ago in Argentina, and reached about 26 metres long and possibly weighed up to 59.3 tonnes (Scientific Reports 4/9/14).
Although single bones of very large dinosaurs that were possibly larger than Dreadnoughtus are known to exist, without enough of a skeleton preserved it’s impossible to determine if the living animals were really as big. It might have a long neck and short tail, or very long front limbs, as in Brachiosaurus, so calculation of its overall body mass really does depend on knowing an animals’s overall skeletal shape.
At the other end of the spectrum we saw one of the smallest known herbivorous horned dinosaurs announced, Aquilops americanus, from Montana, USA, that was about the size of a cat at around 1.6 kg and 70 cm long (PLOS1 10/12/14).
Yet for us palaeontologists, the big finds are always the ones in which a transitional fossil discovery suddenly clarifies the stages in the...
