Scientists on Tuesday unveiled body-weight estimates for an astounding 426 different dinosaur species using a formula based on the thickness of their leg bones, crowning the truly immense long-necked Argentinosaurus as the biggest of them all.
That plant-eating dinosaur weighed an earth-shaking 90 tonnes when it lived about 90 million years ago in Argentina. It is the largest known land creature in the planet's history.
" Argentinosaurus, that's the champion," said Oxford University palaeontologist Dr Roger Benson, who led the study.
In their dinosaur "weigh-in", the scientists included birds, which arose roughly 150 million years ago within a group of feathered dinosaurs called maniraptorans. A sparrow-sized bird called Qiliania that lived about 120 million years ago in China earned the distinction of being the smallest dinosaur, weighing 15 grams.
Benson noted that Argentinosaurus was about six million times the weight of Qiliania, and that both still fit within the dinosaur family. "That seems amazing to me," added Benson, whose study was published in the scientific journal PLOS Biology.
The largest meat-eating dinosaur was Tyrannosaurus rex, which weighed seven tonnes and is also the largest known land predator of all time.
Dinosaurs first appeared about 228 million years ago during the Triassic period, achieved stunning dimensions during the ensuing Jurassic period and then disappeared at the end of the Cretaceous period about 65 million years ago. All but the birds, that is.