THE largest marsupial and rodent ever to walk the earth have turned up in two fossil studies. The two extinct behemoths are raising questions about why no giants from each group exist today.
The marsupial (Diprotodon optatum) resembled a massive wombat and died out in Australia around 35,000 years ago. Few fossils exist, so researchers had been unable to estimate its size accurately. Now Stephen Wroe at the University of Sydney and his colleagues have developed a new method for putting a figure on the animal’s bulk. They calculated the relationship between limb bone measurements and total size in 18…
