The world's smallest mammoth lived in Crete
9 May 2012, by Tamera Jones
The Greek island of Crete was once home to the tiniest species of mammoth ever to have existed: Mammuthus creticus, say scientists.
At just over a metre tall and weighing around 300 kilograms, this extremely small mammoth was about the same size as a baby Asian elephant and the now-extinct Sicilian dwarf elephant Palaeoloxodon falconeri.
'It might have been a bit chunkier than a baby Asian elephant. And it probably would've had a different shaped head and curved tusks as an adult. But it probably didn't have a woolly coat like the later woolly mammoth,' says Dr Victoria Herridge from London's Natural History Museum, who led the study, published in Proceedings of the Royal Society B.
The findings resolve a long-standing debate over the identity of the fossilised remains of six teeth collected by British palaeontologist Dorothy Bate from Cape Malekas, Crete in 1904.
Most researchers, including Bate, assumed they'd come from a tiny descendent of the straight-tusked elephant, Palaeoloxodon antiquus. But it now seems the teeth instead belonged to a very small mammoth.
The site at Cape Malekas, Crete, where the fossil teeth were found.
'Everything about these teeth say mammoth,' says Herridge.
Small elephants were common on many islands around the world between 2,600,000 and just 4000 years ago - a period which scientists call the Pleistocene. And, for some as-yet-unknown reason, the Mediterranean was home to the tiniest.
With the exception of a 1.51-metre-tall mammoth from Sardinia, until now, most researchers thought that all the Mediterranean's dwarf trunked mammals descended from a common ancestor, the straight-tusked elephant.
A 2006 study on ancient DNA from a rib from Cape Malekas challenged this idea. It concluded that the bone's owner was probably a mammoth. Unfortunately, that study has since been discredited.
To settle the argument once and for all, Herridge and colleague Professor Adrian Lister, also from the Natural History Museum, decided to analyse the teeth collected by Bate – now held at the museum, along with teeth and a leg bone they'd found at the same site in Crete.
'We wanted to know if all of these dwarf elephants descended from a common ancestor, the straight-tusked elephant, or did some originate from the mammoth?' says Herridge.
They found that the pattern of wear on the teeth show almost conclusively that they belonged to a mammoth.
'Now we've got independent evidence that supports the idea that the teeth's owner was a tiny mammoth,' Herridge says.
She and Lister think the dwarf mammoth probably descended from one of the first European mammoth species, either Mammuthus rumanus or Mammuthus meridionalis. This suggests that dwarf mammoths may have evolved much earlier than previously thought - anywhere from one to three million years ago.
'We think we now have enough information to rename this creature Mammuthus creticus rather than Pelaeoloxodon creticus to show that it had mammoth origins.'
Dr Herridge with mammoth teeth.
Because this dwarf mammoth lived in southern Europe and probably descended from one of the early European mammoths that weren't adapted to a cold ice-age environment, the researchers suspect it wouldn't have had a woolly coat.
Scientists have long known that large mammals tend to shrink over thousands of years after becoming isolated on an island. They call this the 'island rule'.
'The opposite is true for small mammals; they tend to get bigger over time,' says Herridge.
There are three main explanations for this: limited resources; lack of predators; and very little, or no competition. Right now, scientists think having no predators and therefore no need to be big to deter them may be a particularly important cause of dwarfism.
The study demonstrates that small size almost certainly evolved independently in both elephants and mammoths.
Victoria L. Herridge and Adrian M. Lister, Extreme insular dwarfism evolved in a mammoth, Proc. R. Soc. B, published 9 May 2012, doi:10.1098/rspb.2012.0671
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