Mini-mammoths' once roamed Greek island: Ancient elephants 'shrank' to three feet tall after becoming stranded on Crete. Three-foot tall mammoth example of 'insular dwarfism' Size of a baby mammoth, and smallest known.. Species could have existed as early as 3.5 million years ago. Other examples include Mediterranean donkeys. 'Reverse' of process by which birds such as dodos grow in size.
You knew about the shrinking Greek economy, but did you know about the shrinking wildlife?
Scientists have learned that a ‘mini-mammoth’ that stood just over three feet tall once roamed the island of Crete. Its larger ancestors are thought to have shrunk in size after becoming stranded on the Greek island - species often evolve to 'fit' their environment, thought to be caused by periodic food shortages Mammuthus creticus was roughly the size of a modern baby elephant and is the smallest mammoth known to have existed.
Dwarfism is an evolutionary trait often seen on islands where there may be insufficient space and resources to support full-sized species - it's thought that the process is driven by periodic food shortages Lead researcher Dr Victoria Herridge, from the Natural History Museum, said: ‘Dwarfism is a well-known evolutionary response of large mammals to island environments. Our findings show that on Crete, island dwarfism occurred to an extreme degree, producing the smallest mammoth known so far. M. creticus was identified by experts who re-examined a collection of fossil teeth at London's Natural History Museum.
The teeth were unearthed by pioneering fossil hunter Dorothea Bate in 1904. For more than a century they were assumed to belong to a dwarf-form of the straight-tusked elephant, Palaeoloxodon antiquus. But the new research, reported in the journal Proceedings of the Royal Society B, showed that the tooth enamel bore distinct mammoth hallmarks.
Further proof came when the scientists retraced Ms Bate's footsteps in Crete and found a mini-sized mammoth upper arm bone. M. creticus may be descended from one of two European mammoth species, M. meridionalis and M. rumanus, which became extinct around 800,000 years ago. M. rumanus evolved as long ago as 3.5 million years, which means the mini-mammoth could have ancient ancestry.
Herridge says, As such, we can show that this extreme insular evolution has taken place independently in two different non-dwarf elephant lineages of the straight-tusked elephants, Palaeoloxodon, and mammoths, Mammuthus. This opens up the possibility that dwarf mammoths evolved on Crete much earlier than we previously thought, perhaps as early as 3.5 million years ago. ‘Using the museum's collections alongside new measurements of an upper arm bone we found when we went back to Crete, we now know that Bate's specimens are mammoths with similarities to both M. meridionalis and M. rumanus. The arm bone in particular gives us the best evidence so far for how big or rather, how small this dwarf mammoth really was.’
Last month the body of the world's most well-preserved baby mammoth was been unveiled at an exhibition in Hong Kong ahead of a grand tour of Asia.
The 3ft beast, named Lyuba, was found in Siberian mountains by a reindeer herder five years ago and is thought to have drowned 40,000 years ago when she was just a month old.
Now her carcass will travel in sub-zero temperatures – in a bid to preserve her – to China, Indonesia, Singapore and Taiwan. The public has been allowed to glimpse at her body in a specially chilled room at the IFC Mall in Hong Kong. It is not yet known how long the tour will last – and is likely to depend on demand for viewings. Discovered in 2007, she is thought to have died in a mudslide at a month old. The mud effectively ‘pickled’ the baby, who has been named Lyuba, preserving her in a nearly pristine state.
Πηγή: http://www.dailymail.co.uk/sciencetech/article-2141566/Mini-mammoths-roamed-Greek-island-Their-ancestors-shrank-stranded-there.html
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου