Researchers from the Natural History Museum in UK have identified the world’s smallest species of mammoth known to date.
The Cretan dwarf mammoth may have looked like a dwarf version of this full-size mammoth (Tracy O)
The newly identified dwarf mammoth, Mammuthus creticus, lived on the Greek island Crete and was some 1 meter tall. It weighed about 300 kg, half the weight of the previous known smallest dwarf mammoth, M. lamarmorai.
Fossils of M. creticus were unearthed in 1904 in Cape Malekas, Crete, and have been now re-examined and identified by the Natural History Museum’s experts.
It was previously thought that the Cretan dwarf mammoth was most likely a descendant of the extinct straight-tusked elephant, Palaeoloxodon antiquus, because this was the ancestor of nearly all the other extinct dwarf elephants found on various Mediterranean islands including Sicily, Malta and Cyprus. But the new study, published in the Proceedings of the Royal Society B, shows that this was not the case.
“Our work has meant that we can not only show it is a mammoth, but also demonstrate it is the smallest mammoth known to have existed,” said Dr. Victoria Herridge, an expert at the Natural History Museum.
Mammoths had twisted tusks and a single-domed head. But it is an elephant’s teeth that are most often preserved as fossils and these are used to tell elephant species apart. The teeth wear down during the animal’s life, creating a surface with enamel ‘rings’.
“The enamel rings on the Cretan tooth fossil had 3 character features that resembled mammoths, the genus Mammuthus, and, importantly, not the straight-tusked elephant Palaeoloxodon,” said Dr. Herridge. “Once we had identified it as a mammoth, we then used tooth shape to help us work out which species of mammoth it was most like.”
They compared the Cretan specimen to species of elephant known to have lived in mainland Europe in the past, the 3 mammoth species, Mammuthus rumanus, M. meridionalis and M. trogontherii, as well as P. antiquus.
They also discovered new fossils of the Cretan dwarf mammoth from the original Cape Malekas site, located using the notes and diaries of pioneering fossil hunter Dorothea Bate who collected the original Cretan specimens in 1904. A fragment of an upper arm bone allowed the team to take a measurement of the total bone length so they could reconstruct the size of the adult mammoth as approximately 1.1m tall.
The findings show the Cretan specimen was most similar to the species M. meridionalis that lived in Europe 2.5 million to 800,000 years ago.
“But we couldn’t rule out another species M. rumanus,” said Dr. Herridge. “M. rumanus is the earliest species of mammoth found in Europe – as long ago as 3.5 million years. This means the ancestor of M. creticus could have reached Crete as long ago as 3.5 million years.”
Dwarfism is a well-known evolutionary response of large mammals living on islands, known as the Island Rule (which conversely includes small mammals becoming larger). However, the Cretan animal was not only a dwarf, it was an extreme dwarf.
“This is the first time that extreme island dwarfism has been shown to have occurred in mammoths,” Dr. Herridge concluded.
