An elephant shakes a tree

Mammoths get all the attention. Like an annoying younger sibling, they hog a limelight that should be more equally shared. Occasionally, the mastodon gets a whisp of publicity, which is notable mostly for its rarity. The vast family of proboscideans barely get a look in. When did you last hear any news about exciting new finds of Stegodon or Cuvieronius or Sinomastodon or Notiomastodon or Stegomastodon? What about Palaeoloxodon?

I thought so.

Skeleton of Palaeoloxodon antiquus in the Museo paleontologico of the university Sapienzia, Rome. Public Domain Image via Wikimedia Commons.

Reconstruction of Palaeoloxodon antiquus and calf. Image by Apotea via Wikimedia Commons.

Palaeoloxodon antiquus should be better known. This species, also called the straight-tusked elephant, was found all over Eurasia during the warm periods of the Pleistocene. Even in Britain. We’ve got bones of this giant from interglacial gravels underneath Trafalgar square, on the east Anglian coast, and from right under the route now taken by the Channel Tunnel rail link. In Europe, Palaeoloxodon even submarined its way to some of the Mediterranean islands and evolved into unique, teeny-tiny forms on the islands of Malta, Cyprus, Tilos, and Sicily (mammoths did something similar on the island of Crete). In fact, if you close your eyes and squint real hard, there is some controversial evidence that these dwarf elephants may have squeaked into the historical period. A very interesting panel from the tomb of Rekh-Mi-Re, an 18th dynasty vizier, buried in Thebes, shows what appears to be a fully mature elephant with tusks, but only waist high. Could it have come from a Mediterranean population? Possibly, but it could also just be a stylistic convention. We don’t have a good idea of when the insular elephants went extinct but it was most likely sometime during the middle Holocene, with some perhaps hanging on until the Bronze age.

Size comparison of the dwarfed Tilos elephant compared to mainland Palaeoloxodon antiquus. Image by A. Mangione from Masseti 2001

Elephant painting from the tomb of Rekh-Mi-Re. It has also been used to suggest a trading route between ancient Egypt and Wrangel Island(!). Image from Masseti 2001

We do have a better idea of when the fullsized straight-tusker disappeared. It seems to have been widespread during the height of the last interglacial when temperatures were comparatively balmy. It shared the European landscape with hippos (Hippopotamus amphibius), Merck’s rhino (Stephanorhinus kirchbergensis) and other typically warm-adapted fauna. It probably wasn’t as hirsute as its woolly cousin and it’s helpful to picture the living animal as an Asian elephant on steroids. Four metres to the shoulders, longer tusks, just mammoth, mastodonic, huge overall. When the climate started to cool again, it probably retreated to some of the classic Pleistocene refugia: Iberia, Italy, perhaps the Balkans too. Some evocative footprints attributed to P. antiquus have been excavated in Portugal from fossilised sand dunes. However, even these regions weren’t warm enough and the mainland straight-tusked elephant was probably gone by the end of the Middle Pleistocene. Although, having said that, there are radiocarbon dates for late Pleistocene Palaeloxodon in Portugal, but these haven’t convinced everyone. Even more fringe is the idea that straight-tusked elephants were roaming China during the historical period. This is based on analysis of bronze artefacts which show elephants with unusual trunk features. But again this could just by stylistic convention.

An early Chinese bronze depiction of an elephant. It’s claimed that the trunk tip contains two fingers- a feature found in African elephants and mammoths but not Asian elephants. Image from Li et al. 2011

Right from the start, researchers have been pretty clear about where the affinities of P. antquus lay. It started off as Elephas antiquus; Elephas is the genus of the Indian elephant (Elephas maximus). However, as is its wont, ancient DNA has now come along and mixed things up a little. This week Meyer et al. published Palaeoloxodon antiquus mitochondrial genomes and nuclear DNA from Germany and it has turned things on their head. Despite reams of morphological data suggesting the straight-tusker and the Asian elephant were sister species, the DNA data puts Palaeoloxodon squarely with the African elephants. Not only that but it puts it as sister to the African forest elephant, Loxodonta cyclotis. This means that there is more genetic distance between the African savannah elephant (L. africana) and the African forest elephant that are found today, than there is between the forest elephant and Palaeoloxodon antiquus.

Above: Comparison of the phylogenies produced from mitochondrial DNA and nuclear DNA, showing their high support and congruence. Below: Reconstructed elephant family tree, based on the new data. Images from Meyer et al.

This is important. If you’ve paid any attention to the news recently then you know that elephants are in serious trouble. As in, we are killing them all. Poachers and ivory traders don’t give a shit about the difference between savannah and forest elephants, but we should. The destruction of wild elephants may be pushing forest elephants to the brink of extinction yet we can still look at the savannah elephants and think we have time to save them. We don’t. The continued loss of forest elephants represents the loss of a distinct lineage that needs to be recognised as a different species. Hopefully the reshuffling of Palaeoloxodon will help to show that the two African elephants are distinct, unique species and conservation measures can be tailored to their distinct, unique needs.

Elephant killed by poachers. Image by Ina96 via Wikimedia Commons.

 

Written by Ross Barnett (@DeepFriedDNA)

Further Reading:

Binladen, J., M. T. Gilbert, and E. Willerslev. “800,000 Year Old Mammoth DNA, Modern Elephant DNA or PCR Artefact?”. Biol Lett 3, no. 1 (Feb 22 2007): 55-6; discussion 60-3.[Abstract]

de Carvalho, C. N., S. Figueirido, and J. Belo. “Vertebrate Tracks and Trackways from the Pleistocene Eolianites of Sw Portugal.” Comunicações Geológicas, no. 103 (2016): 101-16.[Full Text]

Franks, J. W. “Interglacial Deposits at Trafalgar Square, London.” The New Phytologist 59 (1960): 145-50.[Abstract]

Herridge, V. L., and A. M. Lister. “Extreme Insular Dwarfism Evolved in a Mammoth.” Proc Biol Sci 279, no. 1741 (Aug 22 2012): 3193-200.[FullText]

Li, J., Y. Hou, Y. Li, and J Zhang. “The Latest Straight-Tusked Elephants (Palaeoloxodon)? “Wild Elephants” Lived 3,000 Years Ago in North China.” Quaternary International 281 (2011): 84-88.[Abstract]

Masseti, M. “Did Endemic Dwarf Elephants Survive on Mediterranean Islands up to Protohistorical Times?” In The World of Elephants – International Congress, 402-06. Rome, 2001.[FullText]

Meyer, M., E. Palkopoulou, S. Baleka, M. Stiller, K. E. H. Penkman, K. W. Alt, Y. Ishida, et al. “Palaeogenomes of Eurasian Straight- Tusked Elephants Challenge the Current View of Elephant Evolution.” eLife, no. 25413 (2017): 1-14.[Full Text]

Orlando, L., M. Pages, S. Calvignac, S. Hughes, and C. Hanni. “Does the 43 Bp Sequence from an 800,000 Year Old Cretan Dwarf Elephantid Really Rewrite the Textbook on Mammoths?”. Biol Lett 3, no. 1 (Feb 22 2007): 57-9; discussion 60-3.[FullText]

Palombo, M. R. “Endemic Elephants of the Mediterranean Islands: Knowledge, Problems and Perspectives.” In The World of Elephants – International Congress. Rome, 2001.[FullText]

Poulakakis, N., A.P. Parmakelis, P. Lymberakis, M. Mylonas, E. Zouras, D. S. Reese, S. Glaberman, and A. Caccone. “Ancient DNA Forces Reconsideration of Evolutionary History of Mediterranean Pygmy Elephantids.” Biology Letters (2006).[Abstract]

Stuart, A. J. “The Extinction of Woolly Mammoth (Mammuthus Primigenius) and Striaght-Tusked Elephant (Palaeoloxodon Antiquus) in Europe.” Quaternary International 126-128 (2005): 171-77.[FullText]

 

 

 

 

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This entry was posted in Columbian Mammoth, Deinotherium, Extinction, Hippopotamus, Mastodon, Palaeoloxodon, Stegodon, Steppe Mammoth, Woolly Mammoth and tagged , , , , , , , , , , , . Bookmark the permalink.

4 Responses to An elephant shakes a tree

  1. LeeB. says:

    Another interesting point is that DNA from dwarf elephants from Cyprys and Tilos show a relationship with Elephas, suggesting that rather than being descended from Palaeoloxodon they may have descended from the large Elephas known from Anatolia.

    t looks like there is going to have to be a lot more study of all these forms.

    Also Elephas iolensis from the Sudan at a site called Natodomerai has been dated to about 35000 years ago; it would be very interesting to try to get DNA from this specimen too, and also from the Palaeoloxodon specimens known from China and Japan that are also from relatively recent dates.

    LeeB.

  2. Hi Lee, The Cyprus and Tilos fossil DNA was done by the group that was rebutted multiple times for their study of proboscidean DNA. So far no-one has convinced the field that they have genuine mediterranean elephant DNA. A relationship with Elephas is theoretically possible given the late survival of Elephas in the middle east but I don’t think its particularly supported by the morphology. DNA from Sudan would be very interesting but the likelihood of getting DNA of that age from an equatorial site would be very low.

  3. LeeB. says:

    I wonder how much variation there is in the collagen and other proteins between the different elephant and mammoth species.
    Because the proteins last much longer in the bones than DNA does.
    And collagen fingerprinting has started to produce all kind of interesting results; giving the relationships of Bibymalagasy to Tenrics; and Litopterns and Notoungulates to Artiodactyls and Perissodactyls for instance.

    Archaeologists have also used it to differentiate sheep and goat bones, so some degree of differentiation is possible even with related groups of species.

    LeeB.

  4. Pingback: A very brief introduction to mammoths | TwilightBeasts

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