Steppe mammoth

The steppe mammoth ("Mammuthus trogontherii", sometimes "Mammuthus armeniacus") is an extinct species of Elephantidae that ranged over most of northern Eurasia during the late Early and Middle Pleistocene, approximately 1.8 million-200,000 years ago. It evolved in Siberia during the Early Pleistocene from "Mammuthus meridionalis". It was the first stage in the evolution of the steppe and tundra elephants and the ancestor of the woolly mammoth and Columbian mammoth of the later Pleistocene. Populations of steppe mammoth may have persisted in northern China and Mongolia as recently as 33,000 years ago.
Taxonomy.
There is confusion about the correct scientific name for the steppe mammoth, either "Mammuthus armeniacus" (Falconer 1857) or "Mammuthus trogontherii" (Pohlig 1885). Falconer used material from Asian sources while Pohlig worked with fossil remains from Europe and both names appear in scientific publications, adding to the confusion. A first taxonomical overhaul was done by Maglio (1973) who decided that both names were synonyms, "armeniacus" being the older, hence the preferred name. However, in Shoshani & Tassy (1996) it was decided that the description of Pohlig prevailed, and consequently the correct name for the steppe mammoth is "M. trogontherii". It is unclear whether both forms are indeed identical and authors tend to use the name "M. trogontherii" for European material and "M. armeniacus" for Asian remains.
Several Japanese mammoth varieties from the early Pleistocene have been named, but all are now thought to be synonyms of "M. trogontherii".
Genetics.
DNA has been sequenced from two Siberian mammoth molars (which judging by morphology belong to the steppe mammoth); at over a million years old, this is the oldest ancient DNA ever recovered. The two genomes recovered belong to separate and distinct lineages: one is ancestral to the woolly mammoth, the other is a previously-unknown lineage. The latter lineage hybridized with woolly mammoths at least 420,000 years ago, giving rise to the Columbian mammoth.
Description.
The steppe mammoth had a short skull compared with "M. meridionalis" as well as a smaller jaw. The males had spiral tusks with a recurved tip that could grow as long as in old bulls; females on the other hand had thinner and slightly curved tusks.
With several individuals reaching tall at the shoulders, it is smaller than the largest proboscideans ever to have lived ("Palaeoloxodon namadicus" reached 22 tonnes and shoulder heights of ), but was larger than other mammoths. A skeleton mounted on the Azov Museum reaches at the shoulder, though this figure might be overestimated because the vertebrae have been placed between the tips of the shoulder blades. Another individual represented by a single humerus long found in Mosbach Sande, Germany, is estimated to have an in-the-flesh shoulder height of , weighed between and might be the largest mammoth found yet. Another estimate gives a shoulder height of and a weight of for the species.
Discovery.
Fossilized teeth are recovered, but skeletal parts are rare. The most complete skeleton of a steppe mammoth yet found was discovered in 1996 in Kikinda, Serbia. It was mounted, and put on display in 2005. The specimen is a female, which was about high, in length and with long tusks.
Another quite complete steppe mammoth was excavated in the cliffs of West Runton in Norfolk, UK; it preserves its jaws and teeth but is missing the upper part of its skull. A rare skull found in Auvergne, France, in 2008 will be examined by Dick Mol and Frédéric Lacombat in the Musée Crozatier in Le Puy-en-Velay.
In 1959 Zhou, M. Z described what he called a new species of mammoth, "M. sungari", that gained recent notoriety as the largest proboscidean due to a tall and long composite skeletal mount based on two individuals found in 1980. However, Wei "et al." (2010), who restudied the fossils referred to "M sungari", considered this species to be a junior synonym of "M. trogontherii". The authors state that some of the fossils are referrable to "M. trogontherii", while the others can be referred to "M. primigenius", according to morphological characters and measurements.
Evolution.
"M. trogontherii" is derived from "Mammuthus meridionalis", the oldest records of the species are known from China, at around 1.8-2 ma in age from the Nihewan Formation near Majuangou, Hebei. Steppe mammoths arrived in North America across Beringia around 1.5 million years ago, giving rise to the columbian mammoth (the ancestor was previously thought to be "M. meridionalis" but this was due to misinterpretation of tooth wear patterns). Steppe mammoths replaced "Mammuthus meridionalis" between 1-0.7 million years ago in Europe, in a complex diachronus mosaic pattern. European populations of "M. trogontherii" experienced a persistent size reduction towards the end of the Middle Pleistocene. A population of "M. trogontherii" in north east Siberia developed higher tooth plate count after 0.8 mya, reaching "M. primigenius" morphology by 400,000 years ago. "M. primigenius" replaced "M. trogontherii" in Europe around 200 kya. Relict populations of "M. trogontherii" may have persisted in Mongolia and North China well into the Last Glacial Period, with teeth of "M. trogontherii" like morphology in Shanxi being dated to 33.858–24.857 ka BP and Inner Mongolia to c. 33.7 ka BP.