Mammuthus trogontherii, sometimes called the steppe mammoth, is an extinct species of mammoth that ranged over most of northern Eurasia during the Early and Middle Pleistocene, approximately 1.7 million-200,000 years ago. One of the largest mammoth species, it evolved in East Asia during the Early Pleistocene, around 1.8 million years ago, before migrating into North America around 1.5 million years ago, and into Europe during the Early/Middle Pleistocene transition, around 1 to 0.7 million years ago. It was the ancestor of the woolly mammoth and Columbian mammoth of the later Pleistocene.
Taxonomy
There was historically 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.[2] 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.[3] The status of Mammuthus armeniacus as a synonym of Mammuthus trogontherii has been supported by most recent authors.[4] The type specimens of the species are molars from the Süssenborn locality in Germany, dating to the early Middle Pleistocene, (MIS 16, approximately 676-621,000 years ago).[5]
Several Japanese mammoth varieties from the early Pleistocene have been named, but all are now thought to be synonyms of M. trogontherii.[6]
Description
Skeletal diagram of the 3.89 metre tall Zhalainuoer III specimen, including side on view (centre), top-down (above) and from the front minus the head (left)Size comparison of the fragmentary "Mosbach mammoth" estimated to be 4.5 metres tall.
Mammuthus trogontherii was one of the largest mammoth species, with males on average being about 4 m (13.1 ft) tall at the shoulders and about 11 tonnes (10.8 long tons; 12.1 short tons) in weight and females on average being about 3.7 m (12.1 ft) tall at the shoulders and about 9.5 tonnes (9.3 long tons; 10.5 short tons) in weight, considerably exceeding the size of modern elephants.[7][8] A skeleton mounted on the Azov Museum reaches 4.5 m (14.8 ft) at the shoulder, though this figure might be overestimated because the vertebrae have been placed between the tips of the shoulder blades.[9] A largely complete specimen (Zhalainuoer III) from Inner Mongolia, China, was estimated to have had a shoulder height of around 3.69 m (12.1 ft) measured at the top of the scapula, which represents a flesh shoulder height of 3.89 m (12.8 ft), with a body mass estimated via volumetric analysis at 10.4 tonnes (10.2 long tons; 11.5 short tons).[10][7] Another individual represented by a single giant humerus 1.46 m (4.8 ft) long and an associated pelvis found in Mosbach Sande, Germany, is estimated to have had a shoulder height of 4.5 metres (14.8 ft) and a weight of 14.3 tonnes (14.1 long tons; 15.8 short tons) via regression analysis.[7]
Jaw with molar teeth
The skull was high-domed and short, and bore twisted tusks. The lower jaw was short and deep.[10] The number of lamellae on the third molars is around 18–22, noticeably lower than the number typically present in M. primigenius (though some European specimens of M. primigenius have counts which overlap with those of M. trogontherii).[5] The body has around 19 thoracic vertebrae and 5 or 6 sacral vertebrae, with the first few thoracic vertebrae having long neural spines.[10] The tusks were proportionally large, among the largest known among proboscideans, with one large tusk from the Kostolac Basin in Serbia measuring 4.2 metres (14 ft) in length, with an estimated mass of 213 kilograms (470 lb).[11]
Sequenced genomes suggests that Early Pleistocene M. trogontherii specimens from Siberia, around 1 million years old, had already developed many of the genetic changes thought to be responsible for traits that were adaptations for living in cold environments characteristic of woolly mammoths.[12] Due to the cold climates it inhabited and short tail, Mammuthus trogontherii is suggested to have borne a coat of fur, which was probably somewhat thinner than that of the woolly mammoth.[10]
Ecology
Steppe mammoths are thought to have been grazers to grazing-predominant mixed feeders, distinct from Mammuthus meridionalis, whose diet was highly variable but on average included more browse.[13] It was often associated with cold steppe environments, as its common name would suggest, but was not confined to them, as evidenced by the early Middle Pleistocene West Runton Mammoth specimen from Norfolk, England, which was associated with a temperate forested environment.[14]
Evolution
M. trogontherii is suggested to have derived from Mammuthus meridionalis. The oldest records M. trogontherii are known from China, around 1.7 million years old, from the Nihewan Formation near Majuangou, Hebei. Steppe mammoths arrived in North America across Beringia around 1.5-1.3 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).[15][12] Steppe mammoths replaced Mammuthus meridionalis between 1–0.7 million years ago in Europe, in a complex diachronous mosaic pattern, coincident with the arrival of the straight-tusked elephant (Palaeoloxodon antiquus) to Europe.[16] European populations of M. trogontherii experienced a persistent size reduction towards the end of the Middle Pleistocene, from around 400,000 years ago onwards.[16][12] Mammoths with M. primigenius (woolly mammoth)-type molar morphology had emerged in Northeast Siberia from M. trogontherii by around 600-500,000 years ago, reaching the typical morphology of M. primigenius around 400,000 years ago. Mammoths with M. primigenius type molar morphology displaced those of M. trogontherii type in Europe over the course of the late Middle Pleistocene, which was largely complete by 200,000 years ago (~MIS 7/6 boundary) in a protracted highly complex pattern including some molars with intermediate morphology between the two species that likely reflects gene flow from Siberian woolly mammoths into European M. trogontherii.[5] The replacement of European M. trogontherii by woolly mammoths is widely considered to mark the extinction of the species.[12]
Relationship with humans
At the Bełchatów coal mine in Poland, dating to the late Middle Pleistocene (in the interglacial period of either MIS 11 or MIS 9, around 425-300,000 years ago), remains of M. trogontherii have been found with cut marks, suggested to represent evidence of butchery by archaic humans.[17] Sites with evidence of both humans and M. trogontherii in Europe are rare, especially compared to the contemporaneous straight-tusked elephant, which is suggested to be the result of them primarily occupying different habitats.[18]
^Maglio, V. J. (1973). "Origin and Evolution of the Elephantidae". Trans Am Philos Soc. 63 (3): 1–149. doi:10.2307/1006229. JSTOR1006229.
^Shoshani, J.; Tassy, P., eds. (1996). The Proboscidea : Evolution and Palaeoecology of Elephants and Their Relatives. Oxford: Oxford University Press. ISBN0-19-854652-1.
Benes, Josef (1979). Prehistoric Animals and Plants. London: Hamlyn. p. 271. ISBN0-600-30341-1.
Augusti, Jordi; Anton, Mauricio (2002). Mammoths, Sabertooths and Hominids 65 Million Years of Mammalian Evolution in Europe. Columbia University Press. ISBN0-231-11640-3.
Lister, Adrian; Bahn, Paul (1997). Mammuts : Riesen der Eiszeit (in German). Sigmaringen: Thorbecke Verlag. ISBN3-7995-9050-1.
Mol, Dick; Lacombat, Frédéric (2010). Mammoths & Mastodons of Haute-Loire. Drukware. p. 271. ISBN978-2-911794-97-1. (English and French)
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