Elasmotherium

of E. sibiricum|261x261px Elasmotherium was first described in 1808-1809 by German/Russian palaeontologist Gotthelf Fischer von Waldheim based on a left lower jaw, four molars, and the tooth root of the third premolar, which was gifted to Moscow University by princess Ekaterina Dashkova in 1807. He first announced the genus name at an 1808 presentation before the Moscow Society of Naturalists, and named the type species E. sibiricum a year later in 1809. The genus name derives from Ancient Greek ἔλασμα (élasma), meaning "metal plate", with the intended meaning "lamina", in reference to the laminated folding of the tooth enamel; and θηρίον (theríon), meaning "beast" and the species name sibericum is probably a reference to the predominantly Siberian origin of Princess Dashkova's collection. However, the specimen's exact origins are unknown. The specimen narrowly escaped destruction by being evacuated to Nizhny Novgorod during the French invasion of Russia in 1812, when most of the rest of Dashkova's collection was destroyed. The specimen was transferred to the Palaeontological Institute of the Academy of Sciences of the USSR (now the Russian Academy of Sciences) in Moscow during the mid-20th century.24-25 In 1916, a new genus, Enigmatherium and species E. stavropolitanum were named by Pavlova based on a single tooth found in the Northern Caucasus. This species was later recognised as a synonym of E. fischeri, named by Desmarest in 1820, which itself is now considered a synonym of the type species E. sibiricum. while younger estimates place the split during the Oligocene, around 35-23 million years ago. Unambiguous members of Elasmotheriinae first appeared during the Early Miocene, and the subfamily was speciose and widespread across Europe, Africa and Asia during the Miocene epoch. Cladogram of Rhinocerotidae after Borrani et al. 2025 (note: only a limited selection of elasmothere genera were included in the tree). }}}}}} }}}} }}}}}}}}}}}}}}}}}}}}}}}}}}Cladogram of Elasmotheriina (the subgroup including core members of Elasmotheriinae) after Sun et al. 2023:}} }}}}}}}}}}}}}}}}}}}}}}}}}}}} Elasmotherium is the only known member of Elasmotheriinae to haved survived after the Early Pliocene. with elasmotheriines declining as part of a broader decline of rhinocerotids and many other species of mammals during the late Miocene period. After originating and initially evolving in China (likely from Sinotherium) during the latest Miocene and Pliocene, Elasmotherium migrated westwards into Central Asia and Eastern Europe around 2.6 million years ago, during the earliest part of the Pleistocene epoch. Elasmotherium species are largely distinguished by differences in their tooth anatomy. and then on the basis of the dentition was redefined as a new species, E. chaprovicum (Shvyreva, 2004), named after the Khaprov Faunal Complex. The Khaprov is in the Middle Villafranchian, MN17, which spans the Piacenzian of the Late Pliocene and the Gelasian of the Early Pleistocene of Northern Caucasus, Moldova and Asia and has been dated to 2.6–2.2 Ma. This species is characterised by the relative thickness and roughness of its irregularly folded tooth enamel, its massive metapodial bones, and the morphology of the talus bone of the foot, which are relatively low, have a narrow trochlea and a wide part closest to the (distal) tip of the foot. The species is also known from numerous remains from the classical range of Elasmotherium, and some sources have considered this species to be a synonym of E. caucasicum, but it is currently considered distinct. This species is distinguished from other Elasmotherium species by several aspects of its dental anatomy, with the teeth being characterised by early closure of the roots, though the roots remain distinct from the crown of the tooth, and several morphological characters of the teeth, including the persistent presence of a postfossette (a depression of the tooth surface), as well as the shape of the protoloph and metaloph (which are raised areas of teeth). E. sibiricum, described by Johann Fischer von Waldheim in 1808 and chronologically the latest species of the sequence appeared in the Middle Pleistocene, ranging northwards to southern-central Russia, westwards into Ukraine and Moldova in Eastern Europe, eastwards into eastern Kazakhstan and southwards to Uzbekistan in Central Asia, and into Azerbaijan in the Caucasus. This species is distinguished from earlier Elasmotherium by having smaller teeth, a reduced number of premolars, open rooted (evergrowing) molars, as well as very thin and highly complicated enamel folding in the cheek teeth. == Description ==

Elasmotherium is the largest known rhinocerotid, and one of the largest members of Rhinocerotoidea, excluding the largest paraceratheres like Paraceratherium.supplementary material The largest known specimens of E. sibiricum reach up to in length, with shoulder heights of over , These make Elasmotherium comparable in size to the woolly mammoth (Mammuthus primigenius) and larger than the contemporary woolly rhinoceros (Coelodonta antiquitatis). The cervical vertebrae of the neck were very robust,Elasmotherium is typically reconstructed covered in a considerable layer of fur, generally based on the woolliness exemplified in contemporary megafauna such as woolly mammoths and the woolly rhinoceros. However, it is sometimes depicted as bare-skinned like modern rhinoceroses. == Palaeobiology ==

The angle made by the intersection of the plane of the occipital bone with the skull base is around 105–115°, indicating that the head was habitually held low, Valentin Teryaev in 1948 argued that Elasmotherium was a semi-aquatic animal that lived within and in close proximity to water including riverbanks and ponds, feeding on aquatic and nearshore plants with an ecology and physical appearance similar to a hippopotamus. Part of Teryaev's argument was based on the supposed presence of a fourth functional digit in the forefeet of Elasmotherium, similar to tapirs which predominantly inhabit wet environments, but this idea was later shown to be incorrect. Some other authors, while not necessarily agreeing with Teryaev's idea of a semi-aquatic Elasmotherium, have suggested that it predominantly lived near water, such as along river valleys, and foraged on aquatic and semi-aquatic plants. Modern high crowned (hypsodont) hoofed mammals are generally grazers of open environments, with the wrinkled enamel of Elasmotherium teeth suggested to possibly be an adaptation to feeding on tough, fibrous grass. The high crowned teeth of Elasmotherium have either been suggested to be an adaptation for feeding on grass or to compensate from the wear caused by the intake of grit on the food it was eating. == Relationship with humans and extinction ==

Elasmotherium sibiricum was previously thought to have gone extinct during the late Middle Pleistocene, around 200,000 years ago as a background extinction, but radiocarbon dates obtained from specimens found in southern European Russia shows its persistence in the region until at least 39,000 and possibly as late as 35,000 years ago, indicating that Elasmotherium survived well into the Last Glacial Period. A claimed later radiocarbon date of around 29,000 years ago from Pavlodar, in northern Kazakhstan is not considered credible. These late dates place Elasmotherium's extinction within the timeframe of the late Quaternary extinction event, when most large terrestrial animals became extinct, generally thought to be the result of climate change, hunting by the globally expanding population of modern humans, or the combination of both. However, there is very little evidence of human interaction with Elasmotherium, and their remains have never been found in any confirmed archaeological context. The last records of Elasmotherium, which date to Marine Isotope Stage 3, correspond to a period of pronounced climatic and environmental change induced by the oscillation between relatively warm interstadial and cool stadial periods, with the last records dating to around the onset of Heinrich stadial 4/Greenland stadial 8, caused by a Heinrich event (a large group of icebergs simultaneously breaking off the North American Laurentide Ice Sheet and travelling into the North Atlantic), corresponding with pronounced cooling, the disruption of grass and herb dominated ecosystems and the spread of the mammoth steppe-tundra across northern Eurasia. The specialised ecology and restricted geographical distribution of Elasmotherium may have contributed to its extinction. in France, which has been controversially argued to depict Elasmotherium, but otherwise considered a depiction of the woolly rhinoceros A claimed Late Pleistocene presence in Western Europe, based on a cave painting in Rouffignac Cave in France, which depicts a rhinoceros with a large single horn, has been doubted, because of the complete lack of any Western European remains of Elasmotherium,46-47 and other authors have considered this to be a depiction of the woolly rhinoceros. Other claimed depictions of Elasmotherium have been reported from Shulgan-Tash Cave in the southern Russian Urals, though other authors have considered the claims to be unproven, due to the ambiguous nature of the ochre drawings, and these could again be depictions of the woolly rhinoceros. Since the 19th century, Elasmotherium has been claimed to be the origin of folkloric creatures, particularly the unicorn, though the evidence in support of this hypothesis is conjectural, and Elasmotherium does not appear to have inhabited the areas where the mythological unicorn is thought to have originated, and the depiction of the unicorn may have been influenced by living rhinoceroses rather than Elasmotherium. As a consequence, E. sibiricum has sometimes been nicknamed the "Siberian Unicorn". ==See also==