''Tsaidamotherium'' is an extinct genus of Late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

ovibovinid caprine from the Tibetan Plateau of Northwestern China. Both known species are extremely unusual in that the horns are of unequal sizes: the left horn core is several times smaller than the right horn core. Although it is originally considered that it belongs to the tribe

Ovibovini The subfamily Caprinae, also sometimes referred to as the tribe Caprini, is part of the ruminant family Bovidae, and consists of mostly medium-sized bovids. A member of this subfamily is called a caprine, or, more informally, a goat-antelope (a ...

, close to the

muskox The muskox (''Ovibos moschatus'', in Latin "musky sheep-ox"), also spelled musk ox and musk-ox, plural muskoxen or musk oxen (in iu, ᐅᒥᖕᒪᒃ, umingmak; in Woods Cree: ), is a hoofed mammal of the family Bovidae. Native to the Arctic, ...

, ''Ovibos moschatus'', a study in 2022 posits ''Tsaidamotherium'' as a

giraffoidea Giraffoidea is a superfamily that includes the families Climacoceratidae, Antilocapridae, and Giraffidae. The only extant members in the superfamily are the pronghorn, giraffe, and okapi. The Climacoceratidae are also placed in the superfamil ...

n genus in the family Prolibytheriidae together with ''

Prolibytherium ''Prolibytherium'' is an extinct genus of prolibytheriid artiodactyl ungulate native to Middle Miocene North Africa and Pakistan, from around 16.9 to 15.97 million years ago. Fossils of ''Prolibytherium'' were found in the Marada Formation of ...

'' and ''

Discokeryx ''Discokeryx'' is an extinct genus of even-toed ungulates, possibly related to the modern giraffe and okapi. ''D. xiezhi'' was alive during the Early Miocene period 17–16.9 million years ago. Fossilized remains of this animal were discovered i ...

''.

Etymology

The generic name refers to the Qaidam Basin, the region where the holotype of the type species, ''T. hedini'' was found. The specific name "hedini" honors Dr Sven Hedin. The specific name "brevirostrum" refers to the short muzzle of ''T. brevirostrums holotype skull.

Species

So far, there are two known species, ''T. hedini'', and ''T. brevirostrum''. The scrappy remains of the first species, ''T. hedini'', were discovered by Dr Hedin at the Qaidam Basin during the Sino-Swedish Scientific Expedition to Northwest China during the 1930s. Partial remains of two individuals were discovered in the Liushu Formation within the Linxia Basin in

Hezheng County Hezheng County () is a county in the Linxia Hui Autonomous Prefecture, province of Gansu of the People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous ...

, Gansu, in 2004, and were described as ''T. brevirostrum'' in 2013.

Paleobiology

The skulls of both species had large nasal cavities, suggesting the living animals had broad, vaulted muzzles like those of the takin or

Saiga antelope The saiga antelope (, ''Saiga tatarica''), or saiga, is a critically endangered antelope which during antiquity inhabited a vast area of the Eurasian steppe spanning the foothills of the Carpathian Mountains in the northwest and Caucasus in t ...

. The right horn core of ''T. hedini'' is tall and conical, suggesting the right horn would have resembled a Phrygian cap. In ''T. brevirostrum'', the right horn corn is much shorter and flatter, suggesting the right horn would have appeared squashed or flattened in comparison.

Paleoecology

During the late Miocene, the remains of the fossil horse ''

Hipparion ''Hipparion'' (Greek, "pony") is an extinct genus of horse that lived in North America, Asia, Europe, and Africa during the Miocene through Pleistocene ~23 Mya—781,000 years ago. It lived in non-forested, grassy plains, shortgrass prairie or ...

'' suggests that the Linxia and Qaidam basins were hot and semi-arid savanna environments. However, the anatomy of ''Tsaidamotherium'' (the vaulted muzzle, in particular), though, suggests that the living animals lived in comparatively cold environments. It is probable that the living animals had adapted to living in mountainous areas that had formed during a phase of

tectonic uplift Tectonic uplift is the geologic uplift of Earth's surface that is attributed to plate tectonics. While isostatic response is important, an increase in the mean elevation of a region can only occur in response to tectonic processes of crustal th ...

in Northwestern China at the beginning of the Late Miocene.

References

Prehistoric caprids Miocene genus extinctions Miocene mammals of Asia Fossils of China Fossil taxa described in 1935 Prehistoric Artiodactyla genera {{paleo-eventoedungulate-stub