''Nanotitanops'' is an extinct genus of

Brontothere Brontotheriidae is a family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like rhinos with some developing bony nose horns, and were some of ...

from the middle

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. It contains a single species, ''N. shanghuangensis''. It is known only from isolated teeth, the smallest of any known Brontothere.

Description

This genus is currently known only from dental evidence. Described specimens do not exceed 13.55 millimeters in length and 12 millimeters in width. While it retains some basal traits, the teeth possess features which point toward it being relatively derived. It differs from basal designs in having relatively longer and narrower molars with stronger development of buccal shearing crests and only a vestigial paraconule on the upper molars. The dental morphology is most similar to the much larger genera '' Epimanteoceras'' and '' Rhinotitan''.Li, S. (2018). A new species of Brontotheriidae from the Middle Eocene of Junggar Basin, Xinjiang, China. ''Vertebrata PalAsiatica'', ''56''(1), 25-44.

Relationships

The exact placement of ''Nanotitanops'' within Brontotheridae is uncertain. There are other small brontotheres from the Eocene of Asia such as '' Microtitan'', '' Pygmaetitan'', and '' Protitan'' though morphological evidence does not support a monophyletic relationship between them. Morphological analysis tends to put ''Nanotitanops'' in a polytomy near the node of the subfamily Brontotheriinae. It has been proposed as a possible sister taxon to ''Epimanteoceras formosa.'' ''Nanotitanops'' was originally named '' Nanotitan'', but this genus name was preoccupied by an orthopteroid insects from the

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

Kyrgyzstan Kyrgyzstan, officially the Kyrgyz Republic, is a landlocked country in Central Asia lying in the Tian Shan and Pamir Mountains, Pamir mountain ranges. Bishkek is the Capital city, capital and List of cities in Kyrgyzstan, largest city. Kyrgyz ...

. The genus name is derived from the Greek ''nanos,'' meaning dwarf, ''titan,'' referring to the

Titans In Greek mythology, the Titans ( ; ) were the pre-Twelve Olympians, Olympian gods. According to the ''Theogony'' of Hesiod, they were the twelve children of the primordial parents Uranus (mythology), Uranus (Sky) and Gaia (Earth). The six male ...

of Greek mythology, and the Greek suffix -''ops,'' meaning face. The specific epithet of the only species refers to the village in which the first and only specimens have been found.

Paleobiology

This genus is only described from the astoundingly rich middle Eocene fissure-filling near the village of Shanghuang in southern

Jiangsu Province Jiangsu is a coastal province in East China. It is one of the leading provinces in finance, education, technology, and tourism, with its capital in Nanjing. Jiangsu is the third smallest, but the fifth most populous, with a population of 84. ...

, China. The fissures also held another small brontothere, ''Microtitan cf. mongoliensis'', a species known from the

Irdin Manha Formation The Irdin Manha Formation is a geology, geological formation from the Eocene located in Inner Mongolia, China, a few kilometres south of the Mongolian border.. Retrieved July 2013. Fossil content Mammals U.S. paleontologists Henry Fairfield O ...

of the Nei Mongol Autonomous Region of China. They are both known only from a site dubbed Fissure D. This fissure contained various other mammalian fauna including the primitive cricetid rodent ''Pappocricetodon antiquus'' and the

omomyid Omomyidae is a group of early primates that radiated during the Eocene epoch between about (mya). Fossil omomyids are found in North America, Europe & Asia, making it one of two groups of Eocene primates with a geographic distribution spanning ...

or omomyid-like primate '' Macrotarsius macrorhysis.'' The nearby fissures have included a large diversity of

primate Primates is an order (biology), order of mammals, which is further divided into the Strepsirrhini, strepsirrhines, which include lemurs, galagos, and Lorisidae, lorisids; and the Haplorhini, haplorhines, which include Tarsiiformes, tarsiers a ...

s. There is also a Dichobunid known from the area, called '' Elaschitotherium qii.''GRÉGOIRE, M., GUO, J., & BEARD, K. C. (2004). A new small dichobunid artiodactyl from Shanghuang (middle Eocene, eastern China): implications for the early evolution of proto-selenodonts in Asia. ''Bulletin of Carnegie Museum of Natural History'', ''2004''(36), 177-197.

References

{{Taxonbar, from=Q15836280 Eocene animals of Asia Brontotheres Brontotheres of Asia Clarno Formation