''Nanotitanops'' is an extinct genus of Brontothere from the middle

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

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

. 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 Orthopteroids are insects which historically would have been included in the order Orthoptera and now may be placed in the Polyneoptera. When Carl Linnaeus started applying binomial names to animals in the 10th edition of his '' Systema Natura ...

insects from the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

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

Titans In Greek mythology, the Titans ( grc, οἱ Τῑτᾶνες, ''hoi Tītânes'', , ''ho Tītân'') were the pre-Olympian gods. According to the ''Theogony'' of Hesiod, they were the twelve children of the primordial parents Uranus (Sky) and Ga ...

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 (; ; pinyin: Jiāngsū, alternatively romanized as Kiangsu or Chiangsu) is an eastern coastal province of the People's Republic of China. It is one of the leading provinces in finance, education, technology, and tourism, with its ca ...

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

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

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

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