Coelodonta thibetana
- Zandabecken, western Tibetan Plateau
Coelodonta thibetana is an extinct species of woolly rhinos ( Coelodonta ). It lived about 3.7 million years ago in the middle Pliocene, the Tibetan Plateau and is the earliest known representative of its genus that populated in the Pleistocene of Eurasia.
Features
The only skull found to date of Coelodonta thibetana was 77 cm long, due to the size of the skull a live weight of 1.8 t is reconstructed. He had a long been coated occipital bone, the nasal bone was strong and broadly rounded forward, with the distance to the premaxillary bone was 7.4 cm. This value is higher than that of C. nihowanensis, the phylegenetisch next newer type, while the classic woolly rhinoceros (C. antiquitatis ) both bone directly abut each other. The horn approaches to the skull speak for a relatively large nasal horn and a smaller frontal horn. In relation to body size and the types had probably the biggest horn of all rhino species, but it was obviously laterally flattened. Like the woolly head position was very steep due to the extended occiput. However, the characteristic of the genus of woolly rhinos bony nasal septum was not as well developed as in later types and pointed only in the front third of ossification on. The dental formula of C. thibetana is I 0/ 0 - C 0 /0 - P 3/3 - M 3/3 and thus corresponds to that of any other woolly rhinos, plus the ralativen Hochkronigkeit the teeth. However, the associated lower jaw to the skull still had the alveoli of the second milk incisor. This feature is also present in C. nihowanensis, but absent in the younger representatives of the woolly rhinos.
Paleobiology
With the help of isotope studies on the enamel of the teeth of C. thibetana conclusions about the diet of these Nashornart could be drawn. The tests were performed at different carbon isotopes indicate their relationship to each other statements about the prevailing climatic conditions. The values determined us to match those that have been measured at present-day Tibetan wild asses in parallel analyzes and talk consisting of grasses and shrubs for a preferred food component. Similar studies of oxygen isotopes showed again that the environment at that time was damp and cool and only after the middle Pliocene began a much drier climate.
System
Ronzotherium
Dicerotini
Dihoplus megarhinus
, Dihoplus ' kirchbergensis
Dihoplus ringstroemi
Dihoplus pikermiensis
Stephanorhinus etruscus
Dog Heimer rhinoceros ( Stephanorhinus hundsheimensis )
Steppe rhinoceros (p. hemitoechus )
C. thibetana
C. nihowanensis
C. tologojensis
Woolly rhinoceros (C. antiquatis )
Coelodonta thibetana is an early and original representatives of woolly rhinos. It evolved from a common ancestor with the steppe rhinoceros ( Stephanorhinus hemitoechus ), as this populated the Tibetan plateau. There, finally, an adaptation to the cold climate of high mountains took place, show similarly as about today yak (Bos mutus ). As the global climate cooled at the beginning of the Pleistocene and large parts of Eurasia icy, C. thibetana was able to extend its range and slowly advance to the north. The local population has evolved over time to the woolly rhinoceros (C. antiquatis ) further, which then penetrated to the west.
The first description of the species by Tao Deng et al. dates from 2011 and is based on a skull that was found in the western Tibetan Plateau Zandabecken ( IVPP V15908 ). The holotype nor unit focuses on the skull to the lower jaw and the first three cervical vertebrae. The specific epithet refers to the locality in Tibet.