Paraceratherium

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Paraceratherium
Skeletal reconstruction of a Paraceratherium

Skeletal reconstruction of a Paraceratherium

Temporal occurrence
Oligocene to Lower Miocene
34 to 22 million years
Locations
Systematics
Mammals (mammalia)
Higher mammals (Eutheria)
Laurasiatheria
Unpaired ungulate (Perissodactyla)
Indricotheriidae
Paraceratherium
Scientific name
Paraceratherium
Forster Cooper , 1911

Paraceratherium (formerly also described as Baluchitherium , Indricotherium or Dzungariotherium ) is a genus from the extinct family of Indricotheriidae , which belongs to the rhinoceros-like (Rhinocerotoidea) and was the largest land-dwelling mammal of all time,weighing up to 20 tons. Only some of the largest proboscis animals could have reached similar dimensions. It was also characterized by long legs, an elongated neck and a comparatively small skull. The genus lived in the Oligocene and the Lower Miocene around 34 to around 22 million years ago. It is known from numerous, partly well-preserved fossil remains from East , Central and West Asia , but also occurred in today's Southeast Europe . According to studies of the molars of Paraceratherium , it lived mainly on soft vegetable food, while it lived in partly open landscapes that existed under a subtropical, warm climate. The frequently used synonym names are based on independent descriptions of find material from different find regions, which were mostly created at very short intervals at the beginning of the 20th century, but were finally officiallyunitedwith Paraceratherium in 1989. The scientific discovery of the genus began in the early 20th century. The name Paraceratherium is derived from the Greek words παρά ( pará ) for “next to”, κέρας ( keras ) for “horn” and θηρίον ( thēríon ) for “animal” and refers to the close relationship with the rhinos .

features

Habitus

More recent life reconstruction of Paraceratherium

Paraceratherium was a relatively long-legged and long-necked animal with a strong build and a relatively small head. On the basis of the bones found, a head-trunk length of 7.4 to 8.7 m and a shoulder height of 4.5 to 5 m are assumed for the largest species (without taking into account the covering of the skeleton by soft tissue ), the neck length was reconstructed probably around 2 to 2.5 m. The weight reached an estimated 15 to 20 tons, females were possibly significantly smaller. Smaller species were only around 6.2 m long and weighed around 7 to 9 tons.

Skull and dentition features

Skull of Paraceratherium
Maxillary teeth from Paraceratherium

A completely preserved skull was up to 130 cm long and at the zygomatic arches up to 61 cm wide, some fragmented pieces suggest even larger specimens. The skull was extremely elongated and narrow and low in the area of ​​the brain skull. However, the upper skull had a slight dome-like bulge in the middle. In relation to the whole body it is rather small compared to today's rhinos. The nasal bone showed only a weak development and had no roughening, which shows that the genus had no horns. The occiput was narrow and long and not built as wide as that of today's rhinos. It only had a weak occipital bulge, which suggests less well-developed neck muscles - another indication of the absence of a horn. However, the joints at the back of the head for the spine were enormous. The lower jaw was long and narrow, but built quite strong. The symphysis reached the third premolar and was therefore extremely long and robust.

Paraceratherium had a partially reduced dentition with the following dental formula . In the front dentition Paraceratherium had a pair of incisors above and below , which had a dagger-like shape and with a length of 6 to 7 cm resembled small tusks. The second incisors (I2) were formed at the top and sat more vertically or slightly angled forward in the jaw. In the lower jaw, however, the first incisors (I1) were in a horizontal or inclined position. Another small, outer pair of incisors could sometimes be formed in the lower jaw, and a rudimentary canine tooth also appeared in the upper jaw . There was a large diastema between the front and rear teeth . The rear dentition consisted of four premolars and three molars in the upper jaw ; the first premolar was missing in the lower jaw. In individual cases, the first molar was reduced in the upper jaw. The anterior premolars were very small, while the posterior ones were almost the size of the following molars . The molars themselves were similar to those of the rhinoceros, but had less curved enamel folds . The enamel was very thick at 4 mm. In general, the molars were characterized by moderately high ( hypsodontic ) tooth crowns. Often the last molar had the largest dimensions and lengths of more than 10 cm. In general, however, the molars were very small in relation to the general size of the animals, the total length of the molar row was 40 cm and more.

Body skeleton

The cervical vertebrae attached to the skull reached an enormous size and were elongated in length, which caused the long neck of Paraceratherium . The length of the entire cervical spine exceeded that of the skull by one and a half to two times. The position of the joint surfaces on the vertebrae shows that the head was usually held horizontally, but could be swiveled out to the side. In addition, the first two cervical vertebrae were significantly shorter and wider and restricted vertical movement. Because of this, a permanent head posture similar to that of a horse or okapi with the neck bent upwards was hardly possible. The spinous processes of the first thoracic vertebrae were extremely long and therefore indicate a small hump just behind the neck, but also a musculature that was strong enough to hold the heavy head. On the side of the bodies of the vertebrae in front of the sacrum there were small, rounded cavities (pleurocoels or air sacs) that resemble those of the large sauropods , but it is unknown what they were filled with.

The limbs were very elongated and, like today's rhinos, were slightly angled under the body. The thigh bone reached lengths of 120 to 150 cm, and in contrast to the closely related rhinos, it also had less well-developed trochanters (large, small and third), which is possibly due to the enormous elongation of the entire bone and a parallel in the development of the elephant femora finds. The shin , on the other hand, was significantly shorter at 80 to 90 cm in length. In general, the humerus was 90 to 99 cm shorter than the spoke , which sometimes reached over 120 cm in length. The relationship between these two long bones suggests an origin of fast-moving ancestors. Both the front and rear legs ended in three toes, with the middle one being the largest. The metapodia were partially narrowed laterally and markedly elongated - the middle one could be up to 63 cm long - and the toe bones were also clearly flattened.

References

The most important finding areas of Paraceratherium in Eurasia

Significant sites can be found in the former Balochistan in what is now western Pakistan . The first finds from the Bugti Mountains also come from there. There are also very rich areas near Torghai in northwestern Kazakhstan , whose fossils are among the largest representatives of Paraceratherium , but remains of this animal species are also known in other parts of the country, for example from the Aktau Mountains in the southeast. Of particular importance is the Tsagan-Nor Basin in Mongolia , where most of the finds come from the Hsanda Gol Formation and include the most complete skull to date. Some of these finds also represent very large forms. The northern and northwestern provinces of China also contain numerous fossils, but they also include other forms of indricotheria. More recently, Paraceratherium finds have also been known from Turkey , some of which belong to very large representatives, for example from the Kızılırmak Formation in the Çankırı-Çorum Basin in the central and from the Güngörmez Formation in the Kağızman-Tuzluca Basin in northeastern Anatolia . The most westerly discovery sites so far are in Southeastern Europe , where remains of Paraceratherium occur in the Cuzăplac Formation in Romania , but individual bones have also been reported from Montenegro (Berane) and Bulgaria (Dragovištiza).

Paleobiology

height

Size comparison of Paraceratherium with rhinos as the closest related group and humans

Originally, a weight of up to 34 tons was assumed, but these values ​​were based on comparisons of proportions with today's rhinos and resulted in part from a first, but unsuccessful attempt at reconstruction by Henry Fairfield Osborn in 1923. However, these weight specifications have proven to be correct after more recent studies high, so that today a maximum weight of 15 to 20 tons is assumed, in extreme cases 24 tons, and smaller specimens only 7 to 9 tons. These studies are largely based on the comparison of individual bones, especially the skull and limbs, and also included numerous other animal species. Nevertheless, this weight information must only be viewed as an approximate estimate, as the indricotheria differ significantly in their body proportions from other unpaired ungulates . Because of these values, Paraceratherium is ultimately the largest known land mammal of all time. Compared to today's African elephant , which weighs around 4 to 6 tons, Paraceratherium is quite larger, but the largest elephant ever shot weighed around 10 tons and is now on display at the Smithsonian Institution . In contrast, the largest known proboscis had a weight comparable to Paraceratherium . The steppe elephant from the Pleistocene of Eurasia was up to 4.5 m high and weighed a good 14 tons, similar information is available for some representatives of the genus Palaeoloxodon . Deinotherium giganteum from the Miocene was 4.3 m shoulder height and 13 tons in weight. Possibly the 15 to 20 tons achieved by Paraceratherium represent the upper limit of the body mass of land-living mammals due to the special food utilization in the gastrointestinal tract. The specified size values ​​assume that Paraceratherium must have had sufficient thermoregulation . The subtropical climate in which it predominantly lived suggests that it had only a small coat of fur, similar to that of other very large mammals today, since a thick fur only stores excess body heat unnecessarily and dissipates it poorly. Furthermore, the bones around the ear entrance, especially the mastoid process and the paroccipital process , which both correspond to those of today's elephants, indicate that the auricle was possibly much larger than in comparison with today's rhinos and thus also contributed to regulation the heat balance. However, this interpretation is sometimes viewed with skepticism.

Locomotion

Hind leg of Paraceratherium

Most of today's extremely large mammals, such as elephants , rhinos and hippos , have adaptations to a cumbersome mode of locomotion ( graviportal ), which developed in adulthood due to a lack of pressure from predators , but which enables them to carry the high body weight. These are mainly found in the limbs, which are mainly characterized by long upper sections (upper arm and thigh bones) and shortened lower sections, especially the hand and foot bones. Especially in the metapodia (metacarpal and metatarsal bones) and the phalanges ( phalanges of fingers and toes), these shortenings are particularly noticeable, which limit very fast locomotion. In contrast, Paraceratherium had comparatively short upper and long lower limb sections, especially on the front legs, which indicate its origin from the fast-moving ( cursorial ) Hyracodontidae . The reduction in size of the lateral rays of the front and rear feet can be interpreted as a further sign, as this shows a tendency towards monodactyly. In contrast to real escape animals such as horses or deer , the phalanges are significantly shorter in length and thus resemble those of the clumsy rhinos and elephants, a similar development can also be observed in the large sauropods . From this it can be concluded that Paraceratherium was also restricted in its very fast locomotion.

Diet

The structure of the teeth, the long neck and the general size of the animals with a high head position make it probable that Paraceratherium specialized in soft plant foods with a low silica content and most likely ate leaves , twigs , buds or flowers ( browsing ). Microscopic abrasion marks on the molars show a typical pattern, which is similar to that of today's herbivores specializing in soft plant food. In addition, isotope analyzes of the molars, which were carried out on finds from China as well as from Pakistan, showed that Paraceratherium , based on the ratio of carbon isotopes to one another, almost exclusively fed on leaves. Its size enabled it to graze in the treetops of medium-high trees of its time, similar to what can be seen in today's giraffes in Africa. Since numerous animals that have recently specialized in leaf nutrition, such as the various species of rhinoceros that feed in this way, have a very mobile upper lip to support their food intake, this can also be assumed in Paraceratherium . Bony elevations as muscle attachment points in the facial skull as well as the nasal interior, which extends far back, indicate that the upper lip could even have had the shape of a small, short trunk, similar to the tapirs.

It can be assumed that in the case of Paraceratherium, analogous to today's and has also been proven in some extinct odd-toed ungulates, digestion took place in the rear intestinal tract (rectal fermenter). From this it can be concluded that the consumption of the food ingested was poorer than in the case of ruminants , which made it necessary for an animal to ingest large amounts of food every day. Compared to the amount of food that a modern elephant has to eat per day, Paraceratherium can be assumed to be at least as large .

Paleo-landscape

Live reconstruction of Paraceratherium, 1923

The size of the animals suggests that they were at home in open forest landscapes or tree savannas. Recent investigations at sites with Paraceratherium residues confirm this assumption. These open landscapes are associated with climatic changes during the Oligocene , which led to cooler and drier climates and thus contributed to the opening of the landscapes. Since Paraceratherium mainly consumed leaf food, the range of action of individual animals in such open landscapes must have been extremely large in order to achieve the necessary daily amount of food. It is unknown whether these herds formed, most odd ungulates live solitary with mother-calf relationships during rearing, only a few horse species form herd associations today, but this is a more modern adaptation to steppes and savannah landscapes that emerged from the Miocene . Adult representatives of Paraceratherium were probably due to the size hardly any natural enemies, but found some bones from the Bugti mountains in Pakistan bite marks, on a huge crocodile, Crocodylus bugtiensis , containing up to 11 was m long are returned and apparently occasionally attacked an animal.

Tribal history

Paraceratherium probably goes back to the pony-sized Forstercooperia as the basic form of the Indricotheria from the middle Eocene . The subsequent genera Juxia and Urtinotherium from the late Eocene and early Oligocene were also very primitive due to their different dentition morphology. In the early Oligocene, 37 million years ago, Paraceratherium was found for the first time , and one of the earliest finds is that of Nei-Monggol (China). The genus was distributed over large areas from West to East Asia and in a later phase also appeared in southeastern Europe. In the transition from the Upper Oligocene to the Lower Miocene around 23 million years ago it died out. The most recent historical records include those from the Bugti Mountains in Pakistan, ages from Lundo Chur, where new finds were made in the late 1990s, resulted in fission track dating of around 22.6 million years. This extinction was possibly accompanied by further climatic cooling, but also with the arrival of new, more competitive herbivores, such as the proboscis , which at that time reached Eurasia via the newly formed land bridge through the closure of the Tethys from Africa and possibly, similar to today's elephants their way of life were able to fundamentally change the landscapes.

Research history

Lower jaw of Paraceratherium, found by Forster Cooper and identified by him as a holotype of the genus
Ankle bone , foot bone and first cervical vertebra from Forster Cooper's 1913 publication describing the first description of Baluchitherium

The name Paraceratherium was introduced in 1911 by Sir Clive Forster Cooper (1880-1947). The first published bones of this animal, including a rear part of a lower jaw and individual upper jaw teeth, which were discovered during an expedition to Dera Bugti (Bugti Mountains) in Balochistan (Pakistan), had already been published by Guy Ellcock Pilgrim (1875–1943) in 1910 described as Aceratherium bugtiense . Pilgrim assigned more isolated maxillary teeth to the species Bugtitherium grandincisivum , but the full publication of the material did not take place until 1912. Pilgrim's interest in this region was aroused by the fossil discoveries made by William Thomas Blanford (1832-1905) in 1882. The earliest known finds, however, date from 1846, which a soldier named Vickary found, but could not be assigned for a long time due to their fragmented character. Forster Cooper led his own expedition to the area in 1910 and found an almost complete lower jaw, several vertebrae and long bones. On the basis of this material and with reference to Pilgrim's first brief mention, Forster Cooper published the first description of Paraceratherium bugtiense, with the lower jaw serving as the holotype of the genus. During another expedition in 1911 to the region, more precisely to Lundo Tschur, also Baluchistan, Forster Cooper discovered three more fragmented skulls in addition to a largely complete skull. The sites of Dera Bugti were only rediscovered in the mid-1990s, whereby the original site could be assigned to today's Chitawara formation .

The genus name Indricotherium is based on a description by Alexei A. Borissiak (1872-1944) from 1915, based on finds from Torghai in northern Turkestan (Kazakhstan). In addition to dentition fragments, these included a large part of the vertebrae and the bones of the musculoskeletal system. Since the complete naming of the species as Indricotherium asiaticum was not completed until 1923, this name was not recognized, as M. Pavlova had already described Indricotherium transouralicum in the previous year on the basis of finds, including a 63 cm long mandibular fragment with complete posterior dentition, from the same region.

The skull of Baluchitherium first found in 1922 by the "Third Asian Expedition" of the American Museum of Natural History
Reconstruction of Paraceratherium after Henry Fairfield Osborn from 1923, first version compared to the white rhinoceros above, second version compared to the Indian rhinoceros below

Further extensive bone material was discovered in 1922 during the Second Central Asiatic Expedition of the American Museum of Natural History under the direction of Roy Chapman Andrews (1884–1960) and Walter W. Granger (1872–1942) in the Tsagan-Nor Basin in Mongolia, including a lower jaw, an almost complete, but broken into more than 360 individual parts, 129 cm long skull and a humerus. These were described in the following year by Henry Fairfield Osborn (1857-1935) as Baluchitherium grangeri . The genus name Baluchitherium had already been introduced by Forster Cooper in 1913 because of several very large vertebrae that, in his opinion, did not match Paraceratherium , after the originally intended name Thaumastotherium osborni had been rejected for the newly described species, as it was already for an insect from the group of Schnabelkerfe had been awarded.

While the first finds from China date back to 1922 in the Ordos region of Inner Mongolia on the banks of the Yellow River , systematic investigations did not begin until the late 1950s and early 1960s and were in part connected with joint expeditions with Soviet paleontologists. Significant fossil remains came to light, all of which come from the northern part of China , especially from Xinjiang and Inner Mongolia, and include several skulls, including a 121 cm long specimen from the Dzungaria Basin , but also tooth remnants and parts of the postcranial Include skeleton. These finds were assigned to the genus Dzungariotherium , a very large representative. The first remains of Juxia and Urtinotherium , two older members of the Indricotheria in terms of tribal history, were also discovered at that time, especially from Inner Mongolia . A driving force behind these discoveries was the Chinese paleontologist Chow Minchen (1918–1996).

European finds came to light much later and are very rare overall. Fragments of maxillary molars come from a coal mine southeast of Berane in Montenegro and were published in 1957. Their characteristics spoke in favor of a reference to Indricotherium, as well as a last premolar of the upper jaw from a clay pit near Dragovištiza in Bulgaria . In addition, some maxillary molars came to light in the Cluj district in Romania , which were also placed under Indricotherium in their first publication in 1960 , but were later equated with Benaratherium . This genus of smaller representatives of the Indricotheria had been introduced five years earlier by LK Gabunia, citing a right branch of the lower jaw from Benara in Georgia . However, only a few finds can be assigned to it, including some wrist bones such as a moon bone , which was reported from the same site as early as 1951. Due to the extremely small amount of finds, however, the position of Benaratherium is very uncertain.

A first reconstruction was carried out by Osborn in 1923, but it was based on only a few finds from Mongolia and thus had a character too rhinoceros-like with clearly too short limbs and too short a neck. In the same year he made a more successful reconstruction, which he made on the basis of extensive finds from Mongolia and Balochistan. It was followed by the reconstruction attempt by Borissiak in the following year, which he carried out based on the Indricotherium finds and to which he added that of Baluchitherium for lack of a complete skull . His reconstruction differed a little from Osborn's second in terms of body proportions, but also came very close to the real appearance of Paraceratherium . A very comprehensive reconstruction that still defines the image today is that by Granger and Gregory from 1935, which was made with the help of the Mongolian finds and which was also followed by an extensive description of the finds. It should be mentioned that this reconstruction includes various finds that were divided into four different size classes by the two authors, since it came from several individuals with different body sizes.

Systematics

External system

The front teeth of four families of the Rhinocerotoidea , A: Amynodontidae ( Metamynodon ), B: Hyracodontidae ( Hyracodon ), C. Indricotheriidae ( Paraceratherium ), D: Rhinocerotidae ( Trigonias )

As a genus representative from the superfamily of the Rhinocerotoidea , Paraceratherium was related to today's rhinoceroses (Rhinocerotidae), but had no horns itself. When it was discovered, Forster Cooper initially assigned the species to the rhinos; Borissiak gave the name of the subfamily Indricotheriinae (Indricotherien), which he introduced in 1923 and which he also saw as a member of the rhinos at that time. In the same year Osborn suggested the names Baluchitheriinae or Paraceratheriinae, but both names are not valid. In 1939, however, Borissiak established the family name Indricotheriidae as the sister taxon of the rhinos, which was hardly recognized in the following years . Almost 30 years later, the group of Indricotheria was excluded from the Rhinocerotidae and assigned to the Hyracodontidae in 1967 due to their more complex and partially differently structured anterior teeth . The Hyracodontidae formed the rhinoceros' sister taxon within the Rhinocerotoidea at this time . The structure of the anterior dentition was used as the difference between the two groups. The real rhinos have a pair of plate-shaped incisor teeth in the upper row of teeth, while pointed, dagger-shaped teeth are formed in the lower jaw (so-called "chisel-tusk arrangement"). The Hyracodontidae, on the other hand, have a relatively variable front dentition. The Indricotherien resemble the rhinoceros, but also show dagger-like incisors in the upper dentition. The fact that a rudimentary fourth toe developed on the forefoot in basal indricotheria advocated a position within the real rhinos was largely rejected, as this feature also occurs in many primeval rhinoceros. The outsourcing of the Indricotheria from the rhinos was welcomed by a majority, but is not entirely undisputed. Due to the high variability of the Hyracodontidae, the Indicotheria was assigned an independent family status in the 2010s.

Within the Indricotheriidae the self-position of Indricotherium is the subject of a frequent discussion. While Baluchitherium was recognized very early as identical to Indricotherium and both were finally merged to Indricotherium in 1959 , the relationship to Paraceratherium was long unsolved. The difference in size between the smaller Paraceratherium and the much larger Indricotherium is remarkable . Other differences concern the shape of the lower jaw and the skull as well as the structure and number of teeth, especially the incisors. So Indricotherium had two smaller incisors between the upper large dagger-like tusks, while Paraceratherium did not. The position of the lower incisors also differs in their anatomical characteristics in both forms, since those of Indricotherium were significantly more upright. In spite of the small amount of fossil material in these parts of the body, it was discussed in the 1960s and 1970s whether the known deviations were due to different species or genera. However, in a revision of the Indricotherium in 1989 by Spencer G. Lucas and Jay C. Sobus , both forms were merged as belonging to one genus ( Paraceratherium ) and the differences were viewed intraspecifically as gender dimorphism , according to which Indricotherium may represent the male and Paraceratherium the female form. In addition to morphological and metric tooth comparisons, the basis for this was primarily several skulls from the Turpan Basin in China, all of which showed hardly any differences in variation. Nonetheless, many researchers advocate separating the two forms because of the differences that exist.

Internal systematics of the family of the Indricotheriidae according to Wang et al. 2016
 Indricotheriidae  


 Pappaceras


   

 Forstercooperia



   

 Juxia


   

 Urtinotherium


   

 Paraceratherium





Template: Klade / Maintenance / Style

In addition to Paraceratherium , Forstercooperia Juxia and Urtinotherium also belong to the Indricotheria. These differ largely in the higher number of teeth in the front dentition and are all smaller. The Borissiak of 1939 based on skull finds from near the Aral Sea described Aralotherium was also 1959 Indricotherien in the overall processing of the finds with Paraceratherium equal. Originally another genus was described with Dzungariotherium (the description was based on an almost complete skull from northwest China), but in the course of the taxonomic revision in 1989 it was included in Paraceratherium , which is not fully accepted. The taxonomic position of Benaratherium from Georgia , introduced by L. Gabunia in 1955, is unclear , as this genus could not be considered more closely in the revision carried out in 1989 due to fewer finds.

Internal system

Numerous different species have been described by Paraceratherium , due to the multiple names of the genus, many of these forms overlap. So were Baluchitherium grangeri, Indricotherium transouralicum and Indricotherium asiaticum or bugtiense Paraceratherium and Baluchitherium osborni early as synonymous recognized species. In the following, the eight species recognized today are briefly listed, of which the first four are recognized by the revision of the genus by Lucas and Sobus in 1989, the other four were not considered at that time or were subsequently described again:

  • P. bugtiense ( Pilgrim , 1908, 1910, 1912), originally Aceratherium , is the type species of Paraceratherium and was a smaller representative, weighing about 7.4 tons. The species is mainly proven in Pakistan.
  • P. transouralicum ( Pavlova , 1922), originally Baluchitherium and Indricotherium , was a large species, bulls weighed about 15 to 20 tons, cows probably only 9 to 11 tons. Significant detection areas are Kazakhstan and Mongolia. Besides P. bugtiense , this is the best researched species.
  • P. prohovori ( Borissiak , 1939), originally Aralotherium, was a smaller representative that weighed around 9 tons and was found mainly in eastern Kazakhstan. The species had a higher cranial roof and differs with individual anatomical differences in the lower jaw.
  • P. orgosense ( Qiu , 1973), originally Dzungariotherium, was a large species and reached approximately the size of P. transouralicum, but possibly also larger, since the teeth are up to 25% larger than in P. transouralicum, weights are given for large ones Individuals up to 24 tons. It is known, among other things, from an almost complete, 121 cm long skull find from the Djungarian Basin in Xinjiang in northwest China and had a pair of incisors in both the upper and lower jaw, which were significantly reduced in length, furthermore laterally widened premolars and an almost non-existent diastema.
  • P. zhajremensis Bayshashov , 1988 was a large species, possibly larger than P. transouralicum . It is known from several mandibular fragments from southeast Kazakhstan that differ morphologically from the other species, especially in the extremely deep bone of the mandible below the last molar.
  • P. sui Ye, Meng & Wu , 2003 was a smaller species, but was larger than P. bugtiense . The previously singular lower jaw from Fuhai in northwest China was very similar to that of the type species; but the symphysis of the lower jaw is clearly curved downwards. Sometimes the species is also put to Aralotherium .
  • P. yagouense Qiu, Wang & Deng , 2004 was a small species and comparable in size to P. bugtiense . It differs from other species in the reduction of the upper incisors and canines and higher-crowned molars, but the description is based on a skull of a non-adult animal that was found in the Linxia Basin in Gansu in northern China. There is also the possibility that P. yagouense belongs to the genus Turpanotherium , newly introduced in 2007 , for which a possible closer relationship with Urtinotherium is being considered.
  • P. huangheense Li, Zhang, Li, Li & Xie , 2017, was a large species. It was described on the remains of the upper and lower jaw from the Lanzhou Basin in the Chinese province of Gansu, near the Yellow River , where the Species name refers. The finds date to the Lower Oligocene and are around 31.5 million years old. The species is similar to P. bugtiense, but was significantly larger (length of the lower molar row 41.5 cm compared to 32.5 cm). The main differences to other forms are the details of the mandible and tooth morphology.

Chinese paleontologists also distinguish three other types.

  • P. tienshanense Chiu , 1962 was a large species, possibly as large as P. transouralicum or larger, but is only known from a fragmented mandible that originated in the Hami Basin in Xinjiang. The lower jaw was introduced as early as 1959 and assigned to the new species three years later. Sometimes the species is also listed in the genus Dzungariotherium .
  • P. lepidum Xu & Wang , 1978 was a smaller species and reached the dimensions of P. bugtiense, but is only known from a skull find from the Turpan Depression in Xinjiang . The find was associated with a complete cervical and thoracic spine, which can be reconstructed in an animal 7.2 m in length.
  • P. turfanense ( Xu & Wang , 1978), is a smaller species that is also part of Dzungariotherium . The find material includes a highly fragmented anterior skull, individual lower jaws and remains of the postcranial skeleton from the Turpan Depression.

literature

  • Walter W. Granger and William K. Gregory: Further notes on the gigantic extinct rhinoceros, Baluchitherium, from the Oligocene of Mongolia. Bulletin of the American Museum of Natural History 72, 1936, pp. 1-73.
  • Donald R. Prothero: Rhino giants: The palaeobiology of Indricotheres. Indiana University Press, 2013, ISBN 978-0-253-00819-0 , pp. 1-141.
  • Zhan-Xiang Qiu and Ban-Yue Wang: Paracerathere fossils of China. Palaeontologia Sinica 193 (New Series C, 29), 2007, pp. 1-396 (pp. 247-386 in English).

Individual evidence

  1. ↑ Michael P. Taylor and Mathew J. Wedel: Why sauropods had long necks; and why giraffes have short necks. PeerJ 1, 2013, p. E36.
  2. ↑ a b c d e f g h Walter W. Granger and William K. Gregory: Further notes on the gigantic extinct rhinoceros, Baluchitherium, from the Oligocene of Mongolia. Bulletin of the American Museum of Natural History 72, 1936, pp. 1-73.
  3. ↑ a b c d e Mikael Fortelius and John Kappelmann The largest land mammal ever imagined. Zoological Journal of the Linnean Society 107, 1993, pp. 85-101.
  4. ↑ a b c d e f g h i j k Donald R. Prothero: Rhino giants: The palaeobiology of Indricotheres. Indiana University Press, 2013, pp. 1-141 ISBN 978-0-253-00819-0 .
  5. ↑ a b Alexei A. Borissiak: About the subfamily Indricotheriinae Boriss. = Baluchitheriinae Osb. Zentralblatt für Mineralogie, Geologie und Paläontologie 18, 1924, pp. 571-575.
  6. ^ A b c Clive Forster-Cooper: On the skull and dentition of Paraceratherium bugtiense: a genus of aberrant rhinoceros from the lower Miocene deposits of Dera Bugti. Philosophical Transactions of the Royal Society of London (B) 212, 1924, pp. 369-394.
  7. ↑ a b c d e Clive Forster-Cooper: Paraceratherium bugtiense, a new genus of Rhinocerotidae from the Bugti Hills of Baluchistan - preliminary notice. The Anals and Magazine of Natural History 8, 1911, pp. 711-716.
  8. ↑ a b c d e f g h i Ye Jie, Meng Jin and Wu Wen: Discovery of Paraceratherium in the northern Junggar Basin of Xinjiang. Vertebrata Palasiatica 41 (3), 2003, pp. 220-229.
  9. ↑ a b c d e f g Zhan-Xiang Qiu and Ban-Yue Wang: Paracerathere fossils of China. Palaeontologia Sinica 193 (New Series C, 29), 2007, pp. 1-396 (pp. 247-386 in English).
  10. ↑ a b c Demberelyin Dashzeveg: A new Hyracodontid (Perissodactyla, Rhinocerotoidea) from the Ergilin Dzo formation (Oligocene Quarry 1) in Dzamyn Ude, Eastern Gobi Desert, Mongolia. American Museum Novitates 3178, 1996, pp. 1-12.
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  13. ^ A b P. Martin Sander, Andreas Christian, Marcus Clauss, Regina Fechner, Carole T. Gee, Eva-Maria Griebeler, Hanns-Christian Gunga, J¨urgen Hummel, Heinrich Mallison, Steven F. Perry, Holger Preuschoft, Oliver WM Rauhut, Kristian Remes, Thomas T¨utken, Oliver Wings and Ulrich Witzel: Biology of the sauropod dinosaurs: the evolution of gigantism. Biological Reviews 86, 2011, pp. 117-155.
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