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Paraceratherium - One of the Largest Land Mammals Ever! Facts and Information

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Introduction / Physical Description

Weighing in at 17 tons and a shoulder height of 16 feet, Paraceratherium is one of the largest land mammals to EVER live! These animals roamed Asia, Western Europe, and Asia in the Oligocene time period.

Paraceratherium was a type of giant hornless rhino with a long giraffe-like neck. They were herbivoures that were adapted at eating vegetation from trees. They were so large; they could graze treetops that other animals couldn't reach. Their teeth were designed for picking foliage off of trees and the nasal area of their skulls show they had some type of trunk (Prothero, 2013, p. 88). It was probably similar to the short prehensile trunk of a Taper. This trunk would also aid in picking foliage from trees. Finally, Prothero indicates these large animals would have been similar to elephants in that they would have problems regulating their heat. Because of this, Prothero suggests Paraceratherium fed mainly at night and also had large ears to dissipate heat (Prothero, 2013, p. 100 & 88).

The Oligocene was a cool and dry period of time. Asia was full of scrublands with sparce woodlands dotted here and there. Paraceratheriums would have had a vast range, and would have traveled miles and miles from woodland to woodland eating the tree tops.

Size

Although Paracerathriums were giant, they were not the largest land mammals. Larramendi reconstructed some of the largest elephants and found one to be slightly larger than this giant rhino (2015). The elephant is Palaeoloxodon namadicus of the Pleistocene. Although the fossils of this animal are few and fragmentary, based on the available material, Larramendi puts Palaeoloxodon at a weight of 22 tons and a shoulder height of 5.2 m (17 feet). He puts a large Paraceratherium transouralicum specimen at 17 tons and a shoulder height of 4.8 m (16 feet). This officially makes Paraceratherium the world's second largest land mammal to ever live.

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The Discovery of Paraceratherium

The First Discoveries - Pakistan and Kazakhstan

In 1846, fragmentary fossils of these giant Paraceratheres were first discovered in the Dera Bugti area of what is now Pakistan. At the time, these fragments were unidentifiable. Soon after though, around the turn of the century, British paleontologists including Pilgrim and then Forester Cooper explored the Dera Bugti area and found bone beds of Paraceratherids. This area is where the valid genus and species Paraceratherium bugtiense comes from.

Around the same time, in the early 1900's, Paracerathere fossils were also found by Russian paleontologists in Kazakhstan, including a nearly complete skeleton which was named Indricotherium transouralicum (which is now Paraceratherium transouralicum).

Remarkable Discoveries - The Mongolian Expeditions of the 1920's

Many of the better specimens came from the Gobi Desert in Mongolia. Starting in 1922, Osborn of the American Museum of Natural History sent Roy Chapman Andrews (A real life Indiana Jones) on large expeditions into the Gobi Desert of Mongolia. Accompanying Chapman was renowned paleontologist Walter Granger. Among the many fossils found were exceptional remains of Paraceratherids. They appeared to be relatively common in Mongolia. In Chapmans 1932 book, he talks about fossil hunting with field glasses. In the mornings, he would simply walk to the top of ridges, scan the badlands with binoculars, and spot white bones eroding out of the formations. Andrews also said huge bones and fragments of these giant animals were scattered over the floors of most ravines.

Among the countless bones, including partial specimens, were amazing discoveries. One was the 1922 discovery of one of the most complete Paracerathere skulls (AMNH 18650). Another find was most unusual; four giant Paracerathere legs sticking straight up (Shown in the image above). It appears the Indricothere became trapped in quicksand and died. The stuck legs were forever preserved in their life position. It kind of reminds me of the Mammoth Site, where mammoths are fossilized in their trapped positions in the mud.

Modern Discoveries

Today, Paracerathere remains are still being found in Mongolia, Kazahkstan, and Pakistan, as well as other locations throughout Asia.
Paraceratheres are also found on the Anatolian Peninsula of Turkey (Sen et al. 2011).
The western most occurrence comes from Western Europe. Fragments have been found in Georgia, Serbia, Bulgaria and Romania (OYAL, 2016).
Recently, in 2021, a new species from China was described: P. linxiaense.

Additional historical images are in the "Additional Images" section toward the bottom of this page.

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The many names of Paraceratherium

When the first fossils were discovered in the mid to late 1800's in the Dera Bugti hills of what is now Pakistan, the fossil samples were very fragmentary. The first description came from Pilgrim and it was based off skull fragments which looked like a fossil rhinoceros called Aceratherium, the "Hornless Beast." Since he couldn't tell any difference, he named it Aceratherium bugtiense. Later when Forster Cooper went to the Bugti region and collected better specimens, he realized the skull was different from Aceratherium. As he states in his 1911 paper, it has an "unusual position and shape of the two lower incisors." He goes on to elaborate further on the downturned incisors and knew it was slightly different from Aceratherium, so he named it Paraceratherium bugtiense, which means "Near Aceratherium" or "Near the Hornless Beast."

Since it's discovery and naming, there have been many other specimens found throughout Asia. Many of the paleontologists that discovered these newer specimens named them different genera based on small differences. Over time, this genus became, what paleontologists call, "over-split," where one genus is broken into many different genera. It was given names such as Baluchitherium, Indricotherium, Dzungariotherium, and others. Today, most paleontologists think the variation in the skulls simply show natural variation, such as sexual dimorphism, age variation, individual variation, and population differences. For the most part, they have "un-split" all the genus names back into Paraceratherium. I say for the most part, because some paleontologists think there should be at least a couple different genera of Paraceratherium.

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Origins, Evolution, Distribution, and Species

When most people think of prehistoric rhinos, they think of the giant horned Elasmotherium (Siberian Unicorn Rhino) and the dual horned Woolly Rhino. However, there was so much more. Rhinos have an immense diversity in the past, many which did not resemble today's rhinos, and many that did not have horns.

Unfortunately, Paraceratheres and other early rhinos have a very fragmentary fossil record, as a result, their evolution still needs to be completely sorted out. Below are two versions of their evolution.

The Classic Version of the Origins and Evolution:
This version worked well until new discoveries in 2016.

Until recent discoveries, it was though these giant rhinos branched off from a family of rhinoceros called hyracodonts in the Middle Eocene. Hyracodonts were dog sized, hornless rhinos with long legs adapted for running. They superficially resembled a small horse. In the middle Eocene, two genera called Forrestercooperi and Pappaceras branched off. These animals looked a little like small Paraceratheriums, and over time different genera arose Juxia, Urtinotherium, and Paraceratherium. Each of these successive genera became larger and larger, and their skulls and teeth became more specialized. The final form is the giant rhinoceros, Paraceratherium. All of these above genera are placed in the Indricotheriinae subfamily, which is why the term Indricothere is often used for these type of animals.

The New Version of the Origins and Evolution:
This version takes into consideration the 2016 discoveries

In 2016, fossils of the earliest occurrence of a new specimen called Pappaceras meiomoenus was discovered and described from the Early Eocene (Wang H. et al. 2016). These fossils also contained a much more complete skull than older Pappaceras specimens. The better fossils pushed back the dates of the appearance of Pappaceras by millions of years. This earlier appearance and the ability to analyze a more complete skull caused a revision of the family tree. In the end Wang H. et al. published a new phylogenetic relationship of the early rhinoceros.

What this means for the giant rhinos is they are not as closely related to hyracodonts as once thought. Also, the genera Forrestercooperia and Pappaceras are not direct ancestors of the giant rhinos, but a sister family. Finally, they removed the Indrictotheriidae subfamily, and made Paraceratheriidae its own family. This family has two subfamilies, Forrestercooperiinai and Paraceratheriinae. The new subfamily of Paraceratheriinae now has 3 genera of giant rhinos, Juxia, Urtinotherium, and Paraceratherium. This is easier shown in the table below that Wang H. et al. painstakingly produced!

The 3 Paracerathere genera

The 3 genera in the Paraceratheriinae subfamily are Juxia, Urtinotherium, and Paraceratherium. These Paracerathere (formerly Indricothere) genera are briefly discussed below.

Juxia is the earliest Paracerathere and is found in Middle Eocene exposures in Mongolia, China, and India. At around the size of a horse, It was a smaller and more lightly built version of Paraceratherium. Three generally accepted species which are J. sharamurenesis, J. micracis, and J. shoui.

Urtinotherium is a Late Eocene to Early Oligocene Paracerathere that is also found in Mongolia and China. This genus is around the size of a small Paraceratherium and has a skull and teeth that are more similar to Paraceratherium. The generally accepted species are U. parvum, U. incisivum.

Paraceratherium is the final Oligocene genus that reached huge proportions. They are found in Eastern Europe, Turkey, and throughout Asia. There are many claimed species based from fragments, some of which are probably not valid. Some of the possible species include P. bugtiense, P. transouralicum, P. orgosensis, P. haungheense, P. granger, and P. lepidum. All of these species are found sometime from the Early Oligocene to the Late Oligocene.

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Extinction – Are Gomphotheres to Blame?

Unlike most mammals, including the Oligocene Arsinoitherium, climate change and the resulting disruption of habitat may not have been totally responsible for Paraceratherid extinction.

These giant rhinos appeared in the Eocene when the climate was much warmer and wetter. They thrived on the plentiful trees in the forested environments. Toward the end of the Eocene and beginning of the Oligocene for the first time in over 100 million years, global temperatures cooled enough that glaciers and ice caps formed (Prothero, 1994). This dropped sea levels and changed ocean circulation patterns. The cooler Earth became more arid. In Asia, semi-tropical forested environments that Paraceratherids lived changed to scrublands and savannah type environments with sparse wooded areas. Despite this, Paraceratherids seemed to have thrived throughout the Oligocene. They most likely roamed large distances moving between isolated woodlands eating from the canopies of trees. The changing climate and shift in ecosystems can't be responsible for their extinction.

So what did them in? There must have been other factors. One factor that Putshokov presents in a 2001 publication is elephants. Asia saw an "invasion" of early elephants from Africa toward the end of the Oligocene and beginning of the Miocene (Putshokov, 2001). These early elephants, mainly the Gomphotheres, were mixed browsers and were well suited for eating hard materials, including bark from trees. They would have been in the same environments in which they lived, stripping the trees of their bark and killing them (Putshokov, 2001). We know elephants today dramatically change the environment they live in, converting forests into grasslands. Prehistoric elephants would have done the same thing. The sparse woodlands that Paracerathrids survived would have been turned into scrublands. With their food source gone, their numbers would have dwindled. It is probably no coincidence that Paraceratherids disappeared soon after Gomphotheres moved into Asia.

In addition to the impact from Gomphotheres, large carnivores also migrated from Africa to Asia in the Early Miocene. These large carnivores, such as the giant Hyainailurus and Amphicyon, would have been able to easily prey on young Paraceratherids (Prothero, 2013, p. 121). This new threat would have further hurt dwindling populations of Paraceratherids.

Although Paraceratherids survived the changing climate and ecosystems, probably due to their vast range, they did not survive the pressures from new mammals migrating into Asia during the beginning of the Miocene.

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Works Cited:

Andrews, Roy Chapman. (1932). The new conquest of central Asia : a narrative of the explorations of the Central Asiatic expeditions in Mongolia and China, 1921-1930. American Museum of Natural History, New York. DOI: 10.5962/bhl.title.12200.

Forster-Cooper C. (1911). LXXVIII.—Paraceratherium bugtiense, a new genus of Rhinocerotidae from the Bugti Hills of Baluchistan.—Preliminary notice. Annals and Magazine of Natural History Series 8. 8 (48): 711–716. Archived Book Here.

Janis, Christine (1982). Evolution of Horns in Ungulates: Ecology and Paleoecology. Biological Reviews 57: 261- 318. DOI: 10.1111/j.1469-185X.1982.tb00370.x

Larramendi, A. (2015). Shoulder Height, Body Mass and Shape of Proboscideans. Acta Palaeontologica Polonica. 61. dx.doi.org/10.4202/app.00136.2014.

OYAL, Nese. (2016). Description, Evolution and Paleogeography of the Giant Rhinoceros (PARACERATHERIUM, RHINOCEROTOIDEA, MAMMALIA) from the Olicogene of the Çankiri-Çorum Basin. DIO: 10.13140/RG.2.2.30670.87366.

Prothero, D.R. (2013). Rhinoceros giants: the paleobiology of Indricotheres. Bloomington: Indiana University Press. Link to Book on Amazon here.

Prothero, D.R.. (1994). The Late Eocene-Oligocene Extinctions. Annual Review of Earth and Planetary Sciences. 22. 145-165. DOI: 10.1146/annurev.ea.22.050194.001045.

Putshkov, P.V. (2001). 'Proboscidean agent' of some Tertiary megafaunal extinctions. Schmalhausen Institute of Zoology, Kiev, Ukraine - in: The World of Elephants. International Congress, Rome (PDF HERE).

Sen, Sevket & Antoine, Pierre-Olivier & Varol, Baki & Ayyildiz, Turhan & Sözeri, Koray. (2011). Discovery of the giant rhinocerotoid Paraceratherium Forster Cooper 1911 (Mammalia, Perissodactyla) and other vertebrates in the Oligocene and middle Miocene deposits of the Igdir-Kagizman Basin, Eastern Turkey. DOI: 10.1007/s00114-011-0786-z

Wang, Hai-Bing & Bai, Bin & Meng, Jin & Wang, Y-Q. (2016). Earliest known unequivocal rhinocerotoid sheds new light on the origin of Giant Rhinos and phylogeny of early rhinocerotoids. Scientific Reports. 6. 39607. DOI: 10.1038/srep39607.

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Recommended Prehistoric Mammal Books:

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Additional Images of Paraceratherium

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