#Plesitocene

[prophetpedia]

"SIBERIAN UNICORN" THAT LOOKED MORE LIKE A HAIRY RHINOCEROS, ROAMED THE EARTH AS RECENTLY AS 29,000 YEARS AGO!

“SIBERIAN UNICORN” THAT LOOKED MORE LIKE A HAIRY RHINOCEROS, ROAMED THE EARTH AS RECENTLY AS 29,000 YEARS AGO!

The ‘siberian unicorn’ (Elasmotherium) reproduction sculpture. Elasmotherium was a genus of large rhinoceros endemic to Eurasia during the late pliocene through the pleistocene existing from 2.6 Ma to at least as late as 39,000 years ago in the late plesitocene. A more recent date of 26,000 BP is considered less reliable. Three species are recognized. The best known, E. Sibiricum, or Siberian…

[sixlegnag]

Creature Feature #2: genus Sivatherium

Happy end of April, all. This month, we’ll touch upon some charismatic megafauna from the past.

[beautifully painted reconstruction (c) Jaime Chirinos]

A Genus of Gigantic Giraffes

Sivatherium. Maybe you’ve heard of them, maybe you haven’t, but if you saw any one of them, it would certainly check off all the boxes on the ‘classic Pleistocene megafauna’ criteria sheet. Massive? Yes. Ornate, and just otherworldly enough to raise the hairs on the back of your neck? Yes and yes.

The genus consists of three species: S. hendeyi, which only survived into the Pliocene and was found in South Africa, S. maurusium, which made it to the early Pleistocene and dwelled across a larger range in Africa, and the type species, S. giganteum, which hailed from the Himalayan foothills in India and survived up to the early Pleistocene as well.

A Unique Anatomical Bouquet

All three species were considerably more robust, and both shorter-necked and shorter-legged than the two modern giraffids. S. giganteum has been described as and indeed restored as moose-like in proportions, and its wide, flaring ossicones certainly encourage the admittedly outdated comparison. Unlike modern giraffids, which sport only modest anterior and posterior pairs of ossicones in both sexes, male sivatheres boast large, palmate or branching rear ossicones. Imagine the lovechild of and ox and an okapi wearing the ornaments of a deer, and you will have the gist of it. The gist of it does not do the genus justice, however. They were truly built like nothing which walks this earth today, a fact which has made determining their live weights difficult, an issue compounded by lack of fossil material to make inferences from. S. giganteum is known from cranial, cervical, and partial limb elements, while the other two are known from equally fragmentary remains. The three are told apart by geographic age and teeth.

Initially, it was believed S. giganteum could weigh as much as an elephant, but more recent estimates downsize it considerably. Conservative estimates place the weight at less than 1,900 kg, but a large bull would certainly have tipped the scales above that weight. Depending on the actual (but currently unknown) dimensions of the animal’s torso and true soft tissue bulk, it may have weighed more, but certainly not as much as any species of elephant. However, the minimum estimate still leaves S. giganteum as the most likely contender for history’s largest ruminant by weight. It loses the contest in height to other giraffids, but nevertheless, it stood over two meters high at the shoulder - no small animal. The world’s tallest horses hit the same numbers, but Sivatherium’s unique proportions leave it difficult to picture.

Mysterious Life Histories

As you might expect from their proportions, they were not dedicated browsers like either extant giraffid - they lack the long necks. Based on analysis of tooth wear, it appears that both African species were mixed feeders, whose diets were dictated by the seasons.S. giganteum looks to have been a grazer, like a modern rhinoceros.

Beyond that, little is known about the lives of sivatheres. Fossil deposits imply they lived in herds; S. hendeyi material has been recovered from sites that are consistent with mass death from sudden flooding. Restorations have included various soft-tissue add-ons in the form of small trunks, dewlaps, and long tongues, but evidence for any of these is lacking. Climate change likely signaled the curtain call for all three species. As sub-Saharan Africa dried and the grasslands expanded, the African sivatheres failed to adjust to the loss of leafy vegetation from their diet. While S. giganteum evolved to handle a high grass diet, it is likely that environmental changes relating to the tectonic upheaval throughout its range did away with it, too.

References

Basu C, Falkingham P L, Hutchinson J R. 2006. The extinct, giant giraffid Sivatherium giganteum: skeletal reconstruction and body mass estimation. Biol. lett. 12(1): np.

Churcher C S. 1974. Sivatherium maurusium (Pomel) from the Swartkrans austalopithecine site, Transvaal (Mammalia: giraffidae). Annals of the transvaal museum. 29(6): 65-70.

Franz-Odendaal T and N Solounias. 2004. Comparative dietary evaluations of an extinct giraffid (Sivatherium hendeyi) (mammalia, giraffidae, sivatheriinae) from Langebaanweg, South Africa (early Pliocene). Geodiversitas. 26(4): 675-85.

Geraads D. 1996. Sivatherium (giraffidae, mammalia) if the latest Pliocene of Ahl al Oughlam (Casablanca, Morocco) and the evolution of the genus in Africa. Palaontologische zeitschrifte. 70(3): 623-9. Translated by Duran J, 2005.

Khan A A, Khan M A, Iqbal M, Akhtar M, Sarwar M. 2011. Sivatherium (artiodactyla, ruminantia, giraffidae) from the upper siwaliks, Pakistan. J. anim. plant sci. 21(2): 202-6.

Klein R G. 1982. Patterns of ungulate mortality and ungulate mortality profiles from Langebaanweg (early Pliocene) and Elandsfontein (middle Plesitocene) south-western Cape Province, South Africa. Ann. s. afr. mus. 90(2): 49-94.

Robinson C A. 2011. Giraffidae. Paleontology and geology of Laetoli: human evolution in context. ed. Harrison T. 339-63.