Showing posts with label Mongolia. Show all posts
Showing posts with label Mongolia. Show all posts

Saturday, March 26, 2016

Paleo File: Bagaraatan


         Bagaraatan, which is mongolian for “little hunter”, was a small carnivorous theropod dinosaur. Polish Paleontologist, Halszka Osmólska discovered the remains of the animal in the Nemegt Formation of Mongolia 1996. Although the name might seem odd, it is the phylogenetic categorization that makes this organism an oddity.


Art and Copyright belongs to Robinson Kunz
          Halska Osmólska never pursued her findings to the phylogenetic level and left it to other scientists to decide on the fragmentary remains; A Lower Mandible, the upper legs, pelvis, and caudal vertebrae. Scientists have found three possible groups the animal may belong to; Holtz suggested a Tyrannosauroid, Coria a Troodontid, and Rauhut a Maniraptoran. However, despite the differing opinions and confounding evidence, the phylogenetic grouping so far agreed upon is Tyrannosauroidea. More fossils are needed before a concrete classification can be reached, or an appropriate reconstruction of the animal in life.

Material referred to Bagaraatan
References:

"BAGARAATAN : From DinoChecker's Dinosaur Archive." Dinochecker RSS. Dinochecker, n.d. Web. 24 Mar. 2016. <http://www.dinochecker.com/dinosaurs/BAGARAATAN>.

"Bagaratan." Wikipedia. Wikimedia Foundation, n.d. Web. 24 Mar. 2016. <https://en.wikipedia.org/wiki/Bagaraatan>.

Osmolska, H. (1996). "An unusual theropod dinosaur from the Late Cretaceous Nemegt Formation of Mongolia". Acta Palaeontologica Polonica 41; 1-38

"Bagaraatan." Bagaraatan. Prehistoric Wildlife, n.d. Web. 24 Mar. 2016. <http://www.prehistoric-wildlife.com/species/b/bagaraatan.html>.

Thursday, March 17, 2016

Paleo File: Alectrosaurus

         The fossil record, although expansive and bursting-from-the-seams with material, is rather fragmentary. This can be observed time and time again with discoveries so fragmentary proper names are impossible to be attributed. The tomb that is Mongolia is a great reservoir of fossils, many quite well-preserved; however, along with the well-preserved specimens comes the fragmentary ones. Alectrosaurus is one of those fragmentary finds that struggles to shed light on the ecosystems of the prehistoric world, and of course Mongolia as well.



Only the right hindlimb was found on April 25th, 1925, by the Third Asiatic Expedition of the American Museum of Natural History. This find was not the first nor the last and a week later assistant Paleontologist, George Olsen, (the discoverer of the first specimen) found more material on the fourth of May. Nearly one hundred feet away from the initial specimen, he discovered a right humerus, two incomplete manual digits, and four fragmentary caudal vertebrae. These finds were sent back to the museum and prepared; however, more material was uncovered some time later. Fossils were then found in Outer Mongolia which included skull and shoulder fragments. Enough material to suggest how the animal may have appeared in life (Thanks to the laws of symmetry), still more material is needed to get a better picture of this animal.

Art and Copyright belongs to Sergey Krasovskiy
                 The material that was found suggests a Tyrannosauroid theropod of medium size and moderate build. Alectrosaurus may have reached lengths of up to twenty feet. Unlike other Tyrannosauroids, the superfamily leading to more advanced groups like Tyrannosauridae, the lengths of the tibia and femur are rather similar. The formation in which Alectrosaurus was found, called the Iren Dabasu Formation, suggests it may have lived in an area that also housed animals like Gigantoraptor, Bactrosaurus, and Gilmoreosaurus.

Art and Copyright belongs to Prehistoric Wildlife

Copyright belongs to BBC

Works Cited:

Holtz, Thomas R. Jr. (2011) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2010 Appendix.

Loewen, M.A.; Irmis, R.B.; Sertich, J.J.W.; Currie, P. J.; Sampson, S. D. (2013). Evans, David C, ed. "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans". PLoS ONE 8 (11): e79420. doi:10.1371/journal.pone.0079420

Rothschild, B., Tanke, D. H., and Ford, T. L., 2001, Theropod stress fractures and tendon avulsions as a clue to activity: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 331-336.

"Alectrosaurus." Alectrosaurus. Prehistoric Wildlife, n.d. Web. 17 Mar. 2016.

"Alectrosaurus Olseni - Palaeocritti - a Guide to Prehistoric Animals." Alectrosaurus Olseni - Palaeocritti - a Guide to Prehistoric Animals. Palaeocritti, n.d. Web. 17 Mar. 2016.

"Alectrosaurus Olseni - Palaeocritti - a Guide to Prehistoric Animals." Alectrosaurus Olseni - Palaeocritti - a Guide to Prehistoric Animals. Palaeocritti, n.d. Web. 17 Mar. 2016.

"Fossilworks: Alectrosaurus Olseni." Fossilworks: Alectrosaurus Olseni. Fossil Works, n.d. Web. 17 Mar. 2016.

Wednesday, January 20, 2016

Paleo File: Deinocheirus

  • Name means: “Wonderfully Terrible Hand”
  • Height: 3-6 meters
  • Weight: 9 tons
  • Length: 13 meters
  • Region: Gobi Desert, Mongolia

(Copyright: Andrey Atuchin)

         One of arguably the oddest dinosaur discoveries to date, Deinocheirus, has been an enigma for over 50 years. Ever since its discovery Deinocheirus, which translates from Latin to “Terrible Hand”, has captured the imagination of those with the right resources to know about it. Despite its enigmatic nature in the fossil record, Paleontologists were finally able to put the mystery of how the animal looked to rest in 2014.


(Copyright: Public Domain Wikipedia)

         The first fossils of Deinocheirus consisted of the massive forearms (only missing the claws on the right hand), the complete shoulder girdle, three dorsal vertebrae, five ribs, and the gastralia (commonly referred to as belly ribs). Polish Paleontologist, Zofia Kielan-Jaworowska, found these remains in the Nemegt Formation of the Gobi Desert, Mongolia on July ninth 1965. Zofia, along with Paleontologist Rinchen Barsbold, were part of the 1963–1965 Polish-Mongolian paleontological expeditions when they found the remains. The arms were classified as a Theropod dinosaur, and considering the lack of extraneous material, the scientists had no idea as to what the animal looked like until the year 2012. In 2012, Phil R. Bell, Philip J. Currie, and Yuong-Nam Lee issued their findings of new Deinocheirus material. These scientists found more gastralia fossils in the same dig site of the prior team. What they found explained the scarcity of material from the dig site. They found bite marks on the gastralia that matched the teeth of the Tyrannosauid, Tarbosaurus, with which Deinocheirus shared its ecosystem. Then in 2013, Lee, Barsbold, Currie, and colleagues announced the discovery of two new Deinocheirus specimens at the annual Society of Vertebrate Paleontology conference. This find gave great insight into what the animal looked like and where the animal fit in, phylogenetically. Due to fossil poachers, much of the identifiable parts of the skeletons were gone; the heads, feet, and hands were all stolen. A short time later, word of the skull and hands making their way to the fossil black market helped the European museum acquire them. This skull solidified not only the identity of this bizarre dinosaur, but also nailed the final nail in the coffin to the secret of Deinocheirus.

(Copyright: Public Domain: Wikipedia)
(Copyright: Public Domain Wikipedia)

            Deinocheirus is known by only one species, coined Mirificus, which translates to ‘wonderful’. It is now known that Deinocheirus was a giant amongst Ornithomimids. It towered at a height of 3.5 to 6 meters and measured a length of 11 meters, and could have weighed as much as 6 tons; Deinocheirus is the largest example of Ornithomimosauria that currently exists. The fossils of Deinocheirus suggest omnivory, due to evidence of piscivory and herbivory found in its stomach. Gastroliths (stones swallowed to aid in digestion) and fish scales were found in the stomach cavity of the skeleton and points to a varied diet of plants, fish, and probably other types of vegetation like fruit. Deinocheirus lived during the Late Campanian/Early Maastrichtian of the Cretaceous Period of what is now Mongolia.

(Copyright: Public Domain Wikipedia)

       Deinocheirus’ relatives are Garudimimus and Beishanlong. All three of these animals make up their own family within Ornithomimosauria and share the characteristics of a slower mode of life and a bulkier build than most other Ornithomimids. Deinocheirus, being an omnivore, would have had little competition from its contemporaries with the only exception being Therizinosaurus; both shared similar characteristics and were likely omnivorous. 

      Deinocheirus shared its ecosystem with a wide range of animals like Tarbosaurus, Pinacosaurus, Saichania, Protoceratops, Oviraptor, Velociraptor, and more. Evidence strongly suggests that the first specimen met its end from a Tarbosaurus (a Mongolian relative of Tyrannosaurus) and, as such, must have been a predator of Deinocheirus. Alioramus, another relative to Tyrannosaurus, may have preyed on Deinocheirus as well. Deinocheirus lived in a place that, at the time, was home to vast swamps and river ways, which would have provided it a niche that most other herbivores and even most carnivores had yet to adapt to; Omnivory.

(Copyright: Art belongs to Geocities)

     The Paleontologists that found Deinocheirus quickly determined it to be a Theropod; however, what kind was impossible to know. At the time, 1965, the scientists thought the arms belonged to a massive carnivorous carnosaur-like animal. At this point in history, most carnivorous theropods were thrown together into one phylogenetic ‘unnatural’ grouping called Carnosauria (This has since been revoked due to further variation amongst the Theropoda family tree). Deinocheirus became identified as something other than a carnivorous Theropod only after the gastralia material had been found. The discovery of Therizinosaurid dinosaurs, like Nothronychus and Segnosaurus, made the possibility of herbivorous theropods a reality. Paleontologists had been debating whether Deinocheirus was an Ornithomimid or a Therizinosaurid until the latest skeletal discovery made the decision. Even though science knows more about Deinocheirus than ever before, aspects of its paleobiology and habits are still unknown and only more material will unearth the secret of Mongolia.

(Copyright: Art belongs to Geocities)

(Copyright: Scale belongs to PrehistoricWildlife)
Works Cited

"Deinocheirus." Wikipedia. Wikimedia Foundation, n.d. Web. 03 Nov. 2015.

Yong, Ed. "Deinocheirus Exposed: Meet The Body Behind the Terrible Hand." Phenomena Deinocheirus Exposed Meet The Body Behind the Terrible Hand Comments. National Geographic, 22 Oct. 2014. Web. 03 Nov. 2015.

"Deinocheirus." Deinocheirus. PrehistoricWildlife, n.d. Web. 03 Nov. 2015.

Perkins, Sid. "Fossils Reveal 'beer-bellied' Dinosaur." Nature.com. Nature Publishing Group, 22 Oct. 2014. Web. 03 Nov. 2015.

Tuesday, December 29, 2015

Paleo File: Alioramus

  • Pronunciation: (Ah-Lee-Oh-Ram-Us)
  • Meaning: "Different Branch"
  • Length: 19ft
  • Height: 6ft
  • Diet: Carnivorous
  • Time: Cretaceous (75 MYA)
  • Region: Asia (Mongolia)

Alioramus, a midsized tyrannosaur from the Late Cretaceous (72-66MYA) of Mongolia, is yet another dinosaur grounded in mystery due to scant remains. However, even though this is the case, many details about the animal can be extrapolated from the few remains that have been uncovered.

Alioramus Skull Reconstruction

         A Soviet-Mongolian expedition to the Gobi Desert of Mongolia in the early 1970s uncovered the remains of Alioramus, but it was not until 1976 that soviet paleontologist, Sergei Kurzanov, identified the remains. Kurzanov found the animal to be a tyrannosaur and named it Alioramus remotus, which translates to “Removed Other Branch”. Kurzanov named his find after the fact that the animal contained characteristics of no other animal of the family it belonged to. Kurzanov placed the animal in the general superfamily Tyrannosauroidea. Alioramus remained a very partial species with only fragmentary skull material having been found, until another much more complete find was discovered in 2001 by Julia Clarke on another expedition to Mongolia with the American Museum of Natural History and Mongolian Academy of Sciences. This new species was named Altai, in homage to the Altai Mountains in Mongolia in 2009. This new find consisted of a nearly complete skull, missing just a few minor bones, a complete neck, large segments of the back, sacrum, tail, a nearly complete pelvis, and most of the hind limbs. Although still rather fragmentary, the animal can now be rather accurately reconstructed with a proper body.

Alioramus Reconstruction (Art and Copyright belongs to Fred Wierum; FredtheDinosaurman on DeviantArt)

          What is known of Alioramus is scant, but what is known is rather interesting. Alioramus is known only from juvenile specimens, and as such, the adult size cannot be fully determined. However, the juvenile specimens uncovered suggest an length of approximately 15-19ft; juvenile Alioramus would have stood as tall as an adult human. The most distinguishing features of Alioramus is its skull. The animal had a very gracile skull much more elongate than the majority of other known Tyrannosaurs (minus Nanotyrannus), not only this, but the skull sported a series of about 5-6 small hornlets that ran along the snout and jutted upwards about 1-2 inches. Due to the fact that the remains only represent juvenile specimens, scientists had hypothesized that Alioramus might be the juvenile of the larger tyrannosaur that it shared its environment with; Tarbosaurus. However, juvenile specimens identified to belong to the genus Tarbosaurus with differing characteristics to Alioramus suggest that the animal was a different species altogether. Slender features and legs like that of an Ornithomimosaur, suggests that Alioramus would have preyed upon smaller animals in comparison to the much larger and more robust Tarbosaurus.

Alioramus Reconstruction with scale (Art and Copyright belongs to Robinson Kunz; Teratophoneus on DeviantArt)

           Speaking of phylogeny, Alioramus has been placed under its own subfamily, Alioramini, which lies inside the family Tyrannosaurinae. Tyrannosaurinae consists of the later tyrannosaurs that shared the characteristics of a atrophied arms, large skulls, and slender legs. Alioramini’s only other member is the recently discovered Qianzhousaurus. Alioramus is related to the other, more well known, tyrannosaurs like; Albertosaurus, Daspletosaurus, Tarbosaurus, and Tyrannosaurus. The 2001 Alioramus finds found that, although the animal had a thin snout usually characteristic of more basal (primitive) forms, it was more related to the large robust forms seen living in close historical proximity to it; I.E. Tyrannosaurus.



            Mongolia, the region of which Alioramus called home, is home to a vast array of other animals that we know a lot about due to over 30 years of research and discovery in the region. Tarbosaurus, Deinocheirus, Gallimimus, Therizinosaurus, Homalocephale, and Nemegtosaurus all shared the ecosystem with Alioramus.



Works Cited:

"Alioramus." Wikipedia. Wikimedia Foundation, n.d. Web. 30 Dec. 2015. <https://en.wikipedia.org/wiki/Alioramus>.

Switek, Brian. "Alioramus Altai: A New, Multi-Horned Tyrant." Smithsonian. Smithsonian, 6 Oct. 2009. Web. 30 Dec. 2015. <http://www.smithsonianmag.com/science-nature/alioramus-altai-a-new-multi-horned-tyrant-54512057/?no-ist>.

Murray, Melissa. "Australian Museum." Alioramus Altai -. Australian Museum, 20 Nov. 2013. Web. 30 Dec. 2015. <http://australianmuseum.net.au/alioramus-altai>.

Hone, Dave. "Guest Post: A New Tyrannosaur - Alioramus Altai." Dave Hones Archosaur Musings. Word Press, 05 Oct. 2009. Web. 30 Dec. 2015. <https://archosaurmusings.wordpress.com/2009/10/06/guest-post-a-new-tyrannosaur-alioramus-altai/>.