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TARCHIA

a herbivorous ankylosaurid dinosaur from the Late Cretacous of Mongolia.
Pronunciation: TAHRK-ee-uh
Meaning: Brainy one
Author/s: Maryańska (1956)
Synonyms: Minotaurasaurus?
First Discovery: Ömnögovi, Mongolia
Chart Position: 209

Tarchia kielanae

On the outside, the skull of Tarchia is a heavyweight crash helmet; perhaps thirty inches from front to back in large adult specimens and roughly the same across its widest point, and thick with bulbous armour, while on the inside its braincase is twice the height of any of its ilk which presumably meant it was twice as clever (hence the name "brainy one"). While you don't have to be too clever to be the cleverest ankylosaur, Tarchia didn't have to worry about thinking... or think about worrying... because it was built like a Sherman tank, armour plated, and blessed with a tail club that would make Hercules proud. But sometimes, the pen is mightier than the club, and we can't remember a time when this plodding quadrupedal plant muncher wasn't being beaten senseless, in a literary sense.

Tarchia kielanae was coined in a 1977 monograph by Teresa Maryanska for a partial skull (ZPAL MgD I/111) from the Barun Goyot Formation at Khulsan, but it barely had time to settle into its shiny new berth on the armoured dinosaur branch of the dinosaurian family tree before it was the subject of a hostile takeover. In 1956, Evgeny Maleev had assigned a partial ankylosaurid skeleton (PIN 551/29) from Mongolia's Nemegt Formation to North America's Dyoplosaurus as a second species (Dyoplosaurus giganteus), but it became Euoplocephalus giganteus in 1971 when Walter Coombes sank the Dyoplosaurus type specimen (Dyoplosaurus acutosquameus) into Euoplocephalus. Later in 1977, Tatiana Tumanova assigned these remains to Maryanska's Tarchia as a second species (Tarchia gigantea), and a decade later referred a skull and partial skeleton (PIN 3142/250) from Hermiin Tsav to it, but by this point she was riddled with doubt and wandering if the two species of Tarchia were perhaps one and the same, despite a severe shortage of overlapping parts for comparison. Coombs and Maryanska combined the two Tarchia species in 1990 with Tarchia gigantea as type-specimen because it was described first, albeit as Dyoplosaurus giganteus, then Tumanova did the same a decade later, and despite both instances occuring in popular books as opposed to scientific papers, later authors followed suite.

We felt a sense of injustice when Tarchia Kielenae was unceremoniously ousted as name-bearer by Tarchia gigantea despite the fact that it had been renamed twice already, and all hope looked to be lost by the time Victoria Arbour arrived at the Zoological Institute of Paleobiology (ZPAL) in Warsaw to study ankylosaurids for her PhD in 2009, only to realise that its holotype—a skull—had been carelessly misplaced. Arbour perservered, however, and in 2014 announced that Tarchia gigantea—including several specimens she had described in great detail herself during the previous couple of years—was a nomen dubium as it possessed no diagnostic features and is indistinguishable from any other ankylosaur from the latest Cretaceous... apart from all known specimens of North America's Ankylosaurus, and specimen ZPAL MgD-I/113 which, funnily enough, it currently owns. Miraculously, the bad news turned to good when Tarchia kielenae was immediately revived as a valid genus based on nothing but black and white photos for reference, and was bolstered with a second, more complete skull which systematically struck the controvertial Minotaurasaurus from the roll call of dinosaurs. On the flipside, Arbour reassigned PIN 3142/250—a skull and as-yet undescribed partial skeleton from the Nemegt Formation at Hermiin Tsav that was responsible for Dyoplosaurus giganteus being moved to Tarchia in the first place, and on which most Tarchia research had been based—to Saichania chulsaensis, much to the chagrin of Tatiana Tumanova. The latter has already reinstated Minotaurasaurus after comparing its skull and referred specimen MAE 98 179 (that was not discussed by Arbour) from the "Xanadu" site in the Djadokhta Formation at Ukhaa Tolgod to the thought-lost Tarchia kielenae skull first hand, and reversed the referral of PIN 3142/250 to Saichania, instead renaming it Tarchia teresae. We fully expect to be editing this entry again real soon.

Tarchia is currently the youngest of the Asian branch of Ankylosauridae but is one of the biggest known from any time or place. If it manages to lay claim to specimens ZPAL MgD-I/43 and ZPAL MgD-I/113 that were previously assigned to Tarchia gigantea it will own the biggest club knob attached to the longest tail club handle too, and be the first Mongolian ankylosaurid to preserve evidence of keratinous scales on its armour plates, meaning even its armour was armoured.
(Kielan-Jaworowska's brainy one)Etymology
Tarchia is derived from the Mongolian "tarkhi" which means "brain", in reference to its big ol' braincase. The species epithet, kielanae, honors Prof. Zofia Kielan-Jaworowska in recognition of her work on Mongolian vertebrates.
Discovery
The first specimen of Tarchia kielanae was discovered in the Barun Goyot Formation at Khulsan, Mongolia. The holotype (ZPAL MgD-I/111) is a partial skull roof and braincase. Referred material includes a fragmentary skull and osteoderms (ZPAL MgD I/114) from the Barun Goyot Formation at Hermiin Tsav II, and Minotaurasaurus ramachandrani (INBR 21004 and MAE 98 179) may/may not belong here too, depending on which palaeontologist you support.
Tarchia gigantea ("Dyoplosaurus giganteus") was struck off as dubious by Arbour in 2014, but we might as well list the specimens that have been assigned to it, incase they're diagnostic again next week...
PIN 551/29—a series of caudal (tail) vertebrae, hand and finger bones, and some armour plates from Mongolia's Nemegt Formation—became the holotype of Dyoplosaurus giganteus, courtesy of Evgeny Maleev in 1956. It was renamed Tarchia gigantea by Tatiana Tumanova in 1977.
ZPAL MgD-I/43—a portion of tail with a tail-club from the Nemegt Formation at Altan Uul IV, Mongolia—was assigned to Dyoplosaurus giganteus by Maryanska in 1977. This specimen owns the the largest known ankylosaurid tail club knob, measuring some 62 cm across. It was referred to Tarchia teresae by Penalski and Tumanova in 2017.
ZPAL MgD-I/42—a portion of tail with a much smaller tail-club (about 21cm wide) and fragments of armour from the Nemegt Formation at Altan Uul IV, Mongolia—was also assigned to Dyoplosaurus giganteus by Maryanska in 1977.
ZPAL MgD-I/49—a right humerus from the Nemegt Formation at Altan Uul IV, Mongolia—was also assigned to Dyoplosaurus giganteus by Maryanska in 1977.
ZPAL MgD-I/113—a partial pelvis and club-knob-lacking tail, found in Mongolia's Nemegt Formation at Altan Uul III during the Polish-Mongolian Palaeontological Expedition of 1971—was assigned to Dyoplosaurus giganteus by Maryanska in 1977. It was "referred" to Tarchia gigantea by Arbour in 2013 based on the fact that it comes from the same formation as the holotype, even though it already made the journey to Tarchia gigantea when Tumanova renamed Dyoplosaurus giganteus in 1977. This specimen preserves unique in-situ triangular osteoderms (armour plates) along its tail and soft tissue scale impressions. With at least seventeen vertebrae that form part of it, ZPAL MgD I/113 has a longer tail club handle than Dyoplosaurus (approximately eleven) and Saichania (approximately twelve), and is, perhaps, only beaten in length by Pinacosaurus which has at least eighteen in specimen ZPAL MgD I/9.
PIN 3142/250—a skull and as-yet undescribed skeleton from the Nemegt Formation at Hermiin Tsav I—was assigned to Tarchia gigantea by Tumanova in 1987 and is the specimen that most palaeontologists studied when they studied Tarchia. Arbour and Currie moved it to Saichania chulsaensis in 2014 but, in 2016, Penalski and Tumanova renamed this specimen Tarchia teresae, in recognition of Teresa Maryanska and her work on Asian dinosaurs.
Estimations
Timeline:
Era: Mesozoic
Epoch: Late Cretaceous
Stage: Campanian-Maastrichtian
Age range: 75-68 mya
Stats:
Est. max. length: 8.5 meters
Est. max. hip height: 3 meters
Est. max. weight: 3 tons
Diet: Herbivore
References
• Maleev EA "Pantsyrnye dinosavry verchnego mela Mongolii (Semeustvo Ankylosauridae)—Armored dinosaurs from the Upper Cretaceous of Monglia (family Ankylosauridae)" Trudy Paleontologicheskogo Instituta Akademiy Nauk SSSR 62: 51-91. [translated by Welsh and Carpenter]
• Walter Preston Coombs Jr. (1971) "The Ankylosauria". PhD dissertation, Columbia University, New York.
• Maryanska T (1977) "Ankylosauridae (Dinosauria) from Mongolia".
• Tumanova TA (1977) "New data on the ankylosaur Tarchia gigantea". Paleontologicheskii Zhurnal (4): 92-100.
• Coombs WP Jr. (1978) "The families of the ornithischian dinosaur order Ankylosauria". Journal of Paleontology, Vol 21, Pages 143–170
• Tumanova TA (1987) "The Armored Dinosaurs of Mongolia". The Joint Soviet-Mongolian Paleontological Expedition Transaction vol. 32. [Translated by Ruth Griffith, edited by Carpenter and Tumanova]
• Tumanova TA (2000) "Armoured dinosaurs from the Cretaceous of Mongolia". In Benton et al. (eds.) "The Age of Dinosaurs in Russia and Mongolia". Pages 517-532.
• Alicea J and Loewen M (2013) "New Minotaurasaurus material from the Djodokta Formation establishes new taxonomic and stratigraphic criteria for the taxon". Society of Vertebrate Paleontology 73rd annual meeting, October-November 2013, abstracts of papers.
• Arbour VM, Lech-Hernes NL, Guldberg TE, et al. (2013) "An ankylosaurid dinosaur from Mongolia with in situ armour and keratinous scale impressions". Acta Palaeontologica Polonica 58 (1): 55–64.
• Victoria Megan Arbour (2014) "Systematics, evolution, and biogeography of the ankylosaurid dinosaurs". [University of Alberta PhD thesis]
• Arbour VM, Currie PJ & Badamgarav D (2014) "The ankylosaurid dinosaurs of the Upper Cretaceous Baruungoyot and Nemegt formations of Mongolia". Zoological Journ. of the Linnean Soc. 172(3): 631-652.
• Paul Penkalski and Tat'yana A. Tumanova (2016) "The cranial morphology and taxonomic status of Tarchia (Dinosauria: Ankylosauridae) from the Upper Cretaceous of Mongolia". Cretaceous Research, Volume 70, February 2017, Pages 117–127.
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To cite this page:
Atkinson, L. "TARCHIA :: from DinoChecker's dinosaur archive".
›. Web access: 25th Nov 2017.
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