Timurlengia

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Timurlengia
Temporal range: Late Cretaceous, 92–90  Ma
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Timurlengia.jpg
Restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Pantyrannosauria
Genus: Timurlengia
Brusatte et al., 2016
Type species
Timurlengia euotica
Brusatte et al., 2016

Timurlengia is an extinct genus of tyrannosauroid theropod dinosaur found in Uzbekistan, in the Bissekty Formation in the Kyzylkum Desert, hailing from the Turonian age of the early Late Cretaceous. The type species is Timurlengia euotica.

Contents

Discovery

From 1944 onwards, tyrannosauroid fossil material consisting of single bones has been described from the Bissekty Formation by Soviet or Russian researchers. [1] In 2004 a team discovered a braincase, which would have anchored the dinosaur's neck muscles and protected its brain and ear canals. The braincase was stored in a cardboard box in the Zoological Institute of the Russian Academy of Sciences, until tyrannosaur expert Steve Brusatte identified it as a distinctive new species in 2014. [2]

In 2016, Stephen Louis Brusatte, Alexander Averianov, Hans-Dieter Sues, Amy Muir, and Ian B. Butler named and described the type species Timurlengia euotica. The genus is named after Timurleng, founder of the Timurid Empire in Central Asia. The specific name euotica is Greek for “well-eared”, [1] because detailed CAT-scans showed that Timurlengia had long inner ear canals, for hearing low-frequency sounds. [2]

The species was based on the holotype, specimen ZIN PH 1146/16, consisting of the braincase. Other bones, not belonging to a single individual, and described in 2012, [3] were referred to the species. These included the specimens ZIN PH 854/16: the right half of a braincase; ZIN PH 676/16: a right maxilla; ZIN PH 2330/16: a left frontal bone; ZIN PH 2296/16: a left quadrate; ZIN PH 15/16: a piece of a right dentary; ZIN PH 1239/16: a right articular with angular; ZIN PH 671/16: a front neck vertebra; USNM 538131: a rear neck vertebra; USNM 538132: the neural arch of front back vertebra; CCMGE 432/12457: a middle back vertebra; ZIN PH 951/16: a front tail vertebra; ZIN PH 120/16: a middle tail vertebra; ZIN PH 120/16: a rear tail vertebra; ZINPH 619/16; and USNM 538167: a toe claw. These fossils were referred under the assumption that but a single tyrannosauroid taxon is present in the Bissekty Formation. [1]

Description

Size comparison Timurlengia Scale.svg
Size comparison

The holotype specimen belonging to a subadult was about 3–4 m (9.8–13.1 ft) long and weighed 170–270 kg (370–600 lb). [1] [4] ZIN PH 1239/16 represents a larger, adult individual. [1]

In 2016, several distinguishing traits were established, all pertaining to the holotype braincase. The supraoccipital bone, the central upper bone of the rear of the skull, has a diamond-shaped process pointing to below and not reaching the upper rim of the foramen magnum. The basioccipital has extremely short basal tubers, only attaining a third of the height of the occipital condyle. The oval window and the ear vestibule form a funnel-shaped recess penetrating deep into the ear zone and having a wide exit on the side wall of the braincase. The inner ear is large with robust semicircular canals. [1]

Phylogeny

Timurlengia was placed in the Tyrannosauroidea, in a basal position, as a possible sister species of Xiongguanlong . Together they may represent a clade of long-snouted forms that might have been the sister group of the Tyrannosauridae. [1]

The genus is important in showing how earlier small tyrannosauroids evolved into the large Tyrannosauridae like Tyrannosaurus , typical of the Late Cretaceous period of Asia and North America. The species is not believed to be a direct ancestor of Tyrannosaurus. [5] Timurlengia lived ninety million years ago, in the middle-late Turonian age of the early Late Cretaceous, right before the rise of the advanced tyrannosaurids. There had been a twenty million year "tyrannosaur gap" in the fossil records of the tyrannosauroid timeline, between the small "marginal hunters" and the "apex predators" of the tyrannosaurid group. The discovery of Timurlengia has filled that gap. [1] Timurlengia reveals that tyrannosaurs had yet to achieve huge size at this time but had already evolved key brain and sensory features of the gigantic latest Cretaceous species. These features were originally thought to be unique to big tyrannosaurs, as they evolved into large animals. [6] Tyrannosaurs apparently developed huge size rapidly during the late Cretaceous, and their success in the top predator role may have been enabled by their brain and keen senses which first evolved at a smaller body size. [7] Timurlengia's small size indicates that tyrannosaurs only evolved their large size in the last twenty million years of their evolution. [8] It is unknown what precisely triggered the size increase. [1]

The braincase of Timurlengia shows that tyrannosaurs likely developed their advanced head first, as hypothesised by Hans-Dieter Sues, one of the fossil's describers. Timurlengia’s skull, though much smaller than that of Tyrannosaurus, shows a sophisticated brain that would have led to keen eyesight, smell and hearing. At the time tyrannosaurs were developing acute senses and cognitive abilities, other large meat-eating dinosaurs such as the Carnosauria were disappearing from the environment or dying out, creating a vacant niche, allowing tyrannosaurs to become apex predators. [5] [9] The head of Timurlengia is far less pneumatised than that of the larger tyrannosaurids; the increased airspaces with the later forms might have been an adaptation to lighten the skull or to keep a good hearing ability despite the larger size. [1]

Classification

Below is the phylogenetic analysis on the placement of Timurlengia. [10]

Tyrannosauroidea

Proceratosauridae

Stokesosaurus

Juratyrant

Eotyrannus

Suskityrannus

Timurlengia

Xiongguanlong

Dryptosaurus

Appalachiosaurus

Bistahieversor

Tyrannosauridae

Paleobiology

Timurlengia was likely a pursuit hunter with blade-like teeth for slicing through meat, based on its skeletal remains. [5] The robustness of the semicircular inner ear canals might be related to a greater agility. Timurlengia has a long cochlear duct, with the same height as the labyrinth, an adaptation to hearing low-frequency sounds. This might be an indication that the animal used low calls to communicate within the species. [1]

See also

Related Research Articles

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<span class="mw-page-title-main">Tyrannosauridae</span> Family of dinosaurs

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<i>Dilong paradoxus</i> Extinct species of dinosaur

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<i>Alioramus</i> Tyrannosaurid theropod dinosaur genus from the Late Cretaceous period

Alioramus is a genus of tyrannosaurid theropod dinosaurs from the Late Cretaceous period of Asia. It currently contains two species. The type species, A. remotus is known from a partial skull and three foot bones recovered from the Mongolian Nemegt Formation, which was deposited in a humid floodplain about 70 million years ago. These remains were named and described by Soviet paleontologist Sergei Kurzanov in 1976. A second species, A. altai, known from a much more complete skeleton also from the Nemegt Formation, was named and described by Stephen L. Brusatte and colleagues in 2009. Its relationships to other tyrannosaurid genera were at first unclear, with some evidence supporting a hypothesis that Alioramus was closely related to the contemporary species Tarbosaurus bataar. However, the discovery of Qianzhousaurus indicates that it belongs to a distinct branch of tyrannosaurs, namely the tribe Alioramini.

<span class="mw-page-title-main">Tyrannosauroidea</span> Extinct superfamily of dinosaurs

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Bissektipelta is a genus of ankylosaurine thyreophoran dinosaurs that lived in Asia during the Late Cretaceous in what is now the Bissekty Formation of Uzbekistan. Bissektipelta is a monospecific genus, containing only the type species B. archibaldi.

<i>Xiongguanlong</i> Extinct genus of dinosaurs

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The Bissekty Formation is a geologic formation and Lagerstätte which crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period. Laid down in the mid to late Turonian, it is dated to about 92 to 90 Ma.

<i>Shaochilong</i> Extinct genus of dinosaurs

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<i>Raptorex</i> Extinct genus of dinosaurs

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<i>Sinotyrannus</i> Extinct genus of dinosaurs

Sinotyrannus is a genus of large basal tyrannosauroid dinosaur, known from a single incomplete fossil specimen including a partial skull, from the Early Cretaceous Jiufotang Formation of Liaoning, China. Specifically, it is a member of the Proceratosauridae, a family that originated in the Jurassic whose members are known from Europe and Asia. Though it is not much younger than primitive tyrannosauroids such as Dilong, it is similar in size to later forms such as Tyrannosaurus. It was much larger than contemporary tyrannosauroids, reaching a total estimated length of 9–10 m (30–33 ft), and was the largest known theropod from the Jiufotang Formation. The type species is S. kazuoensis, described by Ji et al., in 2009.

<i>Bistahieversor</i> Extinct genus of dinosaurs

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<i>Lythronax</i> Genus of tyrannosaurid dinosaur from the Late Cretaceous period

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<i>Suskityrannus</i> Extinct genus of dinosaurs

Suskityrannus is a genus of small tyrannosauroid theropod from the Late Cretaceous in southern Laramidia. It contains a single species, Suskityrannus hazelae, believed to have lived roughly 92 million years ago. The type specimen was found in the Turonian-age Moreno Hill Formation of the Zuni Basin in western New Mexico.

<span class="mw-page-title-main">Timeline of tyrannosaur research</span>

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<span class="mw-page-title-main">Eutyrannosauria</span> Clade of theropods

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<i>Dzharatitanis</i> Extinct genus of dinosaurs

Dzharatitanis is a genus of sauropod from the Bissekty Formation in Uzbekistan, dating to the Turonian age of the Late Cretaceous. The genus contains a single species, Dzharatitanis kingi, named after geologist Christopher King, who contributed to the Cretaceous geology of Asia. It is currently one of two known sauropods from the Bissekty Formation, alongside an indeterminate titanosaur. In its original publication it was considered to be a member of Rebbachisauridae, but later papers considered it to be a titanosaur.

<i>Ulughbegsaurus</i> Genus of carcharodontosaurid (fossil)

Ulughbegsaurus is a dubious genus of theropod dinosaur from the Late Cretaceous aged Bissekty Formation, Uzbekistan. The type species is Ulughbegsaurus uzbekistanensis.

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References

  1. 1 2 3 4 5 6 7 8 9 10 11 Stephen L. Brusatte, Alexander Averianov, Hans-Dieter Sues, Amy Muir and Ian B. Butler (2016). "New tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies evolution of giant body sizes and advanced senses in tyrant dinosaurs". Proceedings of the National Academy of Sciences of the United States of America. 113 (13): 3447–3452. Bibcode:2016PNAS..113.3447B. doi: 10.1073/pnas.1600140113 . PMC   4822578 . PMID   26976562.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. 1 2 Greshko, Michael (March 14, 2016). "'Missing Link' in Tyrannosaur Family Tree Discovered". National Geographic News. Retrieved 2016-03-15.
  3. Averianov, A.; Sues, H-D. (2012). "Skeletal remains of Tyrannosauroidea (Dinosauria: Theropoda) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan". Cretaceous Research. 34: 284–297. Bibcode:2012CrRes..34..284A. doi:10.1016/j.cretres.2011.11.009.
  4. Tanaka K, Anvarov OU, Zelenitsky DK, Ahmedshaev AS, Kobayashi Y (2021). "A new carcharodontosaurian theropod dinosaur occupies apex predator niche in the early Late Cretaceous of Uzbekistan". Royal Society Open Science. 8 (9): Article ID 210923. Bibcode:2021RSOS....810923T. doi: 10.1098/rsos.210923 . PMC   8424376 . PMID   34527277.
  5. 1 2 3 "New horse-sized tyrannosaur with big brain reveals how "T. rex" became top predator". Smithsonian Science News -. 14 March 2016. Retrieved 2016-03-15.
  6. Brusatte, Stephen. "New Tyrannosaur Species Reveals How the King of the Dinosaurs Won Its Crown". Scientific American. Retrieved 2016-03-15.
  7. "Newly Discovered Dinosaur Helps Explain Rise Of Tyrannosaurs". NPR.org. Retrieved 2016-03-15.
  8. "Newly discovered dinosaur reveals how T. rex became king of the Cretaceous". ScienceDaily.
  9. Matt Atherton (14 March 2016). "Timurlengia euotica: Distant relative of T-rex shows how dinosaur became giant". International Business Times UK. Retrieved 27 March 2016.
  10. Wolfe, D.G.; McDonald, A.T.; Kirkland, J.I.; Turner, A.H.; Smith, N.D.; Brusatte, S.L.; Loewen, M.A.; Denton, R.K.; Nesbitt, S.J. (6 May 2019). "A mid-Cretaceous tyrannosauroid and the origin of North American end-Cretaceous dinosaur assemblages" (PDF). Nature Ecology & Evolution. 3 (6): 892–899. doi:10.1038/s41559-019-0888-0. hdl: 20.500.11820/a6709b34-e3ab-416e-a866-03ba1162b23d . PMID   31061476. S2CID   146115938.