Timurlengia

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Timurlengia
Temporal range:
Ma
↓
Restoration
Scientific classification Edit this classification
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

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.

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,

CAT-scans showed that Timurlengia had long inner ear canals, for hearing low-frequency sounds.[2]

The species was based on 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

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

semicircular canals.[1]

Phylogeny

Timurlengia was placed in the

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

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]

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

References

  1. ^
    PMID 26976562.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  2. ^ a b Greshko, Michael (March 14, 2016). "'Missing Link' in Tyrannosaur Family Tree Discovered". National Geographic News. Archived from the original on March 14, 2016. Retrieved 2016-03-15.
  3. doi:10.1016/j.cretres.2011.11.009
    .
  4. PMID 34527277
    .
  5. ^ a b c "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. S2CID 146115938
    .
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