Bistahieversor

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Bistahieversor
Temporal range: Late Cretaceous, 75.5–74.5  Ma
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Bistahieversor.jpg
Skull and vertebra at the New Mexico Museum of Natural History and Science
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Eutyrannosauria
Genus: Bistahieversor
Carr & Williamson, 2010
Species:
B. sealeyi
Binomial name
Bistahieversor sealeyi
Carr & Williamson, 2010

Bistahieversor (meaning "Bistahi destroyer"), also known as the "Bisti Beast", is a genus of basal eutyrannosaurian theropod dinosaur. The genus contains only a single known species, B. sealeyi, described in 2010, from the Late Cretaceous [1] of New Mexico. The holotype and a juvenile were found in the Hunter Wash Member of the Kirtland Formation, while other specimens came from the underlying Fossil Forest member of the Fruitland Formation. This dates Bistahieversor approximately 75.5 to 74.5 million years ago during the Campanian age, found in sediments spanning a million years.

Contents

Discovery and naming

Holotype skull during preparation Bistahieversor-skull.jpg
Holotype skull during preparation

The first remains now attributed to Bistahieversor, a partial skull and skeleton, were described in 1990 as a specimen of Aublysodon . [2] Additional remains, consisting of the incomplete skull and skeleton of a juvenile, were described in 1992. [3] Another complete skull and partial skeleton were found in the Bisti/De-Na-Zin Wilderness Area of New Mexico in 1998, [4] known colloquially as the "Bisti Beast". [5]

In a 2000 paper, Thomas Carr and Thomas Williamson re-examined these four specimens and suggested that they did not belong to Aublysodon, but rather to one or more new species of Daspletosaurus . [6] However, it was not until 2010 that Carr and Williamson published a thorough re-description of the specimens and found that they belonged to a new genus and species of more generalized tyrannosauroid. They named it Bistahieversor sealeyi. [1] The name Bistahieversor comes from the Navajo Bistahí, or "place of the adobe formations" in reference to the Bisti/De-Na-Zin Wilderness Area where it was found. Eversor, the latter part of the name, means "destroyer." [1]

Description

Size comparison with a juvenile Bistahieversor SIZE.png
Size comparison with a juvenile

Material from both juveniles and adults has been found in the Kirtland and Fruitland formations of New Mexico. Adult Bistahieversor are estimated to have been around 9 meters (30 ft) long and weigh at least a ton. The snout is deep, indicating that the feature is not unique to more derived tyrannosaurs, such as Tyrannosaurus . Geographical barriers, such as the newly forming Rocky Mountains, may have isolated the more southerly Bistahieversor from more derived northern tyrannosaurs. [7] In 2010, Gregory S. Paul estimated a length of 8 meters (26 ft) and a weight of 2.5 metric tons (2.75 short tons). [8] In 2016, Molina-Pérez and Larramendi gave a length of 9 meters (29.5 ft) and a weight of 3.3 metric tons (3.6 short tons). [9]

Life restoration Bihastieversor NT.jpg
Life restoration

Bistahieversor differs from other tyrannosaurs in the possession of 64 teeth, an extra opening above the eye, and a keel along the lower jaw, among many other unique traits. The opening above the eye is thought to have accommodated an air sac that would have lightened the skull's weight. Bistahieversor also had a complex joint at its "forehead" that would have stabilized the skull to prevent movement at the joint. [10]

Classification

Wall-mounted juvenile Bistahieversor mount.jpg
Wall-mounted juvenile
Holotype skull exhibited at the Smithsonian Museum Bistahieversor sealeyi.jpg
Holotype skull exhibited at the Smithsonian Museum

Bistahieversor is a genus of derived tyrannosaur currently classified in the subfamily Tyrannosaurinae. It is more derived than Teratophoneus , but less derived than Lythronax . [11] It forms the sister taxon of a group that includes Lythronax, Nanuqsaurus , Tyrannosaurus , Tarbosaurus , and Zhuchengtyrannus . [12]

Below is a cladogram illustrating the relationships of all tyrannosaurid genera: [12]

Tyrannosauridae
Albertosaurinae

Albertosaurus

Gorgosaurus

Tyrannosaurinae

Daspletosaurus torosus

Daspletosaurus horneri

Teratophoneus

Bistahieversor

Lythronax

Nanuqsaurus

Tarbosaurus

Zhuchengtyrannus

Tyrannosaurus

The cladogram below is based on a phylogenetic analysis conducted by Voris et al. in 2020. Here, Bistahieversor was recovered as a basal member of Eutyrannosauria alongside Dryptosaurus and Appalachiosaurus instead of as a tyrannosaurine: [13]

Eutyrannosauria

Dryptosaurus aquilunguis

Appalachiosaurus montgomeriensis

Bistahieversor sealeyi

Tyrannosauridae  
Albertosaurinae

Gorgosaurus libratus

Albertosaurus sarcophagus

Tyrannosaurinae
Alioramini

Qianzhousaurus sinensis

Alioramus remotus

Alioramus altai

Teratophoneus curriei

Dynamoterror dynastes

Lythronax argestes

Nanuqsaurus hoglundi

Daspletosaurini

Thanatotheristes degrootorum

Daspletosaurus torosus

Daspletosaurus horneri

Zhuchengtyrannus magnus

Tarbosaurus bataar

Tyrannosaurus rex

Paleobiology

Restoration of Bistahieversor hunting Pentaceratops Bistahieversor hunting Pentaceratops.jpg
Restoration of Bistahieversor hunting Pentaceratops

A 2020 study of the endocranial morphology of Bistahieversor shed some light on its hunting behaviors. Its large olfactory bulbs indicate a very heightened sense of smell, while the elongated semi-circular canals implied increased agility and sophisticated gaze stabilization while the head was moving. Bistahieversor also possessed binocular vision, allowing it to see much better than more primitive predatory dinosaurs. The study noted that, while Bistahieversor had small optic lobes, this was not a strong indicator of whether or not this dinosaur possessed poor vision. [14]

See also

Related Research Articles

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

Tyrannosauridae is a family of coelurosaurian theropod dinosaurs that comprises two subfamilies containing up to thirteen genera, including the eponymous Tyrannosaurus. The exact number of genera is controversial, with some experts recognizing as few as three. All of these animals lived near the end of the Cretaceous Period and their fossils have been found only in North America and Asia.

<i>Tarbosaurus</i> Tyrannosaurid dinosaur genus from Late Cretaceous of Mongolia

Tarbosaurus is a genus of tyrannosaurine theropod dinosaur that lived in Asia about 70 million years ago, during the Maastrichtian age at the end of the Late Cretaceous period, considered to contain a single known species: Tarbosaurus bataar. Fossils have been recovered from the Nemegt Formation of Mongolia, with more fragmentary remains found further afield in the Subashi Formation of China.

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

Daspletosaurus is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 77 and 75 million years ago, during the Late Cretaceous Period. The genus Daspletosaurus contains three species. Fossils of the earlier type species, D. torosus, have been found in Alberta, and fossils of a later second species, D. wilsoni, and third species, D. horneri, have been found only in Montana. A possible fourth species, also from Alberta, awaits formal identification. The taxon Thanatotheristes has been suggested to represent a species of Daspletosaurus, D. degrootorum, but this has not been widely supported. Daspletosaurus is closely related to the much larger and more recent tyrannosaurid Tyrannosaurus rex. Like most tyrannosaurids, Daspletosaurus was a multi-tonne bipedal predator equipped with dozens of large, sharp teeth. Daspletosaurus had the small forelimbs typical of tyrannosaurids, although they were proportionately longer than in other genera.

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

Dilong is a genus of basal tyrannosauroid dinosaur. The only species in this genus is Dilong paradoxus. It is from the Lower Cretaceous Yixian Formation near Lujiatun, Beipiao, in the western Liaoning province of China. It lived about 126 million years ago. This theropod discovery was significant as it was one of the first tyrannosauroids with fossil evidence of simple feathers.

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

Aublysodon is a genus of carnivorous dinosaurs known only from the Judith River Formation in Montana, which has been dated to the late Campanian age of the late Cretaceous period. The only currently recognized species, Aublysodon mirandus, was named by paleontologist Joseph Leidy in 1868. It is sometimes considered dubious now, because the type specimen consists only of an isolated premaxillary (front) tooth. Although this specimen is now lost, similar teeth have been found in many US states, western Canada, and Asia. These teeth almost certainly belong to juvenile tyrannosaurine tyrannosaurids, but most have not been identified to species level. However, it is likely that the type tooth belongs to one of the species in the genus Daspletosaurus, which was present in contemporary formations, and which matches specific details of the original tooth. The synapomorphies alleged to distinguish the Aublysodontinae, especially lack of serrations on premaxillary teeth could have been caused by tooth wear in life, postmortem abrasion, or digestion. Most other "aublysodontine"-type teeth may be from ontogenetic stages or sexual morphs of other tyrannosaurids.

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

Appalachiosaurus is a genus of basal eutyrannosaurian theropod dinosaur from the middle Campanian age of the Late Cretaceous period of what is now eastern North America. Like all theropods, it was a bipedal predator. Only a juvenile skeleton has been found, representing an animal approximately 6.5 metres (21 ft) long and weighing 623 kilograms (1,373 lb), which indicates an adult would have been significantly larger. It is the most completely known theropod from eastern North America.

<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

Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period. By the end of the Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic Tyrannosaurus. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe and Asia, with fragmentary remains possibly attributable to tyrannosaurs also known from South America and Australia.

<span class="mw-page-title-main">Tyrannosaurinae</span> Extinct subfamily of dinosaurs

Tyrannosaurinae is one of the two extinct subfamilies of Tyrannosauridae, a family of coelurosaurian theropods that consists of at least three tribes and several genera. All fossils of these genera have been found in the Late Cretaceous deposits of western North America and east Asia. Compared to the related subfamily Albertosaurinae, tyrannosaurines overall are more robust and larger though the alioramins were gracile by comparison. This subfamily also includes the oldest known tyrannosaurid genus Lythronax as well as the youngest and most famous member of the group, Tyrannosaurus rex. There were at least 30 different species of tyrannosaurines.

<span class="mw-page-title-main">Albertosaurinae</span> Extinct subfamily of dinosaurs

Albertosaurines, or dinosaurs of the subfamily Albertosaurinae, lived in the Late Cretaceous of United States and Canada. The subfamily was first used by Philip J. Currie, Jørn H. Hurum, and Karol Sabath as a group of tyrannosaurid dinosaurs. It was originally defined as "(Albertosaurus + Gorgosaurus)", including only the two genera. The group is the sister clade to Tyrannosaurinae. In 2007, it was found that the group also contained Maleevosaurus, often synonymized with Tarbosaurus. However, this classification has not been accepted and Maleevosaurus is still considered a juvenile Tarbosaurus or Tyrannosaurus.

Thomas D. Carr is a vertebrate paleontologist who received his Ph.D. from the University of Toronto in 2005. He is now a member of the biology faculty at Carthage College in Kenosha, Wisconsin. Much of his work centers on tyrannosauroid dinosaurs. Carr published the first quantitative analysis of tyrannosaurid ontogeny in 1999, establishing that several previously recognized genera and species of tyrannosaurids were in fact juveniles of other recognized taxa. Carr shared the Lanzendorf Prize for scientific illustration at the 2000 Society of Vertebrate Paleontology conference for the artwork in this article. In 2005, he and two colleagues described and named Appalachiosaurus, a late-surviving basal tyrannosauroid found in Alabama. He is also scientific advisor to the Dinosaur Discovery Museum in Kenosha, Wisconsin.

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

Xiongguanlong is an extinct genus of tyrannosauroid theropod from the Early Cretaceous period of what is now China. The type and only species is X. baimoensis. The generic name comes from Jiayuguan City and the Mandarin word "long" which means dragon. The specific epithet, "baimoensis" is a latinization of the Mandarin word for "white ghost" in reference to one of the geological features of the type locality.

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

Raptorex is a genus of tyrannosaurid dinosaur. Its fossil remains consist of a single juvenile specimen probably uncovered in Mongolia, or possibly northeastern China. The type species is R. kriegsteini, described in 2009 by Sereno and colleagues. The genus name is derived from Latin raptor, "robber", and rex, "king". The specific name honours Roman Kriegstein, a survivor of the Holocaust, whose son Henry Kriegstein donated the specimen to the University of Chicago for scientific study.

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

Teratophoneus is a genus of tyrannosaurine theropod dinosaur that lived during the late Campanian age of the Late Cretaceous period, in what is now Utah. It contains a single known species, T. curriei. It is known from an incomplete skull and postcranial skeleton recovered from the Kaiparowits Formation and was specifically named T. curriei in honor of famed paleontologist Philip J. Currie.

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

Zhuchengtyrannus is a genus of tyrannosaurid theropod dinosaur known from the Campanian stage of the Late Cretaceous of Shandong Province, China. It belongs to the subfamily Tyrannosaurinae, and contains a single species, Zhuchengtyrannus magnus.

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

Lythronax is a genus of tyrannosaurid dinosaur that lived in North America around 81.9-81.5 million years ago during the Late Cretaceous period. The only known specimen was discovered in Utah in the Wahweap Formation of the Grand Staircase–Escalante National Monument in 2009, and it consists of a partial skull and skeleton. In 2013, it became the basis of the new genus and species Lythronax argestes; the generic name Lythronax means "gore king", and the specific name argestes originates from the Greek poet Homer's name for the wind from the southwest, in reference to the specimen's geographic provenance in North America.

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

This timeline of tyrannosaur research is a chronological listing of events in the history of paleontology focused on the tyrannosaurs, a group of predatory theropod dinosaurs that began as small, long-armed bird-like creatures with elaborate cranial ornamentation but achieved apex predator status during the Late Cretaceous as their arms shrank and body size expanded. Although formally trained scientists did not begin to study tyrannosaur fossils until the mid-19th century, these remains may have been discovered by Native Americans and interpreted through a mythological lens. The Montana Crow tradition about thunder birds with two claws on their feet may have been inspired by isolated tyrannosaurid forelimbs found locally. Other legends possibly inspired by tyrannosaur remains include Cheyenne stories about a mythical creature called the Ahke, and Delaware stories about smoking the bones of ancient monsters to have wishes granted.

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

Eutyrannosauria is a clade of tyrannosauroid theropods whose distribution has been found in what is now Asia and North America. The clade consists of an evolutionary grade of tyrannosaurs such as Appalachiosaurus, Dryptosaurus, and Bistahieversor which led up to the family Tyrannosauridae. The group was named in 2018 by Delcourt and Grillo in their paper about possible southern hemisphere tyrannosauroids and the phylogeography of tyrannosaurs.

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

Dynamoterror is a monospecific genus of tyrannosaurid dinosaur from New Mexico that lived during the Late Cretaceous in what is now the upper Allison Member of the Menefee Formation. The type and only species, Dynamoterror dynastes, is known from a subadult or adult individual about 9 metres long with an incomplete associated skeleton. It was named in 2018 by Andrew T. McDonald, Douglas G. Wolfe and Alton C. Dooley, Jr. Dynamoterror was closely related to Teratophoneus and Lythronax.

<i>Thanatotheristes</i> Daspletosaurin tyrannosaurid of the mid-Campanian

Thanatotheristes is a genus of tyrannosaurid dinosaur from the Late Cretaceous of Laramidia, approximately 80.1-79.5 Ma. Thanatotheristes contains only one species, T. degrootorum. Fossils of this taxon are found in the Foremost Formation of Alberta, Canada, coexisting with medium-sized ceratopsids like Xenoceratops foremostensis and small pachycephalosaurids like Colepiocephale lambei.

References

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  2. Lehman, Thomas M.; Carpenter, Kenneth (November 1990). "A partial skeleton of the tyrannosaurid dinosaur Aublysodon from the Upper Cretaceous of New Mexico". Journal of Paleontology . 64 (6): 1026–1032. doi:10.1017/S0022336000019843. JSTOR   1305741. S2CID   132662000.
  3. Archer, Brad; Babiarz, John P. (July 1992). "Another tyrannosaurid dinosaur from the Cretaceous of northwest New Mexico". Journal of Paleontology . 66 (4): 690–691. doi:10.1017/S0022336000024598. S2CID   130535722.
  4. "New Species of Tyrannosaur Discovered in Southwestern U.S." Newswise. January 28, 2010. Retrieved February 1, 2010.
  5. "ABQJOURNAL NEWS/STATE: N.M. Tyrannosaur Is Officially Dubbed Bistahieversor sealeyi". www.abqjournal.com. Retrieved January 27, 2017.
  6. Carr, Thomas D.; Williamson, Thomas E. (2000). "A review of Tyrannosauridae (Dinosauria: Coelurosauria) from New Mexico". Bulletin. New Mexico Museum of Natural History and Science. 17: 113–145.
  7. Rettner, Rachael (January 28, 2010). "New Tyrannosaur Species Discovered". LiveScience. Retrieved February 1, 2010.
  8. Paul, Gregory S. (2010). The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 103.
  9. Molina-Pérez & Larramendi (2016). Récords y curiosidades de los dinosaurios Terópodos y otros dinosauromorfos. Barcelona, Spain: Larousse. p. 265.
  10. Viegas, J. (January 28, 2010). "New Tyrannosaur Had More Teeth Than T. rex". Discovery News. Retrieved February 1, 2010.
  11. Loewen, Mark A.; Irmis, Randall B.; Sertich, Joseph J. W.; Currie, Philip 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. Bibcode:2013PLoSO...879420L. doi: 10.1371/journal.pone.0079420 . PMC   3819173 . PMID   24223179.
  12. 1 2 Fiorillo, Anthony R.; Tykoski, Ronald S. (2014). Dodson, Peter (ed.). "A Diminutive New Tyrannosaur from the Top of the World". PLoS ONE . 9 (3): e91287. Bibcode:2014PLoSO...991287F. doi: 10.1371/journal.pone.0091287 . PMC   3951350 . PMID   24621577.
  13. Voris, Jared T.; Therrien, Francois; Zelenitzky, Darla K.; Brown, Caleb M. (2020). "A new tyrannosaurine (Theropoda:Tyrannosauridae) from the Campanian Foremost Formation of Alberta, Canada, provides insight into the evolution and biogeography of tyrannosaurids". Cretaceous Research . 110: 104388. doi:10.1016/j.cretres.2020.104388. S2CID   213838772.
  14. McKeown, Matthew; Brusatte, Stephen L.; Williamson, Thomas E.; Schwab, Julia A.; Carr, Thomas D.; Butler, Ian B.; Muir, Amy; Schroeder, Katlin; Espy, Michelle A.; Hunter, James F.; Losko, Adrian S. (2020). "Neurosensory and Sinus Evolution as Tyrannosauroid Dinosaurs Developed Giant Size: Insight from the Endocranial Anatomy of Bistahieversor sealeyi" (PDF). The Anatomical Record. 303 (4): 1043–1059. doi:10.1002/ar.24374. hdl: 20.500.11820/8c657729-91df-4f7c-bca5-b9c469781768 . ISSN   1932-8494. PMID   31967416. S2CID   210871038.