Buitreraptor

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Buitreraptor
Temporal range: Late Cretaceous,
~98–97  Ma
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BuitreraptorROM.JPG
Mounted skeleton, Royal Ontario Museum, Toronto, Canada
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Dromaeosauridae
Subfamily: Unenlagiinae
Genus: Buitreraptor
Makovicky et al. 2005
Type species
Buitreraptor gonzalezorum
Makovicky et al. 2005

Buitreraptor (meaning "La Buitrera seizer") is a genus of dromaeosaurid dinosaurs that lived during the Late Cretaceous of Argentina at the Candeleros Formation. Buitreraptor was described in 2005 and the type species is Buitreraptor gonzalezorum. It was rooster-sized and had a very elongated head with many small teeth.

Contents

History of discovery

Skeletal composite of specimens MPCA 245 and MPCA 238 Buitreraptor gonzalezorum.jpg
Skeletal composite of specimens MPCA 245 and MPCA 238

Four specimens of Buitreraptor were found in 2004 in sandstone in Patagonia, Argentina during an excavation led by Sebastián Apesteguia, researcher of CONICET at the Fundacion Felix de Azara - Maimonides University, and Peter Makovicky, curator of dinosaurs at the Field Museum in Chicago. Buitreraptor is from the early Late Cretaceous Candeleros Formation, dating to the Cenomanian-Turonian ages approximately 98 to 97 million years ago, when South America was an isolated continent like Australia today. It was uncovered in a famous fossil site named La Buitrera, the "vulture roost". Although dinosaurs are rare in this site, another nearby site had earlier yielded the giant Giganotosaurus , one of the largest known carnivorous dinosaurs. [1]

Buitreraptor gonzalezorum is the only known species of the genus Buitreraptor. It was named by Peter Makovicky, Sebastián Apesteguía and Federico Agnolín. The genus name means "vulture raider", from the Spanish word buitre meaning vulture, in reference to La Buitrera, and Latin raptor, "seizer". The specific name honours the González brothers, Fábian and Jorge, who realised much of the actual excavation and preparation of the fossils. [1] The holotype specimen, MPCA 245, consists of a partial skeleton with skull of an adult individual. The paratype is MPCA 238, a sacrum with a right pelvis and right hindlimb. [1] The skull of the holotype was described in detail in 2017, [2] while 2018 saw a slew of new papers on the anatomy of the genus. These include descriptions of new specimens, [3] a study on the tail anatomy of the genus, [4] and a general overview of the postcrania of multiple specimens. [5]

Description

Size compared to a human Buitreraptor gonzalezorum size chart.png
Size compared to a human

Buitreraptor was a rather small dinosaur. In 2010, Gregory S. Paul estimated the length at 1.5 metres, the weight at three kilograms. [6] Buitreraptor has some different physical features than typical northern dromaeosaurs, such as Velociraptor . Buitreraptor has a slender, flat, extremely elongated snout with many small teeth that lack meat-tearing serrations or cutting edges and are grooved, strongly recurved and flattened. [7] [8] From this, the scientists who initially described it concluded that this dinosaur was not a hunter of relatively large animals like some other dromaeosaurs, but rather a hunter of small animals such as lizards and mammals. The forelimbs of Buitreraptor were long and ended in very long and thin three-fingered hands. All known parts of the hand of Buitreraptor are proportionally longer than in the dromaeosaurids Deinonychus and Velociraptor , except for the ungual bones which are proportionally smaller in Buitreraptor. [3]

The body as a whole was also elongated, with a shallow ribcage. The enlarged sickle claw at the second toe of the foot formed a blade that was long although less large than in dromaeosaurids such as Velociraptor and Deinonychus. [3] No fossil discoveries have been made of any feathers of Buitreraptor. However, there are relatives like Microraptor and Sinornithosaurus , of which fossils with preserved feathers are known. Since its close relatives had feathers, it is likely that Buitreraptor also was feathered. According to Apesteguia, this is comparable to reconstructing an extinct monkey with fur because all modern monkeys have fur. [9]

Classification

Reconstructed skeleton of the holotype MPCA 245 at the Carlos Ameghino Provincial Museum Reconstruccion Buitreraptor gonzalezorum.jpg
Reconstructed skeleton of the holotype MPCA 245 at the Carlos Ameghino Provincial Museum

Buitreraptor shows a mosaic of dromaeosaurid, troodontid and avialan traits. It was in 2005 assigned to the Dromaeosauridae. A cladistic analysis by the describers showed it was part of the dromaeosaurid Unenlagiinae. [1] The discovery of Buitreraptor has also been the subject of discussion among scientists as to the question whether flight could have evolved independently in birds and dromaeosaurids or was derived from some flying common ancestor. Some scientists propose that Rahonavis , a relative to Buitreraptor, could fly. However, evidence for flight has not been unequivocally found in other dromaeosaurids, which has led some scientists to propose that dromaeosaurids evolved flight independently of birds if Rahonavis could indeed fly. [10]

The following cladogram is based on the phylogenetic analysis conducted by Hartman and colleagues in 2019, showing the relationships of Buitreraptor among the other genera assigned to the family "Unenlagiidae": [11]

Unenlagiidae

Evolution

Life restoration Buitreraptor NT.jpg
Life restoration

Other than Buitreraptor, the only other known dromaeosaurs from the southern continents are Neuquenraptor , Austroraptor , and Unenlagia from South America (discovered earlier in 2005), Rahonavis (once thought to be a true avian bird) from Madagascar, and unidentified dromaeosaur-like teeth from Australia. This discovery in the Southern Hemisphere helped scientists to clarify that the dromaeosaur family was more widely dispersed around the world than previously thought. Evidence indicates that dromaeosaurs first appeared during the Jurassic Period, when all the continents were much closer together than they are today. With the discovery of Buitreraptor, the scientists proposed that dromaeosaurids originated somewhere around 180 million years ago, before Pangaea broke up. [1] [12] However, other paleontologists have in later studies placed the time of origin for Dromaeosauridae to about 160 million years ago. [13]

The scientists see it as an alternative possibility that dromaeosaurids originated on the ancient continent Laurasia in the north and during the Cretaceous Period migrated to southern Gondwana, since the species known from the Southern Hemisphere bear distinctive characteristics not shared by their northern relatives. La Buitrera also yielded remains of terrestrial crocodiles, pterosaurs, the largest known rhynchocephalians, limbed snakes, iguanian lizards, chelid turtles, mammals, and dipnoan fishes [1]

Paleobiology

Unenlagiines had better capacities for running and pursuit predation than other dromaeosaurids such as Laurasian dromaeosaurids (Eudromaeosauria), which were more stocky and had shorter legs and had an active predatory lifestyle. Unenlagiines were highly cursorial animals because they were more gracile and had modified metatarsals that are relatively thin and lengthened. [14] Based on these adaptations, it is likely that unenlagiines preyed on small, fast animals, although the exact animals are unknown. [8] [15] [16] Buitreraptor features particular traits that can be attributed to specific hunting methods. Models for Buitreraptor propose that it hunted by traveling large distances in pursuit of prey, which may explain the long-legged trait shared by various genera of Unenlagiidae. Buitreraptor is characterized by its long forelimbs and hands; it likely relied on them to restrain prey and the curved claw of the second pedal digit would have injured or killed the victim. Buitreraptor probably swallowed its prey whole due to its lack of serrated teeth with flesh-tearing capabilities; the teeth functioned to simply hold prey. [17]

See also

Related Research Articles

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

Dromaeosauridae is a family of feathered coelurosaurian theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek δρομαῖος (dromaîos), meaning 'running at full speed', 'swift', and σαῦρος (saûros), meaning 'lizard'. In informal usage, they are often called raptors, a term popularized by the film Jurassic Park; several genera include the term "raptor" directly in their name, and popular culture has come to emphasize their bird-like appearance and speculated bird-like behavior.

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

Sinornithosaurus is a genus of feathered dromaeosaurid dinosaur from the early Cretaceous Period of the Yixian Formation in what is now China. It was the fifth non–avian feathered dinosaur genus discovered by 1999. The original specimen was collected from the Sihetun locality of western Liaoning. It was found in the Jianshangou beds of the Yixian Formation, dated to 124.5 million years ago. Additional specimens have been found in the younger Dawangzhangzi bed, dating to around 122 million years ago.

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

Neuquenraptor is a genus of dromaeosaurid theropod dinosaurs that lived in South America during the Late Cretaceous in what is now the Portezuelo Formation of Argentina. It is one of the first dromaeosaurids found in the Southern Hemisphere.

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

Rahonavis is a genus of bird-like theropod from the Late Cretaceous of what is now northwestern Madagascar. It is known from a partial skeleton found by Catherine Forster and colleagues in Maevarano Formation rocks at a quarry near Berivotra, Mahajanga Province. Rahonavis was a small predator, at about 70 centimetres (2.3 ft) long and 0.45-2.27 kg, with the typical dromaesaurid-like raised sickle claw on the second toe. It was originally the first African coelurosaur until the discovery of Nqwebasaurus in 2000.

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

Pyroraptor is an extinct genus of paravian dinosaur, probably a dromaeosaurid or unenlagiid, from the Late Cretaceous Ibero-Armorican island, of what is now southern France. It lived during the late Campanian and early Maastrichtian stages, approximately 72 million years ago. It is known from a single partial specimen that was found in Provence in 1992, after a forest fire. The animal was named Pyroraptor olympius by Allain and Taquet in 2000.

Unenlagia is a genus of dromaeosaurid theropod dinosaur that lived in South America during the Late Cretaceous period. The genus Unenlagia has been assigned two species: U. comahuensis, the type species described by Novas and Puerta in 1997, and U. paynemili, described by Calvo et al. in 2004.

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

Patagonykus is a genus of theropod dinosaur from the Upper Cretaceous of Argentina. This alvarezsauroid was discovered in exposures of the Portezuelo Formation (Turonian-Coniacian) of the Rio Neuquén Subgroup in the Neuquén Basin, Neuquen Province of Patagonia, Argentina. The holotype consists of an incomplete but well-preserved skeleton, lacking a skull, but including many vertebrae, the coracoids, a partial forelimb, pelvic girdle, and hindlimbs. Patagonykus has been classed with the Alvarezsauridae, a family which includes such taxa as the Mongolian Mononykus and the Argentinian Alvarezsaurus. In 2010 Gregory S. Paul estimated its length at 1 meter and its weight at 3.5 kg.

The Huincul Formation is a geologic formation of Late Cretaceous age of the Neuquén Basin that outcrops in the Mendoza, Río Negro and Neuquén Provinces of northern Patagonia, Argentina. It is the second formation in the Río Limay Subgroup, the oldest subgroup within the Neuquén Group. Formerly that subgroup was treated as a formation, and the Huincul Formation was known as the Huincul Member.

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

Unenlagiinae is a subfamily of long-snouted paravian theropods. They are traditionally considered to be members of Dromaeosauridae, though some authors place them into their own family, Unenlagiidae, sometimes alongside the subfamily Halszkaraptorinae. Definitive members are known from South America, though some researchers include taxa from other continents within this subfamily based on phylogenetic analyses.

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

Shanag is a genus of paravian theropod dinosaur from the Early Cretaceous Period of Mongolia. It may be a dromaeosaurid, but some researchers are skeptical of this classification. The type species is S. ashile.

<i>Austroraptor</i> Genus of theropod dinosaurs

Austroraptor is a genus of dromaeosaurid theropod dinosaur that lived during the Campanian and Maastrichtian ages of the Late Cretaceous period in what is now Argentina.

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

Tianyuraptor is a genus of short-armed dromaeosaurid dinosaur that lived during the Early Cretaceous, about 122 million years ago. Its remains have been found in western Liaoning, China. It was similar to other dromaeosaurids found in Liaoning, with the exception of being somewhat more primitive. The type specimen, formally named in 2009, shows features not seen in previously known Northern Hemisphere (Laurasian) dromaeosaurids, but present in Southern Hemisphere (Gondwanan) species and early birds. Because of this, the scientists who first studied Tianyuraptor described it as a "transitional species", bridging the gap between northern and southern types of dromaeosaurid. Tianyuraptor also differs from previously known dromaeosaurids in that it possesses a relatively small furcula ("wishbone"), and unusually short forelimbs.

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

Pamparaptor is an extinct genus of paravian theropod dinosaur from the Late Cretaceous Portezuelo Formation of the Neuquén province in Argentine Patagonia. Its precise classification is uncertain, but the authors who described this taxon have argued that it is a dromaeosaurid. The genus contains a single species, P. micros, which is known from a single specimen consisting of a mostly complete and fully-articulated left foot, which preserves the iconic dromaeosaur-like "killing claw".

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

Alnashetri is an extinct genus of alvarezsaurid coelurosaurian theropod dinosaur known from the early Late Cretaceous of La Buitrera, Río Negro Province, Argentina. It contains one known species, Alnashetri cerropoliciensis. Its remains were discovered in Candeleros Formation.

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

This timeline of dromaeosaurid research is a chronological listing of events in the history of paleontology focused on the dromaeosaurids, a group of sickle-clawed, bird-like theropod dinosaurs including animals like Velociraptor. Since the Native Americans of Montana used the sediments of the Cloverly Formation to produce pigments, they may have encountered remains of the dromaeosaurid Deinonychus hundreds of years before these fossils came to the attention of formally trained scientists.

<span class="mw-page-title-main">Unenlagiidae</span> Extinct family of dinosaurs

Unenlagiidae is a proposed family of eumaniraptoran paravians that includes the subfamilies Unenlagiinae and possibly Halszkaraptorinae. Fossils of both subfamilies have been found in both Gondwanan and Laurasian deposits. The biology of the group suggests that some members were semiaquatic specialists.

Tralkasaurus is a genus of abelisaurid dinosaur from the Huincul Formation from Río Negro Province in Argentina. The type and only species is Tralkasaurus cuyi, named in 2020 by Mauricio Cerroni and colleagues based on an incomplete skeleton. A medium-sized abelisaurid, Tralkasaurus exhibits a conflicting blend of characteristics found among the early-diverging abelisauroids with others that characterize the highly specialized clade Brachyrostra, and thus its position within the clade is poorly-resolved.

<i>Overoraptor</i> Extinct genus of theropod dinosaurs

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<i>Meraxes</i> Genus of carcharodontosaurid dinosaurs

Meraxes is a genus of large carcharodontosaurid theropod dinosaur from the Late Cretaceous Huincul Formation of Patagonia, Argentina. The genus contains a single species, Meraxes gigas.

<i>Chucarosaurus</i> Genus of titanosaurian dinosaurs

Chucarosaurus is an extinct genus of titanosaurian dinosaur from the Late Cretaceous Huincul Formation of Argentina. The genus contains a single species, C. diripienda, known from various limb and pelvic bones.

References

  1. 1 2 3 4 5 6 Makovicky, Peter J.; Apesteguía, Sebastián; Agnolín, Federico L. (2005). "The earliest dromaeosaurid theropod from South America". Nature. 437 (7061): 1007–1011. Bibcode:2005Natur.437.1007M. doi:10.1038/nature03996. PMID   16222297. S2CID   27078534.
  2. Gianechini, Federico A.; Makovicky, Peter J.; Apesteguía, Sebastián (2017-01-02). "The cranial osteology of Buitreraptor gonzalezorum Makovicky, ApesteguÍa, and AgnolÍn, 2005 (Theropoda, Dromaeosauridae), from the Late Cretaceous of Patagonia, Argentina". Journal of Vertebrate Paleontology. 37 (1): e1255639. Bibcode:2017JVPal..37E5639G. doi:10.1080/02724634.2017.1255639. ISSN   0272-4634. S2CID   89993518.
  3. 1 2 3 Novas, Fernando E.; Brissón Egli, Federico; Agnolin, Federico L; Gianechini, Federico A.; Cerda, Ignacio (2018-03-01). "Postcranial osteology of a new specimen of Buitreraptor gonzalezorum (Theropoda, Unenlagiidae)". Cretaceous Research. 83: 127–167. Bibcode:2018CrRes..83..127N. doi:10.1016/j.cretres.2017.06.003. ISSN   0195-6671.
  4. Motta, Matías J.; Brissón Egli, Federico; Novas, Fernando E. (2018-03-01). "Tail anatomy of Buitreraptor gonzalezorum (Theropoda, Unenlagiidae) and comparisons with other basal paravians". Cretaceous Research. 83: 168–181. Bibcode:2018CrRes..83..168M. doi:10.1016/j.cretres.2017.09.004. ISSN   0195-6671.
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  6. Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 139
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  8. 1 2 Gianechini, F.A.; Makovicky, P.J; Apesteguía, S. (2011). "The teeth of the unenlagiine theropod Buitreraptor from the Cretaceous of Patagonia, Argentina, and the unusual dentition of the Gondwanan dromaeosaurids". Acta Palaeontologica Polonica. 56 (2): 279–290. doi: 10.4202/app.2009.0127 . hdl: 11336/192712 .
  9. National Geographic : "New Birdlike Dino Adds to Debate on Origins of Flight", 18-10-2005.
  10. New Scientist : "Feathered flight, so good they did it twice?", 15-10-2005.
  11. Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight". PeerJ. 7: e7247. doi: 10.7717/peerj.7247 . PMC   6626525 . PMID   31333906.
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  13. Hu, D.; Hou, L.; Zhang, L. & Xu, X. (2009), "A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus", Nature, 461 (7264): 640–643, Bibcode:2009Natur.461..640H, doi:10.1038/nature08322, PMID   19794491, S2CID   205218015
  14. Motta, Matías J.; Brissón Egli, Federico; Novas, Fernando E. (2018-03-01). "Tail anatomy of Buitreraptor gonzalezorum (Theropoda, Unenlagiidae) and comparisons with other basal paravians". Cretaceous Research. New Insights on the Vertebrate Paleontology of the Neuquén Group, Patagonia, Argentina. 83: 168–181. Bibcode:2018CrRes..83..168M. doi:10.1016/j.cretres.2017.09.004. ISSN   0195-6671.
  15. Gianechini, Federico A.; Makovicky, Peter J.; Apesteguía, Sebastián (2017-01-02). "The cranial osteology of Buitreraptor gonzalezorum Makovicky, ApesteguÍa, and AgnolÍn, 2005 (Theropoda, Dromaeosauridae), from the Late Cretaceous of Patagonia, Argentina". Journal of Vertebrate Paleontology. 37 (1): e1255639. Bibcode:2017JVPal..37E5639G. doi:10.1080/02724634.2017.1255639. ISSN   0272-4634. S2CID   89993518.
  16. Novas, Fernando E.; Brissón Egli, Federico; Agnolin, Federico L.; Gianechini, Federico A.; Cerda, Ignacio (2018-03-01). "Postcranial osteology of a new specimen of Buitreraptor gonzalezorum (Theropoda, Unenlagiidae)". Cretaceous Research. New Insights on the Vertebrate Paleontology of the Neuquén Group, Patagonia, Argentina. 83: 127–167. Bibcode:2018CrRes..83..127N. doi:10.1016/j.cretres.2017.06.003. ISSN   0195-6671.
  17. Gianechini, F. A.; Ercoli, M. D.; Díaz-Martinez, I. (2020). "Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies". Journal of Anatomy. 236 (5): 772−797. doi:10.1111/joa.13153. PMC   7163733 . PMID   32023660.