Buitreraptor
Encyclopedia
Buitreraptor is a predatory dromaeosaurid theropod dinosaur
from the Cretaceous
of Argentina
.
Buitreraptor was described in 2005. The type species
is Buitreraptor gonzalezorum. It was rooster-sized and had a very elongated head with many small teeth.
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
, about 94 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 Giganotosaurus
, one of the largest known carnivorous dinosaurs.
Buitreraptor gonzalezorum is the only known species of the genus
Buitreraptor. It was named by Macovicky, 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 brethren Fábian and Jorge González who realised much of the actual excavation and preparation of the fossils.
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. The two other specimens have remained undescribed.
estimated the length at 1.5 metres, the weight at three kilograms.
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. 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 lizard
s and mammal
s. The forelimbs of Buitreraptor were long and ending in hands with three fingers. The fingers were proportionarly shorter than in other dromaeosaurids, and of essentially the same length, contrary to most of its relatives, which had fingers of different length, with the second finger being considerably longer.
The body as a whole was also very elongated, with a shallow ribcage. The sickle claw at the second toe of the foot was relatively short and broad.
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.
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. However, other paleontologists have in later studies placed the time of origin for dromaeosauridae to about 160 million years ago.
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, iguania
n lizards, chelid
turtles, mammals, and dipnoan
fishes
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
.
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.
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
from the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
of Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
.
Buitreraptor was described in 2005. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Buitreraptor gonzalezorum. It was rooster-sized and had a very elongated head with many small teeth.
Discovery and naming
Four skeletons of Buitreraptor were found in 2004 in sandstoneSandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
in Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
, Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
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
Field Museum of Natural History
The Field Museum of Natural History is located in Chicago, Illinois, USA. It sits on Lake Shore Drive next to Lake Michigan, part of a scenic complex known as the Museum Campus Chicago...
.
Buitreraptor is from the early Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
Candeleros Formation
Candeleros Formation
The Candeleros Formation is a geologic formation that outcrops in Río Negro, Neuquén, and Mendoza provinces of Argentina. It is the oldest formation in the Neuquén Group and belongs to the Rio Limay Subgroup...
, dating to the Cenomanian
Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...
-Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
, about 94 million years ago, when South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
was an isolated continent like Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
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 Giganotosaurus
Giganotosaurus
Giganotosaurus is a genus of carcharodontosaurid dinosaur that lived around 97 million years ago during the early Cenomanian stage of the Late Cretaceous Period. It included some of the largest known terrestrial carnivores, slightly larger than the largest Tyrannosaurus, but smaller than the...
, one of the largest known carnivorous dinosaurs.
Buitreraptor gonzalezorum is the only known species of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Buitreraptor. It was named by Macovicky, Apesteguía and Federico Agnolín. The genus name means "vulture raider", from the Spanish word buitre meaning vulture
Vulture
Vulture is the name given to two groups of convergently evolved scavenging birds, the New World Vultures including the well-known Californian and Andean Condors, and the Old World Vultures including the birds which are seen scavenging on carcasses of dead animals on African plains...
, in reference to La Buitrera, and Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
raptor, "seizer". The specific name honours the brethren Fábian and Jorge González who realised much of the actual excavation and preparation of the fossils.
The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
specimen, MPCA 245, consists of a partial skeleton with skull of an adult individual. The paratype
Paratype
Paratype is a technical term used in the scientific naming of species and other taxa of organisms. The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany...
is MPCA 238, a sacrum with a right pelvis and right hindlimb. The two other specimens have remained undescribed.
Description
Buiteraptor was a rather small species. In 2010 Gregory S. PaulGregory S. Paul
Gregory Scott Paul is a freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dinosaurs and his detailed illustrations, both live and skeletal...
estimated the length at 1.5 metres, the weight at three kilograms.
Buitreraptor has some different physical features than typical northern dromaeosaurs, such as Velociraptor
Velociraptor
Velociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 million years ago during the later part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils...
.
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. 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 lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s and mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. The forelimbs of Buitreraptor were long and ending in hands with three fingers. The fingers were proportionarly shorter than in other dromaeosaurids, and of essentially the same length, contrary to most of its relatives, which had fingers of different length, with the second finger being considerably longer.
The body as a whole was also very elongated, with a shallow ribcage. The sickle claw at the second toe of the foot was relatively short and broad.
Feathers
No fossil discoveries have been made of any feathers of Buitreraptor. However, there are relatives like MicroraptorMicroraptor
Microraptor is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China...
and Sinornithosaurus
Sinornithosaurus
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...
, 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
Monkey
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
with fur
Fur
Fur is a synonym for hair, used more in reference to non-human animals, usually mammals; particularly those with extensives body hair coverage. The term is sometimes used to refer to the body hair of an animal as a complete coat, also known as the "pelage". Fur is also used to refer to animal...
because all modern monkeys have fur.
Paleobiogeography
Neuquenraptor
Neuquenraptor is a dromaeosaurid theropod dinosaur of the Late Cretaceous of Argentina, one of the first dromaeosaurids found in the Southern Hemisphere....
, Austroraptor
Austroraptor
Austroraptor was a genus of dromaeosaurid dinosaur that lived about 70 million years ago during the Cretaceous period in what is now modern Argentina. The type species for the genus, Austroraptor cabazai, was described in late 2008 by Fernando Novas of the Museo Argentino de Ciencias Naturales...
, and Unenlagia
Unenlagia
Unenlagia is a genus of, possibly dromaeosaurid, theropod dinosaur from the Late Cretaceous of Argentina....
from South America (discovered earlier in 2005), Rahonavis
Rahonavis
Rahonavis is a genus of bird-like dinosaur from the Late Cretaceous of what is now northwestern Madagascar. It is known from a partial skeleton found in Maevarano Formation rocks at a quarry near Berivotra, Mahajanga Province...
(once thought to be a true avian bird) from Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, 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
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
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
Pangaea
Pangaea, Pangæa, or Pangea is hypothesized as a supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration....
broke up. However, other paleontologists have in later studies placed the time of origin for dromaeosauridae to about 160 million years ago.
The scientists see it as an alternative possibility that dromaeosaurids originated on the ancient continent Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...
in the north and during the Cretaceous Period migrated to southern Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
, 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, iguania
Iguania
Iguania is the suborder of Squamata that contains the iguanas, chameleons, agamids, and "New World lizards" such as anoles and Phrynosomatidae...
n lizards, chelid
Chelidae
The Chelidae are one of the three living families of the turtle suborder Pleurodira and are commonly called the Austro-South American Side Neck turtles. The Family is distributed in Australia, New Guinea, parts of Indonesia and throughout most of South America. It is a large family of turtles with...
turtles, mammals, and dipnoan
Lungfish
Lungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...
fishes
Phylogeny and discussion about flight
Buitreraptor shows a mosaic of dromaeosaurid, troodontidTroodontidae
Troodontidae is a family of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and scrappy and they have therefore been allied, at various times, with many dinosaurian lineages...
and avialan
Avialae
Avialae is a clade of dinosaurs containing their only living representatives, birds , and the most immediate extinct relatives of birds.-Competing definitions:...
traits. It was in 2005 assigned to the Dromaeosauridae
Dromaeosauridae
Dromaeosauridae is a family of bird-like theropod dinosaurs. They were small- to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek dromeus meaning 'runner' and sauros meaning 'lizard'...
. A cladistic analysis by the describers showed it was part of the dromaeosaurid Unenlagiinae
Unenlagiinae
Unenlagiinae is a subfamily of Dromaeosauridae. Unenlagiines are one of the most basal lineages of dromaeosaurids. Unenlagiines are known from South America and Madagascar....
.
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
Rahonavis
Rahonavis is a genus of bird-like dinosaur from the Late Cretaceous of what is now northwestern Madagascar. It is known from a partial skeleton found in Maevarano Formation rocks at a quarry near Berivotra, Mahajanga Province...
, 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.
External links
- BBC News: Bird-like dinosaur forces rethink, 13-Oct-2005
- Drawing and some details from the Natural History Museum, London.
- National Science Foundation web site