''Buitreraptor'' (meaning "La Buitrera seizer") is a genus of
dromaeosaurid
Dromaeosauridae () is a family of feathered 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 ('), meaning ...
dinosaurs
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
that lived during the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
of
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
at the
Candeleros Formation
The Candeleros Formation (formerly known as the Candeleros Member of the "Río Limay Formation") is a geologic formation that crops out in the Río Negro, Neuquén, and Mendoza provinces of northern Patagonia, Argentina. It is the oldest formati ...
. ''Buitreraptor'' was described in 2005 and the
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
is ''Buitreraptor gonzalezorum''. It was rooster-sized and had a very elongated head with many small teeth.
History of discovery
![Buitreraptor gonzalezorum](https://upload.wikimedia.org/wikipedia/commons/c/ce/Buitreraptor_gonzalezorum.jpg)
Four specimens of ''Buitreraptor'' were found in 2004 in
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates) ...
in
Patagonia,
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
during an excavation led by
Sebastián Apesteguia, researcher of CONICET at the
Fundacion Felix de Azara - Maimonides University, and
Peter Makovicky
Peter may refer to:
People
* List of people named Peter, a list of people and fictional characters with the given name
* Peter (given name)
** Saint Peter (died 60s), apostle of Jesus, leader of the early Christian Church
* Peter (surname), a sur ...
, curator of dinosaurs at the
Field Museum in Chicago. ''Buitreraptor'' is from the early
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
Candeleros Formation
The Candeleros Formation (formerly known as the Candeleros Member of the "Río Limay Formation") is a geologic formation that crops out in the Río Negro, Neuquén, and Mendoza provinces of northern Patagonia, Argentina. It is the oldest formati ...
, dating to the
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 s ...
-
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 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...
ages approximately 98 to 97 million years ago, when
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
was an isolated continent like
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
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.
''Buitreraptor gonzalezorum'' is the only known species of the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''Buitreraptor''. It was named by Peter Makovicky, Sebastián Apesteguía and
Federico Agnolín Federico (; ) is a given name and surname. It is a form of Frederick, most commonly found in Spanish, Portuguese and Italian.
People with the given name Federico
Artists
* Federico Ágreda, Venezuelan composer and DJ.
* Federico Aguilar Alcuaz, ...
. The genus name means "vulture raider", from the Spanish word ''buitre'' meaning
vulture
A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture (including Condors). Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to North and ...
, in reference to ''La Buitrera'', and
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''raptor'', "seizer". The
specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
honours the González brothers, Fábian and Jorge, who realised much of the actual excavation and preparation of the fossils.
The
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...
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 skull of the holotype was described in detail in 2017, while 2018 saw a slew of new papers on the anatomy of the genus. These include descriptions of new specimens,
a study on the tail anatomy of the genus, and a general overview of the
postcrania Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...
of multiple specimens.
Description
![Buitreraptor gonzalezorum size chart](https://upload.wikimedia.org/wikipedia/commons/b/b7/Buitreraptor_gonzalezorum_size_chart.png)
''Buitreraptor'' was a rather small dinosaur. In 2010,
Gregory S. Paul 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'' (; ) is a genus of small dromaeosaurid dinosaur that lived in Asia during the Late Cretaceous epoch, about 75 million to 71 million years ago. Two species are currently recognized, although others have been assigned in the pa ...
''. ''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
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...
s and
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s. 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
''Velociraptor'' (; ) is a genus of small dromaeosaurid dinosaur that lived in Asia during the Late Cretaceous epoch, about 75 million to 71 million years ago. Two species are currently recognized, although others have been assigned in the pa ...
'', except for the ungual bones which are proportionally smaller in ''Buitreraptor''.
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''.
No fossil discoveries have been made of any feathers of ''Buitreraptor''. However, there are relatives like ''
Microraptor
''Microraptor'' (Greek, μικρός, ''mīkros'': "small"; Latin, ''raptor'': "one who seizes") is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China. They dat ...
'' and ''
Sinornithosaurus
''Sinornithosaurus'' (derived from a combination of Latin and Greek, meaning 'Chinese bird-lizard') is a genus of feathered dromaeosaurid dinosaur from the early Cretaceous Period (late Barremian) of the Yixian Formation in what is now China. It ...
'', 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 is a common name that may refer to most mammals of the infraorder Simiiformes, also known as the simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes, which constitutes an incomple ...
with
fur
Fur is a thick growth of hair that covers the skin of mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an insulating blanket t ...
because all modern monkeys have fur.
['']National Geographic
''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...
''
"New Birdlike Dino Adds to Debate on Origins of Flight"
18-10-2005.
Classification
![Reconstrucción Buitreraptor gonzalezorum](https://upload.wikimedia.org/wikipedia/commons/3/30/Reconstrucci%C3%B3n_Buitreraptor_gonzalezorum.jpg)
''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.
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'' is a genus of bird-like theropods from the Late Cretaceous (Maastrichtian, about 70 mya) of what is now northwestern Madagascar. It is known from a partial skeleton ( UA 8656) found by Catherine Forster and colleagues in Maevarano ...
'', 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.
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":
Evolution
Other than ''Buitreraptor'', the only other known dromaeosaurs from the southern continents are ''
Neuquenraptor
''Neuquenraptor'' (meaning Neuquén thief) 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 ...
'', ''
Austroraptor
''Austroraptor'' ( ) is a genus of large dromaeosaurid dinosaur that lived during the Late Cretaceous Period in what is now Argentina.
''Austroraptor'' was a large-sized, moderately-built, ground-dwelling, bipedal carnivore, estimated at in len ...
'', and ''
Unenlagia'' from South America (discovered earlier in 2005), ''
Rahonavis
''Rahonavis'' is a genus of bird-like theropods from the Late Cretaceous (Maastrichtian, about 70 mya) of what is now northwestern Madagascar. It is known from a partial skeleton ( UA 8656) found by Catherine Forster and colleagues in Maevarano ...
'' (once thought to be a true avian bird) from
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East 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
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
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.
[''EurekAlert!'']
"Newly discovered birdlike dinosaur is oldest raptor ever found in South America: Relative of ''Velociraptor'' rewrites evolutionary charts"
12-10-2005. 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 () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pan ...
in the north and during the Cretaceous Period migrated to southern
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...
, 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
rhynchocephalia
Rhynchocephalia (; ) is an order of lizard-like reptiles that includes only one living species, the tuatara (''Sphenodon punctatus'') of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a diverse g ...
ns, limbed snakes,
iguanian lizards,
chelid
Chelidae is one of three living families of the turtle suborder Pleurodira, and are commonly called Austro-South American side-neck turtles. The family is distributed in Australia, New Guinea, parts of Indonesia, and throughout most of South Amer ...
turtles, mammals, and
dipnoan fishes
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
A cursorial organism is one that is adapted specifically to run. An animal can be considered cursorial if it has the ability to run fast (e.g. cheetah) or if it can keep a constant speed for a long distance (high endurance). "Cursorial" is often u ...
animals because they were more gracile and had modified metatarsals that are relatively thin and lengthened. Based on these adaptations, it is likely that unenlagiines preyed on small, fast animals, although the exact animals are unknown. ''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.
See also
*
Timeline of dromaeosaurid research
References
External links
BBC News: Bird-like dinosaur forces rethink 13-Oct-2005
Drawing and some detailsfrom the Natural History Museum, London.
National Science Foundation web site
{{Taxonbar, from=Q133137
Unenlagiines
Late Cretaceous dinosaurs of South America
Cretaceous Argentina
Fossils of Argentina
Candeleros Formation
Fossil taxa described in 2005