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Description
Buitreraptor gonzalezorum

Dromaeosaurs have no shortage of iconic and terrifying animals. From the giant Utahraptor to the ferocious Deinonychus, and most famous from Jurassic Park, Velociraptor. The lattermost was scaled to be over 6ft tall and around 12-15ft long. Velociraptor was no larger than a turkey at just 6ft long and 2ft tall—a far cry from the giant raptor villain from the Jurassic Franchise. However, an even smaller and bizarre animal was unearthed from South America in the intervening years. Around 1/5 the size of Velociraptor, the animal was dubbed Buitreraptor gonzalezorum.

History of Discovery:

In 2004, a joint US-Argentinian team was excavating in the Candeleros Formation prospecting for dinosaur fossils in the heart of Patagonia. The team led by Sebastián Apesteguia of Maimonides University in Argentina and Peter Makovicky of the Field Museum in Chicago were prospecting throughout the formation and had largely been a fruitless excavation. A handful of bone fragments were found, but nothing significant. At the time, Candeleros was a somewhat spotty formation in terms of dinosaur fossils, and more complete specimens often eluded them. The most famous find from the region was Giganotosaurus, discovered nine years prior with a partial skull and around 40-50% of the skeleton found.

Makovicky and Apesteguia's team searched in a region called "La Buitrera" or "The Vulture's Roost". It had been largely devoid of fossils, but a nearby site had yielded the holotype specimen of Giganotosaurus. And this year, luck would be on their side. Two brothers who assisted in a lot of these excavations, the González brothers, Fábian and Jorge, were the ones who found something that would make this excavation truly important. On the side of the hillside in La Buitrera, they unearthed a tiny skeleton of what they thought was a bird, but as they dug into the rock, they realized that this was far more significant: a small dromaeosaur. The specimen was described fairly quickly, roughly a year after the brothers discovered it, the animal was described by Makovicky and Apesteguia.

They named the new dromaeosaur Buitreraptor gonzalezorum, the generic name after the site, "La Buitrera," and "raptor," the Latin meaning "thief" or "seizer." The specific name is in reference to the discoverers, the Gonzalez brothers. So, the entire name is "The Gonzalez's Vulture's Roost Thief".

The holotype (specimen #: MPCA 245) is a nearly complete specimen that consists of a partial forelimb, an incomplete skull, part of the tail, and a decently preserved torso and left hindlimb with a complete foot. They also found more material with a sacrum and right hindlimb, which is the paratype (specimen #: MPCA 238). Some think this may be the same as the holotype, but as it stands, they're primarily believed to be distinct. In the intervening years, the holotype was redescribed, and studies on the animal were conducted, including a description of the skull and the tail and primarily conducted by both Makovicky and Apesteguia who sought to reanalyze the specimen with a more modern understanding of dromaeosaur evolution.

As of 2024, this is the most complete specimen of any dinosaur unearthed from Candeleros with around 75% of the specimen(s) recovered with both the holotype and paratype.

Description:

Buitreraptor was a small dromaeosaur. Among the smallest outside of dromaeosaurs like animals in Microraptoria. At only 4-4.9ft long, 0.7-1ft tall, this was a diminutive raptor compared to even animals like Velociraptor. It perhaps weighed no more than some mid-sized chickens around 4-6lbs. While no feather impressions or osteological correlates (quill knobs with Velociraptor) have been found, given the prevalence of feathers in dromaeosaurs, and its small size, it's basically a given that this tiny raptor had feathers.

Like all dromaeosaurs, it has an enlarged digit 1 claw however, whether it was used for dispatching prey is a subject of debate given it wasn't as recurved. Despite its small size, proportionally, the legs were longer than its northern relatives. Suggesting a more cursorial mode of locomotion. Even more intriguing is that this animal had what appeared to be a sub-arctometatarsal foot bone construction. An arctometatarsal is a condition present among Tyrannosaurs, Ornithomimids, and Troodontids. It's when the inner and outer metatarsal pinch the one in the center together. A feature like this assists animals in agility and likely has implications for how this animal moved.

A feature unique to Buitreraptor and its subfamily compared to other dromaeosaurs was its narrow and elongated skull. The skull was filled with teeth which were miniscule and lack the serrations of their northern relatives but are recurved, yet flat. A feature that will be discussed later.

Classification:

Buitreraptor is a member of the unenlagiinae. A subfamily of dromaeosaurs that have been found largely in South America. There is debate as to whether they were found in other regions in the southern hemisphere. With fragmentary fossils being found in Africa and Australia being attributed to them. Some even think that dromaeosaurs like Pyroraptor being theorized to be one, or even in North America with animals like Dakotaraptor being posited to be an unenlagiine (now believed to be untrue).

The type genus, Unenlagia itself was discovered in the 90s and identified as a dromaeosaur. In 1999, the legendary Argentinian paleontologist José Fernando Bonaparte described the subfamily as being distinctive to its northern kin as it had longer legs, less stocky build, and a differently shaped pubis, however, this was largely circumstantial. It wouldn't be until Buitreraptor was discovered that Bonaparte's theory was vindicated. With a pubis similar to Unenlagia, it was classified as an unenlagiine.

Buitreraptor helped shed light on these more bizarre South American paravians. Not only were these animals more lightly built, as previously stated, they had a sub-arctometatarsalian condition. Furthermore, the animals had a longer and more stiffened tail compared to animals like Velociraptor and Deinonychus. With animals like Buitreraptor and the giant Austroraptor having skull material discovered, it shows these animals had an elongated skull, even more so than Velociraptor and it had a narrow rostrum with lightly built, but recurved teeth. Finally, the foot bones were smaller and less robustly built compared to their northern relatives.

It's likely due to South America being isolated, dromaeosaurs became adapted to a different niche. Not becoming powerful ambush hunters but filling a reduced role in their ecosystems as many were small animals and lived in the shadow of larger predators like carcharodontosaurs and abelisaurs.

Implications of Unenlagiine behavior:

Dromaeosaurs as a whole have been described as being powerful ambush hunters. It's now believed that many northern dromaeosaurs ambushed their prey, pined them down with their claws and then picked at it while still alive with the victim dying of shock and organ failure. This is known as Raptor Prey Restraint. Despite being shown as fast predators, dromaeosaurs with their heavily built feet and leg construction likely made northern dromaeosaurs strong to avg. speed ambush predators, likely about as fast as an average runner around 15-22mph. Fast, but about as fast as a fit human.

Buitreraptor and its kin, the unenlagiines were very different. With their sub-arctometatarsalian condition, it implies these animals were more cursorial and agile. These animals could have been speedy predators designed to run down prey. They were probably adapted to be not only more agile, but with their longer limbs they were also faster perhaps reaching speeds equivalent to the fastest birds or non-avian dinosaurs. However, there was a trade-off with this agility.

For one the foot bones were lithe and not as robust as their northern kin, the hinges were not as powerful, and it suggests that these animals could not perform raptor prey restraint. The infamous sickle claw was not as recurved and perhaps couldn't have been used to puncture prey effectively. Moreover, with its longer head, teeth that lack serrations its likely they couldn't even kill larger prey. Why would such a narrow skull evolve among these dromaeosaurs?

Given its more agile nature and skull build, it's likely that Buitreraptor and its kin hunted small mammals, lizards, or animals they could have gotten down in one go. How they dispatched prey is unknown, they could have done a reduced form of RPR or, they could have done something different. Animals like the modern South American seriema kill small lizards and mammals by picking them up and then slamming it down to the ground. seriema are also fast runners and like most birds of prey, they have a sickle claw, but it is also reduced. Perhaps this could be a modern analogue to what unenlagiines were like.

Habitat:

Buitreraptor resided in the Candeleros Formation around 99-97,000,000 years ago. The environment would have been an arid mountainous environment similar to parts of modern Patagonia, but it would have been warmer, with rivers crisscrossing the environment. Conifers, cycad and horsetail would have been the prominent flora in the region.

Buitreraptor was a small animal in this ecosystem. It shared this environment with sauropods with animals like Limaysaurus, Rayososaurus being smaller sauropods 10-12 tons they were members of the rebbachisauridae, more derived diplodocids. The titans of the region were the titanosaurs with animals like Andesaurus roaming the fern prairies and forests weighing some 20-25 tons. However, in 2021, a giant titanosaur was discovered being the equivalent to Patagotitan and Argentinosaurus, perhaps weighing 50-70 tons. Even more recently was the tiny and primitive thyreophoran Jakapil similar to early Jurassic forms.

Trace fossils of iguanodonts of varying sizes have been found in the formation with some fragments also being found.

Alongside Buitreraptor were predators that thrived in this environment. The largest and most famous resident would undoubtedly be Giganotosaurus. The 40-45ft predator was the apex predator in the region hunting the sauropods and larger ornithopods in the region. Ekrixinatosaurus a large Abelisaur was also found here.

Buitreraptor scampered beneath these titans and hunted smaller animals. Among them would have been primitive lizards and rhynchocephalians (relatives of the Tuatara) like Tika and Priosphenodon. Furthermore, a small mammal called Cronopio was present here too. Hunting these lizards and mammals would have been easy pickings for this agile raptor. With its narrow jaws and recurved teeth, if it caught one of these mammals or lizards in its maw, it would have hooked them and Buitreraptor could have either swallowed it whole or behaved like seriemas and smashed them to the ground.

Competing directly with them and of similar size was the terrestrial crocodilian Araripesuchus. A sebecid that was around the size of a coyote and could've filled a similar niche to Buitreraptor. However, hatchlings could've been on the menu for this agile raptor as well.

Extinction:

Why Buitreraptor died off is unknown. Perhaps due to climate change and that caused this peculiar raptor to die off and be replaced by more derived members of unenlagiines some 97-96,000,000 years ago.

Despite the fact it's now gone, Buitreraptor offered an insight into the evolution and looks of this group of southern dromaeosaurs. With its description back in 2004, it solidified the distinctiveness of unenlagiines being a unique subfamily of dromaeosaurs. With a slew of adaptations designed to occupy a different niche than its northern relatives and become not a powerful ambush predator, but a lithe and swift pursuit hunter tackling smaller prey. Buitreraptor is another example of how diverse and unique prehistoric life is.
___________________________________________________________________________________________
Okay, this one was kind of easy, I decided to redo the old Buitreraptor profile I did about two years ago.

Mainly because it was done when I was still learning the basics of skinning and I also wanted to update the

I've seen a skeleton of Buitreraptor countless times at the Field Museum right next to Deinonychus. Buitreraptor is easily one of my favorite dromaeosaurs and I thought I'd write up a brief profile on this animal with a dueling pose between two individuals. A rather basic skin, but... eh... I still like this pose I gave both of these guys.

Will this be in PMP? Yes. I've made up my mind and we will be rescuing animals from Candeleros Patagonia. Will Buitreraptor be among them? You'll find out...

Original model and skin made by Ulquiorra and Lgcfm, modified by me:
Velociraptor (Lgcfm & Ulquiorra) | ZT2 Download Library Wiki | Fandom

Araripesuchus hatchling by DemonHunterZT2 thanks a ton for this Croc!

Description
Buitreraptor gonzalezorum

Dromaeosaurs have no shortage of iconic and terrifying animals. From the giant Utahraptor to the ferocious Deinonychus, and most famous from Jurassic Park, Velociraptor. The lattermost was scaled to be over 6ft tall and around 12-15ft long. Velociraptor was no larger than a turkey at just 6ft long and 2ft tall—a far cry from the giant raptor villain from the Jurassic Franchise. However, an even smaller and bizarre animal was unearthed from South America in the intervening years. Around 1/5 the size of Velociraptor, the animal was dubbed Buitreraptor gonzalezorum.

History of Discovery:

In 2004, a joint US-Argentinian team was excavating in the Candeleros Formation prospecting for dinosaur fossils in the heart of Patagonia. The team led by Sebastián Apesteguia of Maimonides University in Argentina and Peter Makovicky of the Field Museum in Chicago were prospecting throughout the formation and had largely been a fruitless excavation. A handful of bone fragments were found, but nothing significant. At the time, Candeleros was a somewhat spotty formation in terms of dinosaur fossils, and more complete specimens often eluded them. The most famous find from the region was Giganotosaurus, discovered nine years prior with a partial skull and around 40-50% of the skeleton found.

Makovicky and Apesteguia's team searched in a region called "La Buitrera" or "The Vulture's Roost". It had been largely devoid of fossils, but a nearby site had yielded the holotype specimen of Giganotosaurus. And this year, luck would be on their side. Two brothers who assisted in a lot of these excavations, the González brothers, Fábian and Jorge, were the ones who found something that would make this excavation truly important. On the side of the hillside in La Buitrera, they unearthed a tiny skeleton of what they thought was a bird, but as they dug into the rock, they realized that this was far more significant: a small dromaeosaur. The specimen was described fairly quickly, roughly a year after the brothers discovered it, the animal was described by Makovicky and Apesteguia.

They named the new dromaeosaur Buitreraptor gonzalezorum, the generic name after the site, "La Buitrera," and "raptor," the Latin meaning "thief" or "seizer." The specific name is in reference to the discoverers, the Gonzalez brothers. So, the entire name is "The Gonzalez's Vulture's Roost Thief".

The holotype (specimen #: MPCA 245) is a nearly complete specimen that consists of a partial forelimb, an incomplete skull, part of the tail, and a decently preserved torso and left hindlimb with a complete foot. They also found more material with a sacrum and right hindlimb, which is the paratype (specimen #: MPCA 238). Some think this may be the same as the holotype, but as it stands, they're primarily believed to be distinct. In the intervening years, the holotype was redescribed, and studies on the animal were conducted, including a description of the skull and the tail and primarily conducted by both Makovicky and Apesteguia who sought to reanalyze the specimen with a more modern understanding of dromaeosaur evolution.

As of 2024, this is the most complete specimen of any dinosaur unearthed from Candeleros with around 75% of the specimen(s) recovered with both the holotype and paratype.

Description:

Buitreraptor was a small dromaeosaur. Among the smallest outside of dromaeosaurs like animals in Microraptoria. At only 4-4.9ft long, 0.7-1ft tall, this was a diminutive raptor compared to even animals like Velociraptor. It perhaps weighed no more than some mid-sized chickens around 4-6lbs. While no feather impressions or osteological correlates (quill knobs with Velociraptor) have been found, given the prevalence of feathers in dromaeosaurs, and its small size, it's basically a given that this tiny raptor had feathers.

Like all dromaeosaurs, it has an enlarged digit 1 claw however, whether it was used for dispatching prey is a subject of debate given it wasn't as recurved. Despite its small size, proportionally, the legs were longer than its northern relatives. Suggesting a more cursorial mode of locomotion. Even more intriguing is that this animal had what appeared to be a sub-arctometatarsal foot bone construction. An arctometatarsal is a condition present among Tyrannosaurs, Ornithomimids, and Troodontids. It's when the inner and outer metatarsal pinch the one in the center together. A feature like this assists animals in agility and likely has implications for how this animal moved.

A feature unique to Buitreraptor and its subfamily compared to other dromaeosaurs was its narrow and elongated skull. The skull was filled with teeth which were miniscule and lack the serrations of their northern relatives but are recurved, yet flat. A feature that will be discussed later.

Classification:

Buitreraptor is a member of the unenlagiinae. A subfamily of dromaeosaurs that have been found largely in South America. There is debate as to whether they were found in other regions in the southern hemisphere. With fragmentary fossils being found in Africa and Australia being attributed to them. Some even think that dromaeosaurs like Pyroraptor being theorized to be one, or even in North America with animals like Dakotaraptor being posited to be an unenlagiine (now believed to be untrue).

The type genus, Unenlagia itself was discovered in the 90s and identified as a dromaeosaur. In 1999, the legendary Argentinian paleontologist José Fernando Bonaparte described the subfamily as being distinctive to its northern kin as it had longer legs, less stocky build, and a differently shaped pubis, however, this was largely circumstantial. It wouldn't be until Buitreraptor was discovered that Bonaparte's theory was vindicated. With a pubis similar to Unenlagia, it was classified as an unenlagiine.

Buitreraptor helped shed light on these more bizarre South American paravians. Not only were these animals more lightly built, as previously stated, they had a sub-arctometatarsalian condition. Furthermore, the animals had a longer and more stiffened tail compared to animals like Velociraptor and Deinonychus. With animals like Buitreraptor and the giant Austroraptor having skull material discovered, it shows these animals had an elongated skull, even more so than Velociraptor and it had a narrow rostrum with lightly built, but recurved teeth. Finally, the foot bones were smaller and less robustly built compared to their northern relatives.

It's likely due to South America being isolated, dromaeosaurs became adapted to a different niche. Not becoming powerful ambush hunters but filling a reduced role in their ecosystems as many were small animals and lived in the shadow of larger predators like carcharodontosaurs and abelisaurs.

Implications of Unenlagiine behavior:

Dromaeosaurs as a whole have been described as being powerful ambush hunters. It's now believed that many northern dromaeosaurs ambushed their prey, pined them down with their claws and then picked at it while still alive with the victim dying of shock and organ failure. This is known as Raptor Prey Restraint. Despite being shown as fast predators, dromaeosaurs with their heavily built feet and leg construction likely made northern dromaeosaurs strong to avg. speed ambush predators, likely about as fast as an average runner around 15-22mph. Fast, but about as fast as a fit human.

Buitreraptor and its kin, the unenlagiines were very different. With their sub-arctometatarsalian condition, it implies these animals were more cursorial and agile. These animals could have been speedy predators designed to run down prey. They were probably adapted to be not only more agile, but with their longer limbs they were also faster perhaps reaching speeds equivalent to the fastest birds or non-avian dinosaurs. However, there was a trade-off with this agility.

For one the foot bones were lithe and not as robust as their northern kin, the hinges were not as powerful, and it suggests that these animals could not perform raptor prey restraint. The infamous sickle claw was not as recurved and perhaps couldn't have been used to puncture prey effectively. Moreover, with its longer head, teeth that lack serrations its likely they couldn't even kill larger prey. Why would such a narrow skull evolve among these dromaeosaurs?

Given its more agile nature and skull build, it's likely that Buitreraptor and its kin hunted small mammals, lizards, or animals they could have gotten down in one go. How they dispatched prey is unknown, they could have done a reduced form of RPR or, they could have done something different. Animals like the modern South American seriema kill small lizards and mammals by picking them up and then slamming it down to the ground. seriema are also fast runners and like most birds of prey, they have a sickle claw, but it is also reduced. Perhaps this could be a modern analogue to what unenlagiines were like.

Habitat:

Buitreraptor resided in the Candeleros Formation around 99-97,000,000 years ago. The environment would have been an arid mountainous environment similar to parts of modern Patagonia, but it would have been warmer, with rivers crisscrossing the environment. Conifers, cycad and horsetail would have been the prominent flora in the region.

Buitreraptor was a small animal in this ecosystem. It shared this environment with sauropods with animals like Limaysaurus, Rayososaurus being smaller sauropods 10-12 tons they were members of the rebbachisauridae, more derived diplodocids. The titans of the region were the titanosaurs with animals like Andesaurus roaming the fern prairies and forests weighing some 20-25 tons. However, in 2021, a giant titanosaur was discovered being the equivalent to Patagotitan and Argentinosaurus, perhaps weighing 50-70 tons. Even more recently was the tiny and primitive thyreophoran Jakapil similar to early Jurassic forms.

Trace fossils of iguanodonts of varying sizes have been found in the formation with some fragments also being found.

Alongside Buitreraptor were predators that thrived in this environment. The largest and most famous resident would undoubtedly be Giganotosaurus. The 40-45ft predator was the apex predator in the region hunting the sauropods and larger ornithopods in the region. Ekrixinatosaurus a large Abelisaur was also found here.

Buitreraptor scampered beneath these titans and hunted smaller animals. Among them would have been primitive lizards and rhynchocephalians (relatives of the Tuatara) like Tika and Priosphenodon. Furthermore, a small mammal called Cronopio was present here too. Hunting these lizards and mammals would have been easy pickings for this agile raptor. With its narrow jaws and recurved teeth, if it caught one of these mammals or lizards in its maw, it would have hooked them and Buitreraptor could have either swallowed it whole or behaved like seriemas and smashed them to the ground.

Competing directly with them and of similar size was the terrestrial crocodilian Araripesuchus. A sebecid that was around the size of a coyote and could've filled a similar niche to Buitreraptor. However, hatchlings could've been on the menu for this agile raptor as well.

Extinction:

Why Buitreraptor died off is unknown. Perhaps due to climate change and that caused this peculiar raptor to die off and be replaced by more derived members of unenlagiines some 97-96,000,000 years ago.

Despite the fact it's now gone, Buitreraptor offered an insight into the evolution and looks of this group of southern dromaeosaurs. With its description back in 2004, it solidified the distinctiveness of unenlagiines being a unique subfamily of dromaeosaurs. With a slew of adaptations designed to occupy a different niche than its northern relatives and become not a powerful ambush predator, but a lithe and swift pursuit hunter tackling smaller prey. Buitreraptor is another example of how diverse and unique prehistoric life is.
___________________________________________________________________________________________
Okay, this one was kind of easy, I decided to redo the old Buitreraptor profile I did about two years ago.

Mainly because it was done when I was still learning the basics of skinning and I also wanted to update the

I've seen a skeleton of Buitreraptor countless times at the Field Museum right next to Deinonychus. Buitreraptor is easily one of my favorite dromaeosaurs and I thought I'd write up a brief profile on this animal with a dueling pose between two individuals. A rather basic skin, but... eh... I still like this pose I gave both of these guys.

Will this be in PMP? Yes. I've made up my mind and we will be rescuing animals from Candeleros Patagonia. Will Buitreraptor be among them? You'll find out...

Original model and skin made by Ulquiorra and Lgcfm, modified by me:
Velociraptor (Lgcfm & Ulquiorra) | ZT2 Download Library Wiki | Fandom

Araripesuchus hatchling by DemonHunterZT2 thanks a ton for this Croc!