Одоогоос 83 сая жилийн тэртээ амьдарч байсан мегарапторид бүлгийн махчин үлэг гүрвэлийн үлдэгдлийг Аргентины хойд хэсгээс илрүүлжээ.
Аргентины Патагоны нутгаас олдсон бүрэн бус ясан дээр үндэслэн Rinconraptor pipoae хэмээх үлэг гүрвэлийн шинэ төрөл зүйлийг палеонтологчид тодорхойллоо. Энэхүү амьтан нь Цэрдийн галавын сүүлч үед буюу 83 сая жилийн өмнө амьдарч байсан бөгөөд дунд болон том биетэй, нарийн хойд мөч, хүчтэй махир шүд, гартаа том хумстай Megaraptoridae овогт хамаардаг байна. CONICET-ийн палеонтологч Ариэль Эрнан Мендез болон түүний багийнхан уг олдвор нь мегарапторид үлэг гүрвэлийн хувьслын холбоо хамаарлыг тодруулахад чухал ач холбогдолтой гэж үзэж байна.
Судлаачдын тооцоолсноор Rinconraptor pipoae нь ойролцоогоор 7 метр урттай байсан бөгөөд сүүл нь 40-45 үеэс бүрддэг байсан нь Тираннозавртай төстэй шинж юм. Олдворыг Ринкон де лос Саусес хотоос баруун өмнө зүгт 50 км-т орших Серро Оверо дахь Бахо де ла Карпа тогтоцоос илрүүлжээ. Малтлагаар сүүлний 10 нугалам, аарцагны ясны хэсэг, бугалга болон шилбэний ясны үлдэгдлийг ойролцоогоор 4 ам дөрвөлжин метр талбайгаас олсон байна.
Тухайн бүс нутагт хийсэн судалгаагаар мегарапторидууд нь абелизаурид зэрэг бусад том махчин үлэг гүрвэлүүдтэй зэрэгцэн амьдарч байсан нь тогтоогджээ. Эрдэмтдийн тайлбарлаж буйгаар, эдгээр махчин амьтад нөөц баялаг, хоол тэжээлийн төлөө өрсөлдөхгүйн тулд экологийн өөр өөр орон зайг эзлэн зэрэгцэн амьдарч байсан байх магадлалтай. Энэхүү бүс нутаг нь титанозавр болон бусад олон төрлийн үлэг гүрвэлүүд амьдарч байсан биологийн төрөл зүйл ихтэй экосистем байсныг олдворууд гэрчилж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Paleontologists have identified a new genus and species of megaraptorid dinosaur from an incomplete skeleton unearthed in northern Patagonia, Argentina. Named Rinconraptor pipoae, the animal roamed the planet some 83 million years ago, during the Late Cretaceous.
The newly described species belongs to the Megaraptoridae, a group of medium- to large-sized theropods known for slender hind limbs, strongly curved teeth and large claws on their hands. The family was recognized a decade ago.
The find matters because the group’s fossil record is thin. According to CONICET paleontologist Ariel Hernán Méndez and his colleagues, that record remains scarce and fragmentary, which is why the phylogenetic affinities of the group have been debated among specialists.
What the Group Looks Like
Megaraptorids are defined by a handful of unusual traits. As reported by Méndez and his colleagues, these include strongly curved teeth with an 8-shaped outline, elongated and slender hindlimb bones, highly pneumatic cranial and vertebral elements, and large trenchant manual claws. From South America to Asia and Australia, megaraptorans left behind fossils that reveal just how widespread they were.
Rinconraptor pipoae itself was about 7 m (23 feet) long, an estimate the researchers reached by comparing its vertebrae with those of better-known relatives. They also calculate that it had more than 40 to 45 tail segments, a pattern similar to that of Tyrannosaurus.
The Fossils and Where They Lay
The remains were found at Cerro Overo, about 50 km (30 miles) southwest of the city of Rincón de los Sauces. The specimens come from the Bajo de la Carpa Formation, part of the Río Colorado Subgroup within the Neuquén Group, in the Upper Cretaceous of the Neuquén Basin. The paleontologists say:
“Throughout the basin, this formation records a variety of paleoenvironments influenced by aeolian and fluvial depositional systems.”
The main fossil find wasn’t particularly large. It included 10 tail vertebrae, part of a bone from beneath the tail, the lower end of a left upper-arm bone, and the upper end of a right shinbone. The shinbone was still stuck in the rock, while the other bones were scattered across a small patch of ground measuring about 4 square meters (43 square feet).
The researchers also found several other megaraptorid bones nearby, though they couldn’t link them to a specific species. Based on their estimates, these dinosaurs measured between 6 and 8.5 meters (20 to 28 feet) long.
Sharing the Land With Other Apex Predators
One of the most interesting findings is that megaraptorids weren’t the only large predators around. As reported by the study, Palaeontologia Electronica, medium- and large-sized megaraptorids lived in the Cerro Overo-La Invernada area at the same time as abelisaurids of similar size, during the Santonian period. With two groups of top predators sharing the same territory, they may have competed for food and other resources.
And yet the picture may not be so simple. The theropod fossil record in the area could indicate some partitioning of the ecological niche occupied by both groups of carnivorous dinosaurs, to avoid direct competition and allow coexistence.
The area, the authors add, represents an ecosystem with high faunal biodiversity, including titanosaur sauropods, as well as elasmarian and indeterminate ornithopods, among other species.
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