A discovery in the field of paleontology has revealed the diversity of theropod dinosaurs during the Late Cretaceous Epoch. An international team of researchers led by National Geographic Explorer Diego Pol unearthed a new species of carnivorous dinosaur in Argentina. This newly discovered species is named Koleken inakayali, provides insights into the evolution of abelisaurid theropods in Patagonia just before the mass extinction event that wiped out the dinosaurs.

Koleken Inakayali: New Dinosaur Species with Tiny Arms Discovered in Patagonia

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Koleken inakayali is distinguished by its small arms, a characteristic trait of the abelisaurid family. Unlike its famous relative Carnotaurus, Koleken has unique skull features and lacks the frontal horns. Koleken is smaller than Carnotaurus.

The partial skeleton of Koleken inakayali was unearthed from the La Colonia Formation, a site known for its Late Cretaceous deposits. The fossil collection includes:

  • Several skull bones
  • Almost all backbones
  • A complete hip
  • Several tail bones
  • Two nearly complete legs

The name Koleken inakayali is derived from the language of the Tehuelche people of Central Patagonia with “Inakayal” honoring one of their last leaders.

Koleken inakayali shares some similarities with Carnotaurus, another abelisaurid popularized by films such as Jurassic World. Both dinosaurs were predators with small arms

Koleken is notably smaller. Koleken lacks the massive frontal horns. Carnotaurus is thought to have used its tiny arms and specially adapted shoulder girdle for mating displays. The function of Koleken’s tiny arms remains unknown.

Diego Pol, a National Geographic Explorer and leader of the study addressed the importance of this discovery. He stated, “This finding sheds light on the diversity of abelisaurid theropods in Patagonia right before the mass extinction event. Our study also analyzes the evolution of abelisaurids and their relatives through time, and identifies pulses of accelerated rates of skull evolution in the Early Cretaceous.”

The discovery of Koleken inakayali is part of a larger project funded by the National Geographic Society planning to explore the end of the “age of dinosaurs” in Patagonia.

This project focuses on the last 15 million years of the Cretaceous Period, a time frame that has been less studied in the Southern Hemisphere.

The detailed research on Koleken inakayali has been published in the journal Cladistics. The study provides an analysis of the fossil remains and their implications for understanding the evolution of abelisaurids in the Late Cretaceous Epoch.

This discovery was made possible through the collaborative efforts of paleontologists from Argentina, the United States, and Hong Kong.

The research team included scientists such as Fernando Novas, Mattia Antonio Baiano, David Černý, Ignacio Cerda, and Michael Pittman.

The project receives support from the National Geographic Society. Ian Miller, the Society’s Chief Science and Innovation Officer, stated, “The discovery of Koleken inakayali significantly furthers our collective scientific understanding of the dinosaur era. The addition of Koleken inakayali to the La Colonia Formation fauna continues to demonstrate that the Formation is amongst the most important end-Cretaceous dinosaur-bearing rock units in the world.”

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The discovery of Koleken inakayali adds to the growing evidence of the abelisaurid population in Patagonia during the Late Cretaceous.

This region appears to have been a hotspot for these carnivorous dinosaurs, as indicated by the findings of other species such as Titanomachya gimenezi.

The fossils were unearthed from the La Colonia Formation in central Patagonia’s Chubut Province, Argentina.

The La Colonia Formation is renowned for its rich deposits of dinosaur fossils and other prehistoric creatures.

The discovery was made by an international team including researchers from Argentina, the United States, and Hong Kong and was led by Diego Pol.

This new species lived around 70 million years ago during the Late Cretaceous Epoch. Koleken inakayali is part of the abelisaurid family, a group of theropod dinosaurs.

The species is named in honor of the Tehuelche people and their leader, Inakayal. The name Koleken inakayali refers to the claystone where the fossils were found and pays tribute to the indigenous heritage.

The well-preserved partial skeleton includes multiple head bones, an almost complete sequence of backbones, a full hip, several tail bones, and nearly complete legs. The skeleton has various unique skull features that differentiate it from other known abelisaurids.

Koleken inakayali is closely related to Carnotaurus sastrei, famously known as the “meat bull.” Unlike Carnotaurus, which has iconic frontal horns, Koleken lacks these horns. This distinction highlights the diversity within the abelisaurid family.

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The study analyzes the evolution of abelisaurids and their relatives through time, identifying periods of accelerated skull evolution in the Early Cretaceous.

The findings expand our understanding of abelisaurids in the Cretaceous Period and demonstrate their diversity was greater than previously understood.

Koleken coexisted with Titanomachya gimenezi, a large, cow-sized titanosaur. The fossils of Titanomachya were discovered in the same formation just a month prior to Koleken.

The La Colonia Formation has yielded extraordinary remains of several prehistoric animals including predatory dinosaurs, plesiosaurs, and turtles.

Diego Pol’s extensive research focuses on discovering and studying dinosaurs and vertebrates that inhabited Patagonia during the last 15 million years of the Cretaceous Period. The findings have been published in the scientific journal Cladistics.

Koleken inakayali belongs to the abelisaurid family prevalent in the southern hemisphere supercontinent Gondwana which included present-day South America, Africa, India, Madagascar, Australia, and Antarctica.

The mass extinction that wiped out the dinosaurs occurred approximately 66 million years ago. This discovery provides insights into the diversity of life forms just before this event.

The fossilized remains were well-preserved transported by river currents to the location where they were buried shortly after death. The bones were carefully prepared and studied at the Egidio Feruglio Paleontological Museum.

This discovery is part of a multidisciplinary project, “The End of the Dinosaur Age in Patagonia,” supported by the National Geographic Society.

More than 70 researchers and scholarship holders from various institutions participated. The project’s plan is to decode extinction patterns at the end of the Cretaceous in South America and compare them to other global regions.

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