Fossil of big terror chook presents new details about wildlife in South America 12 million years in the past

The proof lies within the leg bone of the phobia chook described in new paper printed Nov. 4 in Palaeontology. The examine was led by Federico J. Degrange, a terror chook specialist, and included Siobhán Cooke, Ph.D., affiliate professor of practical anatomy and evolution on the Johns Hopkins College College of Medication. The bone, discovered within the fossil-rich Tatacoa Desert in Colombia, which sits on the northern tip of South America, is believed to be the northernmost proof of the chook in South America up to now.

The dimensions of the bone additionally signifies that this terror chook will be the largest recognized member of the species recognized so far, roughly 5%-20% bigger than recognized Phorusrhacids, Cooke says. Beforehand found fossils point out that terror chook species ranged in dimension from 3 ft to 9 ft tall.

“Terror birds lived on the bottom, had limbs tailored for operating, and principally ate different animals,” Cooke says.

The chook’s leg bone was discovered by Cesar Augusto Perdomo, curator of the Museo La Tormenta, almost 20 years in the past, however was not acknowledged as a terror chook till 2023. In January 2024, researchers created a three-dimensional digital mannequin of the specimen utilizing a transportable scanner from Johns Hopkins Medication, permitting them to research it additional.

The fossil, the tip of a left tibiotarsus, a decrease leg bone in birds equal to that of a human tibia or shin bone, dates again to the Miocene epoch round 12 million years in the past. The bone, with deep pits distinctive to the legs of all Phorusrhacids, can also be marked with possible tooth marks of an extinct caiman — Purussaurus — a species that’s thought to have been as much as 30 ft lengthy, Cooke says.

“We suspect that the phobia chook would have died on account of its accidents given the dimensions of crocodilians 12 million years in the past,” she says.

Most terror chook fossils have been recognized within the southern a part of South America, together with Argentina and Uruguay.

The Phorusrhacid fossil discovery as far north as Colombia means that it was an necessary a part of predatory wildlife within the area. Importantly, this fossil helps the researchers higher perceive the animals dwelling within the area 12 million years in the past. Now a desert, scientists imagine this area was as soon as an atmosphere filled with meandering rivers. This big chook lived amongst primates, hoofed mammals, big floor sloths and armadillo family members, glyptodonts, that had been the dimensions of automobiles. Right this moment, the seriema, a long-legged chook native to South America that stands as much as 3-feet-tall, is regarded as a contemporary relative of Phorusrhacid.

“It is a completely different form of ecosystem than we see in the present day or in different components of the world throughout a interval earlier than South and North America had been linked,” Cooke says

Believed to be the primary of its type from the positioning, the fossil signifies that the species would have been comparatively unusual among the many animals there 12 million years in the past, Cooke says.

“It is attainable there are fossils in current collections that have not been acknowledged but as terror birds as a result of the bones are much less diagnostic than the decrease leg bone we discovered,” she says.

For Cooke, the discovering helps her think about an atmosphere one can not discover in nature.

“It will have been a captivating place to stroll round and see all of those now extinct animals,” she says.

Along with Cooke and Perdomo, the examine’s authors embody first writer Federico Javier Degrange of Centro de Investigaciones en Ciencias de la Tierra; Luis G. Ortiz-Pabon of Universidad de Los Andes, Carrera, Bogotá, Colombia and Universidad Nacional de Colombia, Carrera, Bogotá; Jonathan Pelegrin of Universidad del Valle, Colombia, and Universidad Santiago de Cali, Colombia; Rodolfo Salas-Gismondi of Universidad Nacional Mayor de San Marcos, Avenida Arenales, Perú; and Andrés Hyperlink of Universidad de Los Andes, Carrera Bogotá, Colombia.