Researchers, including an evolutionary biologist at Johns Hopkins University, reported analyzing the fossil of a giant extinct meat-eating bird—which they say may have been the largest known member of its species—providing new information about animal life in northern South America millions of years ago. .

The evidence lies in the leg bone of the terror bird described in the new paper published November 4. Paleontology. The study was conducted by terror bird expert Federico J. Degrange and Siobhan Cookeassociate professor functional anatomy and evolution -most Johns Hopkins University School of Medicine. The bone, found in Colombia’s fossil-rich Tatacoa Desert at the northern tip of South America, is believed to be the northernmost evidence of the bird found so far in South America.

Caption: The end of the terror bird’s left tibia, a lower leg bone in birds equivalent to the human tibia or tibia, dates back to the Miocene epoch, about 12 million years ago.

Picture credit: Degrange et al.

The size of the bone also indicates that this terror bird may be the largest known member of the species described to date, approximately 5% to 20% larger than known. PhorusrhasidesCooke says. Previously discovered fossils indicate that terror bird species range in size from 10 to 9 feet in height.

“Terror birds lived on the ground, had limbs suitable for running, and mostly ate other animals,” says Cooke.

The bird’s leg bone was found nearly 20 years ago by Cesar Augusto Perdomo, curator of the Museo La Tormenta, but it was not recognized as a terror bird until 2023. In January 2024, researchers created a three-dimensional virtual model of the sample. A portable scanner from Johns Hopkins Medicine allows them to perform more detailed analysis.

The fossil, which is the end of the left tibiotarsus, a lower leg bone found in birds that is equivalent to the tibia or tibia in humans, dates back to the Miocene period, about 12 million years ago. Bone with deep pits unique to everyone’s legs PhorusrhasidesIt is also marked by possible teeth marks from an extinct caiman—PurussaurusIt’s a species thought to be up to 30 feet long, Cooke says.

“Given the size of crocodiles from 12 million years ago, we suspect the terror bird may have died as a result of its injuries,” he says.

Most terror bird fossils have been identified in the southern part of South America, including Argentina and Uruguay.

Scientists believe the (Tatacoa Desert) was once an environment filled with meandering rivers. This giant bird lived among primates, hoofed mammals, giant ground sloths, and glyptodonts, relatives of the car-sized armadillo.

The discovery of a Phorusrhacid fossil as far north as Colombia suggests that it was an important part of the predatory wildlife in the region. More importantly, this fossil helps researchers better understand the animals that lived in the region 12 million years ago. Now a desert, scientists believe the area was once an environment filled with winding rivers. This giant bird lived among primates, hoofed mammals, giant ground sloths, and glyptodonts, relatives of the car-sized armadillo. Today, the seriema, a long-legged bird native to South America that can reach up to 3 meters in length, is thought to be a modern relative of birds. phosphoric acid.

“This is a different kind of ecosystem from the period before the interconnection of South and North America than we see today or in other parts of the world,” Cooke says.

Cooke says the fossil, believed to be the first of its kind in the region, shows that the species was relatively rare among the animals there 12 million years ago.

“It is possible that there are fossils in existing collections that are not yet recognized as terror birds because the bones are less diagnostic than the lower leg bone we found,” he says.

For Cooke, this finding helps him imagine an environment that can no longer be found in nature.

“It would be a fascinating place to walk around and see these extinct animals,” he says.

In addition to Cooke and Perdomo, the study’s authors include first author Federico Javier Degrange of the Centro de Investigaciones en Ciencias de la Tierra; Luis G. Ortiz-Pabon from Universidad de Los Andes, Carrera, Bogotá, Colombia and Universidad Nacional de Colombia, Carrera, Bogotá; Jonathan Pelegrin from Universidad del Valle, Colombia and Universidad Santiago de Cali, Colombia; Rodolfo Salas-Gismondi from Universidad Nacional Mayor de San Marcos, Avenida Arenales, Peru; and Andrés Link from Universidad de Los Andes, Carrera Bogota, Colombia.