For the first time, footprints made by an extinct terror bird (family Phorusrhacidae) have been identified by paleontologists.
Terror birds belong to Phorusrhacidae, an extinct family of large, carnivorous, flightless birds.
These birds had a very large body mass, up to 70 kg, and were between 0.9-2 m (3-6.6 feet) in height.
They were the predominant predators during the Cenozoic in South America, but they are also from the Plio-Pleistocene of North America and the Eocene of Africa.
Phorusrhacidae contains almost 20 species in 14 genera and 5 subfamilies (Brontornithinae, Mesembriornithinae, Patagornithinae, Phorusrhacinae, and Psilopterinae).
Their closest living relatives are believed to be seriemas, the sole living members of the family Cariamidae.
“Terror birds comprise the most outstanding group of South American Cenozoic avifauna, and have been considered as dominant predators in Cenozoic ecosystems,” said Universidad Nacional de La Pampa paleontologist Ricardo Melchor and his colleagues.
“Their terrestrial habits have been well established based on the reduction of their forelimbs and high body mass.”
“One of the pillars for the hypothesis of a predatory mode of life for phorusrhacids is based on the morphology of their hind limbs, which seem to be suitable for pursuing prey.”
“Comparison of the hindlimb of phorusrhacids with those of extant groups suggests that Mesembriornithinae and Patagornithinae were likely cursorial birds, but members of the Psilopterinae were likely walkers and waders.”
The excellently-preserved footprints of a medium- to large-sized terror bird, probably belonging to the Mesembriornithinae subfamily, were recently found in coastal outcrops of the Río Negro Formation at the San Matías Gulf (Atlantic coast of Argentina).
“These are the first and only known fossil footprints assigned to this group of birds,” the paleontologists said.
The footprints date back nearly 8 million years (Late Miocene epoch) and…
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