Paleontologists have described a new species of terror bird, dubbed Llallawavis scagliai, which thrived on Earth 3.5 million years ago, based on some of the most complete fossil remains ever recovered for one of these creatures in Argentina.
The new specimen also revealed details of anatomy that rarely preserve in the fossil record, including the auditory region of the skull, voice box, complete trachea, bones for focussing the eye, and the complete palate, allowing an unprecedented understanding of the sensory capabilities of these extinct predatory birds.
This was the first time that the structures which indicate hearing sensitivity have been reconstructed for any terror bird, and they might help explain the evolution, behavior, and ecology of this group of fossil birds.
Terror birds, or phorusracids as they are known scientifically, were carnivorous flightless birds up to 3 meters (10 ft) in height with tall hooked beaks. These birds were the predominant predators during the Cenozoic Age in South America and certainly one of the most striking groups that lived during that time.
Dr. Claudia Tambussi, of CICTERRA, said that the discovery of this new species provided new insights for studying the anatomy and phylogeny of phorusrhacids and a better understanding of this group's diversification.
The new species stood 4 feet tall and lived in Argentina approximately 3.5 million years ago in the Pliocene Epoch, towards the end of the reign of the group.
Dr. Federico "Dino" Degrange, lead author of the study from the Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), CONICET and the Universidad Nacional de Cordoba, Argentina, said that the discovery of this species revealed that terror birds were more diverse in the Pliocene than previously thought, which would allow them to review the hypothesis about the decline and extinction of this fascinating group of birds.
The study is published in the Journal of Vertebrate Paleontology.