Produced by the Population Genetics and Evolution class, Furman University

The Paleogene: Phorusrhacids
Phorusrhacids (Terror Birds) were a group of large, flightless, carnivorous birds that dominated South America (Wikipedia 2010). The average height of the predators varied from 1-3 meters (Wikipedia 2010; National Geographic 2005). The smallest terror bird was Psilopterus lemoinei, that was approximately the size of a harpy eagle (1 m tall). The largest (Brontornis burmeisteri) stood approximately 10 ft and weighed over a half ton (NationalGeographic 2005). Because their beaks resemble those of modern predatory eagles and scavenging vultures, phorusrhacids are believed to have been carnivorous birds (NationalGeographic 2005). Larger species could easily crush the skulls and break bones of its prey using its powerful beak and legs (Wikipedia 2010; NationalGeographic 2005). These birds evolved in isolation until South and North America collided (NationalGeographic 2005). As a result of the central american land bridge and faunal exchange between the contintents, some recent species like Titanis walleri has been found in areas as far north as Texas and Florida (Wikipedia 2010; ScienceBlog 2010). However, this collision is also considered to be the cause of the extinction of the Phorusrhacids. The collision allowed North American predators (Jaguars and Saber-toothed cats) may have out-competed the remaining terror birds to extinction (NationalGerographic 2005). Two species of extant South American birds, Seriemas, are 80 cm-tall and are considered to be their closest modern relatives.

Page by Matt Medlin
Phorusrhacid. Photo from: photobucket.com

Wikipedia. 2010. Phorusrhacidae. Wikipedia. Accessed April 18, 2010.

Naish D. 2008. Raven, the claw-handed bird, last of the phosusrhacid. ScienceBlogs.com. Accessed April 18, 2010.

Pickrell J. 2005. Terror Birds: Predators with a Kung Fu Kick?. NationalGeographic.com. Accessed April 18, 2010.