#Archovember Day 19 - Kelenken guillermoi

The Phorusrhacids, commonly known as “terror birds” were the last dinosaurian apex predators to hunt on land. The largest known phorusrhacid, Kelenken guillermoi, lived in the Middle Miocene of Argentina. It is known only from a skull (though it is one of the most complete large phorusrhacid skulls) and a leg and toe bone, so the rest of its anatomy must be inferred from other phorusrhacids. The skull, the largest of any known bird, is 716 mm (2.3 ft) long, allowing us to estimate Kelenken’s height at around 3 m (9.8 ft) tall. Kelenken would have lived in an open, grassland environment. Its long, slender tarsometatarsus suggests that it was a fast runner, likely adapted for chasing down small animals like rodents, marsupials, and lizards. While large, its skull was relatively weak, so it would have had difficulty gripping onto and subduing large, struggling prey. Instead, it likely preyed on animals it could swallow whole and/or, if targetting larger prey, used repetitive, targeted pecks with its beak. It could have also used its feet to restrain prey. While only Kelenken’s phalanx toe bone has been found, other large phorusrhacids (as well as their living relatives, the seriemas) have a “sickle claw” on their second digits, similar to dromaeosaurs. These claws could have also been used to restrain prey, or to kick out and strike.

Gone, but not forgotten (D)

Extinct or near extinct birds only here. There aren't enough to have this be more than one bracket, so there will definitely be an info-post for the winner.

Oh this is a great one! (and maniraptorans is right, don't worry!)

Might I recommend this excellent video by Moth Light Media on the subject?

• Pliocene Predators •