Stirtonia tatacoensis

Stirtonia tatacoensis is an extinct New World monkey of the Middle Miocene (Laventan, about 13.8 to 11.8 million years ago) from the Honda Group of the Tatacoa Desert at La Venta, Colombia, and the type species of Stirtonia. Its name comes from the Tatacoa desert, and the genus honours the paleontologist Ruben Arthur Stirton, who first found the fossils; Homunculus tatacoensis and Kondous laventicus are synonyms. It is known from teeth and a lower jaw, with an estimated body mass of about 5.5 kilograms, and these remains closely resemble those of the living howler monkeys. The genus is classified in the Alouattini as an ancestor of Alouatta. La Venta was probably seasonally dry forest in contact with the Amazon and Orinoco basins, and other fossil primates were found at the same level.