Azibius is an extinct genus of fossil primate from the late early or early middle Eocene from the Glib Zegdou Formation in the Gour Lazib area of Algeria. They are thought to be related to the living toothcombed primates, the lemurs and lorisoids (known as strepsirrhines), although paleoanthropologists such as Marc Godinot have argued that they may be early simians (monkeys and apes). Originally described as a type of plesiadapiform (an extinct group of arboreal mammals considered to be a sister group to the primate clade), its fragmentary remains have been interpreted as a hyopsodontid (a type of extinct condylarth), an adapid (an extinct type of adapiform primate from Europe), and a macroscelidid (elephant shrews). Less fragmentary remains discovered between 2003 and 2009 demonstrated a close relationship between Azibius and Algeripithecus, a fossil primate once thought to be the oldest known simian. Descriptions of the talus (ankle bone) in 2011 have helped to strengthen support for the strepsirrhine status of Azibius and Algeripithecus, which would indicate that the evolutionary history of lemurs and their kin is rooted in Africa. Azibius trerki is the only named species, although a few teeth and a talus (ankle bone) of a larger, unnamed species (cf. Azibius sp.) have also been found. A. trerki is estimated to have weighed , while cf. Azibius sp. was larger, weighing approximately . Based on the fragmentary fossils, both are thought to have been nocturnal and agile arboreal quadrupeds. Evolutionary history and taxonomy For years following its discovery, Azibius was difficult to classify. Originally described by Jean Sudre in 1975 as a possible 'paromomyiform' (a type of plesiadapiform), A. trerki was also interpreted as a hyopsodontid by paleoanthropologist Frederick S. Szalay that same year. The following year, paleoanthropologist Philip D. Gingerich reclassified it as an adapid. Throughout the 1990s and 2000s, debates over its classification continued, with some researchers suggesting it might be related to macroscelidids (elephant shrews), while others supported initial interpretations as adapids or plesiadapiforms (particularly carpolestids). In 2006, paleoanthropologist Marc Godinot favored a relationship between Azibius and simians, but tentatively suggested Azibius may be more closely related to toothcombed primates, which include all extant strepsirrhines. This latter view has gained increasing support with the reclassification of Algeripithecus (once considered a basal simian) as a closely related azibiid. The mandible of Algeripithecus indicates it had an inclined canine tooth, similar to that found in toothcombed primates. Although