Azibiidae

Azibiidae
Temporal range: 52–46 Ma Early to Middle Eocene
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Strepsirrhini
Infraorder: incertae sedis
Family: Azibiidae
Gingerich, 1976
Genera

Azibiidae is an extinct family 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). It includes the genera Azibius and Algeripithecus, the latter of which was originally considered the oldest known simian, not a strepsirrhine.

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. 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. Likewise, if azibiids are simians, it would support the hypothesis that simians originated in Africa instead of Asia.

Azibiids were small-bodied primates, with Algeripithecus minutus weighing between 65 and 85 g (2.3 and 3.0 oz), Azibius trerki weighing approximately 115 and 160 g (4.1 and 5.6 oz), and an unnamed species of Azibius being notably larger, weighing an estimated 630 to 920 g (22 to 32 oz).