''Altiatlasius'' ("

High Atlas High Atlas, also called the Grand Atlas ( ar, الأطلس الكبير, Al-Aṭlas al-Kabīr; french: Haut Atlas; shi, ⴰⴷⵔⴰⵔ ⵏ ⴷⵔⵏ ''Adrar n Dern''), is a mountain range in central Morocco, North Africa, the highest part of t ...

" from Latin altus, "high" + Atlas, "Atlas") is an extinct genus of mammal, which may have been the oldest known

primate Primates are a diverse order (biology), order of mammals. They are divided into the Strepsirrhini, strepsirrhines, which include the lemurs, galagos, and lorisids, and the Haplorhini, haplorhines, which include the Tarsiiformes, tarsiers and ...

, dating to the Late

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...

(c.57 ma) from

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria ...

. The only species, ''Altiatlasius koulchii'', was described in 1990. Its true taxonomic position remains controversial. It has also been suggested that it should be classified as a plesiadapiform (an extinct group of arboreal mammal thought to be ancestral to primates) or that it should be recognized as a euprimate, either as an omomyid (a branch of fossil primates thought to be closely related to

tarsier Tarsiers ( ) are haplorhine primates of the family Tarsiidae, which is itself the lone extant family within the infraorder Tarsiiformes. Although the group was once more widespread, all of its species living today are found in Maritime Southe ...

s), an early tarsiiform, or the oldest

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushr ...

simian The simians, anthropoids, or higher primates are an infraorder (Simiiformes ) of primates containing all animals traditionally called monkeys and apes. More precisely, they consist of the parvorders New World monkeys (Platyrrhini) and Cat ...

(monkeys and apes).

Evolutionary history and taxonomy

''Altiatlasius koulchii'', potentially the oldest known euprimate, is known only from ten isolated upper and lower

molars The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...

and a fragment of a

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bon ...

. These fossils date to the Late

, approximately 57 million years ago, and come from the Jbel Guersif Formation in the Ouarzazate Basin of

. First described in 1990 by Sigé ''et al.'', ''Altiatlasius'' was originally proposed to be an omomyid, possibly close to the split with

s (monkeys and apes). It has also been classified in the family Toliapinidae, a type of plesiadapiform found in Europe. Other classifications assume they are

euprimates, eosimiid-like simians, or an early tarsiiform. Many authorities consider ''Altiatlasius'' to be the oldest stem simian. Godinot (1994) and Bajpai ''et al''. (2008) both support the view that it is an early anthropoid (simian). Together with the Early to Middle

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

fossil primate '' Algeripithecus'' (originally thought to be the oldest

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...

simian) from

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , religi ...

, ''Altiatlasius'' helped strengthen the argument for an African origin of simian primates. However, when additional fossil remains of ''Algeripithecus'' were found, it was shown to be a

strepsirrhine Strepsirrhini or Strepsirhini (; ) is a Order (biology), suborder of primates that includes the Lemuriformes, lemuriform primates, which consist of the lemurs of Fauna of Madagascar, Madagascar, galagos ("bushbabies") and pottos from Fauna of A ...

primate instead of a haplorhine, placing it with the azibiids, a group thought to be most closely related to lemuriforms (living

lemur Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are wet-nosed primates of the superfamily Lemuroidea (), divided into 8 families and consisting of 15 genera and around 100 existing species. They are endemic to the island of Madaga ...

s and lorisoids). Because ''Algeripithecus'' was radically reclassified with the discovery of more fossils, equally fragmentary remains of ''Altiatlasius'' leave its

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

affinities questionable. Also, the 20 million year gap in the fossil record between ''Altiatlasius'' and the first parapithecoids raises questions about the validity of the African origins hypothesis for simians.

Notes

References

Literature cited

* * * * * * {{Taxonbar, from=Q627032 Paleocene mammals Prehistoric primate genera Paleocene mammals of Africa Fossil taxa described in 1990