| Archicebus | |
|---|---|
 | |
| Holotype | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Primates |
| Suborder: | Haplorhini |
| Infraorder: | Tarsiiformes |
| Family: | †Archicebidae Niet al.2013 |
| Genus: | †Archicebus Niet al. 2013 |
| Species: | †A. achilles |
| Binomial name | |
| †Archicebus achilles Niet al. 2013 | |
Archicebus is agenus offossil primates that lived in the earlyEocene forests (~55.8–54.8 million years ago) of what is nowJingzhou in theHubei Province in central China, discovered in 2003.[1][2] The only knownspecies,A. achilles, was a smallprimate, estimated to weigh about 20–30 grams (0.7–1.1 oz), and is the only known member of thefamilyArchicebidae. When discovered, it was the oldest fossilhaplorhine primate skeleton found,[3][4] appearing to be most closely related totarsiers and the fossilomomyids, althoughA. achilles is suggested to have beendiurnal, whereas tarsiers arenocturnal. Resembling tarsiers andsimians (monkeys andapes), it was ahaplorhine primate, and it also may have resembled the lastcommon ancestor of all haplorhines.
Archicebus achilles was named for being the oldest-known primate skeleton (as of 2013[update]) and for its distinguishingcalcaneus (heel bone).[5] The generic name,Archicebus, was constructed fromarche (ἀρχή), theAncient Greek word for "beginning", andcebus, theLatin version of the Ancient Greekkêbos (κῆβος), which refers to a long-tailed monkey. The species name,achilles, is a reference toAchilles, the Greek hero of theTrojan War fromGreek mythology.[6]
Archicebus achilles exhibits similarities withsimians with regard to the shape of itscalcaneus and the proportions of itsmetatarsals, yet its skull, teeth, andappendicular skeleton resemble those of tarsiers. According tophylogenetic analysis, all of these traits taken together suggest it is the mostbasal member of thetarsiiformclade within the suborderHaplorhini. Considering its age, and since simians are asister group to tarsiiforms,A. achilles may closely resemble the common ancestor of haplorhines and possibly the last common ancestor of all primates.[7]
| Phylogeny of primates[8] |
| According to Niet al. 2013,Archicebus is abasal member of theclade containing tarsiers, making it a close relative of monkeys and apes. |
The discovery ofA. achilles adds further support to the hypothesis that primates originated in Asia, and not in Africa, with manysimians (a group of them) migrating to the latter continent thereafter.[3]
A. achilles is estimated to have weighed 20 to 30 g (0.7 to 1.1 oz), making it comparable in size to today's smallest living primates,mouse lemurs.[8]
A. achilles lived in the forests of the warmEocene epoch, approximately 55.8 to 54.8 million years ago in a part of Asia near what now isJingzhou, in the southernHubei Province of China.[2][3][6]
Judging from its largecanine teeth and sharp crests on itspremolars,A. achilles wasinsectivorous. Unlike tarsiers, however, its smaller eyes suggest it wasdiurnal, a pattern previously suggested by other early haplorhines, such asTeilhardina asiatica. Its hind limbs suggest it did a lot of leaping; however, its hips, shoulders, and feet also suggest that it was not avertical clinger and leaper such as tarsiers andgalagos are, but likely moved through the trees in a more generalized quadrupedal fashion by grasping tree limbs from above.[7]
