''Archicebus'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
fossil primates that lived in the early
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
forests (~55.8–54.8 million years ago) of what is now
Jingzhou
Jingzhou () is a prefecture-level city in southern Hubei province, China, located on the banks of the Yangtze River. Its total residential population was 5,231,180 based on the 2020 census, 1,068,291 of whom resided in the built-up (''or metro' ...
in the
Hubei
Hubei (; ; alternately Hupeh) is a landlocked province of the People's Republic of China, and is part of the Central China region. The name of the province means "north of the lake", referring to its position north of Dongting Lake. The prov ...
Province in central China, discovered in 2003.
The only known
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
, ''A. achilles'', was a small
primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...
, estimated to weigh about , and is the only known member of the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Archicebidae. When discovered, it was the oldest fossil
haplorhine
Haplorhini (), the haplorhines (Greek for "simple-nosed") or the "dry-nosed" primates, is a suborder of primates containing the tarsiers and the simians (Simiiformes or anthropoids), as sister of the Strepsirrhini ("moist-nosed"). The name is some ...
primate skeleton found,
appearing to be most 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 Southeast ...
s and the fossil
omomyid
Omomyidae is a group of early primates that radiated during the Eocene epoch between about (mya). Fossil omomyids are found in North America, Europe & Asia making it one of two groups of Eocene primates with a geographic distribution spanning h ...
s, although ''A. achilles'' is suggested to have been
diurnal, whereas tarsiers are
nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
. Resembling tarsiers and
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 Catarrhi ...
s (
monkey
Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as the simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes, which constitutes an incomple ...
s,
ape
Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its siste ...
s, and
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
s), it was a
haplorhine
Haplorhini (), the haplorhines (Greek for "simple-nosed") or the "dry-nosed" primates, is a suborder of primates containing the tarsiers and the simians (Simiiformes or anthropoids), as sister of the Strepsirrhini ("moist-nosed"). The name is some ...
primate, and it also may have resembled the last
common ancestor
Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. All living beings are in fact descendants of a unique ancestor commonly referred to as the last universal comm ...
of all haplorhines as well as the last common ancestor of all primates.
Its discovery further supports the hypothesis that primates originated in Asia, not in Africa.
Etymology
''Archicebus achilles'' was named for being the oldest-known primate skeleton () and for its distinguishing
calcaneus
In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock.
S ...
(heel bone).
The generic name, ''Archicebus'', was constructed from ''
arche
''Arche'' (; grc, ἀρχή; sometimes also transcribed as ''arkhé'') is a Greek word with primary senses "beginning", "origin" or "source of action" (: from the beginning, οr : the original argument), and later "first principle" or "element". ...
'' (ἀρχή), the
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
word for "beginning", and ''cebus'', the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
version of the Ancient Greek ''kêbos'' (κῆβος), which refers to a long-tailed monkey. The species name, ''achilles'', is a reference to
Achilles
In Greek mythology, Achilles ( ) or Achilleus ( grc-gre, Ἀχιλλεύς) was a hero of the Trojan War, the greatest of all the Greek warriors, and the central character of Homer's ''Iliad''. He was the son of the Nereid Thetis and Peleus, k ...
, the Greek hero of the
Trojan War
In Greek mythology, the Trojan War was waged against the city of Troy by the Achaeans (Greeks) after Paris of Troy took Helen from her husband Menelaus, king of Sparta. The war is one of the most important events in Greek mythology and has ...
from
Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...
.
Evolutionary history
''Archicebus achilles'' exhibits similarities with
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 Catarrhi ...
s with regard to the shape of its
calcaneus
In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock.
S ...
and the proportions of its
metatarsals
The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medi ...
, yet its skull, teeth, and
appendicular skeleton
The appendicular skeleton is the portion of the skeleton of vertebrates consisting of the bones that support the appendages. There are 126 bones. The appendicular skeleton includes the skeletal elements within the limbs, as well as supporting shou ...
resemble those of tarsiers. According to
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 ...
analysis, all of these traits taken together suggest it is the most
basal member of the
tarsiiform
Tarsiiformes are a group of primates that once ranged across Europe, northern Africa, Asia, and North America, but whose extant species are all found in the islands of Southeast Asia. Tarsiers (family Tarsiidae) are the only living members o ...
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
within the suborder
Haplorhini
Haplorhini (), the haplorhines (Greek for "simple-nosed") or the "dry-nosed" primates, is a suborder of primates containing the tarsiers and the simians (Simiiformes or anthropoids), as sister of the Strepsirrhini ("moist-nosed"). The name is some ...
. Considering its age, and since simians are a
sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and t ...
to tarsiiforms, ''A. achilles'' may closely resemble the common ancestor of haplorhines and possibly the last common ancestor of all primates.
Biogeography
The discovery of ''A. achilles'' adds further support to the hypothesis that primates originated in Asia, and not in Africa, with many
simians
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 Catarrhi ...
(a group of them) migrating to the latter continent thereafter.
Anatomy
![Reconstruction image of Archicebus](https://upload.wikimedia.org/wikipedia/commons/8/8a/Reconstruction_image_of_Archicebus.jpg)
''A. achilles'' is estimated to have weighed , making it comparable in size to today's smallest living primates,
mouse lemur
The mouse lemurs are nocturnal lemurs of the genus ''Microcebus''. Like all lemurs, mouse lemurs are native to Madagascar.
Mouse lemurs have a combined head, body and tail length of less than , making them the smallest primates (the smallest spe ...
s.
Range and ecology
''A. achilles'' lived in the forests of the warm
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
epoch, approximately 55.8 to 54.8 million years ago in a part of Asia near what now is
Jingzhou
Jingzhou () is a prefecture-level city in southern Hubei province, China, located on the banks of the Yangtze River. Its total residential population was 5,231,180 based on the 2020 census, 1,068,291 of whom resided in the built-up (''or metro' ...
, in the southern
Hubei
Hubei (; ; alternately Hupeh) is a landlocked province of the People's Republic of China, and is part of the Central China region. The name of the province means "north of the lake", referring to its position north of Dongting Lake. The prov ...
Province of China.
Judging from its large
canine teeth
In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened howeve ...
and sharp crests on its
premolar
The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...
s, ''A. achilles'' was
insectivorous
A robber fly eating a hoverfly
An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects.
The first vertebrate insectivores were ...
. Unlike tarsiers, however, its smaller eyes suggest it was
diurnal, a pattern previously suggested by other early haplorhines, such as ''
Teilhardina asiatica''. Its hind limbs suggest it did a lot of leaping; however, its hips, shoulders, and feet also suggest that it was not a
vertical clinger and leaper such as tarsiers and
galago
Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They ar ...
s are, but likely moved through the trees in a more generalized quadrupedal fashion by grasping tree limbs from above.
References
Literature cited
*
External links
Primate skeleton could give clues about human origins(
BBC News
BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broadca ...
)
*
{{Taxonbar, from=Q13421161, from2=Q13418266, from3=Q13421154
Eocene primates
Fossil taxa described in 2013
Mammals of China
Monotypic prehistoric primate genera
Prehistoric primate genera
Paleontology in Hubei
Tarsiers