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 ...

australopithecine Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally ''Australopithecus'' (cladistically including the genera ''Homo'', '' Paranthropus'', and ''Kenyanthropus''), and it typically includ ...

Afar Region The Afar Region (; aa, Qafar Rakaakayak; am, አፋር ክልል), formerly known as Region 2, is a regional state in northeastern Ethiopia and the homeland of the Afar people. Its capital is the planned city of Semera, which lies on the pave ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58A. afarensis''. ''A. deyiremeda'' is distinguished by its forward-facing cheek bones and small cheek teeth compared to those of other early

hominin The Hominini form a taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera ''Homo'' (humans) and '' Pan'' (chimpanzees and bonobos) and in standard usage excludes the genus ''Gorilla'' (gorillas). The ...

s. It is unclear if a partial foot specimen exhibiting a dextrous big toe (a characteristic unknown in any australopith) can be assigned to ''A. deyiremeda''. ''A. deyiremeda'' lived in a mosaic environment featuring both open grasslands and lake- or riverside forests, and anthropologist Fred Spoor suggests it may have been involved in the Kenyan

Lomekwi Lomekwi 3 is the name of an archaeological site in Kenya where ancient stone tools have been discovered dating to 3.3 million years ago, which make them the oldest ever found. Discovery In July 2011, a team of archeologists led by Sonia Harma ...

stone-tool

industry Industry may refer to: Economics * Industry (economics), a generally categorized branch of economic activity * Industry (manufacturing), a specific branch of economic activity, typically in factories with machinery * The wider industrial sector ...

typically assigned to ''

Kenyanthropus ''Kenyanthropus'' is a hominin genus identified from the Lomekwi site by Lake Turkana, Kenya, dated to 3.3 to 3.2 million years ago during the Middle Pliocene. It contains one species, ''K. platyops'', but may also include the 2 million year ...

''. ''A. deyiremeda'' coexisted with ''A. afarensis'', and they may have exhibited

niche partitioning In ecology, niche differentiation (also known as niche segregation, niche separation and niche partitioning) refers to the process by which competing species use the environment differently in a way that helps them to coexist. The competitive exclu ...

to avoid competing with each other for the same resources, such as by relying on different fallback foods during leaner times.

Taxonomy

''Australopithecus deyiremeda'' was first proposed in 2015 by Ethiopian palaeoanthropologist

Yohannes Haile-Selassie Yohannes Haile-Selassie Ambaye (born 23 February 1961) is an Ethiopian paleoanthropologist. An authority on pre-''Homo sapiens'' hominids, he particularly focuses his attention on the East African Rift and Middle Awash valleys.Mangels, John (200 ...

and colleagues based on jawbone fossils from the Burtele and Waytaleyta areas of Woranso–Mille,

Afar Region The Afar Region (; aa, Qafar Rakaakayak; am, አፋር ክልል), formerly known as Region 2, is a regional state in northeastern Ethiopia and the homeland of the Afar people. Its capital is the planned city of Semera, which lies on the pave ...

, Ethiopia. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

specimen, a young adult left

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

with all teeth except the first

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

and third molar BRT-VP-3/1, was discovered on 4 March 2011 by local resident Mohammed Barao. The paratype specimens are a complete adult body of the mandible with all incisors BRT-VP-3/14, and an adult right toothless jawbone WYT-VP-2/10, which were discovered by Ethiopian fossil hunter Ato Alemayehu Asfaw . A right maxilla fragment with the fourth premolar BRT-VP-3/37 was found east of BRT-VP-3/14, and it is unclear if these belonged to the same individual. The sediments were radiometrically dated to 3.5–3.3 million years ago, the Middle Pliocene. The describers believed the remains were distinct enough from the contemporary and well-known '' A. afarensis'' to warrant species distinction, and ''A. deyiremeda'' is counted among a growing diversity of

Late Pliocene Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

australopithecine Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally ''Australopithecus'' (cladistically including the genera ''Homo'', '' Paranthropus'', and ''Kenyanthropus''), and it typically includ ...

s alongside ''A. afarensis'', '' A. bahrelghazali'' and ''

Kenyanthropus platyops ''Kenyanthropus'' is a hominin genus identified from the Lomekwi site by Lake Turkana, Kenya, dated to 3.3 to 3.2 million years ago during the Middle Pliocene. It contains one species, ''K. platyops'', but may also include the 2 million year o ...

''. The name ''deyiremeda'' derives from the Afar language meaning "close relative" because, existing so early in time, the discoverers considered ''A. deyiremeda'' to have been closely related to future australopiths. However, though the proposed distinguishing characteristics are apparently statistically significant, given how few specimens of ''A. deyiremeda'' exist, it is unclear if this indeed warrants species distinction or if these specimens simply add to the normal range of variation for ''A. afarensis''. If it is a valid species, then it could possibly indicate some ''A. afarensis'' specimens are currently classified into the wrong species. Haile-Selassie and colleagues noted that, though it shares many similarities with the

robust Robustness is the property of being strong and healthy in constitution. When it is transposed into a system, it refers to the ability of tolerating perturbations that might affect the system’s functional body. In the same line ''robustness'' ca ...

'' Paranthropus'', it may not have been closely related because it lacked enlarged molars which are characteristic of ''Paranthropus''.

Anatomy

Despite being so early, the jaws of ''A. deyiremeda'' show some similarities to those of the later ''

Homo ''Homo'' () is the genus that emerged in the (otherwise extinct) genus '' Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely relat ...

'' and ''Paranthropus''. The jaw jutted out somewhat ( prognathism) at perhaps a 39-degree angle, similar to most other early

hominin The Hominini form a taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera ''Homo'' (humans) and '' Pan'' (chimpanzees and bonobos) and in standard usage excludes the genus ''Gorilla'' (gorillas). The ...

s. The cheekbone is positioned more forward than most ''A. afarensis'' specimens. Unlike ''A. afarensis'' but like ''Paranthropus'', the walls of the cheek teeth are inclined rather than coming straight up. The upper

canines Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** ''Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the surn ...

are proportionally smaller than those of other ''Australopithecus'', but are otherwise morphologically similar to those of '' A. anamensis''. The cheek teeth are quite small for an early hominin, and the first molar is the smallest reported for an adult Pliocene hominin. Nonetheless, the enamel was still thick as other early hominins, and the enamel on the second molar is quite high and more similar to '' P. robustus''. The jawbone, though small, is

robust Robustness is the property of being strong and healthy in constitution. When it is transposed into a system, it refers to the ability of tolerating perturbations that might affect the system’s functional body. In the same line ''robustness'' ca ...

and more similar to that of ''Paranthropus''. Burtele foot

In 2012, a 3.4-million-year-old partial foot, BRT-VP-2/73, was recovered from Woranso–Mille. It strongly diverges from contemporary and later hominins by having a dextrous big toe like the earlier ''

Ardipithecus ramidus ''Ardipithecus ramidus'' is a species of australopithecine from the Afar region of Early Pliocene Ethiopia 4.4 million years ago (mya). ''A. ramidus'', unlike modern hominids, has adaptations for both walking on two legs ( bipedality) and life i ...

'', and consequently has not been assigned to a species. Though more diagnostic facial elements have since been discovered in the area, they are not clearly associated with the foot.

Palaeoecology

''A. deyiremeda'' features a strong jawbone and thick enamel, consistent with a diet of tough

sedge The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus '' Carex'' ...

s and similar foods which australopiths are generally thought to have primarily subsisted upon. The enamel on the upper incisor, canine and first premolar exhibits hypoplasia, probably caused by a period of malnutrition or illness during enamel growth in infancy while the teeth were still growing. ''A. deyiremeda'' was likely a

generalist A generalist is a person with a wide array of knowledge on a variety of subjects, useful or not. It may also refer to: Occupations * a physician who provides general health care, as opposed to a medical specialist; see also: ** General pract ...

feeder. ''A. deyiremeda'' and ''A. afarensis'' may have exhibited

niche partitioning In ecology, niche differentiation (also known as niche segregation, niche separation and niche partitioning) refers to the process by which competing species use the environment differently in a way that helps them to coexist. The competitive exclu ...

given they cohabited the same area. That is, given dental and chewing differences, they may have had different dietary and/or habitat preferences, unless these differences were simply a product of

genetic drift Genetic drift, also known as allelic drift or the Wright effect, is the change in the frequency of an existing gene variant (allele) in a population due to random chance. Genetic drift may cause gene variants to disappear completely and there ...

. Much like chimpanzees and gorillas which have more or less the same diet and inhabit the same areas, ''A. deyiremeda'' and ''A. afarensis'' may have shared typical foods when in abundance, and resorted to different fallback foods in times of food scarcity. The

Lomekwi Lomekwi 3 is the name of an archaeological site in Kenya where ancient stone tools have been discovered dating to 3.3 million years ago, which make them the oldest ever found. Discovery In July 2011, a team of archeologists led by Sonia Harma ...

stone-tool

industry Industry may refer to: Economics * Industry (economics), a generally categorized branch of economic activity * Industry (manufacturing), a specific branch of economic activity, typically in factories with machinery * The wider industrial sector ...

from northern Kenya is loosely associated with the Middle Pliocene ''

Kenyanthropus ''Kenyanthropus'' is a hominin genus identified from the Lomekwi site by Lake Turkana, Kenya, dated to 3.3 to 3.2 million years ago during the Middle Pliocene. It contains one species, ''K. platyops'', but may also include the 2 million year ...

'' based on an upper jaw fragment assigned to ''Kenyanthropus'' based on forward cheekbones, three-rooted premolars, and a small first molar. Since these features are also exhibited in ''A. deyiremeda'', anthropologist Fred Spoor suggested that ''A. deyiremeda'' was actually present at the site. Identified at 3.3 million years old, the Lomekwian is the earliest culture. These knappers

flaked ''Flaked'' is an American comedy drama streaming television series created by Will Arnett and Mark Chappell. It stars Arnett as Chip, a self-appointed "guru" who falls in love. The first season consisted of eight episodes and was released on Netfl ...

off pieces of cores made of

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

, phonolite and trachyphonolite. They held the core with one hand and struck it vertically with a

hammerstone In archaeology, a hammerstone is a hard cobble used to strike off lithic flakes from a lump of tool stone during the process of lithic reduction. The hammerstone is a rather universal stone tool which appeared early in most regions of the wo ...

, which is a simple process, though more complex than the tool-making behaviours of non-human primates. The Middle Pliocene of Woranso–Mille features

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...

impalas, alcelaphins, and elephants, as well as

browsing Browsing is a kind of orienting strategy. It is supposed to identify something of relevance for the browsing organism. When used about human beings it is a metaphor taken from the animal kingdom. It is used, for example, about people browsing o ...

giraffes, tragelaphins, and forest-dwelling monkeys. The feet of the

bovid The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and caprines. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, ...

species do not seem to be specialised for any particular type of ground (such as wet, pliable, or hard), and the teeth of hoofed species indicates an equal abundance of grazers, browsers and mixed feeders. These suggest a mixed environment which features both open grasslands as well as forests probably growing on a lake- or riverside. Similar mosaic landscapes were inhabited by ''A. anamensis'' and ''A. afarensis'' who seem to have had no preferred environment.

References

External links

Human Timeline (Interactive)
– Smithsonian,

National Museum of Natural History The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...

(August 2016) {{Taxonbar, from=Q19991921 deyiremeda Pliocene primates Pliocene mammals of Africa Fossils of Ethiopia Mammals described in 2015 Fossil taxa described in 2015

Taxonomy

Anatomy

Palaeoecology

See also

References

External links