Praeanthropus

P. afarensis Credit: John Gurche.

*Praeanthropus* is an extinct genus of australopithecine hominid that lived in Kenya, Ethiopia and Chad from the Middle Pliocene to the Early Pleistocene.

## History

*P. afarensis* was first reported as *Australopithecus aff. africanus*. One skull was discovered at Laetoli by Ludwig Kohl-Larsen, a Nazi, who used it to justify their beliefs that Africans were not as evolved as Aryans without realizing the magnitude of the discovery. Edwin Hennig (1948) proposed classifying these in the genus *Praeanthropus*, but did not name a species. Hans Weinert (1950) then placed a jaw from this species into *Meganthropus africanus*, which was largely ignored. M.S. Şenyürek (1955) then suggested *P. africanus*, with more collections made in Laetoli on an early 1974 expedition led by Mary Leakey and another in Hadar from 1972-1977 by the International Afar Research Expedition (created by Maurice Taieb, Donald Johanson and Yves Coppens). These remains were well preserved and included postcrania, including some of the most famous of the genus. Johanson, White and Coppens (1978) placed the species into *Australopithecus*, with LH 4 as the lectotype and the specific epithet after the Afar Region. *P. afarensis* is reported from Koobi Fora, possibly Lothagam, Woranso-Mille, Maka, Belohdelie, Ledi-Geraru and Fejej across Kenya and Ethiopia, respectively. For a long time, it was the oldest African hominid until the description of *Ardipithecus ramidus*; *Sahelanthropus* is the current oldest African hominid.

*P. deyiremeda* was proposed by Yohannes Haile-Selassie et al. (2015) from mandibular remains from Burtele and Waytaleya of Woranso-Mille, Afar. The holotype was discovered by Mohammed Barao on March 4, 2011, with further remains discovered by fossil hunter Ato Alemayehu Asfaw. It was described as a distinct species from the contemporaneous *P. afarensis* as a part of the Late Pliocene australopith diversity that would lead to the evolution of *Homo*. The specific epithet means "close relative" in the Afar language based on it's relation to later australopithecines. However, it has been challenged due to how little specimens exist despite potentially valid differentiation. If it is valid, it could indicate some *P. afarensis* specimens are misidentified, but if it is not, it could be chalked up to individual variation and dismissed. It is likely not closely related to *Paranthropus* based on a lack of enlarged molars.

*P. bahrelghazali* (named after the Bahr el Gazel locality) was named from the specimen "Abel" (holotype) and KT12/H2 (paratype), discovered by the Franco-Chadian Paleoanthropological Mission and reported by Michel Brunet, Alain Beauvilain, Yves Coppens, Emile Heintz, Aladji Hamit Elimi Ali Moutaye and David Pilbeam. They were first assigned to *P. afarensis* based on age, discarded morphology. However, it was named in 1996. This would make it the first australopith from Central Africa, disproving the notion that they restriction to the East, and that they inhabited many environments. This population may have left East Africa through the Central African Shear Zone. However, it's validity is often discredited based on similarity to *P. afarensis*.

*P. garhi* was named in 1999 by Berhane Asfaw, Tim D. White, Owen Lovejoy, Bruce Latimer, Scott Simpson and Gen Suwa based on fossils from the Hatayae Beds of the Bouri Formation. Using Ar-Ar dating, they are 2.5 million years old. The original describers believed it to be the descendant to *P. afarensis* based on geographic and dental data. It was first described as *Australopithecus* and the direct ancestor to *Homo*, and thus as *H. garhi*. Because it was deemed unexpected for a direct ancestor at this stage, the epithet translates to "surprise" in the Afar language. However, David Strait and Frederick Grine (1999) found it was instead an offshoot from the main tree, and that them and *Homo* share no synapomorphies. *Homo* was later calibrated to emerging 2.8 million years ago, much earlier, and was disproven by the discovery of the earliest *Homo* species.

## Description

*P. afarensis* has a tall face, a delicate brow and prognathism. AL 444-2 is the one of largest skulls, around the size of a female gorilla skull. The first somewhat complete jaw was discovered in 2022, being AL 822-1, which strongly resembles a robust gorilla jaw. Unlike gorillas, the sagittal and nuchal crests do not have sexual dimorphism and are similar to chimpanzees and female gorillas. Compared to earlier hominins the incisors are reduced in breadth, with reduced canines, molar-shaped premolars, taller molars and no honing mechanism. Lucy, a *P. afarensis*, has a cranial capacity of 365-417 with AL822-1 having 374-392, AL 333-45 with 486-492 and AL 444-2 with 519-526, making an average of 445. Infants DIK-1-1 and AL 333-105 are 273-277 and 310-215, making a growth rate close to *Homo sapiens* than to chimpanzees. *P. afarensis* brains were smaller due to a prolonged but shortened development time. Their brains were likely organized like other apes due to lack of evidence otherwise. *P. afarensis* bear great sexual dimorphism, with Henry McHenry (1991) using joint sizes and leg bones to find a height of 151 centimeters (4 feet 11 inches) for men and 105 centimeters (3 feet 5 inches) for women and a weight og 44.6 kilograms (98 pounds) for men and 29.3 kilograms (65 pounds) for women, using humanlike proportions. This makes a 1.52 to 1.22 ratio when compared to modern forms, 1.37 when compared to chimpanzees and 2 for gorillas and orangutans. Femoral heads and their variation are consistent for both sexes and good for estimation. Lucy is often used as a basis for these estimations. The Laetoli trackmakers (S1, S2, G1, G2 and G3) were found to be quite large, finding: S1 at 165 centimeters (5 feet 5 inches) tall and 45 kilograms (99 pounds) in weight, S2 at 145 centimeters (4 feet 9 inches) and 39.5 kilograms (87 pounds), G1 at 114 centimeters (3 feet 9 inches) and 30 kilograms (66 pounds), G2 at 142 centimeters (4 feet 8 inches) and 39 kilograms (86 pounds) and G3 at 132 centimeters (4 feet 4 inches) and 35 kilograms (77 pounds).

*P. afarensis* DIK-1-1 bears an oval hyoid similar to chimpanzees and gorillas rather than later hominins and orangutans. This would suggest that the laryngeal air sacs are present in non-human African apes and large gibbons; these would lower the risk of hyperventilation when producing faster extended call sequences by rebreathing exhalation from the air sacs, with speech later down forcing this adaptation to disappear due to talking making hyperventilation risks greater. Australopiths were first posited to have had weaker spines, but the thickness of the cervicals in KSD-VP-1/1 are similar to modern forms, with a bulge that gains the greatest girth at C5-6 (associated with the bracial plexus) present that may have advanced motor functions in the hands and precision tasks possibly attributable to tool use and production. However, this may also cause head stability or posture. AL 333-101 and 333-106 lack evidence for this. KDS-VP-1/1 indicates the nuchal ligament had a bell-shaped ribcage, with the upper ribcage constricting similar to *Homo*. The centra found in Lucy were interpreted as T6, 8, 10, 11 and L3 but a 2015 study finds them to be T6-7. 9-10 and L3. DIK-1-1 shows that australopiths has 12 thoracics. Like *Homo*, *P. afarensis* bore 5 lumbars in a long and flexible series, unlike other apes. *P. afarensis* bears a mosaic of traits in the arms. The pelvis and legs are clearly built for sustaining weight and therefore habitual bipedalism and the arms are similar to *Pongo* and thus arboreality. However. these are debated as these adaptations may be retained and a lack of pressures retained them. The shoulder is in somewhat of a shrug closer to the head, with juvenile *Homo sapiens* having a similar anatomy based on smaller size, but the discovery of *Homo floresiensis* with a modern configuration and new, larger specimens show this not to be a rule. The scapular spine is closer to a gorilla's range. *P. afarensis* bears various brachial indexes comparable to other apes (upper estimate) and *Homo sapiens* (lower estimate). however, L40-19 has a much longer ulna that is below the range of *Pongo* and gibbons, with AL 438-1 having metacarpals proportionally similar to *Pongo* and *Homo sapiens*. *P. afarensis* has a somewhat modern hand with some arboreal adaptations such as stronger finger flexion and not being able to carry spherical/cylindrical objects as well. They would have had precision grip necessary for tool use, but it is unclear if the hand is capable of producing tools.

Lucy's pelvic inlet is 132 millimeters wide and about the same breadth as *Homo sapiens*, which is a likely adaptation to minimize a center of mass drop while walking bipedal with shorter legs. Rotating hips may have been more important in *P. afarensis*. The pelvic inlet would reduce later down the lineage due to leg elongation. Newborns would have had similar or smaller head sizes than newborn chimpanzee. It is unknown if the platypelloid pelvis reduced leverage in the hamstrings. *P. afarensis* has a hell that bears the same adaptations for bipedalism and a developed grade of walking. The big toe was not as dexterous which would have made walking more energy efficient at the expense of arboreality and not being able to grasp tree limbs. However, DIK-1-1, an infant, has some mobility in the big toe, though not as much as other apes, that would have reduced walking efficiency but enhanced climbing for food and safety, or possibly for clinging to an adult. *P. garhi* bears a cranial capacity of 450, with a sagittal crest running down the midline of the skull and a prognathic jaw. The postcanines, molars and premolars are massive, similar to other australopithes and *Paranthropus robustus*. *P. garhi* bears a humanlike humerus-femur ratio and an apelike brachial index, which, like *P. afarensis*, indicates walking and arboreality. BOU-VP-35/1, a humerus, is notably larger than BOU-VP-12/1, which may be size-specific sexual dimorphism similar to *P. afarensis*. However, it may just be standard size variation. BOU-VP-12/130 is considered male and BOU-VP-17/1 female. Contemporaneous hominins are about the same size, and BOU-VP-17/1 may have been 140 centimeters tall. *P. garhi* bears elongate legs unlike other australopiths, which indicates in *Homo sapiens* a delayed adolescent growth spurt; *P. garhi* may have had a slower growth rate or a more rapid leg development rate.

*P. deyiremeda* bears similarities with *P. afarensis*, later *Homo* and *Paranthropus*. The jaw is prognathic at about a 39°, similar to similar species. The cheek is placed more forwards than most *P. afarensis*, but unlike it and *Paranthropus*, the cheek teeth walls are at an incline. The upper canines are smaller than *Australopithecus*, but similar to *A. anamensis*. The cheek teeth are small, with he first molar being the smallest of any adult Pliocene hominin. The enamel is still just as thick, with the second molar being high and similar to *Paranthropus robustus*. The jaw is small and more similar to *Paranthropus*. BRT-VP-2/73 from Woranso-MIlle strongly diverges from later hominins by having a dexterous big toe like *Ardipithecus ramidus*, and such has not been assigned a species. Diagnostic facial elements from the same area are not clearly associated with this specimen. *P. bahrelgazhali* KT12/H1 are similar to *P. afarensis* with large incisor-like canines and bicuspid premolars. However, the alveoli are nearly vertical, and has a poorly developed superior transverse torus, thin enamel on the chewing surface of the premolars and moderate inferior torus. Brunet et al. find 3 distinct tooth roots that may distinguish it as a species. However *P. afarensis* LH-24 was described later as having the same features, which shows a highly variable *P. afarensis* morphotype. KT40 and KT12/H1 bear the same dimensions as the mandibular symphysis of *P. afarensis* (though theirs are thicker when compared to height). Both *P. deyiremeda* and *P. bahrelghazali* are often considered an extension of variability in *P. afarensis*.

## Paleobiology

Human public lice likely evolved around 3.3 million years ago due to contact between hominins similar to *Praeanthropus* and gorillas, probably, but not limited to, either butching and consumption of gorillas or use of gorilla nests. Since pubic hair is coarse in both species, it seems likely that they found a niche in the hominin lineage.

### Technology

An ungulate rib discovered from Dikika in 2009 and a partial femur of a goat-sized juvenile bovid bore cut marks and some crushing in the femur, which were initially interpreted as butchering with stone tools. If this is correct, this makes sharp-edged stone tool use dates to at least 3.4 million years ago and would make it attributable to *P. afarensis*. It is the only known species from this time and place, but the fossils were discovered from a sandstone unit, which may have caused abrasive marks from sand and gravel and thus make this attribution weak. *P. garhi* was not found with tools but mammalian bones have cut and percussion marks made from stone tools, with the left mandible of an alcelaphine with three successive, unambiguous cuts that were presumably made while removing the tongue, a bovid tibia with cuts, chops and impact scars from a hammerstone that may have been made to extract marrow and a *Hipparion* femur with cuts consistent with dismembering and filleting are found. Stone tools likely did not preserve because the Hatayae was likely featureless, grassy and a lake margin with few raw materials to make tools with. It is possible therefore that they were creating and carrying tools across distances to butchering sites, using many times before discarding. This would disprove the theory that only *Homo* could manufacture. However, it is also possible that the tools were not manufactured but rather just sharp rocks. The Gona site, nearby, has many raw materials, with Oldowan discovered from 1992-1994, dating 2.6-2.5 million years old and the oldest evidence of manufacturing at the time. Since *P garhi* dates to this time, they are attributed. However, the discovery of LD 350-1 and associated tools push the emergence of *Homo* and stone tool use is pushed further back. Other australopiths are credited with bone tool manufacturing, such as 3.4 million year old cuts attributed to *P. afarensis* discovered in 2010 and *Kenyanthropus*.

### Diet

*P. afarensis* was likely a generalist omnivore. 3.4-2.9 million-year-old carbon isotope analysis on teeth from Hadar and Dikika suggest a wide-ranging diet between specimens, with forest dwellers preferring C3 forest plants and bush/grassland dwellers with C4 CAM savanna plants (grass, seeds, roots, storage organs, succulents and maybe the animals that ate those such as termites). Thus, *P. afarensis* would have exploited a variety of resources that forest dwelling *Ardipithecus ramidus*, *A. anamensis* and modern savanna chimpanzees do. *P. afarensis*, based on microwear, infrequently consumed hard, brittle foods, probably as fallback. *P. garhi* and *P. afarensis* bear durable teeth that may have helped in eating harder foods in leaner times rather than their normal diet.

### Life History

A different birthing mechanism may have had the neonate enter the inlet laterally and exiting the pelvis through the outlet. This would be non-rotational, but it has been suggested that the shoulders would have obstructed movement, thus making it enter the cavity transversely, rotating to exit. This would then make it semi-rotational birth, where there may not have been much space to pass the neonate through the birth canal, causing difficult childbirth.

### Locomotion

The Laetoli trackway indicates developed bipedal locomotion, more efficient than the bent-hip-bent-knee (BHBK) used by other apes, though early interpretations include BHBK or a shuffling movement. The trail consists of short and broad prints resembling a 2.5 year-old child, though it has also been suggested to be made from *Agriotherium africanus*. G1 consists of four cycles made likely by a child. G2 and 3 are made by a pair of adults. In 2014, 2 more trackways were discovered, made by one individual; S1, extending 32 meters. A single footprint, S2, was discovered in 2015. They are shallow, which indicates a flexed limb posture when the foot collides with the ground and maybe a less arched foot. *P. afarensis* would have been less efficient at bipedal walking. Some tracks have a 100 millimeter-long drag mark that was probably left by the heel, which may indicate the foot was lifted at a low angle. The weight appears to shift from the heel to the side of the foot and then the toes at push-off. Some fo S1 indicates asymmetrical walking where weight is placed at the anterolateral before toe-off, or sometimes where the body rotates mid-step. The angle of the gait is 2–11° for both sides. G1 generally has wide and asymmetrical angles as opposed to others who typically have low angles. G1 has a speed reported at 0.47, 0.56, 0.64, 0.7 and 1 miles/second (1.69, 2, 2.3, 2.5 and 3.6 kilometer/hour; 1.1, 1.3, 1.4, 1.6 and 2.2 miles per hour), G2/3 are reported at 0.37, 0.84 and 1 miles/seconds (1.3, 2.9 and 3.6 kilometers/hour; 0.8, 1.8 and 2.2 miles per hour) and S1 reported at 0.51 or 0.93 miles/second (1.8 or 3.3 kilometers/hour; 1.1 or 2.1 miles per hour). The average step distance is 568 millimeters and a stride distance t 1139 millimeters. S1 may have the highest average step-and-stride length of 505-660 millimeters and 1044-1284 millimeters, respectively, where G1-3 average 416, 453 and 433 millimeters for step and 829, 880 and 876 millimeters for stride. The largest individual was nicknamed "Chewie". A 2022 study tested the bipedal ability of Lucy, concluding that that the hip was more cartilaginous as not to restrict movement in the trees and on the ground. It was unable to be extended like humans, but could overall employ a bent-hip bent-knee style walking.

### Paleopathology

Lucy bears marked thoracic kyphosis and diagnosed with Scheuermann's disease, which was likely caused by over straining and leading to a hunched posture due to irregular curving of the spine. Because it is similar to modern human patients, this would indicate a basically human range of locomotor function when walking. The straining may have occurred while climbing or swinging in trees, though if this is disproven it would make the maladaptive assumptions incorrect. KSD-VP-1/1 may have compensatory action in the cervicals and lumbars (gooseneck) consistent with thoracic kyphosis and Scheuermann's disease. However, thoracics are not preserved in the specimen. KSD-VP-1/1 was found in 2010 to have had a valgus deformity of the left ankle involving the fibula, with a bony ring on the fibular joint surface, extending the bone 5-10 millimeters. This was likely caused by a fibular fracture during childhood and healed in a nonunion. John Kappelman (2016) argued that the fracturing in Lucy is consistent with a proximal humerus fracture, often caused by falling. He concluded that Lucy died while falling from a tree, and that *P. afarensis* slept in trees or climbed into trees to escape from predators. However, similar fracturing is found in many local herbivores (antelopes, elephants, giraffes and rhinos) and may be taphonomic bias. Lucy may also have been killed by an animal or in a mudslide. AL 333 are thought to have been deposited at around the same time and bear little evidence of carnivore activity and were buried in a 7-meter hill stretch. James Louis Aronson and Taieb (1981) suggested a flash flood. Paul Pettitt considered natural causes unlikely and speculated in 2013 that their corpses were cached in tall grass by their contemporaries. This is documented in modern primates, and may be done to the recently deceased in order to to attract predators to their territory.

## Classification

*P. afarensis* (the type) and *P. garhi* are definitive species where *P. deyiremeda* and *P. bahrelghazali* are disputed. Johanson and White (1979) suggested *P. afarensis* was the common ancestor of *Homo* and *Paranthropus*, then with debates surrounding it's validity. The species was then split into various species of *Homo* before being ignored. Analyses find that *P. afarensis* and *P. garhi* cluster in an offshoot group from a concestor that would further diversify into *Australopithecus*, *Paranthropus* and *Homo*. Dembo et al. (2015) finds:

## Notable Specimens

* File:Praeanthropus afarensis redraw skeletal.png  AL 129-1 "Johanson's Knee": An *P. afarensis* knee joint found in Ethiopia, dating 3.4 mya. This includes the elliptical lateral condyle and an oblique femoral shaft, indicating bipedalism. AL 129-1 was found by Donald Johanson in Ethiopia in November 1973.
* AL 200-1: *P. afarensis* found in Ethiopia, Afar locality, discovered by Ato Alemayehu Asfaw on October 17, 1974, AL 200-1 consists of an upper palate and teeth, estimated 3-3.2 mya. The arrangement of teeth is notably ape-like, in it's 1976 description.
* AL 333 "First Family": A large collection of *P. afarensis* bones found in Hadar Ethiopia by Donald Johanson in 1975, about 3.2 my-old, consisting of thirteen individuals of differing ages. Multiple theories over these deaths are proposed, none confirmed, and sexual dimorphism is debated.
* KT-12/H1 "Abel": The only specimen of *P. bahrelghazali*; named after Abel Brillanceau, close friend of the discoverer, who died of malaria in 1989. Little remains of Abel, only several teeth and part of the mandible. This specimen was found in Kanem, Chad by Michel Brunet in January 1995.
* KSD-VP-1/1 "Kadanuumuu": Meaning "Big Man" in the Afar language, 400,000 years older than "Lucy", this specimen represents a fully bipedal *P. afarensis*. This specimen was found by Yohannes Haile-Selassie in 2005.
* LH 4 "Laetoli Hominid 4": A fossilized mandible and teeth found in Laetoli, Tanzania by Mary Leakey in 1974. It is the lectotype of *P. afarensis*.
* AL 288-1 "Lucy"/"Dink[i]nesh": Several hundred pieces of fragmented skeleton, originating from one female individual. About 40% was recovered. She is among the most well-known of all specimens. Lucy was found by Johanson, Taieb, Coppens and Gray in Afar, Ethiopia on November 24, 1974 . Bite marks from *Crocodylus* suggest this individual was killed by and dragged into water by crocodilians.
* BRT-VP-2/73 "Burtele foot": The Burtele foot consists of pedal elements recovered from east Africa. These are ~3.4 million years old, but does not match the contemporaneous species *P. afarensis*, but does resemble *Ardipithecus ramidus*. It has an opposable big toe. This indicates at least one hominin in the Late Pliocene, but also indicates *A. ramidus*-like locomotion persisting into the Late Pliocene.
* BEL-VP-1/1: A frontal fragment from Middle Awash, Afar. It is 3.9 million years old and is typically assigned to *A. anamensis* based on age, but may be assignable instead to *P. afarensis* due to derived postorbital constriction. This would mean that the latter and *P. afarensis* coexisted for at least 100,000 years.
* AL 438-1: A second adult *P. afarensis* specimen with cranium and postcrania from Hadar, discovered in 2005.
* DIK-1/1 or DIK-1-1 "Selam": The remains of a 3-year-old female *P. afarensis*. Often called "Lucy's Baby", lived 120,000 years later than Lucy. Selam was found in Afar, Ethiopia by Zeresenay Alemseged in 2000.

## Species

* *P. afarensis*
* *P. garhi*
* *P. deyiremeda*? (=*P. afarensis*?)
* *P. bahrelghazali* (=*P. afarensis*?)

### Reassigned Species

* *"P." africanus*
* *"P." anamensis*
* *"P." prometheus*
* *"P. tugenensis*
* *"P." boisei*
* *"P." robustus*
* *"P." praegens*

## Synonyms

* *Australopithecus afarensis*
* *Australopithecus garhi*
* *Australopithecus deyiremeda*
* *Australopithecus bahrelghazali* (=*P. afarensis*?)
* *Meganthropus africanus* (=*P. afarensis*)
* *Homo aethiopicus* (=*P. afarensis*)
* *Homo hadar* (=*P. afarensis*)
* *Homo garhi* (=*P. garhi*)
* *Präeanthropus* (amended)
* *Prăanthropus* (amended)
* *Australopithecus africanus afarensis*

## Paleoecology

*P. afarensis* lived in grasslands, woodlands, shrublands and lake/riverside forests where the animal assemblages vary. Pliocene East Africa was warm and wet compared to the Miocene, with the dry season lasting for about 4 month, based on vegetation, biota and geology. Rainy seasons were extended and would have made desireable foods available for most of the year. 3-4 million years ago, Africa had a large carnivore diversity greater than today, and australopithecines were often prey items to large cats such as *Panthera* and machairodonts and hyenas. Australopiths and early *Homo* preferred cool environments, since no australopithecines are found below 1000 meters at deposition time. Like chimpanzees, they lived in areas with an average diurnal temperature of 25 °Celsius (77 °Fahrenheit), dropping to a nocturnal temperature of 10 or 5 °Celsius (50 or 41 °Fahrenheit). Hadar, 3.4-2.95 million years ago, has a temperature of 20.2 °Celsius (68.4 °Fahrenheit). The Middle Pliocene of Woranso-Mille has grazing impalas, alcelaphins and elephants with browsing giraffes, tragelephins and forest-dwelling monkeys. Bovid feet from here tend not to be developed to a particular ground type, and the teeth of ungulates indicates equal abundance of grazers, browsers and mixed feeders. This suggests a mixed environment with open grasslands and forests growing on a lake/riverside. *A. anamensis* and *P. afarensis* seem not to prefer a specific environment.

Lake Chad was expanded during the Pliocene, "Lake Mega-Chad", with insect traces indicating diverse flora and many rhizomes may suggest a seasonal climate with wet and dry seasons. Koro Toro yields antelopes, some of which endemic, *Loxodonta*, rhinoceros, *Kolpochoerus afarensis*, *Hipparion*, *Sivatherium* and giraffes. Some of these are from the Pliocene of East Africa, implicating a migration between the east and west of the Great African Rift. K13 bears abundant reduncines, alcelaphines, antilophines and rarer tragelaphines, indicating an open environment that was drier than the Pliocene of East Africa. It was mostly grasslands with some trees, with catfish, fish, *Hexaprotodon protamphibius*, tortoises, *Trionyx*, the false gharial and anatids in the waters These indicate open-water lakes or streams with swampy grassy margins that connected to the Nilo-Sudan waterways. Koro Toro may have been similar to the modern Okavango Delta.

## Gallery

### Reconstructions

Child *P. afarensis*.
**Credit: Viktor Dèak.**Adult male *P. afarensis*.
**Credit: Viktor Dèak.**Lateral view of Lucy.
**Credit: John Gurche.**
## References

1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 https://en.wikipedia.org/wiki/Australopithecus\_afarensis
2. ↑ 2.0 2.1 2.2 https://en.wikipedia.org/wiki/Australopithecus\_bahrelghazali
3. ↑ 3.0 3.1 3.2 3.3 https://en.wikipedia.org/wiki/Australopithecus\_garhi
4. ↑ https://www.frontiersin.org/articles/10.3389/fevo.2021.639048/full
5. ↑ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2687769/
6. ↑ https://link.springer.com/article/10.1186/1741-7007-5-7
7. ↑ https://www.scientificamerican.com/article/meet-chewie-the-biggest-australopithecus-on-record1/
8. ↑ https://academic.oup.com/iob/article/4/1/obac031/6651280?login=false
9. ↑ https://royalsocietypublishing.org/doi/10.1098/rspb.2015.0943
10. ↑ https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.23387
11. ↑ https://en.wikipedia.org/wiki/AL\_129-1
12. ↑ https://en.wikipedia.org/wiki/AL\_200-1
13. ↑ https://en.wikipedia.org/wiki/AL\_333
14. ↑ https://en.wikipedia.org/wiki/Abel\_(hominid)
15. ↑ https://en.wikipedia.org/wiki/Kadanuumuu
16. ↑ https://en.wikipedia.org/wiki/LH\_4
17. ↑ https://en.wikipedia.org/wiki/Lucy\_(Australopithecus)
18. ↑ https://www.nature.com/articles/nature10922
19. ↑ https://en.wikipedia.org/wiki/Selam\_(Australopithecus)
20. ↑ https://books.google.ca/books?id=440TmWXToLAC&dq=%22proanthropus%22&source=gbs\_navlinks\_s
21. ↑ https://vertpaleo.org/wp-content/uploads/2021/10/SVP\_2021\_VirtualBook\_final.pdf