Australopithecines

@article{legrosclark1950homonid2,
    author = "Le Gros Clark, W. E",
    title = "Homonid characters of the australopithecine dentition",
    year = "1950",
    journal = "Journal of the Royal Anthropological Institute of Great Britian and Ireland, v. 80, p. 37-53",
    note = "talkorigins\_source = {true}; raw\_reference = {Le Gros Clark, W. E., 1950, Homonid characters of the australopithecine dentition: Journal of the Royal Anthropological Institute of Great Britian and Ireland, v. 80, p. 37-53.}"
}

@article{doi101038258389a0,
    author = "Oxnard, C.",
    title = "The place of the australopithecines in human evolution: grounds for doubt?",
    year = "1975",
    journal = "Nature",
    url = "https://www.semanticscholar.org/paper/a3c0981742c2df4d945e3554857323646b5253ad",
    doi = "10.1038/258389A0",
    is_oa = "true",
    number = "5534",
    pages = "389-395",
    semanticscholar_citation_count = "64",
    semanticscholar_id = "a3c0981742c2df4d945e3554857323646b5253ad",
    volume = "258"
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@misc{oxnard1975the4,
    author = "Oxnard, C",
    title = "The Place of the Australopithecines in Human Evolution",
    year = "1975",
    howpublished = "Grounds for Doubt?: Nature, v. 258, p. 386-394",
    note = "talkorigins\_source = {true}; raw\_reference = {Oxnard, C., 1975, The Place of the Australopithecines in Human Evolution: Grounds for Doubt?: Nature, v. 258, p. 386-394.}"
}

@book{oxnard1975uniqueness5,
    author = "Oxnard, C. E",
    title = "Uniqueness and Diversity in Human Evolution",
    year = "1975",
    publisher = "Morphometric Studies of Australopithecines: Chicago, Ill., University of Chicago Press, 133 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Oxnard, C. E., 1975, Uniqueness and Diversity in Human Evolution: Morphometric Studies of Australopithecines: Chicago, Ill., University of Chicago Press, 133 p.}"
}

@article{doi1023072800448,
    author = "Bilsborough, Alan and Oxnard, Charles",
    title = "Uniqueness and Diversity in Human Evolution: Morphometric Studies of Australopithecines.",
    year = "1976",
    journal = "Man",
    url = "https://doi.org/10.2307/2800448",
    doi = "10.2307/2800448",
    openalex = "W588901157"
}

@misc{nickels1986creationists3,
    author = "Nickels, M. K",
    title = "Creationists and Australopithecines",
    year = "1986",
    howpublished = "Creation/Evolution, v. 19, p. 1-15",
    note = "talkorigins\_source = {true}; raw\_reference = {Nickels, M. K., 1986, Creationists and Australopithecines: Creation/Evolution, v. 19, p. 1-15.}"
}

@misc{conway1990endocranial1,
    author = "Conway, G. C. and Vannier, M. W. and Tobias, P. V",
    title = "Endocranial features of Australopithecus africanus revealed by 2- and 3-D computed tomography",
    year = "1990",
    howpublished = "Science, v. 247, p. 838",
    note = "talkorigins\_source = {true}; raw\_reference = {Conway, G. C., Vannier, M. W., and Tobias, P. V., 1990, Endocranial features of Australopithecus africanus revealed by 2- and 3-D computed tomography: Science, v. 247, p. 838.}"
}

@article{aiello2000the,
    author = "Aiello, L. C. and Andrews, P.",
    title = "The australopithecines in review",
    year = "2000",
    journal = "Human Evolution",
    url = "https://doi.org/10.1007/bf02436232",
    doi = "10.1007/bf02436232",
    number = "1-2",
    pages = "17-38",
    volume = "15"
}

This dissertation investigates debates in the early and middle parts of the twentieth century over the significance of the Australopithecine fossils discovered in South Africa. The initial specimen, famously known as the Taung Child, was characterized by Raymond Dart in 1925 as a possible evolutionary ancestor of human beings, linking our species to a distant past in which our anatomical similarity to the apes was much more conspicuous. Most of the recognized scientific authorities disagreed with Dart's assessment, instead seeing the specimen as a mere extinct ape, without any special place in humankind's evolutionary history. My narrative examines the debates that ensued over the next three and a half decades, closely following the changing credibility of Dart's initial claim, as well as subsequent claims by Dart and other scientists about the Australopithecines, through the shifting networks of objects, texts, people, practices and institutions that made up the infrastructure of paleoanthropological knowledge. The narrative demonstrates that the determinants of credibility in the Australopithecine debates were strongly tied to the particulars of local circumstances and personal relationships, and cannot be reduced to any normative, a priori account of how credibility is or ought to be achieved in science

@article{s2fd073be530c35b82265e3a28376c77c620d552a1,
    author = "Richmond, Jesse",
    title = "Experts and australopithecines : credibility and controversy in the science of human evolution, 1924-1959",
    year = "2009",
    journal = "Schweizerische Rundschau fur Medizin Praxis = Revue suisse de medecine Praxis",
    abstract = "This dissertation investigates debates in the early and middle parts of the twentieth century over the significance of the Australopithecine fossils discovered in South Africa. The initial specimen, famously known as the Taung Child, was characterized by Raymond Dart in 1925 as a possible evolutionary ancestor of human beings, linking our species to a distant past in which our anatomical similarity to the apes was much more conspicuous. Most of the recognized scientific authorities disagreed with Dart's assessment, instead seeing the specimen as a mere extinct ape, without any special place in humankind's evolutionary history. My narrative examines the debates that ensued over the next three and a half decades, closely following the changing credibility of Dart's initial claim, as well as subsequent claims by Dart and other scientists about the Australopithecines, through the shifting networks of objects, texts, people, practices and institutions that made up the infrastructure of paleoanthropological knowledge. The narrative demonstrates that the determinants of credibility in the Australopithecine debates were strongly tied to the particulars of local circumstances and personal relationships, and cannot be reduced to any normative, a priori account of how credibility is or ought to be achieved in science",
    url = "https://www.semanticscholar.org/paper/fd073be530c35b82265e3a28376c77c620d552a1",
    is_oa = "true",
    openalex = "W7111210",
    semanticscholar_citation_count = "4",
    semanticscholar_id = "fd073be530c35b82265e3a28376c77c620d552a1"
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@misc{s2cae1ff17b23113f0992d2318c874e17453ed6c5c,
    author = "Butzer, K.",
    title = "RECENT THINKING ON HUMAN EVOLUTION Paleoecology of South African Australopithecines:",
    year = "2010",
    url = "https://www.semanticscholar.org/paper/cae1ff17b23113f0992d2318c874e17453ed6c5c",
    is_oa = "true",
    semanticscholar_id = "cae1ff17b23113f0992d2318c874e17453ed6c5c"
}

@incollection{clarke2014australopithecines,
    author = "Clarke, Ronald J.",
    title = "Australopithecines",
    year = "2014",
    booktitle = "Encyclopedia of Global Archaeology",
    url = "https://doi.org/10.1007/978-1-4419-0465-2\_684",
    doi = "10.1007/978-1-4419-0465-2\_684",
    pages = "697-702"
}

In paleoanthropology the group of hominids known as the "robust" australopithecines has emerged as one of the most interesting. Through them we have the opportunity to examine the origin, natural history, and ultimate extinction of not just a single species, but of an entire branch in the hominid fossil record. It is generally agreed that the human lineage can be traced back to this group of comparatively small-brained, large-toothed creatures. This volume focuses on the evolutionary history of these early hominids with state-of-the-art contributions by leading international authorities in the field. Although a case can be made for a "robust" lineage, the functional and taxonomic implications of the morphological features are subject to vigorous disagreement. An area of lively debate is the possible causal relationship between the presence of early Homo and the origin, evolution, and virtual extinction of "robust" australopithecines.This volume summarizes what has been learned about the evolutionary history of the "robust" australopithecines in the 50 years since Robert Broom first encountered the visage of a new kind of ape-man from Kromdraai. New discoveries from Kromdraai to Lomekwi have served to keep us aware that the paleontological record for hominid evolution is hardly exhausted. Because of such finds no single volume can hope to stand as a summary on the "robust" australopithecines for very long, but this classic volume comes close to achieving this goal. The book sheds new light upon some old questions and also acts to provide new questions. The answers to those questions bring us closer to a fuller understanding and appreciation of the origins, evolution, and ultimate demise of the "robust" australopithecines. Since the "robust" australopithecines most likely stand as our closest relatives, a better understanding of their origin, history, and demise serves to provide heightened appreciation of the course of human evolution itself. This definitive volume addresses the questions and problems surrounding this important lineage.

@book{doi1043249780203792667,
    author = "Grine, Frederick E.",
    title = "Evolutionary History of the Robust Australopithecines",
    year = "2017",
    abstract = {In paleoanthropology the group of hominids known as the "robust" australopithecines has emerged as one of the most interesting. Through them we have the opportunity to examine the origin, natural history, and ultimate extinction of not just a single species, but of an entire branch in the hominid fossil record. It is generally agreed that the human lineage can be traced back to this group of comparatively small-brained, large-toothed creatures. This volume focuses on the evolutionary history of these early hominids with state-of-the-art contributions by leading international authorities in the field. Although a case can be made for a "robust" lineage, the functional and taxonomic implications of the morphological features are subject to vigorous disagreement. An area of lively debate is the possible causal relationship between the presence of early Homo and the origin, evolution, and virtual extinction of "robust" australopithecines.This volume summarizes what has been learned about the evolutionary history of the "robust" australopithecines in the 50 years since Robert Broom first encountered the visage of a new kind of ape-man from Kromdraai. New discoveries from Kromdraai to Lomekwi have served to keep us aware that the paleontological record for hominid evolution is hardly exhausted. Because of such finds no single volume can hope to stand as a summary on the "robust" australopithecines for very long, but this classic volume comes close to achieving this goal. The book sheds new light upon some old questions and also acts to provide new questions. The answers to those questions bring us closer to a fuller understanding and appreciation of the origins, evolution, and ultimate demise of the "robust" australopithecines. Since the "robust" australopithecines most likely stand as our closest relatives, a better understanding of their origin, history, and demise serves to provide heightened appreciation of the course of human evolution itself. This definitive volume addresses the questions and problems surrounding this important lineage.},
    url = "https://doi.org/10.4324/9780203792667",
    doi = "10.4324/9780203792667",
    openalex = "W622903023"
}

@article{doi101038s415860180127x,
    author = "González-Forero, Mauricio and Gardner, Andy",
    title = "Inference of ecological and social drivers of human brain-size evolution",
    year = "2018",
    journal = "Nature",
    url = "https://www.semanticscholar.org/paper/c012d6b08f1a02dfb7d145123c0148c723af6a44",
    doi = "10.1038/s41586-018-0127-x",
    is_oa = "true",
    number = "7706",
    pages = "554-557",
    semanticscholar_citation_count = "184",
    semanticscholar_id = "c012d6b08f1a02dfb7d145123c0148c723af6a44",
    volume = "557",
    references = "doi101016jtics201705011"
}

@incollection{clarke2019australopithecines,
    author = "Clarke, Ronald J.",
    title = "Australopithecines",
    year = "2019",
    booktitle = "Encyclopedia of Global Archaeology",
    url = "https://doi.org/10.1007/978-3-319-51726-1\_684-2",
    doi = "10.1007/978-3-319-51726-1\_684-2",
    pages = "1-7"
}

@incollection{clarke2020australopithecines,
    author = "Clarke, Ronald J.",
    title = "Australopithecines",
    year = "2020",
    booktitle = "Encyclopedia of Global Archaeology",
    url = "https://doi.org/10.1007/978-3-030-30018-0\_684",
    doi = "10.1007/978-3-030-30018-0\_684",
    pages = "1222-1228"
}

This paper presents a detailed analysis of the endocast of one of the most complete Paranthropus robustus crania known, DNH 7, from the Drimolen site (South Africa), and compares it with the morphology of other australopithecine endocasts. We focus on endocranial volume, the impressions of cortical sulci, cranial sutures, and the pattern of cranial venous sinuses on the endocast. A noteworthy observation is the estimated endocranial capacity of 403 cm3, which is small for an adult Paranthropus. Fragmentary sulci identified in the frontal and temporal lobes of DNH 7 exhibit similarities with patterns observed in chimpanzees and gracile australopithecines. We observe the presence of a large remnant of an occipital-marginal sinus on DNH 7 and provide an updated table of 13 Paranthropus endocasts that are scorable for this trait, which reinforces the hypothesis that an enlarged occipital-marginal (O/M) sinus system was fixed across the three species of Paranthropus. In light of this, the possible functional significance of the occipital-marginal sinus system is reevaluated considering the ontogenetic development of cranial venous blood flow in human children. This leads us to hypothesize that the ontogenetic development of cranial blood flow in Paranthropus and Australopithecus africanus infants were different and to suggest that Taung 1 was the only A. africanus specimen known to have exhibited an enlarged O/M sinus system because it was an immature individual.

@article{doi101002ajpa25010,
    author = "Falk, Dean and Marom, Assaf",
    title = "The DNH 7 endocast of Paranthropus robustus from Drimolen, South Africa: Reconsidering the functional significance of an enlarged occipital-marginal (O/M) sinus system in robust australopithecines.",
    year = "2024",
    journal = "American journal of biological anthropology",
    abstract = "This paper presents a detailed analysis of the endocast of one of the most complete Paranthropus robustus crania known, DNH 7, from the Drimolen site (South Africa), and compares it with the morphology of other australopithecine endocasts. We focus on endocranial volume, the impressions of cortical sulci, cranial sutures, and the pattern of cranial venous sinuses on the endocast. A noteworthy observation is the estimated endocranial capacity of 403 cm3, which is small for an adult Paranthropus. Fragmentary sulci identified in the frontal and temporal lobes of DNH 7 exhibit similarities with patterns observed in chimpanzees and gracile australopithecines. We observe the presence of a large remnant of an occipital-marginal sinus on DNH 7 and provide an updated table of 13 Paranthropus endocasts that are scorable for this trait, which reinforces the hypothesis that an enlarged occipital-marginal (O/M) sinus system was fixed across the three species of Paranthropus. In light of this, the possible functional significance of the occipital-marginal sinus system is reevaluated considering the ontogenetic development of cranial venous blood flow in human children. This leads us to hypothesize that the ontogenetic development of cranial blood flow in Paranthropus and Australopithecus africanus infants were different and to suggest that Taung 1 was the only A. africanus specimen known to have exhibited an enlarged O/M sinus system because it was an immature individual.",
    url = "https://pubmed.ncbi.nlm.nih.gov/39150888/",
    doi = "10.1002/ajpa.25010",
    pmid = "39150888"
}

Various selection pressures have shaped human uniqueness, for instance, music. When and why did musical universality and diversity emerge? Our hypothesis is that “music” initially originated from manipulative calls with limited musical elements. Thereafter, vocalizations became more complex and flexible along with a greater degree of social learning. Finally, constructed musical instruments and the language faculty resulted in diverse and context‐specific music. Music precursors correspond to vocal communication among nonhuman primates, songbirds, and cetaceans. To place this scenario in hominin history, a three‐phase scheme for music evolution is presented herein. We emphasize (1) the evolution of sociality and life history in australopithecines, (2) the evolution of cognitive and learning abilities in early/middle Homo, and (3) cultural evolution, primarily in Homo sapiens. Human musical capacity and products should be due to the hominin‐specific combination of several biosocial features, including bipedalism, stable pair bonding, alloparenting, expanded brain size, and sexual selection.

@article{doi101002evan22031,
    author = "Morita, Masahito and Nishikawa, Yuri and Tokumasu, Yudai",
    title = "Human musical capacity and products should have been induced by the hominin‐specific combination of several biosocial features: A three‐phase scheme on socio‐ecological, cognitive, and cultural evolution",
    year = "2024",
    journal = "Evolutionary Anthropology: Issues",
    abstract = "Various selection pressures have shaped human uniqueness, for instance, music. When and why did musical universality and diversity emerge? Our hypothesis is that “music” initially originated from manipulative calls with limited musical elements. Thereafter, vocalizations became more complex and flexible along with a greater degree of social learning. Finally, constructed musical instruments and the language faculty resulted in diverse and context‐specific music. Music precursors correspond to vocal communication among nonhuman primates, songbirds, and cetaceans. To place this scenario in hominin history, a three‐phase scheme for music evolution is presented herein. We emphasize (1) the evolution of sociality and life history in australopithecines, (2) the evolution of cognitive and learning abilities in early/middle Homo, and (3) cultural evolution, primarily in Homo sapiens. Human musical capacity and products should be due to the hominin‐specific combination of several biosocial features, including bipedalism, stable pair bonding, alloparenting, expanded brain size, and sexual selection.",
    url = "https://www.semanticscholar.org/paper/a467977437d3a368e9dedfadff476818e2b0bd3d",
    doi = "10.1002/evan.22031",
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    number = "4",
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Simple Summary The unique complexity of human childbirth is traditionally attributed to the opposing selection pressures of bipedal locomotion and large brains. Here, we explore this trade-off in Australopithecus with canonical discriminant analyses using different fetal head sizes. We reveal that the shape of the pelvis in Australopithecus led to a tight fit between the mother’s pelvis and the newborn head despite their relatively small brain sizes. To alleviate this obstetrical dilemma, australopithecines must have already given birth to secondarily altricial infants that were helpless at birth like those of extant humans. Cognitive development and some aspects of the modern life history pattern therefore likely originated prior to the appearance of the genus Homo. Abstract The origin of difficult birth is still a matter of debate in obstetrics. Recent studies hypothesized that early hominins already experienced obstructed labor even with reduced neonatal head sizes. The aim of this work is to test this hypothesis using an extant obstetrical sample with known delivery outcomes. Three delivery outcomes (i.e., instrument-assisted, Caesarean section, and vaginal birth) were evaluated using a discriminant analysis based on 131 mother–baby dyads and 36 feto-pelvic variables. This obstetrical sample was compared with 20 australopithecine “dyads” generated from the combination of six pelvic reconstructions (three for Australopithecus afarensis, two for A. africanus, and one for A. sediba) and three fetal head size estimations. The obstetrical analysis revealed that dystocic births can be predicted by pelvic features such as an anteroposteriorly flattened pelvic inlet. Australopithecines shared these pelvic morphologies with humans and had eutocic birth only for infants of 110 g brain size or smaller, equaling a human-like neonatal/adult brain size ratio of 25–28%. Although birth mechanism cannot be deduced, the newborn/adult brain size ratio was likely more human-like than previously thought, suggesting that australopithecines were secondarily altricial to circumvent instances of obstructed labor and subsequently require a prolonged postnatal brain growth period, implying some aspects of life history pattern similar to modern humans.

@article{doi103390biology13060398,
    author = "Frémondière, P. and Haeusler, Martin and Thollon, Lionel and Webb, N. and Marchal, François",
    title = "Obstetrical Constraints and the Origin of Extended Postnatal Brain Maturation in Hominin Evolution",
    year = "2024",
    journal = "Biology",
    abstract = "Simple Summary The unique complexity of human childbirth is traditionally attributed to the opposing selection pressures of bipedal locomotion and large brains. Here, we explore this trade-off in Australopithecus with canonical discriminant analyses using different fetal head sizes. We reveal that the shape of the pelvis in Australopithecus led to a tight fit between the mother’s pelvis and the newborn head despite their relatively small brain sizes. To alleviate this obstetrical dilemma, australopithecines must have already given birth to secondarily altricial infants that were helpless at birth like those of extant humans. Cognitive development and some aspects of the modern life history pattern therefore likely originated prior to the appearance of the genus Homo. Abstract The origin of difficult birth is still a matter of debate in obstetrics. Recent studies hypothesized that early hominins already experienced obstructed labor even with reduced neonatal head sizes. The aim of this work is to test this hypothesis using an extant obstetrical sample with known delivery outcomes. Three delivery outcomes (i.e., instrument-assisted, Caesarean section, and vaginal birth) were evaluated using a discriminant analysis based on 131 mother–baby dyads and 36 feto-pelvic variables. This obstetrical sample was compared with 20 australopithecine “dyads” generated from the combination of six pelvic reconstructions (three for Australopithecus afarensis, two for A. africanus, and one for A. sediba) and three fetal head size estimations. The obstetrical analysis revealed that dystocic births can be predicted by pelvic features such as an anteroposteriorly flattened pelvic inlet. Australopithecines shared these pelvic morphologies with humans and had eutocic birth only for infants of 110 g brain size or smaller, equaling a human-like neonatal/adult brain size ratio of 25–28\%. Although birth mechanism cannot be deduced, the newborn/adult brain size ratio was likely more human-like than previously thought, suggesting that australopithecines were secondarily altricial to circumvent instances of obstructed labor and subsequently require a prolonged postnatal brain growth period, implying some aspects of life history pattern similar to modern humans.",
    url = "https://www.mdpi.com/2079-7737/13/6/398/pdf?version=1717139032",
    doi = "10.3390/biology13060398",
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: The dominant paradigm regarding human evolution since the split with Pan considers australopithecines as hominins, i.e., the closest relatives and/or direct ancestors of Homo . Historically, this paradigm started from the assumption that the Homo / Pan / Gorilla last common ancestor was a knuckle-walking ape that evolved into the fully upright (orthograde), obligate bipedal genus Homo , whereas Pan and Gorilla remained knuckle-walkers. Obligate terrestrial upright bipedalism, unique for our species, is an odd locomotor behaviour for a primate. Therefore, it had become generally accepted that a cooler and drier African climate had caused deforestation, which had forced our ancestors to develop upright bipedalism as an adaptation to living on open grassland savannah. This view, already held by Lamarck and Darwin, appeared most parsimonious in the almost complete absence of fossils. The discovery in the 20th century of australopithecine fossils, bipedal apes with small brains, in open country in southern and eastern Africa corroborated the savannah paradigm. Therefore, australopithecines are considered hominins. However, it is now recognized that most australopithecines instead lived in a mosaic of forests, grasslands and wetlands, and better knowledge of their fossils clearly indicates that they possessed several climbing adaptations. Moreover, none of the extinct ape species older than Australopithecus and Paranthropus for which postcranial remains have been described (e.g., Morotopithecus, Sahelanthropus , Orrorin , Ardipithecus ) were knuckle-walking. On the other hand, upright posture/gait is already present to different degrees even in Miocene apes. Moreover, the notion that hominoid orthogrady is a primitive characteristic is corroborated by the growing consensus that knuckle-walking is not a primitive trait but has evolved in parallel, independently in both Pan and Gorilla . Consequently, it is possible that australopithecines are not transitional between a semi-erect ancestor and upright bipedal humans, but to the contrary, are intermediate between a more upright ancestor and extant semi-erect African apes. In summary, hypotheses that attempt to explain how a semi-erect Homo / Pan last common ancestor transitioned into the bipedal australopithecines as an adaptation to life on the savannah appear to be ill-conceived and moreover seem to have been superfluous from the very start. We review the numerous similarities between australopithecines and extant African apes, suggesting that they are possibly not hominins and therefore not our direct ancestors. We suggest that we may have been barking up the wrong ancestral tree, for almost a century.

@article{doi1035534natanthropol202310007,
    author = "Vaneechoutte, Mario and Mansfield, Frances and Munro, S. and Verhaegen, M.",
    title = "Have We Been Barking up the Wrong Ancestral Tree? Australopithecines Are Probably Not Our Ancestors",
    year = "2024",
    journal = "Nature Anthropology",
    abstract = ": The dominant paradigm regarding human evolution since the split with Pan considers australopithecines as hominins, i.e., the closest relatives and/or direct ancestors of Homo . Historically, this paradigm started from the assumption that the Homo / Pan / Gorilla last common ancestor was a knuckle-walking ape that evolved into the fully upright (orthograde), obligate bipedal genus Homo , whereas Pan and Gorilla remained knuckle-walkers. Obligate terrestrial upright bipedalism, unique for our species, is an odd locomotor behaviour for a primate. Therefore, it had become generally accepted that a cooler and drier African climate had caused deforestation, which had forced our ancestors to develop upright bipedalism as an adaptation to living on open grassland savannah. This view, already held by Lamarck and Darwin, appeared most parsimonious in the almost complete absence of fossils. The discovery in the 20th century of australopithecine fossils, bipedal apes with small brains, in open country in southern and eastern Africa corroborated the savannah paradigm. Therefore, australopithecines are considered hominins. However, it is now recognized that most australopithecines instead lived in a mosaic of forests, grasslands and wetlands, and better knowledge of their fossils clearly indicates that they possessed several climbing adaptations. Moreover, none of the extinct ape species older than Australopithecus and Paranthropus for which postcranial remains have been described (e.g., Morotopithecus, Sahelanthropus , Orrorin , Ardipithecus ) were knuckle-walking. On the other hand, upright posture/gait is already present to different degrees even in Miocene apes. Moreover, the notion that hominoid orthogrady is a primitive characteristic is corroborated by the growing consensus that knuckle-walking is not a primitive trait but has evolved in parallel, independently in both Pan and Gorilla . Consequently, it is possible that australopithecines are not transitional between a semi-erect ancestor and upright bipedal humans, but to the contrary, are intermediate between a more upright ancestor and extant semi-erect African apes. In summary, hypotheses that attempt to explain how a semi-erect Homo / Pan last common ancestor transitioned into the bipedal australopithecines as an adaptation to life on the savannah appear to be ill-conceived and moreover seem to have been superfluous from the very start. We review the numerous similarities between australopithecines and extant African apes, suggesting that they are possibly not hominins and therefore not our direct ancestors. We suggest that we may have been barking up the wrong ancestral tree, for almost a century.",
    url = "https://www.sciepublish.com/index/journals/view\_full\_text/id/94",
    doi = "10.35534/natanthropol.2023.10007",
    is_oa = "true",
    number = "1",
    pages = "10007-10007",
    semanticscholar_citation_count = "4",
    semanticscholar_id = "c37fb5b070d8d4c5c8ea7f9887cc932816650f09",
    volume = "2"
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@incollection{carlson2025the,
    author = "Carlson, Kristian J. and Cazenave, Marine",
    title = "The Australopithecines",
    year = "2025",
    booktitle = "Encyclopedia of Quaternary Science",
    url = "https://doi.org/10.1016/b978-0-323-99931-1.00259-2",
    doi = "10.1016/b978-0-323-99931-1.00259-2",
    pages = "64-71"
}

The emergence of bipedal locomotion during human evolution has considerably reshaped the hominin pelvis, which also impacted the pelvic floor musculature. Among early hominins, australopithecines have an anteroposteriorly narrow, transversely wide bony pelvis. This study investigates whether this particular shape of the birth canal weakens the pelvic floor during childbirth in these hominins and if the pelvic floor contributes to rotational birth. As such, we explored the stress values at the pelvic floor that occur during the descent of the fetal head, using 3D models of extant humans based on the reconstruction of pelvic-fetal dyads from hospital records with known birth outcomes. We then compared this to 3D models based on pelvic reconstructions of A.L. 288-1 (Australopithecus afarensis), Sts 14 (A. africanus), and MH2 (A. sediba) using a 110 g neonatal brain weight. The early hominin pelvic floor was reconstructed by warping the pelvis and pelvic floor extracted from an MRI of a modern adult woman to the australopithecine pelvic morphology. Our results suggest that the range of stress values on the pelvic floor is comparable between humans (5.3-10.5 MPa) and australopithecines (4.9-10.7 MPa), suggesting that their females may have been exposed to a similarly high risk of perineal laceration during vaginal delivery as modern humans. None of the four australopithecine simulations, and only one out of two modern human simulations, showed an internal rotation of the fetal head into an occiput anterior orientation, suggesting this movement is particularly complex and involves influences beyond just the levator ani musculature.

@article{doi101002ar70173,
    author = "Frémondière, Pierre and Thollon, Lionel and Webb, Nicole M and Haeusler, Martin and Marchal, François",
    title = "A finite element study of soft-tissue deformation during birth in australopithecines: Assessing pelvic floor stress and fetal head rotation in early hominins.",
    year = "2026",
    journal = "Anatomical record (Hoboken, N.J.: 2007)",
    abstract = "The emergence of bipedal locomotion during human evolution has considerably reshaped the hominin pelvis, which also impacted the pelvic floor musculature. Among early hominins, australopithecines have an anteroposteriorly narrow, transversely wide bony pelvis. This study investigates whether this particular shape of the birth canal weakens the pelvic floor during childbirth in these hominins and if the pelvic floor contributes to rotational birth. As such, we explored the stress values at the pelvic floor that occur during the descent of the fetal head, using 3D models of extant humans based on the reconstruction of pelvic-fetal dyads from hospital records with known birth outcomes. We then compared this to 3D models based on pelvic reconstructions of A.L. 288-1 (Australopithecus afarensis), Sts 14 (A. africanus), and MH2 (A. sediba) using a 110 g neonatal brain weight. The early hominin pelvic floor was reconstructed by warping the pelvis and pelvic floor extracted from an MRI of a modern adult woman to the australopithecine pelvic morphology. Our results suggest that the range of stress values on the pelvic floor is comparable between humans (5.3-10.5 MPa) and australopithecines (4.9-10.7 MPa), suggesting that their females may have been exposed to a similarly high risk of perineal laceration during vaginal delivery as modern humans. None of the four australopithecine simulations, and only one out of two modern human simulations, showed an internal rotation of the fetal head into an occiput anterior orientation, suggesting this movement is particularly complex and involves influences beyond just the levator ani musculature.",
    url = "https://pubmed.ncbi.nlm.nih.gov/41804182/",
    doi = "10.1002/ar.70173",
    openalex = "W7134839956",
    pmid = "41804182",
    references = "doi101001jama201818315, doi101001jama300111311, doi101006jhev19951063, doi101007s0019201012150, doi101016jogc201510008, doi101016s0047248486800525, doi101126science1175831, doi101126science1202521, doi101159000156111, doi101186s12889023169013"
}

BACKGROUND In hominins, the reduction of prognathism during craniofacial evolution was a significant derived trait differentiating Homo from earlier hominins and other apes and might have contributed significantly to calvarial expansion and encephalization. Gnathic remains of Australopithecus africanus, A. robustus, Homo habilis, and H. erectus from the Plio-Pleistocene boundary 5.3-2.6 MYA were studied for evidence of alveolar bone (AB) loss indicative of periodontal disease(s). AB loss may provide critical insights into craniofacial evolution and the divergence of Homo from the Australopithecines. AB loss in Plio-Pleistocene gnathic remains provides the fossilized hard evidence of the antiquity of periodontal diseases, the first recognized diseases in hominins' evolution. METHODS Seventy-one gnathic remains of Australopithecines and Homo species from Ditsong Museum of Natural History, Pretoria, and the School of Anatomy of the University of the Witwatersrand, Johannesburg, were examined using scanning electron microscopy (SEM) and macrophotography. Specimens were scanned at the microfocus X-ray tomography laboratory (MIXRAD) at Necsa, Pretoria, optimizing on highest spatial resolution and image contrast. Linear distances from the enamel-dentine junction (EDJ) to the remaining AB crest were also measured. RESULTS Morphometric analyses showed that there is progressive AB loss as hominins speciated from Australopithecines to Homo. Homo remains showed statistically significant variation when analysing the linear distance between the EDJ and the remaining AB when compared with both Australopithecine taxa. AB loss was confirmed by microfocus X-ray tomography and, in Homo species only, showed a vertical pattern of bone loss with crateriform lesions and furcation defects. SEM and microfocus X-ray tomography, macrophotography, and linear measurements from the EDJ to the remaining alveolar bone showed that Homo had greater alveolar bone loss with intrabony defects and craters when compared with Australopithecines' taxa. There were no significant differences between the 2 Australopithecine species examined. CONCLUSIONS The presented data show that Homo species developed significant AB loss. The data propose that random mutations of genes controlling odontometric values selected for a reduction of the size of the crowns during hominins' evolution. Smaller crowns ultimately resulted in weaker masticatory forces yet allowing masticatory function and thus survival in the presence of AB loss. Together with the speciation of smaller crowns, with reduction of masticatory muscle mass and thus masticatory forces, there was a reduction of prognathism leading to calvarial expansion with subsequent encephalization, speciating the Homo clade and later, the emergence of Homo sapiens.

@article{doi101097scs0000000000012390,
    author = "Ripamonti, U. and Roden, Laura C and Hoffman, J.",
    title = "Craniofacial Evolution and Alveolar Bone Loss: A Lesson From Hominins.",
    year = "2026",
    journal = "The Journal of craniofacial surgery",
    abstract = "BACKGROUND In hominins, the reduction of prognathism during craniofacial evolution was a significant derived trait differentiating Homo from earlier hominins and other apes and might have contributed significantly to calvarial expansion and encephalization. Gnathic remains of Australopithecus africanus, A. robustus, Homo habilis, and H. erectus from the Plio-Pleistocene boundary 5.3-2.6 MYA were studied for evidence of alveolar bone (AB) loss indicative of periodontal disease(s). AB loss may provide critical insights into craniofacial evolution and the divergence of Homo from the Australopithecines. AB loss in Plio-Pleistocene gnathic remains provides the fossilized hard evidence of the antiquity of periodontal diseases, the first recognized diseases in hominins' evolution. METHODS Seventy-one gnathic remains of Australopithecines and Homo species from Ditsong Museum of Natural History, Pretoria, and the School of Anatomy of the University of the Witwatersrand, Johannesburg, were examined using scanning electron microscopy (SEM) and macrophotography. Specimens were scanned at the microfocus X-ray tomography laboratory (MIXRAD) at Necsa, Pretoria, optimizing on highest spatial resolution and image contrast. Linear distances from the enamel-dentine junction (EDJ) to the remaining AB crest were also measured. RESULTS Morphometric analyses showed that there is progressive AB loss as hominins speciated from Australopithecines to Homo. Homo remains showed statistically significant variation when analysing the linear distance between the EDJ and the remaining AB when compared with both Australopithecine taxa. AB loss was confirmed by microfocus X-ray tomography and, in Homo species only, showed a vertical pattern of bone loss with crateriform lesions and furcation defects. SEM and microfocus X-ray tomography, macrophotography, and linear measurements from the EDJ to the remaining alveolar bone showed that Homo had greater alveolar bone loss with intrabony defects and craters when compared with Australopithecines' taxa. There were no significant differences between the 2 Australopithecine species examined. CONCLUSIONS The presented data show that Homo species developed significant AB loss. The data propose that random mutations of genes controlling odontometric values selected for a reduction of the size of the crowns during hominins' evolution. Smaller crowns ultimately resulted in weaker masticatory forces yet allowing masticatory function and thus survival in the presence of AB loss. Together with the speciation of smaller crowns, with reduction of masticatory muscle mass and thus masticatory forces, there was a reduction of prognathism leading to calvarial expansion with subsequent encephalization, speciating the Homo clade and later, the emergence of Homo sapiens.",
    url = "https://www.semanticscholar.org/paper/682f261c840e3e92fd5663a2c6d38603508446ba",
    doi = "10.1097/SCS.0000000000012390",
    is_oa = "true",
    semanticscholar_id = "682f261c840e3e92fd5663a2c6d38603508446ba"
}