Locomotion, posture, and the foramen magnum in primates: Reliability of indices and insights into hominin bipedalism

Landi, Federica; Profico, Antonio; Veneziano, Alessio; Groote, Isabelle De; Manzi, Giorgio

doi:10.1002/ajp.23170

Cited by 7 publications

(4 citation statements)

References 77 publications

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“…Similarly, Gorilla and Hylobatidae frequently cluster together, as shown in Figure 4. Two additional factors hypothesized to explain differences in facial suture patterning are locomotor style [Gebo, 1989;Landi et al, 2020] and diet [Chapman and Chapman, 1990;Fish and Lockwood, 2003;Chapman and Rothman, 2009;De-Casien et al, 2017]. Our data do not support these as driving factors in facial suture fusion patterns since Gorilla and Hylobatidae consistently cluster together but do not share the same locomotor style or dietary regimes.…”

Section: Discussioncontrasting

confidence: 66%

Variation in Ontogenetic Facial Suture Fusion Patterns in Catarrhines

et al. 2021

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Timing of craniofacial suture fusion is important for the determination of demographics and primate ontogeny. There has been much work concerning the timing of fusion of calvarial sutures over the last century, but little comprehensive work focusing on facial sutures. Here we assess the relationships of facial suture fusion across ontogeny among select catarrhines. Fusion timing patterns for 5 facial sutures were examined in 1,599 crania of Homo, Pan, Gorilla, Pongo, Hylobatidae, Papio, and Macaca. Calvarial volume (early ontogeny) and dental eruption (late ontogeny) were used as indicators of stage of development. General linear models, test for homogeneity of slopes, and ANOVA were used to determine differences in timing of fusion by taxon. For calvarial volume, taxonomic groups segregated by regression slopes, with models for Homo indicating sutural fusion throughout ontogeny, Pongo, Macaca, and Papio representing earlier and more complete suture fusion, and Pan, Gorilla, and Hylobatidae indicating very early facial suture fusion. Similar patterns are observed when dental eruption is used for developmental staging. Only Gorilla and Hylobatidae are observed to, generally, fuse all facial suture sites in adulthood. Finally, Homo appears to be unique in its delay and patency of sutures into late ontogeny. The taxonomic patterns of facial suture closure identified in this study likely reflect important evolutionary shifts in facial growth and development in catarrhines.

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Section: Discussioncontrasting

confidence: 66%

Variation in Ontogenetic Facial Suture Fusion Patterns in Catarrhines

et al. 2021

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“…The difficulties in linking foramen magnum indices to the degree of orthogrady have been outlined in detail recently [113]. Locomotor adaptations, for example, may not be the sole factors responsible for the anteroposterior position of the foramen magnum in primates.…”

Section: Position and Orientation Of The Foramen Magnummentioning

confidence: 99%

Have We Been Barking up the Wrong Ancestral Tree? Australopithecines Are Probably Not Our Ancestors

Vaneechoutte,

Mansfield,

Munro

et al. 2024

Nature Anthropology

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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.

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“…Filler (2007a, p. 5) introduced “diagonograde” as a “non‐upright…body carried at about 45 degrees rather than upright orthograde or horizontal pronograde” and “partially horizontal body posture” (Filler, 2007a, p. 19). Anquetin et al (2007, p. 577) focused on relative limb lengths in quadrupeds and coined “clinograde” for when “the forelimbs are very elongated whereas the hindlimbs are quite shortened… like gorillas,” a term picked up and elaborated on by Landi et al (2020, p. 5): “In clinograde species, the forelimbs are elongated and the hindlimbs are flexed, the trunk is angled in relation to the ground and forms a triangle with the limbs.” The aforementioned usages of these terms refer to the orientation of the axial skeleton or some aspect of it relative to hypothetical vertical and horizontal dimensions of an environment, which differs substantially within and between quadrupeds and bipeds (Figure 2). Such newly introduced terms neither fundamentally correspond to an animal's mode of progression through its environment nor necessarily to how a body plan has been shaped over its evolutionary history.…”

Section: The Grady Bunchmentioning

confidence: 99%