The taxonomic status of the Chemeron temporal (KNM-BC 1)
Anthropology; australopithecus-africanus; Chemeron temporal; earliest homo; Evolutionary Biology; extant; fossil hominids; hadar formation; hominoids; Homo; lake turkana; meningeal vascular patterns; plio-pleistocene hominids; south-africa; swartkrans formation; temporal bone
Temporal bone morphology, as part of the basicranium, is commonly used in systematic evaluation of early hominid fossils. When an isolated right temporal bone, KNM-BC 1 (the Chemeron temporal) was discovered in the Baringo Basin, Kenya, Tobias (1967a, Nature 215, 476-480), citing ambiguity of characters, hesitated to place the specimen generically, attributing the fossil only to Hominidae gen. et sp. indet. Since that discovery, the early hominid sample has grown considerably and comparisons with this expanded dataset led Hill et al. (1992a, Nature 355, 719-722) to revise the placement of KNM-BC 1 including it within the genus Homo. This revision was possible due to the increased number of hominid fossil specimens from the late Pliocene/early Pleistocene, most notably members of the genus Homo. A thorough investigation into the utility of the temporal bone in hominid systematics shows that many features, as currently used. in the literature, demonstrate high levels of variation thus questioning their phyletic valence. It is shown, however, that the temporal bone still contains useful systematic information. A detailed anatomical description of KNM-BC 1 is provided and, when discussed in the context of temporal bone features provided, affirms the conclusion of Hill et al. (1992a) and places the fossil within the genus Homo. (C) 2002 Academic Press.
Sherwood R J; Ward S C; Hill A
Journal of Human Evolution
2002
2002-01
Journal Article
<a href="http://doi.org/10.1006/jhev.2000.0409" target="_blank" rel="noreferrer noopener">10.1006/jhev.2000.0409</a>
Foramen magnum position in bipedal mammals
Anthropology; australopithecus-africanus; basicranial flexion; Basicranium; condyles; Convergent; cranial base; energetic cost; evolution; Evolutionary Biology; hominids; Hominin; Locomotion; occipital; Orthogrady; pliopleistocene; postnatal-development; relative brain size; sahelanthropus-tchadensis; south-africa; Trunk posture
The anterior position of the human foramen magnum is often explained as an adaptation for maintaining balance of the head atop the cervical vertebral column during bipedalism and the assumption of orthograde trunk postures. Accordingly, the relative placement of the foramen magnum on the basicranium has been used to infer bipedal locomotion and hominin status for a number of Mio-Pliocene fossil taxa. Nonetheless, previous studies have struggled to validate the functional link between foramen magnum position and bipedal locomotion. Here, we test the hypothesis that an anteriorly positioned foramen magnum is related to bipedalism through a comparison of basicranial anatomy between bipeds and quadrupeds from three mammalian clades: marsupials, rodents and primates. Additionally, we examine whether strepsirrhine primates that habitually assume orthograde trunk postures exhibit more anteriorly positioned foramina magna compared with non-orthograde strepsirrhines. Our comparative data reveal that bipedal marsupials and rodents have foramina magna that are more anteriorly located than those of quadrupedal close relatives. The foramen magnum is also situated more anteriorly in orthograde strepsirrhines than in pronograde or antipronograde strepsirrhines. Among the primates sampled, humans exhibit the most anteriorly positioned foramina magna. The results of this analysis support the utility of foramen magnum position as an indicator of bipedal locomotion in fossil hominins. (C) 2013 Elsevier Ltd. All rights reserved.
Russo G A; Kirk E C
Journal of Human Evolution
2013
2013-11
Journal Article
<a href="http://doi.org/10.1016/j.jhevol.2013.07.007" target="_blank" rel="noreferrer noopener">10.1016/j.jhevol.2013.07.007</a>