The Anterior Dentition Of Sivapithecus-parvada, With Comments On The Phylogenetic Significance Of Incisor Heteromorphy In Hominoidea
Anthropology; clade; dentition; east-africa; evolution; Evolutionary Biology; hominids; hominoid phylogenetics; incisors; kenya; middle miocene; miocene hominoid; orangutan; origin; pakistan; pongo; sivapithecus; specimens
A premaxillary fragment of Sivapithecus parvada preserving the germs of the right central and lateral incisors is described. The specimen was recovered in situ during excavation at locality Y311 in the upper Nagri Formation (ca. 9.2 m.y.a.) of the Siwalik Sequence, Potwar Plateau, Pakistan. The central incisor is approximately 35% larger than the next largest Sivapithecus incisor, in keeping with the very large size of S. parvada compared to other Sivapithecus species, and is exceptionally long mesiodistally in relation to its breadth. It is also morphologically distinct, having a sharply angled distal margin and a distinct lingual tubercle. However, previous descriptions of Sivapithecus upper central incisors as having a continuous lingual shelf are in some cases erroneous and ignore the morphological variation present in the sample. In several features of anterior tooth size, morphology and proportionality, S. parvada resembles Pongo more than do other species of Sivapithecus. The I1/I2 length ratio of the new specimen is 2.12, the largest size disparity reported for any fossil catarrhine, and greater than any single value in a large sample of Pongo pygmaeus. Very great size disparity between upper central and lateral incisors is widely considered to be a synapomorphy of the orang-utan lineage. We conclude, however, that descriptions of upper incisor size heteromorphy in Pongo have in general been exaggerated and have failed to recognize substantial differences in this character between Bornean and Sumatran orang-utans. We further conclude, based on examination of a variety of Miocene hominoids and other Miocene catarrhine primates, that the character of I1/I2 proportionality has little if any phylogenetic utility within Hominoidea.
Kelley J; Anwar M; McCollum M A; Ward S C
Journal of Human Evolution
1995
1995-06
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1006/jhev.1995.1039" target="_blank" rel="noreferrer noopener">10.1006/jhev.1995.1039</a>
South Turkwel: A new Pliocene hominid site in Kenya
1974-1977 collections; Anthropology; australopithecus-afarensis; ethiopia; evolution; Evolutionary Biology; functional-morphology; hadar formation; hand; hand bones; hominids; Kenya; koobi fora region; metacarpal; olduvai gorge; Pliocene; South Turkwel
New fossils discovered south of the Turkwel River in northern Kenya include an associated metacarpal, capitate, hamate, lunate, pedal phalanx, mandibular fragment, and teeth. These fossils probably date to around 3.5 m.y.a. Faunal information suggests that the environment at South Turkwel was predominantly bushland. The mandibular and dental remains are fragmentary, but the postcranial fossils are informative. Comparisons with Australopithecus, modern human, chimpanzee and gorilla hand bones suggest that the Turkwel hominid was most like Australopithecus afarensis and A. africanus. Carpometacarpal articulations are intermediate between those of modern humans and African apes, suggesting enhanced gripping capabilities compared with extant apes. The hamulus was strikingly large, similar in proportion only to Neandertals and some gorillas, suggesting the presence of powerful forearms and hands. There are no indicators of adaptations to knuckle-walking or suspensory locomotion in the hand, and the pedal phalanx suggests that this hominid was habitually bipedal. (C) 1999 Academic Press.
Ward C V; Leakey M G; Brown B; Brown F; Harris J; Walker A
Journal of Human Evolution
1999
1999-01
Journal Article
<a href="http://doi.org/10.1006/jhev.1998.0262" target="_blank" rel="noreferrer noopener">10.1006/jhev.1998.0262</a>
EVOLUTIONARY HISTORY OF THE ROBUST AUSTRALOPITHECINES - GRINE,FE
Anthropology; boisei; brain; east-africa; Evolutionary Biology; growth; hominids; Homo; Kenya; miocene; neogene
Ward S C
Journal of Human Evolution
1991
1991-12
Journal Article
<a href="http://doi.org/10.1016/0047-2484(91)90097-f" target="_blank" rel="noreferrer noopener">10.1016/0047-2484(91)90097-f</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>