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The functional anatomy of the forelimb has played a critical role in reconstructing locomotor and postural adaptations of fossil anthropoids, including hominins. This study examined the functional anatomy of the midcarpal joint and wrist ranges of motion in extant hominoids and terrestrial cercopithecines to investigate ways that knuckle-walkers are similar to, and distinct from, other terrestrial catarrhines. New data on maximum ranges of motion in Pan, Hylobates, Papio, and Erythrocebus support the conclusion that Asian apes have unusually mobile wrist joints as adaptations for suspension and/or climbing activities, and that African ape wrists have limited ranges of extension as an adaptation to knuckle-walking. Results provide some support to hypotheses about aspects of midcarpal morphology being functionally related to limiting wrist extension in the knuckle-walking African apes. The depth of the concavity on the scaphoid/centrale facet of the capitate, the distal extent of articular surfaces, and dorsal ridge development appear to distinguish knuckle-walkers. Although variability exists in any single characteristic, the total morphological pattern is fairly distinct in African apes. The likely role of the capitate-scaphoid joint in limiting extension during knuckle-walking supports the hypothesis that early ontogenetic fusion of the os centrale to the scaphoid is a knuckle-walking adaptation. African apes and the terrestrial cercopithecoids have significantly broader midcarpal joints compared to Asian apes, supporting the hypotheses that the morphologies in the former taxa represent adaptations to pronograde weight support, and in the latter are adaptations for increased mobility. The broad midcarpal morphology of the early hominin (∼3.5 Ma Australopithecus) KNM-WT 22944 supports evidence that hominins evolved from an ancestor adapted to knuckle-walking and climbing, rather than a climbing ancestor with a locomotor repertoire that lacked a terrestrial component. [ABSTRACT FROM AUTHOR]

A provisional idea is presented that the origin of bipedality preceded the great ape-human divergence, i.e., the hominoid ancestral to the humans and African apes was a “generalized biped.” The idea, however, is based on a series of assumptions which are largely speculative. While these assumptions have to be validated in the light of forthcoming findings, several points specifically should be clarified. First, could the supposed hyper-muscularization of Late Miocene hominoids, associated with arboreal living and up-sizing, account for the emergence of generalized bipeds on the ground? Second, could the generalized bipeds survive ground living in woodland environments? Third, did the return arboreality in the great ape lineage really occur? Fourth, what caused the human lineage to expand into open habitats? [ABSTRACT FROM AUTHOR]

The discovery of 6 Ma bipedal Orrorin in a heavy woodland to forest paleoenvironmental setting indicates that bipedalism most likely evolved in relatively closed vegetation formations of the kind that are common in Soudanian, Somali-Masai, and Zambezian centers of endemism and in the transition zones between these centers and the Guineo-Congolian center of endemism. It is much less likely that it evolved in savanna settings, such as are typical of Sahelian and Kalahari centers of endemism or even more open vegetation formations. In short, it was not only environmental change that drove the origin of bipedalism as has been thought by many researchers for the past century or more, but also a change in ecology. Of course, open environments had to be present for them to be occupied, but their formation did not immediately result in their occupation by hominoids. Indeed it took tens of millions of years before an ape lineage evolved the prerequisite adaptations for such a development to take place. These adapatations were initially locomotor in nature, but later incorporated dietary (dental and digestive tract modifications), the storage of reserves of fat within the body, and behavioral changes, all of which resulted in greater eurytopy. It is considered most likely that bipedalism evolved in forested to well-wooded environments, and only later did bipedal hominids venture into more open country. Thus bipedalism was a development which subsequently enabled hominids to invade open country. It was not invasion of open country that led to bipedalism as so often thought. [ABSTRACT FROM AUTHOR]

The Late Miocene mammalian faunas of sub-Saharan Africa, especially the Namurungule Fauna, indicate a close similarity with the Turolian faunas from sub-Paratethys and North Africa. The Miocene mammalian faunas of sub-Saharan Africa show resemblances with late Vallesian to Turolian ones of North Africa, sub-Paratethys, Southwest and Central Europe faunas. Mammalian assemblages of sub-Saharan Africa changed drastically during the Middle Miocene (Astaracian). This faunal turnover is marked by an increase of open country taxa. It indicates the spreading of the warm and arid environment (savannitization) in the Middle to Late Miocene sub-Saharan Africa. Furthermore, the Pleistocene and extant taxa evolved from the Late Miocene sub-Saharan African faunas. The Namurungule Fauna is the pioneer of the modern sub-Saharan mammalian fauna of savanna environments. The Middle Miocene event of mammalian fauna and environmental change in sub-Saharan Africa played an important role in the Late Miocene evolution of hominids. [ABSTRACT FROM AUTHOR]

As possibly the earliest higher primate to eschew the trees and descend to the ground, Victoriapithecus offers several important lessons that may have implications for understanding our own ancestry. First, while paleoenvironment obviously constrains paleoecology, it should not be equated with a species’ paleoecology. Although there is a definite correlate between substrate preference and locomotor mode, evidence from Victoriapithecus suggests there is no a priori relationship between locomotor mode and paleoenvironment; that is, wooded or forested environs do not preclude terrestrial behaviors. Second, body size is likely to be a consequence of the shift to terrestriality, rather than a cause for the shift. The small body size of Victoriapithecus and other early cercopithecoids probably proved a liability with the advent of widespread savannah habitats. Size increases within the hominid lineage show a similar trajectory, as hominids gradually adapted to, and then came to dominate, the grassland environment. Finally, the adoption of terrestriality has traditionally been linked with the spread of grassland habitats and the shift to bipedalism. Victoriapithecus, however, provides proof that terrestrial behavior among the Catarrhini is instead first seen in a cercopithecoid that lived 12–20 million years ago in a wooded environment. As similar environmental contexts are now postulated for some of the very earliest hominids, the adoption of terrestriality and the eventual acquisition of bipedalism must now be linked to a very different set of adaptive correlates. The presence of terrestrial behaviors in African apes and in the hominid lineage, as well as possible evidence of knuckle-walking in both some Miocene hominoids and in our own ancestry, also argue strongly for a reconsideration of the role of terrestriality in our heritage, its timing, and in its correlates of diet and environment. [ABSTRACT FROM AUTHOR]

Bonobos range over the area between the Congo-Lualaba River and the Kasai-Sankuru River in the Democratic Republic of the Congo (DRC; Kano 1984). Kano et al. (1996) stated that bonobos are more or less continuously distributed throughout the northern part of their range, which is covered by tropical rain forest, and are distributed fragmentarily in the southern part, where the vegetation is a mosaic of forest and grassland. Kano (1992) estimated that the population of bonobos in the whole of the DRC to be ca. 50,000 in 1973. The number has decreased after several wars; however, the current population size is unknown. [ABSTRACT FROM AUTHOR]

Have you been to a football game lately? Think of the last time you were in an arena that seated fifty or even a hundred thousand people. That many people can make a lot of noise, but of course only represent a tiny piece of humanity today. If we could convince all the bonobos in the world to attend such a game, you could not come close to filling even the smallest professional football stadium. Our closest living relative is slipping off the precipice; their extinction in our own lifetime is a real possibility. [ABSTRACT FROM AUTHOR]