The Experts below are selected from a list of 1989 Experts worldwide ranked by ideXlab platform
Holly B Smith - One of the best experts on this subject based on the ideXlab platform.
-
dental development and the evolution of life history in hominidae
American Journal of Physical Anthropology, 1991Co-Authors: Holly B SmithAbstract:Development of the dentition is critically integrated into the life cycle in living mammals. Recent work on dental development has given rise to three separate lines of evidence on the evolution of human growth and aging; these three, based on several independent studies, are reviewed and inte- grated here. First, comparative study of living primate species demonstrates that measures of development (e.g., age of emergence of the first permanent molar) are highly correlated with the morphological attributes brain and body weight (as highly as r = 0.98, N = 21 species). These data predict that small-bodied, small-brained Australopithecus erupted M, at 3-3.5 years and possessed a life span comparable to that of a chimpanzee. Second, chronologi- cal age at death for three Australopithecines who died at or near emergence of MI is now estimated as -3.25 years based on incremental lines in teeth; this differs substantially from expectations based on human growth schedules (5.5-6 years). Third, developmental sequences (assessed by the coefficient of variation of human dental age) observed in gracile Australopithecus and great apes diverge from those of humans to a comparable degree; sequences become more like modern humans after the appearance of the genus Homo. These three lines of evidence agree that the unique rate and pattern of human life history did not exist at the australopithecine stage of human evolution. It is proposed that the life history of early Homo matched no living model precisely and that growth and aging evolved substantially in the Hominidae during the last 2 million years.
Carel P. Van Schaik - One of the best experts on this subject based on the ideXlab platform.
-
Interpreting hominid behavior on the basis of sexual dimorphism
Journal of Human Evolution, 1997Co-Authors: J. Michael Plavcan, Carel P. Van SchaikAbstract:Abstract Numerous studies use estimates of sexual dimorphism in canine tooth size and body weight to support speculation about the behavior of Australopithecines. However, the range of mating systems inferred for Australopithecines encompasses virtually the entire spectrum of mating systems seen among extant anthropoid primates, from monogamy to polygyny characterized by intense male–male competition. This variety of opinion can be attributed partly to the unusual combination of high body size dimorphism and reduced canine dimorphism in Australopithecines. Here we provide a joint comparison of recent models for the behavioral correlates of both canine dimorphism and body size dimorphism, and apply this to published estimates of dimorphism in body size and canine tooth size in hominids. Among extant species, body weight dimorphism and canine dimorphism are strongly correlated with estimates of intrasexual competition. Canine crown height dimorphism provides the best discrimination between taxa that show high degrees of male–male competition, and those that do not. Relative male maxillary canine tooth size offers additional evidence about male–male competition. On the other hand, canine occlusal dimorphism offers little discrimination among species of different male–male competition levels. Estimates of canine dimorphism, relative canine size, and body weight dimorphism in Australopithecines provide little definitive information about male–male competition or mating systems. Dimorphism ofAustralopithecus africanusandAustralopithecus robustuscan be reconciled with a mating system characterized by low-intensity male–male competition. The pattern of dimorphism and relative canine size inAustralopithecus afarensisandA. robustusprovides contradictory evidence about mating systems and male–male competition. We review a number of hypotheses that may explain the unusual pattern of dimorphism ofA. afarensisandAustralopithecus boiseibut non-satisfactorily resolves the problem given current data.
Michael W. Vannier - One of the best experts on this subject based on the ideXlab platform.
-
Dental development in South African Australopithecines. Part I: Problems of pattern and chronology
American Journal of Physical Anthropology, 1991Co-Authors: Glenn C. Conroy, Michael W. VannierAbstract:It is well known that humans take about twice as long as apes to mature. The traditional view that such delayed maturation was already present in Australopithecines has been called into question during the past several years. We have approached this problem by looking at patterns of dental development in gracile and robust Australopithecines from South Africa and comparing them to patterns found in extant humans and apes. We have employed both 2 and 3 dimensional computed tomography in our research. The dental growth patterns in these two australopithecine morphs differ, particularly in M1/I1 development. The robust Australopithecines are more humanlike and the gracile Australopithecines more apelike in this feature (“humanlike” and “apelike” are not used in any taxonomic sense). Pattern and chronology of dental development must be considered separately. Several major problem areas for future research are identified, most of which revolve around the issue of intra- versus interspecific variation.
Robert S. Corruccini - One of the best experts on this subject based on the ideXlab platform.
-
Multivariate analysis of Gigantopithecus mandibles
American journal of physical anthropology, 2005Co-Authors: Robert S. CorrucciniAbstract:Multivariate analysis of measurements of the teeth and mandibles of Gigantopithecus species has been conducted, using several methods. Results indicate Gigantopithecus is an aberrant form, less related to Australopithecines and gorillas than the latter are to each other. Gracile and robust Australopithecines differ considerably more than do male and female gorillas.
Bernard Wood - One of the best experts on this subject based on the ideXlab platform.
-
homoplasy and earlyhomo an analysis of the evolutionary relationships ofh habilissensu stricto andh rudolfensis
Journal of Human Evolution, 1996Co-Authors: Daniel E Lieberman, Bernard Wood, David PilbeamAbstract:Abstract Dividing the fossils usually assigned to the taxonHomo habilis sensu latointo two species (as most researchers now accept) necessitates a re-examination of their evolutionary relationships. A cladistic analysis of 48 of the most commonly-used cranial characters from recent studies of Pliocene hominid phylogeny and which distinguish two taxa withinH. habilis sensu latosuggests that these fossils have different evolutionary affinities. One taxon,H. habilis sensu stricto, is represented by KNM-ER 1813 and the fossils from Olduvai Gorge, and is most likely a sister group ofH. erectus. The other taxon,H. rudolfensis, is represented by KNM-ER 1470, and shares many derived characters with the Australopithecines. A close analysis of the developmental basis of these characters suggests that many of the australopithecine similarities ofH. rudolfensisare likely to be homologies rather than homoplasies.
-
Taxonomic and geographic diversity in robust Australopithecines and other African Plio-Pleistocene larger mammals
Journal of Human Evolution, 1993Co-Authors: Alan Turner, Bernard WoodAbstract:Abstract There is considerable evidence to support the allocation of all eastern and southern African robust Australopithecines to the genus Paranthropus, but the case for a polyphyletic origin is nol totally refuted. In order to assess the argument for convergence in the face of conflicting signals from the hominid remains, we have turned to evidence from patterns of geographic distribution in other monophyletic groups of larger African Plio-Pleistocene mammals. These distributions point to considerable contact between eastern and southern Africa in addition to the existence of regional representatives of other monophyletic groups. The suggestion that robust australopithecine monophyly is not an exotic interpretation is consistent with the evolutionary history of several other mammalian groups.
