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Dental Morphology (dental + morphology)
Selected AbstractsADDITIONAL SPECIMENS OF SUDAMERICID (GONDWANATHERIA) MAMMALS FROM THE EARLY PALEOCENE OF ARGENTINAPALAEONTOLOGY, Issue 5 2008YAMILA GUROVICH Abstract:, The extinct, Cretaceous,Paleogene Gondwanatherians have previously been considered to be early xenarthrans, multituberculates and more recently Mammalia incertae sedis. However, the phylogenetic relationships of Gondwanatheria have yet to be resolved. In this paper, additional dental specimens of the gondwanatherian Sudamerica ameghinoi from the Early Paleocene Salamanca Formation of Argentina are described. These specimens provide additional information on Gondwanatheria affinities, sudamericid morphology and help support earlier hypotheses on Sudamerica dental formula and tooth categories. Sudamericid dental functional morphology and body mass estimates, based on measurements of isolated teeth, are inferred. Dental morphology such as hypsodonty, enamel microstructure and crown features do support a robust clade for Sudamericidae. [source] The ancient inhabitants of Jebel Moya redux: measures of population affinity based on dental morphologyINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 2 2007J. D. Irish Abstract This paper reexamines some of the methods and craniometric findings in the classic volume The Ancient Inhabitants of Jebel Moya (Sudan) (1955) by Mukherjee, Rao & Trevor, in light of recent archaeological data and relative to a new dental morphological study. Archaeological evidence characterises these inhabitants as having been heavily influenced by outside sources; yet they managed to establish and maintain their own distinctive culture as seen in the site features and surviving artefact collections. The dental study, modelled after the original craniometric-based investigation and using the same or similar comparative samples, detected complementary indications of outside biological influence. In the study, up to 36 dental traits were recorded in a total of 19 African samples. The most influential traits in driving inter-sample variation were then identified, and phenetic affinities were calculated using the Mahalanobis D2 statistic for non-metric traits. If phenetic similarity provides an estimate of genetic relatedness, these affinities, like the original craniometric findings, suggest that the Jebel Moyans exhibited a mosaic of features that are reminiscent of, yet distinct from, both sub-Saharan and North African peoples. Together, these different lines of evidence correspond to portray the Jebel Moya populace as a uniform, although distinct, biocultural amalgam. Copyright © 2006 John Wiley & Sons, Ltd. [source] Inferring parrotfish (Teleostei: Scaridae) pharyngeal mill function from dental morphology, wear, and microstructureJOURNAL OF MORPHOLOGY, Issue 10 2006Andrew Carr Abstract Morphology, occlusal surface topography, macrowear, and microwear features of parrotfish pharyngeal teeth were investigated to relate microstructural characteristics to the function of the pharyngeal mill using scanning electron microscopy of whole and sectioned pharyngeal jaws and teeth. Pharyngeal tooth migration is anterior in the lower jaw (fifth ceratobranchial) and posterior in the upper jaw (paired third pharyngobranchials), making the interaction of occlusal surfaces and wear-generating forces complex. The extent of wear can be used to define three regions through which teeth migrate: a region containing newly erupted teeth showing little or no wear; a midregion in which the apical enameloid is swiftly worn; and a region containing teeth with only basal enameloid remaining, which shows low to moderate wear. The shape of the occlusal surface alters as the teeth progress along the pharyngeal jaw, generating conditions that appear suited to the reduction of coral particles. It is likely that the interaction between these particles and algal cells during the process of the rendering of the former is responsible for the rupture of the latter, with the consequent liberation of cell contents from which parrotfish obtain their nutrients. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Genetic integration of molar cusp size variation in baboonsAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Christina Koh Abstract Many studies of primate diversity and evolution rely on dental morphology for insight into diet, behavior, and phylogenetic relationships. Consequently, variation in molar cusp size has increasingly become a phenotype of interest. In 2007 we published a quantitative genetic analysis of mandibular molar cusp size variation in baboons. Those results provided more questions than answers, as the pattern of genetic integration did not fit predictions from odontogenesis. To follow up, we expanded our study to include data from the maxillary molar cusps. Here we report on these later analyses, as well as inter-arch comparisons with the mandibular data. We analyzed variation in two-dimensional maxillary molar cusp size using data collected from a captive pedigreed breeding colony of baboons, Papio hamadryas, housed at the Southwest National Primate Research Center. These analyses show that variation in maxillary molar cusp size is heritable and sexually dimorphic. We also estimated additive genetic correlations between cusps on the same crown, homologous cusps along the tooth row, and maxillary and mandibular cusps. The pattern for maxillary molars yields genetic correlations of one between the paracone,metacone and protocone,hypocone. Bivariate analyses of cuspal homologues on adjacent teeth yield correlations that are high or not significantly different from one. Between dental arcades, the nonoccluding cusps consistently yield high genetic correlations, especially the metaconid,paracone and metaconid,metacone. This pattern of genetic correlation does not immediately accord with the pattern of development and/or calcification, however these results do follow predictions that can be made from the evolutionary history of the tribosphenic molar. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source] Brief communication: Population variation in human maxillary premolar accessory ridges (MxPAR)AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Scott E. Burnett Abstract The purpose of this brief communication is to report the results of an analysis of maxillary premolar accessory ridges (MxPAR), a common but understudied accessory ridge that may occur both mesial and distal to the central ridge of the buccal cusp of upper premolars. We developed a new five-grade scoring plaque to better categorize MxPAR variation. Subsequently, we conducted a population analysis of MxPAR frequency in 749 dental casts of South African Indian, American Chinese, Alaskan Eskimo, Tohono O'odham (Papago), Akimel O'odham (Pima), Solomon Islander, South African Bantu, and both American and South African Whites. Northeast Asian and Asian-derived populations exhibited the highest MxPAR frequencies while Indo-European samples (South African Indians, American and South African Whites) exhibited relatively low frequencies. The Solomon Islanders and South African Bantu samples exhibited intermediate frequencies. Our analysis indicates that statistically significant differences in MxPAR frequency exist between major geographic populations. As a result, the MxPAR plaque has now been added to the Arizona State University Dental Anthropology System, an important contribution as maxillary premolar traits are underrepresented in analyses of dental morphology. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source] A new species of Pliopithecus Gervais, 1849 (Primates: Pliopithecidae) from the Middle Miocene (MN8) of Abocador de Can Mata (els Hostalets de Pierola, Catalonia, Spain)AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2010David M. Alba Abstract Pliopithecus (Pliopithecus) canmatensis sp. nov. is described from several Late Aragonian localities from Abocador de Can Mata (ACM) in els Hostalets de Pierola (Vallès-Penedès Basin, Catalonia, Spain), spanning from ,11.7 to 11.6 Ma (C5r.3r subchron), and being correlated to the MN8 (reference locality La Grive L3). The ACM remains display a pliopithecine dental morphology with well-developed pliopithecine triangles on M/2 and M/3. This, together with other occlusal details, negates an attribution to the subgenus Epipliopithecus. Although slightly smaller, the ACM remains are most similar in size to comparable elements of P. piveteaui and P. antiquus. Several occlusal details (such as the greater development of the buccal cingulid in lower molars) and dental proportions (M/3 much longer than M/2), however, indicate greater similarities with P. antiquus from Sansan and La Grive. The ACM remains, however, differ from P. antiquus in dental proportions as well as occlusal morphology of the lower molars (including the less peripheral position of the protoconid and more medial position of the hypoconulid, the more mesial position of the buccal cuspids as compared to the lingual ones, the narrower but distinct mesial fovea, the higher trigonid, and the more extensive buccal cingulid, among others). These differences justify a taxonomic distinction at the species level of the ACM pliopithecid remains with respect to P. antiquus. Previous pliopithecid findings from the Vallès-Penedès Basin, previously attributed to P. antiquus, are neither attributable to the latter species nor to the newly erected one. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source] New Phylogenetic Analysis of the Family Elephantidae Based on Cranial-Dental Morphology,THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 1 2010Nancy E. Todd Abstract In 1973, Vincent Maglio published a seminal monograph on the evolution of the Elephantidae, in which he revised and condensed the 100+ species named by Henry Fairfield Osborn in 1931. Michel Beden further revised the African Elephantidae in 1979, but little systematic work has been done on the family since this publication. With addition of new specimens and species and revisions of chronology, a new analysis of the phylogeny and systematics of this family is warranted. A new, descriptive character dataset was generated from studies of modern elephants for use with fossil species. Parallel evolution in cranial and dental characters in all three lineages of elephants creates homoplastic noise in cladistic analysis, but new inferences about evolutionary relationships are possible. In this analysis, early Loxodonta and early African Mammuthus are virtually indistinguishable in dental morphology. The Elephas lineage is not monophyletic, and results from this analysis suggest multiple migration events out of Africa into Eurasia, and possibly back into Africa. New insight into the origin of the three lineages is also proposed, with Stegotetrabelodon leading to the Mammuthus lineage, and Primelephas as the ancestor of Loxodonta and Elephas. These new results suggest a much more complex picture of elephantid origins, evolution, and paleogeography. Anat Rec, 2010. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||