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Dental Characters (dental + character)
Selected AbstractsNew visions of dental tissue research: Tooth development, chemistry, and structureEVOLUTIONARY ANTHROPOLOGY, Issue 5 2008Tanya M. Smith Abstract Teeth are one of the best preserved and most commonly recovered elements in primate fossil assemblages. Taxonomic, functional, and phylogenetic hypotheses often rely on dental characters, despite considerable evidence of homoplasy in tooth form and large variation in tooth size within and among primates.1,2 Recent studies have led to new areas of research centered on incremental tooth development, chemical composition, and internal structure. Due to rapid technological developments in imaging and elemental sampling, these new approaches have the potential to increase our understanding of developmental biology, including not only changes in the pace of growth and reproduction, but also our assessments of diets, migration patterns, environments, and taxonomy. The integration of these temporal, chemical, and structural approaches heralds a bright future for the role of dental tissue research in evolutionary anthropology. © 2008 Wiley-Liss, Inc. [source] Form and function of the selenodont molar in southern African ruminants in relation to their feeding habitsJOURNAL OF ZOOLOGY, Issue 1 2002Debbie Archer Abstract The general aim of the present study was to test whether there are differences in the occlusal design of the ruminant selenodont molar, and by examining correlations between tooth form and diet, improve our understanding of the function of the selenodont molar within the Bovidae. Twenty-six species of bovid ruminants were grouped into the three feeding types established by Hofmann (1968) , i.e. browsers, grazers and intermediate feeders. The characteristics of the shape, number, width and length of the enamel ridges were found to correlate with the hypothesized function of the molar occlusal surface. These follow the principles applied to non-bovid species where adaptation of the occlusal surface has been investigated in some detail. Thirteen characteristics of the occlusal surface were scored. ANOSIM results reject the null hypothesis that there are no differences in the selenodont molar occlusal surface. SIMPER results showed that all the characteristics scored contributed to the differences between groups, and crown height was not explaining the major dissimilarity between feeding groups. Differences in enamel ridge characteristics between feeding types suggest that food is being processed in essentially different ways by the browsers and grazers. Intermediate feeding species cluster within the other feeding types, depending on what the major component of the diet is. The grouping produced by the MDS, based on dental characters, closely agrees with Hofmann's classification based on gut structure. [source] Talar morphology, phylogenetic affinities, and locomotor adaptation of a large-bodied amphipithecid primate from the late middle eocene of MyanmarAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Laurent Marivaux Abstract A well-preserved fossil talus [National Museum of Myanmar Primates (NMMP) 82] of a large-bodied primate is described from the late middle Eocene Pondaung Formation of central Myanmar. The specimen was collected at Thandaung Kyitchaung, a well-known amphipithecid primate,bearing locality near the village of Mogaung. NMMP 82 adds to a meager but growing sample of postcranial remains documenting the large-bodied primates of the Pondaung Formation. This new talus exhibits a suite of features that resemble conditions found in living and fossil haplorhine primates, notably anthropoids. As such, the phylogenetic signal deriving from the morphology of NMMP 82 conflicts with that provided by NMMP 20, a partial skeleton (including a fragmentary calcaneus) of a second large-bodied Pondaung primate showing undoubted adapiform affinities. Analysis subtalar joint compatibility in a hypothetical NMMP 82/NMMP 20 combination (talus/calcaneus) reveals a substantial degree of functional mismatch between these two tarsal bones. The functional incongruence in subtalar joint morphology between NMMP 20 and NMMP 82 is consistent with the seemingly divergent phylogenetic affinities of these specimens, indicating that two higher level taxa of relatively large-bodied primates are documented in the Pondaung Formation. On the basis of its size and morphology, we refer the NMMP 82 talus to the large-bodied amphipithecid Pondaungia. The occurrence of anthropoid-like tali in the Pondaung Formation obviates the need to invoke homoplasy to explain the shared, derived dental characters that are common to amphipithecids and undoubted anthropoids. Functionally, the NMMP 82 talus appears to have pertained to a primate that is engaged in active quadrupedalism in an arboreal environment along broad and subhorizontal branches. The primate taxon represented by NMMP 82 was capable of climbing and leaping, although it was not particularly specialized for either of these activities. Am J Phys Anthropol 143:208,222, 2010. © 2010 Wiley-Liss, Inc. [source] Khoratpithecus piriyai, a Late Miocene hominoid of ThailandAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2006Yaowalak Chaimanee Abstract A Khoratpithecus piriyai lower jaw corresponds to a well-preserved Late Miocene hominoid fossil from northeastern Thailand. Its morphology and internal structure, using a microcomputed tomography scan, are described and compared to those of other known Miocene hominoids. It originated from fluviatile sand and gravel deposits of a large river, and was associated with many fossil tree trunks, wood fragments, and large vertebrate remains. A biochronological analysis by using associated mammal fauna gives an estimated geological age between 9,6 Ma. The flora indicates the occurrence of a riverine tropical forest and wide areas of grassland. K. piriyai displays many original characters, such as the great breadth of its anterior dentition, suggesting large incisors, large lower M3, a canine with a flat lingual wall, and symphysis structure. Several of its morphological derived characters are shared with the orangutan, indicating sister-group relationship with that extant ape. This relationship is additionally strongly supported by the absence of anterior digastric muscle scars. These shared derived characters are not present in Sivapithecus, Ankarapithecus, and Lufengpithecus, which are therefore considered more distant relatives to the orangutan than Khoratpithecus. The Middle Miocene K. chiangmuanensis is older, displays more primitive dental characters, and shares several dental characters with the Late Miocene form. It is therefore interpreted as its probable ancestor. But its less enlarged M3 and more wrinkled enamel may suggest an even closer phylogenetic position to orangutan ancestors, which cannot yet be supported because of the incomplete fossil record. Thus Khoratpithecus represents a new lineage of Southeast Asian hominoids, closely related to extant great ape ancestors. Am J Phys Anthropol 2006. © 2006 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] | ||||||||||