Tooth Morphology Research Papers - Academia.edu (original) (raw)

Fourier analyses allow extracting parameters from the outline of tooth crowns, which can be used in multivariate analyses. However, the great complexity of some dental shapes forces to check for the intrinsic error produced in this... more

The view that Aurignacian technologies and their associated symbolic manifestations represent the archaeologicalproxy for the spread of Anatomically Modern Humans into Europe, is supported by few diagnostic human remains, including those... more

The view that Aurignacian technologies and their associated symbolic manifestations represent the archaeologicalproxy for the spread of Anatomically Modern Humans into Europe, is supported by few diagnostic human remains, including those from the Aurignacian site of Les Rois in south-western France. Here we reassess the taxonomic attribution of the human remains, their cultural affiliation, and provide five new radiocarbon dates for the site. Patterns of tooth growth along with the morphological and morphometric analysis of the human remains indicate that a juvenile mandible showing cutmarks presents some Neandertal features, whereas another mandible is attributed to Anatomically Modern Humans. Reappraisal of the archaeological sequence demonstrates that human remains derive from two layers dated to 28-30 kyr BP attributed to the Aurignacian, the only cultural tradition detected at the site. Three possible explanations may account for this unexpected evidence. The first one is that ...

The phylogenetic position of many fossil platyrrhines with respect to extant ones is not yet clear. Two main hypotheses have been proposed: the layered or successive radiations hypothesis suggests that Patagonian fossils are Middle... more

The phylogenetic position of many fossil platyrrhines with respect to extant ones is not yet clear. Two main hypotheses have been proposed: the layered or successive radiations hypothesis suggests that Patagonian fossils are Middle Miocene stem platyrrhines lacking modern descendants, whereas the long lineage hypothesis argues for an evolutionary continuity of all fossil platyrrhines with the extant ones. Our geometric morphometric analysis of a 15 landmark-based configuration of platyrrhines' first and second lower molars suggest that morphological stasis may explain the reduced molar shape variation observed. Platyrrhine lower molar shape might be a primitive retention of the ancestral state affected by strong ecological constraints throughout the radiation of the main platyrrhine families. The Patagonian fossil specimens showed two distinct morphological patterns of lower molars, Callicebus—like and Saguinus—like, which might be the precursors of the extant forms, whereas the Middle Miocene specimens, though showing morphological resemblances with the Patagonian fossils, also displayed new, derived molar patterns, Alouatta—like and Pitheciinae—like, thereby suggesting that despite the overall morphological stasis of molars, phenotypic diversification of molar shape was already settled during the Middle Miocene.

Abstract The non-metric characteristics like the tooth shape, number of cusps and other structural features contribute for the forensic and anthropological investigations and in establishing the population inter-relationships. The... more

Abstract The non-metric characteristics like the tooth shape, number of cusps and other structural features contribute for the forensic and anthropological investigations and in establishing the population inter-relationships. The mandibular 2nd premolar and the maxillary 2nd molars often show variations in their occlusal morphology. The Hardy-Weinberg equilibrium is applied in a novel way to determine the cusp phenotype in these two teeth in a representative sample from Gujarati population. The dental stone models of 295 students of dental college in the age range of 19–23 years were used for this study. The two-cusped second premolar was present in around 60% the subjects on both the right and left side. There is no significant difference in the distribution of the number of cusps in both the right and left second premolars between male and female subjects. There was a significant difference in the distribution of the number of cusps in left second molar between male and female (χ2 = 4.073, df = 2, p

The ontogenetic trajectory of a marginal jawbone of Lophosteus superbus (Late Silurian, 422 Million years old), the phylogenetically most basal stem osteichthyan, visualized by synchrotron microtomography, reveals a developmental... more

The ontogenetic trajectory of a marginal jawbone of Lophosteus superbus (Late Silurian, 422 Million years old), the phylogenetically most basal stem osteichthyan, visualized by synchrotron microtomography, reveals a developmental relationship between teeth and dermal odontodes that is not evident from the adult morphology. The earliest odontodes are two longitudinal founder ridges formed at the ossification center. Subsequent odontodes that are added lingually to the ridges turn into conical teeth and undergo cyclic replacement, while those added labially achieve a stellate appearance. Stellate odontodes deposited directly on the bony plate are aligned with the alternate files of teeth, whereas new tooth positions are inserted into the files of sequential addition when a gap appears. Successive teeth and overgrowing odontodes show hybrid morphologies around the oral-dermal boundary, suggesting signal cross-communication. We propose that teeth and dermal odontodes are modifications o...

Romero A, Galbany J & Pérez-Pérez A (2016) Ecología dental en primates y homininos fósiles. In: Homenaje al Dr. José Gibert Clols. Una vida dedicada a la ciencia y al conocimiento de los primeros europeos (Coordinador: Ribot Trafí F).... more

Romero A, Galbany J & Pérez-Pérez A (2016) Ecología dental en primates y homininos fósiles. In: Homenaje al Dr. José Gibert Clols. Una vida dedicada a la ciencia y al conocimiento de los primeros europeos (Coordinador: Ribot Trafí F). Granada: Publicaciones Diputación de Granada. Pp. 163-175. ABSTRACT: La ecología dental es un enfoque clave para explicar cómo el diente responde al medioambiente en aspectos relacionados con la morfología y procesos de desgaste en la reconstrucción de las estrategias alimentarias en primates no-humanos y homininos fósiles desde una perspectiva evolutiva. Estudios morfométricos comparativos muestran como los dientes son estructuras óptimas para la masticación. Sin embargo, la forma y tamaño entre especies dependen en gran medida de limitaciones en el desarrollo, filogenia y ecología. En particular, la topografía oclusal varía en relación a la ecología alimentaria entre primates y refleja su adaptación para el procesamiento mecánico durante la alimentación. Dado que la funcionalidad óptima del diente puede variar con el desgaste, la interacción entre factores ecológicos y la pérdida de esmalte en primates no-humanos para inferir la dieta de especies extintas no se encuentra bien establecida. En este trabajo abordamos los problemas actuales en el estudio del desgaste dental a escala macro y microscópica relativos a las propiedades mecánicas de los alimentos y factores ecológicos. Nuestros estudios in vivo con primates cercopitécidos y poblaciones de cazadores-recolectores plantean nuevas preguntas y temas de discusión acerca de las propiedades físicas de los alimentos en el contexto del estudio sobre el desgaste dental. Palabras clave: Desgaste; diente; ecología alimentaria; primates.

Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are prone to facilitate ecological separation which might lead to an adaptive radiation. Examples of such radiations can be found in the... more

Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are prone to facilitate ecological separation which might lead to an adaptive radiation. Examples of such radiations can be found in the Mediterranean for the genera Candiacervus (Crete), Nesogoral (Sardinia) and Hoplitomeryx (Gargano). A different strategy to cope with limited resources on islands is generalism. We test whether populations of the endemic bovid Myotragus balearicus from two sites and Pleistocene as well as Holocene levels on Mallorca island displays ecological separation indicated by diet, or whether the species shifted its dietary trait towards generalism. We expect to find either: (1) dietary divergence in space and time (between sites and stratigraphic levels), which would indicate niche partitioning and/or a shift in dietary traits due to environmental influences; or (2) dietary congruence in a less specialised, generalistic dietary strategy in space and time which would indicate a flexible trait to cope with instable resource availability. We compare individuals from a fossil assemblage at a northern site and one assemblage from the eastern coast in terms of their dietary traits. Traits are reconstructed using dental dietary proxies, complementary in time scale and resolution. (1) 3D-dental topometry and (2) enamel surface texture analysis. Data suggest that individuals from both assemblages of M. balearicus behaved as variable browse dominated intermediate feeders. We thus conclude that the observed variability relates to a shift towards generalism as a subsistence strategy. We consider hypsodonty the pre-adaptation for this life style that enabled M. balearicus to exploit almost any food source in its energetically restricted island habitat.

Fourier Los análisis de Fourier permiten caracterizar el contorno del diente y obtener una serie de paráme-tros para un posterior análisis multivariante. Sin embargo, la gran complejidad que presentan algu-nas formas obliga a determinar... more

Fourier Los análisis de Fourier permiten caracterizar el contorno del diente y obtener una serie de paráme-tros para un posterior análisis multivariante. Sin embargo, la gran complejidad que presentan algu-nas formas obliga a determinar el error de medición intrínseco que se produce. El objetivo de este trabajo es aplicar y validar los análisis de Fourier en el estudio de la forma dental del segundo mo-lar inferior (M2) de cuatro especies de primates Hominoidea para explorar la variabilidad morfo-métrica interespecífica, así como determinar el error de medición a un nivel intra e interobserva-dor. El contorno de la superficie oclusal del diente fue definido digitalmente y con las funciones derivadas del análisis de Fourier se realizaron Análisis Discriminantes y Test de Mantel (correla-ciones de Pearson) para determinar las diferencias de forma a partir de las mediciones tomadas. Los resultados indican que el análisis de Fourier muestra la variabilidad de forma en dientes mola-res e...

The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the oldest Australopithecus afarensis collections as well as other well preserved non-hominin primate remains, including primate cercopithecids.... more

The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the oldest Australopithecus afarensis collections as well as other well preserved non-hominin primate remains, including primate cercopithecids. The Laetoli primates are highly diversified, including fossil galagines, parapithecids and paracolobines. These primate species are indicative of highly variable depositional environments at Laetoli that would have been more wooded or forested with patches of bushes, thorn scrubs and open habitats. This research presents qualitative descriptions and a comparative computational statistical analysis (PCA and DFA) of odontometrics for the posterior teeth of fossil and extant primates as a way to securely classify recently recovered Laetoli fossil primate remains by the University of Colorado Denver Tanzania field school in paleoanthropology. The statistical analyses show that the posterior teeth can be used to distinguish speciation since tooth size can be indicative of dietary adaptations and habitat preferences. For instance, the PCA yields information on general groupings based on habitat preferences, whereas the DFA shows that the buccal teeth have a higher discriminatory power than the premolars; however M3 has the highest discriminatory ability in deciphering primate species and exhibits the lowest misclassification percentage (15.88%) for all tooth types although it is known that it possess the highest variability in tooth size and shape. The results of this analysis and classification of unknown primate species provides a better understanding of the ecological diversity exploited at Laetoli during the Pliocene and contributes to our understanding of primate diversity and dietary behaviors at Laetoli.