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Title: Metric analysis of Homo first mandibular molars with special attention to Sima de los Huesos site (Atapuerca, Burgos)
Authors: Martín-Albaladejo, Marina
Martinón-Torres, María
Bermúdez de Castro, José María
Issue Date: 2014
Publisher: International Union for Prehistoric and Protohistoric Sciences (IUPPS)
Citation: XVII World UISPP Congress, 2014, p. 61
Abstract: The study of dental remains is a wealthy and stable source of information about phylogenetic relationships between extinct hominin species. Metric dental features are a reliable indicator of the underlying genotype of the individual/species under study. Since the last systematic metric analysis of the Atapuerca-Sima de los Huesos (SH) lower molars (Bermúdez de Castro and Nicolás, Am. J. Phys. Anthropol., 1995) the sample has substantially increased, so an updated assessment is necessary. Lower molars were the most abundant dental remains present in Sima de los Huesos, and first lower molars (M1) are the most stable teeth within the lower molar series. For this study we excluded M1 with a wear degree higher than 3 (Molnar, Am. J. Phys. Anthropol., 1971). Thus, the analysed sample results in 26 SH M1s, assigned to 19 individuals. SH was compared to a large sample of Contemporary Homo sapiens (N=253) held at the Anthropological Museum of the University of Coimbra (Portugal), Early Homo sapiens (N=7), Homo neanderthalensis (N=6), Homo heidelbergensis (N=2), Homo antecessor (N=2), Early Homo from Africa (N=3) and Early Homo from Asia (N=5) specimens. For each specimen we measured the total crown area and the absolute and relative area of each of the main cusps. The areas were measured with Ushikata X-PLAN360d planimeter over scaled high quality photographs of the teeth. Statistical comparison of the differences among groups, Principal Component Analysis and Linear Correlations between absolute and relative cusp areas were applied using PAST 2.17 and SPSS Statistics software. SH M1s are, in absolute terms, as small as contemporary Homo sapiens and they do not differ significantly from Early Homo sapiens. Furthermore, there are significant differences between the M1 cusp areas of Early Homo taxa in general and those of later Homo species. SH M1protoconid relative area is the largest of all the studied groups. In the Principal Component Analysis (PCA) for the cusps absolute areas we found an area exclusively occupied by contemporary Homo sapiens and SH populations, whereas Homo antecessor falls closer to earlier Homo taxa. In contrast, in the PCA for the cusp relative areas, 4 out of 6 Neanderthal specimens falls within SH variability. Contemporary Homo sapiens presents a wide range of variation that encloses both Neanderthal and SH distributions among other groups. From a metric aspect, M1s are notably stable, although it is possible to find some differences between the larger specimens of Early Homo and the smaller M1s in later Homo taxa groups. The highest relative area of the protoconid in SH concurs with the highest area of the homologous cusp in the upper molar series (Martinón- Torres et al., J. Anat., 2013). The reduction in the total crown and absolute cusps areas in both SH and contemporary Homo sapiens suggests a likely case of parallelism. Although in absolute terms neanderthal molars are larger than those of SH, regarding the relative cusp areas SH and Neanderthals are similar. An exploration of other dental classes would be necessary to investigate the processes behind the dental reduction in the genus Homo.
Description: Póster presentado en: XVII World UISPP Congress, 1-7 de septiembre 2014, Burgos
Type: Presentation
Appears in Collections:Congresos, encuentros científicos y estancias de investigación

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