Estudio del desgaste a nivel microcópico de los dientes anteriores de los homínidos del yacimiento pleistocénico de sima de los huesos (sierra de atapuerca, Burgos)

Identificador:  TDX:392

Handle: https://hdl.handle.net/20.500.11797/TDX392

Autores:  Lozano Ruiz, Marina

Resumen:
EN INGLÉS TESIS MARINA LOZANO RUIZ<br/><br/>'Study of microscopic dental wear of human anterior teeth of the Sima de los Huesos Middle Pleistocene site (Sierra de Atapuerca, Burgos).'<br/><br/>Dentition is, together with hands, one of parts of human body in direct contact with exterior items. Hands and teeth used simultaneously allow us make a great amount of tasks for processing and modifying many materials. <br/> The different ancient Homo species have used their teeth for processing food previous to their ingestion. The front part of dental arcade is very versatile since not only it can be used for preparing foodstuff, but also for processing vegetable fibers and materials of animal origin like sinews and furs.<br/> The activities that imply anterior teeth contact with different materials can produce signals and marks on dental surfaces. These alterations will get more or less marked according to the intensity of these activities. This fact has not slipped by for many researchers that they have examined, macro and microscopically, the features of wear present in dental enamel. Nowadays, we have a well-established typology of microwear features that allow us identify formation processes. <br/> In Sima de los Huesos (SH) site (Sierra de Atapuerca, Burgos), human remains belonging to twenty-eight individuals have been found. We consider the SH hominin sample as representative of Homo heidelbergensis species dated in 400.000 years BP. The current dental sample includes a total of 479 teeth, 163 of they are incisors and canines. We document the presence of many obliquely oriented cultural striations on buccal surface of anterior teeth. This type of scratching was the result of use of anterior dentition as a third hand. SH individuals perform the 'stuff and cut' technique. <br/> In this work we have confirmed this aetiology, and we have determined that the entire SH sample have this kind of dental wear. Moreover, we can find other dental wear features as enamel chipping on buccal and oclusal surfaces, vestibule-lingual striations and enamel polishing on oclusal surface. All of these features indicate us that SH hominin perform extramasticatory activities with anterior teeth. Presence of these features in all hominin group of SH may suggest that this behaviour was common for both sexes and age groups. <br/> Data obtained from SH dental sample has been compared with data of two modern hunter-gatherer populations: Eskimos and Australian Aborigine. We can found the same dental wear features in these three populations. However, some kinds of wear features like cultural striations and vestibule-lingual striations are underrepresented in modern groups. This fact lead us to establish that modern hunters-gatherers carry out similar activities that fossil group, but with a lesser intensity and temporal frequency. <br/> Results of this study indicate that SH hominids employed their anterior teeth as tools. The extramasticatory activities are related with processing of vegetable fibers and animal sinews that are passed through anterior teeth repeatedly, and then fibers were cut with a lithic tool. The cultural striations would be produced when cutting the materials clasped between the teeth.<br/> We can conclude that analysis of wear features on SH anterior teeth suggest that these hominins employed their teeth for tasks related with processing of environment resources for purposes beyond survival. The presence of a similar proportion of dental wear in all SH sample suggests a systematic behaviour which extended throughout life.