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[Abstract] The techniques of agriculture and animal husbandry at Tell Humeida, a Middle Uruk Period (Late Chalcolithic) site on the middle Syrian Euphrates, were studied using stable isotopes of bone collagen of domestic and wild mammals and from cereal and ruderal plant seeds. Two archaeological campaigns in 2009 and 2011 yielded a small collection of bones, most of which were taxonomically indeterminable. The work had to be interrupted due to the political conflict. The faunal study comprised collagen peptide fingerprinting for taxonomic identification, followed by isotopic analysis. Multiple 14C dating were performed to date the infill to around 3600 cal BC. An isotopic analysis of the sparse plant remains suggested that irrigation and manuring were common practices. Sheep and equids predominated in the faunal assemblage. Sheep grazed on manured soils, and their diet could include millet or another C4 plant, of which, however, no carpological remains were found. The diet of equids differed from that of sheep but also that of other wild ungulates (cervids/gazelles). Their isotopic signatures indicated that they grazed in humid areas, near the watercourse. These finds indicated a settlement that was closely linked to the availability of water, which made it possible to grow crops in an almost desert-like area, and the rearing of sheep.

[Abstract] In the last decade, the identification of bone fragments by peptide mass fingerprinting or zooarchaeology by mass spectrometry is developing as a powerful tool in Quaternary palaeontology. The sequence of amino acids that make up the bone collagen molecule shows slight variations between taxa, which can be studied by mass spectrometry for taxonomic purposes. This requires reference databases that allow peptide identification. Although the cave bear (Ursus spelaeus Rosenmüller, 1794) is a common component in many European Pleistocene cave sites, no peptide fingerprint taxonomic study has paid special attention to this species up to now. For peptide markers in Ursidae, the most recent proposal is based on collagen obtained from a modern brown bear sample. In this work we attempt to cover this gap by studying bone collagen of cave and brown bear samples from different origins and different chronology, applying matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI TOF). We also performed an in-silico study of ursid bone collagen sequences published in databases. In our results we detected some discrepancies between the peptides obtained from both in silico and MALDI TOF analysis of fossil collagen and those published in the literature, in which we conclude that there are some misidentified peptides. The identification of skeletal remains by means of their peptide fingerprint is proving to be a powerful tool in palaeontology, which will bear greater fruit once the limitations of a technique that is in its initial stages have been overcome.

[Abstract] Stable isotope analysis of animal tissue samples is increasingly used to study the trophic ecology of target species. The isotopic signatures respond to the type of diet, but also to the environmental conditions of their habitat. In the case of omnivorous, seasonal or opportunistic feeding species, the interpretation of isotopic values is more complex, as it is largely determined by food selection, either due to individual choice or because of availability. We analysed C and N isotopes in brown bear (Ursus arctos) hair from four isolated populations of south-western Europe (Cantabrian, Pyrenees, Central Apennines and Alpine) accounting for the geographical and climatic differences among the four areas. We found inter-population differences in isotopic signatures that cannot be attributed to climatic differences alone, indicating that at least some bears from relatively higher altitude populations experiencing higher precipitation (Pyrenees) show a greater consumption of animal foods than those from lower altitudes (Cantabrian and Apennines). The quantification of isotopic niche space using Layman’s metrics identified significant similarities between the Cantabrian and Central Apennine samples that markedly differ from the Pyrenean and Alpine. Our study provides a baseline to allow further comparisons in isotopic niche spaces in a broad ranged omnivorous mammal, whose European distribution requires further conservation attention especially for southern isolated populations.

OBJETIVO: Analizar a lo largo de esta revisión sistemática la eficacia y predictibilidad de los movimientos dentales en la expansión transversal de la arcada, beneficios de los alineadores como terapia ortodóncica y la disponibilidad o ausencia de evidencia sobre la estabilidad de la arcada una vez finalizado el tratamiento. MATERIAL Y MÉTODO: Se realiza una búsqueda electrónica en las bases de datos PubMed, Cochrane, Medline, Web of Sciencey Scopus. La evaluación de la calidad de los estudios observacionales se realizó utilizando la herramienta ROBINS-I. La clasificación OCEM se utilizó para evaluar el nivel de evidencia de cada resultado identificado. RESULTADOS: Diez artículos (dos ensayos clínicos prospectivos y ocho retrospectivos) fueron incluidos en nuestra revisión sistemática. Nuestros estudios tuvieron un riesgo de sesgo moderado. CONCLUSIONES: Los alineadores demostraron ser una alternativa positiva para el movimiento de expansión, que ofrece un alto grado de predictibilidad y que favorece a la higiene oral del paciente. Es fundamental realizar pruebas CBCT y se hace evidente la necesidad de realizar un protocolo consensuado sobre las referencias anatómicas para que las mediciones sean objetivas y homogéneas en los futuros estudios. Se necesitan estudios a largo plazo sobre la expansión transversal con alineadores para valorar el éxito y la estabilidad de este tipo de tratamiento., OBJETIVE: To analyze throughout this systematic review the efficacy and predictability of dental movements in the transverse expansion of the arch, the aligners’ benefitsas orthodontic therapyand the availability or absence of evidence on the stability of the arch after treatment. MATERIAL AND METHODS: An electronic researchwas made using PubMed, Cochrane, Medline, Web of Scienceand Scopus databases. Quality assessment of observational studies was done by using the ROBINS-Itool and. The OCEM classification was used to assessevidence level for each identified outcome. RESULTS: Ten articles (two prospective and eight retrospective clinical trials) were included in our systematic review. Ourstudies had a moderate risk of bias.CONCLUSIONS: The aligners proved to be a positive alternative to the expansion movement, offering a high degree of predictability and enhancing the oral hygiene of the patient. It is essential to carry out CBCT tests and it is evident the need to developan agreed protocol on anatomical references so that the measurements would beobjective and homogeneous in future studies.Long-term studies about transverse expansion with aligners are needed to assess the success andstability of this type of treatment.

[Abstract] Cova dos Santos is a karstic cavity in Abadín (Lugo), in a hitherto unexplored area that may have been the natural route between the well-known Quaternary faunas of the Cantabrian Mountain Range and those located further south in Galicia, such as in the Serra do Courel. The surface surveys carried out during the topographic layout revealed the presence of deposits of bone remains, usually extremely fragmented, of medium and large vertebrates. Due to the nature of these remains, different molecular techniques (ZooMS, stable isotopes), radiocarbon dating, and morphological and metric analysis were used to characterise the remains present at the site. Combining these methods, it has been possible to identify different taxa such as Ursus speleaeus, Ursus arctos, Panthera pardus, Cervus elaphus, Rhinocerotidae, and to confirm the occupation of this cave since at least 43000 years ago calBP. The presence of domestic species, such as Ovis aries, Equus sp. and Gallus gallus, also shows the use of this cave in more recent times., [Resumen] Cova dos Santos es una cavidad kárstica en Abadín (Lugo), en una zona hasta ahora inexplorada que podría haber sido la ruta natural entre las conocidas faunas cuaternarias de la cordillera Cantábrica y las situadas más al sur de Galicia, como en la Serra do Courel. La prospección de superficie realizada durante los trabajos de trazado topográfico reveló la presencia de depósitos de restos óseos, generalmente muy fragmentados, pertenecientes a vertebrados de mediano y gran tamaño. Debido al carácter de estos restos, se emplearon distintas técnicas moleculares (ZooMS, isótopos estables), dataciones por radiocarbono, y análisis morfológico y métrico para poder caracterizar los restos presentes en el yacimiento. Combinando estos métodos, se han podido identificar distintos taxones como Ursus speleaeus, Ursus arctos, Panthera pardus, Cervus elaphus, Rhinocerotidae, y constatar la ocupación de esta cueva desde hace al menos 43.000 años calBP. La presencia de especies domésticas, como Ovis aries, Equus sp. o Gallus gallus, también pone de manifiesto el uso de esta cavidad en épocas más recientes.

OBJETIVO: Analizar a lo largo de esta revisión sistemática los efectos esqueléticos, dentoalveolares y en los tejidos blandos de la protracción maxilar con miniplacas en comparación con el tratamiento convencional y definir la edad óptima para ambos tratamientos. MATERIAL Y MÉTODO: Se realiza una búsqueda electrónica en las bases de datos PubMed, Cochrane, Medline y Scopus. La evaluación de la calidad de los estudios observacionales y el ensayo clínico aleatorizado se realizó utilizando las herramientas ROBINS y Cochrane de riesgo de sesgo, respectivamente. La clasificación OCEM se utilizó para evaluar el nivel de evidencia de cada resultado identificado. RESULTADOS: Once artículos (un ensayo clínico aleatorizado, dos estudios prospectivos y ocho retrospectivos) fueron incluidos en nuestra revisión sistemática. Nuestros estudios tuvieron un riesgo de sesgo moderado. CONCLUSIONES: Para obtener buenos resultados esqueléticos, la terapia clásica con máscara facial debe utilizarse lo antes posible durante el recambio dentario, mientras que el tratamiento con miniplacas puede hacerse durante la dentición permanente joven. Se observan mejores resultados dentoesqueléticos utilizando máscara facial con miniplacas. Se consigue estabilidad a largo plazo realizando un tratamiento temprano con máscara facial convencional. Sin embargo, se necesitan estudios a largo plazo sobre miniplacas., OBJETIVE: To analyze through this systematic review skeletal, dentoalveolar, and soft-tissue effects of maxillary protraction with miniplates compared with conventional facemask and define the optimal age to carry out both treatments. MATERIAL AND METHODS: An electronic serach was made using PubMd, Cochrane, Medline and Scopus databases. Quality assessment of observational studies and randomized control trial was done by using the ROBINS tool and Cochrane risk of bias tool, respectively. The OCEM classification was used to asses evidence level for each identified outcome. RESULTS: Eleven articles (one randomized controlled trial, two prospective studies and eight retrospective studies) were included in our systematic review. Our studies had a moderate risk of bias. CONCLUSIONS: To achieve favorable skeletal outcomes, the classic therapy with facemask should be used along dental replacement as soon as possible, whereas miniplates treatment could be used during young permanent dentition. Enhanced dento-skeletal outcomes have been observed using facemask with miniplates. A long-term stability has been achieved with an early treatment with conventional facemask. However, long-term studies about miniplates are needed.

Philosophy provides us with an innovative —as well as ancient— proposal to develop the capacity to think, build knowledge and generate collective stories through several approaches based on philosophical dialogues in communities of inquiry. These communities improve their thinking, social and communication skills, their philosophical attitudes, and they also become aware of their own thought processes. The common objective is to improve how we think. This work’s contributions can be summed up as: 1) An interdisciplinary theoretical framework for thought building, unifying two approaches: philosophical and psychological; 2) A description of the main current international programs related to philosophy for/with children; 3) A critical analysis and guidance on how to apply it in schools., La Filosofía retorna a nuestros días con una innovadora y a su vez antigua propuesta con la que desarrollar la capacidad de pensar, de construir conocimiento y de generar narraciones colectivas a través de diversas propuestas centradas en los diálogos filosóficos en comunidades de investigación. Dentro de estas comunidades se desarrollan habilidades de pensamiento, habilidades sociales y comunicativas, actitudes filosóficas a la vez que se toma conciencia de los propios procesos de pensamiento. Todo con un común objetivo: pensar mejor. Las aportaciones de este trabajo se resumen en: (1) un marco teórico interdisciplinar sobre la construcción de pensamiento que unifica dos enfoques (el filosófico y el psicológico), (2) una descripción de los principales programas internacionales existentes sobre Filosofía para/con niños y niñas y (3) un análisis crítico y orientaciones sobre su aplicación en la práctica escolar.

In this paper we performed stable isotope analysis on bone collagen of 81 samples from at least 39 brown bears (Ursus arctos) dating from Late Pleistocene to nowadays, that lived in the western of the Cantabrian Mountains. To interpret the data obtained we compared brown bear stable isotope signatures with those of cave bears (Ursus spelaeus), red deer (Cervus elaphus), and humans (Homo sapiens) from the same area. We observed that the diet of cave bears and brown bears in the Cantabrian Mountains was based on vegetable matter, although their different isotopic signatures suggest different ecological niches: wooded lowlands for the cave bear and steep highlands with scarce tree cover for the brown bear. In the Holocene brown bear maintains isotopic signatures similar to the Pleistocene ones in spite of the climatic tempering, which seems to be related to an even greater displacement toward the uplands due to a greater anthropic pressure in the ecosystem.

[Abstract] The European brown bear (Ursus arctos) shows a particular phylogeography that has been used to illustrate the model for contraction-expansion dynamics related to glacial refugia in Southern European peninsulas. Recent studies, however, have nuanced the once generally accepted paradigm, indicating the existence of cryptic refugia for some species further north. In this paper we collected available data on chronology and mitochondrial haplotypes from Western European brown bears, adding new sequences from present day individuals from the Cantabrian (North Iberia) area, in order to reconstruct the dynamics of the species in the region. Both genetics and chronology show that the Iberian Pleistocene lineages were not the direct ancestors of the Holocene ones, the latter entering the Peninsula belatedly (around 10,000 years BP) with respect to other areas such as the British Isles. We therefore propose the existence of a cryptic refugium in continental Atlantic Europe, from where the bears would expand as the ice receded. The delay in the recolonization of the Iberian Peninsula could be due to the orographic characteristics of the Pyrenean-Cantabrian region and to the abundant presence of humans in the natural entrance to the Peninsula.

[Resumen] El análisis de isótopos estables mediante espectrometría de masas para relaciones isotópicas (E.M.R.I.) es una herramienta clave en la trazabilidad alimentaria por su potencial para reconstruir la dieta de los animales a partir de los valores isotópicos en los productos cárnicos derivados de ellos. Se tomaron 13 muestras de productos cárnicos de pollo, vacuno y cerdo, algunos de marcas conocidas, otros de marca blanca y otros procedentes de cría particular, con distintos grados de conocimiento sobre los regímenes de alimentación de los animales de los cuales procedían. Se tomaron también muestras de posibles alimentos de interés: bellota, castaña, maíz, pienso y hierba. Todas las muestras (las de carne desengrasadas previamente) fueron cuidadosamente homogeneizadas y enviadas a los Servicios de Apoyo a la Investigación (SAI) de la Universidade da Coruña para el análisis de los isótopos estables de carbono y nitrógeno. Los datos así obtenidos de las muestras de carne y alimentos fueron comparados entre sí y con respecto a datos procedentes de la literatura preexistente. La señal isotópica de 13C resultó útil para comprobar la alimentación a base de maíz en pollos y a base de pasto en vacuno. La señal isotópica de 15N permitió detectar la leche materna en la dieta de terneras y la adición de proteína animal a los piensos en añojo y vacuno. Los análisis no sirvieron para diferenciar de forma fiable a los pollos camperos de los pollos criados en cautividad, ni para identificar de forma concluyente alimentación con bellotas o castañas en cerdos., [Resumo] A análise dos isótopos estables con espectrometría de masas para relacións isotópicas (E.M.R.I.) é unha ferramenta clave na trazabilidade alimentaria polo seu potencial para reconstruír a dieta dos animais a partir dos valores isotópicos dos produtos cárnicos derivados deles. Tomáronse 13 mostras de produtos cárnicos de polo, vacún e porco, algúns de marcas coñecidas, outros de marca branca e outros procedentes de cría particular, con distintos graos de coñecemento sobre os réximes de alimentación dos animais dos cales procedían. Tomáronse tamén mostras de posibles alimentos de interese: landra, castaña, millo, penso e herba. Todas as mostras (as de carne previamente desengraxadas) foron coidadosamente homoxeneizadas e mandadas aos Servizos de Apoio a Investigación (SAI) da Universidade da Coruña para a análise dos isótopos estables de carbono e nitróxeno. Os datos así obtidos das mostras de carne e alimentos foron comparados entre si e con datos procedentes da literatura preexistente. O sinal isotópico de 13C resultou útil para comprobar a alimentación a base de millo en polos e a base de pasto en vacún. As análises non serviron para diferenciar de maneira fiable aos polos campeiros dos polos criados en cativerio, nin para identificar de forma concluinte alimentación a base de landras ou castañas en porcos., [Abstract] Stable isotope analysis (S.I.A.) by isotope ratio mass spectrometry (I.R.M.S.) is a key tool for alimentary traceability thanks to its potential for the reconstruction of animal diets using the isotopic values of meat products. 13 samples of poultry, beef and pork meat products were collected, some from well-known brands, some from white-label brands and some from private breeding, with various degrees of knowledge about the feeding regime of the animals from which the products were originated. Samples of useful feeds: acorn, chestnut, corn, grass and commercial feed, were also taken. Every sample (the meat ones being previously degreased) was carefully homogenized and sent to the research support service of Universidade da Coruña for the analysis of stable isotopes of carbon and nitrogen. The obtained data from the meat and feed samples were contrasted with each other and with data from preexisting literature. The isotopic signature of 13C was useful to check the authenticity of corn-fed chicken and grass-fed beef. The isotopic signature of 15N allowed detection of breastfeeding in the diet of cattle and animal protein feeding in older beef animals. In contrast, this method didn’t allow an effective discrimination between free-range and barn chickens, nor a certain identification of acorn or chestnut feeding in pigs.

Ancient DNA studies have revolutionized the study of extinct species and populations, providing insights on phylogeny, phylogeography, admixture and demographic history. However, inferences on behaviour and sociality have been far less frequent. Here, we investigate the complete mitochondrial genomes of extinct Late Pleistocene cave bears and middle Holocene brown bears that each inhabited multiple geographically proximate caves in northern Spain. In cave bears, we find that, although most caves were occupied simultaneously, each cave almost exclusively contains a unique lineage of closely related haplotypes. This remarkable pattern suggests extreme fidelity to their birth site in cave bears, best described as homing behaviour, and that cave bears formed stable maternal social groups at least for hibernation. In contrast, brown bears do not show any strong association of mitochondrial lineage and cave, suggesting that these two closely related species differed in aspects of their behaviour and sociality. This difference is likely to have contributed to cave bear extinction, which occurred at a time in which competition for caves between bears and humans was likely intense and the ability to rapidly colonize new hibernation sites would have been crucial for the survival of a species so dependent on caves for hibernation as cave bears. Our study demonstrates the potential of ancient DNA to uncover patterns of behaviour and sociality in ancient species and populations, even those that went extinct many tens of thousands of years ago.

Ancient DNA studies have revolutionized the study of extinct species and populations, providing insights on phylogeny, phylogeography, admixture and demographic history. However, inferences on behaviour and sociality have been far less frequent. Here, we investigate the complete mitochondrial genomes of extinct Late Pleistocene cave bears and middle Holocene brown bears that each inhabited multiple geographically proximate caves in northern Spain. In cave bears, we find that, although most caves were occupied simultaneously, each cave almost exclusively contains a unique lineage of closely related haplotypes. This remarkable pattern suggests extreme fidelity to their birth site in cave bears, best described as homing behaviour, and that cave bears formed stable maternal social groups at least for hibernation. In contrast, brown bears do not show any strong association of mitochondrial lineage and cave, suggesting that these two closely related species differed in aspects of their behaviour and sociality. This difference is likely to have contributed to cave bear extinction, which occurred at a time in which competition for caves between bears and humans was likely intense and the ability to rapidly colonize new hibernation sites would have been crucial for the survival of a species so dependent on caves for hibernation as cave bears. Our study demonstrates the potential of ancient DNA to uncover patterns of behaviour and sociality in ancient species and populations, even those that went extinct many tens of thousands of years ago.

Ancient DNA studies have revolutionized the study of extinct species and populations, providing insights on phylogeny, phylogeography, admixture and demographic history. However, inferences on behaviour and sociality have been far less frequent. Here, we investigate the complete mitochondrial genomes of extinct Late Pleistocene cave bears and middle Holocene brown bears that each inhabited multiple geographically proximate caves in northern Spain. In cave bears, we find that, although most caves were occupied simultaneously, each cave almost exclusively contains a unique lineage of closely related haplotypes. This remarkable pattern suggests extreme fidelity to their birth site in cave bears, best described as homing behaviour, and that cave bears formed stable maternal social groups at least for hibernation. In contrast, brown bears do not show any strong association of mitochondrial lineage and cave, suggesting that these two closely related species differed in aspects of their behaviour and sociality. This difference is likely to have contributed to cave bear extinction, which occurred at a time in which competition for caves between bears and humans was likely intense and the ability to rapidly colonize new hibernation sites would have been crucial for the survival of a species so dependent on caves for hibernation as cave bears. Our study demonstrates the potential of ancient DNA to uncover patterns of behaviour and sociality in ancient species and populations, even those that went extinct many tens of thousands of years ago.

[Resumen] El Oso Pardo (Ursus arctos LINNAEUS 1758) es un úrsido de amplia distribución geográfica que abarca Eurasia y América, aunque en la actualidad sus poblaciones están fragmentadas en pequeños núcleos, sobre todo en Eurasia. En la Península Ibérica perviven dos poblaciones, la cantábrica y la pirenaica, y sólo gracias a los mecanismos de protección establecidos por distintos organismos nacionales y autonómicos. No fue así en el pasado, cuando la especie tenía una distribución más amplia y continua. En este trabajo se estudian los restos fósiles de oso pardo del NW de la península Ibérica (principalmente Galicia y Asturias) procedentes de diversos yacimientos en cavidades cársticas. Las dataciones radiométricas arrojan edades holocenas para la mayor parte de los yacimientos, si bien en Galicia se localizaron restos del Pleistoceno. El estudio métrico de los restos ha servido para la caracterización de los individuos en cuanto a talla, edad y sexo, lo que resulta de interés para las interpretaciones posteriores sobre su paleobiología. En líneas generales se observa que la talla de los individuos holocenos es mayor que en los osos actuales de la misma zona geográfica. Mediante el estudio de isótopos estables en colágeno óseo se determina el tipo de dieta de los individuos estudiados, ya que al tratarse de un animal omnívoro y oportunista, se da la posibilidad de que las diferencias observadas en la talla vengan producidas por diferencias en la alimentación. Sin embargo del estudio isotópico se concluye que ésta no ha variado sustancialmente, y las pequeñas diferencias en valores isotópicos se deben más a particularidades individuales como edad, área geográfica y otros parámetros ambientales. Finalmente, del estudio de secuencias de ADN mitocondrial de los individuos estudiados y otras disponibles en la literatura se observa que, a diferencia de lo que algunos autores habían propuesto, la Península Ibérica no parece haber sido un refugio durante el último máximo, [Abstract]The brown bear (Ursus arctos LINNAEUS 1758) is an ursid with a broad geographic distribution covering Eurasia and America, although currently its populations are fragmented in small groups, especially in Eurasia. Two populations, the Cantabrian and the Pyreneean ones, survive at present in the Iberian Peninsula, and only thanks to the protection mechanisms established by various national and regional agencies. Not so in the past, when the species had a wider and continuous distribution. In this thesis the fossil brown bear from NW of the Iberian Peninsula (mainly Galicia and Asturias) from various sites in karst cavities are studied. Radiometric dating yielded Holocene age for most of the deposits, although in Galicia some Pleistocene remains were found. The metric study of the remains served to characterize the individuals in terms of size, age and sex, which is of interest for subsequent interpretations of their palaeobiology. In general terms, the size of the Holocene individuals is higher than in current bears of the same geographical area. The study of stable isotopes in bone collagen allows to determine the type of diet of the individuals studied, since being an omnivorous and opportunistic animal, exists the possibility that the differences in size were caused by differences in their feeding type. However the isotopic study concludes that it has not substantially changed, and the observed small differences in isotopic values are due more to individual characteristics such as age, geographic area and other environmental parameters. Finally, the study of mitochondrial DNA sequences of these individuals and others available in the literature shows that, unlike what some authors had proposed, the Iberian Peninsula does not seem to have been a refuge during the last glacial maximum for this species, but the pattern of Holocene recolonization is more complex than traditionally assumed.

[EN] In this paper we present 13 new radiocarbon datings of brown bear (Ursus arctos L.) remains from caves of the western half of the Cantabrian Mountains (Galicia, Asturias, Cantabria). This dates, as well as other previously reported, range from more than 40,000 years BP to 2,442 ± 61 years cal BP, belonging mostly to the early Holocene. From a whole of 26 datings, only 3 are of Pleistocene age. In order to complete the distribution in space and time in the Iberian peninsula, we review the literature on this species presence and its chronology by radiocarbon dating or archaeological culture when it exists. The presence of the brown bear has been observed in at least 143 sites. Oldest mentions are from Middle Pleistocene from the south of the Iberian peninsula. In Upper Pleistocene, sites cover the whole peninsula, with only 5 radiocarbon dates. Sites with Pleistocene fossils are a few more than the Holocene ones. There are several problems with the observed distribution. Firstly, as for the vast majority of terrestrial biocenosis, even if the species was present there are not preserved remains. An example of this is the lack of Holocene remains in places we know it was present according to the historical literature. In general, there are gaps in the distribution that coincide with no limestone lithology. Furthermore, there is a bias related to the intensity of research in certain areas. It was suggested that brown bear population increased when cave bear (Ursus spelaeus ROSENMÜLLER) wiped out, but only in 12.5 % of the places in which both species are present is possible to see a substitution. The number of brown bears in every site is low before and after the extinction of its alleged competitor. Our results suggest that the denning ecology was different from the cave bear and, like nowadays, brown bears used different types of dens, like holes in the ground, inside trees or smaller natural caves. In the XVI century the population begins to decrease, till reachi, [ES] Se presentan los resultados de 12 nuevas dataciones radiométricas 14C de restos de oso pardo (Ursus arctos L.) procedentes de cuevas de la mitad occidental de la Cordillera Cantábrica (Galicia-Asturias-Cantabria). Estas dataciones, además de otras previamente publicadas, datan la presencia de la especie en cuevas de esta zona desde hace más de 40.000 años BP a 2.442 ± 61 años cal BP, correspondiendo la mayor parte a los inicios del Holoceno. La revisión bibliográfica, realizada sobre la presencia de esta especie en otros yacimientos de la Península, muestra la existencia de estos en al menos 143 sitios. En el Pleistoceno Superior los yacimientos se distribuyen por toda la Península y superan en número a aquellos con restos holocenos. En general se producen vacíos en la distribución coincidentes con las zonas de litología no caliza. También, existe un sesgo relacionado con la intensidad de la investigación en ciertas áreas. Otro factor puede ser la competencia con el oso cavernario (Ursus spelaeus ROSENMÜLLER) por recursos o hábitat, aunque sólo el 12,5% de los yacimientos en donde aparecen las dos especies muestran la sustitución de una especie por la otra tras la extinción del oso cavernario. El descenso de población en oso pardo se refleja en la escasez de yacimientos a partir del Neolítico, probablemente debido a la presión ejercida por la expansión de las actividades humanas, hasta llegar a las dos poblaciones actuales relictas en la Península Ibérica (Cordillera Cantábrica y Pirineos).

[Resumen] El Oso Pardo (Ursus arctos LINNAEUS 1758) es un úrsido de amplia distribución geográfica que abarca Eurasia y América, aunque en la actualidad sus poblaciones están fragmentadas en pequeños núcleos, sobre todo en Eurasia. En la Península Ibérica perviven dos poblaciones, la cantábrica y la pirenaica, y sólo gracias a los mecanismos de protección establecidos por distintos organismos nacionales y autonómicos. No fue así en el pasado, cuando la especie tenía una distribución más amplia y continua. En este trabajo se estudian los restos fósiles de oso pardo del NW de la península Ibérica (principalmente Galicia y Asturias) procedentes de diversos yacimientos en cavidades cársticas. Las dataciones radiométricas arrojan edades holocenas para la mayor parte de los yacimientos, si bien en Galicia se localizaron restos del Pleistoceno. El estudio métrico de los restos ha servido para la caracterización de los individuos en cuanto a talla, edad y sexo, lo que resulta de interés para las interpretaciones posteriores sobre su paleobiología. En líneas generales se observa que la talla de los individuos holocenos es mayor que en los osos actuales de la misma zona geográfica. Mediante el estudio de isótopos estables en colágeno óseo se determina el tipo de dieta de los individuos estudiados, ya que al tratarse de un animal omnívoro y oportunista, se da la posibilidad de que las diferencias observadas en la talla vengan producidas por diferencias en la alimentación. Sin embargo del estudio isotópico se concluye que ésta no ha variado sustancialmente, y las pequeñas diferencias en valores isotópicos se deben más a particularidades individuales como edad, área geográfica y otros parámetros ambientales. Finalmente, del estudio de secuencias de ADN mitocondrial de los individuos estudiados y otras disponibles en la literatura se observa que, a diferencia de lo que algunos autores habían propuesto, la Península Ibérica no parece haber sido un refugio durante el último máximo, [Abstract]The brown bear (Ursus arctos LINNAEUS 1758) is an ursid with a broad geographic distribution covering Eurasia and America, although currently its populations are fragmented in small groups, especially in Eurasia. Two populations, the Cantabrian and the Pyreneean ones, survive at present in the Iberian Peninsula, and only thanks to the protection mechanisms established by various national and regional agencies. Not so in the past, when the species had a wider and continuous distribution. In this thesis the fossil brown bear from NW of the Iberian Peninsula (mainly Galicia and Asturias) from various sites in karst cavities are studied. Radiometric dating yielded Holocene age for most of the deposits, although in Galicia some Pleistocene remains were found. The metric study of the remains served to characterize the individuals in terms of size, age and sex, which is of interest for subsequent interpretations of their palaeobiology. In general terms, the size of the Holocene individuals is higher than in current bears of the same geographical area. The study of stable isotopes in bone collagen allows to determine the type of diet of the individuals studied, since being an omnivorous and opportunistic animal, exists the possibility that the differences in size were caused by differences in their feeding type. However the isotopic study concludes that it has not substantially changed, and the observed small differences in isotopic values are due more to individual characteristics such as age, geographic area and other environmental parameters. Finally, the study of mitochondrial DNA sequences of these individuals and others available in the literature shows that, unlike what some authors had proposed, the Iberian Peninsula does not seem to have been a refuge during the last glacial maximum for this species, but the pattern of Holocene recolonization is more complex than traditionally assumed.

[Resumen] En este trabajo se presentan 73 secuencias cortas de ADN mitocondrial (ADN mt) obtenidas a partir de 30 muestras de oso pardo (Ursus arctos) y 56 de oso cavernario (Ursus spelaeus) procedentes de diversos yacimientos del noroeste de la Península ibérica (Galicia y Asturias) y de edades finipleistocenas y holocenas. La técnica utilizada fue la amplificación mediante PCR de pequeños fragmentos de ADNmt y la posterior secuenciación Sanger de los productos PCR. En total se han obtenido 6 haplotipos diferentes para el oso pardo y dos para el cavernario. El elevado porcentaje de éxito de las amplificaciones PCR (85%, 73 amplificaciones positivas de un total de 86 muestras) demuestra las buenas condiciones de las cuevas de la Sierra do Courel para la preservación de ADN en restos óseos fósiles, incluso de decenas de milenios de antiguedad, [Abstract] In this paper we present 73 short mitochondrial DNA (mtDNA) sequences obtained from 30 brown bear (Ursus arctos) and 56 cave bear (Ursus spelaeus) samples in several cave sites of Northwestern Iberian Peninsula (Galicia and Asturias), of Holocene and Pleistocene ages. The technique used was PCR amplification of small mtDNA fragments and the subsequent Sanger sequencing of PCR products. In total, 6 different haplotypes were obtained for the brown bear and two for the cave bear. The high success rate of PCR amplifications (85%, 73 positive amplifications out of a total of 86 samples) demonstrates the good conditions of the Sierra do Courel caves for the preservation of DNA in fossil bone remains, even for tens of millennia old.