Continental gastropods from Late Pleistocene to basal Holocene from Urtiaga (Deba, Gipuzkoa)

The Urtiaga cave is an archaeological site with a record from the Solutrean to the Azilian periods. At the site, there are numerous remains of molluscs accumulated, both marines and continentals. The presence of marine gastropods is associated to human consume. In this work the association of continental gastropods is presented, which is constituted by the species Xerosecta arigonis, Oxychilus sp., Discus rotundatus, Clausilia bidentata, Obscurella obscurum, Granaria braunii, Chondrina avenacea and Pomatias elegans. Given its small size, the hypothesis that these gastropods were accumulated as foodstuff is discarded. All species represented in the site are indicatives of humid and wooded zones. This fact would explain that the richest and most diverse levels coincide with the humid and warm moment of the AzilianLa cueva de Urtiaga es un yacimiento arqueológico con un registro desde el Solutrense hasta el Aziliense. En el yacimiento hay numerosos restos de moluscos acumulados, tanto continentales como marinos. La presencia de gasterópodos marinos está relacionada con el consumo humano y con el uso de los mismos como adornos, mientras que la acumulación de gasterópodos continentales, debido a su pequeño tamaño, no fue generada por humanos. La asociación de gasterópodos continentales está compuesta por las especies Xerosecta arigonis, Oxychilus sp., Discus rotundatus, Clausilia bidentata, Obscurella obscurum, Granaria braunii, Chondrina avenacea y Pomatias elegans. Todas las especies representadas en el yacimiento son indicadoras de zonas húmedas y boscosas, coincidiendo los niveles más ricos y diversos con el momento cálido y húmedo del Aziliens

Mineralogical analysis of the clays of Lower-Middle Miocene transition in Loma Negra section (Bardenas Reales de Navarra, Ebro Basin)

A continuous succession of Lower and Middle Miocene continental sediments, ranging from 20.5 to 15.5 Ma, crops out in the Natural Park of Bardenas Reales de Navarra. The good characteristics of the outcrops has favoured numerous studies in the area in order to reconstruct the palaeoenvironmental conditions between the Ramblian and Aragonian, where the beginning Miocene Climatic Optimum is included. This work presents the first results of mineralogical study in the Loma Negra section, which previously has been subject of palaeontological studies. Total rock analyses show that mineralogy reflects changes previously established from lithologic criteria, suggesting an evolution from a distal alluvial environment to the establishment of a shallow lacustrine environment. The clay mineralogy indicates constant environmental conditions in the series, except for the samples LN-64a and b, with a high value of smectite perhaps representing a semiarid environment characterized by short rainy season compared to dry environment represented by illite and chloriteEn el Parque Natural de Las Bardenas Reales de Navarra aflora una serie casi continua de los sedimentos continentales del Mioceno inferior y medio, abarcando desde 20,5 hasta 15,5 Ma. La buena calidad de los afloramientos ha propiciado que en la zona se hayan realizado numerosos estudios con el fin de reconstruir las condiciones paleoambientales entre el Rambliense y el Aragoniense, en el cual se incluye el comienzo del Óptimo Climático del Mioceno. En este trabajo se presentan los primeros resultados del estudio mineralógico de la sección de Loma Negra, que anteriormente ya ha sido objeto de estudios paleontológicos. Los análisis de roca total muestran que la mineralogía refleja los cambios previamente establecidos a partir de criterios litológicos, que marcan una evolución desde un medio aluvial distal hasta la instauración de un medio lacustre somero. La mineralogía de arcillas indica unas condiciones secas poco cambiantes representadas por la illita y la clorita, con excepción de las muestras LN-64a y b, en los que el alto valor de esmectita pudiera indicar un ambiente semiárido caracterizado por una corta estación de lluvia

Preliminary study of the ostracods from the Lower Eocene Loza site (Álava, Basque-Cantabrian Basin)

In this paper the preliminary study of ostracods preserved in a distinct fossiliferous level within the poorly-known lower Eocene lacustrine-palustrine succession of Loza (Álava, Basque-Cantabrian Basin) is developed. The studied level is a 28cm thick marly interval including a thin whitish chalky level, interbedded between fine-grained limestones with variable proportions of gastropods and characean remains.With the aim of knowing the richnes of the ostracods and the prevailing palaeoenvironmental conditions during deposition of the lacustrine succession, two samples (L1 and L2), located within the marly interval respectively below and above the chalky level, have been studied. In L1 the most abundant genus is Limnocythere Brady, while in L2 the principal genera are Limnocythere and Cyclocypris Brady and Norman. According to the successive change in the ostracods, the fossiliferous level was deposited in a lacustrine environment,which was more saline and, probably, restricted over timeEn este trabajo se desarrolla un estudio preliminar de los ostrácodos preservados en un nivel fosilífero distintivo dentro de la pobremente conocida sucesión de origen palustre-lacustre del Eoceno inferior de Loza (Álava, Cuenca Vasco-Cantábrica). El nivel estudiado contiene un espesor de 28cm de margas incluyendo una fina banda calcítica blanca, intercalada entre calizas de grano fino con proporciones variables de gasterópodos y carofitas. Con el propósito de conocer la riqueza de ostrácodos y las condiciones paleoambientales predominantes durante el depósito de la sucesión lacustre, se han estudiado dos muestras (L1 y L2), situadas respectivamente por encima y por debajo de la banda blanca. En L1 el género más abundante es Limnocythere Brady, mientras que en L2 los géneros mayoritarios son Limnocythere y Cyclocypris Brady y Norman. De acuerdo a la variación de los ostrácodos identificados, el nivel fosilífero se depositó en un medio lacustre que fue más salino y, posiblemente, restringido con el tiemp

Palaeoenvironmental analysis based on alluvial ostracod assemblages of the Cenicero section (lower Miocene, NW Ebro Basin)

In this work we perform for the first time a palaeoenvironmental and biostratigraphic analysis of the lower Miocene alluvial deposits of the Cenicero section (NW sector of the Ebro Basin; N Iberian Peninsula), based on the ostracod and micromammal assemblages. One of the main characteristics of this section is the unusual abundance on non-reworked ostracods present in the studied samples compared to other European sequences of similar age and sedimentary environment. This fact has allowed us to develop precise palaeoenvironmental reconstructions. The variations of the identified ostracod assemblages, defined by species such as Cyclocypris laevis, Ilyocypris bradyi, Ilyocypris gibba, Limnocythere sp. or Pseudocandona parallela, record the development of small, ephemeral and shallow ponds in a distal alluvial and/or floodplain environment. Towards the upper part of the section the ponds appear to be less ephemeral, being the aquatic systems more stable for ostracods development. Variations in the water temperature and salinity have been observed along the section, which are related to changes in the local pluviometric regime. On the other hand, the presence of micromammals in one of the studied samples has allowed the precise dating of this section. Thus, the presence of Armantomys daamsi dates the Cenicero section as Agenian (lower Miocene), local zone Y2 (MN2)

Study of the small mammals of Bronze Age layers from Arenaza I Cave (Galdames, Bizkaia)

Este trabajo recoge el estudio de los micromamíferos de los lechos superiores (ca. 3695-4414 cal BP) de la Cueva de Arenaza I (Galdames, Bizkaia), excavados entre 1991 y 1993 y recuperados recientemente del depósito provincial. El conjunto de restos corresponde al menos a 14 especies diferentes de micromamíferos, nueve de ellas pertenecientes al Orden Rodentia y cinco al Orden Eulipotyphla. Los datos paleoecológicos de los tres lechos indican un claro predominio de masas forestales, siendo el lecho 9 en el que mayor extensión presentan. Por ende, probablemente es en ese momento cuando tendrían lugar las condiciones ambientales más cálidas y húmedas de todo el registroThe study of the small mammals from the uppermost layers (ca. 3695- 4414 cal BP) from Arenaza I Cave (Galdames, Bizkaia) is reported in this paper. Even if the archaeological works were carried out between 1991 and 1993, the sediment has been recovered from the provincial deposit. A total of 14 species have been identified, nine belonging to the Order Rodentia and five to Order Eulipotyphla. Palaeoecological data obtained for the three layers indicate a clear predominance of forest, being the layer 9 where it was most extended. Therefore it was probably at that time when the most humid conditions and mild temperatures took plac

A new Late Pleistocene non-anthropogenic vertebrate assemblage from the northern Iberian Peninsula: Artazu VII (Arrasate, Basque Country)

Late Pleistocene palaeontological sites without human intervention are limited in the Cantabrian region, and even more so those with a good state of preservation and rich biodiversity. A new vertebrate fossiliferous locality discovered at Kobate Quarry (Arrasate, northern Iberian Peninsula) is presented in this article. This site, in which remains of 40 different vertebrate taxa were accumulated, acted as a natural trap. The preliminary vertebrate faunal list includes five amphibian taxa, four reptiles, seven species of birds and 24 mammalian taxa. While small mammals are represented by 13 small mammal taxa (seven in the Order Rodentia, five in the Order Eulipotyphla, and one in the Order Chiroptera), the large mammal fauna comprises eleven species, including ungulates and carnivores. The palaeoecology inferred from this faunal assemblage suggests the existence of large forested areas with some grassland and a watercourse nearby, within a notably warm and humid climate. These palaeoenvironmental conditions, combined with AMS and AAR results carried out in macrofaunal bone samples, suggest that the deposit from Artazu VII would be located in the first half of the Late Pleistocene, in the Marine Isotope Stage (MIS) 5c. Résumé Les gisements paléontologiques de la fin du Pléistocène sont limités dans la région Cantabrique, et encore plus limités sont les sites ayant fourni des restes osseux en bon état de conservation et montrant une grande biodiversité. Nous présentons ici un nouveau site trouvé dans la carrière de Kobate (Arrasate, Nord de la péninsule Ibérique). Ce site a certainement agi comme un piège naturel et contient une accumulation de restes appartenant à 40 espèces différentes de vertébrés. La liste préliminaire de la faune de vertébrés comprend cinq taxons d’amphibiens, quatre de reptiles, sept espèces d’oiseaux et 24 taxons de mammifères. Alors que les mammifères sont représentés par 13 taxons de micromammifères (sept appartiennent à l’ordre Rodentia, cinq à l’ordre Eulipothypla, et un à l’ordre Chiroptera), les grands mammifères sont représentés par onze espèces, y compris des ongulés et des carnivores. Cette association faunique suggère un paléoenvironnement caractérisé par de vastes étendues boisées avec quelques prairies et un cours d’eau à proximité, dans un climat particulièrement chaud et humide. Ces conditions paléoenvironnementales, combinées à des datations AMS et AAR à partir d’échantillons d’os de la macrofaune, permettent de localiser le gisement d’Artazu VII dans la première moitié du Pléistocène supérieur, et plus précisement dans le stade isotopique marin (MEI) 5c

Late Pleistocene vertebrate assemblages from Artazu VII and Artazu VIII sites (Arrasate, northern Iberian Peninsula): palaeobiology and palaeoecology

293 p.The Late Pleistocene was a period characterized by numerous climatic fluctuations that occurred in millennial scale alternating cold and warm moments. Unfortunately, Late Pleistocene palaeontological sites without human intervention are limited in the Iberian Peninsula, and even more those with good state of preservation and rich taxa diversity. Thus, two new vertebrate fossiliferous localities are presented in this thesis: Artazu VII and Artazu VIII. Both sites were discovered after a blasting at Kobate Quarry (Arrasate, northern Iberian Peninsula). The good integrity and good state of preservation of large mammal bones, as well as the lack of anthropological or predator activity, discarded the possibility of an anthropogenic origin for both sites.This thesis constitutes a compilation of different types of studies, all of them focused on the reconstruction and evolution of the environment during Late Pleistocene. The stratigraphic sequence has been correlated to Marine Isotopic Stages (MIS), taking into account Radiocarbon (AMS) and Amino Acid Racemization (AAR) datings and the palaeoenvironmental variations inferred from the small vertebrates community. In addition, we compare these results with the information available for the same periods at other sites in the Iberian Peninsula.- Artazu VII site was discovered in 2012 and excavated in 2013 by an emergency excavation. There were no clear stratigraphic sequence or levels, and AMS and ARR datings situated the site in ~ 93 ka BP. The fossiliferous record (small mammals, amphibians, reptiles, ungulates, carnivores and birds) suggested the existence of large forested areas with some grassland and a water course nearby, within a notably warm and humid climate. Indeed, regarding woodland expansion and retraction, four climatic main phases were observed. These palaeoenvironmental conditions, combined with dating results, suggest that the deposit from Artazu VII would be located in the first half of the Late Pleistocene, in the MIS 5c.- Artazu VIII site was found in 2013 and the excavation was carried out in the following two years. Based on sedimentological features, 12 levels were differentiated along the sequence. According to AMS and ARR datings, the sedimentary fill was a continuous succession that comprises, at least, 36 ka of the late Pleistocene. The small and large mammal assemblages and the preserved bird community, as well as the mineralogical and sedimentological studies, allowed the approach to the palaeoclimatic conditions and the evolution and sedimentary fill origin of this cave. Three palaeoenvironmental and palaeoclimatic stages were differentiated and correlated to NGRIP 18O curve, from MIS 5c to MIS 4

Biometry of Soricidae lower dental elements from the late Pleistocene site of Artazu Vil (Arrasate> Gipuzkoa)

En este trabajo se presenta el estudio biométríco realizado en los sonados del yacimiento del Pleistoceno superior de Artazu Vil (Arrasate, Gipuzkoa). Se han m edido 97 elementos dentarios inferiores conectados a las mandíbulas de las especies Sorex araneus-coronatus y Sorex minutus. De esta manera se ha podido determinar la variabilidad en tamaño de los dientes inferiores en estas especies presentes en Artazu Vil. Además, este análisis ha posibilitado la clasificación de las piezas dentarias aisladas que se han encontrado en este yacimientoIn this work we present the biometry study carried out in soricids from the late Pleistocene site of Artazu VII (Arrasate, Gipuzkoa). A total of 97 lower teeth connected to a mandible of Sorex araneus-coronatus and Sorex minutus have been measured. In this way, it has been determined the variability of lower teeth size of thes especies presented in Artazu VII. Moreover, this analysis makes possible the classification of isolated dental elements found in this sit

Análisis mineralógico de las arcillas del tránsito Mioceno inferior-medio en la sección Loma Negra (Bardenas Reales de Navarra, Cuenca del Ebro)

En el Parque Natural de Las Bardenas Reales de Navarra aflora una serie casi continua de los sedimentos continentales del Mioceno inferior y medio, abarcando desde 20,5 hasta 15,5 Ma. La buena calidad de los afloramientos ha propiciado que en la zona se hayan realizado numerosos estudios con el fin de reconstruir las condiciones paleoambientales entre el Rambliense y el Aragoniense, en el cual se incluye el comienzo del Óptimo Climático del Mioceno. En este trabajo se presentan los primeros resultados del estudio mineralógico de la sección de Loma Negra, que anteriormente ya ha sido objeto de estudios paleontológicos. Los análisis de roca total muestran que la mineralogía refleja los cambios previamente establecidos a partir de criterios litológicos, que marcan una evolución desde un medio aluvial distal hasta la instauración de un medio lacustre somero. La mineralogía de arcillas indica unas condiciones secas poco cambiantes representadas por la illita y la clorita, con excepción de las muestras LN-64a y b, en los que el alto valor de esmectita pudiera indicar un ambiente semiárido caracterizado por una corta estación de lluvias.Departamento de Estratigrafía y Paleontología, Universidad del País Vasco, EspañaDepartamento de Mineralogía y Petrología, Universidad del País Vasco, EspañaUnidad de Zaragoza, Instituto Geológico y Minero de España, Españ

Paleoenvironmental and Paleoclimatic approach to the Late Pleistocene site of Artazu (Arrasate, Northern Iberian Peninsula) using small vertebrates

The Artazu VII site (Arrasate, northern Iberian Peninsula) is a fossiliferous deposit that was discovered unsystematically at the Kobate Quarry in 2012. During the following year, all the vertebrate remains attributed to the upper Pleistocene (~ 93 ka) were recovered in an emergency excavation project. Here, we describe, for the first time, the small vertebrate assemblage (amphibians, reptiles, and small mammals) recovered from the site, as well as the environmental and climatic results estimated from the paleoecological affinities of the studied taxa. More than 50,000 microvertebrate elements were recovered, comprising 24 taxa of which seven belong to the Order Rodentia; five, to the Order Eulipotyphla; one, to the Order Chiroptera; seven, to the Order Anura; and four, to the Order Squamata. Considering the environmental attributions and the relative abundance of each taxon, the paleoenvironmental and paleoclimatic conditions were reconstructed and the sequence was divided into three phases. Although woodland mass is present in the whole sequence, expansion and regression changes can be observed. Thus, the stratigraphic sequence begins with a landscape with open spaces. Higher up the stratigraphic column, woodland expands and reaches its maximum development in the second phase. Finally, the woodland environment declines and reaches similar values to those of the initial situation. These forestry biotopes were related to temperate and humid conditions comparable to those of the modern landscape. It was also concluded that a watercourse existed near the site.The study presented in this paper was partially funded by the research project of the Spanish Science Ministry HAR2014-53536-P and by the Research Teams GIU12/35 and GIU15/34 at the University of the Basque Country. Aitziber Suárez-Bilbao enjoys a pre-doctoral fellowship from the Basque Government (PRE_2014_1_345)