Aitziber Suárez-Bilbao

Paleoenvironmental and Paleoclimatic Approach to the Upper Pleistocene Site of Artazu Vii (Arrasate, Northern Iberian Peninsula) Using Small Vertebrates

Abstract. 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.

A large mammal assemblage during MIS 5c: Artazu VII (Arrasate, northern Iberian Peninsula)

Abstract Artazu VII palaeontological site (Arrasate, Gipuzkoa) is one of the few deposits in the Iberian Peninsula in which humans did not intervene in its formation as the site acted as a natural trap. The vertebrate remains recovered are in a very good state of preservation and display great biodiversity. The large mammal assemblage from Artazu VII is studied in detail in this paper. Fourteen different species are described, including ungulates and carnivores. Morphological and osteometric descriptions are also provided, as well as a morphological study of chamois and leopard compared with the same species of similar chronology both in the surroundings of the site and in the rest of the Iberian Peninsula. The existence of biases related to the form of the shaft is tested, as these might relativize the value of the remains as a representative proxy of the fauna in the early Late Pleistocene in the Iberian Peninsula. The palaeoecology inferred from this association indicates the existence of a woodland mass alternating with meadow biotope, and with a watercourse in the surrounding area.

The Late Pleistocene avifauna from Artazu VII (Basque Country, northern Iberian Peninsula)

ABSTRACT This study is a contribution to the knowledge of ancient avifauna in the Iberian Peninsula. 1,786 bird bones have been recovered from Artazu VII (Arrasate, northern Iberian Peninsula), with 239 remains identified to Order/Family and 519 to Genus/Species level, belonging to, at least, 12 taxa: Buteo lagopus, Aquila chrysaetos, Perdix perdix, Coturnix coturnix, Alectoris sp., Lyrurus tetrix, Crex crex, Bubo cf. bubo, Corvus monedula, Pica pica, Pyrrhocorax pyrrhocorax and Pyrrhocorax graculus. The best represented taxa are corvids, followed by L. tetrix. The most significant finding is the presence of B. lagopus, which represents the second fossil record in the Iberian Peninsula. The morphometric analyses performed for C. coturnix and L. tetrix contribute to the knowledge of those taxa measurements, due to the Artazu VII assemblage being one of the best samples of these taxa in the Iberian Peninsula for the late Pleistocene. All the measurements of B. lagopus and C. coturnix have been analysed statistically. A brief taphonomic study has been carried out to identify the bird accumulation agent. Finally, a palaeoenvironmental analysis is based on the bird assemblage and ecology, and this new information is compared to palaeoenvironmental data inferred from vertebrates at Artazu VII in previous studies.

BENTHIC FORAMINIFERA AND OSTRACODA FROM MIDDLE–UPPER MIOCENE SEQUENCES OF SOUTHERN ECUADOR

Abstract. The debate regarding a possible marine influence during the middle—late Miocene in the Loja, Malacatos-Vilcabamba and Catamayo-Gonzanamá Basins (southern Ecuador) continues. To shed light on this controversy, we present a detailed stratigraphic and micropaleontological (benthic foraminifers and ostracods) study of selected sections from these basins. The facies associations, together with the presence of several benthic foraminifer species from marginal marine and open-water environments and ostracod genera resistant to high salinity changes, verify a marine water influence and sporadic marginal marine conditions in this area during certain periods of the middle—late Miocene. Additionally, six new ostracod species are hereby described: Heterocypris ballentae, Cyprideis lojaensis, Cyprideis petersonae, Cyprideis pachamama, Cyprideis tumi and Cyprideis amaru.

ASOCIACIONES DE OSTRÁCODOS DEL MIOCENO TEMPRANO-MEDIO DE LOMA NEGRA (BARDENAS REALES DE NAVARRA, CUENCA DEL EBRO): EVOLUCIÓN PALEOAMBIENTAL DE UN MEDIO LACUSTRE

Abstract. LOWER—MIDDLE MIOCENE OSTRACOD ASSEMBLAGES OF LOMA NEGRA (BARDENAS REALES DE NAVARRA, EBRO BASIN): PALAEOENVIRONMENTAL EVOLUTION OF A LACUSTRINE SYSTEM. The palaeoenvironmental evolution of the Loma Negra section (Bardenas Reales de Navarra, Ebro Basin) during the lower—middle Miocene, is studied for the first time. The paleoenvironmental interpretation is based on the recovered ostracod assemblages and the sedimentology. The lower part of this section is composed by red, yellow and grey mudstones, and with Paralimnocythere sp. as the most abundant ostracod taxon. The lithological features and the faunistic assemblage allows the interpretation of a paleoenvironment with the development of shallow water bodies with stagnant, warm and fresh to oligohaline waters in distal alluvial flood plains for this section. The presence of some sandstone levels where the most abundant ostracod species is Cyclocypris laevis (Müller) marks punctual higher energy events inside this alluvial system and the presence of more saline waters. The upper part of the section is formed by grey limestones with interbedded fine grey mudstones. In this interval, Pseudocandona parallela Müller is the most abundant ostracod species, indicating the development of a stable lacustrine system with water currents, and temperate to cold and oligohaline to mesohaline waters. The transition between the alluvial and the lacustrine systems shows a gradual evolution.