Luis Angel Ortega

The First Occurrence in the Fossil Record of an Aquatic Avian Twig-Nest with Phoenicopteriformes Eggs: Evolutionary Implications

Background We describe the first occurrence in the fossil record of an aquatic avian twig-nest with five eggs in situ (Early Miocene Tudela Formation, Ebro Basin, Spain). Extensive outcrops of this formation reveal autochthonous avian osteological and oological fossils that represent a single taxon identified as a basal phoenicopterid. Although the eggshell structure is definitively phoenicopterid, the characteristics of both the nest and the eggs are similar to those of modern grebes. These observations allow us to address the origin of the disparities between the sister taxa Podicipedidae and Phoenicopteridae crown clades, and traces the evolution of the nesting and reproductive environments for phoenicopteriforms. Methodology/Principal Findings Multi-disciplinary analyses performed on fossilized vegetation and eggshells from the eggs in the nest and its embedding sediments indicate that this new phoenicopterid thrived under a semi-arid climate in an oligohaline (seasonally mesohaline) shallow endorheic lacustine environment. High-end microcharacterizations including SEM, TEM, and EBSD techniques were pivotal to identifying these phoenicopterid eggshells. Anatomical comparisons of the fossil bones with those of Phoenicopteriformes and Podicipediformes crown clades and extinct palaelodids confirm that this avian fossil assemblage belongs to a new and basal phoenicopterid. Conclusions/Significance Although the Podicipediformes-Phoenicopteriformes sister group relationship is now well supported, flamingos and grebes exhibit feeding, reproductive, and nesting strategies that diverge significantly. Our multi-disciplinary study is the first to reveal that the phoenicopteriform reproductive behaviour, nesting ecology and nest characteristics derived from grebe-like type strategies to reach the extremely specialized conditions observed in modern flamingo crown groups. Furthermore, our study enables us to map ecological and reproductive characters on the Phoenicopteriformes evolutionary lineage. Our results demonstrate that the nesting paleoenvironments of flamingos were closely linked to the unique ecology of this locality, which is a direct result of special climatic (high evaporitic regime) and geological (fault system) conditions.

Combining Small-Vertebrate, Marine and Stable-Isotope Data to Reconstruct Past Environments

Three very different records are combined here to reconstruct the evolution of environments in the Cantabrian Region during the Upper Pleistocene, covering ~35.000 years. Two of these records come from Antoliñako Koba (Bizkaia, Spain), an exceptional prehistoric deposit comprising 9 chrono-cultural units (Aurignacian to Epipaleolithic). The palaeoecological signal of small-vertebrate communities and red deer stable-isotope data (δ13C and δ15N) from this mainland site are contrasted to marine microfaunal evidence (planktonic and benthic foraminifers, ostracods and δ18O data) gathered at the southern Bay of Biscay. Many radiocarbon dates for the Antoliña’s sequence, made it possible to compare the different proxies among them and with other well-known North-Atlantic records. Cooling and warming events regionally recorded, mostly coincide with the climatic evolution of the Upper Pleistocene in the north hemisphere.

Succession and stable isotope composition of gastropods in Holocene semi-arid alluvial sequences (Bardenas Reales, Ebro Basin, NE Spain): Palaeoenvironmental implications

Three alluvial units, ranging from the middle to late Holocene in age, were distinguished in Bardenas Reales Natural Park (Ebro Basin, NE Spain) based on morphosedimentary analysis and radiocarbon data. In this sensitive Mediterranean alluvial system, the succession and isotopic composition of gastropods greatly contribute to establishing the prevailing palaeoenvironmental conditions. The oldest unit (4763±87 to 2848±55 cal. yr BP) represents fluvial channels and swamped areas, includes the greatest proportion of aquatic gastropods (Ancylus fluviatilis and Lymnaea truncatula) and marsh species (Vallonia pulchella) and presents the most negative values of δ18O (mean −2.21‰ PDB). The intermediate unit (1403±60 to 836±65 cal. yr BP) shows a high rate of alluvial activity related to irregular torrential rainfall, with sedimentary features of aridity, and this unit includes only dry open ground gastropods (Xeroplexa sp., Chondrinidae indet. and Granopupa granum) and presents the least negative values of δ18O (mean −1.17‰ PDB). The youngest unit (191±97 to 127±82 cal. yr BP) exhibits a recurrence of flooding events, mostly includes marsh (Truncatellina callicratis and Lauria cylindracea) and aquatic (Lymnae truncatula) species and shows a very heterogeneous isotopic signal, with −1.83‰ PDB as the mean value of δ18O. As a consequence, a palaeoenvironmental pattern comprised of an early wetter/colder phase followed by a warmer/drier period and, finally, an increase in both cold conditions and hydrological variability, is deduced for the middle to late Holocene in the Ebro Basin. Gastropod shell δ13C values, related to vegetation, can also be linked to palaeoenvironmental changes. The succession and stable isotope composition of gastropods in alluvial sequences are revealed as very sensitive indicators of rapid Holocene climatic changes in fragile semi-arid landscape systems.

Isotope analyses to explore diet and mobility in a medieval Muslim population at Tauste (NE Spain)

The Islamic necropolis discovered in Tauste (Zaragoza, Spain) is the only evidence that a large Muslim community lived in the area between the 8th and 10th centuries. A multi-isotope approach has been used to investigate the mobility and diet of this medieval Muslim population living in a shifting frontier region. Thirty-one individuals were analyzed to determine δ15N, δ13C, δ18O and 87Sr/86Sr composition. A combination of strontium and oxygen isotope analysis indicated that most individuals were of local origin although three females and two males were non-local. The non-local males would be from a warmer zone whereas two of the females would be from a more mountainous geographical region and the third from a geologically-different area. The extremely high δ15N baseline at Tauste was due to bedrock composition (gypsum and salt). High individual δ15N values were related to the manuring effect and consumption of fish. Adult males were the most privileged members of society in the medieval Muslim world and, as isotope data reflected, consumed more animal proteins than females and young males.

PALAEOENVIRONMENT CHANGES ANALYSIS USING PROGRAMMING TECHNIQUES: OSTRACODS ASSEMBLAGE AS CLIMATIC PROXY

The aim of the work is to design some computer activities based on common geological problems. During the last years, geology grade students as well as teacher feels dissatisfaction in “Introduction to Computation” subject. The students don’t understand the requirement of any programming language on their education profile and they do not perceive the programming language as an important skill for geology. To solve this situation, teachers from two different subjects “Introduction to Computation” and “Complements of Geology”, analyzed the problem and decided to propose new laboratory activities in the context of real geological situations. The proposed activity was developed in three stages. First, the real geological problem was explained by the “Complements of Geology” teacher. Second, the students are introduced by the “Introduction to Computation” teacher to the programming exercise that they will have to solve in order to create a computer tool. Third, and helped by both teachers, the students solve the geological problem using the computer program. The selected activity was the analysis of climate change based on a paleoclimatic proxy. The paleoclimate proxies are physical, chemical and biological materials preserved within geological records that can be analyzed and correlated with climate or environmental parameters in actual times. These data help us to understand how the Earths climate system varied both before and after human alteration of the landscape. In this practice, we propose to the students the usage of ostracod crustaceans as a tool to study palaeoenvironmental changes. The proposed activity includes a palaeoenvironmental study developed at different water pools from Bardenas Reales zone (Navarre, Iberian Peninsula) based on ostracods assemblages’ analysis. The distribution of ostracods is related with physico-chemical parameters of waters (T, salinity, pH or dissolved oxygen) and the sediment characteristics (grain-size, sedimentation rate...). The statement of the problem provides the catalogue of the ostracods species assemblage recognized at the different pools located on different lithological substrates in a geologic map. The students analyze the diversity of ostracod assemblages in each pool and then the variability of species using the Fisher Index, which can be used to group the pools. At the same time, they recognize the relative abundance of a specific ostracod specie in each set and correlate the specific specie with a specific Fisher group. They must observe the map where the pools are located and notice the orientation, the scale and the leyend. They can realize that the pools are located on different lithologies, and as the lithology influences on water physical parameters (salinity, pH ...), the students are induced to discern a possible relationship between the occurrence of specific ostracod species and the lithology and, between the water and the lithology. To obtain the Fisher index of a pool, the students must implement a computer algorithm based on iterative control flow structures. This exercise is a clear example of convergence problems where the student must discern between available iterative control flow structures and different convergence criteria. Once the activity was finished, some students were interviewed in order to obtain their opinion. Most of them showed to be satisfied with the new experience, although pointed that they had certain problems to understand some of the geological concepts.

CLASSIFYING ROCKS: A PRACTICAL EXERCISE TO LEARN PROGRAMMING THROUGH GEOLOGICAL CONCEPTS

The Undergraduate Degree in Geology of the University of the Basque Country contains an “Introduction to Computation” subject that is taught in the first semester of the first course. Students are generally very little interested in this matter, mainly because they think that programming skills are no related to any geological subject they are interested in. In this paper, we discuss the implementation of a new activity in the context of the subject “Introduction to Computation” and focused on increasing the motivation of the students on the programming subject. The activity consists on the development of an exercise which combines programming skills and real geological problems, and it is supervised by a multidisciplinary team of teachers from different knowledge areas: teachers from the subject “Introduction to Computation” (henceforth computing teacher) and teachers from the subject “Complements of Geology” (henceforth geology teacher). The proposed exercise consists of three phases. First, the geology teacher introduces a real geologyrelated problem and explains how could it be resolved. On a second phase, the computing teacher explains how to automatize part of the resolution process in terms of a programming language. On a third phase, and once the students have implemented the algorithmic solution to the problem, they solve real examples of the proposed geological problem using the previously created computing tool. On this last phase, both the geology and computing teachers help the students with any geological or programming related question. The selected geological problem was the Classification of Rocks. The students are presented a classification method based on binary questions (two possible answers, YES/NO) which can be implemented in terms of complex/nested If-Then-Else statements. The exercise introduces some new geological concepts and serves as a test-bed for the programming skills, and the students create a useful computer program that will be finally used to classify a collection of rocks. Some interviews carried out after this experience showed that the students were satisfied with the exercise and that they had gained interest in the programming skills.

Isotopic evidence for the reconstruction of diet and mobility during village formation in the Early Middle Ages: Las Gobas (Burgos, northern Spain)

Strontium, carbon, and nitrogen isotopes of human bone and tooth remains have been used to reconstruct residential mobility and diet of early medieval populations at Las Gobas from the sixth to eleventh centuries. Most non-local individuals correspond to the tenth to eleventh centuries and were mostly women and infants. This residential mobility coincided with the formation of Laño village and the abandonment of artificial cave settlement. Carbon and nitrogen isotope ratios of bone collagen indicate an omnivorous homogenous diet based on terrestrial plant resources, with few animal-derived proteins from livestock. Millet consumption was restricted to an earlier period of time (seventh to ninth centuries); and in later periods (tenth to eleventh centuries), mainly C3 plants such as wheat and barley were consumed. In general, there were no dietary differences between individuals according to sex or age. Sex-related dietary differences have only been observed in the tenth to eleventh centuries, when females consumed a more vegetarian diet and less animal protein. The higher δ15N values in infants reflect the weaning effect, while the differences in δ15N values between young adult men and young adult women can be explained as a physiological factor related to pregnancy or different origins. In a comparison with contemporaneous medieval populations in the northern Iberian Peninsula, both δ13C and δ15N values suggest similar foodstuff resources and diet among Christian and Muslim populations.

State formation in early medieval Castile: craft production and social complexity

The EARMEDCASTILE project, based at the University of the Basque Country, has received funding from the European Unions Horizon 2020 Research and Innovation Programme, Marie Sklodowska-Curie Action (grant agreement 656540); http://earmedcastile.blogspot.com).

KIPUTZ IX: UN CONJUNTO SINGULAR DE CIERVO ROJO (CERVUS ELAPHUS LINNAEUS, 1758) DEL PLEISTOCENO SUPERIOR DE LA PENÍNSULA IBÉRICA

Abstract. KIPUTZ IX: A UNIQUE ENSAMBLE OF RED DEER (CERVUS ELAPHUS LINNAEUS, 1738) FROM THE UPPER PLEISTOCENE OF THE IBERIAN PENINSULA. Kiputz IX is an upper Pleistocene site that has provided the richest set of Cervus elaphus complete remains in the Iberian Peninsula. This paper provides a metric and isotopic study of the postcranial skeleton of the 43 individuals that conform this tafocenosis. The robustness of the distal metacarpus evidences the existence of a clear sexual dimorphism and a small predominance of females respect to males. The stage of dental substitution makes evident that the sample is dominated by sub-adult and juvenile specimens, with a low proportion of juvenile and adult individuals. Application of a variability size index on a group of samples from the middle and upper Paleolithic in the Cantabrian Region do not allow establishing any osteometric relation with geographic and chronological factors. Variations in &dgr;13C values among red deer and reindeer are related to the specialized consumption of different plant types. However, the gradual decline in red deer &dgr;13C values over time may reflect the so-called ‘canopy effect’ impacting the floristic composition. Variations in the &dgr;13C and &dgr;15N values, studied together in red deer show that when climatic conditions were more temperate, humidity was higher in this environment than in de northern Pyrenees. The red deer sample from Kiputz IX constitutes a good basis for comparative studies of red deer populations from the Middle and Upper Pleistocene of Europe.

Osteometric analysis of scapula and humerus for Rangifer tarandus and Cervus elaphus:a contribution to the discrimination Late Pleistocene cervids

Fossil remains of reindeer (Rangifer tarandus) occurring outside their present range are an important indicator of formerly cold climatic conditions, but are easily confused with those of the red deer (Cervus elaphus). The locality of Kiputz IX has yielded one of the best-preserved Late Pleistocene reindeer populations of the southern Pyrenees, occurring in association with Bison priscus and the much more abundant Cervus elaphus. Fossil remains from this site are mostly complete and not affected by human intervention, thus creating the perfect conditions for reliable osteometric analyses. Here, we quantify diagnostic morphological features of the scapula and the humerus of Cervus elaphus and Rangifer tarandus to establish the potential of these bones to aid in interspecific discrimination. In the case of the scapula, the best species discriminator is the ratio of the minimum anteroposterior diameter of the scapular neck and the development of the articular process, while the breadth of the trochlea is the best discriminator in the case of the humerus.