Casas de Fernando Alonso, Spain
Casas de Fernando Alonso, Spain

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Jimenez-Arenas J.M.,University of Granada | Palmqvist P.,Campus Universitario Of Teatinos | Perez-Claros J.A.,Campus Universitario Of Teatinos
Quaternary International | Year: 2011

There is probably no paleoanthropological issue with deeper disagreements than the taxonomic status of the Early-Middle Pleistocene members of the genus Homo One reason could be the difficulty of estimating the relationship between morphological and taxonomic diversity. In an attempt to contribute new evidence to this debate, bootstrapping techniques are used for analyzing the cranial variability of Homo. The results indicate that: (i) the size of the neurocranium relative to the viscerocranium discriminates better among extant hominoid species than skull size; (ii) no cluster of fossil specimens of Homo exceeds the morphological variability of Gorilla gorilla, with the only exception of the one that comprises all members of Homo except modern humans; and (iii) some clusters are taxonomically more consistent than others, as long as they show a range of morphological variability similar to that found in both Pan troglodytes and Homo sapiens. According to these results, three taxa are tentatively suggested for Homo: (i) anatomically modern humans; (ii) an "erectine" morphotype plus Neanderthals; and (iii) a "habiline" cluster. Finally, the results indicate a greater taxonomic affinity for the human population involved in the first dispersal "Out of Africa" with the "habiline" group, which agrees with the early age reported for Dmanisi (1.77 Ma), a Georgian site placed at the gates of Europe. © 2011 Elsevier Ltd and INQUA.


Palmqvist P.,Campus Universitario Of Teatinos | Gonzalez-Donoso J.M.,Campus Universitario Of Teatinos | De Renzi M.,University of Valencia
Quaternary Science Reviews | Year: 2014

Lozano-Fernández etal. (2013a) have recently published a method intended for numerical dating of Early Pleistocene sites, which is based on the assumption of uniform, constant rate increase through time of mean lower molar tooth length of water voles (Mimomys savini) in a number of levels sampled in the stratigraphic sequence of Atapuerca TD site. They suggest that the regression equation obtained in this local section for site chronology on tooth size could be useful for estimating the numerical age of other localities from southwestern Europe. However, in our opinion this biostratigraphic approach has severe conceptual and methodological problems, which discourage its use as a chronometric tool. These problems include that: (1) the logic behind their approach represents a 'fallacy of hasty generalization', because the results obtained for a local section are generalized to all possible stratigraphic sequences; (2) the study is based on tooth measurements from a limited set of samples taken in a single locality, which are represented by small numbers of specimens, cover a short time span and have a high level of age uncertainty; (3) the samples analyzed show small, statistically non-significant differences between their mean tooth length values; (4) the approach assumes a linear-straight, orthoevolutionary model of change at constant, monotonic rate for the apparent trend to increasing tooth size in the M.savini lineage; (5) these changes are better described in the Atapuerca TD section by a random walk, or even by a series of independent events, than by a model of rectilinear change; and (6) the application of this methodology to other localities such as the Orce sites, which preserve the oldest evidence of human presence in Europe, would mean that an equation adjusted within a restricted chronological range (1.01-0.8Ma) is used for extrapolating the ages of sites that are clearly older (~1.4Ma). © 2014 Elsevier Ltd.


Figueirido B.,Campus Universitario Of Teatinos | Palmqvist P.,Campus Universitario Of Teatinos | Perez-Claros J.A.,Campus Universitario Of Teatinos | Dong W.,CAS Institute of Vertebrate Paleontology and Paleoanthropology
Naturwissenschaften | Year: 2011

In this study, landmark-based methods of geometric morphometrics are used for investigating the main aspects of cranial shape transformation in the evolution of the giant panda, Ailuropoda melanoleuca. Specifically, we explore if the highly derived cranial adaptations for bamboo feeding of the living panda were developed early in the panda's lineage. Results obtained show that the overall cranial morphologies of the oldest known panda, the "pygmy" Ailuropoda microta, and the late Pleistocene Ailuropoda baconi are both very similar to that of their closest living relative, A. melanoleuca, which agrees with a previous proposal based on qualitative criteria. However, we also describe several differences between the crania of A. microta, A. baconi, and A. melanoleuca, including the development of the postorbital process, the orientation of the occipital region, and the expansion of the braincase. As a result, the cranial morphology of A. microta shows a less specialized morphology toward a fibrous and durophagous diet compared to the giant panda. These results are confirmed by a comparative analysis of the dimensions of the upper teeth in bears, which has revealed differences in relative tooth size between A. microta and A. melanoleuca, mostprobablyasa result of mosaic evolution. Therefore, we conclude that cranial shape did not remain essentially uniform in the Ailuropoda lineage, as previously thought, but underwent a number of changes during more than 2 Myr. © Springer-Verlag 2010.


Garcia-Aguilar J.M.,Campus Universitario Of Teatinos | Guerra-Merchan A.,Campus Universitario Of Teatinos | Serrano F.,Campus Universitario Of Teatinos | Palmqvist P.,Campus Universitario Of Teatinos | And 2 more authors.
Quaternary Science Reviews | Year: 2014

The continental sedimentary record of the Baza Basin (Guadix-Baza Depression, Betic Cordillera, SE Spain) shows six sedimentary units of lacustrine origin deposited from the latest Miocene to the Middle Pleistocene. Depending on the interval considered, the lacustrine deposits are mainly composed of marls, carbonates or gypsiferous evaporites, showing lithological, mineralogical and geochemical features (i.e., magnesium, strontium and sulfur contents, celestine deposits and travertine growths) that are evidence of intense, tectonically-induced hydrothermal activity. According to the high concentrations of strontium and sulfur as well as the abundance of travertines and magnesium clays, the supply of hot waters was greater during the Zanclean, the Gelasian and the Calabrian, as a result of tectonic activity. Hydrothermal activity has continued until the present time and is responsible of the hot springs that are nowadays active in the Guadix-Baza Depression. The paleoenvironmental consequences of these sublacustrine hot springs were that during some intervals the lakes maintained a relatively permanent water table, not subject to periodic desiccations in the dry season, and warmer temperatures throughout the year. This resulted in a high level of organic productivity, especially for the Calabrian, which allowed the development of a rich and well diversified mammalian community, similar to those of modern African savannas with tree patches. In this mild environment, the permanent water sheet favored the presence of drought intolerant megaherbivores such as the giant extinct hippo Hippopotamus antiquus. The high standing crop biomass of ungulates resulted in the availability of abundant carcasses for scavengers such as hyenas and hominins, which explains the very high densities of skeletal remains preserved in the sediments distributed along the lake surroundings. © 2013 Elsevier Ltd.


Ros-Montoya S.,Museo de Prehistoria y Paleontologia Municipal de Orce | Madurell-Malapeira J.,Autonomous University of Barcelona | Martinez-Navarro B.,Rovira i Virgili University | Espigares M.-P.,Museo de Prehistoria y Paleontologia Municipal de Orce | Palmqvist P.,Campus Universitario Of Teatinos
Quaternary International | Year: 2012

The late Early Pleistocene (Late Villafranchian) paleontological sites of Incarcal-I (Crespià, Catalonia, Spain) and Venta Micena (Orce, Andalusia, Spain), which are approximately 800 km apart, preserve a rich fossil record of proboscideans, corresponding to the species Mammuthus meridionalis. The remains from Incarcal-I have been described as an evolved form of the species. However, their comparison with the mandible of the same species from Venta Micena (with an approximate age of 1.4-1.6 Ma) and other specimens from different sites in Europe and Asia shows that the fossils from Incarcal-I and Venta Micena are very similar in morphology and metric data. Research suggests that the Catalonian specimens correspond to a form of the former species, which according to their morphology probably have a chronology closer to that of the Venta Micena specimens. © 2012 Elsevier Ltd and INQUA.


Figueirido B.,Campus Universitario Of Teatinos | Figueirido B.,Brown University | Serrano-Alarcon F.J.,Campus Universitario Of Teatinos | Palmqvist P.,Campus Universitario Of Teatinos
Journal of Zoology | Year: 2012

A morphometric analysis of the skull of the red or lesser panda, Aiulurus fulgens (Ailuridae), and the giant panda, Ailuropoda melanoleuca (Ursidae), was performed for evaluating the importance of natural selection and phylogenetic constraints in shaping the convergent morphological adaptations of these peculiar carnivores for feeding on bamboo. Principal components and discriminant analyses of landmark data was used in a comparative study across the families Procyonidae, Ursidae and Ailuridae. Skull morphospaces show that major patterns of morphological variation among these arctoid carnivorans correlate with differences in their feeding behavior. More specifically, this study has shown an extreme convergence in skull shape between the two bamboo specialists. Following the most recent molecular and morphological phylogenies, as well as the poor evidence from the fossil record, it seems highly improbable that homology could explain the shared morphology of the giant and red pandas, which lineages diverged ~40 million years ago. On the contrary, most phylogenetic and paleontological data suggest that convergent or parallel evolution (homoplasy) would be the evolutionary process shaping the common morphological traits of these unusual carnivorans. Therefore, the overall resemblance in skull shape between the giant and red pandas was probably driven by extrinsic factors (natural selection and adaptation for feeding on bamboo) as well as by intrinsic ones (the shared developmental pathway of the carnivoran skull, which posed some biomechanical constraints on the direction of the evolution of pandas). © 2011 The Authors. Journal of Zoology © 2011 The Zoological Society of London.


Korbee N.,Campus Universitario Of Teatinos | Teresa Mata M.,Campus Universitario Of Teatinos | Figueroa F.L.,Campus Universitario Of Teatinos
Limnology and Oceanography | Year: 2010

The photoprotective and acclimation capacity against ultraviolet radiation (UVR) was assessed for the dinoflagellate Heterocapsa sp. We examined the effect of UVR and N availability on photosynthetic activity and on the accumulation of photoprotective substances such as mycosporine-like amino acids (MAAs) and xanthophyll cycle pigments. Cells were cultivated under two different light treatments, photosynthetically active radiation (PAR) and PAR + UVR, and at two NaNO3 concentrations, mid nitrogen (MN, 0.1 mmol L-1) and high nitrogen (HN, 1 mmol L-1) for 6 d. MAA and photosynthetic pigment contents as well as maximum quantum yield of fluorescence (Fv : Fm) and electron transport rate were analyzed at the initial time and after 3 and 6 d of experimentation. Fv : Fm, decreased because of UVR and N limitation. N enrichment reduced the deleterious effect of UVR on photosynthesis. The content of photosynthetic pigments and MAAs was higher at HN than at MN supply and a positive effect of UVR on MAA and pigment accumulation was observed, suggesting that under HN conditions the deleterious UVR effect is counteracted by MAAs. Under N limitation thermal energy dissipation takes place by the xanthophyll cycle, i.e., an increase of the de-epoxidation degree was observed under these culture conditions. However, UVR seems to favor diadinoxanthin accumulation; thus, no photoprotection through the xanthophyll cycle seems available in cells exposed to PAR + UVR and MN. We conclude that not only MAA accumulation but also N availability is very important to determine the photoprotective capacity against UVR of Heterocapsa sp. © 2010, by the American Society of Limnology and Oceanography, Inc.


Castro-Rodriguez V.,Campus Universitario Of Teatinos | Garcia-Gutierrez A.,Campus Universitario Of Teatinos | Canas R.A.,Campus Universitario Of Teatinos | Pascual M.B.,Campus Universitario Of Teatinos | And 2 more authors.
BMC Plant Biology | Year: 2015

Background: Glutamine synthetase (GS; EC: 6.3.1.2, L-glutamate: ammonia ligase ADP-forming) is a key enzyme in ammonium assimilation and metabolism in higher plants. In poplar, the GS family is organized in 4 groups of duplicated genes, 3 of which code for cytosolic GS isoforms (GS1.1, GS1.2 and GS1.3) and one group that codes for the choroplastic GS isoform (GS2). Our previous work suggested that GS duplicates may have been retained to increase the amount of enzyme in a particular cell type. Results: The current study was conducted to test this hypothesis by developing a more comprehensive understanding of the molecular and biochemical characteristics of the poplar GS isoenzymes and by determinating their kinetic parameters. To obtain further insights into the function of the poplar GS genes, hybridization and laser capture microdissections were conducted in different tissues, and the precise GS gene spatial expression patterns were determined in specific cell/tissue types of the leaves, stems and roots. The molecular and functional analysis of the poplar GS family and the precise localization of the corresponding mRNA in different cell types strongly suggest that the GS isoforms play non-redundant roles in poplar tree biology. Furthermore, our results support the proposal that a function of the duplicated genes in specific cell/tissue types is to increase the abundance of the enzymes. Conclusion: Taken together, our results reveal that there is no redundancy in the poplar GS family at the whole plant level but it exists in specific cell types where the two duplicated genes are expressed and their gene expression products have similar metabolic roles. Gene redundancy may contribute to the homeostasis of nitrogen metabolism in functions associated with changes in environmental conditions and developmental stages. © Castro-Rodriguez et al.; licensee BioMed Central.


Canales J.,Campus Universitario Of Teatinos | Flores-Monterrosso A.,Campus Universitario Of Teatinos | Rueda-Lopez M.,Campus Universitario Of Teatinos | Avila C.,Campus Universitario Of Teatinos | Canovas F.M.,Campus Universitario Of Teatinos
Amino Acids | Year: 2010

Conifers have a preference for ammonium over nitrate as the main inorganic nitrogen source. However, it is unknown how changes in nitrogen nutrition may affect transcription profiles. In this study, microarray analysis and suppressive subtraction hybridization were used to identify differentially expressed genes in the roots of maritime pine exposed to changes in ammonium availability. A total of 225 unigenes that were differentially regulated by changes in ammonium nutrition were identified. Most of the unigenes were classified into seven functional categories by comparison with sequences deposited in the databases. A significant proportion of these genes were encoded for ammonium-regulated proteins of unknown functions. The differential expression of selected candidate genes was further validated in plants subjected to ammonium excess/ deficiency. The transcript levels of representative genes were compared in maritime pine roots, 1, 15 and 35 days after nutritional treatments. Gene expression patterns suggest the existence of potential links between ammoniumresponsive genes and genes involved in amino acid metabolism, particularly in asparagine biosynthesis and utilization. Functional analyses and exploration of the natural variability in maritime pine populations for a number of relevant genes are underway. © Springer-Verlag 2010.


Garcia-Aguilar J.M.,Campus Universitario Of Teatinos | Palmqvist P.,Campus Universitario Of Teatinos
Quaternary International | Year: 2011

The Early Pleistocene deposits of Guadix-Baza basin represent a depositional unit with distinctive features in the tectosedimentary history of this intramontane basin, which sedimentary infillings range in age between the uppermost Miocene and 45 ka. This Pleistocene unit has an average thickness of 10 m and is composed of carbonate lacustrine facies arranged in an upward-shallowing sequence. The paleontological richness of this unit is evidenced by its special sedimentological and paleoecological features. Diverse numerical analytic data related with the evolution of the sedimentary sequences and the establishment of the sedimentary and paleoecological scenario are presented. © 2011 Elsevier Ltd and INQUA.

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