Caracterización ecomorfológica del esqueleto postcraneal en rumiantes (Artiodactyla, Mammalia): aplicación en la inferencia de las adaptaciones ecológicas de los rumiantes del plio-pleistoceno de España

Recent and extinct ruminants have diversified into numerous niches over time. Their functional morphology has been widely used in paleoenvironmental reconstructions, since its members have been considered sensitive indicators of climate and landscapes changes. Most studies have focused on dentition and cranial features, pushing the postcranial skeleton into the background. However, skeletal structure provides extremely useful information about locomotor system, which can likewise offer clues about environment. In other words, locomotor adaptations seem to be related to specific patterns of predator avoidance and food search strategies that are habitat specific. To expand the knowledge that we have so far about such relations, and subsequently, to infer them in fossils, the present work examines in detail the autopod of a number of extant and Plio-Pleistocene ruminants from three Mediterranean localities (Villarroya, La Puebla de Valverde and Saint-Vallier). The number of morphological characters considered by other authors to date has been enlarged and enhanced, as well as the habitat range. Phylogeny has also been taken into account in a first approach. Results show that two main groups may be established based on locomotion: gallop-stotting (type I) and bounding gallop-zigzagging (type II). The first is mainly used by species living in open and clear environments, which principally are bovids (except Cephalophines). The latter is primarily practiced by moschids, tragulids and cephalophines living in dense habitats. Another important conclusion to be drawn is that metatarsal III-IV can be considered the best ecological indicator among autopod bones, while the rest of the elements provide more limited information. It can be summarized that those bones with strong insertion marks and traits limiting the movement in a parasagittal plane, belong to species with type I locomotion. In contrast, weaker marks and morphologies allowing lateromedial swings are characteristic for those species with type II locomotion. These ecomorphological characters, defined by extant taxa morphology, have been applied to fossil species, finding that both Metacervoceros rhenanus as Eucladoceros senezensis lived in forests with well-developed understories and close to wetlands. In contrast, Gazella borbonica and Gazellospira torticornis inhabited more arid, open and clear environments, probably with abundant sandy and/or stony substrates. The ecotonal habitat between these two landscapes would be occupied by Croizetoceros ramosus and Leptobos elatus, which seem to have more ubiquitous lifestyles. Croizetoceros prefered denser areas, while Leptobos inhabited more open spaces. The caprines, Hesperidoceras merlae and Gallogoral meneghinii, probably occupied steep terrains and adjacent plains in the vicinity of the fossil sites. The less rough zones of these areas could have been inhabited, at least seasonally, by Gazella and Gazellospira. In this work, we have also relied on analogies with extant communities, developing a new paleoecological method to infer bioclimatic conditions from the locomotor spectrum of fossil communities. Bioclimatic analyses show that it is possible to discriminate tropical/subtropical vs. temperate, arid vs. humid, and forest vs. non forest biomes (with 70%, 68% and 70% of correct classification respectively). Based on all this information, we propose a mosaic environment for the fossil localities, with a predominance of arid plains, but dotted with forest patches and steep landscapes. Bioclimatic analyses provide temperate and non forest regional conditions for the three localities. However, regional climate would be more arid in Villarroya and Saint-Vallier than in La Puebla de Valverde

The contribution of phylogenetics to the study of ruminant evolutionary ecology

The increasing availability of published evolutionary trees and phylogenetic methods has changed the way we tackle the study of evolution. In this sense, ruminants have become one paradigmatic object of study due to their ecological variety and well-known evolutionary history. The last decades of ruminant research have benefited from diverse phylogenetic approaches, offering new perspectives on classic ideas and, sometimes, allowing to test previously untestable hypotheses. As a result, we now start to understand the complexity of the evolutionary responses of this clade to past global environmental changes. This is a brief review of some of the most outstanding and groundbreaking tree-based contributions to the research on the evolutionary ecology of this fascinating group of herbivorous macromammals.Peer reviewe

Above the hoof: functional morphology of the fossil deer from Tegelen, the Netherlands

Villafranchian faunas were widely spread throughout the European continent during the Plio-Pleistocene. Ungulates, and particularly ruminants, are very well represented in most of the localities of this period. The fossil site of Tegelen (Province of Limburg, the Netherlands) is a classical Villafranchian locality where cervids are especially abundant. Some of the sites from this period have been thoroughly studied in various aspects, such as faunal assemblages, biochronology, magnetostratigraphy, sedimentology or palaeoenvironmental conditions, among others. Tegelen has been as well studied, but its particular exploitation has hampered its study for years. In order to reconstruct its prevailing palaeohabitat, we have applied statistical analyses based on functional morphology for the first time for this fossil site. In this work, we have analysed the ecomorphology of the postcranial skeleton of Eucladoceros ctenoides and Metacervoceros rhenanus, the two extinct species of deer present in Tegelen. Results show that the best ecological indicators are the metapods and the tibia, while the astragalus seems to be the least informative element. The analyses reveal likewise how both taxa show adaptations to both open and forest environments, but with a slight trend to the former. These results disagree with the general assumption that E. ctenoides and M. rhenanus are indicative of forested settings, as well as with the classical interpretations of the palaeoenvironment of Tegelen made to date, which are exclusively based on the fauna. However, they go along with the appearance of some taxa typical of open habitats, such as the micromammals Hystrix and Dicrostonyx, which could help to explain their enigmatic presence.Peer reviewe

Análisis de los patrones de coloración en bóvidos (Ruminantia, Artiodactyla): aplicaciones en la paleorreconstrucción de Tethytragus Azanza & Morales, 1994

This work offers a tentative interpretation of the possible coat colour pattern of the Miocene bovid genus Tethytragus. The method used includes a maximum likelihood reconstruction analysis of data collected from all the 55 species of extant ruminants pertaining to the monophyletic group including the subfamilies Aepycerotinae, Alcelaphinae, Hippotraginae, Pantholopinae y Caprinae. We inferred three different options of colour patterns, corresponding to the basal nodes of the phylogeny of such a group. All of these options share a series of common characteristics: neutral coloured body, white rump patches and possibly darker limbs and tail, as well as a white belly. The only apparent facial marks are hite lips and possibly a dark nasal region

Dental microwear analysis in Gliridae (Rodentia): methodological issues and paleodiet inferences based on Armantomys from the Madrid Basin (Spain)

In the present study we analyze the microwear of the species included in the lineage Armantomys aragonensis-A. tricristatus of two samples from two middle Miocene localities from the Madrid Basin (El Cañaveral and Casa Montero). The methodological part of the study compares light stereomicroscope photographs from resin casts and Environmental Scanning Electron Microscope (ESEM) photographs from original material. Furthermore two regions of the tooth crown (the most lingual part of the anteroloph, and the most lingual part of the protoloph) and two homologous regions of first and second upper molars have been analyzed. The paleoecological part includes the results of the microwear analyses of the two species included in the lineage A. aragonensis-A. tricristatus. The replacement of A. aragonensis with A. tricristatus in the Madrid Basin occurred during the Middle Miocene Climate Transition (MMCT) and is marked by a change in dental morphology. Therefore, in order to infer changes in diet associated to a shift in the environment, we checked for correlations on microwear features between the two different morphologies of the species. The two methodologies tested, ESEM on original teeth and light stereomicroscopy on resin casts, showed similar results on microwear analysis in the glirid Armantomys. Besides, both regions of the tooth crown and dental elements showed the same microwear patterns. The substitution of the species included in the lineage Armantomys aragonensis-A. tricristatus might not imply a change in diet

Taphonomy of mammalian fossil bones from the debris-flow deposits of Somosaguas-North (Middle Miocene, Madrid Basin, Spain)

Debris-flow hosted assemblages dominated by mammalian remains are very scarce in the fossil record and few examples are reported. Herein we present a detailed taphonomic study of Somosaguas-North (Madrid Basin,Spain), a Middle Miocene mammalian-dominatedsite embedded in debris-flow deposits, in order to increase our knowledge of the mode of formation of fossiliferous assemblages in this depositional context. The assemblage includes 6592 large-mammal remains belonging to at least 10 different species. Fossils are found in matrix-supported, poorly-sorted coarse arkosic sandstones and fine conglomerates, which are interpreted as the result of successive debris-flow deposits. Breakage constitutes a pervasive taphonomic alteration in the bone assemblage; however, together with unidentifiable bone fragments, we also found complete to almost complete skeletal elements Bone remains are isolated, a fact that is indicative of a time of exposure of the carcasses long enough to enable decay and complete disarticulation. There are no associations of elements belonging to the same individual, which suggests that, prior to or during debris-flow transport, bones were profusely dispersed. Based on the taphonomic evidence, we suggest that Somosaguas-North assemblage was formed by successive debris-flow transport and burial of pre-existing thanatocoenoses. Bones from those thanatocoenoses were modified by biostratinomic agents (trampling, weathering) in varying degrees depending on their time of exposure. Debris-flow transport produced further abrasion and breakage in collagen-depleted bones. Our results are congruent with an environmental context of semiarid landscapes presenting long arid periods and highly irregular hydrological seasonality. Finally, we compared the Somosaguas-North assemblage with other debris-flow hosted vertebrate assemblages. Although Somosaguas-North shares taphonomic features with some of these sites, it is not possible to define consistent and singletaphonomic patterns for debris-flow assemblages, given the varied taphonomic histories of the remains prior to and during debris-flow transport

Neogene Mammal Sites in Molina de Aragón (Guadalajara, Spain): Correlation to Other Karstic Sites of the Iberian Chain, and their Geoheritage Values

Corral de Lobato, a karstic site in the area of Molina de Aragón has been studied in a preliminary way. Even though there are not many Neogene karstic sites in the Iberian Chain, they occur in four clusters, with ages ranging from latest middle Miocene (MN7/8) to early Pleistocene (MN17). Correlations between these clusters and the reference stratigraphical units of the Tagus Basin, as well as with local and global events, are proposed. These karstic sites provide a complementary source of fossil vertebrate remains to that of the stratified sites formed lowland. The Heritage significance of such sites arises from the enhanced preservation of rare taxa or associations, and the operation of biotic concentrative processes.This work received financial support from the research projects CGL2015–68333-P (MINECO/FEDER, UE), Research Group BSCH-UCM 910607 and Consolidated Research Group EO5 (Aragón Government).Peer reviewe

Palaeontological fossil sites as didactic resources in experimental sciences

Proyecto sobre el uso de yacimientos paleontológicos como recurso didáctico, en la docencia de la Ecología y el desarrollo sostenible, en Educación Infantil, Primaria, Secundaria y Bachillerato, con visitas virtuales a yacimientos paleontológicos.UCMDepto. de Didáctica de las Ciencias Experimentales , Sociales y MatemáticasFac. de EducaciónFALSEsubmitte

El sistema de yacimientos de mamíferos miocenos del Cerro de los Batallones, Cuenca de Madrid: estado actual y perspectivas

77 págs, 24 láms.The Cerro de los Batallones (Los Batallones Butte) is located in the central-northern area of the Madrid Basin, central Spain. Nine vertebrates localities containing a large variety of mammals of Upper Vallesian Age (Late Miocene) have been found associated with the sediments forming the butte. From bottom to top, these sediments consist of magnesian lutite beds (Unit I), paleosols formed of sepiolite and opal (Unit II), and siliclastic, marlstone and carbonate beds (Unit III). The set of ERT profiles developed in Los Batallones Butte have demonstrate that electrical imaging techniques are an estimable tool for the characterization and prospecting of fossil sites developed in fine-grained siliciclastic sequences. These localities contain an exceptionally rich, varied and well-preserved vertebrate fauna together with invertebrate and plant fossils. Carnivore species are strikingly well represented at Batallones 1 and 3, and large herbivore species, such as mastodons, rhinoceros and giraffes, at Batallones 2, 4, 5 and 10. The taphonomical studies, together with the morphological features shown by the sedimentary fills of the mammal localities, permit an overall interpretation of these deposits as vertebrate traps. The study of these localities should offer a significant contribution to our understanding of the formation pattern of trap-like paleontological sites - which so far have been typically reported in karstic-type systems -, as well as an important source of paleobiological information about numerous vertebrate groups.Nuestro sincero agradecimiento a la Comunidad de Madrid (Dirección General de Patrimonio Histórico Artístico) por su apoyo a lo largo de todos estos años. A la empresa TOLSA, SA por su inapreciable ayuda en todas las circunstancias. National Geographic Society financió la campaña de Batallones-1 del año 2001. Son muchos los compañeros y amigos que han participado en las excavaciones, y en los diferentes proyectos de investigación de estos yacimientos, a todos ellos nuestro más sincero agradecimiento y nuestros mejores deseos, con la esperanza de seguir contando con su valiosa colaboración. Este trabajo se ha realizado en el marco de los proyectos de investigación MEC 2005-03900/BTE y CGL2006-01773/BTE, y del Grupo de Investigación CAM-UCM 910607.Peer reviewe

Los yacimientos paleontológicos como recurso didáctico II: las visitas virtuales como recursos didácticos en las Ciencias de la Naturaleza.

Depto. de Didáctica de las Ciencias Experimentales , Sociales y MatemáticasFac. de EducaciónFALSEsubmitte