Protocol for the reconstruction of micromammals from fossils. Two case studies: The skulls of Beremendia fissidens and Dolinasorex glyphodon

We have developed a protocol for reconstructing 3D models of the skulls of extinct species of small mammals. For the first time, the reconstruction uses fragments of fossils from a mixture of different specimens and from related extant species. We use free software and commercial computers to make the process reproducible and usable for the scientific community. We present a semi-quantitative protocol to face the problem of making 3D reconstructions of fossil species that are incomplete in the fossil record and/or represented by a mixture of different individuals, as usually occurs with small vertebrates. Therefore this approach is useful when no complete skull is available. The protocol combines the use of microCT scan technology with a subsequent computer treatment using different software tools for 3D reconstruction from microCT and 3D design and printing (e.g. Fiji, SPIERS, Meshlab, Meshmixer) in a defined order. This kind of free and relatively simple software, plus the detailed description, makes this protocol practicable for researchers who do not necessarily have great deal of experience in working with 3D. As an example, we have performed virtual reconstructions of the skulls of two species of insectivore small mammals (Eulipotyphla): Beremendia fissidens and Dolinasorex glyphodon. The resulting skulls, plus models of the extant shrews Blarina brevicauda, Neomys fodiens, Crocidura russula and Sorex coronatus, make it possible to compare characteristics that can only be observed by means of microCT 3D reconstructions, and given the characteristics of the material, using this protocol. Among the characters we can compare are the position of the mandibles, the spatial relations among all the teeth, the shape of the snout and, in general, all parameters related with the anatomy of the rostrum. Moreover, these reconstructions can be used in different types of context: for anatomical purposes, especially to see internal features or characteristics at whole-skull scale, for bioengineering, animation, or other techniques that need a digital model

A cave occupied by cave bears for thousands of years in the Sobrarbe-Pirineos UNESCO Global Geopark (Huesca, Aragon, Spain)

The Sobrarbe-Pirineos UNESCO Global Geopark shows an extremely well-developed underground karst relief as a result of the great abundance and thickness of its limestone formations. The most important Pleistocene vertebrate site within the Geopark is Coro Tracito Cave at Tella. The fossil association is made up exclusively of bones belonging to Ursus spelaeus from the upper Pleistocene, accumulated over several thousand years. Based on scientific analysis of the fossil bones, an interesting public outreach project has been organized, involving the refurbishment of the site within the cave and the creation of a permanent exhibition called the Tella Cave Bear Museum. These two infrastructures are visited by thousands of tourists each year and constitute the main geoscientific tourist attraction of the Sobrarbe-Pirineos Geopark

Birds from sima del elefante, atapuerca, spain: Palaeoecological implications in the oldest human bearing levels of the iberian peninsula

Palaeoenvironmental reconstruction of Early Pleistocene sites has a particular interest as it sheds light on how the arriving of the first Europeans occurred, as well as on the nature of the relation between these humans and the ecosystems. Bird remains are useful tools for this purpose, because they are commonly represented in the assemblages and most taxa still exist, allowing a direct comparison between past and extant birds associations. Here we analyse the bird remains from the Early Pleistocene levels of the Sima del Elefante site (1.1 to 1.5 million years old). Almost 10.000 remains belonging to at least 26 different taxa have been included. The assemblage is dominated by corvids and has a mixed origin, with cave-dwelling taxa dying in the cave and other taxa being accumulated by predators. The Sima del Elefante avian assemblage provides the oldest record of several taxa in the Iberian Peninsula (Haliaeetus albicilla, Corvus pliocaenus). Besides, here we report the oldest evidence of Imperial Eagle in the Iberian Peninsula, prior to the separation of the oriental and Iberian populations. The assemblage composition suggests that open environmental conditions were dominant, with minor presence of woodlands and water bodies, which is congruent with some previous approaches by other proxies. The first humans occupying the Iberian Peninsula inhabited under Mediterranean climate conditions, which gradually deteriorated, as reflected by the avian turnover recorded at the middle Pleistocene Atapuerca assemblages. © 2021 Universita degli Studi di Milano. All rights reserved

Bone accumulation by leopards in the Late Pleistocene in the Moncayo Massif (Zaragoza, NE Spain)

Eating habits of Panthera pardus are well known. When there are caves in its territory, prey accumulates inside them. This helps to prevent its kill from being stolen by other predators like hyenas. Although the leopard is an accumulator of bones in caves, few studies have been conducted on existing lairs. There are, however, examples of fossil vertebrate sites whose main collecting agent is the leopard. During the Late Pleistocene, the leopard was a common carnivore in European faunal associations. Here we present a new locality of Quaternary mammals with a scarce human presence, the cave of Los Rincones (province of Zaragoza, Spain); we show the leopard to be the main accumulator of the bones in the cave, while there are no interactions between humans and leopards. For this purpose, a taphonomic analysis is performed on different bone-layers of the cave

The fossils of Castor fiber from the middle pleistocene site of Gruta da Aroeira (Portugal) and human-beaver interaction

[eng[ Here we analyze the fossil remains of Castor fiber from the Middle Pleistocene site of Gruta da Aroeira, in the Almonda karst system, Tagus basin (Torres Novas, Portugal) and discuss the archaeological implications of the presence of beavers in the region. The Almonda karst system has been the backdrop for human evolution in Portugal, because there are different localities, of different ages, from the Middle Pleistocene to the Holocene, with fossil remains of hominins as well as faunal and archaeological remains. Beaver fossils have been found in the archaeological deposits of at least three cavities of the karst system: the Gruta da Aroeira, the Gruta da Oliveira and the Galeria da Cisterna. Here, for the first time, we describe the fossils of Castor fiber from Gruta da Aroeira. The beavers from Aroeira are remarkable because they are the westernmost fossil record of Castor fiber in Europe dated to Marine Isotope Stage (MIS) 11, around 420 ka. The aim of the present article is twofold, firstly to study the fossils of beavers from the Aroeira locality, and secondly to discuss the palaeoecological and palaeoenvironmental implications of the presence of this rodent in the Almonda karst sites. This allows us to discuss the hominin-beaver interactions.[fra] Ici, nous analysons les fossiles de Castor fiber du site Pléistocène moyen de Gruta da Aroeira, dans le système karstique de Almonda, bassin du Tage (Torres Novas, Portugal), et les implications archéologiques de la présence de castors dans la région. Le karst d'Almonda est un cadre de référence pour l’étude de l'évolution humaine dans la partie occidentale de l'Europe, du Pléistocène moyen à l'Holocène, avec aussi bien des restes d’hominidés fossiles, que de faunes et de vestiges archéologiques. Des fossiles de castors ont été trouvés dans les gisements archéologiques d'au moins trois cavités du système karstique : la Gruta da Aroeira, la da Oliveira et la Galeria da Cisterna. Ici, pour la première fois, nous décrivons les fossiles de Castor fiber de Gruta da Aroeira. Les castors d'Aroeira sont remarquables car ils sont la trace fossile la plus occidentale de Castor fiber en Europe; ils sont datés du Stade Isotopique Marin (MIS) 11, autour de 420 ka. Le but de cet article est double, d'une part de présenter l'évolution des castors à travers les fossiles d'Aroeira, et d'autre part de discuter des implications paléoécologiques et paléoenvironnementales de la présence de ce rongeur dans le karst d’Almonda. Cela nous permet de discuter des possibles interactions entre humains et castors

Implications of population changes among the Arvicolinae (Rodentia, Mammalia) in El Mirón Cave (Cantabria, Spain) for the climate of the last c. 50,000 years

The El Mirón Cave site in Spain has one of the most complete archaeological and palaeontological records of the Late Pleistocene in the Iberian Peninsula, encompassing most of the last c. 50,000 years. Among other studies, the fossiliferous record has allowed the development of various interpretations of faunal and climatic changes during this period of time in the northern Atlantic region of the Iberian Peninsula. The addition of more radiocarbon dates from El Mirón Cave make it possible to revise some of the interpretations of the micromammal sequence carried out earlier for this major site. The record of small mammals is one of the most used tools to study the climate of the past, and among them the several Arvicolinae species are of great importance for the study of Quaternary climatic variations, due to their adaptations to a great diversity of habitats. New methodologies such as ancient DNA and geometric morphometric analyses now permit us to conduct a review of the Arvicolinae species previously described at this site and better to differentiate between species with similar morphologies, like Microtus arvalis and M. agrestis. We also identified the presence of a species not recorded before in El Mirón, Terricola pyrenaicus. With the study of the Arvicolinae species associations, we reaffirm the climate variations originally described in this deposit, indicating in detail how the successive changes in temperature and environment took place throughout the course of the late Last Glacial and early Postglacial periods (Marine Isotope Stages 3–1)

The end of the Last Glacial Maximum in the Iberian Peninsula characterized by the small-mammal assemblages

This paper presents a palaeoenvironmental and palaeoclimatic approach to the end of the Last Glacial Maximum (LGM) in the Iberian Peninsula on the basis of the small-mammal assemblages (insectivores, bats and rodents). The LGM is an important period in our climate history defined by the maximum extension of ice sheets between ca. 22 and 19 ka BP. In the Mediterranean region the LGM is characte­rized by humid conditions, which allow for the development of arboreal vegetation. The small-mammal remains described in this study were recovered from four different sites within the Iberian Peninsula: El Mirón cave (Ramales de la Victoria, Cantabria), Valdavara-1 (Becerreá, Lugo), El Portalón (Sierra de Atapuerca, Burgos), and Sala de las Chimeneas (Maltravieso, Cáceres). We found in these sites a non-analogue association represented by species associated with mid-European climatic conditions, such as the voles Chionomys nivalis, Microtus arvalis, Microtus agrestis and Microtus oeconomus, together with species associated with Mediterranean requirements, such as Microtus (Iberomys) cabrerae and Microtus (Terricola) duodecimcostatus. These assemblages reveal that the climate was harsher than today in the sites under study, though not as rigorous as elsewhere in Europe, with mean annual temperatures lower than present and an environment dominated by wet open meadows. All our data have been compared with other environmental and climatic proxies, global isotope curves and pollen data, providing a scenario for the palaeoclimatic and palaeoenvironmental conditions that occurred during the LGM in the Iberian Peninsula.Este artículo representa un enfoque paleoambiental y paleoclimático del final del Último Máximo Glacial (UMG), en la Península Ibérica a partir de las asociaciones de pequeños mamíferos (insectívoros, murciélagos y roedores). El UMG es un período importante en nuestra historia del clima definido por la máxima extensión de las capas de hielo entre ca. 22 y 19 ka BP. En la región del Mediterráneo, este UMG se caracteriza por condiciones de humedad, que permiten el desarrollo de la vegetación arbórea. Los restos de micromamíferos seleccio­nados para este estudio corresponden a cuatro yacimientos diferentes de la Península Ibérica: la cueva del Mirón (Ramales de la Victoria, Cantabria), Valdavara-1 (Becerreá, Lugo), El Portalón (Sierra de Atapuerca, Burgos), y la Sala de las Chimeneas (Maltravieso, Cáceres). En todos los yacimientos estudiados se ha encontrado una asociación representada por las especies relacionadas con las condiciones cli­máticas medio-europeas, como los topillos Chionomys nivalis, Microtus arvalis, Microtus agrestis o Microtus oeconomus, junto con las especies asociadas con los requerimientos mediterráneos, como Microtus (Iberomys) cabrerae o Microtus (terricola) duodecimcostatus. Estas asociaciones nos permiten observar que el clima era más frío que hoy en día en los diferentes yacimientos estudiados, pero no tan riguroso como en otros lugares de Europa, con temperaturas medias anuales más bajas que en la actualidad y un entorno dominado por pra­dos húmedos. Los resultados de este estudio han sido comparados con otros datos ambientales y climáticos, las curvas climáticas globales de isótopos y datos polínicos, proporcionando un escenario para las condiciones paleoclimáticas y paleoambientales que ocurrieron durante el UMG en la Península Ibérica

Los Batanes (Biescas, Spain), a roost site for horseshoe bats in the Pyrenees during the late Pleistocene

Los Batanes C4 is a cave-site in the Spanish Pyrenees, the minimum sediment calendar age was determined to be 15, 234 ± 223 cal BP by radiocarbon dating. The cave opens on the northern bank of an eastern tributary of the River Gállego, at an altitude of 1025 m. The small vertebrates recorded are mainly bats, in order of abundance Rhinolophus euryale, R. ferrumequinum, Myotis sp. and Miniopterus schreibersii. The association suggests that at the time of the accumulation the climate was reasonably similar to the current climate; we situate it within a period of local retreat of the ice-cover in the Gállego Valley during the Lateglacial. This is the highest record of these species of Rhinolophus in the Iberian Quaternary, showing that the R. euryale altitudinal range was similar to its extant range during the favourable periods of the Lateglacial. This could indicate that this taxon was relatively quick in spreading into higher regions whenever climate conditions allowed it

Small mammals from the middle pleistocene layers of the sima del elefante (Sierra de Atapuerca, Burgos, northwestern Spain)

The Sima del Elefante site, located in the Sierra de Atapuerca (Burgos, Spain), is an important Pleistocene archaeopalaeontological locality that has been excavated every year since 1996. At least two main infill phases have been identified: a first (TELRU) early Pleistocene phase that has provided a rich faunal assemblage, various stone tools and the earliest human remains from western Europe; and a second phase (TEURU) attributed to the Middle Pleistocene. In this paper, for the first time we present a description of the TEURU small-mammal assemblage and its subsequent biochronological, palaeoenvironmental and palaeoclimatic implications. The small-mammal assemblage is highly diverse and comprises at least 17 species: 3 insectivores (cf. Erinaceus sp., Crocidura sp. and Sorex sp.); 4 chiropters (Rhinolophus ferrumequinum, Rhinolophus gr. euryale-mehelyi, Myotis gr. Myotisoxygnathus and Miniopteurs schreibersii); 9 rodents (Myodes glareolus, Microtus arvalis, Microtus agrestis, Iberomys brecciensis, Terricola cf. atapuerquensis, Arvicola sp., Apodemus sylvaticus, Eliomys quercinus and Allocricetus bursae) and 1 lagomorph (Oryctolagus sp.). Such an association suggests a late Middle Pleistocene age (ca. 250-350 ka), a patchy landscape dominated by humid meadows and woodland areas, and mild climatic conditions. These results are compared with other proxies, such as the herpetofauna, malacofauna, large-mammals and charcoals, providing a new scenario for the climatic and environmental conditions that prevailed during the latest Middle Pleistocene in the Sierra de Atapuerca

Pleistocene cave hyenas in the Iberian Peninsula: New insights from los aprendices cave (Moncayo, Zaragoza)

A new Pleistocene paleontological site, Los Aprendices, located in the northwest-ern part of the Iberian Peninsula in the area of the Moncayo (Zaragoza) is presented. The layer with fossil remains has been dated by amino acid racemization to 143.8 ± 38.9 ka (earliest Late Pleistocene or latest Middle Pleistocene). Five mammal species have been identified in the assemblage: Crocuta spelaea (Goldfuss, 1823) Capra pyre-naica (Schinz, 1838), Lagomorpha indet, Arvicolidae indet and Galemys pyrenaicus (Geoffroy, 1811). The remains of C. spelaea represent a mostly complete skeleton in anatomical semi-connection. The hyena specimen represents the most complete skel-eton ever recovered in Iberia and one of the most complete remains in Europe. It has been compared anatomically and biometrically with both European cave hyenas and extant spotted hyenas. In addition, a taphonomic study has been carried out in order to understand the origin and preservation of these exceptional remains. The results sug-gest rapid burial with few scavenging modifications putatively produced by a medium sized carnivore. A review of the Pleistocene Iberian record of Crocuta spp. has been carried out, enabling us to establish one of the earliest records of C. spelaea in the recently discovered Los Aprendices cave, and also showing that the most extensive geographical distribution of this species occurred during the Late Pleistocene (MIS4-2)