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We present an updated taxonomy and faunal distribution of the micromammal fossil record from the Aragonian and Lower Vallesian of the Calatayud-Montalbán Basin. The analysed record includes the orders Rodentia, Eulipotyphla, and Lagomorpha. The pattern of species turnover shows seven major faunal events, which are correlated with major climate changes based on marine stable oxygen and carbon isotope records. Episodes δ 18 O Mi-2 and Mi-3 are significantly correlated with major micromammal turnover at the boundaries between the Lower and Middle Aragonian and the Middle and Upper Aragonian, respectively. Our results support the existence of a selective turnover during the Aragonian and Lower Vallesian. [ABSTRACT FROM AUTHOR]

Abstract: A recently developed method in palaeoclimatology, bioclimatic analysis, which makes it possible to extract a maximum of information from the available mammal proxy-data, is applied to a succession of fossil rodent assemblages recorded from the Pliocene and Pleistocene in the Iberian Peninsula. It consists of both qualitative and quantitative models with the capacity to produce a detailed palaeoclimate reconstruction, which is consistent with palaeobotanical, and isotopic proxy-data and the physics of atmospheric models. Using this method, the palaeoclimate of the Iberian Plio-Pleistocene is reconstructed with high resolution from 44 fossil rodent assemblages, comprising more than a hundred identified species. Analysis of these assemblages shows that the climatic evolution of the Iberian Peninsula during the Plio-Pleistocene can be divided into four distinct climatic phases. First, a long phase of subtropical climate with summer rainfall and winter drought occurred during the Ruscinian. Second, between 3.4 and 2.5 my B.P., there was a cooling phase coincident with the development of the northern hemisphere ice-sheets. Following this cooling, a temperate interlude occurred between 2.5 and 1.8 my B.P. During this phase the Mediterranean climate was established permanently in southwestern Europe. Finally, during the Pleistocene, temperate and colder stages were succeeding in relationship with the northern hemisphere glaciations. This sequence of climatic changes is linked with the tectonic rising of the central Asian and east African plateaus, variations in the atmospheric circulation pattern and changes in the Mediterranean Sea surface temperatures. All these factors led to associated changes in the precipitation regime and a latitudinal displacement of the zonal climatic belts. [Copyright &y& Elsevier]

El Cerro de los Batallones is one of the most important fossil sites of the Miocene. The quantity and preservation of its fossil remains have allowed us to describe many new mammal species. One of these is Hispanomys moralesi, a derived species of the Tribe Cricetodontini, a wide group of rodents with great importance in the faunal assemblage during the Miocene. Unlike most fossil micromammals in this fossil site, we have obtained skull remains that preserve never recorded anatomical structures in this time interval. Due to the fragility of the material, it could only be studied in detail using X-ray micro-computed tomography (µ-CT Scan). With this technique, we obtained three-dimensional models of 12 skulls of Hispanomys moralesi, in which different osteological parts have been described. In this way, we compared the morphological variation of the skull with other fossil cricetids and concluded that Batallones' species is an opisthodont rodent, with a relatively elongated rostrum, a robust base of zygomatic arches and big-sized tooth rows. Opisthodont incisor characterises omnivore and herbivore diets in rodents. Therefore, these new findings of Hispanomys moralesi could allow us to describe the dietary affinities of this extinct species. [ABSTRACT FROM AUTHOR]

The tribe Cricetodontini is a common cricetid group found in several European basins from the Miocene. Here we present a study of the fossils of this group found in the Duero Basin. We updated the biostratigraphical assignation of some of the localities in which several species of Cricetodontini have been found. Cricetodontini remains from eight localities from the central sector of the Duero Basin have been described, measured and assigned to a species. The presence in these localities ofHispanomys aguirrei,H. lavocati,H. nombrevillaeandH. aragonensishas allowed correlating them to the biostratigraphic scale built for the Miocene in Calatayud-Daroca Basin, identifying biozones G3, H and I (MN7/8 – MN10, Late Aragonian – Early Vallesian, Middle – Late Miocene). Furthermore, this study constitutes the first citation of this species in this basin, exceptH. aguirrei, previously described in the Duero Basin. After this work, the biostratigraphical assignation of the studied sites is now well known. We evidenced the resemblance of Duero and Calatayud-Daroca basins. [ABSTRACT FROM PUBLISHER]

Identifying the drivers of adaptation is key to understanding the origin and evolution of diversity. Here we study the morphological evolution of tooth morphology, a classic example of a conserved structure, to gain insights into the conditions that can overcome resistance to evolutionary change. We use geometric morphometrics of the occlusal surface outline of the fourth lower premolar (p4) of squirrels, a paradigm of a stable tooth morphology, to explore morphological adaptations to diet. Although a versatile generalist dental morphology favors the retention of the ancestral shape, the acquisition of diets that require strong mechanical processing drives morphological change. In particular, species that eat both grass and dry fruits evolved disparate tooth shape morphologies, related to trade-offs between feeding performance that lead to a more or less pronounced change depending on the proportion of those items in their diet. Also, some folivores develop relatively large p4s, and most bark gleaners have relatively small p4s. Ultimately, despite the role of diet shaping these patterns, we showed that diet is not the only factor driving the evolution of tooth morphology. [ABSTRACT FROM AUTHOR]

The most updated stratigraphical distributions of the Cricetodontini from the Calatayud–Daroca Basin are presented. Cricetodon sansaniensis (local biozone F, MN6, middle Aragonian) and Cricetodon jotae (local biozone G1, G2 and G3, MN6-MN7/8, Middle–Upper Aragonian) from the middle Miocene are described and discussed. Generally, the genera of Cricetodontini were used to define large time intervals, whereas the species were neglected in the local biostratigraphical studies. The results presented herein show that, for the Calatayud–Daroca Basin, most of the stratigraphical distributions of the species of Cricetodontini are strongly linked with the local biozonation. That reveals that they could be used as good biostratigraphical indicators. Moreover, the unusually long local biozone G3 could be redefined and subdivided based on the distributions of the four species of Cricetodontini present in it. However, it is recommended to complete the study of the whole rodent fauna before proposing a new biozonation. [ABSTRACT FROM AUTHOR]

Abstract: In order to develop paleoecological studies involving many fossil sites, there is a need to establish a consistent time framework, which enables us to arrange the fossil associations according to a sequence of biotic events and subsequently to test a relationship with paleoenvironmental changes. The nature of the continental fossil record has given rise to much controversy with regard to the establishment of general biostratigraphical scales. Additionally, biochronological scales are sometimes all that can be proposed. The primary goal of the present paper is to present a time arrangement for the Iberoccitanian micromammalian fossil sites from the latest Middle Miocene to the Mio–Pliocene boundary, spanning around 7millionyears (approximately 12.61–4.95Ma). Herein we study over one hundred faunal lists of rodents from the Iberoccitanian Region, compiled from the literature. Previous research has described two biogeographical provinces in our study area: a northern one (Vallès–Penedès and southeast France) and a southern one (all the Iberian basins, except the Vallès–Penedès). We therefore conducted Alroy''s Maximum Likelihood Appearance Event Ordination (ML AEO) methodology, applying it to the database compiled for each province. Finally, using available numerical dates for a quarter of the sites, we obtained a calibrated ordination for all localities. In each analysis, the results obtained are roughly coherent with the Mammalian Neogene units (MN) and allow estimation of the numerical ages for the entire set of fossil sites included in the study. Nevertheless, our results show severe diachrony between the two biogeographic provinces of the Iberoccitanian Region in relation to the MN boundaries, which might be linked to the existence of a refuge area associated with more humid environments in the northern province. [Copyright &y& Elsevier]

The shape of the tree of life is the result of shifting diversification rates, and identifying the factors driving these shifts is one of the main aims in evolutionary biology. Various biotic and abiotic factors have been proposed to have an impact on mammal diversification, such as climatic and tectonic changes, the acquisition of new traits, and expansion into new ecosystems or landmasses.We used phylogenetic comparative methods to quantify the influence of potential drivers on diversification patterns in extant squirrels (Sciuridae, Rodentia). We conducted a multilayer approach, comparing diversification rates among squirrel lineages depending on their degree of biome specialisation, biogeographic realm occupancy, locomotion adaptations, and presence in mountainous regions.We generated the most complete phylogeny of squirrels to date, encompassing almost 80% of the extant species, and applied multiple and binary state‐dependent diversification models. All the traits examined showed an influence on diversification rates.The biome specialist lineages showed the highest speciation rates, suggesting a major role of bioclimatic specialisation on macroevolutionary patterns. A single major event, the Miocene–Pleistocene radiation of terrestrial‐adapted lineages in North America, left a signal that was recovered in two of our analyses. Both the Nearctic lineages and the terrestrial‐adapted lineages showed high speciation rates, highlighting the fact that that major evolutionary episodes may produce confounding effects in state‐dependent diversification models.Ancestral reconstructions showed that cold and warm intervals in Earth's history had different effects on squirrels' diversification, depending on their climatic affinities. Tropical and arboreal squirrels evolved predominantly in the warm intervals, while terrestrial and cold‐adapted squirrels radiated in the cold intervals.Our findings suggest that, while global climatic shifts are key for the speciation processes in mammalian lineages, lineage‐specific ecological adaptations are critical modulators of the responses of lineages to such environmental shifts, in an interplay that ultimately affects their diversification patterns. [ABSTRACT FROM AUTHOR]

We describe new dental remains of the genus Iberictis (Carnivora: Mustelidae) from the late early Miocene of the Iberian Peninsula. The new fossils of Iberictis azanzae from Artesilla (16.5–16.3 Ma, MN4; Calatayud-Teruel Basin, Zaragoza, Spain) add important morphological information about this species. Material from another species, Iberictis buloti, is described from els Casots (16.5–16.3 Ma, MN4; Vallès-Penedès Basin, Barcelona, Spain). This material constitutes the most complete sample of Iberictis and the first record of I. buloti in the Iberian Peninsula. Our analyses confirm the taxonomic validity of both species, and confirm the more plesiomorphic status of I. buloti compared to I. azanzae. Re-examination of large mustelid Miocene genera (Dehmictis, Ekorus, Eomellivora, Hoplictis, Iberictis, Ischyrictis, and Plesiogulo) and their inclusion for the first time in a cladistic analysis indicate that Iberictis is the sister taxon of Plesiogulo, and that these genera constitute the sister group of the extant wolverine (Gulo gulo). Our analysis thus confirms a close relationship between the early Miocene Iberictis, the late Miocene Plesiogulo, and the Plio-Pleistocene Gulo. Iberictis is the oldest member of Gulonini, the total clade of wolverines, thereby tracking the fossil record of this clade back to the early Miocene. We further propose a new systematic arrangement for the aforementioned large Miocene mustelids into the subfamilies Guloninae, Mellivorinae, and Mustelinae. [ABSTRACT FROM AUTHOR]

Abstract: Vallesian (early Late Miocene) strata from the recently introduced Cañada section (province of Zaragoza, east Central Spain) have yielded fairly large insectivore assemblages. These show that, after the generally dry Aragonian, the Vallesian gave rise to more humid conditions that were favourable to insectivores, both in number of taxa, and in overall number of specimens. The assemblage of Cañada 8 (Biozone H) is dominated by shrews, whereas the assemblage of Cañada 10 (uppermost Biozone H) contains the oldest record of Desmanella in the area. This seems to signify a bioevent in which after millions of years of absence, talpids return to the area. In addition to the Vallesian assemblages, a small Turolian insectivore fauna has been recovered. On the basis of the rodents, Cañada 12 was assigned to Biozone L, and the insectivore assemblage is very similar to the assemblages from the Teruel basin of that zone. This implies that the discovery of Postpalerinaceus in Cañada 12 is the youngest published record of this large spiny hedgehog. [Copyright &y& Elsevier]

We describe cranial, mandibular, and dental remains of five individuals of the giant mustelidEomellivora piveteauiOzansoy, 1965, from the late Miocene (MN10) site of Cerro de los Batallones (Madrid, Spain)—the first complete cranial remains recorded for this species and the most complete remains of the genus. This new sample enables a review of the systematic status ofEomellivora, leading us to accept as valid the speciesE. piveteauiOzansoy, 1965,E. wimaniZdansky, 1924,E. ursogulo(Orlov, 1948), andE. hungaricaKretzoi, 1942. Our phylogenetic hypothesis indicates thatEomellivorais the sister taxon of the extantMellivora capensisandE. piveteauihad a common ancestor within the crown groupE. wimani–E. ursogulo. Eomellivora piveteauiwas specialized for a more hypercarnivorous diet than the largest extant terrestrial mustelids, although it also had some derived bone-crushing adaptations.Eomellivora piveteauihad an active predatory role in the late Miocene carnivore faunas, exploiting both small and relatively large prey. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free atwww.tandfonline.com/UJVP [ABSTRACT FROM PUBLISHER]