This paper analyses the relationship between the evolution of the Late Miocene and Early Pliocene rodent and insectivore assemblages from the Granada Basin (southern Spain) and climate changes. These ...climatic changes, in terms of humidity and temperature fluctuations, are inferred from variations of the relative abundances of taxons with definite ecological preferences. There is a general tendency towards a temperature increase from the latest Tortonian (Middle Turolian) to the Messinian (Late Turolian), and towards a decrease from the Mio-Pliocene boundary (latest Turolian–earliest Ruscinian) to the end of the Zanclean (Late Ruscinian). Dry conditions predominate in the latest Tortonian (Middle Turolian). At the beginning of the Messinian (Late Turolian) there was a significant increase in humidity, followed by an aridification throughout the end of the Messinian and Zanclean (Late Turolian and Ruscinian). These climatic variations are in accordance with the sedimentary evolution of the basin, and agree with the climatic interpretations inferred from the shallow-marine carbonate sediments (temperate/ tropical) deposited in the marine basins of southeastern Spain during the studied time interval.
Aim: The Messinian salinity crisis (MSC) was an extraordinary geological event that affected the whole Mediterranean region as well as the global marine circulation between 5.97 and c. 5.33 Ma. One ...of its most direct effects was the emersion of land masses and the subsequent establishment of land bridges that led to common terrestrial faunal exchanges. However, the details of the onset of these exchanges have been a matter of controversy. New findings from southern Iberia of small mammal remains with African similarities have enabled us to review the Messinian faunal exchanges in the Mediterranean region. Location: Mediterranean region. Methods: Small mammal remains with African similarities from two new southern Iberian sites were studied. The small mammal associations of eight Miocene-Pliocene North African sites were also reviewed. Results: Two taxa with African similarities were identified at the Iberian study sites: Debruijnimys almenarensis and a Ruscinomys-like form (cf. Ruscinomys) with a strong spur in the lingual lobe of the anterocone in the M¹, a feature observed in North African Ruscinomys and eastern Mediterranean Byzantinia. The taxonomic status of some North African species and/or genera, such as Castillomys, Occitanomys and Prolagus, should be revised according to the new phylogenetic relationships established in European faunas. Main conclusions: Two hypotheses can be proposed for the origin of the African Ruscinomys: (1) among the Iberian Ruscinomys or (2) from the eastern Mediterranean Byzantinia. Our data, currently from only a few, albeit significant, taxa, tend to support an Iberian origin. The discussion presented in this paper suggests an age near the closure of the last Betic Gateway (c. 6.18 Ma) for the first small mammal exchange between Africa and Europe, as well as a single migratory wave of small mammals, filtered by their ecological preferences from this point until the end of the MSC.
The fossil shrews (Soricidae, Lipotyphla, Mammalia) from the Pliocene continental deposits of Tollo de Chiclana (Guadix Basin, southern Spain) are described. Remains of Asoriculus gibberodon, ...Blarinoides aliciae, Petenyia hungarica, Paenelimnoecus pannonicus, Myosorex meini, and an indeterminated species of Soricidae have been recognized. With the exception of A. gibberodon, these species are very uncommon in the south of the Iberian Peninsula; in fact, this finding represents the first record of Petenyia, Blarinoides, Paenelimnoecus, and Myosorex in the Guadix Basin. The changes in the abundance of Soricidae in the studied levels indicate wet and warm climatic conditions during the late Ruscinian and early Villanyian, and a decrease in the temperature and precipitation in the late Villanyian.
The gerbillid Myocricetodon is mainly known from the Miocene of Africa and Asia, but some small samples of this genus have been identified in southwestern Europe, interpreted as immigrants driven by ...the Messinian Salinity Crisis. However, the specific determination of these European populations and their relationships with African forms have proved controversial. The population from Negratín-1 (Guadix Basin, southern Spain) was attributed to the African species Myocricetodon jaegeri, but other European samples have still not been determined at the specific level. Here we describe the material of Myocricetodon from Almenara-M (eastern Spain), which represents the most abundant sample of the genus known from Europe, confirming its assignation to M. jaegeri. We also analyze material from Salobreña, Pino Mojón (southern Spain) and Castelnou-3 (southern France), concluding that these samples belong to the same species. The presence of these coeval and conspecific populations of Myocricetodon is explained by a single migratory event from northern Africa. The occurrence of Myocricetodon, interpreted as an indicator of warm and arid conditions, is restricted to southern and eastern Spain and the southeastermost extreme of France, being mainly limited to the Mediterranean coast. It is absent in other Iberian areas, such as the Granada, Cabriel and Teruel basins, despite their rich and well-studied record of late Miocene mammals. This distribution suggests the existence of different environmental (more humid) conditions in those areas during the latest Miocene, as already proposed for the Granada Basin. Our data also indicate that the presence of Myocricetodon in Europe was limited to a short interval close to the Miocene-Pliocene boundary, contrarily to other gerbils, namely Debruijnimys, which persisted during the Pliocene. This suggests that Myocricetodon could be extremely sensitive to environmental factors and its occurrence in Europe was linked to a specific moment of arid conditions.
•All the European samples of the African gerbil genus Myocricetodon are described•These populations from Spain and SE France are assigned to the species M. jaegeri.•This rodent was limited to the Mediterranean coast, being absent in inner basins.•The presence of Myocricetodon in Europe is restricted to the latest Miocene.•Myocricetodon was linked to particularly arid environmental conditions.
The Late Miocene and Pliocene continental sediments in the Granada Basin (southern Spain) have yielded large amounts of fossil small mammals in 37 localities from 11 sections. The aim of this paper ...is to integrate faunistic, stratigraphic, and sedimentary criteria to unravel the geological history of the continental infilling of the basin.
The palaeontological study has led to a detailed biozonation on the basis of rodents, which helps to correlate in detail the different sedimentary units found in the basin, and to follow the changes of the different sedimentary systems and their palaeogeographical evolution through time.
Combination of the proposed biostratigraphy and the reinterpretation of the magnetostratigraphic analyses of the Barranco del Purcal section allows us to assign an absolute age slightly older than 5.23 Ma to the Turolian–Ruscinian boundary (MN13‐MN14).
The drainage system of the Granada Basin in southern Spain has evolved from endorheic to exorheic since the basin emerged and became continental in the latest Tortonian (late Miocene). The age of ...implementation for the recent exorheic, east-west drainage can now be identified by small mammal dating. This drainage configuration began in the latest Pliocene–earliest Pleistocene due to the capture of the Genil River by a Cacín River tributary. It represented an important change in the behavior of the basin and therefore in the geomorphology, as depositional forms and processes were replaced by erosive ones. While the basin was endorheic, sedimentation was active throughout the basin. Afterward the change to exorheic and up to the present, erosion dominates and sedimentation occurs only in some small, fault-controlled depositional depocenters.
Recent study of the small mammals (rodents and insectivores) from several fossil-bearing sites situated in the central sector of the Guadix Basin (Southern Spain) has notably increased the knowledge ...of the mammal assemblages that existed in Southern Iberia from the latest Miocene to the earliest Pleistocene. On the basis of this new information, we propose a biozonation for the continental deposits of the Guadix Basin, which consists of six biozones ranging in age from the late Turolian (MN13) to the early Villanyian (MN17). These biozones, defined according to the rules of the International Stratigraphical Guide, include not only the mentioned recently discovered fossil sites, but also other, previously known, localities of the basin. Finally, we integrate the described biozones in the Neogene Mammal units and the European Land Mammal Ages, correlate them with several classical mammal sites from other Iberian basins and the rest of Europe, and establish an approximate numerical age for the lower and upper limits of each biozone.
Recently a discussion is taking place about the Scontrone (l’Aquila) and Gargano (Apulia, Italy) mammal faunas and the age of their immigration.
Mazza and Rustioni (2008) dated the Scontrone mammal ...fossils as Tortonian on the basis of their position in the
Lithothamnium Limestone and came to the conclusion that some elements of the Scontrone and Gargano faunas must have colonised the area in Oligocene or Early Miocene times.
Van den Hoek Ostende et al. (2009) disagreed with this interpretation and suggested a Late Miocene (10
Ma) age for the time of immigration. We think the arguments to place Scontrone in the Tortonian are not convincing. An analysis of the potential ancestors of each of the Gargano faunal components shows that a Messinian age for the immigration is fully compatible with the distribution of these ancestors in the European Miocene.
Récemment les faunes de mammifères de Scontrone (l’Aquila) et Gargano (Pouilles, Italie) et le moment de leur immigration ont été discutés.
Mazza et Rustioni (2008) dataient les fossiles de Scontrone comme Tortonien sur la base de leur position dans le Calcaire à
Lithothamnium et arrivaient à la conclusion que quelques éléments des faunes de Scontrone et du Gargano devaient avoir colonisé la région à l’Oligocène ou au Miocène ancien.
Van den Hoek Ostende et al. (2009), en revanche, proposaient Miocène tardif (10
Ma) pour le moment de l’immigration. À notre avis, les arguments pour placer Scontrone dans le Tortonien ne sont pas convaincants. L’analyse des ancêtres potentiels de chacun des éléments de la faune du Gargano montre qu’un âge Messinien pour l’immigration est tout à fait compatible avec la distribution de ces ancêtres dans le Miocène Européen.
The results of our study on the three murid species found in the early Pleistocene site of Loma Quemada-1, located in the Guadix-Baza basin, are reported. This site is very important from a ...palaeontological point of view because it is one of the youngest deposits of this age that records the presence of the genus
Castillomys
. Moreover, the presence of
Micromys minutus
represents one of the oldest records of that species.
A rich and diverse micromammal fauna from the late Turolian (MN13) locality of Negratín-1 (Guadix Basin, southern Spain) is described. The faunal list of this site includes Apodemus gudrunae, ...Occitanomys alcalai, Stephanomys dubari, Paraethomys meini, Myocricetodon jaegeri, Debruijnimys almenarensis, Apocricetus alberti, Ruscinomys sp., Eliomys sp., Atlantoxerus sp., Parasorex ibericus, and Soricidae indet. This is the most nearly complete mammal fauna from the Miocene of the Guadix Basin and allows precise correlations with localities from other Iberian areas. In addition, some of the taxa identified in Negratín-1 are useful as palaeoecological indicators (Myocricetodon, Debruijnimys, Atlantoxerus), evidencing warm and dry climatic conditions. But the principal interest of the fauna from Negratín-1 is the presence of several species of African origin, the gerbillids Debruijnimys almenarensis and Myocricetodon jaegeri, which are recognized for the first time in Europe. We also ascribe to M. jaegeri the population from the upper Turolian karst infilling of Almenara-M. This finding constitutes new evidence for faunal exchanges between North Africa and the Iberian Peninsula during the Messinian Salinity Crisis.
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