Mammal Neogene Zone Research Articles

Calibrating lower-middle Miocene mammal faunas and unravelling climate change during the Miocene Climate Optimum: the Bardenas Reales de Navarra record (Ebro basin, NE Iberian Peninsula)

AbstractThe chronology of lower Miocene Iberian small mammal faunas is still poorly constrained given the scarcity of well dated sedimentary successions including small mammal fossil localities. Such scarcity has prevented also an accurate understanding of the response of European terrestrial ecosystem to global changes across the Miocene climate optimum (MCO), one of the best analogues of present-day global warming. Here we present an updated fossil small mammal record of the Bardenas Reales de Navarra (western Ebro basin, Spain), where an expanded lower to middle Miocene continental succession is superbly exposed. Previous and new magnetostratigraphic results from this succession have enabled us to propose, along with additional magnetostratigraphically-dated Iberian faunas, a new chronology for local zones Y to D (Mammal Neogene zones MN2 to MN5). In addition to that, the studied small mammal faunas point to a gradual increase in temperature and humidity conditions in SW Europe between 20 and 15.5 Ma, which appears to be coupled with the progressive shift towards warmer regional (Atlantic) and global conditions across the MCO, thereby pointing to gradual changes in oceanic circulation as the main driver of this period of global warmth. The evolution of sedimentary facies appears to indicate a threshold response of the Ebro basin hydrological balance to the MCO, whereas pedogenic formation of magnetic minerals seems to be linked to periods of enhanced climate variability. These results highlight the need of combining different paleoenvironmental indicators in order to obtain a reliable view of the response of continental ecosystems to global warming.

Life in a Central European warm-temperate to subtropical open forest: Paleoecology of the rhinocerotids from Ulm-Westtangente (Aquitanian, Early Miocene, Germany)

The Ulm-Westtangente locality has yielded the most abundant vertebrate fauna from the Aquitanian stage in Germany. Its dating to the Mammal Neogene Zone 2a, a turnover in Cenozoic climate, makes it a crucial source for the understanding of faunal, paleoecological and paleoenvironmental specifics of the European Aquitanian. However, while most taxa from Ulm-Westtangente have been studied, little to no research has been conducted on the large herbivores, particularly on the two rhinocerotids Mesaceratherium paulhiacense and Protaceratherium minutum. Here, we used a multi-proxy approach to investigate the paleoecology of these two species. The remains of the smaller species P. minutum (438 to 685 kg) are twice as abundant as those of the larger M. paulhiacense (1389 to 2327 kg), but both display a similar age structure (~ 10% of juveniles, 20% of subadults and 70% of adults), mortality curves, and mild prevalence of hypoplasia (~ 17%). Results from dental mesowear, microwear, and carbon isotopes indicate different feeding preferences: both were C3 feeders but M. paulhiacense had a more abrasive diet and was probably a mixed feeder. Our study on rhinocerotids also yielded new paleoenvironmental insights, such as the mean annual temperature (15.8 °C) and precipitation (317 mm/year) suggesting rather warm and dry conditions.

Taxonomy and phylogeny of the smallest Miocene rhinocerotid Parvorhinus n. gen. (Mammalia, Rhinocerotidae)

Middle Miocene Rhinocerotini are particularly important to understand the origin and evolution of latest Miocene and then Plio-Pleistocene taxa. However, little is known about some early divergent Rhinocerotina such as ‘Dicerorhinus’ steinheimensis. A sample of a small-sized rhinocerotid from the Middle Miocene (Mammal Neogene Zone 6) locality of Devínska Nová Ves (Bratislava, Slovakia) is here described for the first time. The specimens consist of maxillae, fragment of mandibles and postcranial remains. The described specimens clearly differ from Middle Miocene representatives of elasmotheres, aceratheres and brachypotheres, but closely resemble the poorly known rhinocerotid ‘Dicerorhinus’ steinheimensis. A cladistic analysis shows that this taxon is related with the early divergent Rhinocerotina, such as Lartetotherium sansaniense and Gaindatherium browni, and it is distantly related with both Rhinoceros and Dicerorhinus. Considering the position and the peculiar morphological and morphometric features, such as smaller size with respect to other Rhinocerotini species, posterior border of the symphysis in front of p2, crochet always present on P2-P4, P1 always absent, protoloph interrupted on P2, lingual cingulum absent on M1-M2, posterior part of the ectoloph concave on M1-M2, ‘Dicerorhinus’ steinheimensis is here included in the new genus Parvorhinus.

Evolution of the carnivoran (Carnivora, Mammalia) guild structure across the Middle/Upper Miocene boundary in Germany

We analyse the evolution of carnivoran guilds (body mass, locomotor pattern, and diet preference) across the Middle to Upper Miocene boundary based on a comparison of the carnivoran fauna from Steinheim (Mammal Neogene zone MN 7/8; Servallian to early Tortonian), and from the Eppelsheim Formation (Mammal Neogene zone MN 9/10; mid-Tortonian), Germany. Results reveal a massive faunal turnover between these two communties due to taxonomic differences up to the family level. Guild structures of both carnivoran faunas were similar, implying that Late Miocene taxa replaced Middle Miocene taxa in their respective niches rather than new ecological strategies being added to the guild. This is not surprising, as (1) the majority of Late Miocene taxa were derived from European Middle Miocene ancestors and mostly share their paleoecology, (2) of the few undisputed Late Miocene immigrant taxa (Eomellivora, Simocyon, Sivaonyx), only Eomellivora adds new ecological strategies to the guild, and (3) both faunas occupied the same kind of partly open woodland paleoenvironment. Our paper supports previous studies, suggesting that ecological diversity remains stable across the Middle to Upper Miocene boundary and that similar environments produce similar carnivoran guild structures irrespective of taxonomical composition.

Revision of the plant assemblage of Steinheim am Albuch (Baden- Württemberg, Germany, middle Miocene, reference locality of Mammal Neogene Zone MN 7)

Revision of the plant assemblage of Steinheim am Albuch (Baden- Württemberg, Germany, middle Miocene, reference locality of Mammal Neogene Zone MN 7)

FOSSO DELLA FITTAIA: THE OLDEST TUSCO-SARDINIAN LATE MIOCENE ENDEMIC VERTEBRATE ASSEMBLAGES (BACCINELLO-CINIGIANO BASIN, TUSCANY, ITALY)

The late Miocene continental successions of the Baccinello-Cinigiano basin (Grosseto), one of the longest and most continuous vertebrate-bearing continental successions in the Neogene Italian record, yielded at least four superimposed vertebrate assemblages bracketed in the time span 8.3 - 6.4 Ma. The Baccinello-Cinigiano basin is famous for recording endemic vertebrate assemblages that include the youngest European Miocene hominoid, Oreopithecus bambolii . The late Miocene endemic vertebrate fauna known as the Baccinello V0 assemblage is the oldest vertebrate fauna within the Baccinello-Cinigiano basin succession, being correlated to the European mammal Neogene unit MN11. Recent field surveys along the Trasubbie river allowed studying in detail the basal Baccinello-Cinigiano sedimentary succession, and sampling fossiliferous level bearing microvertebrates along the small creek Fosso della Fittaia. The sample “Fosso della Fittaia 2013” yielded about 170 fossil remains improving our documentation of the oldest vertebrate assemblages from the Baccinello-Cinigian basin. As far as rodents are concerned, in addition to the already recognized murid Huerzelerimys and glirid Anthracoglis , a few dental remains are assigned to a new genus and species of giant dormouse. It is further worth noting the occurrence in the sample of shrew remains (the first described from the Baccinello-Cinigiano basin) identified as cf. Lartetium . The latter attests the presence of a crocidosoricine in the Fosso della Fittaia 2013 assemblage, postdating the youngest known occurrences of the subfamily by at least 1 my. The vertebrate assemblage is completed by a diverse herpetofauna and the first fish remains reported from the basin.

Perforations of Freshwater Snail Shells from the Miocene of Germany: Nihilichnus covichi n. isp.

ABSTRACTFormerly unknown holes in shells of freshwater gastropods are described and assigned to the ichnogenus Nihilichnus. The smaller size range, the different substrate, and the sometimes present scratchings around the holes distinguish our praedichnion from the type ichnospecies N. nihilicus, and we propose N. covichi n. isp. for the herein presented material. The type material of N. covichi n. isp. derives from the middle Miocene (Mammal Neogene zones MN6 and MN7) lake sediments of the Steinheim Basin (Steinheim am Albuch, SW Germany); the holes occur in shells of Gyraulus trochiformis (Planorbidae) and Bania pseudoglobulus (Hydrobiidae). Further material consists of perforated shells of Nematurella bavarica (Hydrobiidae) and Galba armaniacensis (Lymnaeidae) from the early Miocene Kirchberg Formation (MN 4; SE Germany). In contrast to the other morphologically similar but marine praedichnia (e.g., Belichnus and Oichnus, recently synonymized with Sedilichnus), Nihilichnus is known from terrestrial, palustrine, freshwater (reported herein), and marine environments. Nihilichnus covichi n. isp. was probably produced by the pharyngeal teeth of durophagous tench fish (Tinca spp.; Cyprinidae).

Paleobiogeography of Early/Middle Miocene terrestrial gastropods in Central Europe: An approach using similarity indices

Terrestrial gastropods are a common faunal element in continental Miocene fossil Lagerstätten of Europe. Although having lived during a time span that includes the Miocene Climatic Optimum and the devastating Ries/Steinheim meteorite impacts, the state of knowledge about their faunal composition and geographic distribution is surprisingly incomplete. The land snail faunas of 30 different Early and Middle Miocene deposits of Central Europe (European Mammal Neogene zones MN 4 to MN 8) were compared using statistical methods (cluster and NMDS analyses, using the Ochiai, Simpson and Kulczynski indices). This includes 300 different taxa identified so far. Most of the analyzed deposits were part of the Miocene Paratethys and are today located in France, SW Germany (Baden-Württemberg state), SE Germany (Bavaria state), Austria, Poland, and Hungary. Cluster analyses resulted in different clusters, the majority of which can be explained by their geographic situation and/or by their distribution in time (e.g., the consistently recovered Baden-Württemberg and Bavaria clusters and the Bakony Mountains cluster). The remaining clusters cannot be fully explained so far, but some possibilities are explored here. Our results reveal the power of a solid taxonomic framework as a basis for palaeobiogeographic studies. As such, more “basic” palaeontological studies are required to strengthen future analyses.

New gastropod assemblages from the Early/Middle Miocene of Riedensheim and Adelschlag-Fasanerie, southern Germany

This work presents a taxonomic study and paleoecological reconstructions of the continental gastropod assemblages from two new Miocene localities in the German part of the North Alpine Foreland Basin, Bavaria. Riedensheim (next to the town of Rennertshofen) and Fasanerie (next to the town of Adelschlag). The fossil rich deposits belong to the Upper Freshwater Molasse (OSM), correlated to the regional biostratigraphic unit C+D (Burdigalian/Langhian;MN 5 in the European mammal Neogene zone). 17 gastropod species (almost exclusively pulmonates) were found in Adelschlag-Fasanerie and 35 species in Riedensheim. 13 species are shared by both assemblages. Of these, the following species have their distribution expanded in Germany: Azeca peneckei, Carychium (Carychium) galli, Vitrea ammoni and Urticicola perchtae;and possibly also Stagnicola cf. praebouiletti and Truncatellina cf. pantherae. Paleoecological reconstructions indicate a rich freshwater gastropod community in Riedensheim, with a well-vegetated area immediately surrounding the water body (which diminished in size with time), and a surrounding environment dominated by humid forest. The fauna from Adelschlag-Fasanerie, which was much impoverished in comparison, might represent flood plain and fluvial channel deposits. Finally, a comparison to the molluscan faunas of coeval and nearby localities (Adelschlag, Attenfeld, Sandelzhausen and Undorf) is provided.

The fossil pulmonate snails of Sandelzhausen (Early/Middle Miocene, Germany): Ellobiidae, Pupilloidea, and Clausilioidea

Sandelzhausen is an Early/Middle Miocene (Mammal Neogene zone MN5) fossil site near Mainburg, S Germany, that despite its small size harbors a rich fossil record. Thousands of fossil continental mollusks, almost exclusively pulmonate snails, were recovered during the excavations, but did not receive much attention from researchers. Here, the first part of a formal taxonomic treatment of Sandelzhausen’s fossil pulmonates is presented, dealing with the superfamilies Ellobioidea, Pupilloidea, and Clausilioidea, and including the description of a new species. The following species were found in the material: Carychium eumicron and Carychium galli sp. nov. (Ellobiidae); Granaria cf. grossecostata and Granaria sp. (Chondrinidae); Gastrocopta acuminata and Gastrocopta nouletiana (Gastrocoptidae); ?Pyramidula sp. (Pyramidulidae); Strobilops sp. (Strobilopsidae); Vallonia lepida (Valloniidae); Vertigo callosa (Vertiginidae); Pseudidyla moersingensis (Clausiliidae); Triptychia sp. (Filholiidae).

The fossil pulmonate snails of Sandelzhausen (Early/Middle Miocene, Germany): Succineidae, Testacelloidea and Helicoidea.

Sandelzhausen is an Early/Middle Miocene (Mammal Neogene zone MN5) fossil site near Mainburg, S Germany, and despite its small size it harbors a rich fossil record. Hundreds of fossil continental mollusks, almost exclusively pulmonates snails, were recovered during the excavations, but never received due attention by researchers. Here, the second part of a formal taxonomical treatment of the fossil pulmonates from Sandelzhausen is presented, dealing with the superfamilies Succineoidea, Testacelloidea and Helicoidea, and including the description of a new hygromiid species. The following species were found in the material: Succinea minima (Succineidae); Palaeoglandina sp. (Spiraxidae); Testacella zellii (Testacellidae); Klikia cf. coarctata (Elonidae); Cepaea cf. eversa, Cepaea cf. sylvestrina and Tropidomphalus cf. incrassatus (Helicidae); ?Helicodonta sp. and Helicodontidae indet. (Helicodontidae); Leucochroopsis kleinii and Urticicola perchtae sp. nov. (Hygromiidae).

Updated Aragonian biostratigraphy: Small Mammal distribution and its implications for the Miocene European Chronology

This paper contains formal definitions of the Early to Middle Aragonian (late Early–Middle Miocene) smallmammal biozones from the Aragonian type area in North Central Spain. The stratigraphical schemes of two of the best studied areas for the Lower and Middle Miocene, the Aragonian type area in Spain and the Upper Freshwater Molasse from the North Alpine Foreland Basin in Switzerland, have been compared. This comparison allows the analysis of the order of shared mammal events in the two countries, and the quantification of the resulting asynchronies based on their temporal correlations. The order of the events is very similar in Spain and Switzerland. In order to estimate the diachrony, two age-model options are used for the Swiss record. Our preferred option yields no discrepancies with SW European paleomagnetic and radiometric calibrations of the Ramblian and Early Aragonian bioevents. All Swiss first taxa occurrences precede those in the Aragonian type area by 0.74Myr on average. The asynchronies (1-2Myr) of the species arriving in the late Middle to early Late Aragonian may be higher than in the Early Aragonian (0-1Myr). The implications for the biochronological mammal Neogene system are discussed. Evidence is given confirming the unfeasibility of a formal European biozonation, since it is realised, that 1) most indicator species and many genera of rodents yielding the most detailed zonations have limited geographical ranges hampering recognition of the mammal Neogene zones; and 2) first and last taxon occurrences are diachronical. Therefore, the mammal Neogene system based on a sequence of time-ordered reference localities is preferred to the one based on selected bioevents “developed in widespread geographic areas”.

U–Pb geochronology of zircons from fossiliferous sediments of the Hajnáčka I maar (Slovakia) – type locality of the MN 16a biostratigraphic subzone

AbstractLacustrine sediments of the Hajnáčka I maar of southern Slovakia contain teeth and skeletal remains of a mammal fauna, including index Early Villanyian arvicoline rodents. U–Pb dating of magmatic zircons extracted from the redeposited fossiliferous maar sediments revealed a total of six volcanic events. The oldest age of 3.43 Ma was interpreted as that corresponding to the initial phreato-magmatic eruption that created the maar. Most zircons grouped around 3.06 ± 0.03 Ma, the age attributed to the catastrophic eruption that killed the mammal assemblage thriving within and around the maar studied. This age coincides with the 3.1 Ma boundary between the MN 16a and 16b subzones of the European Mammal Neogene chronostratigraphic scale estimated from the succession of Early Villanyian palaeontological localities according to the hypsometry of rodent teeth. Younger zircon ages overlapped those of the neighbouring basaltic lava flows, necks and dykes, thus recording superimposed effusions. The youngest 1.58 Ma old zircon defines the age limit for the final redeposition of the fossiliferous sediments in the maar drainage lake regime.

The European Far West: Miocene mammal isolation, diversity and turnover in the Iberian Peninsula

AbstractAim To analyse the diversity dynamics of Miocene mammalian faunas in the Iberian Peninsula in order to determine whether the patterns are related to the dispersal of taxa from other areas into this region.Location Mainly the Iberian Peninsula, but two close geographical areas (Central Europe and the Eastern Mediterranean) are also considered in some of our calculations.Methods Genus‐level faunal lists for a total of 299 localities from the Iberian Peninsula, covering 10 successive biochronological units [Mammal Neogene (MN) zones] that span from the latest Early Miocene to the early Pliocene (about 17–4 Ma), were compiled. The dataset was expanded with a further 331 localities in Central Europe and the Eastern Mediterranean for the same time span. Next, a taxonomically standardized database was used to create composite faunal lists of micro‐ and macromammalian genera present during each MN zone. Separate genera‐by‐MN‐zone matrices for both micro‐ and macromammals were built for each region. Mean standing diversity as well as origination and extinction rates were calculated for the Iberian Peninsula, and their correlation with preservation rates is discussed. Simpson’s coefficient of faunal similarity with Central Europe and the Eastern Mediterranean was calculated in order to evaluate whether diversity patterns were related to changes in the affinity of the Iberian mammalian faunas with those of other regions.Results Diversity changes in the Iberian macromammalian faunas coincide with periods of increased faunal similarity with other regions, suggesting a relationship to the expansions and contractions of the geographical ranges of the constituent taxa. This pattern is not recognized for micromammals; that is, their diversity trends are not related to changes in geographical ranges.Main conclusions Climatic shifts result in expansions or contractions in the geographical ranges of macromammals, owing to changes in the distribution of their preferred habitats. The lower dispersal ability of micromammals results in a higher extinction risk when habitat fragmentation confines their populations to relatively small environmental patches. Hence, they are more severely affected by climatic changes. Our results thus emphasize the role of climatic forcing in mammalian biogeography and diversity.

Predictable structure of Miocene insectivore (Lipotyphla) faunas in Western Europe along a latitudinal gradient

The insectivores (Grandorder Lipotyphla) have been seldom used in mammal-based paleoenvironmental inferences because this group is generally considered insufficiently represented or studied. Nevertheless, a recent compilation on the insectivore record of Western Europe has shown that this is not the case. From the insectivore occurrences themselves a major paleobiogeographical pattern seems to be present: the faunas of the Mediterranean regions of Western Europe are poorer and seem to be a subset of those occurring at higher latitudes. This kind of pattern, where smaller assemblages seem to be a ‘nested subset’ of the richer ones, is known as nestedness. In this work we analyze the prevalence of nestedness in the Miocene insectivore record of western Europe. The calculations are carried separately for each MN (Mammal Neogene) zone and a measure of nestedness or order is given. The probability that a similarly nested pattern could be obtained at random for each MN is assessed by permutation. Our results show the prevalence of nestedness in all the MN zones except the MN 1. In the second step, we study the causes of nestedness. A significant correlation of the nested structure with latitude is found in 8 out of 12 matrices, thus confirming that the southern assemblages are a subset of the northern ones. This must be related to some underlying latitudinal gradient that already existed during the Miocene. Latitudinal gradients in temperature seem to have been unimportant until the Late Miocene yet the nested pattern existed as early as the Early Miocene. A precipitation gradient, which was already present by the Early Miocene, seems to be the most important structuring factor. Independent evidence has confirmed that the Central European regions were more humid than the Mediterranean ones thus explaining the higher diversity of insectivores in that area as this group is more diverse in humid climates. The structure of the southern assemblages is a highly predictable subset of that of the northern ones. In the south the species that seem to have required higher levels of environmental moisture are missing. This applies for instance to many talpids and dimylids which never reached the Iberian Peninsula.

Gliridae (Rodentia, Mammalia) with a simple dental pattern: a new genus and new species from the European Early and Middle Miocene

A new genus of Gliridae, Simplomys gen. nov. is proposed. It contains glirids with a simplified dental pattern from the European Early and Middle Miocene. Simplomys gen. nov. includes several species originally described as Pseudodryomys such as Simplomys simplicidens, Simplomys robustus, Simplomys julii, and Simplomys aljaphi. In addition, a new species, Simplomys meulenorum sp. nov., is proposed from the Spanish Miocene. The species of this genus share not only a very reduced and simplified dental morphology, but also unique dental proportions that clearly separate them from any other genera of Gliridae. Simplomys gen. nov. is recorded in most of the fossil faunas from the Early and Middle Miocene of the Iberian Peninsula, and shows the maximum diversity in this area during Mammal Neogene Zones MN 3 and MN 4. The genus has been also recorded in other European countries such as France, Germany, and Switzerland, conferring to this very characteristic taxon an important role for biochronological correlations within the European continent. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157, 622–652.

Chemical zonation and relative timing of growth sections in garnets from eclogites of the Leaota Massif, South Carpathians

AbstractWe have investigated the chemical zoning of garnet in three texturally different eclogite types from the Leaota Massif, Romania, to test the various zonation patterns of Ca, Fe, Mg and Mn as indices of time-lines in porphyroblastic garnets. Mn zonation was found to mark various growth stages very well. It indicates in each of our three case studies a complex growth history dominated by multiple nucleation and coalescence, but also interrupted by partial resorption, as shown by morphological characteristics. Chemical variations of the main elements in garnet during prograde high-pressure metamorphism define time-lines other than those of Mn which decrease, highlighting the stages of porphyroblastic growth. In particular, the Ca/Mn, Mg/Mn and Mg/Fe ratios are useful in late growth stages, when low Mn contents and radial gradients do not allow a satisfactory resolution of Mn time-lines. These ratio-based time-lines further substantiate the potential of Mn time-lines in revealing non-concentric porphyroblastic growth. This is important in order to correctly relate garnet growth stages to stable mineral assemblages, a prerequisite for a reliable derivation of the metamorphic history of the host rock.

Neogene Murinae of Ukraine (Mammalia, Rodentia)

Presented here is the taxonomy and biochronological sequence of Ukrainian Murinae, based on remains from 21 fossil sites. The succession covers the period from the mid Sarmatian through Kuyalnikian Eastern Paratethys Stages, here correlated with the Late Vallesian through Late Villanyian European Mammal Units (European Mammal Neogene Zones MN 10-17).Progonomys cathalai appeared first, followed byHansdebruijnia perpusilla and twoApodemus “lineages” of different size (MN 11).Castromys nadachovskii n. sp. has a single record of mid Turolian age. The generaRhagapodemus andMicromys appeared in the Late Turolian, andOccitanomys (Rhodomys) andOrientalomys during Ruscinian time. Paleozoogeographic relations of Ukrainian Murinae are mainly with the European Meditarranean region, Central and East Asia, and Anatolia. Faunas from the eastern Mediterranean region (e. g., Maramena, Greece) appear to be most suitable for regional biochronological correlations.

The upper Miocene mammal record from the Teruel-Alfambra region (Spain). The MN system and continental stage/age concepts discussed

ABSTRACT An extended and revised mammal succession of 99 fossil localities from the Upper Miocene sediments of the Teruel-Alfambra region (NE Spain) is presented. An updated biozonation is proposed. The biostratigraphic justification for the correlation of the magnetic polarity patterns of the La Gloria, El Bunker, Masada Ruea, Masada del Valle and Masía de la Roma sections to the Geomagnetic Polarity Time Scale (GPTS) is discussed. A comparison with Late Miocene faunas from elsewhere in Europe demonstrates that faunal resemblance across the continent is very low. As illustrated by an analysis of the “Progonomys event,” local appearances of genera may be strongly diachronous and even species should not a priori be assumed to be isochronous at resolutions higher than several hundred thousands of years. These observations have implications for European continental stratigraphy and chronology: (1) The usefulness of the European mammal-based Stages/Ages can be doubted because their biostratigraphic significance is mainly local, and because more and more direct calibrations of mammal faunas to the numerical time scale are becoming established; (2) The European Mammal Neogene (MN) system, currently defined as a series of 16 time-ordered faunas, should not be divided into sub-units, because this weakens its power for cross-continental faunal correlation. In addition, the use of MN “boundaries” is erroneous and misleading, both from a philosophic and technical point of view.

A calibrated mammal scale for the Neogene of Western Europe. State of the art

A magnetobiostratigraphically calibrated mammal scale for the Neogene of Western Europe is presented in this paper. The Mammal Neogene (MN) units originally proposed by Mein [Report on activity RCMNS-Working groups (1975)] have been re-defined here on the basis of first appearances of selected small and large mammal taxa. The chronology of the lower boundaries of each unit had been established mostly after the significant magnetobiostratigraphic framework developed in the last decade in a number of Spanish basins: Ebro, Calatayud–Daroca, Vallès–Penedès, Teruel, Fortuna, Cabriel and Guadix–Baza. In the case of the early and middle Miocene (particularly, MN 1, MN 2 and MN 3), the authors have also taken into account the magnetobiostratigraphic framework developed in the North Alpine Foreland Basin. Some alternative correlations of the magnetostratigraphic data from this last basin are proposed in order to achieve a higher degree of consistence with the data from the Iberian basins. A quite well established magnetostratigraphic calibration of the MN boundaries can be proposed for most of the Neogene, from Middle Miocene to Late Pliocene. On the other hand, the chronological boundaries of the Early Miocene MN units are still poorly constrained due to: (1) scarcity of well-studied, continuous, thick magnetostratigraphic sections; (2) the difficulty in defining the boundaries of the MN zones for this time-span due to the relative homogeneity and persistence of the fossil rodent faunas and the absence of significant large mammal dispersal events. Some of the troubles which arise with the application of the MN units strengthen the need to take into account the palaeobiogeographical meaning of these units and their real suitability to date and correlate through extensive geographic areas.