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The number of late Neogene Spanish micromammal-containing continental sections with a correlation to the Geomagnetic Time Scale is steadily growing. Nonetheless, well-calibrated sections with dense micromammal records are still rare, biostratigraphic correlations between basins are not straightforward, and ages of uncalibrated sites are poorly constrained. Here, we aim at improving the chronology of Iberian micromammal sections and sites for the interval 8.5–2 Ma by: (i) analyzing qualitative and quantitative similarities between rodent assemblages and turnover in the different basins, (ii) formulating a system of fifteen Iberian assemblage biozones, and (iii) constraining the ages of zone boundaries, assuming isochroneity across basins. Age uncertainty ranges for most known Iberian micromammal sites are obtained by combining regional biozone boundary ages with local magnetostratigraphic records, sedimentation rates and/or evolutionary rates. In addition, our results include new, integrated stratigraphic records from the Jumilla-La Celia and Teruel Basins, which are used to constrain the thus far poorly dated interval covering the latest Tortonian and earliest Messinian (8–7 Ma). [ABSTRACT FROM AUTHOR]

Mortality curves of extinct rodents can be reconstructed by using relative wear calculated from the amount of dentine exposed. MicroCT scanning of molars of the extinct Eomyid genus Ligerimys shows that this Wear Index increases gradually with wear; this means that wear classes can serve as a proxy for age and can therefore be used to reconstruct mortality curves. We reconstructed mortality curves of three species of Ligerimys from the late early Miocene of Spain. These curves show a similar trend, with decreasing numbers of molars as the amount of wear in each class increases. The curves show remarkable similarities to those of the wood mouse Apodemus. This suggests that Ligerimys was, like Apodemus, at the fast end of the fast-slow continuum, in other words r-selected, though not as extreme as some other rodents. [ABSTRACT FROM AUTHOR]

Lithofacies belonging to mud-flat and palustrine deposits (lake margin) in the Miocene of the Madrid Basin (Spain) have been studied. Four lithofacies corresponding to mud flat (1 and 3) and palustrine (2 and 4) deposits have been differentiated. Units 1 and 3 consist mainly of mudstones and carbonates (calcretes and diolocretes). The clay fraction is dominated by trioctahedral smectite (up to 79%) with illite and kaolinite as minor components. The d(060) spacing value shows reflections at 1.52 and 1.50 Å indicating also the presence of dioctahedral phyllosilicates. Unit 2 consists predominantly of lutites (claystones), locally with carbonate and chert nodules. The clay fraction is dominated by sepiolite (up to 96%) with variable contents of smectite and subordinate illite. The d(060) spacing value shows reflections at 1.51 and 1.52 Å indicating trioctahedral clay minerals. Unit 4 consists mostly of carbonates (limestones) with mudstone and lutite inserts. The clay fraction shows different contents of sepiolite, palygorskite and dioctahedral smectite. The analysis of a selection of trace elements (Cr, Co, Th, La, Sc) has allowed us to determine the characteristics of the source area as dioritic, somewhat different from those of the nearby materials from the Batallones sector. Sepiolite shows FWHM values ranging between 0.68 and 1.10 (2θ), indicating "low crystallinity sepiolite". Differences in the conditions of formation of magnesian smectite and palygorskite have been observed in the mud-flat and palustrine deposits. The formation of sepiolite mainly by neoformation in palustrine deposits with different hydrochemistry is remarkable, leading to differences in fibre size and crystallinity of the fibrous clay mineral. Authigenic transformation processes from previous Al-rich phases would be responsible for the formation of saponite and palygorskite in mud flat and palustrine environments, with different pH conditions. [ABSTRACT FROM AUTHOR]

The phylogenetic relationships of the small-bodied catarrhine Pliobates cataloniae (∼11.6 Ma, NE Iberian Peninsula) have been controversial since its original description. However, the recent report of additional dentognathic remains has supported its crouzeliid pliopithecoid status. Based on the available hypodigm, the molar enamel-dentine junction (EDJ) shape of P. cataloniae is compared with that of other pliopithecoids from the same basin as well as both extinct and extant hominoids to further evaluate its pliopithecoid affinities. We also quantitatively compare the EDJ shape among these taxa by means of landmark-based three-dimensional geometric morphometrics using principal component analysis (PCA), canonical variate analysis, and between-group PCA. Permutation tests are performed to test whether Pliobates variation exceeds that of extant hominoid genera. Results indicate that Pliobates is similar in molar EDJ shape to other pliopithecoids, particularly crouzeliids. The variation displayed by Pliobates upper molars is less marked at the EDJ level than at the outer enamel surface, probably owing to differential enamel wear and intraspecific differences in enamel thickness. Multivariate analyses of EDJ shape show that all pliopithecoids (including Pliobates) cluster together in the PCAs, canonical variate analyses, and between-group PCAs and occupy a different portion of the morphospaces from extinct and extant hominoids. Posterior and typicality probabilities strongly support the classification of Pliobates as a pliopithecoid, wheras permutation tests fail to reject the single-genus hypothesis for the P. cataloniae hypodigm. We conclude that P. cataloniae is a crouzeliid pliopithecoid, as recently supported by cladistic analyses of craniodental characters, and that previous cladistic results that supported a stem hominoid status are attributable to postcranial convergences with crown hominoids. Our results further highlight the potential of three-dimensional geometric morphometrics analyses of the EDJ shape for better informing fossil primate alpha-taxonomy by means of quantitatively testing hypotheses about tooth shape variation., Competing Interests: Declaration of competing interest There is no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study evaluates variations in petrophysical properties within a mixed alluvial to lacustrine carbonate system (Miocene, Madrid Basin, Central Spain). The transition from alluvial environments to lake margins settings displays a shift from alluvial, siliciclastic red sandstones and mudstones to palustrine–lacustrine mudstones to packstones. Fluctuations in lake‐water level enabled land plants to occupy the lake margins during periods of low lake levels. The palustrine carbonates include features like pseudo‐microkarst, nodular and mottled limestones; the lacustrine deposits include enlarged root cavities, desiccation cracks and channel bodies. Scarce fresh water biota comprises charophytes, gastropods and ostracods. The sediments possess high natural, irregular varying, gamma‐ray values at the alluvial–lacustrine transition, and low, but constant values at full lacustrine sites. Acoustic properties agree with lithological variations within individual facies. Porosity is the most important parameter influencing P‐wave and S‐wave velocities. The scatter in the velocity–porosity relationship links to the porosity type; macro‐porosity or microporosity. The wide range of pore types and pore sizes results in a weak porosity to permeability relationship for the carbonate‐dominated rocks with low permeability for microporous and high permeability for macro‐porous carbonates. The sandstones (probably only inhibiting interparticle porosity), and to a lesser extent the sandy wackestones to packstones, show quite a strong relationship between porosity and permeability. Elastic properties of mixed alluvial–lacustrine deposits (this study) and marine deposits (literature data) overlap as variations in pore structures and porosity values are similar. Only 16% of the marine and lacustrine carbonate sediments display Equivalent Pore Aspect Ratio values above 0.2. In travertine deposits, 83% of the samples exceed Equivalent Pore Aspect Ratio values above 0.2, which highlights that travertine deposits are dominated by larger Equivalent Pore Aspect Ratios compared to lacustrine and marine carbonate deposits. Travertines display other rock frameworks with different pore types, pore distribution and amount of porosity. [ABSTRACT FROM AUTHOR]

The Campisano Ravine in the Ribesalbes-Alcora Basin (Spain, early Miocene, biozone C, MN 4) yielded a relatively diverse assemblage of squirrels, composed by the ground squirrels Heteroxerus rubricati, Atlantoxerus blacki and Aragoxerus sp. the marmotines Palaeosciurus cf. sutteri, Spermophilinus sp., Marmotini indet. and the flying squirrel Aliveria cf. luteyni. Heteroxerus rubricati, Atlantoxerus blacki and Spermophilinus are typical early Miocene species from the Iberian Peninsula, and in this work we increase the knowledge of the variability of them. In MN4, the genus Aragoxerus is reported for the first time in the Iberian Peninsula, and, apart from France, it is its only record in Europe. We report here the first record of the species Palaeosciurus cf. sutteri in the Iberian Peninsula, and one of the oldest in Europe. The occurrence of Aliveria cf. luteyni marks the first record of the genus Aliveria in Western Europe. Additionally, the palaeoecological significance of this assemblage is discussed. [ABSTRACT FROM AUTHOR]

Two new fossil charophyte species from middle Miocene lacustrine deposits of Moneva (Ebro Basin, NE Spain) are described and illustrated. Sphaerochara miocenica nov. sp. is represented by medium sized gyrogonites with a characteristic spheroidal shape and ornamented with numerous small and regularly spaced tubercles arranged along the spiral cells. Several specimens show an unusual carbonate encrusted layer that covers completely or partially the gyrogonite. Psilochara monevaensis nov. sp. is characterized by large gyrogonites, with typical prolate shape and protruding apical poles. A second population of S. miocenica nov. sp. from a distant early upper Miocene lacustrine basin located in the Middle East (Bekaa Valley, Lebanon), identified in a previous study as Sphaerochara sp., is described and illustrated here, allowing the comparison of these distant populations. Ecologically, the associated fauna and facies from both localities suggest that these taxa grew in very shallow athalassic lakes. Interestingly, S. miocenica nov. sp. having a wide geographic distribution in peri-Mediterranean lakes with variable salinity, may become a fossil guide for the Miocene, providing at the same time important palaeoecological information. [ABSTRACT FROM AUTHOR]

In this paper, we study a sample of cranial, mandibular and dental remains of two species of the machairodontine felid genus Machairodus from the Early Vallesian (MN 9, around 10 Ma) site of Los Valles de Fuentidueña (Segovia, Spain): the tiger-sized Machairodus aphanistus, and the smaller and more primitive M. alberdiae; a species which is only known from this site. The fossils of these two sympatric populations are compared with the most abundant samples of M. aphanistus from the Late Vallesian (MN 10), younger sites of Batallones-1 and Batallones-3 (Torrejón de Velasco, Madrid, Spain). The results support the specific separation of M. alberdiae from M. aphanistus based on several differences in teeth size and proportions. Besides this, we observed differences among the analysed samples of M. aphanistus, indicating a differentiation between the older and more primitive form from Los Valles de Fuentidueña, and the younger and more derived one from the two Batallones sites. These differences fit well with the morphological evolution of this lineage towards the more derived Turolian Amphimachairodus giganteus. Finally, a relatively structured, patched habitat, combining the presence of open landscapes with shrubby and wooded areas, is inferred to explain the sympatric distribution of these two large machairodontines in Los Valles de Fuentidueña. [ABSTRACT FROM AUTHOR]

The locality of El Caracolar in the Granada Basin (Central Betic Cordillera, southern Spain) has yielded a rich late Miocene assemblages composed of marine invertebrates and vertebrates, accompanied by microfossils, macroflora and trace fossils. Exposed strata consisting of sands, sandy siltstones, silty sandstones, siltstones and calcirudites are divided into four local units. Lithostratigraphically, the studied section is placed between the top of the La Peza Formation and the Quéntar Formation. Based on foraminifers, the age of units 2 and 3 is estimated to be early Tortonian (11.0–9.9 Ma), whereas units 1 and 4 do not yield any reliable biostratigraphic markers. The diverse biotic association suggests that deposition took place in a near-shore outer neritic zone of a narrow to open seaway in a mesotrophic regime, responsible for the establishment of a chemosynthetic community under (sub)tropical conditions. The palaeo-depth of the depositional setting is estimated between 70 and 130 m. We further focused on decapod crustaceans that represent the first formally reported fossil decapod assemblage from the Granada province. The faunule consists of eight genera from two assemblages representing different palaeoenvironments. The assemblage of units 1 and 4 is dominated by the ghost shrimp “ Callianassa ” cf. almerai and accompanied by the hermit crab Petrochirus , whereas the assemblage from unit 3 includes the ghost shrimp Ctenocheles and the brachyuran crabs Raninoides , Calappa , Goneplax , Styrioplax , and Typilobus . Unit 2 does not yield any identifiable decapod remains. Styrioplax sp. represents the first occurrence of the genus outside the Central Paratethys, substantially expanding its palaeogeographical distribution. The decapod faunule from El Caracolar shows affinities with assemblages from the Proto-Mediterranean and Paratethys. This study provides a lithostratigraphic and palaeoenvironmental framework for further palaeontological studies in this unique Western Mediterranean outcrop. [ABSTRACT FROM AUTHOR]

From a mineralogical point of view the La Unión ore field (SE Spain) can be regarded as an oddity as some of its hydrothermal, stratabound type deposits display an extremely unusual paragenesis comprising magnetite ± greenalite ± minnesotaite ± siderite and galena ± sphalerite (IOSC - LZS). Recent mineralogical studies have shown that this paragenesis is also present at the neighboring Mazarrón ore field. These ore fields share a similar geologic setting, involving metamorphic and sedimentary rocks (Paleozoic s.l. to Permian) hosting late Miocene high-K calc-alkaline volcanic and subvolcanic rocks. The latter have andesitic to dacitic composition, and triggered hydrothermal activity and ore deposition. This study discusses the detailed mineral chemistry of magnetite samples from Mazarrón and La Unión and provides some hints for the origin of the IOSC - LZS paragenesis. We performed electron microprobe (EPMA) analyses in magnetite samples from La Unión and Mazarrón to determine the contents of minor and trace elements (Zn, Ni, Mn, Cr, V, K, Ca, Ti, Al, Si, Mg). Given that some results fell below the detection limit for the EPMA instrumental conditions we used robust regression on order statistics (robust ROS), with the NADA package in R to deal with these data sets. The Ca + Al + Mn contents in magnetites from San Cristóbal and Emilia are equivalent to the mean contents of those of IOCG, Kiruna, BIF, Cu porphyry, skarn, VMS, hydrothermal and clastic Pb-Zn deposits, but they are low in Ti + V and Ni + Cr. The principal components analysis indicates that Zn, Ni, Cr, V, K, Ca, Ti, and Mg are roughly collinear, therefore correlated, being also independent from Fe. Besides, the function discriminant analysis of data shows that the magnetites from Emilia and San Cristóbal cluster in differentiated groups, thus probably reflecting some differences related to the distance to the magmatic source that triggered the hydrothermal system: proximal in the case of San Cristóbal and distal in Emilia. [ABSTRACT FROM AUTHOR]

In this paper, we describe a previously unknown species of the glirid Eliomys from the Late Miocene and Early Pliocene Cabriel, Alcoy and Granada basins of southeastern Spain. Eliomys yevesi sp. nov. is characterized by its relative small size, narrow lingual wall and common presence of two centrolophs in the upper molars, and well-developed centrolophids in the lower molars. The new species is the probable ancestor of E. intermedius, which in turn represents the ancestor of the extant E. quercinus. According to its morphologic and biometric features, the origin of E. yevesi sp. nov. is likely to be found in some population of E. truci from the Late Miocene. Based on these affinities, we propose the lineage E. truci-E. yevesi sp. nov.-E. intermedius-E. quercinus, in which there is a trend towards the development of centrolophs, as well as the reduction of accessory crests. [ABSTRACT FROM AUTHOR]

Marine invertebrate borings are very rare in crystalline rocks, providing evidence of particular strategies producers use to colonise these unfavourable substrates. In the Sorbas Basin (Almería, southern Spain), Upper Miocene transgressive successions contain blocks of metamorphic and igneous rocks of the Nevado–Filabride Complex of the Betic Cordillera. Ichnological analysis of the embedded blocks shows the presence of two types of macroborings located in gneiss boulders, revealed to be an extraordinary case worldwide. The most abundant are regular hemispherical depressions ascribed reservedly to the well-known, mostly bivalve boring Gastrochaenolites. The second one is a pouch-like depression, tapering downward, elliptical in outline, and clearly different to other non-circular-in-outline, pouch-shaped macroborings. Thus, a new ichnogenus and ichnospecies Cuenulites sorbasensis has been defined. According to the overall shape, an endolithic or semi-endolithic bivalve using chemical means to bore is suggested as the tracemaker. Colonisation could be determined by sea-level coastal dynamics, with decreasing energy during advancing transgression allowing boring, which was then stopped due to supply of fine-grained sediment that killed the borers. [ABSTRACT FROM PUBLISHER]

Fossil mammal sites of late Miocene age ( ca 9 Ma) occur in hourglass-shaped, non-interconnected cavities up to 15 m deep, hosted in mudstone (mostly sepiolite), chert and carbonate bedrock in Cerro de los Batallones. This paper provides a model for the sedimentary infilling of the cavities, which functioned as traps for vertebrate faunas and contain one of the richest and best preserved Neogene mammal assemblages of the Iberian Peninsula. Generation of the mammal-bearing cavities started with the solution of underlying evaporites, which resulted in fissures that were subsequently enlarged by subsurface piping, a process rarely preserved in the ancient sedimentary record. The system of subterranean cavities evolved into a pseudokarst landscape, resulting in doline-like shafts reaching the ancient land surface. The sedimentary infilling of the cavities comprises both clastic and carbonate lithofacies that were investigated by outcrop observation, standard and scanning electron microscope petrography, mineralogical analysis, and stable isotope geochemistry. Gravel and breccia talus deposits, clast and mud-supported gravel, pebbly sandstone and mudstone are common detrital infill deposits mostly derived by overflow erosion of bedrock. The deposits containing the mammal bones are marls, and occur both in subsurface cavities and doline-like depressions. In the underground cavities, marlstone was mainly of clastic origin and accumulated in ponds scattered over the floor of the cavity. In contrast, marlstone deposits in the surface dolines formed mostly as a result of biochemical carbonate deposition in small shallow lakes subjected to fluctuation of the water level. The δ18O and δ13C carbonate values indicate different origins for the two kinds of marls. During the final phases of pipe infill the doline marlstone sealed the mammal sites, usually off-lapping the adjacent bedrock. [ABSTRACT FROM AUTHOR]

This article reports a detailed taphonomic study of the reference Miocene vertebrate site of Cerro de la Garita, (Concud, Teruel, Spain). The sedimentary record of the site indicates that it was a palaeo-lakeshore, and this conclusion is supported by aquatic environment-related taphonomic modifications of its fossils (both on their surfaces and internally). The site provided a water source that appears to have been regularly visited by herbivores. It was, therefore, also likely to have been a good feeding ground for predators and scavengers. Hyaena coprolites have been found at the site, and tooth marks were identified on some fossil bone surfaces. Bone fragments 2-5 cm in length showed clear evidence of heavy digestion and probable regurgitation. Abundant trampling marks were seen on the surface of many of the fossil bones, traits that are congruent with a damp lakeshore environment. Most of the remains were broken, and only a few anatomical elements belonging to the same individual were found close together, although never articulated (i.e. in a manner reflecting their anatomical connections). The fossils showed no signs of selection (either by shape or size) or abrasion, although a certain re-orientation suggests the influence of wave or strand line activity. Despite being an open-air site, none of the fossils appeared to be weathered, further suggesting that the surrounding environment was a damp lakeshore probably shaded by vegetation. Indeed, abundant signs of root activity were observed. No evidence of reworking, that is, post-burial disturbance or diachronic mixing of fossils, was seen, confirming the international value of Cerro de la Garita as a reference site for continental Miocene mammal assemblages. [ABSTRACT FROM AUTHOR]

The 18 ichnospecies of the vertically oriented, helical marine to marginal marine trace fossil Gyrolithes Saporta, 1884 known so far are revised. A new ichnospecies, G. lorcaensis isp. n. (Miocene, SE Spain), is introduced, and Conispiron Vialov, 1969 and Spirocircus Mikuláš and Pek, 1994 are included in Gyrolithes. The ichnotaxobases of the Gyrolithes ichnospecies are based on the character of the burrow margin (presence or absence of a wall or ornamentation) and/or on morphometric parameters (burrow width versus radius of the whorls). As a result of synonymization, 13 ichnospecies are recommended. The morphometric parameters of Gyrolithes show two distinct lineages (large ratio of whorl radius to burrow width and medium ratio of whorl radius to burrow width; 10-12 and 1-1.6, respectively). The third lineage (small ratio of whorl radius to burrow width; up to 1) is less distinct. [ABSTRACT FROM AUTHOR]

Abstract: Clavate borings found in the tympanic bulla of a Miocene cetacean from El Camp de Tarragona Basin constitute the first evidence of the ichnogenus Gastrochaenolites in bones of an autochthonous cetacean carcass. Previous records of similar trace fossils on marine bones were described from transported or reworked remains. Based on their morphology and ichnotaxonomy, the borings are assigned to the activity of pholadid bivalves, which would have colonized the skeletal carcass on the sea floor after removal of covering soft tissues. Sedimentological and paleontological data indicate a low-energy depositional setting with low sedimentation rate, which would have provided the temporal window for bivalve colonization. This new finding contributes to widen our knowledge of bioerosion in marine vertebrate skeletons. [Copyright &y& Elsevier]

Abstract: It is known from present-day climates that both temporal and spatial variations in precipitation can be more pronounced than those in temperature and thus influence ecosystems and human society in more substantial way. However, very little is known about such variations in the past. Here we present an analysis of 206 palaeoprecipitation data from two twelve million year long proxy records of precipitation for Southwest (Calatayud-Teruel basin) and Central Europe (Western and Central Paratethys), spanning the late Early and Middle to Late Miocene (17.8–5.3Ma) at a temporal resolution of about 80kyr and 200kyr, respectively. The estimates of precipitation are based on the ecophysiological structure of herpetological assemblages. The results show that precipitation variations in both regions have large amplitudes during the Miocene with comparable temporal trends at longer time scales. With locally 300mm up to more than 1000mm more rainfall per year than present, the early Langhian and the Tortonian were relatively wet periods, whereas the late Langhian and late Serravallian were relatively dry, with up to 300 to 500mm less precipitation than present. The most humid time intervals were the early and middle Tortonian washhouse climate periods. Overall, our data suggest that the latitudinal precipitation gradient in Europe from the Middle to Late Miocene were highly variable, with a general tendency towards a reduced gradient relative to present day values. The gradient decreases during cooling periods and increases during warming periods, similar to results from simulations of future climate change. Interestingly, the precipitation gradient was reversed during the second washhouse climate period and the Early Messinian, which may have causes a negative hydrologic balance in the Eastern Paratethys during the latter time. Yet, our reconstructed gradient curve shows no direct correlation with the global temperature signal from oxygen isotopes, which implies a non-linear regional response. Our results further suggest that major fluctuations in the precipitation gradient can be responsible for shifts in ecosystem distribution, and particularly, for faunal turnover in South Western Europe. [Copyright &y& Elsevier]

Abstract: A new Miocene shrew from east Central Spain is described. The new form, named Turiasorex pierremeini nov. gen., nov. sp., was found in 13-10–Ma old sediments of the Calatayud-Daroca and Teruel basins. It is characterized by an extreme dental morphology consisting of elements with low length-width ratios, implying a relatively short snout. Such an adaptation could point to a hypogeal life style – using burrows made by other mammals – with a non-standard shrew diet consisting not only of insects, but also of earthworms and possibly small vertebrates such as lizards. [Copyright &y& Elsevier]

Abstract: A new finding of a marine mammal is documented from the middle Miocene of El Camp basin in Tarragona (NE Spain). The incomplete and disarticulated bone remains belong to the skeleton of a juvenile cetacean. These remains appear deposited above a transgression surface and included within a glauconitic calcisiltite layer. This unit constitutes the beginning of a shallowing-upwards sequence and was deposited under low-energy conditions and low sedimentation rates in a middle-outer platform setting. This context was responsible for the long exposure of the remains and, consequently, an extension of the biostratinomic stage. These conditions favored the natural decomposition and disarticulation of the carcass, allowing the action of different types of scavenging organisms. The interpretation of the paleoenvironmental setting is based in the combination of different datasets: taphonomic data of the bone remains, paleoecologic and taphonomic information provided by the fauna associated to the bones, and ichnologic and sedimentologic interpretation of the sediments where the fossils are included. Combination of such different proxies enables a very good characterization of the paleoenvironmental context of the studied fossils. [Copyright &y& Elsevier]

Abstract: In an attempt to arrive at a preliminary reconstruction of the limnic food web of the Upper Miocene Bicorb Basin (Eastern Spain), and to obtain new palaeontological information regarding the salinity of its palaeolake, studies were made of the fossil assemblages of aquatic organisms in the outcrops of facies associations 2 and 3 (subunit b of the upper unit, established in 1998 by Anadón et al.) These outcrops (known as Venus, Cantera and Bicorb Insectos-1 and -3) are typical Konservat-Lagerstätten. We here describe four specimens of a new species of the cyprinodontid genus Aphanius (A. bicorbensis sp. nov.) plus several chironomid insects and coprolites, mainly from the Venus outcrop. Two morphotypes of chironomid pupal exuviae were found, both of which were attributed to the subfamily Chironominae. The larger morphotype was attributed to Chironomus sp. (tribe Chironomini) and the smaller to Tanytarsini gen. et sp. indet. Coprolites were separated into two types – C1 and C2 – based on their contents, i.e., the remains of chironomids or miliolid foraminifers respectively. The miliolid foraminifers belonged to the family Hauerinidae, possibly to the genus Quinqueloculina. It is concluded that Aphanius fish were second level consumers, feeding on chironomids and miliolid foraminifers. Primary producers were mainly represented by the aquatic plant Potamogeton, Botryococcus green algae, and microbial mats (almost certainly photosynthetic). This notably simple limnic food web and this aquatic fossil assemblage suggest that the Bicorb palaeolake was saline or brackish; the living taxa related to this assemblage are notably tolerant of high salinity. This salinity is related to the presence of a Triassic diapir on the southern side of the Bicorb Basin. In addition, non-bioturbated, finely laminated calcareous mudstones and exceptionally well-preserved delicate insects indicate the lake water to have shown a halocline (leading to meromictic episodes), with the development of microbial mats at the lake bottom. [Copyright &y& Elsevier]

Abstract: This study describes a new type of taphonomic alteration of fossil bone that occurred in a continental carbonate palaeolake environment at the reference Spanish Miocene site of Cerro de la Garita (Concud, Teruel). Scanning electron microscopy showed this type of alteration to be characterized by microtunnels that penetrate inward from the bone surface and by a branching-meandering arrangement of microchannels on the bone surface. These microtunnels had a highly electron dense inner wall, seen as a characteristic rim in transverse section. Microspheres were seen inside the microtunnels. Both this electron dense layer and these microspheres were found to be composed of calcium phosphate. These taphonomic modifications bear some similarities to, but also differs from, those caused by bacterial attack on bone and enamel in marine and terrestrial environments, suggesting the present process to be a new type of bioerosion. The microspheres inside the microtunnels were similar in size, shape and composition to the fossilized bacteria covering fossils from Fossil-Lagersttäten palaeolake sites, such as Libros (Teruel, Spain) and Messel (Germany). Under the transmission electron microscope these structures showed an apparent cell wall, suggesting them to be fossilized coccoid bacteria. [ABSTRACT FROM AUTHOR]

Abstract: Minor normal faults affecting Miocene conglomerates of the Barcelona Plain are constituted by a poorly developed fault core without a damage zone. Fault rocks are made of a red muddy material that has been obliterated by later diagenetic processes. The most important products are spherulites and palisades formed by orange bladed calcite crystals. These calcite crystals are interpreted as resulting from pedogenic processes, being similar to Microcodium. The precipitation of the calcite crystals was induced by evaporation together with biota activity. The presence of these pedogenic products has an important effect in fault evolution because: 1) they date fault evolution during the Miocene extension; 2) they indicate shallow burial depth and meteoric diagenetic environment during fault evolution; and, 3) they give the cohesiveness to the fault rock causing the sealing of the fault and its behaviour as a barrier to fluids. [Copyright &y& Elsevier]

Abstract: The Libros Gypsum is the thickest evaporite unit of the Miocene infill of the Teruel Basin in NE Spain. During the deposition of this unit, intense bacterial sulfate-reducing (BSR) activity in the lake depocenter generated a native sulfur deposit. Diagenetic gypsum resulted from subsequent sulfur oxidation. The different processes involved in these transformations were first investigated by Anadón et al. (1992). The present paper is concerned with this diagenetic gypsum from the stratigraphic, petrographic, isotopic and genetic points of view. Diagenetic gypsum occurs mainly as continuous or discontinuous layers, individual levels or lenses, irregular masses, nodules and micronodules, and veins. Its main textures are coarse-crystalline anhedral and fine-grained (alabastrine), both of which can replace any former lithology (carbonate, gypsum, and sulfur). The following sequence of processes and mineral/textural transformations is deduced: primary gypsum deposition — BSR and biodiagenetic carbonate/H2S production — growth of native sulfur — growth of diagenetic gypsum — partial recrystallization of the diagenetic gypsum textures. The gypsification of the native sulfur generated two types of banded structures in the diagenetic gypsum: (1) concentric structures of centripetal growth, and (2) expansive, roughly concentric structures. In the first type, the gypsification operated from the outer boundaries towards the inner parts. In the second type, part of the carbonate hosting the sulfur was also gypsified (replaced/cemented). In the diagenetic gypsum, the δ 34S values are in agreement with a native sulfur and H2S provenance. The δ 18Osulfate values, however, enable us to differentiate two main groups of values: one with positive values and the other with negative values. In the group of positive values, interstitial (evaporated) solutions participated in the sulfur oxidation; this process presumably occurred in a first oxidation stage during shallow-to-deeper burial of the Libros Gypsum unit. In the group of negative values, however, only meteoric waters participated in the oxidation, which presumably occurred in a second oxidation stage during the final exhumation of the unit. A third group of values is characterized by very high sulfur and oxygen values, suggesting that BSR residual solutions also participated in the oxidation processes locally. During the two oxidation stages, both the textural characteristics and the isotopic composition of the diagenetic gypsum indicate that gypsification operated as a multistadic process. [Copyright &y& Elsevier]

Abstract: High-resolution seismic data have been acquired in June 2008 on the Armorican Shelf (AS), in the northern Bay of Biscay, in order to reassess its stratigraphic architecture in detail and to study the impact of eustasy, tectonic and sediment delivery on the margin sedimentary record. Several profiles show fluvial-type incisions of several tens of meters (up to 54m) associated to a widespread erosion surface. Several hypotheses are proposed for the stratigraphic position of this surface and incisions. We suggest Middle to Late Miocene age. Considering the relatively quiescent tectonic activity of the margin, we infer that the relative sea-level fall responsible of aerial incision on the Miocene shelf is eustasy-related. We propose the attested Serravallian–Tortonian eustatic lowstand (c. 11.6Ma) as the key event responsible of such erosion and incision. This event marks the early beginning of the high-amplitude sea-level fluctuations that culminated during the Pleistocene and significantly controlled the present day AS morphology. The variability of vertical incision observed along single reaches can be explained by the confluence of several tributaries, the sinuosity of the channel and can be amplified by the unconsolidated nature of the Miocene substratum. The main pathways of the fluvial network corresponding to these buried valleys have been reconstructed and connections to other existing networks are proposed. [Copyright &y& Elsevier]

Abstract: It has been suggested that the Recent zoogeography and diversification of the killifish Aphanius is a result of the palaeogeographic reorganisation of the Mediterranean area during the Neogene. However, little is known about the fossil distribution of killifishes in the Mediterranean, and literature data are scattered. This paper summarizes the data on the stratigraphic range and palaeoecology of the Aphanius and Aphanolebias species from three time intervals in the Miocene of southwestern Europe, the Paratethys, and the Aegean based on previously described otoliths and articulated skeletons, and newly collected otoliths from Spain. Moreover, the mollusc palaeocommunities that co-occur with the otoliths from Spain are considered. Our data indicate that species-diversity and zoogeography of fossil killifishes is closely linked to those palaeogeographic and climate conditions that affect the abundance of brackish and swamp habitats. The appearance of fossil Aphanolebias or Aphanius in continental deposits of Early and Middle Miocene age can be considered indicative of a warm palaeoclimate with seasonal or interannual aridity. The relatively wide geographic distribution of the Late Miocene Aphanius crassicaudus is strikingly different from the zoogeographic pattern exhibited by the Early and Middle Miocene Aphanius species, and probably resulted from (i) increased numbers of brackish and swamp habitats due to the Messinian event, and (ii) the closure of the deep seaway between the former island of Italy and the mainland to the north. We hypothesize that the wide geographic distribution of the present-day A. fasciatus in the Mediterranean Sea, as well as the limited zoogeography of A. iberus and A. baeticus along the Spanish coast, is a result of zoogeographic history of their ancestors in the Late Miocene. Moreover, the present-day ability of Aphanius to survive under extreme conditions probably represents a vestige of the broad ecological tolerance of the Miocene Aphanius species. [Copyright &y& Elsevier]

Abstract: The North-Betic Strait, located in the Prebetic Zone (outermost part of the Betic Cordillera), was a narrow seaway connecting the Atlantic Ocean and the Mediterranean Sea through the Betic Cordillera during the Early Late Miocene. Strait facies consist of heterozoan bioclastic carbonates and mixed siliciclastics–carbonates. Local fan-delta deposits (conglomerates) also occur. The North-Betic Strait deposits exhibit huge trough cross-bedded structures. Single troughs are up to 5 m high and point to the east in easternmost outcrops. In central outcrops, they reach up to 15 m in height and some tens of metres in length and point both to the east and to the west. The westernmost outcrops show the largest cross-bedded structures, up to 20 m in height and some hundred of metres in length, all pointing to the west. The large-scale cross-bedding was generated by the migration of very large dunes moved by tides. The largest structures are inferred to have formed at depths of 90 m. Depth estimations indicate that the North-Betic Strait shallowed to the east and deepened to the west. The Miocene evolution towards the formation of the North-Betic Strait can be divided into a series of steps. The palaeogeography evolved from a south-facing platform, marginal to a northeastern relief, to a wide-open marine passage limited by a southern platform and, finally, to a tidal-dominated strait. The closing of the North-Betic Strait is recorded by the presence of lagoonal, silty sediments covered by a stromatolite layer and crowned by a red soil in the westernmost outcrops. [Copyright &y& Elsevier]

Abstract: Large burrow systems occur in the Miocene marine deposits of the Almería-Nijar Basin (Betic Cordillera, Southeast Spain). They consist of galleries of dense burrow segments, locally forming irregular networks. Cylindrical, branched (Y-shaped) structures, with diameters ranging from 8 to 22 cm and minimum lengths of 30–60 cm are abundant. In addition, galleries longer than 70–80 cm are common, and burrow segments larger than 200 cm are locally present. Burrows have smooth walls, without pellet reinforcements, but locally possible scratch marks are present. Burrow fill is structureless and has a similar composition to the host rock. These structures are assigned to the ichnogenus Thalassinoides Ehrenberg, displaying similarities with T. suevicus. Identification of the possible tracemaker is not straightforward, but decapod crustaceans, probably shrimp or shrimp-like organisms, are the most likely candidates. [Copyright &y& Elsevier]

The vertebrate community of the late Miocene locality of Batallones-1, Madrid Province, Spain, is mainly composed of mammals of the order Carnivora, which represents 98 per cent of the total number of macro-mammal fossils. Here, we describe craniodental remains of approximately 12 individuals of a new, highly specialized member of the Amphicyonidae, previously assigned to Amphicyon sp. cf. A. castellanus. A phylogenetic analysis of Amphicyoninae shows that this new form, named Magericyon anceps gen. et sp. nov., is markedly distinct from all other known Amphicyoninae, specifically in its hypercarnivorous features (strongly compressed upper canines, absence of dP1/dp1 and P2/p2, single-rooted p3, absence of a metaconid on the lower molars, and reduction of M2 relative to M1). [ABSTRACT FROM AUTHOR]

Bone marrow in ca. 10 Ma frogs and salamanders from the Miocene of Libros, Spain, represents the first fossilized example of this extremely decay-prone tissue. The bone marrow, preserved in three dimensions as an organic residue, retains the original texture and red and yellow color of hematopoietic and fatty marrow, respectively; moldic osteoclasts and vascular structures are also present. We attribute exceptional preservation of the fossilized bone marrow to cryptic preservation: the bones of the amphibians formed protective microenvironments, and inhibited microbial infiltration. Specimens in which bone marrow is preserved vary in their completeness and articulation and in the extent to which the body outline is preserved as a thin film of organically preserved bacteria. Cryptic preservation of these labile tissues is thus to a large extent independent of, and cannot be predicted by, the taphonomic history of the remainder of the specimen. [ABSTRACT FROM AUTHOR]

Abstract: Tectonic uplift and sea level lowering are two proposed mechanisms to explain the development of thresholds in front of the widespread evaporite basins of the circum-Mediterrranean region during the Miocene. Here we apply a multi-disciplinary approach to the continuously marine sequences of the Murcia–Cartagena basin to investigate which mechanism is responsible for the Tortonian evaporites of the Eastern Betics. First we develop a high-resolution chronology for the Venta de la Virgen section by integration of biostratigraphic, magnetostratigraphic and isotopic dating results. Next we construct palaeobathymetry and geohistory curves for this section and the Abad composite of the Sorbas basin. We show that the apparent differential vertical motions between the two sections cannot be explained by sea-level change but only by local tectonics. The Murcia–Cartagena basin shows significant tectonic uplift during the late Tortonian and early Messinian, while the neighboring Fortuna basin was rapidly subsiding. We conclude that tectonic activity on the Alhama de Murcia Fault was responsible for the emergence of a threshold that finally led to evaporite formation in the Fortuna basin. [Copyright &y& Elsevier]

The skull and cervical anatomy of the sabre-toothed felid Paramachairodus ogygia (Kaup, 1832) is described in this paper, with special attention paid to its functional morphology. Because of the scarcity of fossil remains, the anatomy of this felid has been very poorly known. However, the recently discovered Miocene carnivore trap of Batallones-1, near Madrid, Spain, has yielded almost complete skeletons of this animal, which is now one of the best known machairodontines. Consequently, the machairodont adaptations of this primitive sabre-toothed felid can be assessed for the first time. Some characters, such as the morphology of the mastoid area, reveal an intermediate state between that of felines and machairodontines, while others, such as the flattened upper canines and verticalized mandibular symphysis, show clear machairodont affinities. © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 144, 363−377. [ABSTRACT FROM AUTHOR]

This study investigates the controls on three-dimensional stratigraphic geometries and facies of shallow-water carbonate depositional sequences. A 15 km2 area of well-exposed Mid to Late Miocene carbonates on the margin of the Níjar Basin of SE Spain was mapped in detail. An attached carbonate platform and atoll developed from a steeply sloping basin margin over a basal topographic unconformity and an offshore dacite dome (Late Miocene). The older strata comprise prograding bioclastic (mollusc and coralline algae) dominated sediments and later MessinianPoritesreefs form prograding and downstepping geometries (falling stage systems tract). Seven depositional sequences, their systems tracts and facies have been mapped and dated (using Sr isotopes) to define their morphology, stratigraphic geometries, and palaeo-environments. A relative sea-level curve and isochore maps were constructed for the three Messinian depositional sequences that precede the late Messinian evaporative drawdown of the Mediterranean. The main 3D controls on these depositional sequences are interpreted as being: (i) local, tectonically driven relative sea-level changes; (ii) the morphology of the underlying sequence boundary; (iii) the type of carbonate producers [bioclastic coralline algal and mollusc-dominated sequences accumulated in lows and on slopes of< 14° whereas thePoritesreef-dominated sequence accumulated on steep slopes (up to 25°) and shallow-water highs]. Further controls were: (iv) the inherited palaeo-valleys and point-sourced clastics; (v) the amount of clastic sediments; and (vi) erosion during the following sequence boundary development. The stratigraphy is compared with that of adjacent Miocene basins in the western Mediterranean to differentiate local (tectonics, clastic supply, erosion history, carbonate-producing communities) versus regional (climatic, tectonic, palaeogeographic, sea-level) controls. [ABSTRACT FROM AUTHOR]

The age structures of two successive rodent communities are studied on the basis of a rich record from well-dated Miocene sections (17–10 Ma) in north-central Spain. Community age is defined as the mean of the residence times of the community members at the time of the locality age. Community ages are negatively correlated with the numbers of community members. These members are divided into residents (with continuous membership times ≥1.54 million years) and transients (with membership times <1.54 million years). During episodes of species loss, there is a preferential disappearance of transients while residents are retained, a pattern referred to as the ‘seniority rule.’ The residents define the studied communities. They are associated with early successional stages of vegetation, and transients are associated with later stages. Under stable conditions, early arrivals in succession are ‘transient’ and replaced by competitive later arrivals. The reversed roles of transients and residents in the studied fossil record are explained by assuming high degrees of disturbance. We view the system within the context of nonequilibrium metapopulation theory, in which competitively superior species become transients because of their dependence on ephemeral late successional habitats. [ABSTRACT FROM AUTHOR]

A fossil tracksite of Lower Miocene age discovered near Salinas de Añana, Alava (Spain), has rendered an exceptionally well-preserved assemblage of vertebrate ichnites. The site shows a high proportion of carnivore tracks (3 out of 5 mammal ichnospecies) and a high number of individual trackways (15), some including over 50 consecutive footprints. The carnivore ichnites are classified as Felipeda lynxi Panin & Avram, 1962, Felipeda parvula ichnosp. nov. and Canipeda longigriffa Panin & Avram, 1962, and they are attributed to a felid, an undetermined small aeluroid, and a herpestid, respectively. The long trackways allow determination of gaits, which include lateral sequence walks and diagonal sequence trots, and of speed, which ranges from 0.4 to 1.4 m/s. Froude numbers range between 0.1 and 0.8, agreeing with gait interpretations and speed calculations. The felid trackways provide the first known evidence of group traveling in fossil cats. The herpestid footprints show modern-grade adaptations for terrestrial locomotion and digging. [ABSTRACT FROM AUTHOR]

ABSTRACT The middle Miocene sedimentary fill of the Calatayud Basin in north-eastern Spain consists of proximal to distal alluvial fan-floodplain and shallow lacustrine deposits. Four main facies groups characteristic of different sedimentary environments are recognized: (1) proximal and medial alluvial fan facies that comprise clast-supported gravel and subordinate sandstone and mudstone, the latter exhibiting incipient pedogenic features; (2) distal alluvial fan facies, formed mainly of massive mudstone, carbonate-rich palaeosols and local carbonate pond deposits; (3) lake margin facies, which show two distinct lithofacies associations depending on their distribution relative to the alluvial fan system, i.e. front (lithofacies A), comprising massive siliciclastic mudstone and tabular carbonates, or lateral (lithofacies B) showing laminated and/or massive siliciclastic mudstone alternating with tabular and/or laminated carbonate beds; and (4) mudflat–shallow lake facies showing a remarkable cyclical alternation of green-grey and/or red siliciclastic mudstone units and white dolomitic carbonate beds. The cyclic mudflat–shallow lake succession, as exposed in the Orera composite section (OCS), is dominantly composed of small-scale mudstone–carbonate/dolomite cycles. The mudstone intervals of the sedimentary cycles are interpreted as a result of sedimentation from suspension by distal sheet floods, the deposits evolving either under subaerial exposure or water-saturated conditions, depending on their location on the lacustrine mudflat and on climate. The dolomite intervals accumulated during lake-level highstands with Mg-rich waters becoming increasingly concentrated. Lowstand to highstand lake-level changes indicated by the mudstone/dolomite units of the small-scale cycles reflect a climate control (from dry to wet conditions) on the sedimentation in the area. The spatial distribution of the different lithofacies implies that deposition of the small-scale cycles took place in a low-gradient, shallow lake basin located in an interfan zone. The development of the basin was constrained by gradual alluvial fan aggradation. Additional support for the palaeoenvironmental interpretation is derived from the isotopic compositions of carbonates from the various lithofacies that show a wide range of δ18 O and δ13 C values varying from -7·9 to 3·0‰ PDB and from -9·2 to -1·7‰ PDB respectively. More negative δ18 O and δ13 C values are from carbonate-rich palaeosols and lake-margin carbonates, which extended in front of the alluvial fan systems, whereas more positive values correspond to dolomite beds deposited in the shallow lacustrine environment. The results show a clear trend of δ18 O enrichment in the carbonates from lake margin to the centre of the shallow lake basin, thereby also demonstrating that the lake evolved under hydrologically closed conditions. [ABSTRACT FROM AUTHOR]

ABSTRACT A number of non-marine evaporite units composed of primary gypsum were deposited in saline lakes that developed in the southern Teruel Basin (NE Spain) during the Miocene. In the basin depocentre, a continuum of lacustrine evaporite lithofacies influenced by the activity of organisms is displayed. The Libros Gypsum was deposited in a deep lake, in which water stratification became unstable with progressive shoaling. Rhythmites, composed of laminae of pelletal gypsum and laminae of very fine lenticular gypsum crystals mixed with siliceous microorganisms, formed in addition to gypsum turbidites, intraformational gypsum breccias and slump structures. The pelletal laminae originated from the faecal activity of animals (crustaceans?) ingesting gypsum crystallites in the lake water during episodes of maximum evaporation, whereas the laminae of very fine lenticular gypsum mixed with microorganisms accumulated during episodes of relative dilution. In the wide marginal zones of the basin, the Libros Gypsum unit consists of massive to thin-bedded bioturbated gypsum and thin-bedded clotted gypsum, which formed in intermediate to very shallow (palustrine) water depths. The bioturbated gypsum lithofacies were produced by the action of diverse organisms, presumably worms and coleopterans, and chironomid larvae to a lesser extent; the massive lithofacies precipitated in very shallow water; and the thin-bedded lithofacies formed in shallow to deeper settings. The thin-bedded clotted gypsum is a relatively deep facies that may have diverse origins (e.g. bioturbation, compaction, disruption of soft sediments and early diagenesis). There is a well-developed metre-scale cyclicity in the marginal lake sequences, which is not observed in the inner lake deposits. This suggests a depth control in the various lacustrine subenvironments to record cyclic evaporitic processes. The isotopic composition of the gypsum indicates early sulphate-reducing bacterial activity in the bottom of the lake and suggests that the sulphate was derived from the chemical recycling of Triassic evaporites of the country rocks. [ABSTRACT FROM AUTHOR]

Abstract The Miocene sedimentary record of the Madrid Basin displays several examples of palaeokarstic surfaces sculpted within evaporite formations. One of these palaeokarstic surfaces represents the boundary between two main lithostratigraphic units, the Miocene Lower and Intermediate units of the Madrid Basin. The palaeokarst formed in lacustrine gypsum deposits of Aragonian age and corresponds to a surface palaeokarst (epikarst), further buried by terrigenous deposits of the overlying unit. Karst features are recognized up to 5·5 m beneath the gypsum surface. Exokarst and endokarst zones are distinguished by the spatial distribution of solution features, i.e. karren, dolines, pits, conduits and caves, and collapse breccias, sedimentary fills and alteration of the original gypsum across the karst profiles. The development of the gypsum palaeokarst began after drying out of a saline lake basin, as supported by recognition of root tubes, later converted to cylindrical and funnel-shaped pits, at the top of the karstic profiles. The existence of a shallow water table along with low hydraulic gradients was the main factor controlling the karst evolution, and explains the limited depth reached by both exokarst and endokarst features. Synsedimentary fill of the karst system by roughly laminated to massive clay mudstone with subordinate carbonate and clastic gypsum reflects a punctuated sedimentation regime probably related to episodic heavy rainfalls typical of arid to semi-arid climates. Duration of karstification is of the order of several thousands of years, which is consistent with previous statements that gypsum karstification can develop rapidly over geologically short time periods. [ABSTRACT FROM AUTHOR]

This paper concerns the evaporite units, depositional systems, cyclicity, diagenetic products and anhydritization patterns of the Calatayud Basin (non-marine, Miocene, central Spain). In outcrop, the sulphate minerals of these shallow lacustrine evaporites consist of primary and secondary gypsum, the latter originating from the replacement of anhydrite and glauberite. In the evaporative systems of this basin, gypsiferous marshes of low salinity can be distinguished from central, saline lakes of higher salinity. In the gypsiferous marsh facies, the dominant, massive, bioturbated gypsum was partly replaced by synsedimentary chert nodules and siliceous crusts. In the saline lake facies, either cycles of gypsiferous lutite-laminated gypsarenite or irregular alternations of laminated gypsum, nodular and banded glauberite, thenardite and nodular anhydrite precipitated. Early replacement of part of the glauberite by anhydrite also occurred. Episodes of subaerial exposure are represented by: (1) pedogenic carbonates (with nodular magnesite) and gypsiferous crusts composed of poikilitic crystals; and (2) nodular anhydrite, which formed in a sabkha. Additionally, meganodular anhydrite occurs, which presumably precipitated from ascending, highly saline solutions. The timing of anhydritization was mainly controlled by the salinity of the pore solutions, and occurred from the onset of deposition to moderate burial. Locally, a thick (>200 m) sequence of gypsum cycles developed, which was probably controlled by climatic variation. A trend of upward-decreasing salinity is deduced from the base to the top of the evaporite succession. [ABSTRACT FROM AUTHOR]

The Las Minas Gypsum Unit consists of more than 100 m of alternations of gypsum, carbonates and marls in Las Minas Basin (Betic Cordillera). Although this unit has been previously described as lacustrine, a marine influence in the basin has been suggested. This study provides new geochemical and paleontological data supporting the marine influence during the interevaporitic episodes, allowing to refine the palaeogeography of the eastern Betic Seaway during the Late Tortonian.87Sr/86Sr ratios in gypsum (0.70797 to 0.70825) suggest recycling of Triassic evaporites. The sulphate isotopic values in gypsum (11.5 < δ34S VCDT < 21.9‰; 16.6 < δ18O VSMOW < 28.1‰) are indicative of microbial sulfate-reduction activity. Carbonates are mainly composed of dolomite formed by subspherical crystal aggregates related to bio-mediated processes. The 87Sr/86Sr values in the interevaporitic carbonates (0.70823 to 0.70851) are higher than those expected for Triassic marine authigenic carbonates but lower than expected for the Late Miocene ones, suggesting a mixing of continental and marine water contributions. The 'non-marine' isotopic values in gypsum and carbonates contrast with an abundant content of marine siliceous fossils (radiolarians, diatoms, porifera, etc.) in the marls and carbonates that reveals marine incursions into the basin between periods of gypsum precipitation. A tephra layer identified in Las Minas and in the nearby El Cenajo Basin, located in a more inland position, allows a precise correlation between both basins, showing marine fossils in Las Minas and lacustrine in El Cenajo. In El Cenajo Basin, marine microfossils have been found but only in some levels, while others show lacustrine diatoms. A new palaeogeographic model of evaporitic lakes with temporal marine connections is proposed for the latest Tortonian in this region, when the uplift of the Betic Cordillera was very active accelerating the palaeogeographic evolution. • Interevaporitic materials in Las Minas show a diverse marine association. • Bacterially induced dolomite is abundant in the Evaporitic Unit. • A datum has been stablished between Las Minas and Cenajo basins. • New palaeogeographic reconstruction is proposed for the study area. • New geochemical data demonstrate marine incursions in Las Minas. [ABSTRACT FROM AUTHOR]

Palaeoichnology is known to be a powerful tool for the characterisation of unconformity surfaces. In a Neogene post-orogenic basin of the Betic domain (Alicante, SE Spain), a complex Miocene transgressive event on an exposed Eocene succession is recorded. The resulting unconformity surface as well as the overlying beds resulting from the establishment of a nearshore environment are ichnologically and palaeoecologically analysed. Different boring structures related to the Entobia ichnofacies were observed on a variety of substrates, including i) the rocky Eocene substrate, ii) Tortonian conglomerates and breccias, iii) oyster and coral patches (mainly represented by Tarbellastraea). Boring structures are mainly represented by Gastrochaenolites , Entobia and, more rarely, Trypanites and Spirolites ? Different colonization patterns were identified, including truncated Gastrochaenolites and Entobia that are extensively developed on the Eocene rockground, small-sized Entobia , and superficial bioerosion on conglomerates and breccias, and Gastrochaenolites hospitium on corals; a selective colonization of G. hospitium was observed, with Tarbellastraea much more intensively bioeroded than Porites. Finally, the integration of stratigraphic, palaeoecological and ichnological data allowed for the identification of three different phases in the Miocene transgression: i) slow transgression with the consequent colonization of the Eocene rockground, the production of a wide planar surface and the truncated Gastrochaenolites - Entobia assemblage; ii) the breaking of this uniform coastal setting into areas characterized by different hydrodynamics, with coral development where turbulence was higher; this second phase was of limited temporal extension, with a limited accommodation space; iii) a final phase characterized by a new transgressive pulse leading to the establishment firstly of a restricted inner platform and secondarily of a slightly deeper sandy platform; in this phase, bioerosion was limited to shells, while soft- and loose-ground burrows as Ophiomorpha developed within the substrate. • Bioerosive pattern on an unconformity surface unravel a Miocene transgressive event. • Ichnological/palaeoecological approaches increase the fidelity of transgressive phases. • Gastrochaenolites and Entobia are the most common ichnogenera. • Boring bivalves and coral colonies show mutual and symbiotic interaction. • Three phases are recorded from first colonization to establishment of an open platform. [ABSTRACT FROM AUTHOR]

Nursery areas are fundamental for the success of many marine species, particularly for large, slow-growing taxa with low fecundity and high age of maturity. Here, we examine the population size-class structure of the extinct gigantic shark Otodus megalodon in a newly described middle Miocene locality from Northeastern Spain, as well as in eight previously known formations (Temblor, Calvert, Pisco, Gatún, Chucunaque, Bahía Inglesa, Yorktown and Bone Valley). In all cases, body lengths of all individuals were inferred from dental parameters and the size-class structure was estimated from kernel probability density functions and Gaussian mixture models. Our analyses support the presence of five potential nurseries ranging from the Langhian (middle Miocene) to the Zanclean (Pliocene), with higher densities of individuals with estimated body lengths within the typical range of neonates and young juveniles. These results reveal, for the first time, that nursery areas were commonly used by O. megalodon over large temporal and spatial scales, reducing early mortality and playing a key role in maintaining viable adult populations. Ultimately, the presumed reliance of O. megalodon on the presence of suitable nursery grounds might have also been determinant in the demise of this iconic top predatory shark.

The exceptional fossil sites of Cerro de los Batallones (Madrid Basin, Spain) contain abundant remains of Late Miocene mammals. From these fossil assemblages, we have inferred diet, resource partitioning and habitat of three sympatric carnivorous mammals based on stable isotopes. The carnivorans include three apex predators: two sabre-toothed cats (Felidae) and a bear dog (Amphicyonidae). Herbivore and carnivore carbon isotope (δ13C) values from tooth enamel imply the presence of a woodland ecosystem dominated by C3 plants. δ13C values and mixing-model analyses suggest that the two sabre-toothed cats, one the size of a leopard and the other the size of a tiger, consumed herbivores with similar δ13C values from a more wooded portion of the ecosystem. The two sabre-toothed cats probably hunted prey of different body sizes, and the smaller species could have used tree cover to avoid encounters with the larger felid. For the bear dog, δ13C values are higher and differ significantly from those of the sabre-toothed cats, suggesting a diet that includes prey from more open woodland. Coexistence of the sabre-toothed cats and the bear dog was likely facilitated by prey capture in different portions of the habitat. This study demonstrates the utility of stable isotope analysis for investigating the behaviour and ecology of members of past carnivoran guilds. [ABSTRACT FROM AUTHOR]