Laura Piñuela

Museo del Jurasico de Asturias (MUJA)

The Principality of Asturias (or simply Asturias) is a region located in the North of Spain (SW of Europe) limited by the Cantabrian Sea in the North and the Castilla y León, Cantabria and Galicia regions in the South, East and West respectively. The Asturias Coast represents around 30% of the Cantabrian Coast, the northern limit of the Iberian Peninsula, and is surrounded by the Cantabrian Sea. This sea represents the transition of the Atlantic Ocean to the Biscay Gulf, between Spain and France. Towards the South, the Cantabrian Coast is limited by the Cantabrian Mountains, up to 2,648 m altitude, which axis is located only at 20–50 km from the sea.

Ongoing studies of a multiple track-bearing horizons from massive excavations in the Jinju Formation (Lower Cretaceous) of South Korea have yielded a remarkable diversity of avian, nonavian dinosaur, pterosaur, crocodilian and mammal tracks, many very small and well preserved. Here we report diminutive, didactyl tracks (~1.0 cm long) assigned to a new dromaeosaurid ichnogenus Dromaeosauriformipes, which resembles the larger, but still quite small, ichnogenus Dromaeosauripus, also from the same formation only 30 km away. These diminutive tracks are consistent with the foot size of smaller dromaeosaurid taxa like Early Cretaceous Microraptor from China, and may represent diminutive species or juveniles of larger species. The association of tracks with lakeshore sediments is consistent with the evidence that Microraptor was a fish eater. Two trackways and isolated tracks indicate variable trackmaker gaits and speeds. If oviparous, as assumed for most non-avian dinosaur neonates, the trackmakers must have hatched from tiny eggs. Previous studies of the Korean Cretaceous indicate the presence of other diminutive (~1.0 cm long) theropod tracks (Minisauripus). Such occurrences strongly suggest that small tracks attributed to juveniles, or very small tetrapod species, are more common than previously supposed especially where suitable preservation conditions prevailed.

The Kimmeridgian Vega, Tereñes and Lastres formations of Asturias have yielded a rich vertebrate fauna, represented by both abundant tracks and osteological remains. However, skeletal remains of theropod dinosaurs are rare, and the diversity of theropod tracks has only partially been documented in the literature. Here we describe the only non-dental osteological theropod remain recovered so far, an isolated anterior caudal vertebra, as well as the largest theropod tracks found. The caudal vertebra can be shown to represent a megalosaurine megalosaurid and represents the largest theropod skeletal remain described from Europe so far. The tracks are also amongst the largest theropod footprints reported from any setting and can be assigned to two different morphotypes, one being characterized by its robustness and a weak mesaxony, and the other characterized by a strong mesaxony, representing a more gracile trackmaker. We discuss the recently proposed distinction between robust and gracile large to giant theropod tracks and their possible trackmakers during the Late Jurassic-Berriasian. In the absence of complete pedal skeletons of most basal tetanurans, the identity of the maker of Jurassic giant theropod tracks is difficult to establish. However, the notable robustness of megalosaurine megalosaurids fits well with the described robust morphotypes, whereas more slender large theropod tracks might have been made by a variety of basal tetanurans, including allosaurids, metriocanthosaurids or afrovenatorine megalosaurids, or even exceptionally large ceratosaurs. Concerning osteological remains of large theropods from the Late Jurassic of Europe, megalosaurids seem to be more abundant than previously recognized and occur in basically all Jurassic deposits where theropod remains have been found, whereas allosauroids seem to be represented by allosaurids in Western Europe and metriacanthosaurids in more eastern areas. Short-term fluctuations in sea level might have allowed exchange of large theropods between the islands that constituted Europe during the Late Jurassic.

The MUJA (Museo del Jurásico de Asturias, Jurassic Museum of Asturias) has an interesting collection of theropod tracks that show similarities with the ichnogenera assigned to the Eubrontes-Grallator plexus. In this paper we describe in detail the morphology of 21 specimens recovered from different localities on “The Dinosaur Coast” of Asturias, plus four specimens preserved in outcrops in the sea cliffs of Les Vinaes (Villaviciosa). All the specimens are from the outcrops of the Lastres Formation, which is Kimmeridgian in age. The general morphology of the tracks, the footprint length-width ratio, the mesaxony, low divarication of the digits (II-IV) and the absence of hallux and metatarsophalangeal impressions suggest that the tracks are more similar to Grallator than to any other theropod ichnotaxa. Geometric morphometric analysis (principal component analysis, PCA) based on 2D landmark techniques suggests that they differ from Kalohipus bretunensis (as yet the only Grallator-like ichnotaxon described in the Iberian Peninsula) mainly in the divarication angles and in the projection of digit III.

In the last three decades vertebrate ichnology went through a renaissance due the discovery of new tracksites and the application of rigorous analytic methods (e.g., synapomorphy analyses). This finally allowed full hypothesis testing and a better integration of vertebrate ichnology in paleobiologic, paleoecologic and paleobiogeographic studies. In this chapter we provide a review of recent advances in vertebrate ichnology, focusing on Mesozoic terrestrial reptiles. By documenting evolutionary patterns, especially regarding locomotor mechanics and behavior, the track record provides clues often undocumented by the skeletal record. Given the abundance and distribution of tracks, the ichnologic record can also be particularly informative when considering timing of appearance of clades, even if only at high taxonomic levels. Ichnologic studies are, however, affected by several biases, such as unequal probability of preservation in different depositional environments, preservational factors, limb–substrate interactions, and convergence in autopodia morphology. In order to contribute to a better understanding of the evolutionary history of life, and its interplay with the changing Earth, ichnologic data need to be integrated with the body fossil record in order to provide a “total-evidence” approach. Only this way can palaeichnology be integrated in evolutionary biology and contribute to macroevolutionary studies finally taking place at the “high table” of paleobiology.

At least four parallel trackways of medium-sized and robust ornithopods are described from the Upper Jurassic Tereñes tracksite in Asturias (N. Spain). While the tracks and trackways of small and gracile ornithopods are common in the Jurassic record, large ornithopods are very rare in this period. Ornithopod gregarious behavior has been recorded from many Cretaceous ichnoassemblages, but there are few examples from the Jurassic, and these always relate to small individuals. The Asturian tracks are quite different from known ichnogenera, but they are not sufficiently well preserved to propose a new one. Medium-large Jurassic ornithopods with robust feet such as Draconyx or Cumnoria are the best candidates to be the trackmakers.

RESUMEN 3Dpaleo.net es una plataforma web en fase de desarrollo que muestra modelos tridimensionales hiperrealistas y en alta definición de algunos de fósiles más emblemáticos del Museo de Ciencias Naturales de la Universidad de Zaragoza y del Museo del Jurásico de Asturias (MUJA), colaboradores de la primera fase del proyecto. Se trata de una iniciativa promovida por la empresa Paleoymás con el fin de explorar y explotar las posibilidades de las nuevas tecnologías, aplicándolas a la divulgación de la paleontología y a la mejora de técnicas expositivas y de difusión del conocimiento. 3Dpaleo.net facilita, a través de internet, la visualización de los fósiles y de algunos de sus detalles más interesantes. Palabras clave: Divulgación paleontológica, nuevas tecnologías, TICs, digitalización de fósiles, innovación museográfica. ABSTRACT 3Dpaleo.net is a website, under development, that shows high definition hyperrealistic 3D models of some emblematic fossils of the museums that have collaborated in this first stage of the project: The Natural Sciences Museum of the University of Zaragoza and the Jurassic Museum of Asturias (MUJA). It is promoted by Paleoymás with the aim of exploring and developing the possibilities of new technologies, applying them to the popularization of paleontology and the improvement of both; expositive technics and knowledge sharing. 3Dpaleo.net helps through the internet to display fossils and some of their most interesting details.

We constructed a geological map, a 3D model and cross-sections, carried out a structural analysis, determined the stress fields and tectonic transport vectors, restored a cross section and performed a subsidence analysis to unravel the kinematic evolution of the NE emerged portion of the Asturian Basin (NW Iberian Peninsula), where Jurassic rocks crop out. The major folds run NW-SE, normal faults exhibit three dominant orientations: NW-SE, NE-SW and E-W, and thrusts display E-W strikes. After Upper Triassic-Lower Jurassic thermal subsidence, Middle Jurassic doming occurred, accompanied by normal faulting, high heat flow and basin uplift, followed by Upper Jurassic high-rate basin subsidence. Another extensional event, possibly during Late Jurassic-Early Cretaceous, caused an increment in the normal faults displacement. A contractional event, probably of Cenozoic age, led to selective and irregularly distributed buttressing and fault reactivation as reverse or strike-slip faults, and folding and/or offset of some previous faults by new generation folds and thrusts. The Middle Jurassic event could be a precursor of the Bay of Biscay and North Atlantic opening that occurred from Late Jurassic to Early Cretaceous, whereas the Cenozoic event would be responsible for the Pyrenean and Cantabrian ranges and the partial closure of the Bay of Biscay.

This study focuses on new records of freshwater bivalves from the Late Jurassic Vega, Tereñes and Lastres formations of Asturias, northern Spain. Five new taxa Mujanaia abeuensis gen. et sp. nov., 'Unio' asturianus sp. nov., Margaritifera? lagriega sp. nov., Asturianaia colunghensis gen. et sp. nov. and Asturianaia lastrensis gen. et sp. nov. are described and included in the families Unionidae and Margaritiferidae (Unionida); they are compared and contrasted with other European, Asiatic and North American species. Their discovery constitutes the oldest records of Unionida in Spain, and they provide new palaeogeographical data on the distribution and origin of this group in Europe. These taxa are also an effective tool for the environmental reconstruction of the Jurassic ecosystems of Spain's Dinosaur Coast.

Stacked specimens of Rosselia socialis from the Middle to Upper Ordovician Castro Formation of Asturias, northern Spain represent an example of an infaunal community able to move upwards simultaneously to avoid burial due to sedimentation from unidirectional currents. This ichnofabric is similar to those described from younger deposits and attributed to equilibrium structures produced by polychaetes belonging to the Order Terebellida. Although high density of specimens has been documented in Cambrian Rosselia suites, the Ordovician occurrence from Asturias is so far the oldest example of a Rosselia ichnofabric recording synchronous equilibrium behaviour of a whole community. Despite uncertainties derived from their patchy fossil record and potential for behavioral convergence, trace-fossil evidence seems to indicate that some groups of polychaetes were efficient burrowers since the early Cambrian. Rosselia ichnofabrics reflect an increased complexity of the trophic web and the ability of infaunal polychaete communities to colonize sandy, relatively high-energy settings by the early Paleozoic.

Ichnological analysis of deep-sea trace fossil assemblages from the Cenozoic turbiditic succession of the Campo de Gibraltar Complex (Cádiz Province, southern Spain) is presented. A relatively diverse and abundant trace fossil assemblage is recognized, with 20 ichnogenera belonging to the nongraphoglyptid assemblage and 12 to the graphoglyptid assemblage. Nongraphoglyptid traces are dominated by Chondrites, Halopoa, Helminthopsis, Lophoctenium, Nereites, Ophiomorpha, Phycosiphon, Planolites, Scolicia, Thalassinoides and Zoophycos, while Gordia and Tubotomaculum are common, and Cladichnus, Gyrophyllites, Polykampton, Rotundusichnium, Rutichnus, Spirophycus and Stelloglyphus are scarce or rare. Except for Helminthopsis and Spirophycus, all ichnotaxa are post-depositional structures, with feeding forms (pacichnia and fodinichnia) dominant. The graphoglyptid assemblage consists of agrichnia, predepositional trace fossils, with abundant Desmograpton, and Paleodictyon; in turn, Helminthorhaphe, Megagrapton and Urohelminthoida are common, and the rest, including Belorhaphe, Cosmorhaphe, Glockerichnus, Helicolithus, Lorenzinia, Paleomeandron and Spirorhaphe, are scarce or rare. Trace fossil assemblages can be attributed to the Nereites ichnofacies, with dominance of the Nereites ichnosubfacies, but the Ophiomorpha rudis ichnosubfacies and the Paleodictyon ichnosubfacies could be associated to different depositional settings into the deep-marine basin-floor and the deep-sea fan. Together with the tectonic activity and climate, variations in the petrology of the source area, inducing differences in clay mineral composition, may influence the input and deposition of organic matter, affecting graphoglyptid composition. The graphoglyptid assemblage is dominated by winding and meandering structures, some branched, as well as networks; while radial structures and spiral structures are scarce and little diversified. The studied successions are of special interest for interpreting paleoenvironmental and evolutionary changes affecting graphoglyptid assemblages from Paleocene to Miocene in the Campo de Gibraltar Complex.

The Vega Formation (Upper Jurassic, Asturias, Spain) contains two Kimmeridgian outcrops – the Abeu and Huerres sections – with bivalves coated with carbonate microbialites (oncoids). The bivalve shells in the Abeu section were replaced early by calcite, while those of the Huerres section were dissolved and the moulds filled by late diagenetic cements. For the Abeu shells, there was a loss of Sr and a gain of Mg, Fe and Mn during the replacement process, but much of the original organic matter was retained. Part of the S present can be linked to this organic matter, and part to the sulphate that replaced the carbonate groups in the calcite. The thin microbialites inside the shells of some of the Huerres bivalves have allowed us to estimate the influence of the growth rate on the incorporation of trace elements in calcite. With an approximately six times lower growth rate, the internal microbialite incorporates less Mg and S and more Fe and Mn than the external one, while maintaining the Sr content. The trace element content (Mg, S, Sr, Fe and Mn) of the Huerres and Abeu microbialites are similar; these coatings may therefore have been formed in the same type of freshwater but in different microenvironments. Given the substantial sulphate content of the microbialites from both sections, this freshwater probably came from hot springs. However, the high Fe/Mn ratio of the Abeu microbialites suggests a reducing environment during their formation. Indeed, δ18O and δ13C data confirm that the Abeu and Huerres microbialites were formed in different microenvironments: the positive covariance for δ18O and δ13C of the Abeu microbialites and replaced shells (r2 = 0.83) and the wide range of variation for δ18O (2.80‰) together suggest that the microbialite crusts grew in isolated ponds where evaporation was dominant. In the Huerres microbialites the positive covariance for δ18O and δ13C (r2 = 0.59) and the narrow range of variation for δ18O (0.74‰) indicate that the Huerres section was formed in a more open environmental system where degassing predominated over evaporation.

The historically-famous Lotus Fortress site, a deep 1.5-3.0-meter-high, 200-meter-long horizonal notch high up in near-vertical sandstone cliffs comprising the Cretaceous Jiaguan Formation, has been known since the 13th Century as an impregnable defensive position. The site is also extraordinary for having multiple tetrapod track-bearing levels, of which the lower two form the floor of part of the notch, and yield very well preserved asseamblages of ornithopod, bird (avian theropod) and pterosaur tracks. Trackway counts indicate that ornithopods dominate (69%) accounting for at least 165 trackmakers, followed by bird (18%), sauropod (10%), and pterosaur (3%). Previous studies designated Lotus Fortress as the type locality of Caririchnium lotus and Wupus agilis both of which are recognized here as valid ichnotaxa. On the basis of multiple parallel trackways both are interpreted as representing the trackways of gregarious species. C. lotus is redescribed here in detail and interpreted to indicate two age cohorts representing subadults that were sometimes bipedal and larger quadrupedal adults. Two other previously described dinosaurian ichnospecies, are here reinterpreted as underprints and considered nomina dubia. Like a growing number of significant tetrapod tracksites in China the Lotus Fortress site reveals new information about the composition of tetrapod faunas from formations in which the skeletal record is sparse. In particular, the site shows the relatively high abundance of Caririchium in a region where saurischian ichnofaunas are often dominant. It is also the only site known to have yielded Wupus agilis. In combination with information from other tracksites from the Jiaguan formation and other Cretaceous formations in the region, the track record is proving increasingly impotant as a major source of information on the vertebrate faunas of the region. The Lotus Fortress site has been developed as a spectacular, geologically-, paleontologically- and a culturally-significant destination within Qijiang National Geological Park.

We study the NE emerged portion of the Asturian Basin, a Permian-Mesozoic extensional basin (NW Iberia) partially inverted during the Cenozoic as a result of a contractional event. A geological map, a 3D model, cross sections, a structural analysis and a 3D photogrammetric study were performed. Our goal is to comprehend the relevance, relative timing and behaviour of the extensional and contractional structures formed during the tectonic events defining its current framework. A Mesozoic extensional episode characterized by fault activity, increase of thermal flow and uplift and a Cenozoic contractional episode responsible for reverse and strike-slip reactivation of old faults and generation of few thrusts and folds occurred. The information obtained here should assist with the study of worse exposed inland parts of the basin and the seismic interpretation of offshore data. Additionally, understanding the structural configuration of the Jurassic rocks cropping out in the zone might be of interest as an analogue for hydrocarbon industry, given that some of them may be potential hydrocarbon source rocks. Additionally, unravelling their structure is essential considering the recent request for a hydrocarbon exploration permit by an oil company including this area which, in turn, belongs to a state reserve acreage for CO2 storage.

Trace fossils provide the only records of Early Cretaceous birds from many parts of the world. The identification of traces from large avian track-makers is made difficult given their overall similarity in size and tridactyly in comparison with traces of small non-avian theropods. Reanalysis of Wupus agilis from the Early Cretaceous (Aptian-Albian) Jiaguan Formation, one of a small but growing number of known avian-pterosaur track assemblages, of southeast China determines that these are the traces of a large avian track-maker, analogous to extant herons. Wupus, originally identified as the trace of a small non-avian theropod track-maker, is therefore similar in both footprint and trackway characteristics to the Early Cretaceous (Albian) large avian trace Limiavipes curriei from western Canada, and Wupus is reassigned to the ichnofamily Limiavipedidae. The reanalysis of Wupus reveals that it and Limiavipes are distinct from similar traces of small to medium-sized non-avian theropods (Irenichnites, Columbosauripus, Magnoavipes) based on their relatively large footprint length to pace length ratio and higher mean footprint splay, and that Wupus shares enough characters with Limiavipes to be reassigned to the ichnofamily Limiavipedidae. The ability to discern traces of large avians from those of small non-avian theropods provides more data on the diversity of Early Cretaceous birds. This analysis reveals that, despite the current lack of body fossils, large wading birds were globally distributed in both Laurasia and Gondwana during the Early Cretaceous.

The Yangouxia dinosaur tracksites are well known for a diverse assemblage of tetrapod tracks preserved as natural impressions (concave epireliefs) on large bedding planes, representing a locally widespread surface marking the transition from a sand- to a mud-dominated sequence in the Hekou Group. Previous ichnological studies at these large sites have focused on the morphology and ichnotaxonomy of the tracks, including a single trackway representing the first pterosaur tracks reported from China. Here, we report a distinctly different assemblage associated with minor sandstones in the mud-dominated sequence 20 m above the main tracksite level. This assemblage consists of at least 20 pterosaur manus track casts attributed to a single ichnotaxon (Pteraichnus). No pes tracks have been identified. These tracks mostly occur in random orientations, although one possible trackway segment is inferred, to represent walking progression. Manus-only pterosaur track assemblages are common and likely reflect differential registration depths of manus and pes and/or sub optimal preservation conditions. The tracks are associated with distinctive invertebrate traces including Cochlichnus, Spongeliomorpha and Paleophycus and suggest the pterosaurs were likely feeding on the invertebrate tracemakers.

This work provides new insights to assess the factors controlling carbonate deposition in the siliciclastic fluvial systems of rift basins. Sedimentological and stable-isotope data of microbialites and associated carbonate facies, along with regional geological information, are shown to reveal the influence of climate and tectonics on the occurrence and attributes of carbonate deposits in these settings. The Vega Formation — a 150 m thick Lower Kimmeridgian siliciclastic fluvial sequence in northern Spain — constitutes a candidate for this approach. This unit includes varied facies (stromatolites; rudstones, packstones and wackestones containing oncoids, intraclasts, charophytes and shell bioclasts; marlstones and polygenic calcareous conglomerates) that formed in a low-gradient fluvial–lacustrine system consisting of shallow, low-sinuosity oncoid-bearing channels and pools within marshy areas, with sporadic coarse alluvial deposition. The sedimentological attributes indicate common erosion by channel overflow and rapid lateral changes of subenvironments caused by water-discharge variations. The carbonate fluvial–lacustrine system developed near uplifted marine Jurassic rocks. The occurrence of the system was conditioned by normal faults (active during the deposition of the unit) that favoured: (i) springs of HCO3–Ca-rich water from a Rhaetian–Sinemurian carbonate-hosted aquifer; and (ii) carbonate deposition in areas partially isolated from the adjacent siliciclastic fluvial system. The microbialite δ13C and δ18O values support deposition in a hydrologically open system, fed by ambient-temperature meteoric water, with riparian vegetation. Three types of lamination in the stromatolites and oncoids reflect distinct morphological types of cyanobacterial communities. The textural pattern of lamination parallels δ13C and δ18O changes, suggesting short-term cycles of precipitation and temperature. A moderately to strongly contrasted seasonal and/or pluriannual precipitation regime is inferred from the cyclic δ13C pattern of the lamination and from the discontinuous and asymmetrical growth of oncoids. Thus, the isotopic and sedimentological attributes of the carbonate deposits are linked to short-term climate changes associated with semi-arid conditions, consistent with the studied climatic zone.This article is protected by copyright. All rights reserved.

The trace-fossil name Tubotomaculum has been extensively used to refer to spindle-shaped pellet-filled tubes present in Upper Cretaceous to Miocene deep-marine deposits of the western Mediterranean region. However, it has never been formally diagnosed, and accordingly it was regarded as a nomen nudum. In this paper, we formally introduce the ichnogenus Tubotomaculum, including the new ichnospecies Tubotomaculum mediterranensis. Bioglyphs, represented by scratch traces that may be present on the basal and lateral surfaces of the structure, suggesting production by crustaceans. The functional meaning of these structures challenges the simple model of a mining strategy. Instead, the storing of pellets to use them as a bacteria-enriched resource during times when organic detritus was scarce is suggested. The association with chemoautothrophic bacteria in modern analogs of Tubotomaculum provides a crucial piece of evidence to support the cache model. Integration of information from modern environments and the fossil record points to a connection between Tubotomaculum, mud volcanism, fluid venting, and hydrocarbon seeps. The presence of bioglyphs suggests firmgrounds that may have resulted from bottom current scouring of the sea sediment, leading to erosional exhumation of previously buried compacted sediment, which was therefore available for colonization by the infauna. However, an alternative scenario involves enriched fluids related to mud-volcanism resulting in reducing conditions that favored carbonate precipitation and nodule formation just a few centimeters below the sediment-water interface.

Deposit-feeding strategies recorded in the ichnogenus Phymatoderma from the Lower Jurassic shelf-sea deposits in central (Dotternhausen, southwest Germany) and western Europe (Asturias, north Spain) are revealed by geochemical and microscopic analyses. Thin-section observations showed that the trace-maker of Phymatoderma from Asturias ingested bioclastic skeletal sediments, and that from Dotternhausen ingested fine-grained siliciclastic sediments. Geochemical analysis elucidated that the trace-makers of Phymatoderma from both Asturias and Dotternhausen were non-selective deposit feeders (i.e., indiscriminately ingesting sediment particles on the seafloor), although the ingested sediments were significantly different in lithology. Microscopic analysis revealed that the early Jurassic Phymatoderma-producers mainly fed on calcareous nannoplankton, i.e., coccolithophores, dinoflangellates, as well as their phytodetritus. Here, we demonstrate a substrate-independent feeding mode in the early Jurassic Phymatoderma-producers, which accords with the similar morphologic, paleogeographic, and chronologic context of Phymatoderma from Asturias and Dotternhausen.

Palaeotemperature estimates from the oxygen-isotope compo- sitions of belemnites have been hampered by not knowing ancient seawater isotope compositions well enough. We have tackled this problem using Mg/Ca as a proxy for temperature and here, we present a ~2 Ma record of paired Mg/Ca and d18O measurements of Jurassic (Early Pliensbachian) belem- nites from the Asturian basin as a palaeo-proxy of seawater oxygen-isotope composition. From the combined use of the two approaches, we suggest a d18Ow composition of about ␣0.1& for the Jamesoni–Ibex zones. This value may have been increased by about 0.6& during the Davoei Zone due to the effect of waters with a different d18Ow composition. These findings illustrate the inaccuracy of using a globally homogeneous ice-free value of d18Ow = ␣1& for d18Ocarb- based palaeotemperature reconstructions. Our data suggest that previous palaeotemperatures calculated in the region from d18O values of belemnites may have been underesti- mated as the seawater oxygen isotopic composition could have been higher.

The Lotus Fortress tracksite in the Qijiang National Geological Park, in Qijiang District, Chongqing Municipality consists of two distinct assemblages associated with different surfaces (Qijiang Layers 1 and 2). The lower of these two assemblages, here labeled as the “Wupus-Pteraichnus ichnoassemblage” is dominated by multiple, mainly parallel trackways of a small tridactyl and five trackways of pterosaurs (Pteraichnus). The upper surface assemblage, here labeled as the “Caririchnium ichnoassemblage”, is dominated by the tracks of ornithopods (Caririchnium lotus). Here we give a detailed description of the Pteraichnus tracks and evaluate their paleoecological significance together with other reports of pterosaur tracks from East Asia.

A detailed structural analysis was carried out on the Jurassic rocks cropping out along the cliffs of La Conejera Inlet (Asturias, Spain). It includes a geological map and a distortion-free cross-section constructed via photogrammetric methods. La Conejera Inlet is located within the Asturian Basin, a Permian–Mesozoic extensional basin partially formed during the opening of the Bay of Biscay. It suffered selective basin inversion during a Cenozoic contraction responsible for the Pyrenees and its western prolongation along the north margin of the Iberian Peninsula. The study of the structures (folds, faults, joints and veins) of the hangingwall of two normal faults with opposite dip senses reveals that it underwent a later compressional stage in which one fault block acted as a buttress. The contractional deformation in the hangingwall, interpreted as a deformed rollover anticline with an associated antithetic fault, diminishes on moving away from one of the main faults. The positive inversion tectonics produced not only a buttressing effect, but it also involved a certain amount of reverse reactivation of one of the main faults that still preserves a normal displacement. The original normal motion would have taken place during the Middle?–Late Jurassic, related to an embryonic stage of the opening of the Bay of Biscay. The later contractional stage would have been caused by the Cenozoic Alpine shortening. The good outcrop quality allows a relative chronology for the observed structures to be established. Employing all the available information we tried to reconstruct the structure at depth and predict the detachment depth, and to estimate the amounts of extension (the present-day value and that before the compression) and compression.

Lower Pliensbachian (Ibex Zone) black shales in the Asturian Basin (N Spain) represent " transgressive " black shales intercalated in relatively shallower (bioclastic and bioturbated) marine facies. Sedimentological and stable isotope analysis (O and C from belemnite rostra) and correlation between two 18 km apart stratigraphic sections at the Asturian sea-cliffs (Playa de Vega: 4.4 m thick; Punta La Llastra: 7.8 m thick) allowed characterizing vertical and lateral trends of black shale-, storm-related bioclástic-and bioturbated muddy facies, within four sedimentary stages. The observed sedimentary trends have been mainly related to the interaction between: warming of superficial ocean water, long-term relative sea-level rise, and short-term tectonic pulses of differential subsidence controlling preferential accumulation of black shales in subsiding troughs. The comparison of available sedimentological and isotopic data from coeval sedimentary successions from other basins indicates at least a regional extension of the warming event (i.e. European and Nortwest Tethys basins). The slight diachroneity of the Lower Pliensbachian (Ibex Zone) black shales in the Asturian, Basque-Cantabrian and Lusitanian basins is probably reflecting the influence of the regional tectonic subsidence, which was superimposed to the long-term sea-level rise and the warming event.

A combined sedimentological, lithological and chemostratigraphical (Mg/Ca, δ13C, δ18O) analysis of the Lower Pliensbachian marl–limestone platform successions exposed along the Asturias coastline (northern Spain) has resulted in the characterization of high-frequency cycles. The highest-order sedimentary cycles (i.e. elementary cycles) are centimeter- to deciemeter-thick alternations of bioclastic and muddy laminated/burrowed facies, which do not match the marl–limestone couplets. They encompass three sedimentary stages: deposition from storm-density currents (bioclastic facies), dominant lateral advection of continental terrigenous mud accumulated on to an oxygen-deficient seafloor (laminated facies), and recovery of bottom oxygenation involving the burrowing of laminated sediments (burrowed facies). The close match between the number of elementary cycles recorded during the Jamesoni Subzone in Asturias and Yorkshire (Northern England) gives support to the idea of the influence of a regional climatic factor (i.e. millennial-scale cyclicity).

The late Kimmeridgian Tereñes Formation, exposed on the coast of Asturias, northern Spain, displays a complex pattern of directed changes of grain size, carbonate content, and skeletal concentrations. In its upper part, here investigated, the formation represents a protected shelf lagoon in which four major facies types are distinguished: The Nanogyra virgula mudstone (1) and the Corbulomima concentrations (2) are characterized by concentrations of small bivalves. The carbonate mudstone (3) contains pseudomorphs after gypsum crystals and thin crusts of gypsum, occasionally in connectionwith thinmicrobial layers. Finally, the silty to fine-sandy marlstone and micrite and marly silt (4) is highly bioturbated and contains amoderately diverse benthicmacrofauna. These facies indicate a generally quiet environment punctuated by brief episodes of high water energy. Two low-diversitymacrobenthic assemblages can be recognized, each of them strongly dominated by a single bivalve taxon. The Nanogyra virgula assemblage exhibits a higher diversity than the near-monospecific Corbulomima assemblage. The former lived inwell aerated waters of slightly reduced salinity, and the latter in dysoxic waters of more strongly reduced salinity. The environmental stress responsible for the extremely lowspecies richness and evenness is thought to be multifactorial, produced by reduced salinity, dysoxic conditions, and a soft substrate, and resulted in simple food chains. The eurytopic opportunist Corbulomima was the only element of the shelly macrobenthos that was able to thrive in the shelf lagoon under these conditions. It occurs in countless mm- to cm-thick pavements and shell beds which show evidence of winnowing, influence of weak currents, and occasionally of distal storms, as can be deduced from the orientation pattern of shells. These rhythmic Corbulomima concentrations are explained as reflecting small-scale climatic fluctuations between wetter, stormier conditions leading to mixing of the water masses and enabling colonization of the lagoonal floor by the bivalve, and drier, more tranquil conditions. The latter resulted in a stratified watermass and anoxia at the bottom. Superimposed on this rhythmic alternation are three higher orders of cycles which are partly climatic controlled, partly reflect changes in relative sea level.

The new ichnosubspecies Rhizocorallium jenense spinosus from the Late Sinemurian (Early Jurassic) of Asturias (northern Spain) is described. This ichnotaxon occurs in three outcrops (El Puntal, Punta Rodiles and Punta La Llastra), near the Villaviciosa estuary, belonging to the Buerres Member of the Rodiles Formation. Rhizocorallium jenense spinosus is similar in shape and size to the ichnospecies Rhizocorallium jenense (herein ichnosubspecies R. jenense jenense) in comprising short and more or less straight U-shaped spreite burrows, commonly obliquely oriented with respect to the bedding plane, but is characterized by the presence of spine-shaped protuberances on the outer margin of the arm. Number of observed spine-shaped protuberances per specimen is variable, being commonly 2–4. Protuberances form obtuse, equilateral or acute triangles. The apical end of the spine-shaped protuberance varies from pointed to rounded. The specimens were emplaced in soft or slightly stiffer substrates to firmgrounds. Recurrent distribution of the spine-shaped protuberances reveals a well programmed behavioural pattern of the tracemaker, previously unknown in Rhizocorallium. Several strategies are envisaged: (a) a cache strategy, implying that the tracemaker collected organic matter during favourable times and subsequently stored material in the spine-shaped protuberances for resource-poorer times, (b) a farming strategy, the spine-shaped protuberances being used for concentration of micro-organisms (bacteria, fungi), and (c) a brooding strategy of the tracemaker, revealing a relationship between brood care and oxygen provision, with the location of the spine-shaped protuberances on the external margin of the arms related to a better water circulation.

Avanzini, M., Piñuela, L. & García-Ramos, J.C. 2011: Late Jurassic footprints reveal walking kinematics of theropod dinosaurs. Lethaia, Vol. 45, pp. 238–252. This study describes a set of theropod footprints collected from the Late Jurassic Lastres Formation (Asturias, N Spain). The footprints are natural casts (tracks and undertracks) grouped into three morphotypes, which are characterized by different size frequency, L/W relationship and divarication angles: ‘Grallatorid’ morphotype, ‘Kayentapus–Magnoavipes’ morphotype, ‘Hispanosauropus’ morphotype. The tracks were produced in firm, stiff and soft sediments. The infills of deep tracks, which are typically formed in soft mud, lack fine anatomical details, but they can reveal the walk kinematics of the trackmaker through the morphology of internal track fills and sinking traces. In all footprints, a horizontal outwardly directed translation movement and rotation are recognizable. The amount and geometry of digit penetration in the ground also show a pronounced difference. It can be inferred from the described sample that different theropoda-related ichnogenera share common kinematics. □Asturias, dinosaur footprint, late jurassic, theropods, walking kinematics.

A very high-resolution chemostratigraphic study of elemental, stable-isotope and strontium-isotope ratios (Mg/Ca, δ 13C, δ 18O, and 87Sr/ 86Sr) performed on belemnites from two Lower Pliensbachian sections of the Asturian basin (northern Spain) is presented here for the first time.The samples have been screened for diagenetic alteration using cathodoluminescence and elemental analyses. A total of 162 well-preserved belemnites analysed show a δ 13C range between -1.4‰ and +2.8‰ V-PDB, with the lowest values recorded in the Jamesoni Zone and the highest values in the Ibex Zone. Maximum δ 18O values (-0.1‰ V-PDB) are recorded in the Jamesoni Zone, while minimum values (-3.1‰ V-PDB) are observed in the Ibex Zone. The δ 13C temporal trend of raw and running average values shows a positive excursion during the Ibex Zone, coinciding with development of organic facies. This carbon-isotope maximum seems to be reproduced in different basins around the world, suggesting a probably global effect for this event. The strontium-isotope stratigraphy reveals a trend comparable to the reference curve, with a steep descent from the uppermost part of the Jamesoni Zone to the Davoei Zone.The occurrence of a reasonably good correlation between δ 18O and Mg/Ca ratios suggests that both may be useful for the record of marine palaeotemperatures. Paired curves of averaged temperatures from both proxies indicate a near flat temporal trend of seawater temperatures during the Jamesoni Zone, followed by warming for the Ibex Zone. During the uppermost Ibex to lowermost Davoei zones the two curves show divergence. This divergence may be consistent with a brief episode of influx of warmer and saltier waters from the southern equatorial oceans (Tethys/Panthalassa) during the Ibex-Davoei transition, previously reported for other basins, followed by a return to cooler temperatures during the Davoei Zone. The latter suggests the interruption of the connection with the equatorial oceans in this basin, resulting in a greater influence of cooler waters from the northeastern parts of the European epicontinental sea.

In 1940 R.T. Bird of the American Museum of Natural History collected segments of a sauropod and a theropod trackway from a site in the bed (Glen Rose Formation; Lower Cretaceous) of the Paluxy River, in what is now Dinosaur Valley State Park (Glen Rose, Texas, USA). However, Bird left undocumented thousands of other dinosaur footprints from this and other Paluxy tracksites. In 2008 and 2009 our international team carried out fieldwork to create detailed photomosaics of extant Paluxy tracksites, using GIS technology to combine these with historic maps and photographs. We also made photographs, tracings, LiDAR images, and measurements of individual footprints and trackways. Paluxy dinosaur tracksites occur in more than one tracklayer, but the largest and most spectacular footprints occur in the Main Tracklayer, a 20-30 cm thick, homogeneous dolomudstone that is thickly riddled with vertical invertebrate burrows (Skolithos). There are two dinosaur footprint morphotypes in the Main Tracklayer: spectacular sauropod trackways (Brontopodus) and the far more numerous tridactyl footprints, most or all of which were made by large theropods (possible ornithopod prints occur in a tracklayer stratigraphically higher than the Main Tracklayer). Tridactyl footprints are highly variable in quality; Paluxy tracksites collectively constitute a natural laboratory for investigating how trackmaker-substrate interactions create extensive extramorphological variability from a single foot morphology. Trackways of bipedal dinosaurs show a "mirror-image" distribution, suggesting movement of animals back and forth along a shoreline. In contrast, most sauropod trackways head in roughly the same direction, suggesting passage of a group of dinosaurs. The trackways collected by R.T. Bird suggest that at least one theropod was following a sauropod.

The chondrichthyan faunas from the Late Jurassic of Asturias is reviewed in this work. All the material in this study (teeth, finspines and dorsal spines), currently under preparation, are part of the Museo del Jurásico de Asturias (Colunga) collections. This record is relatively scarce, and consists exclusively of hybodontiform sharks: Hybodontiformes indet., Asteracanthus, Hybodus, and Planohybodus. All specimens come from Tereñes and Lastres Formations (Kimmeridgian).

Wilhelm Schulz (1805-1877), known in Spain as Guillermo Schulz, was one of the most outstanding representatives of the geology and mining industry in Spain during the nineteenth century. Schulz is, likewise, the author detailing the first discoveries of dinosaurs and marine reptiles in Spain. In 1858 Schulz described a supposed dinosaur tooth from the Jurassic of Ruedes (Asturias) as belonging to a shark. Schulz's description, mainly the occurrence of crenu-lated edges, suggests that the tooth was that of a large theropod. It probably comes from the altered grey marls of the Upper Jurassic (Kimmeridgian) Lastres Formation. Although the exact year of the discovery before 1858 is not known, the Ruedes tooth (currently lost) is presumably the earliest known discovery of a dinosaur body fossil in the Iberian Peninsula. Moreover, Schulz mentioned in 1858 the discovery of plesiosaur remains from the Liassic near Villaviciosa (Asturias). The material probably comes from the Pliensbachian marls and limestone rhythmites (Jamesoni zone) of the Rodiles Formation. As no figure was provided and the specimen is currently lost, we have no definitive certainty about its affinities. However, it represents the earliest marine reptile fossil found in Spain.

Crocodylomorph footprints are described from the Late Jurassic (Kimmeridgian) coastal and deltaic units of the northern Spain (Asturias). They are included in the ichnogenus Hatcherichnus. Possible trackmakers are here interpreted as basal neosuchian crocodiles (including Thalattosuchia) such as Goniopholididae or Telosauridae.

Previously known from the Kimmeridgian–Portlandian of Dorset (UK) only, Protocupressinoxylon purbeckensis wood is reported here from the Kimmeridgian of Asturias (Spain) and Ajoie (Switzerland). The morphospecies taxonomy and nomenclature are discussed, and new supplementary illustrations are given. The P. purbeckensis tree was growing in dry strongly seasonal (tropophilous) environments, and the new occurrences suggest that such a climate prevailed on land all over southwestern Europe at the end of the Jurassic (Kimmeridgian sensu anglico – Portlandian). The review of fossil wood data indicates that such a stressful environment may have constrained terrestrial biocoenoses and their evolution at the Jurassic ⁄ Cretaceous boundary. But wood generic diversity curves are also strikingly similar to that drawn 20 years ago for nonmarine tetrapods, implying a fossil Lagersta¨tte effect.

This report describes an isolated footprint preserved as a natural cast (convex hyporelief) from the Lastres Fm. (Late Jurassic) of northern Spain. The track consists of a small isolated pentadactyl ectaxonic right manus footprint. It is very asymmetric, plantigrade, with digits and palm deeply marked on the substrate. Digit IV is the longest, digits II and I are nearly equal in length and only a little shorter than III and IV. The footprint morphology is typical of a lizard - like or "lacertoid" track. The general outline of the footprint, the width to length ratio approximately equal to 1, the marked plantigrady and the substantial similarity in length of digits IV-I are coherent with a Rhynchosauroidea manual print. The global record of Rhynchosauroides ichnogenus shows that this specimen represents the latest occurrence of the ichnogenus. The most probable trackmaker was possibly a rhyncocephalian reptile.

The diagenetic overprint in rhythmic hemipelagic successions can either enhance or change the original distribution of CaCO3, but it is difficult to evaluate its effect because in most field examples, it is not possible to distinguish between sedimentary and diagenetic features. The rhythmic succession of the Pliensbachian of Asturias (Spain) shows alternation of bioclastic and laminated/burrowed intervals. The original content of carbonate brought by storms from shallow areas was larger in the bioclastic horizons. However, there is a widespread mismatch between facies alternations and the observed lithological rhythms. The diagenetic redistribution of CaCO3 resulted in successive limestone–marl/clay couplets that do not match (either in number or in the location of the boundaries) the sedimentary cycles defined by facies alternations. We conclude that interpreting the limestone–marl rhythms as a direct response to primary changes is highly questionable, unless there is unequivocal proof of a sedimentary origin of the alternation of the two lithologies.