Structure of the upper ice mantle of Triton

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Nuevos datos sobre los dinosaurios terópodos (Saurischia: Theropoda) del Cretácico superior de los Pirineos Sur-Centrales (Huesca y Lleida)

Six new theropod teeth recovered trom the Blasi 1-3 sites (Upper Maastrichtian) in Arén (Huesca province, Spain) are described and added to the twenty six teeth already known from these and other five localities of Late Campanian-Early Maastrichtian age from the Arén and Tremp formations (Figuero1a 2, Fontllonga 6, L'Abeller, Montrebei and Vicari 4, Lleida province). Eleven theropod teeth morphotypes are recognised: one belonging to a big size theropod of indeterminate family (Theropoda indet.), one small Coelurosauria indet. with unserrated teeth, the enigmatic Euronychodon sp, and eight morphotypes of cf. Dromaesauridae indet. with different denticle morphology and serration density (which would represent four five different taxa). The tooth previously described in the Upper Campanian of Lleida as "Richardoestesia Like" could also be assigned to cf. Dromaeosauridae indet. Theropod diversity in our sites is apparently similar to that of the rest of Europe, and increases through the Campanian-Maastrichtian transition, although our small samples is biased towards the youngest sites

Dinosaur swim tracks from the Lower Cretaceous of La Rioja, Spain: An ichnological approach to non-common behaviours

The reconstruction of behavioural patterns performed by non-avian dinosaurs is an important task of palaeontology in order to globally understand how these animals interacted with their environment. Their relation with aquatic lifestyles has always been an intriguing question that has been extensively studied during the last decades, especially focused on some specific groups. The present work describes a new tracksite with 27 swimming tracks located in a fluvial setting from the Lower Cretaceous Urbion Group of La Rioja (Spain). They are preserved as natural casts with sizes between 8.5 and 29.2 cm and a predominant orientation. The tracks have been classified into 6 different morphotypes according to their morphology, and grouped into 5 different categories depending on the different pes-substrate interactions, following the proposal of Romilio et al. (2013). Some tracks were produced while the animal was moving in partial or complete buoyancy, and displacement was conducted by water and sediment impulsion, not just a mere paddling. Other tracks could be impressed in a bottom-walked, when the trackmaker touched the digit tips on the ground vertically or sub-vertically. This new tracksite confirms the capabilities of some groups of non-avian dinosaurs to interact with shallow water environments where they could print their pedes as they moved, either in complete buoyancy or during a displacement with some vertical component in the water column. It also contributes to the better understanding of swimming track morphologies as especially dependent on pes-sediment interaction and environment more than differences in pes configuration itself, causing the high variability of swimming footprints even when they belong to the same trackway. The classification of swimming tracks and footprints into categories dependent on the pes-substrate interaction could be a good guiding principle to avoid problematics about ichnotaxonomical definition.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEUniversidad de La RiojaConsejeria de Educacion y Cultura (Gobierno de La Rioja)Instituto de Estudios RiojanosMinisterio de Ciencia, Innovación y UniversidadesEuropean Regional Development FundUniversidad del País VascoMinisterio de Ciencia e Innovaciónpu

Actividades educativas en el yacimiento de vertebrados miócenos de Somosaguas (Universidad Complutense, Pozuelo de Alarcón, Madrid)

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

The biota of the Upper Cretaceous site of Lo Hueco (Cuenca, Spain)

The Late Cretaceous (Campanian-Maastrichtian) fossil site of Lo Hueco was recently discovered close to the village of Fuentes (Cuenca, Spain) during the cutting of a little hill for installation of the railway of the Madrid-Levante high-speed train. To date, it has yielded a rich collection of well-preserved Cretaceous macrofossils, including plants, invertebrates, and vertebrates. The recovered fossil assemblage is mainly composed of plants, molluscs (bivalves and gastropods), actinopterygians and teleosteans fishes, amphibians, panpleurodiran (bothremydids) and pancryptodiran turtles, squamate lizards, eusuchian crocodyliforms, rhabdodontid ornithopods, theropods (mainly dromaeosaurids), and titanosaur sauropods. This assemblage was deposited in a near-coast continental muddy floodplain crossed by distributary sandy channels, exposed intermittently to brackish or marine and freshwater flooding as well as to partial or total desiccation events.The Konzentrat-Lagerstatt of Lo Hueco constitutes a singular accumulation of fossils representing individuals of some particular lineages of continental tetrapods, especially titanosaurs, eusuchians and bothremydid turtles. In the case of the titanosaurs, the site has yielded multiple partial skeletons in anatomical connection or with a low dispersion of their skeletal elements. A combination of new taxa, new records of taxa previously known in the Iberian Peninsula, and relatively common taxa in the European record compose the Lo Hueco biota. The particular conditions of the fossil site of Lo Hueco and the preliminary results indicate that the analysis of the geological context, the floral and faunal content, and the taphonomical features of the site provide elements that will be especially useful for reassess the evolutionary history of some lineages of European Late Cretaceous reptiles.Peer reviewe

Los dinosaurios terópodos del Cretácico Superior de la Cuenca de Tremp (Pirineos Sur-Centrales, Lleida)

Se describe nuevo material de dinosaurios terópodos de Cretácico Superior de la Cuenca de Tremp: trece dientes aislados de terópodo procedentes de cuatro yacimientos, Fontllonga 6 y Figuerola 2, en el sinclinal de Ager, y Vicari 4 y Montrebey en el sinclinal de Tremp, pueden separarse en tres tipos. Los dientes pertenecientes al primero poseen dentículos distales y en ocasiones mesiales con forma de cincel y corresponden a cuatro morfotpios de Cromaeosauridae. El segundo son tres dientes de pequeño tamaño y carenas sin dentículos que han sido identificados como Coelurosauria indet. El último tipo corresponde a un terópodo de gran tamaño que ha sido identificado como Theropoda indet. Gracias a la precisa datación de los yacimientos es posible establecer una sucesión cronoestratigráfica para los terópodos del Cretácico Superior por primera vez en Europa y hacer un análisis de su diversidad a lo largo de este período. [ABSTRACT] New Upper Cretaceous theropod dinosaur material from the Tremp Basis is described. Thirteen isolated theropod teeth coming from four outcroups, Fontllonga 6 y Figuerola 2 in the Ager synclinal, and Vicari 4 and Montrebey in the Tremp synclinal, can be separated in tree types. The teeth that belong to the first type have distal and ocasionally mesial chisel-like denticles and are attibuted to four Dromaeosauridae morphotypes. The second type corresponds to three teeth of smaller size and carinae swithout denticles and has been identified as Coelurosauria. The third type belongs to a large theropod and hs been identified as Theropoda indet. Thanks to the localities' accurate dating, it is possible for the first time in Europe to establish a chronostatigrahiocal succesion of theopods for the Upper Cretaceous and to make an analysis of their diversity through this period

Humans Running at Stadiums and Beaches and the Accuracy of Speed Estimations from Fossil Trackways

The concept of dynamic similarity between mechanical properties of vertebrates and engineered structures has served in previous work to suggest that there is a power law relationship between vertebrate speeds and stride length. This relationship, with some additional assumptions about hind limb height, has permitted the calculation of speeds from fossil trackways of dinosaurs. However, there are claims that uncertainties are large. In this work we analyze the accuracy of speed calculations for fossil vertebrates based on fossil trackways by using data derived from both athletic competitions and an experiment with humans walking and running on a beach. Our results show that although there are somewhat different running regimes, in general terms human speed can be described in a simple way, and differences between observed and predicted speeds usually are no more than 10–15%. Thus, while recognizing that some uncertainty remains in the estimation of hind limb height, we conclude that reliable speed calculations can be obtained from vertebrate fossil trackways. Our results also show that very reliable speed estimates can be obtained from human fossil trackways directly from stride length measurements

Humanos en la pista y en la playa: implicaciones sobre la velocidad de los dinosaurios

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

The hand structure of Carnotaurus sastrei (Theropoda, Abelisauridae): implications for hand diversity and evolution in abelisaurids.

Carnotaurus sastrei is an abelisaurid dinosaur from the Late Cretaceous of Argentina that has very reduced, but robust, forelimbs and derived hands with four digits, including a large, conical-shaped metacarpal IV lacking an articulation for a phalanx. The analysis presented in this work highlights a series of additional autapomorphies of C. sastrei. For example, the proximal phalanges are longer than the metacarpals in digits II and III, and digit III includes only one phalanx besides the ungual. The hand of Carnotaurus shares several features with those of Aucasaurus and Majungasaurus, but the hands of the latter genera also display autapomorphies, indicating that the diversity in abelisaurid hand structure is similar to the diversity of cranial protuberances of these dinosaurs

Identification of a large anguimorph lizard (Reptilia, Squamata) by an articulated hindlimb from the upper Maastrichtian (Upper Cretaceous) of Basturs-1 (Lleida, Spain)

Appendicular remains of squamate reptiles are barely described in the fossil record due to their low preservational potential and generally poor diagnostic information. Not many squamate fossil individuals preserve appendicular bony elements, these being mainly restricted to the rare articulated specimens found in a limited number of localities with specific conditions that favor exceptional preservation. Detailed descriptions of these bones, especially tarsals and metatarsals, are thus scarce in the literature due to the lesser relevance given to these elements in most anatomical descriptions. In this study we analyze an unpublished fossil specimen from the Maastrichtian of Basturs-1 (Lleida, Catalonia, Spain) corresponding to several articulated appendicular pes bones of a possible member of Varaniformes. We also provide detailed insights on the anatomy of the tarsalia and metatarsalia, particularly in anguimorphs. The fossil specimen here described, with an estimated snout-vent length (SVL) of ∼581 mm, reveals the putative varaniform from Basturs-1 as one of the largest Mesozoic terrestrial lizards, and possibly the largest from the European fossil record. Previous observations of an association between large lizards and dinosaur nesting sites are further supported by the find of this giant form in a locality known for the presence of numerous dinosaur eggs