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Bermudez-Rochas D.D.,University of Cantabria | Delvene G.,Instituto Geologico Y Minero Of Espana | Ruiz-Omenaca J.I.,Museo del Jurasico de Asturias MUJA | Ruiz-Omenaca J.I.,University of Oviedo
Lethaia | Year: 2013

Here, we present evidence of possible vertebrate predation on freshwater bivalves from the Lower Cretaceous strata of the Cameros Basin (Spain). The described collection contains the largest number of vertebrate-inflicted shell injuries in freshwater bivalve shells yet reported in the Mesozoic continental record. Several types of shell damage on fossil shells of Protopleurobema numantina (Bivalvia: Unionoida) are described and their respective modes of formation interpreted in the context of morphological attributes of the shell injuries and the inferred tooth morphology of predators that could have inflicted such injuries. Detailed study of these bite marks shows similarities with the well-documented injuries in the shells of marine molluscs, namely ammonoids, that have likewise been attributed to reptilian predators. The most parsimonious interpretation suggests crocodiles as the vertebrates interacting with the bivalves in the Cameros Basin. □Barremian-Aptian; bite marks; freshwater bivalves; predation; reptile; Unionoida. © 2012 The Authors, Lethaia © 2012 The Lethaia Foundation. Source

An ornithopod dinosaur postcranial skeleton from the Early Cretaceous of Galve (Teruel province, Spain), assigned to Iguanodon bernissartensis by the French paleontologist Albert de Lapparent in 1960, is redescribed. It comes from La Maca 3 locality, early Barremian in age (Camarillas Formation) and it is made of several cervical vertebrae, fragmentary remains of the dorsal and sacral series, several caudal vertebrae, fragments of cervical, dorsal and sternal ribs, fragments of chevrons and ossified tendons, and an incomplete left hip. It has been identified as an «iguanodontid» (i.e., a non-hadrosaurid iguanodontoid) by the presence of a deep prepubic blade and the absence of antitrochanter on ilium. The skeleton represents a new iguanodontoid taxon, Delapparentia turolensis nov. gen et sp., characterized by the following autapomorphies: 1) posterior dorsal ribs with long, parallel and unfused capitulum and tuberculum, 2) ossified sternal ribs, and 3) straight and lateromedially expanded preacetabular process of ilium (convergent in Zalmoxes). It also presents a combination of anterior dorsal ribs with a pneumatic foramen, and a ischium of big size in relation to ilium. Source

Young M.T.,University of Edinburgh | Brusatte S.L.,American Museum of Natural History | Brusatte S.L.,Columbia University | de Andrade M.B.,Federal University of Rio Grande do Sul | And 8 more authors.
PLoS ONE | Year: 2012

Background: Dakosaurus and Plesiosuchus are characteristic genera of aquatic, large-bodied, macrophagous metriorhynchid crocodylomorphs. Recent studies show that these genera were apex predators in marine ecosystems during the latter part of the Late Jurassic, with robust skulls and strong bite forces optimized for feeding on large prey. Methodology/Principal Findings: Here we present comprehensive osteological descriptions and systematic revisions of the type species of both genera, and in doing so we resurrect the genus Plesiosuchus for the species Dakosaurus manselii. Both species are diagnosed with numerous autapomorphies. Dakosaurus maximus has premaxillary 'lateral plates'; strongly ornamented maxillae; macroziphodont dentition; tightly fitting tooth-to-tooth occlusion; and extensive macrowear on the mesial and distal margins. Plesiosuchus manselii is distinct in having: non-amblygnathous rostrum; long mandibular symphysis; microziphodont teeth; tooth-crown apices that lack spalled surfaces or breaks; and no evidence for occlusal wear facets. Our phylogenetic analysis finds Dakosaurus maximus to be the sister taxon of the South American Dakosaurus andiniensis, and Plesiosuchus manselii in a polytomy at the base of Geosaurini (the subclade of macrophagous metriorhynchids that includes Dakosaurus, Geosaurus and Torvoneustes). Conclusions/Significance: The sympatry of Dakosaurus and Plesiosuchus is curiously similar to North Atlantic killer whales, which have one larger 'type' that lacks tooth-crown breakage being sympatric with a smaller 'type' that has extensive crown breakage. Assuming this morphofunctional complex is indicative of diet, then Plesiosuchus would be a specialist feeding on other marine reptiles while Dakosaurus would be a generalist and possible suction-feeder. This hypothesis is supported by Plesiosuchus manselii having a very large optimum gape (gape at which multiple teeth come into contact with a prey-item), while Dakosaurus maximus possesses craniomandibular characteristics observed in extant suction-feeding odontocetes: shortened tooth-row, amblygnathous rostrum and a very short mandibular symphysis. We hypothesise that trophic specialisation enabled these two large-bodied species to coexist in the same ecosystem. © 2012 Young et al. Source

Armendariz M.,Instituto Geologico Y Minero Of Espana | Rosales I.,Instituto Geologico Y Minero Of Espana | Badenas B.,University of Zaragoza | Pinuela L.,Museo del Jurasico de Asturias MUJA | And 3 more authors.
Terra Nova | Year: 2013

Palaeotemperature estimates from the oxygen-isotope compositions 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 δ18O measurements of Jurassic (Early Pliensbachian) belemnites from the Asturian basin as a palaeo-proxy of seawater oxygen-isotope composition. From the combined use of the two approaches, we suggest a δ18Ow 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 δ18Ow composition. These findings illustrate the inaccuracy of using a globally homogeneous ice-free value of δ18Ow = -1‰ for δ18Ocarb-based palaeotemperature reconstructions. Our data suggest that previous palaeotemperatures calculated in the region from δ18O values of belemnites may have been underestimated as the seawater oxygen isotopic composition could have been higher. © 2013 John Wiley & Sons Ltd. Source

Armendariz M.,Instituto Geologico Y Minero Of Espana | Rosales I.,Instituto Geologico Y Minero Of Espana | Badenas B.,University of Zaragoza | Aurell M.,University of Zaragoza | And 3 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2012

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. © 2012 Elsevier B.V. Source

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