Otero R.A.,University of Chile |
Soto-Acuna S.,University of Chile |
Vargas A.O.,University of Chile |
Rubilar-Rogers D.,Area de Paleontologia
Cretaceous Research | Year: 2014
We describe a new specimen of an elasmosaurid plesiosaur from the upper Maastrichtian of central Chile. The specimen includes a relatively complete dorso-caudal series, a few cervical vertebrae, and a fragmentary pelvic girdle. The specimen is identified as a sub-adult non-artistonectine elasmosaurid (Sauropterygia, Plesiosauria) based on graphic bivariate analysis of the cervical vertebral proportions. The caudal vertebrae have distinctive features such as neural arches that are recurved cranially, with pedicels overlapping the dorso-posterior surface of the immediately anterior centrum, and terminal centra with two pairs of deep dorsal articulations for the neural arches. These unusual features are present in several late Maastrichtian adult specimens from the Quiriquina Formation of central Chile, and have been included within the hypodigm of the historic taxon Cimoliasaurus andium Deecke (nomen dubium). The specimen studied here likely represents the same taxon or a closely related form, showing slight differences in both size and ontogenetic stage. The preserved elements of this new skeleton afford comparison with several other late Maastrichtian specimens from Chile that were previously, albeit tentatively, referred to " C.andium". The similarity of these specimens suggests that the late Maastrichtian elasmosaurid diversity of central Chile (excluding aristonectines) may be represented by taxa with low morphological disparity, or by a single taxon. © 2014 Elsevier Ltd.
Rubilar-Rogers D.,Area de Paleontologia |
Otero R.A.,Area de Paleontologia |
Yury-Yanez R.E.,University of Chile |
Vargas A.O.,University of Chile |
And 2 more authors.
Journal of South American Earth Sciences | Year: 2012
In Chile, the record of dinosaurs in Jurassic and Cretaceous sediments is often restricted to footprints, with few skeletal remains. Tetanuran theropods are known in the Upper Jurassic, and bones of titanosaur sauropods in the Late Cretaceous, including partial skeletons (e.g. Atacamatitan chilensis Kellner et al.). Also from the late Cretaceous, an ornithopod vertebra, a pair of theropod teeth and one tarsometatarsus of a gaviiform bird (Neogaeornis wetzeli Lambrecht) have been reported. The Cenozoic fossil record comprises abundant and well-preserved marine birds from Eocene and Miocene units, with a specially abundant record of Sphenisciformes and less frequently, Procellariiformes. There is an excellent Miocene-Pliocene record of other birds such as Odontopterygiformes, including the most complete skeleton ever found of a pelagornithid, Pelagornis chilensis Mayr and Rubilar-Rogers. Fossil birds are also known from Pliocene and Pleistocene strata. A remarkable collection of birds was discovered in lacustrine sediments of late Pleistocene age associated to human activity. The perspectives in the study of dinosaurs in Chile are promising because plenty of material stored in institutional collections is not described yet. The record of Chilean dinosaurs is relevant for understanding the dynamics and evolution of this group of terrestrial animals in the western edge of Gondwana, while Cenozoic birds from the Region may contribute to the understanding of current biogeography for instance, the effect of the emergence and establishment of the Humboldt Current. © 2012 Elsevier Ltd.
Description of a bryozoan fauna from mud mounds of the Lebanza formation (lower Devonian) in the Arauz area (Pisuerga-Carrión province, Cantabrian zone, NW Spain) [Description dune faune de bryozoaires de type mud-mound de la Formation Lebanza (Dévonien inférieur) de la région de Arauz (province de Pisuerga-Carríon, zone cantabrique, nord-ouest de lEspagne)]
Ernst A.,University of Kiel |
Fernandez L.P.,University of Oviedo |
Fernandez-Martinez E.,Area de Paleontologia |
Vera C.,University of Oviedo
Geodiversitas | Year: 2012
A bryozoan fauna containing 16 species is described from a set of small mud mounds occurring in the Lebanza Formation (Lower Devonian) of the Arauz area, NW Spain. One genus with one species is new: the cystoporate Petalosis clarus n. gen., n. sp. Eleven new species are described: three cystoporates Altshedata hispanica n. sp., A. gracilis n. sp. and Fistulipora arauzensis n. sp.; four trepostomes: Neotrematopora tenuis n. sp., Leioclema arauzensis n. sp., Eridotrypella validaeformis n. sp. and Leptotrypella armata n. sp.; two rhabdomesine cryptostomes Orthopora spinosa n. sp. and Vidronovella elegantula n. sp.; and two fenestrates Rectifenestella exiliformis n. sp. and Tectulipora tuberculata n. sp. Two species were identified at genus and family level respectively: Eridopora sp. and Rhomboporidae sp. indet. Two identified species show palaeobiogeographic relations to the Lower Devonian of Altai, Mongolia, and Tajikistan respectively: Leioclema multiacanthoporum Astrova in Astrova & Yaroshinskaya, 1968 and Hemitrypa lasutkiniae Waschurova, 1964. The bryozoan fauna is dominated by cystoporates and trepostomes, followed by cryptostomes and fenestrates. These species display four different growth habits: encrusting (43.75%), ramose branched/encrusting (12.5%), ramose branched (25%), and reticulate (18.75%). Encrusting and encrusting/ramose growth habits dominate in all parts of mud mounds, whereas ramose branched and reticulate bryozoans are most abundant in the lower part of mounds, being rare in the upper parts. Despite their abundance, bryozoans cannot be regarded as the principal builders of the mud mounds, which apparently were mainly built by microbial communities. Nevertheless, bryozoans played the role of sediment binders (encrusting species), stabilizing the sediment, or exerted a baffling effect (fenestrates). © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.