Search results for "Sauria"
showing 10 items of 34 documents
Evidence of an Early Triassic age (Olenekian) in Argana Basin (High Atlas, Morocco) based on new chirotherioid traces.
2010
8 pages; International audience; New chirotherioid traces (Synaptichnium, Chirotherium, Brachychirotherium, Isochirotherium), are described in the Argana Basin (High Atlas of Morocco). Seeing that these ichnotaxa are frequent in the Triassic, their occurrence in outcrops formerly mapped as Permian (T2 Member) has required detailed sedimentological and paleontological studies of the fossiliferous site. These studies clearly show that the ichnite-bearing strata belong actually to the T3 Member of the “regional Triassic”, i.e. lower member of the Timezgadiwine Formation, the age of which was, in fact, unknown up to now. The description of these ichnospecies and their statistical comparison wit…
Turonian marine amniotes from the Opole area in southwest Poland
2018
A few isolated plesiosaurian and mosasauroid squamate teeth were collected from the Opole area in southwest Poland during the late nineteenth century. Calcareous nannofossil analysis of their associated rock matrix indicates an early Turonian age (nannofossil zone UC7; Mytiloides ex gr. labiatus and Inoceramus apicalis inoceramid zones), which is significant because this constitutes a globally enigmatic interval of marine amniote evolution. The Opole plesiosaurian teeth are attributable to polycotylids, but an indeterminate mesopodial was also recovered. They are similar to specimens from the Cenomanian-Turonian in the Saxonian Cretaceous Basin of Germany and the Chalk succession of England…
Dental microwear texture reflects dietary tendencies in extant Lepidosauria despite their limited use of oral food processing
2019
Lepidosauria show a large diversity in dietary adaptations, both among extant and extinct tetrapods. Unlike mammals, Lepidosauria do not engage in sophisticated mastication of their food and most species have continuous tooth replacement, further reducing the wear of individual teeth. However, dietary tendency estimation of extinct lepidosaurs usually rely on tooth shape and body size, which allows only for broad distinction between faunivores and herbivores. Microscopic wear features on teeth have long been successfully applied to reconstruct the diet of mammals and allow for subtle discrimination of feeding strategies and food abrasiveness. Here, we present, to our knowledge, the first de…
Response to formal comment on Myhrvold (2016) submitted by Griebeler and Werner (2017)
2018
In his 2016 paper, Myhrvold criticized ours from 2014 on maximum growth rates (Gmax, maximum gain in body mass observed within a time unit throughout an individual’s ontogeny) and thermoregulation strategies (ectothermy, endothermy) of 17 dinosaurs. In our paper, we showed that Gmax values of similar-sized extant ectothermic and endothermic vertebrates overlap. This strongly questions a correct assignment of a thermoregulation strategy to a dinosaur only based on its Gmax and (adult) body mass (M). Contrary, Gmax separated similar-sized extant reptiles and birds (Sauropsida) and Gmax values of our studied dinosaurs were similar to those seen in extant similar-sized (if necessary scaled-up) …
Dinosaur Metabolism and the Allometry of Maximum Growth Rate
2016
In his 2016 paper, Myhrvold criticized ours from 2014 on maximum growth rates (Gmax, maximum gain in body mass observed within a time unit throughout an individual’s ontogeny) and thermoregulation strategies (ectothermy, endothermy) of 17 dinosaurs. In our paper, we showed that Gmax values of similar-sized extant ectothermic and endothermic vertebrates overlap. This strongly questions a correct assignment of a thermoregulation strategy to a dinosaur only based on its Gmax and (adult) body mass (M). Contrary, Gmax separated similar-sized extant reptiles and birds (Sauropsida) and Gmax values of our studied dinosaurs were similar to those seen in extant similar-sized (if necessary scaled-up) …
Body coloration and mechanisms of colour production in Archelosauria: the case of deirocheline turtles
2019
Animal body coloration is a complex trait resulting from the interplay of multiple mechanisms. While many studies address the functions of animal coloration, the mechanisms of colour production still remain unknown in most taxa. Here we compare reflectance spectra, cellular, ultra- and nano-structure of colour-producing elements, and pigment types in two freshwater turtles with contrasting courtship behaviour,Trachemys scriptaandPseudemys concinna. The two species differ in the distribution of pigment cell-types and in pigment diversity. We found xanthophores, melanocytes, abundant iridophores and dermal collagen fibres in stripes of both species. The yellow chin and forelimb stripes of bot…
Sistemática, filogenia y paleobiología de Iguanodon galvensis (Ornithopoda, Dinosauria) del Barremiense inferior (Cretácico Inferior) de Teruel (Espa…
2017
En 1825, Gideon A. Mantell bautizó con el nombre de Iguanodon al animal al cual pertenecían unos dientes fósiles hallados en sudoeste de Inglaterra. Iguanodon fue el segundo género de dinosaurio en ser definido y a lo largo de la historia múltiples especies se han incluido dentro de este género de ornitópodo. No obstante, actualmente las únicas especies válidas de este icónico dinosaurio europeo del Cretácico Temprano son la especie tipo Iguanodon bernissartensis (Barremiense tardío-Aptiense) e Iguanodon galvensis (Barremiense temprano). Así, en esta Tesis Doctoral se estudian los fósiles de la segunda de las especies, I. galvensis, hallados en los depósitos del Barremiense inferior (Cretác…
Palaeohistology helps reveal taxonomic variability in exceptionally large temnospondyl humeri from the Upper Triassic of Krasiejów, SW Poland
2023
For more than twenty years, palaeontological excavations have been carried out at the Upper Triassic site of Krasiejów (south-west Poland), providing thousands of skeletal elements belonging to various tetrapod groups. However, almost all bones are preserved in a disarticulated state. This generates problems in taxonomic assignment among closely related groups, e.g., stereospondyl amphibians. As far as cranial elements, the pectoral girdle bones and the intercentra are very diagnostic, while all other remaining skeletal elements are difficult to unambiguously assign between either the capitosaurid Cyclotosaurus intermedius or the trematosaurid Metoposaurus krasiejowensis, both originating f…
A new styracosternan hadrosauroid (Dinosauria: Ornithischia) from the Early Cretaceous of Portell, Spain
2021
A new styracosternan ornithopod genus and species is described based on the right dentary of a single specimen from the Mirambell Formation (Early Cretaceous, early Barremian) at the locality of Portell, (Castellón, Spain).Portellsaurus sosbaynatigen. et sp. nov. is diagnosed by two autapomorphic features as well as a unique combination of characters. The autapomorphies include: the absence of a bulge along the ventral margin directly ventral to the base of the coronoid process and the presence of a deep oval cavity on the medial surface of the mandibular adductor fossa below the eleventh-twelfth tooth position. Phylogenetic analyses reveal that the new Iberian form is more closely related …
Redescription of Skrjabinodon medinae (García-Calvente, 1948) (Nematoda: Pharyngodonidae) from the cloaca of Podarcis pityusensis (Bosca, 1883) (Saur…
1992
Pharyngodon medinae Garcia-Calvente, 1948 (Nematoda: Pharyngodonidae) is redescribed from Podarcis pityusensis (Bosca, 1883) (Sauria: Lacertidae) of the Balearic Islands (Spain) and confirmed as a member of the genus Skrjabinodon Inglis, 1968. A systematic review of S. medinae and closely related species is also given. Parathelandros canariensis is referred to Skrjabinodon as a new combination and Parathelandros Magzoub et al., 1980 is dismissed as a junior homonym of Parathelandros Baylis, 1930.