Long bone histology of a eusuchian crocodyliform from the Upper Cretaceous of Spain: Implications for growth strategy in extinct crocodiles

[EN] The long bone histology of a Late Cretaceous eusuchian crocodyliform from the Iberian Peninsula reveals clear variations in the cortical structure which reflects changes in the speed of bone deposition (i.e., skeletal growth) related to ontogeny. The presence of secondary woven-fibred bone tissue in the perimedullar region of the cortex, and the existence of an external fundamental system in the most external periostic cortex, which is a proxy for somatic maturity and effective cessation of growth, challenges the former idea that the growth strategy of extinct crocodylians fit in the typical ectotherm condition, according to which these animals grew slowly during life under an indeterminate growth strategy. The analysed specimen lived for a minimum of 16 years and the highest preserved apposition rates took place in an advanced ontogenetic stage. The study suggests that the general aspects of the modern crocodylian growth strategy were already in place in some lineages by the Cretaceous. (C) 2016 Elsevier Ltd. All rights reserved.The research was supported by the Ministerio de Economia y Competitividad of Spain (Secretaria de Estado de Investigacion, Desarrollo e Innovacion, projects CGL2013-47521-P and CGL2014-53548-P), the European Regional Development Fund, and the Gobierno Vasco/Eusko Jaurlaritza (research group IT 834-13).Company Rodríguez, J.; Pereda-Suberbiola, X. (2017). Long bone histology of a eusuchian crocodyliform from the Upper Cretaceous of Spain: Implications for growth strategy in extinct crocodiles. Cretaceous Research. 72:1-7. https://doi.org/10.1016/j.cretres.2016.12.002S177

Notes on the pelvic armor of European ankylosaurs (Dinosauria: Ornithischia)

The pelvic armor elements in the ankylosaurian material from the Upper Cretaceous of Iharkut, Hungary are described here. Among these, a new articulated hip region of a small bodied ankylosaur is referred here to cf. Struthiosaurus sp. It preserves, uniquely among Late Cretaceous European ankylosaurs, an in situ pelvic armor composed of among others four, keeled, oval to circular osteoderms lying centrally and arranged longitudinally above the synsacral neural spines. This is the first indication of this type of pelvic osteoderm arrangement in an ankylosaur, increasing our knowledge on this poorly known part of the ankylosaur skeleton. Some additional pelvic osteoderms are also described that help to reconstruct and distinguish the pelvic armor of the two Late Cretaceous European ankylosaurs Struthiosaurus and Hungarosaurus. Both taxa have some fused parts in the pelvic armor but most probably neither of them had a single, fused pelvic shield as that of the Early Cretaceous Polacanthus. Interwoven texture on the ventral surface of the osteoderms, observed in both European taxa and known in other ankylosaurs (e.g. Polacanthus, Nodosaurus), is suggested here to be a characteristic feature of the non-keeled, fused pelvic armor elements of Ankylosauria. (C) 2017 Elsevier Ltd. All rights reserved

A new Cretaceous thyreophoran from Patagonia supports a South American lineage of armoured dinosaurs

The early evolution of thyreophoran dinosaurs is thought to have occurred primarily in northern continents since most evidence comes from the Lower and Middle Jurassic of Europe and North America. The diversification into stegosaurs and ankylosaurs is obscured by a patchy fossil record comprising only a handful of fragmentary fossils, most with uncertain phylogenetic affinities. Here we report the discovery of a new armoured dinosaur from the early Late Cretaceous of Argentina, recovered phylogenetically using various datasets either as a basal thyreophoran or a stem ankylosaur, closely related to Scelidosaurus. It bears unusual anatomical features showing that several traits traditionally associated with the heavy Cretaceous thyreophorans did not occur universally. Jakapil kaniukura gen. et sp. nov. is the first definitive thyreophoran species from the Argentinian Patagonia. Unlike most thyreophorans, it seems to show a bipedal stance, as in Scutellosaurus. Jakapil also shows that early thyreophorans had a much broader geographic distribution than previously thought. It is a member of an ancient basal thyreophoran lineage that survived until the Late Cretaceous in South America.The authors thank to Mariluan family for kindly allowing us the access to the fossiliferous locality of Cerro Policia and to the Secretaria de Cultura of the Rio Negro Province for allowing the respective permits; to the Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Agencia Nacional de Promocion de la Investigacion, el Desarrollo Tecnologico y la Innovacion (projects PICT 2014-0564 and PICT 2018-04598), the Fundacion Azara-Universidad Maimonides, the Spanish Ministerio de Ciencia, Innovacion e Universidades and the European Regional Development Fund (projects CGL2017-85038-P and PID2021-122612OB-I00), and the Gobierno Vasco/EJ (research group IT1418-19) for the funding. F. J. R. thanks to I. Diaz-Martinez, A. Martinelli, L. Leahey, R. Molnar, A. Vargas Milne, S. Soto Acuna, and M. Baron for digital material; to L. Pazo and J. Kaluza for the material preparation; to the members of the Area de Paleontologia of the Fundacion Azara, especially F. Garberoglio, L. Fernandez Dumont and J. P. Garderes, for all the helping; to R. Ponti for the thin sectioning, and I. Cerda for his advice on histological aspects; to S. Bogan, S. M. alvarez and J. Meluso for facilitate the access to the Fundacion Azara collections. S. A. acknowledges J. Kaluza for identifying key materials. Thanks to R. Glasgow for reviewing the English text of the manuscript. Special thanks to the reviewers Susannah Maidment, Victoria Arbour, and an anonymous reviewer, whose comments strongly improved the manuscript

Partial skull and endocranial cast of the ankylosaurian dinosaur Hungarosaurus from the Late Cretaceous of Hungary : implications for locomotion

A partial skull of ankylosaur from the Upper Cretaceous (Santonian) Csehbánya Formation in Iharkút and the endocranial cast taken from it are described. The morphology of the exoccipital, the elongated 'neck' region of the basioccipital, the shape of the occipital condyle, and the different flexure of the medulla relative to the forebrain unambiguously differentiate this specimen from the basicranium of Struthiosaurus, so it is assigned to Hungarosaurus sp. Whereas the endocranial cast reflects a brain generally similar to those of other ankylosaurs, the dorsally hypertrophied cerebellum (also present is Struthiosaurus transylvanicus) is quite unusual within the group suggesting a more sophisticated cerebral coordination of posture and movement, and perhaps a more cursorial locomotary habit than predicted for other ankylosaurs

Stelladens mysteriosus: A Strange New Mosasaurid (Squamata) from the Maastrichtian (Late Cretaceous) of Morocco

Mosasaurids, a clade of specialized marine squamates, saw a major adaptive radiation in the Late Cretaceous, evolving a wide range of body sizes, shapes, and specialized tooth morphologies. The most diverse known mosasaurid faunas come from the late Maastrichtian phosphates of Morocco. Here, we report an unusual new mosasaurid, Stelladens mysteriosus, based on a partial jaw and associated tooth crowns from lower Couche III phosphatic deposits at Sidi Chennane, Oulad Abdoun Basin, Morocco. Stelladens is characterized by short, triangular tooth crowns with a series of strong, elaborate, and serrated ridges on the lingual surface of the tooth, functioning as accessory carinae. Morphology of the teeth and associated jaw fragment suggest affinities with Mosasaurinae. No close analogues to the unique tooth morphology of Stelladens are known, either extant or extinct. It may have had an unusual and highly specialized diet, a specialized prey-capture strategy, or both. The diversity of mosasaurid teeth is much higher than that of plesiosaurs, ichthyosaurs, or extant marine mammals, and likely reflects both the ecological diversity of mosasaurids and complex developmental mechanisms responsible for tooth formation in mosasaurines. Mosasaurid diversity continued to increase up to the Cretaceous–Paleogene boundary.Research of XPS is financed by the Spanish Ministry of Science and Innovation (MCIN) and the European Regional Development Fund (FEDER) (research project PID2021-122612OB-I00), and by the Basque Country Gouvernment (research group IT1485-22). This study is carried out within the framework of the agreement between the universities of Bath and Cadi Ayyad

The first duckbill dinosaur (Hadrosauridae: Lambeosaurinae) from Africa and the role of oceanic dispersal in dinosaur biogeography

The Late Cretaceous saw distinctly endemic dinosaur faunas evolve in the northern and southern hemispheres. The Laurasian continents of North America and Asia were dominated by hadrosaurid and ceratopsian ornithischians, with tyrannosaurs as apex predators. In Gondwanan communities, including Africa, South America, India and Madagascar, titanosaurian sauropods dominated as herbivores and abelisaurids as predators. These patterns are thought to be driven by the breakup of Pangaea and formation of seaways limiting dispersal. Here, we report a new lambeosaurine hadrosaurid, Ajnabia odysseus gen. et sp. nov., from the upper Maastrichtian of Morocco, North Africa, the first Gondwanan representative of a clade formerly thought to be restricted to Laurasia. The new animal shows features unique to Hadrosauridae and specifically Lambeosaurinae. Phylogenetic analysis recovers it within Arenysaurini, a clade of lambeosaurines previously known only in Europe. Biogeographic modelling shows that lambeosaurines dispersed from Asia to Europe, then to Africa. Given the existence of large, persistent seaways isolating Africa and Europe from other continents, and the absence of the extensive, bidirectional interchange characterizing land bridges, these patterns suggest dispersals across marine barriers, similar to those seen in Cenozoic mammals, reptiles, and amphibians. Dispersal across marine barriers also occurs in other hadrosaurid lineages and titanosaurian sauropods, suggesting oceanic dispersal played a key role in structuring Mesozoic terrestrial dinosaur faunas

Registro fósil precuaternario de tetrápodos en los Pirineos occidentales

El estudio de los niveles fosilíferos continentales y marinos del Cretácico Superior y del Terciario de la Región Vasco-Cantabrica (Sinclinorio Subcantábrico) y cuencas surpirenaicas adyacentes (Cuenca de Pamplona, Sector Noroccidental de la Depresión del Ebro) ha puesto de manifiesto su potencial paleontológico en restos fósiles de vertebrados. Algunos de estos yacimientos son de gran relevancia en el Cretácico final de Europa, incluyendo nuevas especies de tortugas, escamosos, cocodrilos, dinosaurios y mamíferos. En la misma cantera del yacimiento alavés de Zambrana, compuesta principalmente por reptiles y mamíferos, es de gran interés paleontológico y contribuye a un mejor conocimiento de las faunas del Eoceno superior de la Península Ibérica. En Zambrana se ha reconocido hasta la fecha varias nuevas especies de perisodáctilos ecuoideos. En el Neogeno, se han descubierto nuevas localidades del Mioceno (Rambliense, Aragoniense) en las Bardenas Reales de Navarra y otras áreas colindantes de la Cuenca del Ebro, que han proporcionado restos de anfibios, escamosos, tortugas, cocodrilos, aves y varios grupos de mamíferos. Por otro lado, una notable variedad de icnofacies de aves y mamíferos ha sido hallada en diferentes afloramientos de los potentes depósitos marinos litorales (Eoceno superior) y continentales (Oligoceno-Mioceno inferior) de la Alta Navarra

Los dinosaurios del Maastrichtiense superior de Huesca y su importancia en el estudio de la extinción del límite Cretácico/Terciario

To document a global extinction of dinosaurs a Cretaceous fossil record of dinosaurs from many areas around the world is required. Most of the latest Cretaceous dinosaur localities have been discovered throughout the central interior of North America, but no accurate information was hitherto known from other areas. The new dinosaur findings in the Pyrenees of Huesca can help to evaluate the dinosaur extinction pattern in Europe

Dinosauro teropodoen hortzak eta dietan duten islapena

Dinosauro teropodoak nahiko urriak dira erregistro fosilean eta, askotan, aurkitutako fosil bakarrak hortz isolatuak dira. Teropodoen hortzekin, ordea, azterketa paleontologiko anitz egin daitezke, metodologia kualitatibo eta kuan-titatibo mota desberdinak erabiliz. Hortzetatik abiatuz, teropodoen biosistematika burutu eta talde honen erregistro fosila eta paleobiodibertsitatea ezagutu daitezke, baita hainbat diziplina paleobiologikoren azterketa egin ere, hala nola paleoekologia (iraganeko bizidunek beren artean eta ingurunearekin duten erlazioaren azterketa) eta paleobiogeografia (iraganeko bizidu-nen banaketa biogeografikoaren azterketa). Azterketa paleoekologiko bat dinosauro hauen dieta ezagutzea litzateke. Tero-podoen lehendabiziko ordezkariek hortz zifodontoak (laban itxurakoak) zituzten; hortz hauek aproposak dira haragia eba-kitzeko. Hortz pakidontoek (banana gisakoak) zifodontoek baino erresistentzia handiagoa erakusten dute. Kate trofikoaren goialdean dauden teropodo haragijaleetan agertzen dira eta hezurrak txikitzea eta haragian ebakidura zabalak egitea ahalbi-detzen zieten dinosauroei. Hortzeria konidontoa (hortz lateral konikodun hortzeria) zulatzeko eta harrapakinak eusteko da egokia, eta dinosauro iktiofago, herbiboro eta intsektiboro batzuetan garatu zen. Hortzeria folidontodun teropodoei, hau da, hosto itxurako hortzak dituztenei, dieta mota ezberdinak esleitu zaizkie; hala nola haragijalea, intsektiboroa, omniboroa edo herbiboroa. Nahiz eta dinosauro teropodoek hortzeria mota ezberdinak izan, batzuek hortzen galera erakusten dute. Edentu-lismoa (hortzen galera partziala edo osoa) teropodo talde ezberdinetan gertatu zen independenteki. Edentulismoaren zerga-tia jorratzen duten hipotesi asko proposatu diren arren, argi dago hortz gabeko moko batek funtzio asko bete ditzakeela, die-tan besteak beste, eta, beraz, berrikuntza ebolutibo garrantzitsua izan zela dinosauro teropodo ez-hegaztietan eta hegaztietan. Izan ere, gaur egun, hortz gabeko hegaztiak dira bizirik dirauten dinosauro bakarrak.; Isolated theropod teeth are the most common elements of this dinosaur clade found in the fossil record. This has led to the development of different qualitative, quantitative and phylogenetic methodologies in the study of isolated theropod teeth. This research has applications in systematic palaeontology, palaeobiodiversity, palaeoecology, and palaeo-biogeography. Moreover, the theropod teeth can inform us about the diet of these dinosaurs. Ziphodont (blade-like) teeth are suitable for cutting flesh; this dentition type is the ancestral theropod condition. Pachydont (banana-like) teeth show greater strength than ziphodont teeth. Pachydonty is present in carnivorous theropods that are at the top of the food chain and are able to crush bones and make wide incisions in the flesh. Conidont (conical) teeth are suitable for drilling and hold-ing prey. Conidonty developed in theropods with ichthyophagous, herbivorous, and insectivorous diets. Folidonty (leaf-shaped lateral crowns) occurs in theropods consuming distinct types of food, such as carnivores, insectivores, omnivores, or herbivores, including species of different clades. Edentulism has developed independently in several different theropod clades. Many hypotheses have been proposed to address the origin of edentulism in theropods; it is undeniable that a tooth-less beak can perform many functions and has therefore been an important evolutionary innovation in non-avian theropods and birds. In fact, toothless birds are the only theropods left alive today