Phylogenetic analysis of Gondwanan basal eusauropods from the Early-Middle Jurasic of Patagonia, Argentina

Los eusaurópodos no neosaurópodos del Jurásico de Gondwana son especies clave para la comprensión de la evolución del clado Sauropoda, aunque sus relaciones fi logenéticas siguen sin estar bien resueltas. Sin embargo, gracias a la revisión del holotipo de uno de los taxones más importantes del Jurásico Medio temprano de la Formación Cañadón Asfalto, Patagosaurus fariasi, bastantes de sus hipótesis fi logenéticas han de ser puestas en duda, basadas en la nueva información osteológica recogida durante la redescripción del holotipo de Patagosaurus. La nueva hipótesis filogenética aquí presentada muestra una relación cercana entre Patagosaurus y Cetiosaurus, del Jurásico Medio del Reino Unido. La cercanía fi logenética de Patagosaurus con Barapasaurus, publicada en numerosos análisis fi logenéticos, no se obtuvo en este nuevo análisis. En este caso, Patagosaurus aparece como un taxón más derivado que la mayoría de saurópodos del Jurásico Medio y Superior, aunque más basal que Mamenchisaurus, Omeisaurus, Turiasauria y Neosauropoda. Otro taxón que se encuentra normalmente emparentado con Patagosaurus, Volkheimeria, en nuestro análisis aparece varios nodos más basalmente que Patagosaurus. Esto muestra, junto con la presencia de otros taxones de saurópodos de la Formación de Cañadón Asfalto, que una diversidad evolutiva alta existió en el suroeste de Gondwana en el Jurásico Medio temprano, un patrón que también está presente en otros grupos fósiles (e.g., terópodos).Gondwanan Jurassic non-neosauropod eusauropods are key for the understanding of sauropod evolution, although their phylogenetic interrelationships remain poorly understood. However, following the revision of the holotype of a key taxon from the early Middle Jurassic Cañadón Asfalto Formation Patagonia, Argentina, Patagosaurus fariasi, the phylogenetic affinities need to be tested with new osteological information gathered during the redescription of the holotype of Patagosaurus. A new phylogeny presented here shows a close affiliation of Patagosaurus with Cetiosaurus from the Middle Jurassic of the UK. The close relationship of Patagosaurus with Barapasaurus, often found in previous phylogenies, was not recovered here. Instead, Patagosaurus is retrieved as more derived than most Early and Middle Jurassic sauropods, although more basal to Mamenchisaurus, Omeisaurus, turiasaurians, and neosauropods. Another sauropod taxon found together with Patagosaurus, Volkheimeria, is retrieved several nodes more basal than the former, which shows, together with evidence of several other sauropod taxa in the Cañadón Asfalto Formation, that a high evolutionary diversity existed in Southwest Gondwana in the early Middle Jurassic, a pattern which is also seen in fossil groups other than sauropods (e.g., theropods).Fil: Holwerda, Femke Marleen. No especifíca;Fil: Pol, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; Argentin

Three-dimensional dental microwear in type-Maastrichtian mosasaur teeth (Reptilia, Squamata)

Mosasaurs (Squamata, Mosasauridae) were large aquatic reptiles from the Late Cretaceous that filled a range of ecological niches within marine ecosystems. The type-Maastrichtian strata (68–66 Ma) of the Netherlands and Belgium preserve remains of five species that seemed to have performed different ecological roles (carnivores, piscivores, durophages). However, many interpretations of mosasaur diet and niche partitioning are based on qualitative types of evidence that are difficult to test explicitly. Here, we apply three-dimensional dental microwear texture analysis (DMTA) to provide quantitative dietary constraints for type-Maastrichtian mosasaurs, and to assess levels of niche partitioning between taxa. DMTA indicates that these mosasaurs did not exhibit neatly defined diets or strict dietary partitioning. Instead, we identify three broad groups: (i) mosasaurs Carinodens belgicus and Plioplatecarpus marshi plotting in the space of modern reptiles that are predominantly piscivorous and/or consume harder invertebrate prey, (ii) Prognathodon saturator and Prognathodon sectorius overlapping with extant reptiles that consume larger amounts of softer invertebrate prey items, and (iii) Mosasaurus hoffmanni spanning a larger plot area in terms of dietary constraints. The clear divide between the aforementioned first two groups in texture-dietary space indicates that, despite our small sample sizes, this method shows the potential of DMTA to test hypotheses and provide quantitative constraints on mosasaur diets and ecological roles

Three-dimensional dental microwear in type-Maastrichtian mosasaur teeth (Reptilia, Squamata)

Mosasaurs (Squamata, Mosasauridae) were large aquatic reptiles from the Late Cretaceous that filled a range of ecological niches within marine ecosystems. The type-Maastrichtian strata (68–66 Ma) of the Netherlands and Belgium preserve remains of five species that seemed to have performed different ecological roles (carnivores, piscivores, durophages). However, many interpretations of mosasaur diet and niche partitioning are based on qualitative types of evidence that are difficult to test explicitly. Here, we apply three-dimensional dental microwear texture analysis (DMTA) to provide quantitative dietary constraints for type-Maastrichtian mosasaurs, and to assess levels of niche partitioning between taxa. DMTA indicates that these mosasaurs did not exhibit neatly defined diets or strict dietary partitioning. Instead, we identify three broad groups: (i) mosasaurs Carinodens belgicus and Plioplatecarpus marshi plotting in the space of modern reptiles that are predominantly piscivorous and/or consume harder invertebrate prey, (ii) Prognathodon saturator and Prognathodon sectorius overlapping with extant reptiles that consume larger amounts of softer invertebrate prey items, and (iii) Mosasaurus hoffmanni spanning a larger plot area in terms of dietary constraints. The clear divide between the aforementioned first two groups in texture-dietary space indicates that, despite our small sample sizes, this method shows the potential of DMTA to test hypotheses and provide quantitative constraints on mosasaur diets and ecological roles

Three-dimensional dental microwear in type-Maastrichtian mosasaur teeth (Reptilia, Squamata)

Mosasaurs (Squamata, Mosasauridae) were large aquatic reptiles from the Late Cretaceous that filled a range of ecological niches within marine ecosystems. The type-Maastrichtian strata (68–66 Ma) of the Netherlands and Belgium preserve remains of five species that seemed to have performed different ecological roles (carnivores, piscivores, durophages). However, many interpretations of mosasaur diet and niche partitioning are based on qualitative types of evidence that are difficult to test explicitly. Here, we apply three-dimensional dental microwear texture analysis (DMTA) to provide quantitative dietary constraints for type-Maastrichtian mosasaurs, and to assess levels of niche partitioning between taxa. DMTA indicates that these mosasaurs did not exhibit neatly defined diets or strict dietary partitioning. Instead, we identify three broad groups: (i) mosasaurs Carinodens belgicus and Plioplatecarpus marshi plotting in the space of modern reptiles that are predominantly piscivorous and/or consume harder invertebrate prey, (ii) Prognathodon saturator and Prognathodon sectorius overlapping with extant reptiles that consume larger amounts of softer invertebrate prey items, and (iii) Mosasaurus hoffmanni spanning a larger plot area in terms of dietary constraints. The clear divide between the aforementioned first two groups in texture-dietary space indicates that, despite our small sample sizes, this method shows the potential of DMTA to test hypotheses and provide quantitative constraints on mosasaur diets and ecological roles

Late Cretaceous sauropod tooth morphotypes may provide supporting evidence for faunal connections between North Africa and Southern Europe

The Cretaceous Kem Kem beds of Morocco and equivalent beds in Algeria have produced a rich fossil assemblage, yielding, amongst others, isolated sauropod teeth, which can be used in species diversity studies. These Albian-Cenomanian ( approximately 113-93.9 Ma) strata rarely yield sauropod body fossils, therefore, isolated teeth can help to elucidate the faunal assemblages from North Africa, and their relations with those of contemporaneous beds and geographically close assemblages. Eighteen isolated sauropod teeth from three localities (Erfoud and Taouz, Morocco, and Algeria) are studied here, to assess whether the teeth can be ascribed to a specific clade, and whether different tooth morphotypes can be found in the samples. Two general morphotypes are found, based on enamel wrinkling and general tooth morphology. Morphotype I, with mainly rugose enamel wrinkling, pronounced carinae, lemon-shaped to (sub)cylindrical cross-section and mesiodistal tapering towards an apical tip, shows affinities to titanosauriforms and titanosaurs. Morphotype II, characterized by more smooth enamel, cylindrical cross-section, rectangular teeth with no apical tapering and both labial and lingual wear facets, shows similarities to rebbachisaurids. Moreover, similarities are found between these northwest African tooth morphotypes, and tooth morphotypes from titanosaurs and rebbachisaurids from both contemporaneous finds from north and central Africa, as well as from the latest Cretaceous (Campanian-Maastrichtian, 83.6 Ma-66.0 Ma) of the Ibero-Armorican Island. These results support previous hypotheses from earlier studies on faunal exchange and continental connections between North Africa and Southern Europe in the Cretaceous

Sauropod dinosaur fossils from the Kem Kem and extended ‘Continental Intercalaire’ of North Africa : A review

The Cretaceous (likely Aptian-Cenomanian) Kem Kem beds of Morocco are famous for their fossil-richness, including theropods, and several sauropod body fossils, such as Rebbachisaurus garasbae, as well as isolated sauropod teeth. Deposits from this particular age, however, stretch across Algeria and Tunisia, with possibly contemporaneous fossiliferous beds also being known from Egypt and Niger. Although the sediments of North Africa have yielded more complete sauropod specimens in recent years dated to either Cenomanian or Campanian-Maastrichtian, in general, these sites are not well-known. A recent study on isolated sauropod teeth from Morocco and Algeria revealed that a diverse sauropod fauna existed, and, moreover, evidence has been found of sauropod migration from Africa to Europe in the Cretaceous. In order to provide a better overview of the sauropod presence in the Albian-Cenomanian of North Africa, an overview of all sauropod material known from this time is necessary. Therefore, several previous reports on sauropod fossils and teeth from the Kem Kem and the ‘Continental Intercalaire’ of North Africa are here reviewed and summarized

A derived sauropodiform dinosaur and other sauropodomorph material from the Late Triassic of Canton Schaffhausen, Switzerland

Although sauropodomorph dinosaurs have been known for a long time from the Late Triassic of central Europe, sauropodomorph diversity and faunal composition has remained controversial until today. Here we review sauropodomorph material from the Canton Schaffhausen, Switzerland. The material comes from three different but geographically close localities and represents at least three different taxa. Apart from the common genus Plateosaurus, the material includes remains of two different large, robustly built sauropodomorphs. One of these is described as a new taxon, Schleitheimia schutzi n. gen. et sp., on the basis of an unusual ilium and associated axial and appendicular material. Schleitheimia represents a derived basal sauropodiform and possibly the immediate outgroup to Sauropoda, and thus is the most derived sauropodomorph known from the Late Triassic of Europe. These results thus highlight the diversity of sauropodomorphs in the Late Triassic of central Europe and further indicate widespread sauropodomorph survival across the Triassic-Jurassic boundary

Ein neuer Dinosaurier aus dem Kanton Schaffhausen – Vorfahre der Giganten

Eine internationale Forschergruppe beschreibt in der aktuellen Ausgabe des Swiss Journal of Geosciences einen für die Wissenschaft neuen Dinosaurier aus dem Kanton Schaffhausen unter dem Namen Schleitheimia schutzi. Dabei stützen sich die Wissenschaftler sowohl auf ältere Funde eines lokalen Sammlers als auch auf Fossilien aus einer Grabung im Jahr 2016. Schleitheimia lebte vor etwa 210 Millionen Jahren in der Frühzeit der Dinosaurier und steht gemäss der Studie nahe am Ursprung der Sauropoden. Das ist jene Reptilgruppe, die sich in der Blütezeit der Dinosaurier zu den langhalsigen Giganten entwickeln sollte, die heute jedes Kind sofort als Dinosaurier erkennt. Eine Auswahl der in der Publikation beschriebenen Funde wird ab 1. Juli im Museum zu Allerheiligen in Schaffhausen der Öffentlichkeit vorgestellt

Sauropod dinosaur fossils from the Kem Kem and extended ‘Continental Intercalaire’ of North Africa: A review

The Cretaceous (likely Aptian-Cenomanian) Kem Kem beds of Morocco are famous for their fossil-richness, including theropods, and several sauropod body fossils, such as Rebbachisaurus garasbae, as well as isolated sauropod teeth. Deposits from this particular age, however, stretch across Algeria and Tunisia, with possibly contemporaneous fossiliferous beds also being known from Egypt and Niger. Although the sediments of North Africa have yielded more complete sauropod specimens in recent years dated to either Cenomanian or Campanian-Maastrichtian, in general, these sites are not well-known. A recent study on isolated sauropod teeth from Morocco and Algeria revealed that a diverse sauropod fauna existed, and, moreover, evidence has been found of sauropod migration from Africa to Europe in the Cretaceous. In order to provide a better overview of the sauropod presence in the Albian-Cenomanian of North Africa, an overview of all sauropod material known from this time is necessary. Therefore, several previous reports on sauropod fossils and teeth from the Kem Kem and the ‘Continental Intercalaire’ of North Africa are here reviewed and summarized