Preservation of soft parts (collagen fibres, blood vessels and cells) in extinct vertebrates is rare and usually limited to fossilized bone and cartilage. Well-preserved coarse collagenous fibre bundles embedded in a mineralized matrix of tendons, as well as numerous hollow, tubular structures consistent morphologically with fibril bundles, blood vessels and associated cells, were identified in ossified tendons of Late Cretaceous ornithischians from North America and Central East Asia. Detailed, high-accuracy imaging, along with spectroscopic characterization of those fibrous structures and comparison with ossified tendons of modern-day turkeys, support the proposition that physiologically driven tendon ossification is common for avians and non-avian dinosaurs. The examined soft parts were preserved through the pathway of iron-induced crosslinking and alumino-silification, documenting a variety of pathways for the preservation of soft parts, depending on the burial environment. For the first time, the structure of dinosaur fossilized tendons is analysed in detail, revealing shared histogenetic principles with modern birds and the nature of preservation.

While the occurrence of skeletal pathologies in Middle Triassic marine reptiles has been poorly documented until now, massive accumulations of bone remains from the Germanic Basin provide the opportunities for documentation. Herein, we describe skeletal abnormalities in the Middle Triassic bone material from the Vossenveld Formation of Winterswijk, the Netherlands. The aim of the study is to distinguish in the studied bones pathologies resulting from malady or trauma and taphonomic alterations. Furthermore, an attempt was made to assess on how the pathologies also represent paleoecological data. Our survey led to the identification of one broken and healed bone, one case of abnormal coossification, and one case of posttraumatic fibro-osseous dysplasia. While the latter two pathologies give little insight into the ecology and function of the affected animals, the fractured dentary is attributed to Nothosaurus marchicus, a common sauropterygian macropredator. It proves that the individual survived long enough to heal, despite the injury hampering its hunting potential. One abnormally shaped humerus is interpreted as postmortem taphonomic deformation, emphasizing the necessity of utilization of detailed diagnostics to distinguish actual paleopathologies from nonbiological distortion.

Conservation of energy is one of the foundations of science, and in this paper, we use this principle to estimate the resting breathing rate of the dinosaur Plateosaurus trossingensis (see Fig. 1). Animals produce the energy necessary for life via chemical reactions in which biomolecules (such as glucose) react with oxygen to release CO2, H2O, and energy. The metabolism is determined from the animal’s reported mass growth curve (the mass of the animal as a function of age during its juvenile growth) using a model based on conservation of energy. The metabolism reveals the rate at which oxygen is used by the animal. The efficiency of oxygen extraction is assumed to be the same as observed in modern birds (which have a very efficient “one-way” breathing modality and are direct descendants of dinosaurs). Using the estimated concentration of oxygen in Earth’s atmosphere during the Late Triassic period yields the amount of air that P. trossingensis breathed each minute. Finally, the tidal volume (the volume of air inhaled in each breath) was used to calculate its resting breathing rate. This exercise has been used in introductory and intermediate courses on thermal physics, and the students find it empowering (and fun) to be able to gain this insight into the physiology of a dinosaur.