Over the past two decades, the development of methods for visualizing and analysing specimens digitally, in three and even four dimensions, has transformed the study of living and fossil organisms. However, the initial promise that the widespread application of such methods would facilitate access to the underlying digital data has not been fully achieved. The underlying datasets for many published studies are not readily or freely available, introducing a barrier to verification and reproducibility, and the reuse of data. There is no current agreement or policy on the amount and type of data that should be made available alongside studies that use, and in some cases are wholly reliant on, digital morphology. Here, we propose a set of recommendations for minimum standards and additional best practice for three-dimensional digital data publication, and review the issues around data storage, management and accessibility.

Gastralia are dermal ossifications situated in the ventral abdominal wall. Gastralia may be plesiomorphic for tetrapods, but are only retained in extant Crocodylia and Sphenodon, and possibly as part of the chelonian plastron. In contrast to previously published reports, a similar structural configuration of the gastralia is shared throughout prosauropods and (non-ornithurine) theropods. Within the Prosauropoda and Theropoda, the gastralial system consists of approximately 8 to 21 metamerie rows. Each row consists of four bones: two lateral and two medial rods. Gastralia of the cranialmost or caudalmost rows may coalesce, forming a median chevron-shaped gastralium. The lateral gastralia articulate in parallel with the medial gastralia in an elongated groove. The medial gastralia imbricate with contralateral gastralia along the ventral midline, creating a series of cranially directed chevrons. Thus all the gastralia are connected to one another, and operate as a single functional unit. The bones r...

Pterosaurs, enigmatic extinct Mesozoic reptiles, were the first vertebrates to achieve true flapping flight. Various lines of evidence provide strong support for highly efficient wing design, control, and flight capabilities. However, little is known of the pulmonary system that powered flight in pterosaurs. We investigated the structure and function of the pterosaurian breathing apparatus through a broad scale comparative study of respiratory structure and function in living and extinct archosaurs, using computer-assisted tomographic (CT) scanning of pterosaur and bird skeletal remains, cineradiographic (X-ray film) studies of the skeletal breathing pump in extant birds and alligators, and study of skeletal structure in historic fossil specimens. In this report we present various lines of skeletal evidence that indicate that pterosaurs had a highly effective flow-through respiratory system, capable of sustaining powered flight, predating the appearance of an analogous breathing system in birds by approximately seventy million years. Convergent evolution of gigantism in several Cretaceous pterosaur lineages was made possible through body density reduction by expansion of the pulmonary air sac system throughout the trunk and the distal limb girdle skeleton, highlighting the importance of respiratory adaptations in pterosaur evolution, and the dramatic effect of the release of physical constraints on morphological diversification and evolutionary radiation.

Birds and crocodylians, the only living archosaurs, are generally believed to employ pelvic girdle movements as a component of their respiratory mechanism. This in turn provides a phylogenetic basis for inferring that extinct archosaurs, including dinosaurs, also used pelvic girdle breathing. I examined lung ventilation through cineradiography (high–speed X–ray filming) and observed that alligators indeed rotate the pubis to increase tidal volume, but did not observe pelvic girdle movement contributing to lung ventilation in guinea fowl, emus or tinamous, despite extensive soft–tissue motion. Re–examination of fossil archosaurs reveals that pubic rotation evolved in basal crocodyliforms and that pelvic girdle breathing is not a general archosaurian mechanism. The appearance of pelvic aspiration in crocodyliforms is a striking example of the ability of amniotes to increase gas exchange or circumvent constraints on respiration through the evolution of novel accessory breathing mechanisms.