Uncertainties in the phylogeny of birds (Avialae) and their closest relatives have impeded
deeper understanding of early theropod flight. To help address this, we produced an updated …

Pterosaurs were the first vertebrates to achieve true flapping flight, but in the absence of living
representatives, many questions concerning their biology and lifestyle remain unresolved. …

Countershading was one of the first proposed mechanisms of camouflage [1, 2]. A dark dorsum
and light ventrum counteract the gradient created by illumination from above, obliterating …

This chapter will cover clade definitions, the relationships within clades as well as the occasional
controversial relationships between different clades. Phylogenies arising from a recent …

The Frankfurt specimen of the early-branching ceratopsian dinosaur Psittacosaurus is
remarkable for the exquisite preservation of squamous (scaly) skin and other soft tissues that …

The Mkv evolutionary model, based on minor modifications to models of molecular evolution,
is being increasingly used to infer phylogenies from discrete morphological data, often …

Body shape is a fundamental expression of organismal biology, but its quantitative reconstruction
in fossil vertebrates is rare. Due to the absence of fossilized soft tissue evidence, the …

Asymmetrical feathers have been associated with flight capability but are also found in species
that do not fly, and their appearance was a major event in feather evolution. Among non-…

Fluorescence using ultraviolet (UV) light has seen increased use as a tool in paleontology
over the last decade. Laser-stimulated fluorescence (LSF) is a next generation technique that …

Digital reduction is a striking evolutionary phenomenon that is clearly exemplified in theropod
dinosaurs by the functionally didactyl manus of tyrannosaurids, the flight-adapted manus …