During the Mesozoic, various groups of reptiles underwent a spectacular return to an aquatic
life, colonizing most marine environments. They were highly diversified both systematically …

The Hesperornithiformes (sometimes referred to as Hesperornithes) are the first known birds
to have adapted to a fully aquatic lifestyle, appearing in the fossil record as flightless, foot …

In recent years, avian systematics has been characterized by a diminished reliance on
morphological cladistics of modern taxa, intensive palaeornithogical research stimulated by …

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

Streamlining a body is a major adaptation for aquatic animals to move efficiently in the
water. Whereas diving birds are well known to have streamlined bodies, such body shapes …

Birds are some of the most diverse organisms on Earth, with species inhabiting a wide
variety of niches across every major biome. As such, birds are vital to our understanding of …

The Hesperornithiformes constitute the first known avian lineage to secondarily lose flight in
exchange for the evolution of a highly derived foot-propelled diving lifestyle, thus …

The continental tetrapod assemblages from the Santonian-Maastrichtian of Europe consist
of dinosaurs (theropods: Abelisauroidea, Alvarezsauridae, Dromaeosauridae …

Despite extensive discoveries across the globe over the past two centuries, little
phylogenetic work has been done on the Hesperornithiformes. Spanning the late Early to …

The broad biogeographic distribution of Hesperornis fossils in Late Cretaceous Western
Interior Seaway deposits has prompted questions about whether they endured polar winters …