Birds are one of the most recognizable and diverse groups of modern vertebrates. Over the
past two decades, a wealth of new fossil discoveries and phylogenetic and …

Background The origin of birds is one of the most enduring and dramatic evolutionary
debates. The hypothesis that the primarily small-sized birds are nested within a theropod …

Dating the tree of life is a core endeavor in evolutionary biology. Rates of evolution are
fundamental to nearly every evolutionary model and process. Rates need dates. There is …

Discoveries of bird-like theropod dinosaurs and basal avialans in recent decades have
helped to put the iconic 'Urvogel'Archaeopteryx into context,,,, and have yielded important …

Archaeopteryx is widely accepted as being the most basal bird, and accordingly it is
regarded as central to understanding avialan origins; however, recent discoveries of derived …

Patagonia has yielded the most comprehensive fossil record of Cretaceous theropods from
Gondwana, consisting of 31 nominal species belonging to singleton taxa and six families …

Ammonites underwent an evolutionary diversification after the mass extinction of the end
Triassic induced by the formation of a Large Igneous province (LIP), and this group provides …

Coelurosauria is the most diverse clade of theropod dinosaurs. Much of this diversity is
present in Paraves—the clade of dinosaurs containing dromaeosaurids, troodontids, and …

For as long as dinosaurs have been known to exist, there has been speculation about their
appearance. Fossil feathers can preserve the morphology of color-imparting melanosomes …

The wings of birds and their closest theropod relatives share a uniform fundamental
architecture, with pinnate flight feathers as the key component,,. Here we report a new …