Probabilistic divergence time estimation without branch lengths: dating the origins of dinosaurs, avian flight and crown birds

Probabilistic divergence time estimation without branch lengths: dating the origins of dinosaurs, avian flight and crown birds

Branch lengths-measured in character changes-are an essential requirement of clock-based divergence estimation, regardless of whether the fossil calibrations used represent nodes or tips. However, a separate set of divergence time approaches are typically used to date palaeontological trees, which may lack such branch lengths. Among these methods, sophisticated probabilistic approaches have rec...

Dating divergence of Polystigma and other Sordariomycetes

Studies on the evolutionary history of ascomycetes in terms of time scale will help to understand historical patterns that shape their biodiversity. Until now most of dating studies of ascomycetes have focused on major events in fungal evolution but not on divergence events within smaller groups of fungi e.g. within Sordariomycetes. We used molecular dating to estimate the time of separation of...

Evolution of olfaction in non-avian theropod dinosaurs and birds.

Little is known about the olfactory capabilities of extinct basal (non-neornithine) birds or the evolutionary changes in olfaction that occurred from non-avian theropods through modern birds. Although modern birds are known to have diverse olfactory capabilities, olfaction is generally considered to have declined during avian evolution as visual and vestibular sensory enhancements occurred in a...

Feathered dinosaurs, flying dinosaurs, crown dinosaurs, and the name “Aves”

The taxon name “Aves” is currently used for several different clades, a situation that violates the fundamental nomenclatural principle that, to minimize ambiguity, each taxon name should refer to a single taxon. To clarify this situation, we explore some general issues concerning the properties of the three classes of phylogenetic definitions, including: how names can be tied to clades through...

Avian Forelimb Muscles and Nonsteady Flight: Can Birds Fly Without Using the Muscles in their Wings?