Feathers exhibit an extraordinary diversity of shapes, which are used by birds to accomplish
a diverse set of functions. Pennaceous feathers have a double branched morphology that …

Avian feathers are a complex evolutionary novelty characterized by structural diversity and
hierarchical development. Here, I propose a functionally neutral model of the origin and …

We present the first explicit theory of the growth of feather shape, defined as the outline of a
pennaceous feather vane. Based on a reanalysis of data from the literature, we propose that …

The developmental basis of morphological complexity remains a central question in
developmental and evolutionary biology. Feathers provide a unique system to analyze the …

Feathers are considered to be one of the most complex integumentary organs. The diverse
morphology of a feather has made it a popular platform for investigating the cellular and …

The present ultrastructural and immunocytochemical study on the embryonic feathers of the
zebrafinch, an altricial passerine bird, describes cellular differentiation of developing …

This ultrastructural study on the regenerating feathers of quail describes the cellular
organization of the barb ridges responsible for the ramification of adult feathers. Bilateral …

The present study deals with the cell structure and three-dimensional organization of barb
and barbule cells within barb ridges of down feathers and juvenile feathers in the chick …

Asymmetry in flight feather vane width is a major functional innovation associated with the
evolution of flight in the ancestors of birds. However, the developmental and morphological …

Variation among adults reflects variation in basic developmental processes, such as cell
division rate. Partitioning the variation into its developmental components would be a major …