A Mesozoic bird from Gondwana preserving feathers.

Area of Science:

• Paleontology
• Evolutionary Biology
• Avian Paleontology

Background:

• Mesozoic bird fossils from Gondwana are scarce and lack feather detail.
• Previous knowledge of rachis-dominated feathers was limited to 2D impressions.

Purpose of the Study:

• To describe a new fossil bird specimen from Early Cretaceous Gondwana (NE Brazil).
• To elucidate the 3D structure and homology of rachis-dominated feathers.
• To investigate the paleobiogeography of early bird feather types.

Main Methods:

• Description of a fossil bird skeleton with associated feathers.
• Analysis of feather morphology, including the rachis and rectrices.
• Comparative analysis with modern bird feathering and other fossil taxa.

Main Results:

• A well-preserved fossil bird skeleton with feathers from NE Brazil.
• Detailed 3D structure of rachis-dominated feathers, identifying the scapus as the robust, elliptical rachis.
• Rectrices show a row of rounded spots, suggesting original coloration.
• Juvenile tail plumage resembles that of modern adult birds.

Conclusions:

• The fossil provides crucial insights into the 3D structure and homology of rachis-dominated feathers.
• The discovery extends the paleobiogeographic range of this feather morphotype to South America.
• This finding broadens our understanding of basal bird evolution and feather diversity in Gondwana.