Developmental Patterns and the Identification of Homologies in the Avian Hand

1997/10/24 by Ann C. Burke, Alan Feduccia · 5 citations
Earth and Planetary Sciences · Mathematics · Environmental Science · #Paleontology and Evolutionary Biology #Morphological variations and asymmetry #Avian ecology and behavior

paper · doi:10.1126/science.278.5338.666

openalex publication_date 1997/10/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23

Abstract

Homologies of digits in the avian hand have been debated for 150 years. Cladistic analysis nests birds with theropod dinosaurs. Theropod hands retain only digits I-II-III, so digits of the modern bird hand are often identified as I-II-III. Study of the developing manus and pes in amniote embryos, including a variety of avian species, shows stereotyped patterns of cartilage condensations. A primary axis of cartilage condensation is visible in all species that runs through the humerus into digit IV. Comparison to serially homologous elements of the hindlimb indicates that the retained digits of the avian hand are II-III-IV.

Citations

• Fossils, genes and the evolution of animal limbs
• Early Adaptive Radiation of Birds: Evidence from Fossils from Northeastern China

Cited by

• The Theropod Ancestry of Birds: New Evidence from the Late Cretaceous of Madagascar
• Counting the Fingers of Birds and Dinosaurs
• 1,2,3 = 2,3,4: A solution to the problem of the homology of the digits in the avian hand
• Bird flight [wikipedia]
• Origin of birds [wikipedia]