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[Spur development in chick embryos]
Arkhiv Anatomii, Gistologii I Embriologii
|April 1, 1979
Summary
This study details the embryonic development of avian spurs and scales. It reveals that spur evolution from scales involves adding new developmental stages to existing morphogenesis.
Area of Science:
- Embryology
- Developmental Biology
- Comparative Anatomy
Context:
- The development of avian spurs and horny squamae is crucial for understanding evolutionary transformations.
- Histological analysis of tarsometatarsus skin in 8-16-day-old embryos provides insight into early developmental stages.
Purpose:
- To investigate the normal development of spurs and horny squamae in avian embryos.
- To compare the morphogenesis of spurs and squamae to understand phylogenetic transformations.
Summary:
- Spur development involves three stages: initial formation of the horny cover, spur body, and fibrovascular cushion; vigorous growth of the spur germ; and post-hatching bony core formation in males.
- Horny squama morphogenesis occurs in two stages: initial formation of the squamous papilla and horny shell without a fibrovascular cushion, followed by growth of all germ parts.
- Phylogenetic transformation of squama into spurs is achieved by adding new developmental features to the terminal stages of squama morphogenesis.
Impact:
- Provides a detailed histological account of spur and squama development in avian embryos.
- Offers insights into the evolutionary mechanisms driving the transformation of scales into spurs.
- Establishes a comparative framework for studying vertebrate appendage evolution.