Biophysical mechanisms of morphogenesis in lizard lungs

Area of Science:

• Comparative developmental biology
• Evolutionary morphology
• Vertebrate embryology

Background:

• Squamate reptile lungs (lizards and snakes) display remarkable diversity in structure, from simple sacs to complex chambered organs with diverticulae.
• Embryonic lung development in anoles involves stress ball morphogenesis, where luminal fluid pressure drives epithelial protrusion through a smooth muscle mesh.

Purpose of the Study:

• To investigate the conservation of stress ball morphogenesis in embryonic lung development across different squamate species.
• To elucidate the physical mechanisms underlying the formation of transitional chambers and diverticulae in squamate lungs.

Main Methods:

• Comparative analysis of embryonic lung development in brown anoles, leopard geckos, and veiled chameleons.
• Experimental manipulation and computational modeling to understand morphogenetic processes.
• Histological examination of lung tissue during embryonic development.

Main Results:

• Epithelial protrusion through a pulmonary smooth muscle mesh is conserved across the studied squamate species.
• Luminal inflation is not universally conserved; leopard geckos and veiled chameleons utilize epithelial folding and proliferation.
• Transitional chambers and diverticulae in veiled chameleons develop via apical constriction, a mechanism also seen in avian lung airway branching.

Conclusions:

• Distinct morphogenetic mechanisms contribute to the diverse epithelial structures observed in squamate lungs.
• These varied developmental pathways likely play a role in the species-specific physiological and ecological adaptations of lizards and snakes.