Anatomical features of the syrinx in sea gulls

Abstract

The syrinx of four sea gulls (Larus spp.) weighing 395-520 g were examined. The syrinx was a tracheobronchial type formed by the bronchosyringeal cartilages (cartilagines bronchosyringeales) and the tracheosyringeal cartilages (cartilagines tracheosyringeales). Five tracheosyringeal cartilages were fused completely and shaped tympanum. Bronchosyringeal cartilages were formed from 7-C shaped cartilage rings. Lateral and medial tympaniform membrane's which are important for vocalization were observed. The lateral tympaniform membrane was observed between 1st and 2nd cartilage rings of bronchosyringeales. Medial tympaniform membrane was placed between the pessulus and 7th bronchosyringeal cartilages. The interbronchial ligament (ligamentum interbronchiale) connects the left and right primary bronchi at the terminal part of the medial tympaniform membrane. Foramen interbronchiale was situated between the medial tympaniform membrane, pessulus and interbronchial ligament. The tracheolateral muscle (m. tracheolateralis) was attached to the 1st bronchosyringeal cartilages. Similarities and differences of syrinx between sea gulls and other avian species were determined in this study.