Gill morphology and morphometry of the facultative air‐breathing armoured catfish, <scp> <i>Corydoras paleatus</i> </scp> , in relation on aquatic respiration

The Neotropical armoured catfish Corydoras paleatus is a facultative air-breathing teleost commonly exported as ornamental fish. In this species, air breathing enables it to survive and inhabit freshwater environments with low oxygen levels. Therefore, important analyse the gills from morphological aspect its dimensions in relation body mass reference aquatic respiration. For that, were analysed using stereoscopic microscope for morphometric studies, structural ultrastructural studies carried out compare four branchial arches. Furthermore, two immunohistochemical techniques used locate identify presence of Na+/K+ pump. characterization potential cell proliferation organ was assessed an anti-PCNA antibody. results show that C. present some characteristics related diet lifestyle, such limited development gill rakers abundance taste buds. addition, other special features associated environment bimodal observed: scarce absent mucous cells (MCs) filaments lamellae, respectively, localization mitochondria-rich (MRCs) covering basal third which reduces respiratory area. A peculiar finding epithelium mononuclear sarcomeres similar myoid cells, whose functional importance should be determined future studies. Finally, paleatus, interlamellar space site turnover ionoregulation; latter function also performed by lamellae.