Living out of water: morphological and peptidomic plasticity of gills and skin of Atlantirivulus santensis (Cyprinodontiformes: Rivulidae) during exposure to air

• Grant number: 23/16949-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2024
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Physiology - Compared Physiology
• Principal Investigator: Rafael Mendonça Duarte
• Grantee: Júlia Santana Oliveira
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

Less than 90 species of freshwater fish display an "amphibious" lifestyle, which is characterized by the ability to emerge and spend certain periods out of the water, as a normal part of their life history. Among these fishes, several species of the Rivulidae family (Cyprinodontiformes) stand out, which are highly tolerant to exposure to air and present a great plasticity of behavioral, morpho-physiological and biochemical responses, particularly on gill and cutaneous properties that directly contribute to the homeostasis maintenance during emersion. The species Atlantirivulus santensis is a rivulidae endemic to the Rio Preto sub-basin in the Coastal Plain of the Central-South Coast of São Paulo State (Itanhaém/SP), which inhabits the marginal region of streams, and temporary ponds that are characterized by their extreme environmental conditions, such as hypoxia, low pH and high concentration of dissolved organic carbon. However, the tolerance and physiological adjustments of A. santensis, associated with its tolerance to air exposure, have not yet been studied. Therefore, this work aims to analyze the role of gills and skin in the tolerance of A. santensis during exposure to air. To this end, the survival rate after emersion and changes in the morphology of both gill and skin epithelium will be measured, as well as identifying the profile of peptides in the gills and skin. Thus, we pretend contribute to the understanding of the physiological mechanisms that allowed A. santensis to establish their amphibious lifestyle, and that help the species to colonize new temporary environments with environmental conditions that are highly challenging to maintain homeostasis.