COMPARATIVE ANALYSIS OF THE CARDIORESPIRATORY SYSTEM IN ANURANS

• Grant number: 23/16747-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: September 01, 2024
• End date: February 29, 2028
• Field of knowledge: Biological Sciences - Morphology - Anatomy
• Principal Investigator: Luis Felipe de Toledo Ramos Pereira
• Grantee: Andres Santiago Carrasco Medina
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 22/11096-8 - From the natural history to the conservation of Brazilian amphibinas, AP.TEM

Abstract

The heart of anurans has five chambers: venous sinus, left and right atria, ventricle, and arterial cone. However, in a recent study, it was observed that individuals of Brachycephalus rotenbergae and B. pitanga have a heart with a reduced atrial septum, thus, with one less chamber. Furthermore, it was noted that they lack a visible carotid body, which is found in the carotid artery and possibly contributes to blood pressure regulation. Therefore, we decided to study the internal morphology of selected anuran species to test the hypothesis that these characteristics observed in B. rotenbergae and B. pitanga are synapomorphies of the genus Brachycephalus, or of a more restricted clade, and if there is a correlation between the reduction of the atrial septum and the absence of the carotid body. To do so, we will describe the cardiorespiratory system of the target species through dissections and histology. Subsequently, character states will be plotted on current phylogenies to test our hypotheses. In addition, we will perform dissections on small-sized anuran species without miniaturization and others with miniaturization to determine if the reduction of the atrial septum and the absence of the carotid body are present only in miniaturized species. Species inhabiting different environments (aquatic, semi-aquatic, and terrestrial) will also be selected to test the hypothesis that the internal heart morphology is determined by habitat, which may be related to different degrees of cutaneous and pulmonary respiration (which, consequently, would affect the circulatory system). Thus, in this project, we will explore morphological aspects of the cardiorespiratory system of anurans and test hypotheses with historical and ecological context.