Sexual dimorphism in digit lengths: relationships with gonadal development, reproductive strategies and altitudinal gradients

• Grant number: 21/14152-3
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: March 01, 2022
• End date: August 31, 2022
• Field of knowledge: Biological Sciences - Zoology - Morphology of Recent Groups
• Principal Investigator: Tiana Kohlsdorf
• Grantee: Ana Paula Cipriano
• Supervisor: Joao Francisco Botelho
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: Pontificia Universidad Católica de Chile, Chile
• Associated to the scholarship: 20/10330-1 - Sexual dimorphism in digit ratio in Tropidurus catalanensis: relations to climatic parameters, BP.MS

Abstract

Occupation of different environments by a given species may occur in association with changes in developmental processes and result in morphological variation among populations. One morphological trait of particular interest in this scenario is the digit length, a characteristic that is sexually dimorphic in some lineages and is assumed as a proxy of mechanisms during embryo development that are integrated through the sensitivity to steroid hormones. Although digit length is considered a prenatal marker of sex hormones concentrations, it remains obscure if the timing of gonadal formation matches the embryonic stages when sexual dimorphism (SD) is established in the digits. The current BEPE proposal consists of a six-month internship under supervision of Dr. João Francisco Botelho at the Facultad de Ciencias Biológicas - Pontificia Universidad Católica de Chile, to develop two complementary conceptual units. The first unit is directly related to the approach already used in the main Master project to evaluate morphological variation along environmental gradients, and aims to evaluate dimorphic patterns of digit ratios in Liolaemus lizards distributed in an altitudinal gradient; in this unit, we intend to include species that differ in reproductive strategies (i.e oviparity-viviparity continuum). The second unit aims to evaluate synchronic events in gonadal development and the establishment of SD in digit length through the analyses of embryos in different stages. These complementary units during the BEPE represent an innovative approach for studying SD evolution in digit lengths that integrates ecological aspects, reproductive strategies, and timing of developmental events.