Turtles (Order Testudines) are a unique group of vertebrate animals whose bodies are enclosedinside a bony shell covered in protective scales or scutes. Over the past 220 million years, turtles have diversified from a terrestrial ancestor into aquatic, semi-aquatic, and marine habitats, today occurring on most continents, oceans, and some islands. Despite their roles as indicators of environmental quality, over half of the ~360 living turtle and tortoise species are threatened with extinction by human activities, including habitat degradation, pollution, and overexploitation. My project aims to monitor turtle health based on fluctuating asymmetry (FA), defined as random deviations in the correspondence of left-right bilateral traits. FA is known to arise through developmental disturbance, offering a sensitive biomarker to environmental stress that can lead to shell deformation.

While environmental factors are difficult to detect in preserved specimens, the first chapter of my PhD thesis results suggest that minimum level of FA in total shape, carapace and plastron, indicating that museum collections may be biased towards “ideal” turtle specimens. This suggests the importance of understanding the effect of environmental on living turtle populations shell shape. Also, highly significant Directional asymmetry (DA) suggests that Testudines tend to walk faster using their preferred side. Lateralities have been previously documented in turtles living in aquatic, and terrestrial. My study on museum specimens confirms that whole shell, carapace and plastron of 12 families in order Testudines shows highly significant DA and significance of FA.

In my second chapter I aim to have a descriptive study on the ontogenic allometry of Melanochelys trijuga, where we understand the changes in scute patterns in 128 individuals scanned live using Artec space spider. This study will examine the developmental trajectories of shell scute patterns across different age cohorts, employing advanced geometric morphometric techniques to quantify and characterize shape transformations during the species' developmental progression. By meticulously documenting morphological changes, I aim to establish a robust baseline understanding of natural developmental variations in Indian pond turtle shell shape. Furthermore, this study will explore potential environmental influences on turtle morphological plasticity, potentially elucidating the intricate relationships between developmental processes and ecological effects.

The third chapter will be correlating different environmental and individual health factors with fluctuating asymmetry of ontogenic Melanochelys trijuga landmark data. I will explore between environmental stressors, individual physiological parameters, and fluctuating asymmetry (FA) in ontogenetic Melanochelys trijuga populations. This multifaceted approach of integrating biomechanical, ecological, and physiological perspectives to comprehensively evaluate how environmental conditions potentially modulate developmental symmetry, with particular emphasis on understanding the complex relationships between asymmetry patterns and organismal fitness.

The fourth chapter will be a citizen science project about measuring the presence and abundance of invasive and native Indian freshwater turtles by water eDNA method. Species-specific primers will help to identify 6 Indian freshwater turtles and if there is co-existence with red-eared slider and invasive turtle. This research will help a critical intervention in conservation biology, potentially informing evidence-based policy interventions regarding invasive species management, wildlife trade regulations, and ecosystem preservation strategies. Moreover, the integrated citizen science methodology not only generates rigorous scientific data but simultaneously serves as an innovative environmental education platform, fostering public engagement, and ecological awareness.Together, these four chapters will contribute significantly to the knowledge of turtle biology and provide critical information for the conservation of these ecologically important species. By integrating morphological study and environmental DNA surveys, my dissertation aims to understand factors influencing freshwater turtle populations and inform conservation strategies aimed at preserving their populations, both in India and globally.