The Use of Geometric Morphometric Analysis in Describing Conchological Differences of Vivipara Angularis from Lake Lanao and Lake Dapao, Mindanao, Philippines Conaida Camama MSU-Malabang Community High School, Philippines [email protected] Sharon Rose Tabugo1, Carlo Stephen Moneva2, and Cesar Demayo3 MSU-Iligan Institute of Technology, Philippines [email protected], [email protected], [email protected] Abstract - It is said that dispersion of a group of organisms can lead to variation in phenotype, resulting from interactions between genetic variations in a population and the environment. The environment determines which variations are more favorable. More favorable traits are thereby passed on to the population as a whole. This study was conducted to investigate variation in shell shape of the freshwater gastropod, Vivipara angularis of Family Viviparidae from Lake Lanao and Lake Dapao in the Province of Lanao del Sur using geometric morphometric methods. Lake Lanao and Lake Dapao are among of the oligotrophic ancient lakes in the world inhabited by viviparid snail. Relative Warp Analysis and Correlation Analysis based on Distances (CORIANDIS) were used to determine shell shape divergence and visualize congruence of multivariate traits among V. angularis populations. Relative warp summarizes the vectors of shape variation within populations while CORIANDIS examines similarities among populations and interpreted in terms of congruence among traits. Results confirmed significant shell variation in the spire length, apertural opening, and apical shapes. Variability in Viviparid shell may signify distinctive genotypes and adaptation to varying environments exhibited by the two lakes. Furthermore, the results clearly indicate the importance of geometric morphometric methods in variation analysis. Keywords - CORIANDIS, Geometric Morphometric Analysis, Lake Dapao, Lake Lanao, Relative Warp Analysis, Viviparidae Remark: The full paper may be found in www.inrit2014.com The Fourth International Congress on Interdisciplinary Research and Development, 30 - 31 May 2014, Thailand 20.1 .