Studying variation and phenotypic plasticity in the shell shape of Vivipara angularis Muller, a native freshwater species from lakes, has been interesting in order to understand the evolutionary processes in fragile environments. In this study, the population structures of the snails were investigated based on their shell shapes. The snails were collected in Lake Apo in Bukidnon, Lake Wood and Dasay in Zamboanga and Lake Holon, South Cotabato, Philippines. Geometric morphometric tools such as relative warps, superimposition, thin-plate splines and cluster analysis were employed. The results revealed significant variations in shell shapes among V. angularis populations from different lakes. Most variations in the shells were detected in the spire, body whorl and inner lip of the aperture which indicated that the degree of dissimilarity varied from population to population. Meanwhile, Lakes Apo, Dasay and Wood shared the most similarities. Significant differences in shell shapes were observed in lake populations, but what was significant in this study was that the variations could not be attributed to the geographic distances between the lakes but maybe to the ecological and environmental differences between the lakes resulting in the developmental modifications of the shell shapes.
Ober KA, Connolly CT. Geometric morphometrics and phylogenetic analyses of Arizona Sky Island populations of Scaphinotus petersi Roeschke (Coleoptera: Carabidae). Zoological Journal of the Linnean Society, 2015; 175: 107-118.
Dos Reis SF, Duarte LC, Monteiro LR, Von Zuben FJ. Geographic variation in cranial morphology in Thrichomys apereoides (Rodentia: Echimyidae). I. geometric descriptors and patterns of variation in shape. J Mammal., 2002; 83: 333-344.
Avise JC. Phylogeography: the history and formation of species. Cambridge, Harvard University, 2000, p. 447.
Coyne JA, Orr HA. Speciation. Sunderland, MA: Sinauer Associates Inc., 2004.
Cruz RAL, Vallejo BM. Species discrimination in Philippine Oliva Linnaeus 1758 (Gastropoda: Olividae) using size and shape diversity measures. Loyola Schools Review: Science and Engineering Edition, 2009; 8: 85–104.
Adams DC, Rohlf FJ, Slice DC. Geometric morphometrics: ten years of progress following the ‘revolution’. Italian Journal of Zoology, 2004, 71: 5–16.
Lam PKS, Calow P. Differences in the shell shape of Lymnaea peregra (müller) (gastropoda: Pulmonata) from lotic and lentic habitats; environmental or genetic variance? Journal of Molluscan Studies, 1988; 54(2):197-207.
Moneva, C.S., Torres, M.A.J. and Demayo, C.G. Relative Warp and Correlation Analysis based on Distances of the Morphological shell shape patterns among freshwater gastropods (Thiaridae: Cerithimorpha). Aquaculture, Aquarium, Conservation & Legislation International Journal of the Bioflux Society, 2012; 5(3):124-135.
Camama CG, Torres MAJ, Manting MME, Gorospe JG, Demayo CG. Landmark-based geometric analysis in describing the shell of the freshwater gastropod Vivipara angularis (Gastropoda: Viviparidae) from Lake Dapao, Pualas, Lanao del Sur, Mindanao, Philippines. Advances in Environmental Sciences - International Journal of the Bioflux Society, 2014; 6(1): 44-54, 2014.
Rohlf FL. tpsRelw version 1.45. SUNY, Stony Brook, NY, 2007.
Rohlf FL. tpsDig version 2.11. SUNY, Stony Brook, NY, 2008.
Hammer O, Harper DAT, Ryan, PD. Paleontologic Statistics (PAST). http://folk.uio.20/ohammer/past., 2002.
Baab KL. The Impact of superimposition Choice in Geometric Morphometric Approaches to Morphological Integration. Journal of Human Evolution, 2013; 65: 689-692.
Camama CG, Torres MAJ, Manting MME, Gorospe JG, Demayo CG. Variations in shapes in relation to size in four lake populations of Vivipara angularis. Research Journal of Fisheries and Hydrobiology, 2015; 10(14): 169-176.
Dunithan A, Jacquemin SJ, Pyron M. Morphology of Elimia livescens (Mollusca: Pleuroceridae) in Indiana, U.S.A. covaries with environmental variation. American Malacological Bulletin, 2011; 30: 1-7.
Callier V. The structure of morphological variation: Morphometric Analysis of variation in four endemic Lake Tanganyika gastropod species. Honors thesis, Mt.Holyoke College, S. Hadley, MA.2005.