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Title Relative Warp and Correlation Analysis based on Distances of the Morphological shell shape patterns among freshwater gastropods (Thiaridae: Cerithimorpha)
Posted by Carlo Stephen Moneva
Authors Carlo Stephen O. Moneva, Mark Anthony J. Torres, Cesar G. Demayo
Publication date 2012/6/19
Journal Aquaculture, Aquarium, Conservation & Legislation BIOFLUX
Volume 5
Issue 3
Pages 124-135
Publisher International Journal of the Bioflux Society
Abstract Shell morphology has various details in their architecture that contributes effectively to gastropod identification and classification. A conventional approach has been made to study shell morphology using descriptions of biological shapes. However, descriptions can be strengthened by applying additional quantitative tools. Relative Warp Analysis and Correlation Analysis based on Distances (CORIANDIS) were used to determine shell shape divergence and ascertain factors associated with the shell shape variation in three species of the genus Melanoides of the family Thiaridae namely, Melanoides granifera, Melanoides maculata, and unknown Melanoides species belonging to the family Thiaridae. Relative warp summarizes the vectors of shape variation within samples. CORIANDIS on the other hand, examines similarities among samples and interpreted in terms of congruence among traits. Results of the relative warp analysis showed significant shell shape variation among the Thiaridae species in the height of the spire, aperture, and apical shapes. Distance matrices were also constructed for the three data sets of shell characters: ventral/aperture, dorsal, and top/whorl shell. Results of the comparison via correlation analyses of distances among the species showed that an unknown Melanoides species is closely related to M. maculata than M. granifera. The results of the present study clearly show the importance of geometric morphometric analysis determination of systematic relationship in Thiarid snails.
Index terms / Keywords Relative Warp Analysis, CORIANDIS, shell shape, Thiaridae, shell characters.