International network for natural sciences – research journal
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Relative Warp Analysis on Shell Shapes of Faunus ater in Guihing River Hagonoy, Davao del Sur

By: Darlene Deanne C. Mallari, Bianca T. Rabang, Renante V. Mesias, Von Jezzrel A. Jumao-as, Mark Anthony J. Torres, Elani A. Requieron

Key Words: Pachychilidae, Oviparous, Shell morphology, Geometric morphometric.

J. Bio. Env. Sci. 8(3), 55-63, March 2016.


This study aims to characterize the relative warp analysis on shell shapes of the Faunus ater. A total of 60 individuals were analyzed based on their shell shape and was deliberated using a landmark-based methodology. The following are the total landmarks stated and used: ventral/aperture=27, dorsal=17 and top of the whorl=147. Procrustes ANOVA showed the significant level of symmetry of F. ater on its ventral/aperture=0.0392123; dorsal=0.1069 and top of the whorl=1.20366 portion. To further sustain the analysis, the upper five percent (5%) value of PCA was performed to visualized shape variation landmarked subject together with the histogram, and also used to investigate patterns of variation in the positions of landmarks: ventral/aperture=100.00%; dorsal=16.67% and top of the whorl=96.702%. The designated relative warps by its overall shape variation and percentage variance of F. ater confirms (a)16.66671667%; (b)16.6666%; (c)20.0001% for (a)ventral/aperture, (b)dorsal and (c)top of the whorl courtesy of relative warp box plot and histograms. The results of this study suggest that Relative Warp Analysis (RWA), Principal Component Analysis (PCA) of F. ater species mostly differ in the latter part and their body depth. The study of morphological differences in sizes and pattern using the ventral/aperture, dorsal, and top of the whorl characteristics of the shell clearly indicates its shell shape variation. In this manner, F. ater was quantitatively defined.


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