Morphometric evaluation of some shell characteristics of Philippine native and gold apple snails
2002
Pagulayan, R.C. (Philippines Univ. Los Banos, College, Laguna (Philippines). Inst. of Biology) Joshi, R.C.
The following morphometric characteristics were taken from 99 individuals of the golden apple snail, Pomacea canaliculata and the native apple snail Pila conica: shell length (SL), shell width (SW), body whole length (BWL), aperture length (AL), aperture width (AW), shell thickness (ST), operculum thickness (OT), spire height (SpH), shell weight (SWe), body weight (BWe), and operculum weight (OWe). Cluster analysis of the 11 characters failed to delineate P. canaliculata and P. conica. Neither was it able to delineate the males from the females. Principal factor analysis a probable 2-factor character groups using factor loadings of 0.4 and more or -0.4 or less. The first factor appears to indicate the shape of the whole shell (shell length, shell width, body whorl length and aperture length). The second factor is indicated by operculum character (thickness and weight) and spire height. PCA analyses appear to agree with the general "naked eye" observation of using operculum characteristics to delineate the two species. It is however, difficult to distinguish sex in P. conica based on shells
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