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Statolith comparison of two south-west Atlantic Loliginid squid: Loligo sanpaulensis and loligo gahi
Abstract
The statoliths of two South-West Atlantic loliginid squid, Loligo gahi and Loligo sanpaulensis, were studied to determine if they could be a useful tool for species differentiation. Allometric equations were employed to
examine differences in statolith shape and growth. Statolith dimensions were standardized by total length and dome length and principal components analysis was employed to compare the shapes. The first component was used as a discriminant function to classify species. There is clear species differentiation in both size and shape of the statoliths. The statoliths of Loligo gahi are significantly larger than those of Loligo sanpaulensis. Loligo gahi statoliths are characterized by the presence of a prominent dorsal dome and a relatively long, thin rostrum, whereas those of Loligo sanpaulensis have a rounded dome and short rostrum. The discriminant function correctly separated 92.9% of Loligo gahi and 88.5% of Loligo sanpaulensis statoliths in additional samples. Relationships between mantle length and statolith length and between total mass and statolith length were determined for both species.
examine differences in statolith shape and growth. Statolith dimensions were standardized by total length and dome length and principal components analysis was employed to compare the shapes. The first component was used as a discriminant function to classify species. There is clear species differentiation in both size and shape of the statoliths. The statoliths of Loligo gahi are significantly larger than those of Loligo sanpaulensis. Loligo gahi statoliths are characterized by the presence of a prominent dorsal dome and a relatively long, thin rostrum, whereas those of Loligo sanpaulensis have a rounded dome and short rostrum. The discriminant function correctly separated 92.9% of Loligo gahi and 88.5% of Loligo sanpaulensis statoliths in additional samples. Relationships between mantle length and statolith length and between total mass and statolith length were determined for both species.
