Biometry of early Oligocene Lepidocyclina from Kutch, India

Abstract

Lepidocyclina is represented by its two subgenera, Eulepidina and Nephrolepidina, in the Early Oligocene sequence of Kutch. Biometrically, significant distinction exists between the two subgenera whose taxonomic status has been questioned by some previous workers. Q-mode cluster analysis classifies the assemblage into two groups conforming to conventional classification. The variation in biometric parameters is explained by R-mode factor analysis with rotation by varimax criterion. II suggests that size of embryonic chambers,grade of enclosure and curvature of the common wall together explain the maximum variance in lepidocyclines. It implies the taxonomic importance of these features. A linear discriminant function is proposed to distinguish the two subgenera. It will be especially useful in those cases where peri-embryonic chambers are not visible in section. In view of stasis of some biometric parameters, their temporal variations should be ascertained before they are used in taxonomy or dating. A properly selected combination of parameters rather than single parameters should be used for such studies.