BIOMETRIC STUDY OF LEPIDOCYCLINA (NEPHROLEPIDINA) FROM KUTCH, SAURASHTRA AND QUILON (INDIA)

Abstract

The biometric parameters of Lepidocyclina (Nephrolepidina) from the Oligocene - Early Miocene sections of Kutch, Saurashtra and Quilon are studied to evaluate their biostratigraphic importance Following the biometric concept L. (N.) isolepidinoides is identified in the Early Oligocene sequence of Kutch and L. (N.) sumatrensis from die Early Miocene sections of Kutch, Saurashtra and Quilon. The nephrolepidines of Kutch appear to show a gradual sustained change with interval of arrested evolution. The average value of parameter - A stagnated at about 42% during Oligocene and increased to nearly 46% in Early Miocene times. The value of C increased from 1.7 in Early Oligocene to 2.6 in Late Oligocene and 3.9 in Early Miocene. During this interval F increased from 1.2 to 2.7. The parameters A, C and F are found to be most dependable in inferring the relative age of the nephrolepidine assemblages from the studied localities. The staggering values of E and dc prevent them from a reliable use in biostratigraphy.