The Miocene (Burdigalian) Operculinids of Channa Kodi, Padappakkara, Kerala, Southern India

An Operculina assemblage collected from the fossiliferous Quilon Limestone in SW India (Padappakkara locality) is described here. The Operculina assemblage is characterized by very high abundance, excellent preservation and relatively high diversity. 61 specimens have been investigated by computed tomography: this allowed the measurements of a number of biometric parameters obtained on equatorial and axial sections of the specimens as well as abundant information on the external ornamentation of each test. The biometrical parameters measured on each specimen are as follows: maximum diameter of the shell, maximum thickness of the shell, proloculus diameter, number of chambers in the first, second and last whorl, height of the last complete chamber, height of the last chamber of the penultimate whorl, keel thickness and ornamentation type. The combination of such a large number of biometric parameters measured on each single specimen, allowed the visualization by statistical analyses of the real differentiation among the investigated taxa. Five species have been therefore recognized: O. malabarica, O bartschi, O. ammonoides, O. lawrieana, and O. granulosa.