TAXONOMY AND INTRASPECIFIC VARIATION OF MACROCEPHALITES-FORMOSUS (SOWERBY) FROM THE JURASSIC CHARI FORMATION, KUTCH, WESTERN INDIA

Macrocephalites Zittel, 1884, an important genus in Kutch biostratigra phy, shows considerable diversity at species level. Macrocephalites fo rmosus (Sowerby) is one species which shows a wide range of variabilit y of different morphological characters. A detailed statistical analys is of the principal biocharacters of 140 individuals collected from di fferent localities of Kutch was made to assess quantitatively the rang e of variation of the species. ''Macrocephalites chariensis (Waagen)'' , which was previously designated as a separate species, is demonstrat ed here to be a variant of Macrocephalites formosus and is incorporate d into the latter species. An attempt is made to delineate the generic characters of Macrocephalites and describe the diagnostic characters of the species M. formosus in detail. The variability of the species h as no obvious adaptive significance.