CAJ | 학술논문

The Kutch Basin of western India is famous for its rich assemblages of the Callovian-Oxfordian ammonites. The family Oppelidae Douvillé is the second most diverse ammonite group after perisphinctids during the Middle-Upper Jurassic. Hecticoceratinae is the most diverse subfamily within Oppelidae and has wide palaeobiogeographic (near cos-mopolitan) and temporal distributions (Bathonian-Oxfordian). Some species were well time-diagnostic and thus help in interprovincial correlation. The taxonomy of the subfamily Hec-ticoceratinae of Kutch was in a state of lfux until recently. It was not revised since Spath’s (1927-1933) great contribution. Many genera and species were morphogenera or morphos-pecies and they again suffer from excessive subjective splitting. It was therefore badly needed for a comprehensive taxonomic revision of the subfamily with modern aspects of systematics i.e., sexual dimorphism and population dynamics. A lithostratigraphic framework has already been well documented in the Kutch Basin of western India. A high resolution biostratigraphy incorporating stage-intrastage fossil assemblages have been used in interbasinal correlation based on the Callovian-Oxfordian hecticoceratins. Near cosmopolitan distribution of many hecticoceratin genera were widely used for biostratigraphic zonation as well as an understand-ing of the palaeobiogeographic pattern. The phylogeny of the subfamily Hecticoceratinae has been used to construct the cladograms depicting area relationships among different provinces during the Callovian-Oxfordian.