Foramgeographical affinities of the west and east coasts of India: An approach through cluster analysis and comparison of taxonomical, environmental and ecological parameters of Recent foraminiferal thanatotopes

Abstract

Q-Mode cluster analysis of one hundred sixty species of Recent foraminifera from twenty nine Recent littoral-thanatotopes from 4000 km long coastal-stretch of India reveals that its west and east coasts belong to two separate foramgeographical realms as their assemblages form two separate 'clusters' with only 0.1 level of 'Degree of Association' amongst them. The pattern of clusters shows two faunal assemblages namely- 'Inner' and 'Outer East Marginal Assemblage of Arabian Sea' along the West Coast and similarly two assemblages namely. 'Inner-' and 'Outer West Marginal Assemblage of Bay of Bengal' along the East Coast of India. A taxonomic comparison of one hundred sixty reported species of Recent foraminifers from littoral-thanatotopes of the region shows that only twenty six of them are common to the West and the East Coast of India. A comparison of plots of suborders- Rotaliina, Miliolina and Texturaiina on 'triangular model for environmental and ecological interpretations' also attests to their different affinities.