Taxonomic revision of the Late Cretaceous Pectinid Bivalves Neithea (Drouet) and Plicatula (Lamarck) from the Trichinopoly Group, Cauvery Basin, South India

摘要

The two bivalve genera Neithea and Plicatula (family Pectinidae) are all together represented by ten species in the present collection from the Late Cretaceous (Turonian - Coniacian) sediments of the Kulakkalnattam and Anaipadi formations of Trichinopoly Group, Cauvery Basin, south India. The genus Neithea consists of five species, namely Neithea (Neithea) coquandi, Neithea (Neithea) quinquecostata, Neithea (Neithea) aff. gibbosa, Neithea cf. sexcostata, and Neithea (Neithella) notabilis. Similarly, the genus Plicatula also comprises five species namely Plicatula (Plicatula) ferryi, Plicatula (Plicatula) hirsute, Plicatula (Plicatula) multicostata, Plicatula batnesis and Plicatula instabilis. Out of these, Neithea (Neithea) coquandi, Neithea (Neithella) notabilis, Plicatula (Plicatula) ferryi, and Plicatula (Plicatula) hirsute are a new record from the Cauvery Basin. All these ten species have been systematically described here. Most of these bivalve species are cosmopolitan in occurrence and in turn may be quite helpful in understanding the global palaeobiogeography during Turonian-Coniacian interval.