Generic distinguishing characteristics and stratigraphic ranges of fossil corallines: An update

Corallines or coralline algae are carbonate secreting and strongly calcified red algae of the order Corallinales of division Rhodophyta. Architecturally, the corallines have two groups, the nongeniculate and geniculate coralline forms. Corallines are used as a potential tool for paleoecology, paleoenvironments and paleobathymetry. Coralline algae are builder of porous and permeable carbonate reservoir rocks for hydrocarbon and reefs rich in hydrocarbon. The old approach, ca. prior to 1977, of taxonomy of fossil coralline genera has been replaced by the modern approach that established during the last decade using certain distinguishing features such as arrangement of basal filaments, cell fusions, conceptacle perforations and orientation of filaments around conceptacles of living corallines. The earliest confirmed fossil record of coralline algae is from the Hauterivian (Early Cretaceous) and from the Hauterivian to the Pleistocene 9 nongeniculate coralline genera, namely Distichoplax, Lithophyllum, Lithoporella, Lithothamnion, Mesophyllum, Neogoniolithon, Phymatolithon, Spongites and Sporolithon and 7 geniculate genera, viz. Amphiroa, Arthrocardia, Calliarthron, Corallina, Jania, Metagoniolithon and Subterraniphyllum having different stratigraphic ranges are unequivocally known as fossils. After 1977, we do not have a comprehensive publication giving the generic distinguishing characteristics and stratigraphic ranges of both nongeniculate and geniculate corallines. The present paper gives an update of distinguishing characteristics of fossil coralline algal genera and their stratigraphic ranges.