Sonarina tamilensis n. gen., n. sp., an unusual cheilostome bryozoan from the Late Cretaceous of southern India

The Ariyalur Group of Tamil Nadu and Pondicherry in southern India contains a rich bryozoan fauna of 100 species, including an unusual cheilostome from the Upper Campanian or Lower Maastrichtian Kallankurichchi Formation originally identified as Macropora? sp. If the generic attribution were to be correct for this bryozoan, it would considerably antedate the oldest known example of Macropora, which is from the early Eocene. Here we formally describe this un-named Ariyalur Group bryozoan as Sonarina tamilensis gen. et sp. nov., showing that it is not closely related to Macropora (family Macroporidae) but instead may be accommodated in the family Onychocellidae. The patterning of hexagonal ridges on the frontal walls of Sonarina resembles that found in some unrelated cheilostome species and can be interpreted as the most efficient pattern for strengthening the frontal wall.