Article: A new cheilostome bryozoan from the Cretaceous of India and Europe: a cyclostome homeomorph
The new ' malacostegan' cheilostome Chiplonkarina is an unusual genus previously misidentified as a cerioporine cyclostome because of extreme homeomorphy in both zooid-level and colony-level morphology. The type species, C. dimorphopora, is the dominant bryozoan in west-central India in the mid-Cretaceous Bagh Group, whose geology is briefly reviewed, and is recorded here for the first time in the Cenomanian of France. A second species, C. bretoni sp. nov., occurs in the Lower Cenomanian of France and Germany. In common with many free-walled cyclostomes (and other stenolaemates), the zooids of Chiplonkarina are long and tubular, and branches of the dendroid colonies have axial endozones with zooids orientated parallel to the direction of branch extension, bending through almost 90° into the surrounding exozone, where zooids are oriented perpendicular to the branch surface such that their lengthening caused branches to thicken. However, the presence of a cuticular layer in the interzooidal walls, fibrous wall microstructure, and the morphology of the colony base and overgrowths demonstrate that Chiplonkarina is a cheilostome. Chiplonkarina can be viewed as an early cheilostome' experiment' in erect growth using a typically stenolaematous growth pattern seldom repeated by the numerous erect cheilostomes that evolved subsequently. The presence of Chiplonkarina in the Nilkanth Formation ('Upper Tal Shell Limestone') of Uttar Pradesh, India supports the correlation of these deposits with the Bagh Group and implies a likely Cenomanian-Turonian age.