Biostratigraphy and taxonomy of the rudist Chiapasella in the Titanosarcolites Limestones (Maastrichtian) of Jamaica

The taxonomy of the radiolitid rudist Chiapasella Müllerried from theTitanosarcolites Limestones of Jamaica is revised based on the bed-by-bed collection of specimens from the Central and Maldon inliers. Two species are recognised: Chiapasella radiolitiformis Trechmann and C. trechmanni sp. nov.C. radiolitiformis is characterised by usually one or more costae (two or more infolds) in the interband, by the relatively narrow ventral band Vb, and by a costal ornamentation of strong growth lines and subsidiary vertical striations. C. trechmanni is characterised by the usual presence of no costae (one infold) in the interband, by the relatively wide Vb, and by a costal ornamentation dominated by vertical striations rather than horizontal growth lines. Two zones are recognised in theTitanosarcolites Limestones, a lower zone with C. radiolitiformis (B and Middle C Beds of the Central Inlier) and an upper zone with C. trechmanni (D and lower F Beds of the Central Inlier; Maldon Limestone, Popkin Shales and Vaughansfield Limestone of the Maldon Inlier).