Revision of the antillocaprinid rudist bivalve Antillosarcolites Chubb with a description of a new genus: Implications for evolution of Antillocaprinidae

The antillocaprinid rudist bivalve Antillosarcolites Chubb is revised based on abundant specimens from the Campanian of Jamaica. Two genera are recognised: Antillosarcolites, type species Antillosarcolites macgillavryi Chubb, and Parantillosarcolites nov. gen., type species Parantillosarcolites lenticularis nov. gen., nov. sp. These two genera are characterised by distinct myocardinal arrangements and differ by the nature of the fill of the sockets for the myophores and additional toothlet. This revision indicates that the Antillocaprinidae were already highly diverse in the middle Campanian.