Revision of the Antillocaprinidae Mac Gillavry (Hippuritida, Bivalvia) and their position within the Caprinoidea d’Orbigny

Abstract

The rudist bivalve family Antillocaprinidae Mac Gillavry is revised following a study of nearly all available material in museum collections. Based on differences in their myocardinal arrangements, three subfamilies are recognized: the Titanosarcolitinae nov. subfam., the Antillocaprininae Mac Gillavry, and the Parasarcolitinae nov. subfam. Fifteen genera are described, of which ten are new: Eosarcolites nov. gen., Caenosarcolites nov. gen., Clinocaprina nov. gen., Rotacaprina nov. gen., Rudicaprina nov. gen., Stellacaprina nov. gen., Oligosarcolites nov. gen., Polysarcolites nov. gen., Alencasteria nov. gen., and Sawkinsonia nov. gen. Genera, which are placed in monophyletic radiations, are differentiated on minor differences in myocardinal arrangements, morphotype, and presence or absence of tubes. Six new species are described: Eosarcolites radiatus nov. gen., nov. sp., Caenosarcolites scholaris nov. gen., nov. sp., Rudicaprina planus nov. gen., nov. sp., Sawkinsonia maldonensis nov. gen., nov. sp., Alencasteria macrotubularis nov. gen., nov. sp., and Stellacaprina gunteri nov. gen., nov. sp. Cladistic analysis was performed on selected genera from the Caprinoidea, justifing the division of the Antillocaprinidae into three subfamilies, although extensive paraphyletic groupings exist in the lower part of the strict consensus tree. Weighting myocardinal characters produces a strict consensus tree largely consistent with current subfamily- and family-rank taxonomy, and is consistent with the order of appearance of taxa in the fossil record. The Antillocaprinidae show a major evolutionary radiation reaching a first peak in the middle Campanian, a decline in the late Campanian, and a second peak just before the rudist extinction at the end of the Cretaceous.