On The Buchotrigoniidae (Cretaceous Trigoniida), Their Palaeobiogeography, Evolution And Classification

The content, distribution, evolution and classification of the Cretaceous trigoniid family Buchotrigoniidae are assessed. The evolution of the group is tracked from its first appearance in the late Berriasian of Colombia until its final demise in the early Maastrichtian of Chile. Buchotrigoniids are a provincial group with their greatest diversity and longevity in the Andean Province. From there they spread northwards into the American Province during the Aptian and, simultaneously, migrated eastwards into western Tethys, reaching Central Asia by the late Cenomanian. The origin of the group remains problematical, and the long-held relationship with Syrotrigoniinae is regarded unproven. Due to a lack of beaded escutcheon and median carinae at any growth stage, Buchotrigoniidae are transferred from Myophorelloidea to Megatrigonioidea. As a result of phylogenetic analysis four genera are recognized, two of which are new.