title: The origin of the Pycnodonteinae and relationship between gryphaeas and true pycnodontes
abstract: Berriasian (Early Cretaceous) oyster Pycnogryphaea weberae from Crimea is one of the earliest known pycnodonteine oysters. Examination of shell morphology and microstructure of this species shows that it shares characters of the subfamilies Gryphaeinae and Pycnodonteinae. Shell microstructure of Pycnogryphaea weberae lacks vesicular structure and is similar to microstructure of the genus Gryphaea. At the same time the shell of this species possesses morphological characters typical of pycnodonte
journal: Acta Palaeontologica Polonica