Article: Phylogeny of Orbirhynchia Pettitt, 1954 (Brachiopoda, Rhynchonellida)
A computer-based parsimony analysis of the brachiopod genus Orbirhynchia (Late Albian-Middle Campanian) is described. The resulting cladogram indicates that the genus divided into two distinct lineages soon after its appearance in the Late Albian. One group is known only from marly and sandy facies of Cenomanian age, while the second, more diverse, group appeared later in the Cenomanian but persisted into the Campanian. These two groups exhibit distinct morphological trends which may be related to different ecological niches, perhaps with respect to local sedimentary environment.