Cladistic analysis of the Paleozoic bryozoan family Monticuliporidae and Mesotrypidae

A set of 127 binary and multistate characters, weighted by the number of derived character states, degree of covariation, and level of homoplasy, was used in a cladistic analysis of type species representing12 genera previously assigned to families Monticuliporidae and Mesotrypidae. The most parsimonious tree consisted of a 10-genus monophyletic crown group with the remaining two genera forming a basal paraphyletic stem group. The composition of the monticuliporid crown group is broadly similar to two earlier classifications (Astrova 1978; Marintsch 1998) while stem group membership matches that of Astrova's (1965, 1978) family Mesotrypidae. Phenetic groupings, based on overall morphological similarity, have memberships that are similar to those of clades but provide no means of determining the polarity of evolutionary relationships either within or between them. Finally, only the observed stratigraphic ranges of the type species of genera provide a statistically significant match with ...