Summary

The localized distribution in morphospace of groups of species assigned to some of the genera established by subdivision of Fenestella s.l. lends weight to the recognition of the recently named genera as morphological characterizable groups. This coherent clustering does not demonstrate that the genera as currently recognized are phylogenetically determined entities but instead adds a new dimension to the argument that they are morphologically coherent, which is consistent with the hypothesis that they are distinct clades. Where data from species assigned to one of the genera are organized into two distinct clouds, an opportunity is provided to evaluate the reason for the gap, which involves the possibilities that inclusion of additional species in the genus would have closed the gap, that one or more species has been misassigned to genus and belongs to a different named genus, or that one of the disjoint sections of the cloud may represent an as yet unnamed genus. In addition, correspondence in the morphospace of genera with subtle putative differences (such as for Spinofenestella and Alternifenestella), invites reconsideration of whether or not the two are indeed different or should be considered as a single genus.

Although the methodology of evaluating a priori generic assignments based largely on characters other than the ones used in original diagnoses provides insights, we do not advocate that exterior characters from this study be used alone as criteria for the recognition of biserial fenestellid Bryozoa genera.