Systematics of the bryozoan genus Macropora (Cheilostomata)

Abstract

Macropora is a distinctive genus of anascan cheilostomes. All species have large zooids with an extensive cryptocystal frontal shield perforated by numerous pores through which parietal muscle strands pass. Also characteristic of Macropora are the calcified opercula closing the d-shaped orifice, avicularia resembling autozooids but having slightly enlarged, typically crenulated opercula/mandibles, and large ovicells that are often costate. This mostly Australasian genus has a documented fossil record stretching back to the Eocene. Here we revise the generic diagnosis of Macropora and describe eight new species from New Zealand (three Recent: M. nodulosa sp. nov., M. filifera sp. nov. and M. carlosi sp. nov.; five fossil: M. septispinosa sp. nov., M. similis sp. nov., M. pittensis sp. nov., M. leeae sp. nov. and M. bullata sp. nov.) and one new species from Japan (M. mawatariorum sp. nov.), the only species known with certainty to occur in the northern hemisphere. New observations are given for some previously described species, several of which are illustrated using SEM for the first time. The northern hemisphere Upper Cretaceous species Monoporella exsculpta (Marsson), showing features allowing it to be placed tentatively in the stem-group of Macropora, is redescribed. Attempts to resolve the phylogenetic relationships of species within Macropora were hampered by the relatively few morphological characters compared with the number of species, and it proved impossible to obtain a phylogeny robust to slight changes in taxon and/or character inclusion. The favoured cladogram has poor bootstrap and Bremer support, and its stratigraphical and biogeographical congruences are low. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153, 115–146.