© The Norwegian Academy of Science and Letters • Zoologica Scripta, 29, 3, July 2000, pp247–264 247 Grischenko, A. V., Mawatari, S. F. & Taylor, P. D. (2000). Systematics and phylogeny of the cheilostome bryozoan Doryporella. — Zoologica Scripta, 29, 247–264. The four nominal species of the Arctic-Boreal anascan bryozoan Doryporella Norman are revised. Colonies of Doryporella are small, typically encrust shells and pebbles, and have autozooids with frontal walls bearing a distinctive reticulate pattern of polygonal ridges. High resolution SEM shows the frontal wall to be an interior wall (cryptocyst), contrary to previous studies which have regarded it as an exterior wall (gymnocyst). The inter-relationships between the species assigned to Doryporella are assessed cladistically using skeletal characters. The type species (D. spathulifera) and two other species (D. alcicornis and D. armata) form a well-supported clade, but the fourth species (D. reticulata) is more closely-related to certain other calloporid genera. Therefore, the reticulate frontal wall is inferred to have evolved twice and D. reticulata is removed to Doryporellina gen. n. Biogeographical distributions of the four species are reviewed. Andrei V. Grischenko, Department of Hydrobiology and Ichthyology, Faculty of Biology and Soil Sciences, St Petersburg State University, 16 Liniya 29, St Petersburg, 199178, Russia (address for correspondence: Phontannaya 4-92, Perm 614002, Russia). E-mail: gat@mail.perm.ru Shunsuke F. Mawatari, Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060, Japan. E-mail: shunfm@sci.hokudai.ac.jp Paul D. Taylor, Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK. E-mail: pdt@nhm.ac.uk lackwell Science, Ltd Systematics and phylogeny of the cheilostome bryozoan Doryporella ANDREI V. GRISCHENKO, SHUNSUKE F. MAWATARI & PAUL D. TAYLOR Accepted: 25 October 1999 Introduction Doryporella is a distinctive and yet poorly known cheilostome bryozoan with an Arctic-Boreal distribution and no fossil record. Species of Doryporella are recognizable by the unusual polygonal, reticulate ornamentation of their frontal walls, a feature not found in the other genera of calloporid anascans with which Doryporella has usually been grouped. In some species, including the type species D. spathulifera (Smitt 1868), the frontal wall is so extensive and ascophoran-like that the identity of the genus as an anascan cheilostome has been called into question. Levinsen (1916), for example, when placing D. spathulifera into the anascan genus and subgenus Mem- branipora (Callopora), noted that it had been referred by previous workers to three different genera of ascophorans. The origin and type of frontal wall in Doryporella has also been a matter of contention (Ryland 1963: 10): is it a gymnocyst (i.e. an exterior wall with epithelium on the inner side and cuticle on the outer side) or a cryptocyst (i.e. an interior wall with epithelium on both inner and outer sides)? Given the problems over the affinities of Doryporella and the lack of any modern descriptions utilizing scanning electron microscopy (SEM), restudy of this distinctive genus is clearly necessary. This is especially so in view of the need for data for the forthcoming revision of the cheilostome bryozoan volume of the ‘Treatise on Invertebrate Palaeontology’. Here we take advantage of newly collected material from the north- west Pacific, supplemented by existing material in The Natural History Museum, London (NHM), to undertake a systematic revision of Doryporella and to review what little is known about the biogeographical distributions and ecologies of the four nominal species. A further objective is to present an inter- pretation of the phylogenetic relationships between the species of Doryporella using cladistic methodology, and to ask whether the genus as currently understood is monophyletic. Materials and methods New specimens were obtained during cruises of the ‘ R.V. Nazarovsk’ (September 1988), the ‘R.V. Akademic Oparin’ (14th Cruise, August-September 1991) and the Middle Fishery Refrigerator Trawler ‘ Rodino’ (September 1992) to the northern Pacific. Additional material was furnished from the existing reference collections of bryozoans held in the Department of Zoology at The Natural History Museum, London. Most of the SEM was undertaken on dried, uncoated colonies,