title: First occurrence of the non-native bryozoan Schizoporella japonica Ortmann (1890) in Western Europe.
abstract: Schizoporella japonica Ortmann was described from Japan but was subsequently introduced on Pacific oysters to the Pacific coast of North America, where it is now well established. In this paper we record it for the first time in European waters. The initial discovery was in a marina at Holyhead, North Wales, in July 2010 but S. japonica has since been observed abundantly in the Orkney Islands (from May 2011) and, subsequently, at other localities in northern Scotland. Introduction seems most likely to have been on an ocean-going vessel. The British material is here fully described and illustrated with SEMs and colour photographs; some unusual characters are discussed. Unlike other recently introduced bryozoans, S. japonica is a cold-water species and its breeding season in Britain extends through the winter. Extensive confusion between this and other species of Schizoporella on the west coast of Canada and the USA led us to make thorough morphometric comparisons between the species concerned (Schizoporella unicornis (Johnston in Wood), Schizoporella errata (Waters) and Schizoporella pseudoerrata Soule, Soule and Chaney). Zooid size in cheilostomate bryozoans is variable and often an unreliable character for species separation but shape (and therefore ratios between variables, which are independent of size) are often valuable: S. japonica zooids have a much greater length:width ratio than the other species. Density of frontal pseudopores provides a useful discriminatory character. Schizoporella unicornis, repeatedly reported in error from the Pacific coast of North America, does not occur there; it is a European species. Full comparisons are made between S. japonica and S. unicornis for European identification and between S. japonica, S. errata and S. pseudoerrata (which are also illustrated) for North American localities.
authors.affiliation: Department of Biosciences, Wallace Building, Swansea University, Swansea SA2 8PP, Wales UK. E-mail: j.s.ryland@swansea.ac.uk 2Natural Resources Wales, Maes Y Ffynnon, Bangor LL57 2DW, Wales UK; Email: unknown.
authors.forename: John S
authors.initials: JS
authors.lastname: Ryland
authors.affiliation: Natural Resources Wales, Maes Y Ffynnon, Bangor LL57 2DW, Wales UK; Email: unknown.
authors.forename: Rohan
authors.initials: R
authors.lastname: Holt
authors.affiliation: School of Life Sciences, Centre for Marine Biodiversity and Biotechnology, Heriot-Watt University, James Muir Building, Gait 1, Edinburgh EH14 4AS, Scotland UK Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, England UK University Marine Biological Station Millport, Isle of Cumbrae KA28 0EG, Scotland UK; Email: unknown.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Loxton
mesh_terms: D000825:Animal Structures / Q000033:anatomy & histology / Q000254:growth & development; D000818:Animals; D049628:Body Size; D002013:Bryozoa / Q000033:anatomy & histology / Q000145:classification* / Q000254:growth & development; D005060:Europe