2000-2012 John Bishop United Kingdom Non-Native Data dataset https://portal.medin.org.uk/portal/start.php?tpc=010_fb328ca266edbc975f78bb7b11b4cefc Non-native ascidians can be a major feature of sessile communities, particularly in artificial habitats, but may be overlooked because of poor understanding of speciesâ?? taxonomy and biogeographic status. The styelid unitary ascidian Asterocarpa humilis , up to now only reported in the Southern Hemisphere, has been found on the coast of NW France from St Malo to Quiberon, on the south coast of England from Falmouth to Brighton, and also in north Wales. The first documented occurrence was in 2005 in Brittany, but the species was found to be relatively widespread at a regional scale and common in many places during surveys in 2009, 2010 and 2011. It has possibly been present but overlooked for some time. The identification based on morphology was confirmed by comparison with specimens from New Zealand, within the speciesâ?? presumed native range, by molecular barcoding based on mitochondrial (COI) and nuclear (18S) genes. Publications used in this dataset include: F.Arenas et al Alien species and other notable records from a rapid assessment survey of marinas on the south coast of England J.Mar. Biol. Ass. UK. 2006, 86 1329-1337. John DD Bishop et al Surveys of marinas and harbours on the south and east coasts of England for the invasive ascidian Didemnum vexillum (October-December 2009) Internal DEFRA report. John DD Bishop et al Surveys for the invasive ascidian Didemnum vexillum in the Dart and Kingsbridge-Salcombe estuaries, Devon, in October 2009 Internal DEFRA report. John DD Bishop et alThe Southern Hemisphere ascidian Asterocarpa humilis is unrecognised but widely established in NW France and Great Britain. 20171218