title: The slugs of Britain and Ireland: undetected and undescribed species increase a well-studied, economically important fauna by more than 20%.
abstract: The slugs of Britain and Ireland form a well-studied fauna of economic importance. They include many widespread European species that are introduced elsewhere (at least half of the 36 currently recorded British species are established in North America, for example). To test the contention that the British and Irish fauna consists of 36 species, and to verify the identity of each, a species delimitation study was conducted based on a geographically wide survey. Comparisons between mitochondrial DNA (COI, 16S), nuclear DNA (ITS-1) and morphology were investigated with reference to interspecific hybridisation. Species delimitation of the fauna produced a primary species hypothesis of 47 putative species. This was refined to a secondary species hypothesis of 44 species by integration with morphological and other data. Thirty six of these correspond to the known fauna (two species in Arion subgenus Carinarion were scarcely distinct and Arion (Mesarion) subfuscus consisted of two near-cryptic species). However, by the same criteria a further eight previously undetected species (22% of the fauna) are established in Britain and/or Ireland. Although overlooked, none are strictly morphologically cryptic, and some appear previously undescribed. Most of the additional species are probably accidentally introduced, and several are already widespread in Britain and Ireland (and thus perhaps elsewhere). At least three may be plant pests. Some evidence was found for interspecific hybridisation among the large Arion species (although not involving A. flagellus) and more unexpectedly in species pairs in Deroceras (Agriolimacidae) and Limacus (Limacidae). In the latter groups, introgression appears to have occurred in one direction only, with recently-invading lineages becoming common at the expense of long-established or native ones. The results show how even a well-studied, macroscopic fauna can be vulnerable to cryptic and undetected invasions and changes.
authors.affiliation: National Museum of Wales, Cardiff, Wales, United Kingdom.
authors.forename: Ben
authors.initials: B
authors.lastname: Rowson
authors.affiliation: Conchological Society of Great Britain & Ireland, Belfast, Northern Ireland, United Kingdom.
authors.forename: Roy
authors.initials: R
authors.lastname: Anderson
authors.affiliation: National Museum of Wales, Cardiff, Wales, United Kingdom.
authors.forename: James A
authors.initials: JA
authors.lastname: Turner
authors.affiliation: Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom.
authors.forename: William O C
authors.initials: WO
authors.lastname: Symondson
mesh_terms: D000818:Animals; D044822:Biodiversity; D049851:Gastropoda / Q000033:anatomy & histology / Q000235:genetics*; D014644:Genetic Variation; D006239:Haplotypes; D007494:Ireland; D010802:Phylogeny; D013045:Species Specificity; D006113:United Kingdom
references.citation: Syst Biol. 2012 Jan;61(1):165-9
references.pmid: 21482553
references.citation: Mol Mar Biol Biotechnol. 1991 Sep;1(1):27-34
references.pmid: 1669002
references.citation: Mol Ecol Resour. 2009 Jul;9(4):1092-101
references.pmid: 21564847
references.citation: Front Zool. 2010 May 25;7:16
references.pmid: 20500846
references.citation: PLoS One. 2012;7(6):e37945
references.pmid: 22701588
references.citation: Proc Biol Sci. 2011 Feb 7;278(1704):347-55
references.pmid: 20702462
references.citation: Syst Biol. 2006 Aug;55(4):595-609
references.pmid: 16967577
references.citation: Proc Biol Sci. 2004 May 7;271 Suppl 4:S189-92
references.pmid: 15252980
references.citation: Mol Ecol. 2012 Jun;21(11):2671-91
references.pmid: 22494453
references.citation: Mol Mar Biol Biotechnol. 1994 Oct;3(5):294-9
references.pmid: 7881515
references.citation: PLoS One. 2013;8(4):e60736
references.pmid: 23577154
references.citation: PLoS One. 2011 Feb 14;6(2):e17134
references.pmid: 21423340
references.citation: Comp Biochem Physiol A Mol Integr Physiol. 2012 Apr;161(4):443-9
references.pmid: 22248916
references.citation: J Evol Biol. 2005 Sep;18(5):1264-80
references.pmid: 16135122
references.citation: Zookeys. 2011;(156):123-39
references.pmid: 22303099
references.citation: Mol Ecol. 2012 Apr;21(8):1864-77
references.pmid: 21883587
references.citation: Mol Ecol Resour. 2012 Nov;12(6):990-8
references.pmid: 22931682
references.citation: Trends Ecol Evol. 2007 Mar;22(3):148-55
references.pmid: 17129636
references.citation: PLoS One. 2013 Jun 19;8(6):e65792
references.pmid: 23840368
references.citation: Bioinformatics. 2001 Aug;17(8):754-5
references.pmid: 11524383
references.citation: Mol Biol Evol. 2011 Oct;28(10):2731-9
references.pmid: 21546353
references.citation: Mol Ecol. 2008 Nov;17(21):4684-98
references.pmid: 18992008
references.citation: Mol Ecol. 2009 Nov;18(22):4541-50
references.pmid: 19821901
references.citation: Mol Ecol. 2012 Mar;21(6):1423-37
references.pmid: 22320448