title: Molecular phylogeny of the western Palaearctic Helicoidea (Gastropoda, Stylommatophora).
abstract: The Helicoidea is one of the most diverse superfamilies of terrestrial land snails. In this study we present a molecular phylogeny of the western Palaearctic Helicoidea obtained by means of neighbor joining, maximum likelihood and Bayesian analysis of the mitochondrial 16S rRNA gene fragment and the nuclear rRNA gene cluster including the 3' end of the 5.8S gene, the complete ITS2 region and 5' end of the large subunit 28S. Most of the morphologically-defined families were confirmed. We propose a revised phylogenetic classification so that families, subfamilies and tribes are monophyletic. The family Hygromiidae sensu Hausdorf and Bouchet (2005) is divided into three clades which are here given familial rank: Canariellidae and Geomitridae, which are recognized for the first time at familial rank, and Hygromiidae s.str. (including Ciliella and Trochulus) that is here restricted. The subfamilies Ciliellinae, Geomitrinae, Hygromiinae, Monachainae and Trochulinae recognized in current classifications were not recovered as monophyletic groups. The family Cochlicellidae is here given tribe rank (Cochlicellini) belonging to the Geomitridae. We describe a new tribe, Plentuisini. Three subfamilies are recognized within Helicidae: Ariantinae, Helicinae (including Theba) and Murellinae. New classification indicates that free right ommatophore retractor muscle arose only once within Geomitridae. The anatomy of the auxiliary copulatory organs of the reproductive system of families, subfamilies and tribes is highlighted. We estimate the origin of the Helicoidea at the end of the Early Cretaceous and its families as Late-Cretaceous to Paleogene. Western Palaearctic Helicoidea belongs to two different lineages that diverged around 86Ma ago, both starting their diversification at the end of the Cretaceous (around 73-76Ma). Radiation of some western Helicoidean families started during the Eocene.
authors.affiliation: Department of Zoology and Animal Cell Biology, Faculty of Pharmacy, University of the Basque Country, Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Alava, Spain; Biodiversity Research Group CIEA Lucio Lascaray, Avda. Miguel de Unamuno 3, 01006 Alava, Spain. Electronic address: oihana.razkin@ehu.es.
authors.forename: Oihana
authors.initials: O
authors.lastname: Razkin
authors.affiliation: Department of Zoology and Animal Cell Biology, Faculty of Pharmacy, University of the Basque Country, Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Alava, Spain; Biodiversity Research Group CIEA Lucio Lascaray, Avda. Miguel de Unamuno 3, 01006 Alava, Spain. Electronic address: benjamin.gomez@ehu.es.
authors.forename: Benjamín Juán
authors.initials: BJ
authors.lastname: Gómez-Moliner
authors.affiliation: Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of the Basque Country, Barrio Sarriena s/n, 48940 Leioa, Bizkaia, Spain. Electronic address: carlos.prieto@ehu.es.
authors.forename: Carlos Enrique
authors.initials: CE
authors.lastname: Prieto
authors.affiliation: Museum of Natural History & Biotaxa, L'Hort de Feliu, Alginet P.O. Box 8460, E-46018 Valencia, Spain. Electronic address: alberto.martinez@uv.es.
authors.forename: Alberto
authors.initials: A
authors.lastname: Martínez-Ortí
authors.affiliation: Department of Animal Biology (Zoology), Faculty of Biology, University of Seville, Avda. Reina Mercedes 6, 41012 Seville, Spain. Electronic address: mastus@us.es.
authors.forename: José Ramón
authors.initials: JR
authors.lastname: Arrébola
authors.affiliation: Faculty of Biological Sciences, Complutense University of Madrid, José Antonio Novais 12, Ciudad Universitaria, 28040 Madrid, Spain. Electronic address: titomu@bio.ucm.es.
authors.forename: Benito
authors.initials: B
authors.lastname: Muñoz
authors.affiliation: Department of Zoology and Animal Cell Biology, Faculty of Pharmacy, University of the Basque Country, Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Alava, Spain; Biodiversity Research Group CIEA Lucio Lascaray, Avda. Miguel de Unamuno 3, 01006 Alava, Spain. Electronic address: luisjavier.chueca@ehu.es.
authors.forename: Luis Javier
authors.initials: LJ
authors.lastname: Chueca
authors.affiliation: Department of Zoology and Animal Cell Biology, Faculty of Pharmacy, University of the Basque Country, Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Alava, Spain; Biodiversity Research Group CIEA Lucio Lascaray, Avda. Miguel de Unamuno 3, 01006 Alava, Spain. Electronic address: mariajose.madeira@ehu.es.
authors.forename: María José
authors.initials: MJ
authors.lastname: Madeira
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D016013:Likelihood Functions; D008957:Models, Genetic; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012908:Snails / Q000145:classification* / Q000235:genetics
chemical_list: D004272:DNA, Mitochondrial; D012336:RNA, Ribosomal, 16S
keywords: Divergence time; Helicoidea; Mitochondrial rRNA; Molecular phylogeny; Nuclear rRNA; Stimulatory system