title: The systematics of carnivorous sponges.
abstract: Carnivorous sponges are characterized by their unique method of capturing mesoplanktonic prey coupled with the complete or partial reduction of the aquiferous system characteristic of the phylum Porifera. Current systematics place the vast majority of carnivorous sponges within Cladorhizidae, with certain species assigned to Guitarridae and Esperiopsidae. Morphological characters have not been able to show whether this classification is evolutionary accurate, and whether carnivory has evolved once or in several lineages. In the present paper we present the first comprehensive molecular phylogeny of the carnivorous sponges, interpret these results in conjunction with morphological characters, and propose a revised classification of the group. Molecular phylogenies were inferred using 18S rDNA and a combined dataset of partial 28S rDNA, COI and ALG11 sequences. The results recovered carnivorous sponges as a clade closely related to the families Mycalidae and Guitarridae, showing family Cladorhizidae to be monophyletic and also including carnivorous species currently placed in other families. The genus Lycopodina is resurrected for species currently placed in the paraphyletic subgenus Asbestopluma (Asbestopluma) featuring forceps spicules and lacking sigmas or sigmancistras. The genera Chondrocladia and Cladorhiza are found to be monophyletic. However, results indicate that the subgenus Chondrocladia is polyphyletic with respect to the subgenera Meliiderma and Symmetrocladia. Euchelipluma, formerly Guitarridae, is retained, but transferred to Cladorhizidae. The four known carnivorous species currently in Esperiopsis are transferred to Abyssocladia. Neocladia is a junior homonym and is here renamed Koltunicladia. Our results provide strong evidence in support of the hypothesis that carnivory in sponges has evolved only once. While spicule characters mostly reflect monophyletic groups at the generic level, differences between genera represent evolution within family Cladorhizidae rather than evolution of carnivory in separate lineages. Conflicting spicule characters can be reinterpreted to support the inclusion of all carnivorous sponges within Cladorhizidae, and a carnivorous habit should thus be considered the main diagnostic character in systematic classification.
authors.affiliation: Department of Biology and Centre for Geobiology, University of Bergen, P.O. Box 7803, N-5020 Bergen, Norway. Electronic address: jon.hestetun@uib.no.
authors.forename: Jon Thomassen
authors.initials: JT
authors.lastname: Hestetun
authors.affiliation: Aix Marseille Université, CNRS, IRD, Avignon Université, IMBE UMR 7263, 13397 Marseille, France. Electronic address: jean.vacelet@imbe.fr.
authors.forename: Jean
authors.initials: J
authors.lastname: Vacelet
authors.affiliation: Aix Marseille Université, CNRS, IRD, Avignon Université, IMBE UMR 7263, 13397 Marseille, France. Electronic address: nicole.boury-esnault@orange.fr.
authors.forename: Nicole
authors.initials: N
authors.lastname: Boury-Esnault
authors.affiliation: Aix Marseille Université, CNRS, IRD, Avignon Université, IMBE UMR 7263, 13397 Marseille, France. Electronic address: carole.borchiellini@imbe.fr.
authors.forename: Carole
authors.initials: C
authors.lastname: Borchiellini
authors.affiliation: National Centre for Aquatic Biodiversity and Biosecurity, National Institute of Water and Atmospheric Research, P.O. Box 109-695, Newmarket, Auckland, New Zealand. Electronic address: michelle.kelly@niwa.co.nz.
authors.forename: Michelle
authors.initials: M
authors.lastname: Kelly
authors.affiliation: Instituto Español de Oceanografía, Centro Oceanográfico de Gijón, Av./Príncipe de Asturias 70 bis, 33212 Gijón, Asturias, Spain. Electronic address: pilar.rios.lopez@gmail.com.
authors.forename: Pilar
authors.initials: P
authors.lastname: Ríos
authors.affiliation: Instituto Español de Oceanografía, Centro Oceanográfico de Gijón, Av./Príncipe de Asturias 70 bis, 33212 Gijón, Asturias, Spain; Departamento de Zoología y Antropología Física, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain. Electronic address: cristobo@gi.ieo.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Cristobo
authors.affiliation: Department of Biology and Centre for Geobiology, University of Bergen, P.O. Box 7803, N-5020 Bergen, Norway; Uni Environment, P.O. Box 7810, N-5020 Bergen, Norway. Electronic address: hans.rapp@uib.no.
authors.forename: Hans Tore
authors.initials: HT
authors.lastname: Rapp
mesh_terms: D000818:Animals; D005075:Biological Evolution; D060435:Carnivory; D004275:DNA, Ribosomal / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D010802:Phylogeny; D011161:Porifera / Q000145:classification / Q000235:genetics / Q000502:physiology*; D011235:Predatory Behavior; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012339:RNA, Ribosomal, 28S / Q000235:genetics
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S; D003576:Electron Transport Complex IV
keywords: Abyssocladia; Asbestopluma; Chondrocladia; Cladorhizidae; Phylogeny; Porifera