title: Global diversity of sponges (Porifera).
abstract: With the completion of a single unified classification, the Systema Porifera (SP) and subsequent development of an online species database, the World Porifera Database (WPD), we are now equipped to provide a first comprehensive picture of the global biodiversity of the Porifera. An introductory overview of the four classes of the Porifera is followed by a description of the structure of our main source of data for this paper, the WPD. From this we extracted numbers of all 'known' sponges to date: the number of valid Recent sponges is established at 8,553, with the vast majority, 83%, belonging to the class Demospongiae. We also mapped for the first time the species richness of a comprehensive set of marine ecoregions of the world, data also extracted from the WPD. Perhaps not surprisingly, these distributions appear to show a strong bias towards collection and taxonomy efforts. Only when species richness is accumulated into large marine realms does a pattern emerge that is also recognized in many other marine animal groups: high numbers in tropical regions, lesser numbers in the colder parts of the world oceans. Preliminary similarity analysis of a matrix of species and marine ecoregions extracted from the WPD failed to yield a consistent hierarchical pattern of ecoregions into marine provinces. Global sponge diversity information is mostly generated in regional projects and resources: results obtained demonstrate that regional approaches to analytical biogeography are at present more likely to achieve insights into the biogeographic history of sponges than a global perspective, which appears currently too ambitious. We also review information on invasive sponges that might well have some influence on distribution patterns of the future.
authors.affiliation: Netherlands Centre for Biodiversity Naturalis, Leiden, The Netherlands. rob.vansoest@ncbnaturalis.nl
authors.forename: Rob W M
authors.initials: RW
authors.lastname: Van Soest
authors.forename: Nicole
authors.initials: N
authors.lastname: Boury-Esnault
authors.forename: Jean
authors.initials: J
authors.lastname: Vacelet
authors.forename: Martin
authors.initials: M
authors.lastname: Dohrmann
authors.forename: Dirk
authors.initials: D
authors.lastname: Erpenbeck
authors.forename: Nicole J
authors.initials: NJ
authors.lastname: De Voogd
authors.forename: Nadiezhda
authors.initials: N
authors.lastname: Santodomingo
authors.forename: Bart
authors.initials: B
authors.lastname: Vanhoorne
authors.forename: Michelle
authors.initials: M
authors.lastname: Kelly
authors.forename: John N A
authors.initials: JN
authors.lastname: Hooper
mesh_terms: D000818:Animals; D044822:Biodiversity; D016208:Databases, Factual; D003710:Demography; D009792:Oceans and Seas; D011161:Porifera / Q000145:classification* / Q000235:genetics* / Q000502:physiology*; D013045:Species Specificity