Recent molecular studies have shown that the sponge order Haploslcerida is polyphyletic as the freshwater sponges appear to be more closely related to other demosponges than they are to the marine haplosclerids. Within the marine haplosclerid clade relationships viewed via 18S and 28S rRNA gene phylogenies suggest that the suborders and many families and genera are also polyphyletic. However, both of these genes are on the same locus and do not evolve completely independently. We have analysed mitochondrial Cytochrome oxidase 1 gene fragments from 44 species of marine Haplosclerida and show conclusively that the classification of this group needs complete revision. Molecular data show a very complicated phylogeny supporting very few morphological hypotheses and little geographical pattern. However, the molecular data contain a great deal of phylogenetic signal at many taxonomic levels and support phylogenies drawn from the other genes.

Recent phylogenetic analyses of demosponges have suggested that the order Poecilosclerida is monophyletic and nested within the paraphyletic ‘order’ Hadromerida. Until now, this result has rested upon very limited taxon sampling of SSU sequences and partial LSU sequences. We collected and analysed additional full-length SSU and LSU sequences to test the validity and position of the poecilosclerid/hadromerid clade within demosponges, and we sampled a short segment of the LSU from diverse hadromerids to explore the internal relationships of Hadromerida. Our data strongly support the existence of a hadromerid/poecilosclerid clade that is sister to a poorly characterized group of halichondrid and agelasid species (‘Clade C’). We find support for the monophyly of the hadromerid families Polymastiidae, Placospongiidae and Timeidae, and conditional support for the family Suberitidae. Furthermore, both LSU and SSU data support a clade that includes a mixture of species assigned to the families Tethyidae and Hemiasterellidae (TETH/HEM) and a mixed clade including members of the families Clionaidae and Spirastrellidae (CLIO/SPIR). The family Placospongiidae is reconstructed as sister to the clade CLIO/SPIR and the family Timeidae is supported as sister to the clade TETH/HEM. The order Poecilosclerida is most closely allied with the Placospongiidae/CLIO/SPIR clade.

Three species of sponges, Axinella aruensis, Phakellia sp. and Acanthella cavernosa, were selected to investigate the extent of intragenomic variation (IGV) in the internal transcribed spacers (ITS-1 and ITS-2) of the ribosomal DNA within the order Halichondrida. The IGV was detected in both the spacers and in the three species. At least three non-identical sequences were found in any single individual with the number of polymorphic sites within species ranging from 6 to 77. Uncorrected distance values up to 29% were observed in the ITS-2 of Axinella aruensis. The levels of polymorphism found in this species are the highest reported for Porifera and comparable to those observed in hybrid species of scleractinean corals. Analyses of ITS sequences from multiple clones from individuals of Halichondrida are strongly recommended if these genetic markers are to be used to depict phylogenetic and/or phylogeographic relationships of closely related species and their populations. Data from other nuclear and mitochondrial markers should be used to complement conclusions derived from studies based on ITS sequences.

The ribosome is the location of protein translation and therefore a pivotal macromolecular complex for all organisms. The RNA molecules involved in the formation and functioning of the ribosome (rRNA) are partially single-stranded (loops) and partially double-stranded (helices or stems) as a result of pairing of complementary regions in either their own or other rRNA subunits. This pattern provides the rRNA with a secondary structure crucial for its functionality. The stability of these secondary structures is mediated by their base compositions: a helix rich in G-C pairs possesses a higher thermodynamic stability than an A-T rich counterpart. However, the base composition of these structures is neither homogeneous throughout the molecule nor throughout the demosponge taxa. Here, we present patterns of biased nucleotide composition in demosponge 28S rDNA. We analyse their correlation in respect to environment and taxonomy. We find significantly higher G+C contents in haplosclerid demosponges compared to other orders and investigate evidence for an association between water temperature and rRNA base composition in demosponges.

The genus Tethya represents a large cosmopolitan group of 81 recognized and a significant number of additional, still undescribed sponge species. The phylogenetic relationships within this old taxon are almost unknown. This is represented by the fact that several species are regarded as cosmopolitan. However, some of them might represent groups of closely related but distinct species. Using molecular and morphological characters, we aimed at a fundamental phylogenetic study for the genus Tethya, evaluating an existing morphological matrix and the cytochrome oxidase subunit I (COI) as a molecular marker. Intending to create a basic phylogenetic framework for the genus we selected a number of species from main biogeographic regions covered by Tethya species: from the Mediterranean Sea (T. citrina and T. aurantium), the northern European seas (T. citrina, T. norvegica and T. hibernica), the western Atlantic (T. actinia), the eastern Pacific (T. californiana), the Indo-Pacific (T. seychellensis) as well as three species of unknown biogeographical origin, originally described from aquarium habitats (T. wilhelma, T. gracilis and T. minuta). Both the morphological matrix, consisting of 29 characters and 131 character states, as well as the molecular matrices (COI nucleotide sequences of 658 bp as well as deduced amino acid sequence of 219 aa), resolved major biogeographical subgroups within the genus. However, the nucleotide based matrices revealed a higher resolution. Two major branches seem to have diverged early: an Indo-Pacific (T. seychellensis, T. wilhelma, T. minuta) and a Pan-European clade (T. citrina, T. norvegica, T. hibernica). For T. aurantium as well as a North-American group (T. californiana, T. actinia and T. minuta) our results are not conclusive. The morphological character set will have to be re-evaluated to gain a higher phylogenetic resolution. The addition of more species to our basal phylogenetic framework will allow analysing the evolution of the various biogeographical subgroups in the genus Tethya.

Sponges (Phylum Porifera) are among the most ancestral metazoans and are frequently difficult to identify, even by taxonomic experts, due to their lack of complex morphological characters. However, poriferans are highly diverse, ecologically important and of significant importance to pharmaceutical and biomaterials industries. Therefore, means of unambiguous identification are urgently needed. A DNA taxonomic system, and in particular sponge DNA barcodes, will provide a set of indispensable tools to aid taxonomists and ecologists in the rapid identification of sponge species, which will enhance the discovery of drug-producing species. Here, we will argue for the implementation of a DNA supported taxonomic system and introduce the Sponge Barcoding Project.

The species diversity and distribution of demosponges dwelling in the coral reefs, at Had Khanom—Mo Ko Thale Tai National Park on the southern coast of the Gulf of Thailand, was investigated, with field surveys undertaken at 12 sites in November 2006 using SCUBA diving and random observation. Forty-five species of demosponges from 10 orders, 24 families and 34 genera were recorded. The most abundant and common sponges in this area are: Oceanapia sagittaria; Neopetrosia sp. blue; Xestospongia testudinaria; and Haliclona (Gellius) cymaeformis. Most species are common representatives of the Indo-Pacific fauna found throughout the Gulf of Thailand.

Seamounts, although abundant features of the world's oceans, constitute one of the least studied marine ecosystems. In the present work we assessed the diversity and zoogeographical affinities of the demosponge assemblages of Gettysburg and Ormonde Seamounts (Gorringe Bank, north-east Atlantic). Twenty-three demosponge species were identified adding to the thirteen previously reported for Gorringe shallow-water. Gorringe's demosponge assemblage was found to be mainly composed of species with a wide Atlanto–Mediterranean distribution (61%) and a group of species (28%) that are endemic to this Bank or have a restricted geographical distribution. This high level of endemism suggests the Gorringe Bank as a hotspot for demosponge fauna in the north-east Atlantic. Gorringe demosponge fauna was found to present an overall moderate similarity to the Mediterranean, Iberian coasts and Macaronesian archipelagos. We compare our findings with patterns reported for fish and molluscan faunas for this Bank and discuss some evolutionary aspects on the role of these ecosystems for the north-east Atlantic marine biota.

Lough Hyne was Europe's first Marine Nature Reserve and is a well known biodiversity hotspot that supports extensive sponge assemblages. The unusual, but predictable, flow and sedimentation regimes have important impacts on the sponge assemblages at the species and assemblage levels. Here I present a review of recent sponge research at Lough Hyne, which covers: (1) a description of the sponge-dominated habitats; (2) the biological and physical factors controlling sponge biodiversity and abundance; (3) sponge species and assemblage level morphological variability; and (4) the relationship between sponge morphological, species and functional diversity. It appears that physical factors are primarily responsible for the sponge diversity and abundance patterns found in Lough Hyne, although the importance of intra- and interphyletic (particularly with algae) competitive interactions requires further investigation. Although our knowledge of how sponges respond and adapt to environmental variability has increased substantially because of the research conducted at Lough Hyne, I have highlighted a number of future research areas in the context of Lough Hyne sponge assemblages, which are relevant to understanding structuring processes across the globe.

Relatively little is known about spatial turnover of marine benthic taxa in the diverse reef environments of Indonesia and how this is structured by environmental conditions. In the present study the community similarity of sponges was related to environmental and spatial variables. In total, 150 sponge species (N=15,842) were sampled within the Spermonde Archipelago in the Makassar Strait, off south-west Sulawesi. Ordination revealed that sponges are primarily structured by a complex interaction between depth, exposure and on-to-offshore variation in environmental variables. Together, environmental and spatial variables explained 56.9% of the variation in similarity of which 10.9% was due to environmental variables alone, 2.6% due to spatial variables alone and 43.4% due to covariation of environmental and spatial variables. The large amount of variation explained by the spatially structured environmental component is due to a strong on-to-offshore gradient in a number of environmental variables including temperature, velocity, salinity and suspended sediment load. Ordination was also used to identify associations between species and environmental variables.

The present publication presents oxygen properties and pumping behaviour of Dysidea avara. Oxygen profiles were measured near and inside the atrial space of the osculum with a Clark-type micro-electrode. Pumping sponges had profiles with oxygen concentrations marginally lower than that of the aquarium water. In contrast, diffusive profiles, with a clear boundary layer above the sponge surface, and oxygen penetrating only 0.5 mm into the sponge tissue, were typically that of a sponge which was not pumping. Diffusive oxygen flux at the sponge surface was 4.2 μmol O2 cm2 d1 and the calculated volumetric filtration rate was 0.3 cm3 water cm3 sponge min1. The oxygen concentration in the osculum was temporally fluctuating between 95 and 59% saturation at a frequency of approximately once per minute. The combination of static oxygen micro-electrode measurements and particle tracking velocimetry (PTV) allowed us to simultaneously observe fine-scale oxygen fluxes and oscular flow patterns in active sponges, even at extremely low pumping rates. Oscular oxygen concentration and flow were correlated but not always synchronous to the second. Particle tracking velocimetry was used to visualize the flow field around the sponge and to distinguish sponge-generated flow from the unidirectional current in a flow-cell.

Marine sponges are abundant and diverse components of coral reefs and commonly harbour photosynthetic symbionts in these environments. The most prevalent symbiont is the cyanobacterium, Synechococcus spongiarum, isolated from taxonomically diverse hosts from geographically distant regions. We combined analyses of chlorophyll-a (chl-a) concentrations with line-intercept transect surveys to assess the abundance and diversity of reef sponges hosting photosymbionts on Caribbean coral reefs in the Bocas del Toro Archipelago, Panamá. To identify symbionts, we designed PCR primers that specifically amplify a fragment of the 16S ribosomal RNA gene from S. spongiarum and used these primers to screen potential host sponges for the presence of this symbiont. Chlorophyll-a data divided the sponge community into two disparate groups, species with high (>125 μg/g, N=20) and low (<50 μg/g, N=38) chl-a concentrations. Only two species exhibited intermediate (50–125 μg/g) chl-a concentrations; these species represented hosts with reduced symbiont populations, including bleached Xestospongia muta and the mangrove form of Chondrilla nucula (C. nucula f. hermatypica). Sponges with high and intermediate chl-a concentrations accounted for over one-third of the species diversity and abundance of sponges in these communities. Most (85%) of these sponges harboured S. spongiarum. Molecular phylogenies reveal that S. spongiarum represents a sponge-specific Synechococcus lineage, distinct from free-living cyanobacteria. The prevalence of sponge–photosymbiont associations and dominance of symbiont communities by S. spongiarum suggest a major role of this cyanobacterium in sponge ecology and primary productivity on coral reefs.

This study reports on the transfer of heterotrophic bacteria from parental tissue to oocytes in the Mediterranean bacteriosponge Corticium candelabrum (Homosclerophorida) and the description of the successive locations of the microsymbionts during embryo development through transmission and scanning electron microscopy. Eight different types of symbiotic bacteria are described morphologically. These eight bacteria morphotypes are found in both adult individuals and larvae. Symbiotic bacteria are transferred to oocytes, but not to spermatocytes. Bacteria are first located at the oocyte periphery below a thick collagen layer and then they migrate to the oocyte cytoplasm, forming spherical clusters. After cleavage, the bacteria can be found in the free space between blastomeres but mainly accumulate at the embryo periphery below the follicular cells that surround the embryo. Once the blastocoel is formed, the symbiotic bacteria move to this central cavity where they actively divide by bipartition, increasing their number considerably. Many examples of phagocytosed bacteria in the proximal zone of the larval cells are observed at this stage. Consequently, bacteria may represent a complementary source of energy for free larvae and settlers before they are able to capture food from the surrounding water.

Recent molecular detection of vast microbial communities exclusively associated with sponges has made evident the need for a better understanding of the mechanisms by which these symbiotic microbes are handled and transferred from one sponge generation to another. This transmission electron microscopy (TEM) study investigated the occurrence of symbiotic bacteria in free-swimming larvae of two viviparous species (Haliclona caerulea and Corticium candelabrum) and spawned gametes of two oviparous species (Chondrilla nucula and Petrosia ficiformis). Complex microbial communities were found in these sponges, which in two cases included bacteria characterized by an intra-cytoplasmic membrane (ICM). When ICM-bearing and ICM-lacking bacteria co-existed, they were transferred following identical pathways. Nevertheless, the mechanism for microbial transference varied substantially between species. In C. nucula, a combination of intercellular symbiotic ICM-bearing and ICM-lacking bacteria, along with cyanobacteria and yeasts, were collected from the mesohyl by amoeboid nurse cells, then transported and transferred to the oocytes. In the case of Corticium candelabrum, intercellular bacteria did not enter the gametes, but spread into the division furrows of early embryos and proliferated in the central cavity of the free-swimming larva. Surprisingly, symbiotic bacteria were not vertically transmitted by P. ficiformis gametes or embryos, but apparently acquired from the environment by the juveniles of each new generation. This study failed to unravel the mechanism by which the intercellular endosymbiotic bacterium found in the central mesohyl of the H. caerulea larva got there. Nevertheless, the ultrastructure of this bacterial rod, which was characterized by a star-shaped cross section with nine radial protrusions, an ICM-bound riboplasm, and a putative membrane-bound acidocalcisome, suggested that it may represent a novel organization grade within the prokaryotes. It combines traits occurring in members of Poribacteria, Planctomycetes and Verrucomicrobia, emerging as one of the most complex prokaryotic architectures known to date.

Reports of disease in sponges are increasing, but the paucity of data on disease prevalence over time makes it uncertain how much this trend reflects increased attention to sponges rather than increased sponge disease. Population and community influences on disease dynamics, and the consequences of disease at these levels, are also little known. Five censuses, over 14 y, of a small plot on a shallow coral reef at San Blas, Panama, provide data for the three most abundant species on population dynamics (number of individuals and total volume) and disease prevalence (number of individuals with active lesions). Although data for the three species, combined in broad categories (i.e. high vs low), support a general conclusion that disease prevalence was greater from 1994–1998 than from 1984–1988, the data do not demonstrate a steady increase over time, and disease prevalence for two of the species decreased in each of the final two censuses from a high in 1994. Fluctuations in population density (total volume) and disease prevalence were nearly synchronous within individual species, but asynchronous among the three species, suggesting that population density, measured as total sponge volume per unit area, may influence disease dynamics in these sponges.

Deep water cladorhizids are now generally thought to be carnivorous. While the methods of prey capture have been established for species of Asbestopluma, and perhaps Chondrocladia, information is sparse for species of Cladorhiza. The external morphology of the deep-sea Alaskan species, Cladorhiza corona, was examined immediately after collection, and then again later using scanning electron microscopy (SEM). All sponges examined had captured, and in most cases, fully encased, prey items which for the most part consisted of planktonic copepods. The hypothesis of this paper is that the primary process of prey capture is by means of a sticky substance and that prey stick to the sponge on contact. The abundant cladorhizid anisochelae do not seem to be arranged in a manner such that they can be used for prey capture as has been seen in Asbestopluma. Digestion of the prey occurs in a temporary cavity created by migrating sponge cells. Within this cavity lipid from the copepod is liberated, then absorbed and transported to the central part of the sponge. It is not known how much of the remaining tissue of the copepod is digested. Copepods have very high lipid content so their capture would provide the sponge with abundant energy from each prey item. The sponges seem to have their highest density in areas where bottom flow and migrating copepod numbers are both high.

Chondrilla nucula is a morphologically simple species defined by the presence of spherasters in its skeleton. For a long time C. nucula was considered a cosmopolitan species, however, in 1999, a molecular study demonstrated the existence of a species complex with at least four cryptic species, besides C. nucula. At that time, those four new species were not formally described because the morphological differences observed did not reflect species differences and were attributed to plasticity. Since then, researchers working on Chondrilla species suggested that the skeletal organization, the distribution of spherulous cells and the type of surface should be used to differentiate species. Individuals of Chondrilla aff. nucula from one population in Arraial do Cabo, Rio de Janeiro State, Brazil, were collected monthly and analysed in order to test the validity of those three characters to separate the species of Chondrilla. Moreover, to determine if the differences in spicule dimensions previously found were seasonal, we also quantified the diameter of the spherasters throughout the year. Our results demonstrate that all analysed characters are extremely variable and that spicule size can vary even at the same locality. The present study shows the importance of testing the variability of morphological characters before describing new species. Unfortunately, until valid taxonomic characters are found, the Atlantic Chondrilla species will have to remain undescribed.

Continuous monitoring by scientists and volunteers of the Biological Working Group of the Dutch SubAqua Union and the ‘Anemoon’ Foundation over the past four years, yielded a surprising six new records of sponges for Dutch coastal waters. Oscarella lobularis, Celtodoryx girardae, Suberites virgultosus, Haliclona (Haliclona) simulans, Halisarca aff. dujardini, and a species identified as Leucosolenia somesii were unknown from Dutch coastal waters before 2000. The latter is a giant calcareous sponge, seemingly belonging to the common Leucosolenia variabilis, but here assumed to be an invader as well, as it has spicular characters well outside the variation found in the majority of Dutch L. variabilis specimens. It is likely a member of a ‘forgotten’ species, L. somesii. Habit photographs, SEM images of the spicules, and for O. lobularis and H. aff. dujardini, photographs of histological sections are provided to substantiate these new records. With the exception of C. girardae, most of the species resemble previously described widespread north-east Atlantic species, occurring in the area to the south and west of the Netherlands, so it is assumed pending future genetic research that at least several of the invaders comprise range extensions related to rising winter temperatures. Possibly, recent shellfish imports may be an additional causal agent. We also report the occurrence of unprecedented spicular deviations observed in three sponge species commonly occurring in Dutch waters, Halichondria (Halichondria) panicea, Hymeniacidon perlevis and Haliclona (Soestella) xena, which grew in small inland water bodies. Possibly, the limited space in these inland waters with possible stress factors for sponges such as reduced water exchange, and deviating chemistry, have caused the sponges to form stunted growth in spicules varying from rhabds with rounded endings to silica spheroids. We provide an updated list of sponges found in Dutch waters and a list of suspected or proven invaders of Dutch waters.

The calcareous sponge Paraleucilla magna has been detected at different Mediterranean sites (Taranto, Porto Cesareo, Brindisi and Naples). Its record in well studied areas where several benthic surveys have previously been carried out suggests a recent introduction of the species into the Mediterranean Sea. Until now this sponge has only been recorded from the Brazilian coast. It shows different morphologies, varying from tubular to an irregular massive shape with several folds occurring on its surface. The colour is white-cream. The surface is smooth. The consistency is friable. The oscula are 10–20 mm in diameter and located at the top of tubular protrusions. The skeleton consists of cortical and subatrial triactines and tetractines, together with atrial triactines, differently distributed in the sponge body. Paraleucilla magna is abundant in eutrophic environments, where seasonally it may reach very high frequency values and large dimensions. It is resistant to pollution, but it is also able to live in clean waters. The inclusion of this species among Mediterranean alien invasive species is suggested.

A detailed account of sponge knowledge in Greek antiquity is given on the basis of their records in the written documents of the historical periods it comprises. The analysis of the examined material revealed interesting information on various aspects of sponge biology, more or less consistent with their present scientific knowledge. The value of sponges for man at that time was evident in many of his activities, such as household, personal hygiene, pain relief, disease treatment, art and war enterprises. The significant role of sponges in medical practice is illustrated by the high number of their records in the medical works of the studied historical period. Furthermore, sponges appeared in legends, as well as in similes and metaphors that attributed their special qualities to human behaviour, various body parts or objects.