The family Hamacanthidae (Demospongiae: Merliida) is reported from the abyssal plains for the first time, represented by two new species of Hamacantha (Vomerula) collected from the polymetallic nodule fields of the Clarion-Clipperton Zone (CCZ), Pacific Ocean. Hamacantha (V.) abyssalis sp. nov. is characterized by a single category of styles and diancistras, whilst lacking other microscleres such as sigmas, toxas, or raphides. Hamacantha (V.) apodiancistra sp. nov., likely the most abundant hamacanthid in the abyssal plains, is remarkable for the complete absence of diancistras-an apomorphy previously considered diagnostic of Hamacantha. Molecular phylogenetic analyses however confirmed its placement within Hamacantha, suggesting a secondary loss of this synapomorphy. The discovery of these species nearly doubles the known bathymetric range of Hamacantha to the abyssal zone and possibly highlights evolutionary trends toward reductions in body size, skeletal complexity, and spicule diversity in deep-sea demosponges.

Antimicrobial resistance is a critical and global public health challenge, contributing to treatment failure, prolonged hospitalizations, and increased healthcare costs. Consequently, the discovery and development of new antibiotics is urgently needed. Recent studies have highlighted marine sponges as prolific sources of bioactive compounds and important reservoirs of actinomycetes, a rich source of antibiotics. In this study, 50 sponge samples were collected from Mun Nork and Mun Nai Islands in Rayong Province, Thailand, and evaluated for their antimicrobial activity and potential to harbor sponge-associated actinomycetes. Of the samples tested, 30 sponge extracts exhibited antimicrobial activity, predominantly against Gram-positive bacteria. Notably, Neopetrosia sp. (blue) demonstrated the broadest spectrum of activity, inhibiting Gram-positive and Gram-negative bacteria as well as yeast. A total of 41 actinomycete isolates were obtained from 15 sponge samples and subsequently classified into 12 genera: Micromonospora (3 isolates), Nocardia (13), Rothia (1), Isoptericola (1), Salinispora (12), Actinomycetospora (1), Pseudonocardia (1), Streptomyces (5), Mycobacterium (1), Prauserella (1), and Rhodococcus (2). Among these, three strains - Streptomyces (Strept.) althioticus RS027-1, Strept. nanshensis TR01-1, and Salinispora arenicola RS029-1 - exhibited antimicrobial activity against Kocuria rhizophila and Streptococcus pyogenes. Additionally, Salinispora arenicola RS029-1 showed broader activity, inhibiting Bacillus subtilis and Staphylococcus aureus. Based on 16S rRNA gene sequence analysis, three isolates were identified as potential novel species. The findings demonstrate that marine sponges are valuable sources of antimicrobial compounds and serve as important habitats for bioactive actinomycetes. Furthermore, marine sponges hold considerable promise for the discovery of novel actinomycete species with potential applications in future drug discovery and development.

Sponges have thrived in diverse environmental conditions since the early Cambrian until today. However, little is known about how their adaptive capability and strategies have been shaped throughout evolutionary history. Here, we explore this question based on a new leptomitid sponge fossil from the Cambrian Stage 4. The family Leptomitidae was an abundant sponge group inhabiting Cambrian soft substrates but significantly declined thereafter. The new species exhibits a sophisticated set of morphological characteristics adaptive to a shallow siliciclastic environment, which are unprecedented among leptomitids. These include (i) a robust body wall woven by spirally twisted monaxonic spicules; (ii) a thick stub-like root tuft for anchoring; (iii) spicules radiating out from the sponge body to prevent clogging and sinking; and (iv) the inferred capability to close the osculum against unfavourable stimuli. Nevertheless, the new fossil species maintains a leptomitid body plan and lacks modularity and morphological plasticity, the two common and critical attributes in extant sponges to enhance flexibility and resilience in changing environmental conditions. This juxtaposition of evolutionary innovation and structural conservatism offers a compelling case for further exploration of the evolutionary mechanisms that shaped early sponge lineages.

This study describes two new species collected from deep-sea environments in the Indo-West Pacific. Hyalonema (Cyliconema) dexiangi sp. nov., collected from the Indian Ocean, is characterized by distinctive finger-like protuberances on the body surface, the presence of choanosomal pentactins, the co-occurrence of micropentactins and microhexactins, and the absence of mesamphidiscs. Hyalonema (Cyliconema) subconica sp. nov., sampled from a seamount in the western Pacific Ocean, is distinguished by the presence of pinular diactins, a unique combination of choanosomal spicules (diactins, pentactins, and hexactins), and the presence of basalia bearing two-toothed anchors. In addition to their morphological distinctions, molecular phylogenetic analyses based on 16S rDNA sequences indicate a close genetic relationship between the two species.

Xenophyophores are large, agglutinated foraminifera that dominate the benthic megafauna in some parts of the deep sea. Here, we describe an assemblage of largely fragmentary specimens from the Clarion-Clipperton Zone (CCZ), an area of the eastern abyssal Pacific hosting large, commercially significant deposits of polymetallic nodules. We recognised 18 morphospecies of which eight yielded DNA sequences. These include two new genera and three new species, Claraclippia seminuda gen. & sp. nov., Stereodiktyoma mollis gen. & sp. nov., and Aschemonella tani sp. nov., three that are assigned to known species, Abyssalia foliformis, Aschemonella monilis and Shinkaiya contorta, and two assigned to open nomenclature forms Abyssalia aff. foliformis and Stannophyllum aff. granularium. An additional ten forms are represented only by morphology. The following seven are placed in known genera, species and open-nomenclature forms: Aschemonella? sp., Homogammina sp., Psammina multiloculata, P. aff. multiloculata, P. aff. limbata form 1 sensu Gooday et al., 2018, P. aff. limbata form 2 sensu Gooday et al., 2018, and Stannophyllum spp. The other three could not be identified to genus level. This new collection brings the total of described and undescribed species and morphotypes from the CCZ to 27 and 70, respectively, reinforcing the already high diversity of xenophyophores known from this part of the Pacific.

More than 7000 demosponge species have been described to date globally but <2% are known from the abyssal plains, which occupy some 50% of the Earth's surface. The demosponge fauna in the abyssal nodule fields at Clarion‐Clipperton Zone (CCZ) in the Pacific Ocean, a region being explored for potential deep‐sea mining, is a case in point. A total of 21 species belonging to 13 genera in nine families and seven orders were identified from the eastern region of the CCZ, of which most are new to science. They are small in size (<5 mm), with simple skeletons and poor spicule diversity. All ordinal representatives of Demospongiae were utilized to determine taxonomic position of the highly homoplasious tiny demosponges in our molecular phylogenetic analyses. Our results indicated Plenaster craigi, the most common and abundant species in the eastern CCZ, represents a new family, and possibly in a new order. Interestingly, P. craigi and members of the families Polymastiidae and Hamacanthidae, all filter‐feeding demosponge species, are far more abundant in nodule fields than the carnivorous sponges (Cladorhizidae) which were widely known to be the most dominant demosponge group in the abyssal depths. Lastly, it is highly likely that such tiny demosponges are present in other habitats. They might have been overlooked and/or ignored by sponge researchers in the past due to their tiny size and nondescript habitus. These demosponges could be distinct new species, not juveniles or indeterminates and warrant full taxonomic treatment.

Discovered in 1819 in the tropical waters off Singapore, the magnificent Neptune's cup sponge Cliona patera (Hardwicke, 1820) was harvested for museums and collectors until it was presumed extinct worldwide for over a century since 1907. Recently in 2011, seven living individuals were rediscovered in Singapore with six relocated to a marine protected area in an effort to better monitor and protect the population, as well as to enhance external fertilisation success. To determine genetic diversity within the population, we sequenced the complete mitochondrial genomes and nuclear ribosomal DNA of these six individuals and found extremely limited variability in their genes. The low genetic diversity of this rediscovered population is confirmed by comparisons with close relatives of C. patera and could compromise the population's ability to recover from environmental and anthropogenic pressures associated with the highly urbanised coastlines of Singapore. This lack of resilience is compounded by severe predation which has been shrinking sponge sizes by up to 5.6% every month. Recovery of this highly endangered population may require ex situ approaches and crossbreeding with other populations, which are also rare.

A new species of Macandrewia Gray from a seamount near Yap Trench in the Western Pacific Ocean was described. Macandrewia yapensis sp. nov. is distinct from its congeners by possessing a foliate shape with contorted lamellae, tuberculiform terminations of desmas, and unique size of spicules. This is the third species of Macandrewia described from the Pacific Ocean. In addition, a partial sequence of COI gene was obtained from the new specimen and then it submitted to GenBank. Phylogenetic tree constructed with the partial COI sequences appears to exhibit a more congruent relationship with morphological data of macandrewiid species compared to 28S gene tree.

Benthic foraminiferal research in the North Pacific has a long history, with works published over a century ago providing important information about the taxonomy and distribution of morphospecies. These studies focused mainly on areas outside the Clarion-Clipperton Zone (CCZ). Our knowledge of foraminiferal faunas within the CCZ originates largely from recent baseline investigations related to likely future seabed mining of the polymetallic nodule deposits. These have revealed highly diverse assemblages of sediment-dwelling morphospecies among the meiofauna and macrofauna, as well as megafaunal xenophyophores and nodule-attached fauna. Morphological analyses have been complemented by metabarcoding studies that yielded even higher numbers of molecular species (Operational Taxonomic Units - OTUs). Monothalamids, the vast majority undescribed, constitute a substantial proportion of both morphological and molecular datasets, with multichambered agglutinated and calcareous foraminifera being less common. Their importance in this abyssal (>4,000 m depth) habitat likely reflects food limitation combined with carbonate dissolution close to and below the carbonate compensation depth. Literature records, supported in a few cases by genetic data, suggest that many morphospecies found in the CCZ have wide geographical distributions across the Pacific abyss and in other oceans. At smaller spatial scales (several 100s of kilometers) there is a general uniformity in assemblage composition. Nevertheless, many morphospecies are too rare to conclude anything about their geographical distributions. Similarly, the part played by benthic foraminifera in CCZ ecosystems is largely a matter of speculation, although their abundance across different size classes suggests that it is significant. Meiofauna-sized taxa that consume freshly-deposited organic detritus may be important in carbon cycling, particularly at the shallower, more eutrophic eastern end of the CCZ. Megafaunal xenophyophores can provide habitat structure for other organisms, potentially enhancing benthic biodiversity. Foraminifera of all sizes could be among the earliest recolonisers of disturbed or redeposited sediments. Their potential contributions in terms of both ecology and biodiversity make these protists significant members of benthic communities in the CCZ.

With 70% of the Earth’s surface covered in water, the marine ecosystem offers immense opportunities for drug discovery and development. Due to the decreasing rate of novel natural product discovery from terrestrial sources in recent years, many researchers are beginning to look seaward for breakthroughs in new therapeutic agents. As part of an ongoing marine drug discovery programme in Singapore, an integrated approach of combining metabolomic and genomic techniques were initiated for uncovering novel anti-quorum sensing molecules from bacteria associated with subtidal samples collected in the Singapore Strait. Based on the culture-dependent method, a total of 102 marine bacteria strains were isolated and the identities of selected strains were established based on their 16S rRNA gene sequences. About 5% of the marine bacterial organic extracts showed quorum sensing inhibitory (QSI) activity in a dose-dependent manner based on the Pseudomonas aeruginosa QS reporter system. In addition, the extracts were subjected to mass spectrometry-based molecular networking and the genome of selected strains were analysed for known as well as new biosynthetic gene clusters. This study revealed that using integrated techniques, coupled with biological assays, can provide an effective and rapid prioritization of marine bacterial strains for downstream large-scale culturing for the purpose of isolation and structural elucidation of novel bioactive compounds.

The endolithic and endopsammic habits in sponges promote similar morphologies and offer similar ecological niches of being protected and anchored. We assessed whether this also induces similar functions, i.e., whether the commonly endopsammic sponge Coelocarteria singaporensis (Carter, 1883) shares bioerosion capabilities with clionaid endopsammic sponges such as some Spheciospongia species, enabling it to inhabit and also to expand within calcareous substrates. We studied a range of traits that are commonly accepted as evidence for bioerosion. C. singaporensis has a globular or irregular body from which fistules arise, but the fistules never penetrated calcareous substrate, and while endopsammic specimens were able to agglutinate and incorporate particles, their bodies were not embedded within calcareous rock. Tough tissue filled small cavities in adjacent rock, but only in a few exceptions did we find sponge chips in it. We encountered the only indication for possible active bioerosion in the form of sponge scars and canals in some of the substrate the sponge touched or had embedded, but these areas lacked fresh erosion fissures and well-defined erosion scars and may have been made by other species. If C. singaporensis is able to bioerode, it does not seem to cut out chips to produce a regular shagreen pattern. The sponge clearly has the ability to insinuate into pre-existing cavities, but overall we regard the evidence for its bioerosion capability as circumstantial or unreliable. At this stage, we can neither confirm nor reject that this sponge may be able to bioerode calcareous material, but it appears to be unlikely.

The material for these volumes has been selected from the past twenty years' examination questions for graduate students at University of California at Berkeley, Columbia University, the University of Chicago, MIT, State University of New York at Buffalo, Princeton University and University of Wisconsin.

Despite alterations caused by anthropogenic activities in Singaporean coral reefs, the sponge communities are quite diverse andXestospongia testudinariais one of the most common sponge species. In the present study, we used 16S rRNA gene barcoded pyrosequencing to characterize and compare bacterial communities from different biotopes (sponge, seawater and sediment) and to identify dominant bacterial symbionts ofX. testudinariain a Singaporean coral reef ecosystem. Our results showed that biotope appears to affect the richness, composition and abundance of bacterial communities. Proteobacteria was the most abundant phylum in sediment and seawater whilst Chloroflexi was more abundant inX. testudinaria.Members of the order Caldilineales (fermentation of organic substrates), Chromatiales (purple sulphur bacteria), Rhodospirillales (purple non-sulphur bacteria) and Syntrophobacterales (sulphate-reducing bacteria) were relatively more abundant inX. testudinariasamples.

Invertebrates are a major reservoir for numerous cytotoxic compounds that are used to defence themselves against prey and adaptation towards the environment. Throughout the years, numerous studies discovered from sponge extracts were effective against a wide range of cancer cells. In this study, 23 sponges comprising of some 19 species were collected from Northeast Borneo. Sponges were treated and extracted using modified Folch extraction method, followed by cytotoxicity assay to determine their effectiveness against different colorectal cancer cells. From the results, Monanchora clathrate, Dysidea sp., and Jaspis sp. were found to possess different degrees of cytotoxicity against wide range of human colorectal cancer cell. Monanchora clathrate (KDT07), Dysidea sp. (KDT09), and Jaspis sp. (KDT18) are among the demosponges which possess significant cytotoxicity against colorectal cancer cell lines, including HCT116, LoVo, SW480, and SW620. Besides, we found that environmental factors tend to alter chemical yield from the different species under the same genera. Among them, KDT08 and KDT21 which fall under same genus Dysidea, yet possess insignificant cytotoxicity against colorectal cancer cells. This research article provides a preliminary test for cytotoxicity activity of a wide range of marine sponges. Throughout this study, acquired results could provide useful information to determine the worthiness to further isolate nor purify the nature product from these sponges.

Among marine demosponges (Porifera: Demospongiae), only representatives of the order Verongiida have been recognized to synthetize both biologically active substances as well as scaffolds-like fibrous skeletons made of structural aminopolysaccharide chitin. The unique 3D architecture of such scaffolds open perspectives for their applications in waste treatment, biomimetics and tissue engineering. Here, we focus special attention to the demosponge Pseudoceratina purpurea collected in the coastal waters of Singapore. For the first time the detailed description of the isolation of chitin from the skeleton of this sponge and its identification using diverse bioanalytical tools were carried out. Calcofluor white staining, FTIR analysis, electrospray ionization mass spectrometry (ESI-MS), SEM, and fluorescence microscopy as well as a chitinase digestion assay were applied in order to confirm with strong evidence the finding of alpha-chitin in the skeleton of P. purpurea. We suggest that the discovery of chitin within representatives of Pseudoceratinidae family is a perspective step in evaluation of these verongiid sponges as novel renewable sources for both chitin and biologically active metabolites, which are of prospective use for marine oriented biomedicine and pharmacology, respectively.

The Clarion-Clipperton Zone (CCZ) in the East Pacific is a vast region targeted for deep-sea mineral exploration, for which there are almost no published taxonomic data. Here we describe Plenaster craigi gen. nov. sp. nov. from depths of ∼4000 m in the eastern CCZ polymetallic nodule province. Despite over 40 years of intense exploration in the area, we reveal that P. craigi sp. nov. is the most abundant sponge and the most common metazoan encrusting on nodules in our study area at the eastern CCZ. It has a mean abundance of 15.3 ± 8.9 individuals per m2 across 11 stations in a 30 × 30 km study site nested within the Singapore exploration area. The white encrusting sponge is filled with spheroxyasters with occasional styles protruding the surface. Plenaster craigi sp. nov. is morphologically similar to genera from three different families in two orders: Timea (Timeidae; Tethyida); Hemiasterella and Leptosastra (Hemiasterellidae; Tethyida); and Paratimea (Stelligeridae; Axinellida). However, based on the molecular (COI and 28S) phylogenetic trees generated in this study, P. craigi sp. nov. was located in the Order Axinellida and appeared to be distant to Timea, Hemiasterella, Leptosastra, and Paratimea. We propose a new genus for our material to be placed provisionally in the family Stelligeridae, as it is the only family in the order Axinellida whose members possess euasters. This provisional placement may change when sequences of the type specimens of these genera and advanced phylogenetic reconstruction methods become available in the future. However, we have shown clearly that Plenaster gen. nov. is unique and distinct from all currently known taxa. Plenaster craigi sp. nov. being an abundant metazoan encrusting on nodule and easily identified filter-feeding animal is a potentially indicator species for future mining impacts in the eastern CCZ, and possibly across the entire CCZ. LSID: urn:lsid:zoobank.org:act:99D2DDBA-4643-4752-8C8A-AFF314E6B6E3