Hexactinellid Research Articles

Is the middle Cambrian Brooksella a hexactinellid sponge, trace fossil or pseudofossil?

First described as a medusoid jellyfish, the "star-shaped" Brooksella from the Conasauga shale Lagerstätten, Southeastern USA, was variously reconsidered as algae, feeding traces, gas bubbles, and most recently hexactinellid sponges. In this work, we present new morphological, chemical, and structural data to evaluate its hexactinellid affinities, as well as whether it could be a trace fossil or pseudofossil. External and cross-sectional surfaces, thin sections, X-ray computed tomography (CT) and micro-CT imaging, revealed no evidence that Brooksella is a hexactinellid sponge or a trace fossil. Although internally Brooksella contains abundant voids and variously orientated tubes consistent with multiple burrowing or bioeroding organisms, these structures have no relation to Brooksella's external lobe-like morphology. Furthermore, Brooksella has no pattern of growth comparable to the linear growth of early Paleozoic hexactinellids; rather, its growth is similar to syndepositional concretions. Lastly, Brooksella, except for its lobes and occasional central depression, is no different in microstructure to the silica concretions of the Conasauga Formation, strongly indicating it is a morphologically unusual endmember of the silica concretions of the formation. These findings highlight the need for thorough and accurate descriptions in Cambrian paleontology; wherein care must be taken to examine the full range of biotic and abiotic hypotheses for these compelling and unique fossils.

Designing Robust Superhydrophobic Materials for Inhibiting Nucleation of Clathrate Hydrates by Imitating Glass Sponges.

Superhydrophobic surfaces are suggested to deal with hydrate blockage because they can greatly reduce adhesion with the formed hydrates. However, they may promote the formation of fresh hydrate nuclei by inducing an orderly arrangement of water molecules, further aggravating hydrate blockage and meanwhile suffering from their fragile surfaces. Here, inspired by glass sponges, we report a robust anti-hydrate-nucleation superhydrophobic three-dimensional (3D) porous skeleton, perfectly resolving the conflict between inhibiting hydrate nucleation and superhydrophobicity. The high specific area of the 3D porous skeleton ensures an increase in terminal hydroxyl (inhibitory groups) content without damaging the superhydrophobicity, achieving the inhibition to fresh hydrates and antiadhesion to formed hydrates. Molecular dynamics simulation results indicate that terminal hydroxyls on a superhydrophobic surface can inhibit the formation of hydrate cages by disordering the arrangement of water molecules. And experimental data prove that the induction time of hydrate formation was prolonged by 84.4% and the hydrate adhesive force was reduced by 98.7%. Furthermore, this porous skeleton still maintains excellent inhibition and antiadhesion properties even after erosion for 4 h at 1500 rpm. Therefore, this research paves the way toward developing novel materials applied in the oil and gas industry, carbon capture and storage, etc.

Genome-centric view of the microbiome in a new deep-sea glass sponge species Bathydorus sp.

Sponges are widely distributed in the global ocean and harbor diverse symbiotic microbes with mutualistic relationships. However, sponge symbionts in the deep sea remain poorly studied at the genome level. Here, we report a new glass sponge species of the genus Bathydorus and provide a genome-centric view of its microbiome. We obtained 14 high-quality prokaryotic metagenome-assembled genomes (MAGs) affiliated with the phyla Nitrososphaerota, Pseudomonadota, Nitrospirota, Bdellovibrionota, SAR324, Bacteroidota, and Patescibacteria. In total, 13 of these MAGs probably represent new species, suggesting the high novelty of the deep-sea glass sponge microbiome. An ammonia-oxidizing Nitrososphaerota MAG B01, which accounted for up to 70% of the metagenome reads, dominated the sponge microbiomes. The B01 genome had a highly complex CRISPR array, which likely represents an advantageous evolution toward a symbiotic lifestyle and forceful ability to defend against phages. A sulfur-oxidizing Gammaproteobacteria species was the second most dominant symbiont, and a nitrite-oxidizing Nitrospirota species could also be detected, but with lower relative abundance. Bdellovibrio species represented by two MAGs, B11 and B12, were first reported as potential predatory symbionts in deep-sea glass sponges and have undergone dramatic genome reduction. Comprehensive functional analysis indicated that most of the sponge symbionts encoded CRISPR-Cas systems and eukaryotic-like proteins for symbiotic interactions with the host. Metabolic reconstruction further illustrated their essential roles in carbon, nitrogen, and sulfur cycles. In addition, diverse putative phages were identified from the sponge metagenomes. Our study expands the knowledge of microbial diversity, evolutionary adaption, and metabolic complementarity in deep-sea glass sponges.

Bio-inspired vertex modified lattice with enhanced mechanical properties

Conventional lattices usually exhibit tradeoff relations between their strength, deformation stability and energy absorption capacity. Here, inspired by the local structure characters of the skeletal system of deep-sea glass sponge, a new structure called vertex modified body-centered cubic (VM-BCC) lattice was proposed. The mechanical properties of the proposed lattices were compared with those of the conventional BCC, Octet and face-centered cubic (FCC) lattices. The results revealed that the BCC, Octet, and FCC lattices correspond to the highest deformation stability, the largest energy absorption and the highest strength among the three conventional lattices investigated, respectively, while the proposed VM-BCC lattice outperforms them all in each of the three properties. Remarkably, the proposed lattice made of stainless-steel possesses strength and energy-absorbing capacity close to that of lattices and foams made of titanium alloy. Moreover, a parametric numerical simulation study was carried out to ascertain the effect of the deviation coefficient, a geometric parameter of VM-BCC lattice on the mechanical properties and the deformation pattern. It indicates that the VM-BCC lattice with an appropriate deviation coefficient can effectively suppress the expansion of shear bands, resulting in high and stable stress response. This work proposes a novel bio-inspired lattice and enriches the design space for lightweight energy absorbers, which have prospective application potential in the fields of national defense, aerospace, navigation, and medical implants.

Crashworthiness design of a sponge-inspired multicell tube under axial crushing

A novel bio-inspired multicell tube (named UCGS), mimicking the unique double-diagonally reinforced configuration in the unit cell of glass sponge (GS), was proposed and fabricated by additive manufacturing. Crashworthiness analysis of UCGS was carried out via ABAQUS/Explicit and validated by quasi-static axial crushing tests. Due to its distinctive double-diagonal reinforcing strategy, the results demonstrated that UCGS had a high specific energy absorption (SEA) of up to 30.7 J/g, which was 32.2% to 53.1% higher than that of conventional multi-cell tubes and 7.7% to 28.1% higher than that of other bio-inspired tubes, respectively. Subsequently, the effects of geometric parameters and hierarchical designs on the energy absorption performance were investigated by numerical simulation. By choosing the proper geometric parameters and hierarchical design, the energy absorption capability of the presented bio-inspired multicell tube could be further increased, and the SEA was 3.3%–39% greater than the original design. Finally, a theoretical model was proposed to predict the mean crushing force, which was in good agreement with the numerical results. This study shed light on a deep understanding of the deformation mechanisms of bio-inspired tubes, and provided inspirations for designing and optimizing of energy absorber with high performance.

First record of the family Caprellidae (Amphipoda: Senticaudata) from the abyssal zone of the Bering Sea with description of a new species of Cercops

Three species of the amphipod family Caprellidae were collected in the area of the submarine Piip Volcano, the northwestern Bering Sea, during 75-th and 82-nd research cruises aboard the R/V Akademik M.A. Lavrentyev in 2016 and 2018 using the ROV Comanche-18. Two morphospecies of the genus Caprella (Caprellinae) were found on the Northern Summit of the Piip Volcano (depth 373 m) and on its northern slope (749–986 m). A new species, Cercops caecus Kireev and Golovan sp. nov. (Paracercopinae), was sampled in the abyssal zone adjacent to its southern slope (3362 m), where it was found on hydroids growing on a hexactinellid sponge. The new species differs from all other species of the genus by the lack of eyes and the presence of two pairs of gills in contrast to three paired gills found in the other congeners. This is the first record of an abyssal species of the subfamily Paracercopinae, whose other representatives are known from the shelf and the upper bathyal zones of the North Pacific, Arctic, and North Atlantic. This finding demonstrates the parallel processes of colonization of deep-sea habitats occurring in different subfamilies of Caprellidae. An updated diagnosis and a key to the Cercops species are provided. For the first time for Paracercopinae, data on the molecular marker (18S rRNA) was obtained.

Bio-inspired multi-cell tubular structures approaching ideal energy absorption performance

The energy absorption potential of conventional thin-walled tubes is compromised by the long-wavelength folding lobes, which result in a mean crushing force that is much smaller than their yield strength. Here, inspired by the characteristics of the skeletal of the glass sponge, a new thin-walled multi-cell tubular structure with modified face-centered cubic (MFCS) cross section is proposed. The compression behaviors and energy absorbing capacity of the proposed structure were compared with those of the traditional multi-cell tube through finite element simulation and experimental tests. Compared with the traditional multi-cell tubes, the proposed MFCS structure exhibits micro-folding lobes with shorter wavelength, resulting in larger energy absorption, higher energy absorption efficiency and a more stable and controllable deformation mode, with the mean crushing force almost reaching that of an ideal energy absorber. Moreover, the effects of the geometric coefficient of MFCS multi-cell tube on the energy absorption performance and deformation pattern were studied parametrically. Through the bionic design, extraordinary energy absorbing performance is achieved, providing guidance for future design of lightweight structures with unprecedented mechanical properties.

On the dissolution of sponge silica: Assessing variability and biogeochemical implications

The dissolution of the biogenic silica that constitutes the skeletons of silicifying organisms is an important mechanism for regenerating dissolved silicon in the ocean. The silica skeletons deposited to the seafloor after the organisms die keep dissolving until becoming definitively buried. The low dissolution rate of sponge skeletons compared to that of diatom skeletons favors their burial and makes sponges (Phylum Porifera) to function as important silicon sinks in the oceans. However, it remains poorly understood whether the large variety of siliceous skeletons existing in the Porifera involves similar variability in their dissolution rates, which would affect the general conceptualization of these organisms as silicon sinks. Herein we investigated kinetics of silica dissolution for major types of skeletons in the three siliceous lineages of Porifera, following standardized digestion conditions in 1% sodium carbonate with orbital agitation at 85°C. The results are compared with those of a previous study conducted under identical conditions, which considered diatom silica, sponge silica, and lithogenic silica. Unexpectedly, the silica of homoscleromorph sponges dissolved only a bit slower than that of freshly cultured diatoms and as fast as diatom earth. However, the rest of sponge skeletons were far more resistant, although with some differences: the isolated spicules of hexactinellid sponges dissolved slightly faster than when forming frameworks of fused spicules, being hexactinellid frameworks as resistant to dissolution as the silica of demosponges, irrespective of occurring in the form of isolated spicules or frameworks. The experiments also indicated that the complexation of sponge silica with aluminum and with chitin does not increase its resistance to dissolution. Because the rapidly-dissolving homoscleromorph sponges represent less than 1% of extant sponges, the sponge skeletons are still conceptualized as important silicon sinks due to their comparative resistance to dissolution. Yet, the turnover of silica into dissolved silicon will always be faster in environments dominated by hexactinellids with isolated spicules than in environments dominated by other hexactinellids and/or demosponges. We discuss whether the time required for a given silica type to completely dissolve in 1% sodium carbonate could be a predictor of its preservation ratio in marine sediments.

Optimization of a lattice structure inspired by glass sponge

The biomimetic design of engineering structures is based on biological structures with excellent mechanical properties, which are the result of billions of years of evolution. However, current biomimetic structures, such as ordered lattice materials, are still inferior to many biomaterials in terms of structural complexity and mechanical properties. For example, the structure of Euplectella aspergillum, a type of deep-sea glass sponge, is an eye-catching source of inspiration for biomimetic design, many researches have introduced similar architecture in cellular solids. However, guided by scientific theory, how to surpass the mechanical properties of E. aspergillum remains an unsolved problem. We proposed the lattice structure which firstly surpass the E. aspergillum mechanically. The lattice structure of the skeleton of E. aspergillum consists of vertically, horizontally, and diagonally oriented struts, which provide superior strength and flexural resistance compared with the conventional square lattice structure. Herein, the structure of E. aspergillum was investigated in detail, and by using the theory of elasticity, a lattice structure inspired by the biomimetic structure was proposed. The mechanical properties of the sponge-inspired lattice structure surpassed the sponge structure under a variety of loading conditions, and the excellent performance of this configuration was verified experimentally. The proposed lattice structure can greatly improve the mechanical properties of engineering structures, and it improves strength without much redundancy of material. This study achieved the first surpassing of the mechanical properties of an existing sponge-mimicking design. This design can be applied to lattice structures, truss systems, and metamaterial cells.

First record of sponge-associated deep-sea polychaete (Polynoidae: Bathymoorea) on the ultraslow-spreading Southwest Indian Ridge

We identified a rarely found deep-sea polynoid polychaete Bathymoorea, in association with a hexactinellid sponge (Dictyaulus sp.) during our marine mineral exploration expedition in the Southwest Indian Ridge (SWIR). The genus Bathymoorea appears to be restricted to the deep sea and currently includes two valid species described from the northeast Pacific region. The polychaete specimen was part of the megabenthos sample collected in a benthic sledge associated with a sponge from a water depth of 2358 m. The sponge-associated Bathymoorea is described and illustrated based on a single specimen and is the first occurrence of the genus Bathymoorea in the Southwest Indian Ocean. The morphological characteristics and phylogenetic analysis of Bathymoorea using Cytochrome C Oxidase subunit 1 (COI), 16S, and 18S gene sequences confirmed the monophyly clade for the SWIR specimen. Our finding extends the known geographical distribution of the genus Bathymoorea to the Indian Ocean.

Numerical analysis of low-speed impact response of sandwich panels with bio-inspired diagonal-enhanced square honeycomb core

The diagonal-enhanced square grid configuration inspired by glass sponge has great potential in mechanics, with geometries serving as honeycomb cores for sandwich panels, which can improve the structure’s energy absorption capabilities. Modeling the hexagonal honeycomb core (HHC) sandwich panels, a finite element numerical model for low-speed impact of sandwich panels with high accuracy is proposed, and low-speed impact response of bio-inspired diagonal-enhanced square honeycomb core (BSHC) sandwich panels is studied. The impact response of BSHC sandwich panels, Hexagonal honeycomb core (HHC) sandwich panels and ordinary square honeycomb core (OSHC) sandwich panels were studied with the same relative densities and the same face-sheets. BSHC can lead to significantly enhanced the peak loads and stiffness of the sandwich panels. BSHC sandwich panels not only have excellent energy absorption performance, but also outperform HHC sandwich panels in terms of resistance to impact deformation. BSHC can transfer dynamic loads from the front face-sheet to the back face-sheet efficiently without stress concentration in the core itself. A theoretical analysis of the energy absorption capacity of the BSHCs and HHC were performed to illustrate the energy absorption mechanism. In addition, the peak load and contact energy of BSHC sandwich panels and HHC sandwich panels were theoretically predicted under low-speed impact.

Comprehensive Computational Model for Coupled Fluid Flow, Mass Transfer, and Light Supply in Tubular Photobioreactors Equipped with Glass Sponges

The design and optimization of photobioreactor(s) (PBR) benefit from the development of robust and quantitatively accurate computational fluid dynamics (CFD) models, which incorporate the complex interplay of fundamental phenomena. In the present work, we propose a comprehensive computational model for tubular photobioreactors equipped with glass sponges. The simulation model requires a minimum of at least three submodels for hydrodynamics, light supply, and biomass kinetics, respectively. First, by modeling the hydrodynamics, the light–dark cycles can be detected and the mixing characteristics of the flow (besides the mass transport) can be analyzed. Second, the radiative transport model is deployed to predict the local light intensities according to the wavelength of the light and scattering characteristics of the culture. The third submodel implements the biomass growth kinetic by coupling the local light intensities to hydrodynamic information of the CO2 concentration, which allows to predict the algal growth. In combination, the novel mesoscopic simulation model is applied to a tubular PBR with transparent walls and an internal sponge structure. We showcase the coupled simulation results and validate specific submodel outcomes by comparing the experiments. The overall flow velocity, light distribution, and light intensities for individual algae trajectories are extracted and discussed. Conclusively, such insights into complex hydrodynamics and homogeneous illumination are very promising for CFD-based optimization of PBR.

A new report on the deep-sea sponge-associated Spongicoloides weijiaensis Xu, Zhou & Wang, 2017 (Decapoda: Spongicolidae) from the Southwest Indian Ocean Ridge

The sponge-associated benthic shrimp Spongicoloides weijiaensis Xu, Zhou & Wang, 2017 is reported for the first time from the Southwest Indian Ridge (SWIR). A single female specimen of S.weijiaensis was associated with the hexactinellid sponge belonging to Dictyaulus sp. that was collected using a benthic sledge from the southwest Indian Ridge at a water depth of 2358 m. The spongicolid shrimp is reported using both classical taxonomic and molecular tools (cytochrome c oxidase subunit 1-COI). The S. weijiaensis specimen from the SWIR appears to represent a morphological variant that has pigmented eyes, telson with thirteen spines, and a broadly rounded setiferous posterior margin. This new report at a latitude of nearly 26° South on the seamount provides the first Mid Ocean Ridge sector record for stenopodidean shrimp known to date.

Lightweight lattice-based skeleton of the sponge Euplectella aspergillum: On the multifunctional design

The glass sponge, Euplectella aspergillum, possesses a lightweight, silica spicule-based, cylindrical lattice-like skeleton, representing an excellent model system for bioinspired lattices. Previous analysis suggested that the E. aspergillum's skeletal lattice exhibits improved buckling resistance and suppressed vortex shedding. How the sponge's skeletal lattice with diagonally-oriented reinforcing bundle of fused spicules and the ridge system behaves under different loading conditions and achieves dual mechanical and fluidic transport performance requires further investigation. Here, we first quantified the structural descriptors such as length and thickness of the bundles of fused spicules and hole opening diameter of the sponge skeletons with and without the soft tissue covered. Secondly, parametric modeling and simulations of the sponge lattice in comparison with other bioinspired designs under different loading conditions were implemented to obtain the structure-mechanical property relationship. Our results reveal that the double-diagonal reinforcements of the E. aspergillum's lattices show i) tendency to maximize the torsional rigidity in comparison to longitudinal and radial modulus and flexural rigidity, and ii) independency of mechanical properties on the diagonal spacing, leaving freedom to control the hole-opening position for the sponge's fluid transport. Furthermore, our coupled fluid-mechanical simulations suggest that the ridge system spiraling the cylindrical lattice simultaneously improves the radial stiffness and fluid permeability. Finally, we discuss the general mechanical strategies and design flexibility in the sponge's skeletal lattice. Our work provides understanding of the mechanical and functional trade-offs in E. aspergillum's skeletal lattice which may shed light on the design of lightweight tubular lattices.

Biodiversity, environmental drivers, and sustainability of the global deep-sea sponge microbiome

In the deep ocean symbioses between microbes and invertebrates are emerging as key drivers of ecosystem health and services. We present a large-scale analysis of microbial diversity in deep-sea sponges (Porifera) from scales of sponge individuals to ocean basins, covering 52 locations, 1077 host individuals translating into 169 sponge species (including understudied glass sponges), and 469 reference samples, collected anew during 21 ship-based expeditions. We demonstrate the impacts of the sponge microbial abundance status, geographic distance, sponge phylogeny, and the physical-biogeochemical environment as drivers of microbiome composition, in descending order of relevance. Our study further discloses that fundamental concepts of sponge microbiology apply robustly to sponges from the deep-sea across distances of >10,000 km. Deep-sea sponge microbiomes are less complex, yet more heterogeneous, than their shallow-water counterparts. Our analysis underscores the uniqueness of each deep-sea sponge ground based on which we provide critical knowledge for conservation of these vulnerable ecosystems.

Bionic design and performance research of tracheal stent based on shape memory polycaprolactone

Trachea injury caused by tracheomalacia, stenosis or atresia can result in severe dyspnea, even asphyxia. With the development of trachea reconstruction technology, trachea stents have become an alternative treatment method. Here, we fabricated a kind of shape memory PCL/Fe3O4 composites (SMPC-PCL) by mixing different weight fractions of benzoyl peroxide and Fe3O4 nanoparticles. The addition of magnetic nanoparticles endowed SMPC-PCL with the capability of remote non-contact actuation, which exhibited unique advantages in minimally invasive implantation and adaptive ability. Further, based on fully observing the unique reticular structure of glass sponges, two types of biomimetics stents were designed and fabricated, and the mechanical properties were thoroughly investigated by experiments and finite element analysis. The minimally invasive implant performance and biological characterization were carried out to evaluate its availability. The excellent mechanical properties, minimally invasive implant performance and biological properties suggest the application potential in tracheal stents.

Preparation and characterization of a self-crosslinking sodium alginate-bioactive glass sponge.

In this research, bioactive glass particles prepared by the reactive flash nanoprecipitation method (RFNP-BG particles) are used to crosslink sodium alginate to prepare biological sponges (SA-BG sponges) by freeze-drying. An experiment for the cross-linking mechanism confirms that the continuous release of Ca2+ from RFNP-BG is promoted by the crosslinking reaction and in turn leads to the gelation process of SA. Bioactive glass particles not only provide Ca2+ for the crosslinking of sodium alginate, but also enhance the mechanical properties of the SA-BG sponges. The results show that the elastic modulus of the SA-BG sponges increases from 0.026 MPa to 0.641 MPa, and the resistance to external force deformation is greatly improved; the thermal decomposition temperature increases from 105°C to 166°C; compared with a pure SA sponge, the water resistance is significantly improved. In vitro cell experiments show that the SA-BG sponges have a certain adverse effect on cell proliferation, but it is in an acceptable range. qPCR results show that the SA-BG sponges have a certain beneficial effect on promoting osteogenic gene expression. The SA-BG sponges have great application potential in the fields of medicine, hemostasis, and wound closure.

A New Method of Determining Glass Sponge Reef Adaptive Management Zones for the Hecate Strait and Queen Charlotte Sound Marine Protected Area

The world’s largest living glass sponge reefs, located in the Hecate Strait and Queen Charlotte Sound off British Columbia, are impacted by bottom contact fishing gear. The existing Adaptive Management Zones (AMZs) for the protection of these reefs were determined by considering the potential exposure of glass sponges to suspended sediment due to mobile bottom-contact fishing, but without considering their pumping arrest threshold concentrations. Here, we develop a new method that uses a sediment transport model under horizontally variable near-bottom currents and newly available sponge reef pumping arrest thresholds to determine the size and shape of AMZ for the northern reefs in the Hecate Strait and Queen Charlotte Sound Marine Protected Area. The resulting AMZ is larger than the existing AMZ due to the observation that the largest currents are not always in the direction of the dominant tidal flows, the introduction of the new pumping arrest threshold, and the inclusion of a background sediment concentration. The new AMZ boundary could provide more adequate protection for the glass sponge reefs from the effects of sedimentation induced by mobile, bottom-contact fishing activity. The new method is applicable to other glass sponge reefs in British Columbia waters.

The Comparative approach to bio-inspired design: integrating biodiversity and biologists into the design process.

Biodiversity provides a massive library of ideas for bio-inspired design, but the sheer number of species to consider can be daunting. Current approaches for sifting through biodiversity to identify relevant biological models include searching for champion adapters that are particularly adept at solving a particular design challenge. While the champion adapter approach has benefits, it tends to focus on a narrow set of popular models while neglecting the majority of species. An alternative approach to bio-inspired design is the comparative method, which leverages biodiversity by drawing inspiration across a broad range of species. This approach uses methods in phylogenetics to map traits across evolutionary trees and compare trait variation to infer structure-function relationships. Although comparative methods have not been widely used in bio-inspired design, they have led to breakthroughs in studies on gecko-inspired adhesives and multifunctionality of butterfly wing scales. Here we outline how comparative methods can be used to complement existing approaches to bioinspired design, and we provide an example focused on bio-inspired lattices, including honeycomb and glass sponges. We demonstrate how comparative methods can lead to breakthroughs in bio-inspired applications as well as answer major questions in biology, which can strengthen collaborations with biologists and produce deeper insights into biological function.

Two New Species and One New Genus of Glass Sponges (Hexactinellida: Euplectellidae and Euretidae), From a Transect on a Seamount in the Northwestern Pacific Ocean

Hexactinellid sponges often form structural habitats for other organisms and thus support high biodiversity. Two representative morphotypes of hexactinellid sponges were sampled by a remotely operated vehicle along a transect (depths of 2377–2758 m) on the Ko-Hakucho Guyot in the northwestern Pacific Ocean, both new to science. One new species,Flavovirens hemiglobusgen. et sp. nov., which is pedunculate and bears the main choanosomal spicules of diactins, is clearly attributed to the euplectellid subfamily Bolosominae. Its set of microscleres present (namely, predominating oxyhexasters and discasters, and rare discohexasters and staurodiscs) characterizes it as a new genus. The other new species,Chonelasma tyloscopulatumsp. nov., which is funnel in form without dichotomous branching tubes or lateral oscula and has firm body walls supported by a three-layered dictyonal framework, is clearly attributed to the euretid genusChonelasma(subfamily Chonelasmatinae). Its presence of surface pentactins, two types of scopules, and both oxy- and disco-tipped hexasters or hemihexasters as common microscleres, characterizes it as a new species. The placements are also supported by molecular phylogenetic evidence from nuclear 18S rDNA and 28S rDNA, and mitochondrial 16S rDNA and cytochrome c oxidase subunit I (COI) gene. More sampling efforts should be conducted to improve the understanding of the biodiversity of deep-sea seamount sponges.