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Henry M Reiswig - One of the best experts on this subject based on the ideXlab platform.
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report of cladorhiza bathycrinoides koltun demospongiae from north america and a new species of farrea Hexactinellida among sponges from cordell bank california
Zootaxa, 2020Co-Authors: Henry M ReiswigAbstract:A small collection of five Sponges made by E/V Nautilus on Cordell Bank National Marine Sanctuary, California, include the first report of the crinorhyzid Cladorhiza bathycrinoides Koltun off North America and a new species of Hexactinellida, Farrea. cordelli n. sp. The other three sponges in the collection are known to occur off the surrounding North-East Pacific coast, but new geographic or depth distributions are reported for these.
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four new species of Hexactinellida porifera and a name replacement from the ne pacific
Zootaxa, 2018Co-Authors: Henry M ReiswigAbstract:Four new species of Hexactinellida are described from the northwest coast of North America. Two northern ones from bottom longline sablefish traps set on Bowie Seamount off northwest Canada are Pinulasma bowiensis and Rhabdocalyptus trichotis. Two southern forms picked by ROV from the wreck of USS Independence off San Francisco, California are Staurocalyptus pamelaturnerae and Hyalascus farallonensis. A fifth specimen from the southern site is considered conspecific with the junior homonym Farrea aculeata Schulze, and allowed renaming of that species as Farrea schulzei. These additions bring the number of Hexactinellida known from the area (30o-90o N) to 62 species.
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an integrative systematic framework helps to reconstruct skeletal evolution of glass sponges porifera Hexactinellida
Frontiers in Zoology, 2017Co-Authors: Martin Dohrmann, Andrzej Pisera, Henry M Reiswig, Michelle Kelly, Christopher Kelley, John N A HooperAbstract:Glass sponges (Class Hexactinellida) are important components of deep-sea ecosystems and are of interest from geological and materials science perspectives. The reconstruction of their phylogeny with molecular data has only recently begun and shows a better agreement with morphology-based systematics than is typical for other sponge groups, likely because of a greater number of informative morphological characters. However, inconsistencies remain that have far-reaching implications for hypotheses about the evolution of their major skeletal construction types (body plans). Furthermore, less than half of all described extant genera have been sampled for molecular systematics, and several taxa important for understanding skeletal evolution are still missing. Increased taxon sampling for molecular phylogenetics of this group is therefore urgently needed. However, due to their remote habitat and often poorly preserved museum material, sequencing all 126 currently recognized extant genera will be difficult to achieve. Utilizing morphological data to incorporate unsequenced taxa into an integrative systematics framework therefore holds great promise, but it is unclear which methodological approach best suits this task. Here, we increase the taxon sampling of four previously established molecular markers (18S, 28S, and 16S ribosomal DNA, as well as cytochrome oxidase subunit I) by 12 genera, for the first time including representatives of the order Aulocalycoida and the type genus of Dactylocalycidae, taxa that are key to understanding hexactinellid body plan evolution. Phylogenetic analyses suggest that Aulocalycoida is diphyletic and provide further support for the paraphyly of order Hexactinosida; hence these orders are abolished from the Linnean classification. We further assembled morphological character matrices to integrate so far unsequenced genera into phylogenetic analyses in maximum parsimony (MP), maximum likelihood (ML), Bayesian, and morphology-based binning frameworks. We find that of these four approaches, total-evidence analysis using MP gave the most plausible results concerning congruence with existing phylogenetic and taxonomic hypotheses, whereas the other methods, especially ML and binning, performed more poorly. We use our total-evidence phylogeny of all extant glass sponge genera for ancestral state reconstruction of morphological characters in MP and ML frameworks, gaining new insights into the evolution of major hexactinellid body plans and other characters such as different spicule types. Our study demonstrates how a comprehensive, albeit in some parts provisional, phylogeny of a larger taxon can be achieved with an integrative approach utilizing molecular and morphological data, and how this can be used as a basis for understanding phenotypic evolution. The datasets and associated trees presented here are intended as a resource and starting point for future work on glass sponge evolution.
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Mediterranean hexactinellid sponges, with the description of a new Sympagella species (Porifera, Hexactinellida)
Journal of the Marine Biological Association of the UK, 2015Co-Authors: Nicole Boury-esnault, Henry M Reiswig, Jean Vacelet, Maïa Fourt, Ricardo Aguilar, Pierre ChevaldonneAbstract:An overview is proposed of the hexactinellid sponge fauna of the Mediterranean Sea, including the description of a new species of Sympagella, S. delauzei sp. nov., collected by ROV during the exploration of deep-sea canyons of the NW Mediterranean and of deep banks and seamounts of the Alboran Sea. The type species of Sympagella, S. nux, is redescribed from specimens from the type locality. An 18S rDNA sequence of the new species was obtained and included in a phylogenetic tree of related hexactinellids. Some modifications to the classification of Rossellidae are proposed according to the new morphological and molecular data obtained during this study: the genera Caulophacus, and Caulophacella are accordingly moved from Rossellinae to Lanuginellinae.
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first lanuginellinae porifera Hexactinellida rossellidae from the ne pacific and first species of doconesthes from the pacific ocean
Zootaxa, 2015Co-Authors: Henry M ReiswigAbstract:A new sac-shaped hexactinellid collected from western Canada bearing long lateral prostal spicules was first thought to be a typical Rossellinae. Subsequent examination of its spiculation proved it to have distinctive strobiloplumicomes, typical of the subfamily Lanuginellinae. Other spicules showed it to be a member of the monospecific genus Doconesthes , known previously only from the North Atlantic Ocean. The new species described here as Doconesthes dustinchiversi is only the second known species of the genus and the first to be found in the Pacific Ocean.
Martin Dohrmann - One of the best experts on this subject based on the ideXlab platform.
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compositional and quantitative insights into bacterial and archaeal communities of south pacific deep sea sponges demospongiae and Hexactinellida
Frontiers in Microbiology, 2020Co-Authors: Dirk Erpenbeck, Pedro Martinez Arbizu, Georg Steinert, Kathrin Busch, Kristina Bayer, Sahar Kodami, Michelle Kelly, Sadie Mills, Martin DohrmannAbstract:In the present study, we profiled bacterial and archaeal communities from 13 phylogenetically diverse deep-sea sponge species (Demospongiae and Hexactinellida) from the South Pacific by 16S rRNA-gene amplicon sequencing. Additionally, the associated bacteria and archaea were quantified by real-time qPCR. Our results show that bacterial communities from the deep-sea sponges are mostly host-species specific similar to what has been observed for shallow-water demosponges. The archaeal deep-sea sponge community structures are different from the bacterial community structures in that they are almost completely dominated by a single family, which are the ammonia-oxidizing genera within the Nitrosopumilaceae. Remarkably, the archaeal communities are mostly specific to individual sponges (rather than sponge-species), and this observation applies to both hexactinellids and demosponges. Finally, archaeal 16s gene numbers, as detected by quantitative real-time PCR, were up to three orders of magnitude higher than in shallow-water sponges, highlighting the importance of the archaea for deep-sea sponges in general.
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a new glass sponge genus Hexactinellida euplectellidae from abyssal depth of the yap trench northwestern pacific ocean
Zootaxa, 2019Co-Authors: Chengcheng Shen, Martin Dohrmann, Dongsheng Zhang, Chunsheng WangAbstract:In this article we report on a hexactinellid sponge new to science, Rhizophyta yapensis gen. et sp. nov., which was collected from the Yap Trench in the northwestern Pacific Ocean at an abyssal depth of 4159-4779 m. Its fungus-like body form with long peduncle and absence of hypodermalia suggest placement within the euplectellid subfamily Bolosominae Tabachnick, 2002, whereas molecular phylogenetic evidence suggests that it is sister to all remaining Euplectellidae Gray, 1867. Its rhizophytous method of attachment to the substrate, hitherto unknown from bolosomine Euplectellidae, a veil of pentactins covering the peduncle, and the presence of toothed discohexasters as the only type of microscleres, clearly characterize it as a new genus. The intraspecific divergence between holotype and paratypes of the new species is examined with both morphological and molecular approaches. This report represents the first record of a hexactinellid sponge from the Yap Trench.
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an integrative systematic framework helps to reconstruct skeletal evolution of glass sponges porifera Hexactinellida
Frontiers in Zoology, 2017Co-Authors: Martin Dohrmann, Andrzej Pisera, Henry M Reiswig, Michelle Kelly, Christopher Kelley, John N A HooperAbstract:Glass sponges (Class Hexactinellida) are important components of deep-sea ecosystems and are of interest from geological and materials science perspectives. The reconstruction of their phylogeny with molecular data has only recently begun and shows a better agreement with morphology-based systematics than is typical for other sponge groups, likely because of a greater number of informative morphological characters. However, inconsistencies remain that have far-reaching implications for hypotheses about the evolution of their major skeletal construction types (body plans). Furthermore, less than half of all described extant genera have been sampled for molecular systematics, and several taxa important for understanding skeletal evolution are still missing. Increased taxon sampling for molecular phylogenetics of this group is therefore urgently needed. However, due to their remote habitat and often poorly preserved museum material, sequencing all 126 currently recognized extant genera will be difficult to achieve. Utilizing morphological data to incorporate unsequenced taxa into an integrative systematics framework therefore holds great promise, but it is unclear which methodological approach best suits this task. Here, we increase the taxon sampling of four previously established molecular markers (18S, 28S, and 16S ribosomal DNA, as well as cytochrome oxidase subunit I) by 12 genera, for the first time including representatives of the order Aulocalycoida and the type genus of Dactylocalycidae, taxa that are key to understanding hexactinellid body plan evolution. Phylogenetic analyses suggest that Aulocalycoida is diphyletic and provide further support for the paraphyly of order Hexactinosida; hence these orders are abolished from the Linnean classification. We further assembled morphological character matrices to integrate so far unsequenced genera into phylogenetic analyses in maximum parsimony (MP), maximum likelihood (ML), Bayesian, and morphology-based binning frameworks. We find that of these four approaches, total-evidence analysis using MP gave the most plausible results concerning congruence with existing phylogenetic and taxonomic hypotheses, whereas the other methods, especially ML and binning, performed more poorly. We use our total-evidence phylogeny of all extant glass sponge genera for ancestral state reconstruction of morphological characters in MP and ML frameworks, gaining new insights into the evolution of major hexactinellid body plans and other characters such as different spicule types. Our study demonstrates how a comprehensive, albeit in some parts provisional, phylogeny of a larger taxon can be achieved with an integrative approach utilizing molecular and morphological data, and how this can be used as a basis for understanding phenotypic evolution. The datasets and associated trees presented here are intended as a resource and starting point for future work on glass sponge evolution.
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symplectella rowi porifera Hexactinellida lyssacinosida is a rossellid not a euplectellid
Journal of the Marine Biological Association of the United Kingdom, 2016Co-Authors: Martin DohrmannAbstract:The monospecific hexactinellid sponge genus Symplectella endemic to New Zealand waters was originally assigned to family Rossellidae within the order Lyssacinosida (subclass Hexasterophora), although affinities to family Euplectellidae were also noted. Seventy-eight years later, the genus was transferred to Euplectellidae (subfamily Corbitellinae) on rather subjective grounds. Here, I test these two competing taxonomic hypotheses with molecular phylogenetic methods and demonstrate that Symplectella rowi is indeed a rossellid, as was originally suggested. The genus is officially transferred back to Rossellidae (subfamily Rossellinae), which represents another small step towards a more natural classification system of glass sponges.
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symplectella rowi porifera Hexactinellida lyssacinosida is a rossellid not a euplectellid j mar biol ass u k in press
2015Co-Authors: Martin DohrmannAbstract:The monospecific hexactinellid sponge genus Symplectella endemic to New Zealand waters was originally assigned to family Rossellidae within the order Lyssacinosida (subclass Hexasterophora), although affinities to family Euplectellidae were also noted. Seventy-eight years later, the genus was transferred to Euplectellidae (subfamily Corbitellinae) on rather subjective grounds. Here, I test these two competing taxonomic hypotheses with molecular phylogenetic methods and demonstrate that Symplectella rowi is indeed a rossellid, as was originally suggested. The genus is officially transferred back to Rossellidae (subfamily Rossellinae), which represents another small step towards a more natural classification system of glass sponges.
Dorte Janussen - One of the best experts on this subject based on the ideXlab platform.
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oldest known fossil of rossellids Hexactinellida porifera from the ordovician silurian transition of anhui south china
PalZ, 2019Co-Authors: Dorte Janussen, Renbin 詹仁斌 Zhan, Joachim ReitnerAbstract:Rossellids are geographically widespread in the modern deep-water sponge community. They are referred to Lyssacinosida, characterized by hypodermal pentactines and choanosomal megascleres of hexactines and diactines or the latter only. The fossil records of rossellids are usually found in the Cenozoic, with the earliest existence known from the Upper Cretaceous, later than the molecular phylogenetic result. A new lyssacinosan hexactinellid, Palaeorossella sinensis gen. et sp. nov., is described from the uppermost Ordovician of Anhui, South China. The sponge shows a saccular, globular or oval form with relatively thick wall. The skeleton is lyssacine type mainly composed of hexactines and stauractines, with the outer margin reinforced by hypodermal pentactines, which usually protrude the periphery as prostalia lateralia. The new species is well-preserved with typical hypodermal and prostalia pentactines as well as an articulated skeleton, giving some tentative insights into the affinity between the new species and other taxa in Rossellidae. It represents the oldest record of rossellids, providing new information for understanding the phylogeny of rossellids and on the evolution of modern Hexactinellida.
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two new species of sympagella porifera Hexactinellida rossellidae collected from the clarion clipperton zone east pacific
Zootaxa, 2018Co-Authors: Sascha Herzog, Diva J Amon, Craig R Smith, Dorte JanussenAbstract:Two new Hexactinellida species from the Clarion-Clipperton Zone (CCZ) in the East Pacific Ocean are described. They are the first described representatives of the genus Sympagella in this region. The new sponges were collected in 2013 during the ABYSSLINE Project´s first cruise, AB01, on board the RV Melville . The CCZ is known for its polymetallic nodules but megafaunal biodiversity is still poorly understood. Our findings suggest that the poriferan fauna of the eastern CCZ is both species rich and inadequately known, and that substantially more sampling and taxonomic studies of the CCZ sponge fauna are required to establish a megafaunal biogeography and evaluate potential extinction risks resulting from polymetallic-nodule mining.
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first insights into the phylogeny of deep sea glass sponges Hexactinellida from polymetallic nodule fields in the clarion clipperton fracture zone ccfz northeastern pacific
Hydrobiologia, 2018Co-Authors: Daniel Kersken, Dorte Janussen, Kevin M Kocot, Tilman Schell, Markus Pfenninger, Pedro Martinez ArbizuAbstract:Glass sponges represent a dominant group of megabenthic deep-sea fauna and play a key role in benthic deep-sea ecosystems. Especially in the Clarion-Clipperton Fracture Zone (CCFZ), a potential deep-sea mining area, they grow on polymetallic nodules or on the surrounding sediment. We investigate hexactinellids from the CCFZ to understand the ecological aspects of deep-sea mining and support the development of future pre-mining risk assessments and monitoring actions. Therefore, this study is published as part of a series of studies, all focusing on deep-sea glass sponges from the CCFZ. Resolving genetic relationships between species is still a fundamental as well as challenging task. Especially understudied groups mostly lack resolution. Combining results derived from taxonomic and phylogenetic data gives deeper insights into glass sponge relationships. Here, we present (1) a set of new primers for sequencing mitochondrial 16S rDNA as well as nuclear 18S and 28S rDNA of glass sponges, (2) first DNA sequencing data for 6 hexactinellid genera and 19 species, as well as (3) the most comprehensive phylogenetic tree of hexactinellid sponges to date including data available from previous studies.
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deep sea glass sponges Hexactinellida from polymetallic nodule fields in the clarion clipperton fracture zone ccfz northeastern pacific part ii hexasterophora
Marine Biodiversity, 2017Co-Authors: Daniel Kersken, Dorte Janussen, Pedro Martinez ArbizuAbstract:The Clarion-Clipperton Fracture Zone (CCFZ) in the northeastern Pacific is a potential area for deep-sea mining, comprises the worldwide largest polymetallic nodule fields and is one of the most difficult to sample and thus unknown ecosystems. Glass sponges (Hexactnellida) represent a main group of benthic deep-sea megafauna, especially hexasterophorid sponges, but only few studies have been published so far. This is the first study focusing on the taxonomy of hexasterophorid sponges from polymetallic nodule fields in the CCFZ and includes descriptions of eight known and six new species: Hyalostylus microfloricomus sp. nov.; Hyalostylus schulzei sp. nov.; Docosaccus nidulus sp. nov.; Holascus spinosus sp. nov.; Caulophacus (Caulophacus) wilsoni sp. nov.; and Chonelasma bispinula sp. nov.
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Hexactinellida porifera from the drake passage southern ocean with a description of three new species
Zootaxa, 2016Co-Authors: Claire Goodwin, Dorte Janussen, Christian Gocke, Jade Berman, Katharine R HendryAbstract:The Drake Passage has over 20 seamounts and ridges but it is notorious for large waves, fierce storms and strong currents that make benthic sampling difficult and therefore infrequent. Seamounts often have diverse sponge communities and may have high levels of endemism. Hexactinellida from Sars Seamount, an area in which the sponges had not previously been studied, and the Shackleton fracture zone were collected on a research cruise by the Nathaniel B Palmer in the Drake Passage, Southern Ocean. In total, from all cruise stations, 103 specimens of Hexactinellida were collected, however many appeared to be fragments of dead specimens and could not be identified due to missing microscleres. From Sars Seamount 127 sponge specimens were taken and from the Shackleton Fracture Zone 76 sponge specimens were taken; of these 36 and 16 respectively were Hexactinellida. From these two areas three new species of Hexactinellida are described: Doconesthes robinsoni sp. nov., Sympagella walleri sp. nov. and Caulophacus palmeri sp. nov and new records were made of Aulocalyx irregularis and Rossella antarctica .
Werner E G Muller - One of the best experts on this subject based on the ideXlab platform.
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bio sintering bio fusion of silica in sponge spicules
Advanced Engineering Materials, 2012Co-Authors: Xiaohong Wang, Ute Schlosmacher, Heinz C Schroder, Klaus Peter Jochum, Matthias Wiens, Werner E G MullerAbstract:The synthesis of siliceous spicules in both demosponges and hexactinellids is enzymatically driven via silicatein. This enzyme exists both intra-spicularly and in the extra-spicular space. It catalyzes the formation of bio-silica constituting the silica lamellae that are formed during the appositional (layer-by-layer) growth of the spicules. The extent of (bio-silica forming) activity of silicatein from the demosponge Suberites domuncula measured in vitro reflects the amount of bio-silica required for the formation of spicules in vivo. It is shown that during growth and maturation of the spicules in demosponges a bio-fusion process occurs that results in an intra-spicular sintering of the silica lamellae to form compact silica rods. The morphological characterization of the globular asters (microscleres) from the demosponge Geodia cydonium revealed that these spherical spicules are formed from a tuft of silicatein filaments which radiate from a common origin. While in demosponges a complete intra-spicular bio-sintering/bio-fusion process occurs, this process is incomplete in hexactinellid spicules. There, only the most inner lamellae of the spicules fuse leaving the more peripheral silica lamellae separate. However, within this class of sponges several families (example Euplectella aspergillum) show a bio-sintering process between individual spicules. There, bio-silica is secondarily deposited onto mature spicules, giving rise to an ordered array of bio-silica bridges. Furthermore we report that for the formation of the strong and stiff bio-silica skeleton of sponges a hardening process is required that is (presumable) driven by cell-membrane bound aquaporin channels which allow the removal of water, released during the bio-silica polycondensation reaction.
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the largest bio silica structure on earth the giant basal spicule from the deep sea glass sponge monorhaphis chuni
Evidence-based Complementary and Alternative Medicine, 2011Co-Authors: Xiaohong Wang, Heinz C Schroder, Lu Gan, Klaus Peter Jochum, Werner E G MullerAbstract:The depth of the ocean is plentifully populated with a highly diverse fauna and flora, from where the Challenger expedition (1873–1876) treasured up a rich collection of vitreous sponges [Hexactinellida]. They have been described by Schulze and represent the phylogenetically oldest class of siliceous sponges [phylum Porifera]; they are eye-catching because of their distinct body plan, which relies on a filigree skeleton. It is constructed by an array of morphologically determined elements, the spicules. Later, during the German Deep Sea Expedition “Valdivia” (1898-1899), Schulze could describe the largest siliceous hexactinellid sponge on Earth, the up to 3 m high Monorhaphis chuni, which develops the equally largest bio-silica structures, the giant basal spicules (3 m × 10 mm). With such spicules as a model, basic knowledge on the morphology, formation, and development of the skeletal elements could be elaborated. Spicules are formed by a proteinaceous scaffold which mediates the formation of siliceous lamellae in which the proteins are encased. Up to eight hundred 5 to 10 μm thick lamellae can be concentrically arranged around an axial canal. The silica matrix is composed of almost pure silicon and oxygen, providing it with unusual optophysical properties that are superior to those of man-made waveguides. Experiments indicated that the spicules function in vivo as a nonocular photoreception system. In addition, the spicules have exceptional mechanical properties, combining mechanical stability with strength and stiffness. Like demosponges the hexactinellids synthesize their silica enzymatically, via the enzyme silicatein. All these basic insights will surely contribute also to a further applied utilization and exploration of bio-silica in material/medical science.
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bio sintering processes in hexactinellid sponges fusion of bio silica in giant basal spicules from monorhaphis chuni
Journal of Structural Biology, 2009Co-Authors: Werner E G Muller, Alexandra Boreiko, Ute Schlosmacher, Zaklina Burghard, Anatoli Krasko, Joachim Bill, Xiaohong Wang, Heinz C SchroderAbstract:Abstract The two sponge classes, Hexactinellida and Demospongiae, comprise a skeleton that is composed of siliceous skeletal elements (spicules). Spicule growth proceeds by appositional layering of lamellae that consist of silica nanoparticles, which are synthesized via the sponge-specific enzyme silicatein. While in demosponges during maturation the lamellae consolidate to a solid rod, the lamellar organization of hexactinellid spicules largely persists. However, the innermost lamellae, near the spicule core, can also fuse to a solid axial cylinder. Similar to the fusion of siliceous nanoparticles and lamella, in several hexactinellid species individual spicules unify during sintering-like processes. Here, we study the different stages of a process that we termed bio-sintering, within the giant basal spicule (GBS) of Monorhaphis chuni. During this study, a major GBS protein component (27 kDa) was isolated and analyzed by MALDI-TOF-MS. The sequences were used to isolate and clone the encoding cDNA via degenerate primer PCR. Bioinformatic analyses revealed a significant sequence homology to silicatein. In addition, the native GBS protein was able to mediate bio-silica synthesis in vitro. We conclude that the syntheses of bio-silica in M. chuni, and the subsequent fusion of nanoparticles to lamellae, and finally to spicules, are enzymatically-driven by a silicatein-like protein. In addition, evidence is now presented that in hexactinellids those fusions involve sintering-like processes.
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chapter 3 giant siliceous spicules from the deep sea glass sponge monorhaphis chuni
International Review of Cell and Molecular Biology, 2009Co-Authors: Xiaohong Wang, Heinz C Schroder, Werner E G MullerAbstract:Abstract Only 13 years after realizing, during a repair of a telegraph cable pulled out from the deep sea, that the depth of the ocean is plentifully populated with a highly diverse fauna and flora, the Challenger expedition (1873–1876) treasured up a rich collection of vitreous sponges (Hexactinellida). They had been described by Schulze and represent the phylogenetically oldest class of siliceous sponges (phylum Porifera); they are eye‐catching because of their distinct body plan, which relies on a filigree skeleton. It is constructed by an array of morphologically determined elements, the spicules. Soon after, during the German Deep Sea Expedition “Valdivia” (1898–1899), Schulze could describe the largest siliceous hexactinellid sponge on Earth, the up to 3‐m high Monorhaphis chuni , which develops the equally largest bio‐silica structure, the giant basal spicules (3 m × 10 mm). Using these spicules as a model, basic knowledge on the morphology, formation, and development of the skeletal elements could be achieved. They are formed by a proteinaceous scaffold (composed of a 27‐kDa protein), which mediates the formation of the siliceous lamellae, into which the proteins are encased. The high number of 800 of 5–10 μm thick lamellae is concentrically arranged around the axial canal. The silica matrix is composed of almost pure silicon oxide, providing it with unusually optophysical properties, which are superior to those of man‐made waveguides. Experiments might suggest that the spicules function in vivo as a nonocular photoreception system. In addition, the spicules have exceptional mechanical properties, combining mechanical stability with strength and stiffness. Like demosponges, also the hexactinellids synthesize their silica enzymatically, via the enzyme silicatein (27‐kDa protein). It is suggested that these basic insights will surely contribute to a further applied utilization and exploration of silica in bio‐material/biomedical science.
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axial growth of hexactinellid spicules formation of cone like structural units in the giant basal spicules of the hexactinellid monorhaphis
Journal of Structural Biology, 2008Co-Authors: Xiaohong Wang, Alexandra Boreiko, Hermann Gotz, Jaap A. Kaandorp, Heins Duschner, David Brandt, Ute Schlosmacher, Jinhe Li, Heinz C Schroder, Werner E G MullerAbstract:The glass sponge Monorhaphis chuni (Porifera: Hexactinellida) forms the largest bio-silica structures on Earth; their giant basal spicules reach sizes of up to 3 m and diameters of 8.5 mm. Previously, it had been shown that the thickness growth proceeds by appositional layering of individual lamellae; however, the mechanism for the longitudinal growth remained unstudied. Now we show, that the surface of the spicules have towards the tip serrated relief structures that are consistent in size and form with the protrusions on the surface of the spicules. These protrusions fit into the collagen net that surrounds the spicules. The widths of the individual lamellae do not show a pronounced size tendency. The apical elongation of the spicule proceeds by piling up cone-like structural units formed from silica. As a support of the assumption that in the extracellular space silicatein(-like) molecules exist that associate with the external surface of the respective spicule immunogold electron microscopic analyses were performed. With the primmorph system from Suberites domuncula we show that silicatein(-like) molecules assemble as string- and net-like arrangements around the spicules. At their tips the silicatein(-like) molecules are initially stacked and at a later stay also organized into net-like structures. Silicatein(-like) molecules have been extracted from the giant basal spicule of Monorhaphis. Applying the SDS-PAGE technique it could be shown that silicatein molecules associate to dimers and trimers. Higher complexes (filaments) are formed from silicatein(-like) molecules, as can be visualized by electron microscopy (SEM). In the presence of ortho-silicate these filaments become covered with 30-60 nm long small rod-like/cuboid particles of silica. From these data we conclude that the apical elongation of the spicules of Monorhaphis proceeds by piling up cone-like silica structural units, whose synthesis is mediated by silicatein(-like) molecules. (C) 2008 Elsevier Inc. All rights reserved.
Gert Wörheide - One of the best experts on this subject based on the ideXlab platform.
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molecular paleobiology of early branching animals integrating dna and fossils elucidates the evolutionary history of hexactinellid sponges
Paleobiology, 2013Co-Authors: Martin Dohrmann, Dorte Janussen, Sergio Vargas, Allen Gilbert Collins, Gert WörheideAbstract:Reconciliation of paleontological and molecular phylogenetic evidence holds great promise for a better understanding of the temporal succession of cladogenesis and character evolution, especially for taxa with a fragmentary fossil record and uncertain classification. In zoology, studies of this kind have largely been restricted to Bilateria. Hexactinellids (glass sponges) readily lend themselves to test such an approach for early-branching (non-bilaterian) animals: they have a long and rich fossil record, but for certain taxa paleontological evidence is still scarce or ambiguous. Furthermore, there is a lack of consensus for taxonomic interpretations, and discrepancies exist between neontological and paleontological classification systems. Using conservative fossil calibration constraints and the largest molecular phylogenetic data set assembled for this group, we infer divergence times of crown-group Hexactinellida in a Bayesian relaxed molecular clock framework. With some notable exceptions, our results are largely congruent with interpretations of the hexactinellid fossil record, but also indicate long periods of undocumented evolution for several groups. This study illustrates the potential of an integrated molecular/paleobiological approach to reconstructing the evolution of challenging groups of organisms.
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Molecular phylogeny of glass sponges (Porifera, Hexactinellida): increased taxon sampling and inclusion of the mitochondrial protein-coding gene, cytochrome oxidase subunit I
Hydrobiologia, 2012Co-Authors: Martin Dohrmann, Dennis V. Lavrov, Karri M Haen, Gert WörheideAbstract:Marine sponges of the class Hexactinellida (glass sponges) are among the most understudied groups of Porifera, and molecular approaches to investigating their evolution have only recently emerged. Although these first results appeared reliable as they largely corroborated morphology-based hypotheses, they were almost exclusively based on ribosomal RNA genes (rDNA) and should, therefore, be further tested with independent types of genetic data, such as protein-coding genes. To this end, we established the mitochondrial-encoded cytochrome oxidase subunit I gene (COI) as an additional marker, and conducted phylogenetic analyses on DNA- and amino-acid level, as well as a supermatrix analysis based on combined COI DNA and rDNA alignments. Furthermore, we increased taxon sampling compared to previous studies by adding seven additional species. The COI-based phylogenies were largely congruent with the rDNA-based phylogeny but suffered from poor bootstrap support for many nodes. However, addition of the COI sequences to the rDNA data set increased resolution of the overall molecular phylogeny. Thus, although obtaining COI sequences from glass sponges turned out to be quite challenging, this gene appears to be a valuable supplement to rDNA data for molecular evolutionary studies of this group. Some implications of our extended phylogeny for the evolution and systematics of Hexactinellida are discussed.
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deep phylogeny and evolution of sponges phylum porifera
Advances in Marine Biology, 2012Co-Authors: Gert Wörheide, Dirk Erpenbeck, Martin Dohrmann, Oliver Voigt, Claire Larroux, Manuel Maldonado, Carole Borchiellini, Dennis V. LavrovAbstract:Sponges (phylum Porifera) are a diverse taxon of benthic aquatic animals of great ecological, commercial, and biopharmaceutical importance. They are arguably the earliest-branching metazoan taxon, and therefore, they have great significance in the reconstruction of early metazoan evolution. Yet, the phylogeny and systematics of sponges are to some extent still unresolved, and there is an on-going debate about the exact branching pattern of their main clades and their relationships to the other non-bilaterian animals. Here, we review the current state of the deep phylogeny of sponges. Several studies have suggested that sponges are paraphyletic. However, based on recent phylogenomic analyses, we suggest that the phylum Porifera could well be monophyletic, in accordance with cladistic analyses based on morphology. This finding has many implications for the evolutionary interpretation of early animal traits and sponge development. We further review the contribution that mitochondrial genes and genomes have made to sponge phylogenetics and explore the current state of the molecular phylogenies of the four main sponge lineages (Classes), that is, Demospongiae, Hexactinellida, Calcarea, and Homoscleromorpha, in detail. While classical systematic systems are largely congruent with molecular phylogenies in the class Hexactinellida and in certain parts of Demospongiae and Homoscleromorpha, the high degree of incongruence in the class Calcarea still represents a challenge. We highlight future areas of research to fill existing gaps in our knowledge. By reviewing sponge development in an evolutionary and phylogenetic context, we support previous suggestions that sponge larvae share traits and complexity with eumetazoans and that the simple sedentary adult lifestyle of sponges probably reflects some degree of secondary simplification. In summary, while deep sponge phylogenetics has made many advances in the past years, considerable efforts are still required to achieve a comprehensive understanding of the relationships among and within the main sponge lineages to fully appreciate the evolution of this extraordinary metazoan phylum.
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phylogeny and evolution of glass sponges porifera Hexactinellida
Systematic Biology, 2008Co-Authors: Martin Dohrmann, Dorte Janussen, Allen Gilbert Collins, Joachim Reitner, Gert WörheideAbstract:Reconstructing the phylogeny of sponges (Porifera) is one of the remaining challenges to resolve the metazoan Tree of Life and is a prerequisite for understanding early animal evolution. Molecular phylogenetic analyses for two of the three extant classes of the phylum, Demospongiae and Calcarea, are largely incongruent with traditional classifications, most likely because of a paucity of informative morphological characters and high levels of homoplasy. For the third class, Hexactinellida (glass sponges)--predominantly deep-sea inhabitants with unusual morphology and biology--we present the first molecular phylogeny, along with a cladistic analysis of morphological characters. We collected 18S, 28S, and mitochondrial 16S ribosomal DNA sequences of 34 glass sponge species from 27 genera, 9 families, and 3 orders and conducted partitioned Bayesian analyses using RNA secondary structure-specific substitution models (paired-sites models) for stem regions. Bayes factor comparisons of different paired-sites models against each other and conventional (independent-sites) models revealed a significantly better fit of the former but, contrary to previous predictions, the least parameter-rich of the tested paired-sites models provided the best fit to our data. In contrast to Demospongiae and Calcarea, our rDNA phylogeny agrees well with the traditional classification and a previously proposed phylogenetic system, which we ascribe to a more informative morphology in Hexactinellida. We find high support for a close relationship of glass sponges and Demospongiae sensu stricto, though the latter may be paraphyletic with respect to Hexactinellida. Homoscleromorpha appears to be the sister group of Calcarea. Contrary to most previous findings from rDNA, we recover Porifera as monophyletic, although support for this clade is low under paired-sites models.
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two new tretodictyids Hexactinellida hexactinosida tretodictyidae from the coasts of north america
Zootaxa, 2008Co-Authors: Henry M Reiswig, Martin Dohrmann, Shirley A Pomponi, Gert WörheideAbstract:Two new species of the hexactinellid family Tretodictyidae, both collected by submersible, have been discovered off the coasts of North America. The Pacific species, Tretodictyum montereyensis n. sp., has an unusual skeleton with a fused cortex added over the usual tretodictyid system of ridges and grooves on the dermal surface. The Atlantic species, Hexactinella carolinensis n. sp., is unusual among its congeners in having swollen nodes on the dermal skeleton. Diagnoses of both genera have been modified to accommodate the new findings. The fine diactins of both species are found to have shallow brackets and short barbs, confirming their uncinate nature. Addition of these two species raises the number of known North American tretodictyids from one to three.