Staying well connected - Lithistid sponges on seamounts

Three species of lithistid sponges, Neoaulaxinia zingiberadix, Isabella mirabilis and Neoschrammeniella fulvodesmus were collected from deep seamounts off New Caledonia to address questions about their population structure, gene flow and the relative contribution of sexual and asexual reproductive strategies to their populations. The sponges were tested by sequencing the ITS (internal transcribed spacer) and CO1 regions of their genomes. These rare and presumably ancient sponges have a distribution restricted to seamounts in the south-western Pacific. Deep seamounts represent geographically separated islands. Although the sponges could be expected to have sexual reproduction restricted to near neighbours due to low sexual dispersal opportunities via larvae, this study found surprisingly high levels of gene flow between the seamounts. Amongst the specimens of N. zingiberadix taken from two seamounts there was no population structure;CO1 resulted in identical genotypes. For the population structure within N. fulvodesmus, as revealed by ITS, most of the variation was within each individual from the six seamounts on which it occurred and CO1 revealed no difference between individuals or seamounts. The third species I. mirabilis showed four genotypes based on CO1, which were distributed across all the seamounts. Indirect measures of different species showed a range of reproductive strategies from asexual to sexual, but with much higher connection between seamounts than previously thought. Individual seamounts did not show a separate population structure as one might expect from 'islands'. The conclusion must be that these sponges have mechanisms to attain greater dispersal than previously thought

Patterns of sponge biodiversity in the Pilbara, Northwestern Australia

This study assessed the biodiversity of sponges within the Integrated Marine and Coastal Regionalisation for Australia (IMCRA) bioregions of the Pilbara using datasets amalgamated from the Western Australian Museum and the Atlas of Living Australia. The Pilbara accounts for a total of 1164 Linnean and morphospecies. A high level of “apparent endemism” was recorded with 78% of species found in only one of six bioregions, with less than 10% confirmed as widely distributed. The Ningaloo, Pilbara Nearshore and Pilbara Offshore bioregions are biodiversity hotspots (>250 species) and are recognised as having the highest conservation value, followed by North West Shelf containing 232 species. Species compositions differed between bioregions, with those that are less spatially separated sharing more species. Notably, the North West Province bioregion (110 species) exhibited the most distinct species composition, highlighting it as a unique habitat within the Pilbara. While sponge biodiversity is apparently high, incomplete sampling effort for the region was identified, with only two sampling events recorded for the Central West Transition bioregion. Furthermore, only 15% of records in the dataset are presently described (Linnean) species, highlighting the continuing need for taxonomic expertise for the conservation and management of marine biodiversity resource

Substratum selection in coral reef sponges and their interactions with other benthic organisms

Substratum preferences and contact interactions among sessile organisms can be a major determinant of biotic gradients in the structure of benthic communities on coral reefs. Sponges are a substantial component of these communities, but their substratum requirements and interactions with other benthic taxa are poorly understood. Here, we quantified sponge substratum preferences and interactions from 838 randomly selected photo-quadrats across different depths (5, 10 and 15 m), exposure (sheltered and exposed), and substratum topography (horizontal, inclined and vertical surfaces) on coastal coral reefs in Kimbe Bay. A high proportion (55%) of sponge colonies were associated with dead coral, unconsolidated coral rubble (7%) and calcium carbonate rock (CaCO3 rock) (7%), even though they represented only 10%, 4% and 1% of the available substratum, respectively. Sponges interacted most frequently with algae (~ 34%), corals (~ 30%) and crustose coralline algae (CCA ~ 19%) that represented ~ 46%, ~ 18% and ~ 14% of the substratum cover, respectively. The microhabitat preferences of sponges and frequency of interactions with other taxa were mostly consistent across various exposure, depth and substratum topography conditions. Most interactions appeared to be “stand-offs” (71%) which are interactions with no clear winner or loser. However, when overgrowth occurred, sponges were usually winners, overgrowing corals (92%), CCA (81%) and macroalgae (65%). Three sponge species Dysidea sp1, Lamellodysidea cf. chlorea and Lamellodysidea chlorea accounted for 51% to 96% of the overgrowth of sponges over algae, corals and CCA, but there was no one species found to always win or lose. Our results suggest that sponges avoid other biological substrata by preferentially settling on dead coral, coral rubble and CaCO3 rock, but when they do come into contact with algae and corals, they frequently overgrow their spacial competitors

An Australian origin for the candle nut (Aleurites, Crotonoideae, Euphorbiaceae) and the fossil record of the Euphorbiaceae and related families in Australia and New Zealand

A fossil seed from south east Queensland referable to the extant genus Aleurites (candlenut) is described as a new species, A. australis, and is one of the few macrofossil records of Euphorbiaceae from Australia. The new fossil data and phylogenetic studies of the biogeographical relationships of Aleurites based upon analysis of rbcL and trnL-F sequence data support a Gondwanic origin for the clade. The macrofossil record of Euphorbiaceae in Australia is restricted to seeds of Aleurites; and fruits of Fontainocarpa which are thought to have affinities with Fontainea, and both extant genera are referable to the Crotonoideae. One group of crotonoids has inaperturate spheroidal pollen, that is comparable to the dispersed pollen genus, Crotonipollis, which has an Oligocene to Recent range in Australia. The fossil pollen record in Australia and New Zealand of other Euphorbiaceae and related families includes species of Malvacipollis that have affinities to the Picrodendraceae; Nyssapollenites endobalteus (McIntyre) Kemp and Harris has affinities with the subfamily Acalyphoideae (Euphorbiaceae); and putative records of Homalanthus suggest affinities with the subfamily Euphorbioideae (Euphorbiaceae). Fossil fruits of Glochidion provide possible evidence of the Phyllanthaceae. The stratigraphic range of these taxa in respect to the Weddellian Biostratigraphic Province, which includes southern South America, western Antarctica, New Zealand, and eastern Australia is also briefly reviewed

An elongated COI fragment to discriminate botryllid species and as an improved ascidian DNA barcode

Botryllids are colonial ascidians widely studied for their potential invasiveness and as model organisms, however the morphological description and discrimination of these species is very problematic, leading to frequent specimen misidentifications. To facilitate species discrimination and detection of cryptic/new species, we developed new barcoding primers for the amplification of a COI fragment of about 860 bp (860-COI), which is an extension of the common Folmer's barcode region. Our 860-COI was successfully amplified in 177 worldwide-sampled botryllid colonies. Combined with morphological analyses, 860-COI allowed not only discriminating known species, but also identifying undescribed and cryptic species, resurrecting old species currently in synonymy, and proposing the assignment of clade D of the model organism Botryllus schlosseri to Botryllus renierii. Importantly, within clade A of B. schlosseri, 860-COI recognized at least two candidate species against only one recognized by the Folmer's fragment, underlining the need of further genetic investigations on this clade. This result also suggests that the 860-COI could have a greater ability to diagnose cryptic/new species than the Folmer's fragment at very short evolutionary distances, such as those observed within clade A. Finally, our new primers simplify the amplification of 860-COI even in non-botryllid ascidians, suggesting their wider usefulness in ascidians

Soft sponges with tricky tree: On the phylogeny of dictyoceratid sponges

Keratose (horny) sponges constitute a very difficult group of Porifera in terms of taxonomy due to their paucity of diagnostic morphological features. (Most) keratose sponges possess no mineral skeletal elements, but an arrangement of organic (spongin) fibers, with little taxonomic or phylogenetic information. Molecular phylogenetics have targeted this evolutionary and biochemically important lineage numerous times, but the conservative nature of popular markers combined with ambiguous identification of the sponge material has so far prevented any robust phylogeny. In the following study, we provide a phylogenetic hypothesis of the keratose order Dictyoceratida based on nuclear markers of higher resolution potential (ITS and 28S C‐region), and particularly aim for the inclusion of type specimens as reference material. Our results are compared with previously published data of CO1, 18S, and 28S (D3‐D5) data, and indicate the paraphyly of the largest dictyoceratid family, the Thorectidae, due to a sister group relationship of its subfamily Phyllospongiinae with Family Spongiidae. Irciniidae can be recovered as monophyletic. Results on genus level and implications on phylogenetic signals of the most frequently described morphological characters are discussed

α-Synuclein aggregation inhibitory activity of the bromotyrosine derivatives aerothionin and aerophobin-2 from the subtropical marine sponge Aplysinella sp

The neuronal protein α-synuclein (α-syn) is one of the main constituents of intracellular amyloid aggregations found in the post-mortem brains of Parkinson’s disease (PD) patients. Recently, we screened the MEOH extracts obtained from 300 sub-tropical marine invertebrates for α-syn binding activity using affinity MS and this resulted in the extract of the Verongida marine sponge Aplysinella sp. 1194, (QM G339263) displaying molecules that bind to the protein. The subsequent bioassay-guided separation of the Aplysinella sp. extract led to the isolation of the known bromotyrosine derivatives (+)-aerothionin (1) and (+)-aerophobin-2 (2). Both compounds bind to α-syn as detected by a MS affinity assay and inhibit α-syn aggregation in an assay that uses the fluorescence probe, thioflavin T, to detect aggregation. (+)-Aerothionin (1) was toxic to primary dopaminergic neurons at its expected α-syn aggregation inhibitory concentration and so could not be tested for pSyn aggregates in this functional assay. (+)-Aerophobin-2 (2) was not toxic and shown to weakly inhibit pSyn aggregation in primary dopaminergic neurons at 10 µM.Peer reviewe

Hesperine, a new imidazole alkaloid and α-synuclein binding activity of 1-methyl-1,2,7,8-tetrahydro-2,8-dioxoadenosine from the marine sponge Clathria (Thalysias) cf. hesperia

During a high-throughput screen of 300 Australian marine invertebrate extracts, the extract of the marine sponge Clathria (Thalysias) cf. hesperia was identified with α-synuclein binding activity. The bioassay-guided purification of this extract resulted in the isolation of 1-methyl-1,2,7,8-tetrahydro-2,8-dioxoadenosine (2) as the α-syn binder along with one new compound, hesperine (1), and five known compounds, indole-3-carboxaldehyde (3), (Z)-2'-demethylaplysinopsin (4), 2-amino-4'-hydroxyacetophenone (5), 4-hydroxybenzoic acid (6) and 4-hydroxybenzaldehyde (7). Herein, we report the structure elucidation of hesperine (1) and α-syn binding activity of 1-methyl-1,2,7,8-tetrahydro-2,8-dioxoadenosine (2).Peer reviewe

Evolution and phylogeny of glass-sponge-associated zoantharians, with a description of two new genera and three new species

Hexactinellid sponges are important members of deep-sea benthic ecosystems because they provide available hard substrate habitats for filter-feeding invertebrates. However, symbioses between hexactinellid sponges and their symbionts are poorly known. Zoantharians associated with hexactinellid sponges have been reported widely from deep-sea marine ecosystems, either on the bodies or stalks of hexactinellid sponges. Despite these records, there has been a lack of research on their diversity and phylogenetic relationships. In this study, 20 specimens associated with amphidiscophoran and hexasterophoran sponges were collected from the waters of Australia and Japan in the Pacific, and from Curaçao in the southern Caribbean, and these were examined in addition to museum specimens. Based on molecular phylogenetic analyses and morphological observations, we formally describe two new genera and three new species of Zoantharia and report several previously described species. The results suggest at least two independent origins for the symbioses between hexactinellid sponges and zoantharians. Our results demonstrate that the diversity of hexactinellid sponge-associated zoantharians is much higher than has been previously thought. The new taxa described in this work further reconfirm that the deep-sea harbours high levels of undescribed zoantharian diversity.journal articl