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Aka microterebrans sp. nov. (A) Ectosomal skeleton; (B) endosomal skeleton A. ruetzleri sp. nov.; (C) dermal membrane made of a layer of irregularly arranged oxeas; (D) irregular reticulum with stouter roundish meshes below the dermal membrane (arrow); (E) very thick spicule tracts showing a parallel course; skeletal organization of Aka maldiviensis; (F) ectosomal skeleton of the fistule; (G) peripheral part of the inner skeleton of the fistule; (H) supporting skeleton of the fistule. Scale bars: D, 200 μm; others, 1 mm.
Source publication
Three new species of the boring genus Aka, A.
coralliirubri, A.
microterebrans and A.
ruetzleri are described respectively from the Mediterranean Sea, Celebes Sea and Caribbean Sea. The Indo-Pacific A.
maldiviensis, known only for the structure of its epilithic fistules, is here described in more detail. The new species confirm that the sponges com...
Contexts in source publication
Context 1
... oxeas tangentially arranged, without forming regular network ( Figure 4A). Endosomal skeleton consisting of interconnected fibres (40-175 μm wide) of numerous, densely packed oxeas, forming elongated meshes (150-800 μm in diameter) ( Figure 4B) filled by numerous scattered oxeas. ...
Context 2
... oxeas tangentially arranged, without forming regular network ( Figure 4A). Endosomal skeleton consisting of interconnected fibres (40-175 μm wide) of numerous, densely packed oxeas, forming elongated meshes (150-800 μm in diameter) ( Figure 4B) filled by numerous scattered oxeas. ...
Context 3
... skeleton of fistules made of layer of loose, irregularly arranged oxeas ( Figure 4C). Under this dermal membrane the oxeas are arranged in paucispicular (3-5) tracts of fibres (50-150 μm wide) forming an irregular reticulum with roundish meshes (100-670 μm) ( Figure 4D). ...
Context 4
... skeleton of fistules made of layer of loose, irregularly arranged oxeas ( Figure 4C). Under this dermal membrane the oxeas are arranged in paucispicular (3-5) tracts of fibres (50-150 μm wide) forming an irregular reticulum with roundish meshes (100-670 μm) ( Figure 4D). This network increasingly stouter towards fistular lumen. ...
Context 5
... network increasingly stouter towards fistular lumen. In this zone tracts of 100-650 μm thickness and meshes 400- 1000 μm wide ( Figure 4E). In the basal part of fistules, inside the lower part of coral, very thick spicule tracts showing parallel course were observed ( Figure 4E). ...
Context 6
... this zone tracts of 100-650 μm thickness and meshes 400- 1000 μm wide ( Figure 4E). In the basal part of fistules, inside the lower part of coral, very thick spicule tracts showing parallel course were observed ( Figure 4E). Endosomal spicules irregularly arranged. ...
Context 7
... walls with a thin ectosomal skeleton formed by tangential, almost regular, reticulate meshes incorporating coral sand grains ( Figure 4F). Ectosome supported by fan- shaped, paucispicular (3-4) tracts of oxeas corresponding to peripheral part of inner skeleton ( Figure 4G). ...
Context 8
... walls with a thin ectosomal skeleton formed by tangential, almost regular, reticulate meshes incorporating coral sand grains ( Figure 4F). Ectosome supported by fan- shaped, paucispicular (3-4) tracts of oxeas corresponding to peripheral part of inner skeleton ( Figure 4G). Supporting skeleton of fistules consisting of long, stout, multispicular tracts of spicules (75-370 μm thick) forming irregular reticulum with circular or elongated meshes (113-603 μm wide) ( Figure 4H). ...
Context 9
... supported by fan- shaped, paucispicular (3-4) tracts of oxeas corresponding to peripheral part of inner skeleton ( Figure 4G). Supporting skeleton of fistules consisting of long, stout, multispicular tracts of spicules (75-370 μm thick) forming irregular reticulum with circular or elongated meshes (113-603 μm wide) ( Figure 4H). The skeleton inside the boring chambers is formed by disorderly and densely arranged spicules. ...
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... Porifera research has been carried out in the Indonesia region since the late 19 th century (Breitfuss 1898;Hardwicke 1822;Herklots & Marshall 1868;Kieschnick 1896;Marshall 1875;Poléjaeff 1883;Quoy & Gaimard 1833;Ridley 1884bRidley , 1885Schulze 1887;Sollas 1888;Thiele 1899;Topsent 1897) and early to mid-20 th century (Annandale 1924;Brøndsted 1934;Burton 1930b;Dendy 1913;Hentschel 1912;Ijima 1927;Lévi 1964;Reid 1968;Thiele 1900Thiele , 1903Vosmaer 1911) including surrounding regions (Lévi 1961;Wilson 1925). In addition, several modern ecological studies have been conducted on Indonesian sponge communities (Amir 1992;Bell & Smith 2004;Rovellini et al. 2019;van Soest 1989van Soest , 1990de Voogd et al. 1999de Voogd et al. , 2004, including taxonomic studies with novel species descriptions (Alvarez et al. 2016;Azzini et al. 2007;Becking 2013;Calcinai et al. 2006Calcinai et al. , 2007Calcinai et al. , 2013Calcinai et al. , 2017aLim & Setiawan 2021;Marlow et al. 2021;Muricy 2011;van Soest et al. 2021;van Soest & de Voogd 2015;de Voogd 2003de Voogd , 2004de Voogd & van Soest 2002, 2007de Weerdt & van Soest 2001). These studies give significant information on sponge diversity and distribution throughout the Indonesian archipelago. ...
... Siphonodictyon microterebrans (Calcinai, Cerrano & Bavestrello, 2007) 10 Sulawesi Sea/Makassar Strait 192 Megaciella tawiensis (Wilson, 1925) 146 Palawan/North Borneo (Wilson 1925) 204 ...
Sponges in Indonesia have been studied since the 19th century during several historical expeditions and international collaborations. Hundreds of new species were reported from various locations, e.g., Ambon, Ternate, Sulawesi, Aru, and Kei Islands. This study aimed to create a sponge (Porifera: Calcarea, Demospongiae, Hexactinellida, and Homoscleromorpha) species checklist from Indonesia based on World Porifera Database. With a total of 731 species, our checklist comprises approximately 45 species of Calcarea, 566 species of Demospongiae, 115 species of Hexactinellida, and five species of Homoscleromorpha. The number of species are recorded from 12 marine ecoregions across the Indonesian Archipelago and freshwater habitats (Spongillida) between 1820–2021. The species composition indicates higher regional endemism or poorly studied since no other report after the original description. However, several marine ecoregions of Indonesia remain highly overlooked (e.g., Northeast Sulawesi, Papua, Southern Java, Western Sumatra), including freshwater habitats. Therefore, a taxonomic biodiversity baseline study, particularly on Porifera, is necessary to better understand the aquatic and marine biodiversity in the Indonesia Archipelago.
... According to the findings of Calcinai et al. (2003Calcinai et al. ( , 2004, it is possible to attribute the boring agent of the Sciacca red coral to a species of the genus Siphonodictyon based on the micro-layered concentric pattern reaching the centre of the pits. In the Mediterranean Sea, two species of Siphonodictyon, Siphonodictyon insidiosa (Johnson, 1899) and Siphonodictyon coralliirubri Calcinai, Cerrano and Bavestrello, 2007, are recognized (Calcinai et al. 2007). The average size of the pits suggests that, very likely, S. coralliirubri is responsible for the bioerosion recorded in the Sciacca red coral. ...
... According to the findings of Calcinai et al. (2003Calcinai et al. ( , 2004, it is possible to attribute the boring agent of the Sciacca red coral to a species of the genus Siphonodictyon based on the micro-layered concentric pattern reaching the centre of the pits. In the Mediterranean Sea, two species of Siphonodictyon, Siphonodictyon insidiosa (Johnson, 1899) and Siphonodictyon coralliirubri Calcinai, Cerrano and Bavestrello, 2007, are recognized (Calcinai et al. 2007). The average size of the pits suggests that, very likely, S. coralliirubri is responsible for the bioerosion recorded in the Sciacca red coral. ...
The sub-fossil red coral deposits of Sciacca (Sicily Channel) have attracted scientific attention for nearly 150 years. Their origin and formation have been long questioned and investigated, given the fact that they represent one of the most intriguing geobiological events ever to occur in the Mediterranean basin. Less attention was given to the paleo-community associated with the sub-fossil coral. Radiocarbon age determinations, in particular, were provided only for red coral, neglecting the possibility of understanding which species were simultaneously present in the coralline paleo-community and which was their role. The study of cemented coral rubble pieces revealed that Corallium rubrum covered the largest time interval (more than 3000 years) and was contemporary to many secondary epibionts over two millennia and to Madrepora oculata for about 500 years; this last finding suggested that an uncommon co-dominance between the two structuring species occurred in the nearby living communities. The lack of Fe–Mg deposits on the cemented coral rubbles coupled with the low bioerosion rate of the red coral skeletons by the demosponge Siphonodictyon coralliirubri (assessed through the analysis of the erosive paleo-scars) suggested that the deposits met with a rapid sediment cover-up. Moreover, for the first time, the analysis of a piece of cemented coral rubble of sub-fossil red coral coming from Sardinian waters confirmed that, albeit to a lesser extent, the conditions favouring the preservation of dead corals can occur also in different localities far from Sciacca.
... Unfortunately, it was not possible to remove fragments of etched material for an accurate microscopical analysis. Nevertheless, the large excavations extending to the entire scleraxis leaving free only a thin sheet of carbonate are very similar to those recorded in dead red coral from the Alboran Sea and attributed to Delectona ciconiae Bavestrello, Calcinai and Sarà, 1996 [47], while the spongiosus micro-excavation are very similar to those of Siphonodictyon corallirubri (Calcinai, Cerrano and Bavestrello, 2007) [48]. ...
... Unfortunately, it was not possible to remove fragments of etched material for an accurate microscopical analysis. Nevertheless, the large excavations extending to the entire scleraxis leaving free only a thin sheet of carbonate are very similar to those recorded in dead red coral from the Alboran Sea and attributed to Delectona ciconiae Bavestrello, Calcinai and Sarà, 1996 [47], while the spongiosus micro-excavation are very similar to those of Siphonodictyon corallirubri (Calcinai, Cerrano and Bavestrello, 2007) [48]. ...
The precious red coral (Corallium rubrum L.) represents one of the most fascinating marine species of the Mediterranean Sea. Several samples, including red coral together with its accompanying species, were found in the zoological collection of the Italian pioneer biologist Lazzaro Spallanzani (1729–1799), collected in the Messina Strait during his voyage in Sicily (1788). The study of these samples allowed the inclusion of numerous additional species in the traditional red coral facies as the large oyster Neopycnodonte cochlear, the giant barnacle Pachylasma giganteum, the mesophotic scleractinian Caryophyllia (Caryophyllia) cyathus. These specimens proved to be very useful in describing the diversity of the paleo-community including red coral, shedding light on its formation processes. In particular, some specimens are composed of red coral rubble consolidated and cemented with other carbonatic remains Probably, these peculiar specimens have a similar origin to those of the Sciacca Banks already known from the Sicily Channel. In fact, the two areas are prone to intense seismic activity that periodically causes mass mortalities of red coral from nearby rocky reliefs and the formation of biogenic detritus, while the resulting chemical environment of the water and the sediments allows the consolidation of the carbonatic remains.
... Most of Porifera, being modular organisms, typically produce numerous serial erosion chambers ( Figure 5D) connected to each other, creating a macro pattern of bioerosion, and to the surface of the substrate through the papillae. These features can be useful diagnostic elements since many species are characterized by cavities with a peculiar shape and/or size (Bromley, 1978;Calcinai et al., 2007). In fact, many erosion traces are attributed to different ichnospecies belonging to the ichnogenus Entobia (biogenus Cliona) ( Figure 6B) considering the morphological characteristics of the cavity networks (Bromley and D'Alessandro, 1984). ...
Bioerosion is the destruction of hard substrates resulting from biological activity, and plays a relevant role in the ecological interactions and coastal dynamics processes. Several organisms have evolved structures and behaviors allowing them to perforate biotic and abiotic surfaces, transforming hard surfaces into particles, and contributing significantly to sediment production in the coastal and marine environment. Due to the large geographical diffusion of marine borers, bioerosion is relevant in many scientific and applied fields of interest. Most bioerosion studies have hitherto been conducted in tropical areas, where borers are a critical component of coral reef destruction. Comparatively, little information is available for the bioerosion of submerged archeological heritage. This review focuses on the bioerosion of archeological calcareous artifacts in the Mediterranean Sea, summarizing studies concerning the colonization of statues, shipwrecks, cargo, and the remains of submerged cities. The paper includes the first comprehensive listing of the archeological sites in the Mediterranean Sea where bioerosion has been assessed. The diversity of boring organisms affecting marine archeological remains and their boring patterns, the various types of bored materials, and the severity of the damage caused to heritage artifacts are also included. Both microborers (algae, fungi, and cyanobacteria) and macroborers (sponges, bivalves, polychaetes, sipunculids, and echinoids) are considered, and their roles in the structuring of endolithic assemblages are also covered. The experimental techniques currently employed to analyze bioerosion traces, helping to identify particular species and ichnospecies and their ecological dynamics, are also considered. Finally, a discussion of the current strategies proposed for the in situ protection and conservation of Underwater Cultural Heritage is provided.
... The resulting substrate chip is mechanically dislodged and discarded via cell transport and water currents (Warburton 1958;Rützler and Rieger 1973). Sponge chip diameters commonly range from 15 to 100 μm, but were most frequently assessed as being between 30 and 60 μm in diameter (Rützler and Rieger 1973;Fütterer 1974;Rützler 1975;Schönberg 2000;Calcinai et al. 2002Calcinai et al. , 2007. They are therefore predominantly part of the silt fraction of the sediment and are most abundant in the coarse silt fraction (Table 1; e.g. ...
Bioeroding sponges are important macroborers that chemically cut out substrate particles (chips) and mechanically remove them, thereby contributing to reef-associated sediment. These chemical and mechanical proportions vary with elevated levels of partial pressure of carbon dioxide (pCO2). To assess related impacts, the morphometric parameters “chip diameter” and “etching fissure width” were analyzed for Cliona orientalis Thiele, 1900, hypothesizing that their dimensions would differ with different pCO2 exposures (72 h at ca. 400, 750 and 1700 μatm). Under ambient conditions, we obtained a mean chip diameter of 21.6 ± 0.7 μm and a mean fissure width of 0.29 ± 0.01 μm. Chips were evenly distributed across the medium and coarse silt fractions regardless of treatment. We could not find a reliable pCO2 treatment effect for chip diameter and fissure width, but we observed strong data variability not related to our key questions. A hierarchical data design further reduced the test power. Fissure width was the more sensitive, but also more variable parameter. Sample size analyses nevertheless indicated that we had processed enough data. Thus, we reject our scenario of an increase in fissure width and consequent reduction in chip size to explain why chemical sponge bioerosion increases more strongly than the mechanical counterpart. Instead, we propose that a lowered ambient pH may favor respiratory acid build-up in the sponge tissue, possibly leading to a less localized bioerosion, causing bias towards more chemical bioerosion. Overall, this does not seem to affect the morphometry of sponge chips and the quality of sponge-generated sediment.
... Alboran Sea, 100-200 m, from Corallium rubrum community, but maybe not in the coral), Maldonado(1992, as Cliona, Alboran Sea, 70-120 m, in Corallium rubrum),Cruz-Simó (2002, as Cliona, Canary Islands, depth not stated, in Dendrophyllia ramea),Hansson (1999, Scandinavia, depth and substrate not specified) Siphonodictyon corallirubri(Calcinai et al., 2007b) Tyrrhenian Sea, depth unknown, in Corallium rubrum AM:Calcinai et al. (2010, Mediterranean, depth not stated, in precious coral) Madeira, depth not stated, in bivalve shells AM:? Topsent (1904, as Cliona labyrinthica),? Alander (1942, as Aka labyrinthica, W Norway and Sweden, 85-300 m, in Lophelia),Melone (1965, as Cliona labyrinthica, 60-75 m, Strait of Bonifacio in Corallium rubrum), ? ...
Bioeroding sponges play a central role in carbonate cycling on corals reefs. They may respond differently to habitat deterioration than many other benthic invertebrates, because at some locations, their abundances increased after disturbance. We reviewed literature on these sponges in context of environmental change and provide meta-analyses at global level. A difficult taxonomy and scarce scientific expertise leave them inadequately studied, even though they are the best-known internal bioeroders. They are sheltered within the substrate they erode, appear to be comparatively resilient against environmental change and can have heat-resistant photosymbionts and ‘weedy’ traits, including multiple pathways to reproduce or disperse and fast growth and healing abilities. Especially temperature stress appears to disable calcifiers stronger than bioeroding sponges. Moreover, increases in bioeroding sponge abundances have been related to eutrophication and disturbances that led to coral mortality. Chemical sponge bioerosion is forecast to double with doubled partial pressure of carbon dioxide, but reduced substrate density may counteract this effect, as dominant sponges erode more in denser substrates. Case examples portray shifting impacts of bioeroding sponges with environmental change, with some reefs already being erosional. Most available data and the largest known species record are from the Caribbean. Data from the Coral Triangle and India are largely restricted to faunistic records. Red Sea, Japanese and cold-water reef bioeroding sponges are the least studied. We need more quality research on functions and interaction effects, about which we are still insufficiently informed. With many calcifiers increasingly failing and bioeroding sponges still doing well, at least at intermediate levels of local and global change, these sponges may continue to significantly affect coral reef carbonate budgets. This may transform them from valuable and necessary recyclers of calcium carbonate to problem organisms.
... n. are, on average, considerably larger than in E. cretacea could be explained by fusion of several smaller chambers. On the other hand, even though there are at least some cases where extant species of Siphonodictyon develop from one growth type into another (Calcinai et al., 2007), such fusion of chambers would be quite unusual for Siphonodictyon (C. H. L. Schönberg, personal communication, 2017). ...
The ongoing technical revolution in non-destructive 3-D visualisation via micro-computed tomography (micro-CT) finds a valuable application in the studies of bioerosion trace fossils, since their three-dimensional architecture is hidden within hard substrates. This technique, in concert with advanced segmentation algorithms, allows a detailed visualisation and targeted morphometric analyses even of those bioerosion traces that are otherwise inaccessible to the widely applied cast-embedding technique, because they either are filled with lithified sediment or cement or are preserved in inherently insoluble or silicified host substrates, or because they are established type material and should not be altered.
In the present contribution selected examples of such cases are illustrated by reference to bioerosion trace fossils preserved in Late Cretaceous belemnite guards from the European Chalk Province. These case studies comprise an analysis of a diverse ichno-assemblage found associated with the lectotype of the microboring Dendrina dendrina (Morris, 1851) in a belemnite from the upper Campanian to lower Maastrichtian chalk of Norfolk, England, and the description of two new bioerosion trace fossils with type specimens found in belemnite guards from the lower Campanian limestones of Höver, Germany. The latter are Lapispecus hastatus isp. n., a tubular and occasionally branched macroboring for which a sipunculan or a phoronid trace maker are discussed, and Entobia colaria isp. n., a camerate network formed by an excavating sponge that eroded diagnostic grated apertures at the locations of the presumed inhalant papillae or exhaling pores, adding to or replacing filtering devices that are otherwise made of tissue and spicules.
As an added value to the non-destructive visualisation procedure, the processed X-ray micro-CT scans of the studied type material provide 3-D models that may now serve as digitypes that can be studied as digital facsimile without the necessity of consulting the actual type specimens.
... 6B, 6C, 8). The mm-scale chambers are characteristic of the central excavation structures produced by sponges of the genus Aka (Calcinai et al. 2007). These chambers are 0.5–5 mm-long, are preferentially located in the middle nacreous layer, and protrude with canals or tunnels into the internal and external prismatic layers (Fig. 8A– 8D). ...
The dependence of skeletal alteration on time spent in the taphonomic active zone (TAZ) can generate a taphonomic clock, which can be used to quantify scales of time averaging and rates of skeletal production and recycling in the fossil record. However, the strength of the taphonomic clock is variable in present-day shallow marine environments and it is unclear how this strength varies with depth. Here, we assess the strength of the taphonomic clock in Nautilus macromphalus dead shells that were collected in cool-water, sediment-starved, epi- and mesobathyal environments off New Caledonia and range in postmortem age from few decades to several millennia. We find that, first, differences in the onset and extent of alteration states in the epibathyal zone (< 750 m) segregate well-preserved shells with red stripes (less than ∼ 200 years) from encrusted shells with faded colors and extensively bored by sponges (∼ 400 years), and from strongly fragmented, bored, and coated shell relicts (> 1,000 years). The onset of dissolution and formation of clay-goethitic coating occurs earlier (∼ 200 years) in the mesobathyal zone (> 750 m) than in the epibathyal zone. Clay-goethitic rims and boring infills show signs of microbial binding, pelletization, and coccolith dissolution and can represent nascent stages of glauconitization. Second, shells several centuries old show differences between right and left flanks (1) in the degree of encrustation and sponge bioerosion in the epibathyal zone and (2) in the extent of clay-goethitic coating in the mesobathyal zone. The upper flanks are ultimately removed in both depth zones, leaving relict half-shells that are millennia old. Third, the depth dependence of alteration can reflect a bathymetric decline in disintegration rates by heterotrophic borers due to a reduced productivity in the mesobathyal zone and an increase in dissolution rates due to the proximity of the aragonite compensation depth. The between-flank asymmetry in preservation implies (1) horizontal position of shells close to the sediment-water interface for several decades or centuries without being overturned or subjected to reworking and (2) shell exposure to two distinct taphonomic regimes separated by few centimeters, with the upper flank located in the TAZ and the lower flank facing a less aggressive sediment zone. The stable exposure of shells in the taphonomic active zone and slow alteration rates in bathyal environments allow discriminating between within-habitat time-averaged assemblages on one hand and environmentally or stratigraphically condensed assemblages on the other hand.
... Siphonodictyon ruetzleri (Calcinai, Cerrano & Bavestrello, 2007) Synonymy and references. Aka ruetzleri Calcinai, Cerrano & Bavestrello, 2007: 1362 Xestospongia purpurea new species (Figures 4f, 41) Material. ...
... Siphonodictyon ruetzleri (Calcinai, Cerrano & Bavestrello, 2007) Synonymy and references. Aka ruetzleri Calcinai, Cerrano & Bavestrello, 2007: 1362 Xestospongia purpurea new species (Figures 4f, 41) Material. Holotype: USNM 1229140, Carrie Bow forereef cave, 18 m. ...
The Caribbean barrier reef near Carrie Bow Cay, Belize, has been a focus of Smithsonian Institution (Washington) reef and mangrove investigations since the early 1970s. Systematics and biology of sponges (Porifera) were addressed by several researchers but none of the studies dealt with cryptic habitats, such as the shaded undersides of coral rubble, reef crevices, and caves, although a high species diversity was recognized and samples were taken for future reference and study. This paper is the result of processing samples taken between 1972 and 2012. In all, 122 species were identified, 14 of them new (including one new genus). The new species are Tetralophophora (new genus) mesoamericana, Geodia cribrata, Placospongia caribica, Prosuberites carriebowensis, Timea diplasterina, Timea oxyasterina, Rhaphidhistia belizensis, Wigginsia curlewensis, Phorbas aurantiacus, Myrmekioderma laminatum, Niphates arenata, Siphonodictyon occultum, Xestospongia purpurea, and Aplysina sciophila. We determined that about 75 of the 122 cryptic sponge species studied (61%) are exclusive members of the sciophilic community, 47 (39 %) occur in both, light-exposed and shaded or dark habitats. Since we estimate the previously known sponge population of Carrie Bow reefs and mangroves at about 200 species, the cryptic fauna makes up 38 % of total diversity.
... According to the latest available revision of coralligenous biodiversity (Ballesteros 2006), 142 species of sponges have been recorded associated with this community. Adding to this list the species recorded on the coralligenous of Apulia (Sarà 1968 Calcinai et al. 2007b) and the data of the present study, the total number of sponge species hitherto associated to the coralligenous community increases to 273 ( Table 2). ...
... As to the boring sponges, Cliona janitrix is indicated by Ballesteros (2006) and Calcinai et al. (2007b) as the key species in the bio-erosive processes involving Corallium rubrum, whereas Cliona viridis has the same role in the coralligenous matrix (Rosell et al. 1999). According to our data Cliona celata Grant, 1826, C. schmidtii (Ridley, 1881), Spiroxya corallophila (Calcinai, Cerrano & Bavestrello, 2002), S. heteroclita Topsent, 1896 and Siphonodictyon insidiosum (Johnson, 1899) may also be considered important in the bio erosive processes acting upon the coralligenous structure. ...
... 3 B)and Pachastrella monilifera Schmidt, 1868(Fig. 3 C)were generally recorded as massive but also described as insinuating by Pulitzer-Finali (1970, 1983)andCalcinai et al. (2007b). ...
Temperate reefs, built by multilayers of encrusting algae accumulated during hundreds to thousands of years, represent one of the most important habitats of the Mediterranean Sea. These bioconstructions are known as “coralligenous” and their spatial complexity allows the formation of heterogeneous microhabitats offering opportunities for a large number of small cryptic species hardly ever considered.
Although sponges are the dominant animal taxon in the coralligenous rims with both insinuating and perforating species, this group is until now poorly known. Aim of this work is to develop a reference baseline about the taxonomic knowledge of sponges and, considering their high level of phenotypic plasticity, evaluate the importance of coralligenous accretions as a pocket for biodiversity conservation.
Collecting samples in four sites along the coast of the Ligurian Sea, we recorded 133 sponge taxa (115 of them identified at species level and 18 at genus level). One species, Eurypon gracilis is new for science; three species, Paratimea oxeata, Clathria (Microciona) haplotoxa and Eurypon denisae are new records for the Italian sponge fauna, eleven species are new findings for the Ligurian Sea. Moreover, seventeen species have not been recorded before from the coralligenous community. The obtained data, together with an extensive review of the existing literature, increase to 273 the number of sponge species associated with the coralligenous concretions and confirm that this habitat is an extraordinary reservoir of biodiversity still largely unexplored, not only taxonomically, but also as to peculiar adaptations and life histories.
