Freshwater Sponges from the Deccan Traps of India.

Freshwater Sponges of the Order Spongillida have a long fossil record, with isolated spicules known from the Permo-Carboniferous of the Massif Central of France and the Saar-Nahe Basin of southwest Germany, and the oldest identifiable species, Spongilla purbeckensis, coming from the Jurassic of England. Despite this, fossils of Freshwater Sponges are extremely rare, due to the fragile nature of their siliceous skeletons. Most fossils assignable to the Spongillida are simple spicules, which cannot be placed within a family, genus, or species, with more detailed classification requiring the discovery of gemmuloscleres, spicules which produce gemmules, an asexual reproductive stage. The oldest known fossil gemmule attributable to the Spongillida is Palaeospongilla chubutensis from the Lower Cretaceous of Patagonia.

Spicules of Freshwater Sponges have been recorded from several sites within the Cretaceous-Palaeocene Deccan Traps deposits of India, although most of these have been impossible to identify, although in 2021 a new species of Freshwater Sponge, Palaeocorvospongilla cretacea, was described from the Terminal Cretaceous Deccan intertrappean lacustrine deposits of the Malwa Group of Madhya Pradesh.

In a paper published in the journal Acta Palaeontologica Polonica on 8 March 2023, Bandana Samant of the Department of Geology at Rashtrasant Tukadoji Maharaj Nagpur University, Roberto Pronzato of the Dipartimento di Scienze della Terra, dell’Ambiente e della Vita at the Università di Genova, Dhananjay Mahendrakumar Mohabey of the Geological Survey of India, Tiziana Cubeddu and Giacinta Angela Stocchino of the Dipartimento di Medicina Veterinaria at the Università di Sassari, Krutika Jangale, Pranay Thalal, and Anup Dhobale, also of the Department of Geology at Rashtrasant Tukadoji Maharaj Nagpur University, and Renata Manconi, also of the Dipartimento di Medicina Veterinaria at the Università di Sassari, describe a new species of Freshwater Sponge from the Deccan infratrappean deposits of Naskal in Telangana State, India.

The Deccan Traps are a series of Late Cretaceous-Early Palaeocene volcanogenic sediments covering an area of 500 000 km² across southern, western, and central India. As well as the numerous lava flows of these deposits, the sequence also includes infratrappean and intertrappean sediments (that is to say sediments covered over by lava flows, or between lava flows), which provide a fossil record of many organisms across the Cretaceous-Palaeocene boundary. The Naskal site is located in the Ranga Reddy District of Telangana State, in south-central India. This sequence is less than 3 m deep, and has a lateral extent of less than 15 m, and exposes sediments laid down between flows 3 and 4 of the Deccan Traps sequence, which have been dated to between 66.136 and 66.056 million years before the present, slightly below the Cretaceous-Palaeocene Boundary, at 66.043 million years ago.

Within the total Naskal exposure, Sponge spicules were found only at one site, Naskal GSI Quarry, within a portion of the exposure 120 mm thick. The spicule-yielding section includes exposures of (bottom-to-top) black to grey cherty limestone, hard yellowish shaly mudstone, loose shaly to carbonate mudstone to marlstone, white mudstone, and dark clay with sandy lenses. No spicules were recovered from the Naskal B exposure, which is only 7 m from the Naskal GSI Quarry exposure.

Map of India showing Deccan volcanic province (green area). (A) Location of Naskal intertrappean, Naskal B (white star) and Naskal GSI Quarry sections (red star). (B) Sponge spicule and Diatom bearing horizon in Naskal GSI Quarry section. (C) Palynomorph bearing Naskal B section. Samant et al. (2023).

The Naskal exposure is noted for its Mammal fauna, but also includes Fish, Anurans, Squamates, a Sphenodontian, Turtles, and Crocodilians. Pollen recovered from Naskal contain a mixture of forms which are known in both Cretaceous and Palaeocene deposits, as well as forms that are otherwise exclusively Cretaceous or exclusively Palaeocene.

Samples were obtained by acid-washing bulk sediment samples that sieving the remnants, and examining the filtered samples under light and scanning electron microscopes.

The specimens are placed in a new genus and genus, and given the name Longibirotula antiqua, where 'Longibirotula' refers to the long shaft of the birotules (a type of spicule with wheel-shaped ends), assumed to be gemmuloscleres, which would have produced gemmules, which in turn would have acted as a resting stage for these Sponges, and 'antiqua'  means 'old'. The distinctive birotules of this species and long and slender, reaching 47-76 μm in length, straight or slightly curved, and have scattered spines, which very in their density and number. 

Gemmuloscleres of the Palaeospongillid Sponge Longibirotula antiqua from the Upper Cretaceous–Lower Paleocene of Naskal GSI Quarry (India). (A)–(O) Birotules (slides PGNU/NSKQ/SL-1–13) slender, spiny, with long shaft. Diagenetic processes affect all spicules to various degree. Scale bars 20 µm. Samant et al. (2023).

Longibirotula antiqua also has two types of monaxial megascleres (large unbranching spicules), slim long, microspiny to smooth oxeas (needle shaped spicules) reaching 142-425 μm in length, and shorter, stouter acanthoxeas (spiny spicules) measuring 71-105 μm in length.

Megascleres of the Palaeospongillid Sponge Longibirotula antiqua from the Upper Cretaceous–Lower Paleocene of Naskal GSI Quarry (India). (A)–(I). Oxeas (slides PGNU/NSKQ/SL-1–13) slim to stout with variably pointed tips. Diagenetic processes affect all spicules to various degree. Scale bars 20 µm. Samant et al. (2023).

The spicules of the Sponge are associated with diatoms of the genus Aulacoseira, which implies a eutrophic (nutrient rich) environment, possibly caused by volcanic material entering the lake. The presence of gemmuloscleres birotules suggests that the lake was only sporadically a suitable environment for the Sponges, possibly due to seasonal variations in water level. Gemmulation, timed to match seasonal conditions, is considered to be a key evolutionary strategy for Freshwater Sponges, the the gemmules forming asexual propagative agents which can survive periods of adverse conditions and disperse to colonize new environments.

Megascleres of the Palaeospongillid Sponge Longibirotula antiqua from the Upper Cretaceous–Lower Paleocene of Naskal GSI Quarry (India). (A)–(H) Acanthoxeas (slides PGNU/NSKQ/SL-1–13) with large spines. Diagenetic processes affect all spicules to various degree. Scale bars 20 µm. Samant et al. (2023).

Gemmules (often used as the diagnostic feature for Freshwater Sponge species) for Longibirotula antiqua have not been found in the Naskal deposits, but the distinctive combination of long slim oxeas, shorter acanthoxeas and long gemmuloscleres birotules, and an absence of microscleres (a smaller class of Sponge spicules), leads Samant et al. to conclude that the material is sufficiently unique to be described as a new species. 

Fossil Freshwater Sponges of the Eocene-Miocene genus Ephydatia have gemmuloscleres birotules, as do members of the modern genera Anheteromeyenia, Corvoheteromeyenia, Corvomeyenia, Heteromeyenia, Racekiela, and Umborotula. The birotules of Longibirotula antiqua most closely resemble those of Ephydatia and Heteromeyenia, giving Samant et al. confidence that these are in fact gemmuloscleres. 

Spicular complement of skeleton and gemmules of the Palaeospongillid Sponge Longibirotula antiqua from Upper Cretaceous–Lower Paleocene of Naskal GSI Quarry (India) (slides PGNU/NSKQ/ST-1, 2). (A), (B) Acanthoxeas short with dense spines. (C), (D) Oxeas fusiform, long and with acute tips. (E), (F) Birotules with long shaft. Diagenetic processes affect all spicules to various degree. Scale bars 20 µm. Samant et al. (2023).

The smooth to microspiny long oxeas of Longibirotula antiqua resemble those of the extant genus Heterorotula. The short acanthoxeas are less similar, but still close enough that Samant et al. suspect that like Heterorotula, Longibirotula antiqua may have used these shorter spicules to form a gemmular cage, protecting its resting stage. The genus Heterorotula has a broadly Gondwanan distribution, with living species known from Australia, New Zealand, New Caledonia, and the Americas, as well as a fossil record in subequatorial Brazil (although it is absent from the Afrotropical Region), which likely suggests that Longibirotula antiqua was derived from Freshwater Sponges from India rather than Eurasia.  The similarity of Longibirotula antiqua to modern members of the group underlines the structurally conservative nature of Freshwater Sponges, as well as the success of a morphology and lifestyle which has apparently been able to persist with little change for tens of millions of years.

See also....

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

Haliclona (Flagellia) xenomorpha: A new species of Heteroscleromorph Demosponge from the Gulf of St. Lawrence, Canada.

Demosponges are the most abundant class of Poriferans in modern waters, with 72% of living Sponge species being Demosponges. They are characterised by a soft body covering a skeleton made up of spicules of calcite or aragonite. Members of the subclass Heteroscleromorpha also have silica spicules, but these are morphologically distinct from those of Glass Sponges, taking the form of monaxons (needle shaped spicules) and/or tetraxons (four-pointed spicules), as well as microscleres (small skeletal elements which are often highly distinctive at species level). The order Haplosclerida consists of Heteroscleromorph Sponges with skeletons comprised largely of oxeas monaxons pointed at both ends) and strongyles (monaxons with blunt ends), plus distinctive microscleres. The family Chalinidae are common marine encrusting Haplosclerid Sponges, found in protected environments as undersides of rocks and crevices, both in intertidal and subtidal habitats. The largest genus in the family Chalinidae is Haliclona, which contains over 350 species, and has been divided into numerous subgenera. Haliclona (Flagellia) is a recently erected subgenus characterized by the presence of flagellosigma microscleres (small, horseshoe-shaped spicules), which are often distinctive between species. Members of the taxon also have normal sigmas within a confused skeleton formed by oxea megascleres. The subgenus has a global distribution and contains 10 species. 

In a paper published in the journal Zootaxa on 14 May 2020, Curtis Dinn of the Gulf Fisheries Centre of Fisheries and Oceans Canada, describes a large and abundant new species of Haliclona (Flagellia) collected throughout the southern Gulf of St. Lawrence, Canada.

The new species is named Haliclona (Flagellia) xenomorpha, where 'xenomorpha' means 'Alien-shaped' in reference to the thick and often irregular flagellosigmas. These spicules also resemble the derelict spacecraft from the 1979 film Alien directed by Ridley Scott, and the name pays homage to the titular antagonist of the series. This species is massively encrusting with raised oscula (large openings to the outside through which the current of water exits after passing through the spongocoel, having been absorbed through much smaller dermal pores). The Sponge is very friable and is thus often broken into pieces upon collection. The largest specimens are over 10 cm in diameter, but no consistent growth form is apparent. Larger specimens are often seen fully encrusting small pebbles and may have shell fragments incorporated into the tissue. The surface is generally smooth in more intact specimens, while fragments are more irregular and porous. In less damaged specimens, a fine transparent mesh covers the surface, but this often collapses after collection. Oscula are less than 0.5 cm wide and are raised above the surrounding tissue. Below the surface, the Sponge tissue is irregularly punctate. The consistency of large pieces is firm, compressible, but very brittle if pressure is applied, resulting in small crumbled pieces. The colour is pale yellow to light brown, with some specimens appearing pinkish.

Haliclona (Flagellia) xenomorpha. (A). Holotype ARC 81426. (B) Paratype ARC 81428 showing portions of smooth surface. (C) Specimen with smooth surface along an inner portion. (D) Large multispecies catch with Haliclona (Flagellia) xenomorpha (white arrows) and Mycale lingua (black arrows). (E), (F) Skeleton. Dinn (2020).

The skeleton of Haliclona (Flagellia) xenomorpha is confused, with a loose reticulation of paucispicular tracts which are irregularly connected by single spicules. Thick and thin oxeas do not appear to be localized in the skeleton. There is no surface specialization of spicules, but a layer of thick spongin is present at the surface in undamaged specimens. Flagellosigmas and sigmas are found throughout the choanosome, with regular sigmas often occurring in groups, especially evident near canal openings.

Megascleres (large spicules) are oxeas in two size categories. Thick oxeas are often slightly bent and have sharp tapered points, 250-298 × 12-17 μm. Thin oxeas are similarly shaped but with sharper ends which taper further along the shaft, 183-245 × 3.6-9.0 μm. Microscleres are flagellosigmas in two size categories and abundant normal sigmas. The distinctive thick category of flagellosigmas consists of spicules with curved ends that may be steeply curved, branched into two or more points, or not curved at all with endings pointing outwards, length of long endings 56-108 μm, of short endings 46-73 μm, width 58-98 μm, thickness 6.5-13 μm. Normal flagellosigmas are ovoid with widely curved ends, but are variable in size and overall shape, length of long endings 32-95 μm, of short endings 26-56 μm, width 40-77 μm, thickness 2.7-5.6 μm. Regular sigmas are variable in size, and have incurved apices, 39-82 μm in length and 3.2-7.1 μm thick. In some specimens thick flagellosigmas may appear more sigma-like with ends of similar lengths and a crescent shape, but these spicules may also have irregular ends.

Haliclona (Flagellia) xenomorpha, spicules. (A)–(B). Oxeas. (C)–(F) Thick flagellosigmas showing various degrees of irregularity. (G)–(H) Regular flagellosigmas. (I)–(J) Regular sigmas. Dinn (2020).

Several specimens of Haliclona (Flagellia) xenomorpha were collected along the American Bank near the Gaspé Peninsula and southern fringe of the Laurentian Channel. The holotype (when describing a new species one specimen is designated the holotype; all future specimens determined to belong to the same species as this holotype therefore bellong to the species) was collected north of Brion Island, in the Magdalen Island Archipelago, near the shelf edge and was encrusting a rock. The species was collected at depths ranging from 41–89 m. Multiple specimens were collected in single trawls, but only single individuals from trawls were retained for taxonomic analysis.

The unique features of Haliclona (Flagellia) xenomorpha are the presence of thick flagellosigmas and two categories of oxeas. The thickness of the flagellosigma spicules exceed, and in most cases more than double the maximum thickness of spicules from other members of the genus. The flagellosigmas in Haliclona (Flagellia) xenomorpha reach a maximum thickness 13 μm, while flagellosigmas of Haliclona (Flagellia) porosa (also present in the Gulf of St. Lawrence) reach a maximum thickness of 6.3 μm. Thick flagellosigmas are common in the skeleton, and are thus considered as a second size category, though there may be intermediately sized flagellosigmas which are difficult to place in either size category. The consistently irregular endings of the thick flagellosigmas are also a defining character of the species.

See also...

Follow Sciency Thoughts on Facebook.

Chalinula qatari & Suberites luna: Two new species of Demosponge from the hyperarid Mangroves of Qatar.

The Persian Gulf is considered an extreme marine environment due to its hyperthermic and hypersaline conditions. The environment in the southwestern coast of the Persian Gulf is particularly extreme. This shallow-water region and the associated mangrove settings has hyperarid conditions with temperature and salinity reaching values as high as 49˚C and 75 parts per thousand, levels much higher than the East coast of the Gulf. The southwestern coast forms an isolated marine province with a high rate of marine endemism and lower species richness than the eastern coast of Persian Gulf, the latter receives an influx of waters from the Indian Ocean which results in a higher diversity of species. The high rate of endemism found in the western coast of Persian Gulf, and the as yet, low number of taxonomic descriptions for the region, indicate potential for the discovery of species new-to-science.

In a paper published in the journal PLoS One on 13 May 2020, Bruno Welter Giraldes of the Environmental Science Centre at Qatar University, Claire Goodwin of the Huntsman Marine Science Centre and the University of New Brunswick, Noora Al-Fardi, Amanda Engmann, and Alexandra Leitão, also of the Environmental Science Centre at Qatar University, Asma Ahmed, Kamelia Ahmed, Hadil Abdulkader, and Halah Al-Korbi of the Biomedical Science Department at Qatar University, Hala Sultan Saif Al Easa of the Department of Chemistry and Earth Sciences at Qatar University, Nahla Ahmed Eltai of the Biomedical Research Centre at Qatar University, and Pejman Hanifi-Moghaddam, also of the Biomedical Science Department at Qatar University, describe two new species of Demosponge from the Mangroves of Qatar.

Marine ecosystems have considerable potential for bioprospecting, and several new drugs are described and isolated every year, yet these natural resources, which can produce economic and societal benefits, remain largely unexplored. A significant majority of new marine natural products have come from Sponges (Phylum Porifera). Chemical compounds isolated from Sponges have been found to have anti-inflammatory, antibiotic, anticancer and anticoagulant properties. Sponges are multicellular invertebrates that have evolved as filter feeders in aquatic environments. Sponges naturally process a huge volume of water daily and as a consequence, may concentrate a wide variety of pathogens. Due to this, Sponges have developed effective defence systems based on bioactive secondary metabolites including antibacterial substances.

Despite their economic importance, virtually nothing is known about Sponge diversity in the coastal areas in the Gulf, with only a few Sponge records from the Arabian Sea and adjacent area. Environmental stress has been shown to concentrate toxins in Sponges, and higher temperatures to be related with the bioactivity. Therefore, the study of marine Sponges in the extreme, hyperarid conditions found in the Southwest of Persian Gulf has potential for both the discovery of potential bioactive metabolites and species new to science.

Shallow-water hyperarid Mangrove ecosystems were studied at Al-Khor and Al-Dhakira, Qatar. These areas do not experience any input of fresh water, but saline tidal channels are present. Areas of Seagrass and Oyster beds, interspersed with rocky substrate, surround and extend out from the Mangroves in the shallow subtidal zone (less than 1 m). The coastal zones of Qatar are characteristic by gently sloping shores and a large tidal range which result in large intertidal and shallow subtidal zones.

Collection localities in Qatar: (A) the location of Qatar within the Persian Gulf; (B) the location of the studied Mangrove settings and the other locations around Qatar that were searched for Sponge species; (C) the studied Mangrove settings in Al-Khor and Al-Dhakira highlighting the large area with shallow depth around the Mangrove; (D) schematic profile of the Mangrove ecosystem in the coastal intertidal zone with the forest area and the shallow subtidal zone with patches of Seagrass and Oyster-beds (rocks). Giraldes et al. (2020).

Sponges were collected in the intertidal and subtidal zones in the studied arid Mangrove ecosystem. Most specimens were collected by snorkelling and freediving at the edge of tidal mangrove channels. Field studies did not involve endangered or protected species and there is no specific permission required for collection of Porifera in these locations. Specimens were photographed in situ using underwater cameras. Large pieces of each species were transported to the laboratory and preserved in 70% ethanol. Methods for identification followed standard taxonomic procedures.

After the first taxonomic identification, more than 50 freediving and snorkelling expeditions were performed in the tidal channels surrounding Mangroves, and Seagrasses, to identify zonation and distribution of the described species. In addition several dives were undertaken in shallow subtidal zones around Qatar, including Um-Bab, Dukhan and Janan Island in the west Coast, Shamal, Al-Ruwais and Fuwarit in the North coast and Al-Khor, Al-Dhakira, Doha, Al-Alyia Island, Al-Wakrah and Sea-Line in the east coast. Visual identification of Sponges was performed based on the general shape, texture and colour of the described new species.

The first new species described is placed in the genus Chalinula, and given the specific name qatari, for the general type locality, Qatar, and its colouration, which is similar to that of the Qatari flag. Chalinula qatari is a thinly encrusting Sponge with a thickness of around 4 mm and a maximum observed diameter of 40 cm. Oscular chimneys  (raised oscula, large openings to the outside through which the current of water exits after passing through the spongocoel, having been absorbed through much smaller dermal pores) were present on some specimens. These had the form of small cones around 6 mm in diameter with an elevation of around 8 mm. Oscules were 2–5 mm in diameter. Oscular chimneys were observed mainly in the specimens in the Mangrove roots. Most living specimens are a vivid maroon colour, however, those living in stressful situations, such as intertidal specimens in summer conditions, may bleach to a pale yellow. The choanosomal skeleton (supporting skeleton of spicules) is an anisotropic reticulation with paucispicular primary tracts, 1–3 spicules in diameter. The secondary tracts are unispicular, usually about two spicules long. There is no ectosomal skeleton, the ends of the primary tracts of the choanosome project beyond the surface, rendering it slightly hispid.

Chalinula qatari, morphology, skeleton and spiculation. Morphology: Living specimens (A) attached to Mangrove pneumatophores in the riparian zone, (B), (C) in the intertidal zone, (D) under limestone in the channels between the Mangroves. Skeleton and spicules: (E) choanosomal skeleton; (F) embryos; (G) ascending spicule tracts; (H) oxeas, showing immature thinner forms; (I) choanosomal skeleton showing thickness of encrustation on a Mangrove root; (J) embryo; (K) Cross section of ectosome (specialised ectosomal skeleton absent); (L) choanosomal skeleton showing length of secondary spicule tracts; (M) close up of ascending primary spicule tract. Electronic microscopy of (N) large, thick oxea (O) thinner oxea. Giraldes et al. (2020).

Chalinula qatari is currently only known from the holotype and paratype localities in the Mangroves at Al-Dhakira and Al-khor, planted Mangrove in the Al-Wakrah in the south of Doha, and in the Mangroves at Shamal in the north-east of Qatar. All locations are on the east coast of Qatar, south-western coast of the Arabian/Persian Gulf. 

Chalinula qatari is described from a holotype (when describing a new species one specimen is designated the holotype; all future specimens determined to belong to the same species as this holotype therefore bellong to the species) collected from a pneumatophore (breathing root) of a Mangrove in a tidal-channel at Al-Khor, Qatar, at a depth of 30 cm, as well as two paratypes from the intertidal zone at Al-Dhakira, also found encrusting pneumatophores.

Extracts from Chalinula qatari did not show any antibacterial bioactivity against the test pathogens. No significant differences in skeletal morphology or spiculation were observed between the paratypes. The proportion of smaller young oxeas did vary amongst the paratypes; with each specimens presenting a different ratio of large and thin spicules. Embryos with young spicules were visible in some individuals. these were always concentrated in the basal layer. The skeleton of Chalinula qatari comprises oxeas (spicules pointed at both ends) 69.2-96.2 μm in length by 1.1-4.0 μm in width.

The species was found growing on the pneumatophores of the Mangrove Avicennia marina in the intertidal and subtidal zones along tidal channels, and on the underside of limestone rocks in tidal channels. It was also found in Seagrass and Algal beds connected directly with the Mangrove habitat. Chalinula qatari is currently only known from the holotype and paratype localities in the Mangroves at Al-Dhakira and Al-khor, as well as planted Mangroves in the Al-Wakrah in the south of Doha, and in the Mangroves at Shamal in the north-east of Qatar. All locations are on the east coast of Qatar, south-western coast of the Persian Gulf.

The possession of an isodictyal skeleton of diactinal megascleres, and a regular anisotropic reticulation with recognisable ascending primary tracts, places this species in Order Haplosclerida. The presence of a choanosomal skeleton with unispicular secondary lines assigns this species to Family Chalinidae. Within the Chalinidae, Giraldes et al. assign this species to genus Chalinula on the basis that the secondary tracts of the choanosomal skeleton are mostly two spicules long and multispicular fibre tracts are not present throughout the Sponge. 

The second new species is placed in the genus Suberites, and given the specific name luna; the species was nicknamed the ‘Moon-surface Sponge’ by the collectors due to its appearance. The name reflects both this and the importance of the Moon in the Muslim culture.

Suberites luna, morphology, skeleton and spiculation: (A), (B) growing on Mangrove pneumatophores in the riparian zone; (C) just collected and cut; (D) large compound oscule; (E) large specimens close to Seagrass; (F) specimen just collected. Slides of fresh specimens, (G) cross section of choanosomal skeleton; (H) plumose choanosomal skeleton in cross section, (I) palisade of subtylostyles in the ectosome. Slide in cross section of dried specimen showing plumose choanosomal skeleton (J). Electronic Microscopy, (K), (L), (M) showing different head shapes of the subtylostyles; (N) the subtylostyles types (I), (II) and (III). Giraldes et al. (2020).

Suberites luna is a massive globular-lobate sponge, with some large specimens 20–60 cm diameter and 10–20 cm high. The sponge exterior is dense and compact. The interior choanosomal tissue has many pores and is cavernous. Oscules are infrequent, the largest observed was around 8 mm in diameter and was on the apex of a lobe. These Sponges have a velvety surface with macroscopically smooth appearance; they are cmpact, firm, slightly compressible and elastic, and hard to tear. A slime is produced when torn.  The live colour is greenish-black and internally a yellowish orange.

The skeleton is plumose (made of primary fibres or spicule tracts from which skeletal elements obliquely radiate) with ascending tracts of large subtylostyles (slender accessory spicules). An ectosomal skeleton is formed of a palisade of smaller subtylostyles. Subtylostyles are 10-843 μm by 2.9-13.1 μm. A multimodal pattern of spicule length was observed, with three main sizes of tylostyles (subtylostyles): (I) smaller spicules 110-196 long by 2.9-5.9 μm wide, most likely ectosomal in distribution; (II) robust subtylostyles 400–500 long by 5-13.1 μm wide, found in the sub-ectosomal choanosomal skeleton; (III) long subtylostyles, over 600 μm in length by 5.6-10.4 μm wide, part of the deep choanosomal skeleton forming the ascending tracts in the plumose skeleton.

Suberites luna has been recorded from Mangrove ecosystems on the east coast of Qatar from Shamal to Al-Wakrah, in the south-western coast of the Persian Gulf. The species is described from a holotype collected from the pneumatophore of a Mangrove in a tidal channel at Al-Khor, Qatar, and four paratypes, one collected from a rock/sand substrate in the hyperarid Mangrove bay at Al-Khor, and three collected from shells and soft rock on sand substrate in the Seagrass peripheral to the hyperarid Mangrove at Al-Dhakira, Qatar. 

Suberites luna is found on hard substrates in Mangrove and Seagrass habitats in the subtidal zone. Observed on the pneumatophores of Avicennia marina in the channels of the riparian zone of the arid Mangrove ecosystems. Often found close to Chalinula qatari. Very abundant with large specimens (more than 50 cm diameter) in the subtidal zone around the Mangroves, and at the edges of the seagrass habitat. Found in soft sediment, but mostly attached to small pieces of hard substrate within the sediment, such as small soft-rocks and shells. There was a higher abundance of this species at sites with low current.

Significant differences in skeleton and spiculation of the paratypes was not observed. However, there was some variation in external form with some specimens being much larger and more lobate than others. This species is included within the Family Suberitidae and Genus Suberites, due to its massively globular-lobate shape, possession of a spicule complement consisting only of tylostyles, and the presence of an ectosomal palisade formed of bouquets of smaller tylostyles than those of the choanosome.

Extracts taken from some specimens of Suberites luna showed antibiotic activity against three species of bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis), others were effective against only one species (Enterococcus faecalis) of the bacteria tested in Giraldes et al.'s study, while others showed no antibacterial activity against any of the bacterial strains.

The discovery of Suberites luna and Chalinula qatari on Mangroves on the west coast of the Persian Gulf highlights the lack of taxonomic study of Sponge species in the Gulf but also the biogeographic isolation of the studied hyperarid mangrove habitats. These two species new to science, together with the other endemic species that have been found in this habitat support the concept that the west coast of the Persian Gulf is an isolated marine province. Theoretically, the intense hyperarid conditions found in the west coast of Persian Gulf create a biogeographic barrier that isolates an endemic biodiversity adapted to the intense temperature and salinity conditions. The deeper waters and constant water input from the Indian Ocean result in less extreme arid conditions on the eastern coast of the Persian Gulf, and this area shares several species with tropical Indian Ocean areas (e.g. Gastropods and Decapods). The high temperatures and salinities found on the western Persian Gulf coast might kill non-adapted Sponge species, as has been demonstrated for tropical Sponge species reaching 33˚C, preventing colonisation by Sponges from neighbouring provinces. Recent studies on the biodiversity of bioturbating Crabs, based in the same arid Mangrove setting, support the theory that the southwest coast of the Persian Gulf is an isolated marine province. A Mangrove setting in an isolated marine province that houses an abundant endemic Shrimp Palaemon khori, that occurs only in this Mangrove setting in Qatar and remains absent in the entire Arabian Gulf. It is possible the two new Sponge species are also endemic to this Mangrove setting in the type locality. If they are it would bring the number of endemic species known to three. This highlights the conservation importance of this forest ecosystem in a desert region. Further study of the western Persian Gulf sponge fauna is needed to fully understand its biodiversity and biogeographic affinities with neighbouring regions.

Suberites luna exhibited antibacterial activity against three common pathogenic Gram-positive Bacterial species, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. Although this is a preliminary study it highlights the potential of the toxins produced by Suberites luna for the development of a new antibacterial drugs, including drugs for resistant Bacteria. Future studies are required to chemically isolate the toxin of Suberites luna  and evaluate its uses in treatment of Bacteraemia and other Bacterial infections. Despite the negative antibiotic effect of Chalinula qatari the fact other studies on the family Chalinidae have found metabolites indicate that it might merit future research. The sulphated sterol Chalinulasterol, has been isolated from the family Chalinidae.

See also...

Follow Sciency Thoughts on Facebook.