DEEP-SEA OF THE MEDITERRANEAN SEA

SPONGES SILICEOUS SPONGES – CLASS DEMOSPONGIAE GLASS SPONGES – CLASS HEXACTINELLIDA (PHYLUM , also known as siliceous sponges, represent the largest and most diverse class within Porifera, comprising 85%, more than 6 600, of all species. Their shape and size range from thin crusts, to various sizes Hexactinellids, also known as glass sponges, constitute a predominantly of globular, vase-, cushion-, tree-like and giant barrels more than 2 m high. Coloration, derived from pigments or symbiotic associates, covers a wide spectrum (from white to black) including yellow, orange, red, blue, green, deep-sea group, typically occurring at bathyal and abyssal depths (i.e. below PORIFERA) purple, brown, etc. Consistency depends on the skeletal composition and varies between soft, compressible, elastic, to tough and rock hard. The surface texture varies from smooth, velvety to rugose, and hispid. Approximately 200 m). They are exclusively marine and comprise approximately 675 species Sponges are amongst 670 species are known to occur in the Mediterranean Sea. worldwide, of which nine occur in the Mediterranean Sea. Their external the most ancient morphology usually varies between vase, blade, cup or tube-shaped and both Massive, hard sponges (Geodia spp.) Globular sponges with rooting structures (Thenea muricata) Lollipop sponges to have appeared in the stalked and non-stalked forms exist. They attach to hard bottom using a basal disc or anchoring spicules, or to soft sediment by means of root-like structures. world’s oceans. Currently, Massive sponges Globular to egg- Lollipop-shaped coming in a variety of shaped sponges sponges with Coloration is mostly in shades of white, beige and yellow. more than 8 000 species shapes, from irregular with one or few a large, circular are recognized but over to convoluted masses; apical oscules. They (Stylocordyla Birds’ nest sponge (Pheronema carpenteri) 25 000 are estimated to younger specimens are are characterized pellita) to oval and usually (sub)spherical. by a distinct apically compressed Globular to sub- exist. They are distributed Oscules are grouped groove around the (Rhizaxinella cylindrical sponges together and located mid‑section of the pyrifera) “head” and possessing a wide and at all depths and latitudes, in depression areas body, where inhalant a slender stalk. One deep atrial cavity with and in some areas form located on the top pores (ostia) are oscule is visible at a large apical oscule. surface of the sponge. located, and root-like highly structured habitats the top of the head. The surface is “hairy” Small inhalant pores structures projecting Thenea muricata Geodia barretti Geodia cydonium S. pellita, grey or Stylocordyla pellita Rhizaxinella pyrifera and shows an intricate known as sponge grounds, (ostia) are also grouped from the base, by cream in colour, has a smooth and flexible stalk, and is attached to hard substrates by means of network of spicules. aggregations, gardens or together but found distributed across the overall surface. G. barretti, cream in colour, has an even means of which they attach to soft substrate. Consistency is slightly compressible and texture is Texture is fibrous and and clean surface with a rubbery texture. G. cydonium, yellow in colour, has a hispid/harsh surface a rounded disc while R. pyrifera, dull yellow, has an occasionally knobbed or branched rigid stalk, smooth. Colour is white to brownish/greyish. compressible. It is reefs, particularly so in the often covered with sediment. Both species have a tough but slightly compressible consistency. and lives in soft sediment thanks to a branching root-like structure. deep‑sea. These habitats attached to the substrate Size: up to 50 cm in diameter Depth and substrate: 300–2 000 m; mixed or rock Size: up to 5-6 cm in height/diameter Depth and substrate: 300–2 000 m; sand or mud Size: less than 15 cm in height Depth and substrate: 250–800 m; sand or rock by means of a basal tuft Pheronema carpenteri play key ecological roles of spicules. Can be found in large numbers as the only species or alongside other sponge species, i.e. such as: serving as shelter it forms sponge aggregations. and nursery, and providing Stalked, fan-shaped sponges (Phakellia spp.) Fan-shaped, white and orange sponges (Pachastrella, Poecillastra) Globular sponges with apical oscula (Suberites spp.) Size: up to 20 cm in height Depth and substrate: 300–2 000 m; on soft or mixed substrate food for numerous other Thin, cup- or fan-shaped Laterally flat, Globular sponges attached to massive sponges species of invertebrates sponges Felt vase sponge (Asconema setubalense) and fish; mediating the the substrate by a fairly with a hard but with usually narrow stalk, with a friable consistency one large Vase sponge with a transfer of energy between smooth surface and and a rather thick apical oscule. thin fibreglass-like wall, the benthic and pelagic small oscules on one appearance. Surface Some species folding outwards at the side. Specimens of more or less smooth (e.g. S. ficus) top. Colour is off-white Phakellia ventilabrum are systems; and participating with flat, visible have a short to grey or brownish whitish beige and have in biogeochemical cycling oscules. Pachastrella and thick with sediment. When thin and frayed edges monilifera is light processes. Unlike most peduncle. collected by dredge/ with a characteristic coloured, whitish, trawl, the appearance pattern of vein-like lines Consistency other animals, sponges Phakellia ventilabrum Phakellia robusta more hispid and Pachastrella monilifera Poecillastra compressa Suberites domuncula S. ficus Suberites sp. can be that of “felt” fanning out. is firm yet often partially shreds. Can be found lack true tissues or Phakellia robusta is rather similar but has a more ochre-yellow coloration, a thicker blade and more slightly compressible. The surface is even and velvety. Colour varying from yellow to orange, red covered by sediment. Poecillastra compressa is usually bright orange, although whitish specimens in large numbers, textured surface. They are both quite flexible. and brown. S. domuncula frequently associated to hermit crabs shell. organs. Instead, they have are known. It has larger oscules concentrated on one of the two sides. Occasionally cup-shaped. i.e. it forms sponge specialized cells carrying Size: up to 30 cm in height/width Depth and substrate: 200–800 m; rock, gravel beds Size: up to 20 cm wide Depth and substrate: 50–800 m; rock, coral rubble Size: up to 10 cm in diameter Depth and substrate: 0–800 m; mixed; S. domuncula aggregations. Asconema setubalense out specific functions and frequently associated to hermit crabs shell a body arranged around Size: up to 1 m in height Depth and substrate: 300–2 000 m; on soft or mixed a canal system that filters Mediterranean stony sponge ( ficiformis) Massive, volcano-like sponges (Haliclona magna) Light coloured conulose sponges (Dysidea spp.) substrate water for food and oxygen. Massive lobose A massive, whitish sponge with Cushion-shaped, sponges with large tubular or conical processes at somewhat lobose, White bouquet sponge (Farrea bowerbanki) large sharp- times covered by sediment or by a sponges. Oscules, Thin-walled reticulated tubes branching outwards edged oscules on film giving it a purple- variable in size from a basal attachment point to form a globular the upper side. brownish coloration. Processes (depending on the “bouquet”. The tubes are open and increasingly wider Consistency is often with one or few major oscules species), are usually and wavy at their extremity. Consistency is hard but hard but slightly reaching a large diameter. The rim of scattered around the fragile and texture is like fine sand paper. Coloration is compressible, the oscules is thinner and somehow sponge. The surface crisp white. crumbly inside. transparent. Texture is smooth and is “spiky” (conulose) Texture is velvety. consistency is soft turning brittle due to the lifting Outer coloration when dried. of the surface layer varies from dark Dysidea avara Dysidea sp. Petrosia ficiformis Petrosia ficiformis by spongin fibres. red/burgundy (in (burgundy morph) (white morph) shallower areas) to Consistency is elastic. Coloration whitish to yellowish but some species have a pink, violet or off-white (in deeper and darker areas) whereas inner coloration is always off-white. Haliclona magna bluish tinge. The spikes are usually lighter in colour than the rest of the sponge.

Size: up to 50 cm across Depth and substrate: 0–800 m; rocky bottom Size: up to 40 cm in height Depth and substrate: 130–300 m; rock Size: up to 20–30 cm across Depth and substrate: 0–300 m; rocky bottom Farrea bowerbanki Size: up to 30 cm diameter Depth and substrate: 300–2 000 m; on rocky substrate

Massive, tubular gold sponges (Aplysina spp.) Arborescent yellowish sponges (Antho dichotoma) Lamellate rock sponges (Leiodermatium pfeifferae) White funnel with finger-like projections (Aphrocallistes beatrix) The only exception are Massive sponges Stalked arborescent sponge, Erect sponges with a lamellate shape, with a cushion-like dichotomously branched (i.e. each from irregular to convoluted masses. Funnel-shaped sponge the carnivorous sponges base from which branch splits into two). The branches The convex (inhalant) side of the plate with lateral finger-like (family Cladorhizidae) several finger-like are flexible, much more so than the has many small evenly-distributed projections often directed that feed directly on tubes project. The stalk. Oscules are not clearly visible. ostia, whereas the concave (exhalant) towards the base. The top tubes are somewhat Consistency is firm and texture is side has fewer larger elevated oscules. of the sponge is covered small crustaceans. The flattened at the finely hispid. Coloration is yellowish Consistency is rock-hard and texture is with a rigid network-like sponge skeleton is made top and bear a to light brown. rough. Colour is off-white to light brown plate. The surface has a single large oscule. sometimes presenting a light blue tinge. very characteristic regular up of mineral (siliceous or Consistency is hexagonal honeycomb calcareous spicules) and/or somewhat flexible appearance. Consistency is organic (spongin, collagen) and compressible. Aplysinia cavernicola Aplysina aerophoba hard but fragile and texture Texture is rubbery (freshly collected) (upon air exposure) is like rough sand paper. Live elements, although a few and slightly rugose. Colour is golden yellow when fresh, turning to greenish-blue black after a few coloration is bright white, Aphrocallistes beatrix Aphrocallistes beatrix species lack a skeleton minutes of exposure to air. Antho dichotoma Leiodermatium pfeifferae whereas dead tissue appears brown. (top view) (lateral view) altogether. The surface Size: up to 25 cm in height Depth and substrate: 0–300 m; rocky bottom Size: up to 30 cm in height Depth and substrate: 0–800 m; rocky bottom Size: up to 1 m across Depth and substrate: 300–2 000 m; mixed or rock Size: up to 20 cm in height Depth and substrate: 300–2 000 m; on hard substrate, of the sponge holds often over corals or other sponge skeletons numerous inhalant and exhalant pores, known as Pine-tree sponge (Cladorhiza abyssicola) ostia and oscules, through SIMILAR LOOKING GROUPS (ALGAE, ANTHOZOANS, BRYOZOANS, ASCIDIANS) ACKNOWLEDGEMENTS Erect sponge resembling a pine-tree, The authors of this poster are Joana Xavier (Biology Department which the water enters with a central axis from which several and K. G. Jebsen Centre for Deep-Sea Research, University of and exits the sponge. branches depart. Each branch may Branched, arborescent and have secondary branches. Both flexible sponges can be easily Bergen, Noeway) and Marzia Bo (Dipartimento per lo Studio del Species identification is Territorio, dell’Ambiente e della Vita, University of Genoa, Italy). the axis and branches carry thin misidentified as gorgonian corals, primarily based on the filaments projected in all directions. Numerous scientists are to be acknowledged for their helpful It attaches to the substrate by means but a close look will evidence comments and for image supply: Caterina Longo and Frine analyses of the skeleton, of root-like structures. Consistency the lack of polyps (one of the Cardone (University of Bari), Maurizio Pansini and Marco Bertolino alongside with external is firm, the branches are stiff and the principal body form occurring (University of Genoa), Manuel Maldonado (CSIC Blanes), Jordi characteristics. Sponges texture is a bit harsh. White in colour. in the group of corals and Grinyó, Carlos Dominguez, and Andreu Santín (CSIC Barcelona), are divided into four Francisca Carvalho and Jon Hestetun (University of Bergen), represented by a column with a Claudio Lo Iacono (National Oceanography Centre Southampton), classes, of which two, crown of tentacles). Rock sponges Jean Vacelet, Nicole Boury-Esnault, and Maïa Fourt (IMBE and the Demospongiae and Cladorhiza abyssicola are similar to scleractinian corals, Aix-Marseille Université), Paco Cárdenas (University of Uppsala), Hexactinellida, are the most whereas glass sponges with a Gorgonian Gorgonian Coralline algae Coralline algae Ascidian Bryozoan Vasilis Gerovasileiou (HCMR Heraklion), Eleni Voultsiadou (AUTH Size: up to 20 cm in Depth and substrate: 300–2 000 m; rigid, reticulated and white skeleton can be mistaken for hard corals and bryozoans. Globular, rigid sponges can be misidentified as contracted solitary or colonial ascidians especially when oscules are still evident. Rigid Thessaloniki), Javier Cristobo and Pilar Rios (IEO Gijón). common and important in height soft bottom This poster was produced with the support of the FAO-Norway the deep-sea. sponges with a high density of spicules and cyanobacterial coverage can be mistaken for coralline algae. Deep-Seas Fisheries Project (GCP/GLO/323/NOR). © FAO, 2017 - I6945EN/1/03.17 © FAO,