TY - GEN

T1 - Overview on the Homoscleromorpha sponges diversity in the Mediterranean.

AU - Ereskovsky, Alexander V.

AU - Ivanisevic, Julijana

AU - Pérez, Thierry

PY - 2009

Y1 - 2009

N2 - Sponges are often dominant in marine benthic communities, especially on Mediterranean hard substrates. TheHomoscleromorpha group is a poorly known sponge clade, represented by a single family, the Plakinidae, with anunresolved phylogenetic position at the basis of the Metazoan tree. For some of the representatives of this group, theabsence of skeleton, main morphological character for sponge taxonomy, explains also the very complicated history ofspecies statut. At present time, 77 species are listed in the World Data Base, with 22 valid species in the Mediterraneanand several representatives remaining to be described. All the genera of the family are represented in theMediterranean: one species from genus Corticium, one species of Pseudocorticium, one species of Placinolopha, onePlakortis, ten species of Plakina and 8 Oscarella species. Most of these sponges only grow sparsely in the Mediterraneanwith distributions often limited to dark submarine caves. The exceptions are Corticium candelabrum and several speciesof the genus Oscarella, who seem to grow only on coralligenous substratum. In some places, Oscarella sp. can bepredominant and constitute specific facies. Therefore, they appear as strong competitors for space, overgrowing massivesponges, sea fans and bryozoans. This is especially the case of a new species which seems to be highly dynamic. Thisstrong out-competing ability may be particularly due to an efficient secondary metabolism and the biochemical defense itconfers. This hypothesis is also supported by the absence of well-known predator or epibiotic organisms.

AB - Sponges are often dominant in marine benthic communities, especially on Mediterranean hard substrates. TheHomoscleromorpha group is a poorly known sponge clade, represented by a single family, the Plakinidae, with anunresolved phylogenetic position at the basis of the Metazoan tree. For some of the representatives of this group, theabsence of skeleton, main morphological character for sponge taxonomy, explains also the very complicated history ofspecies statut. At present time, 77 species are listed in the World Data Base, with 22 valid species in the Mediterraneanand several representatives remaining to be described. All the genera of the family are represented in theMediterranean: one species from genus Corticium, one species of Pseudocorticium, one species of Placinolopha, onePlakortis, ten species of Plakina and 8 Oscarella species. Most of these sponges only grow sparsely in the Mediterraneanwith distributions often limited to dark submarine caves. The exceptions are Corticium candelabrum and several speciesof the genus Oscarella, who seem to grow only on coralligenous substratum. In some places, Oscarella sp. can bepredominant and constitute specific facies. Therefore, they appear as strong competitors for space, overgrowing massivesponges, sea fans and bryozoans. This is especially the case of a new species which seems to be highly dynamic. Thisstrong out-competing ability may be particularly due to an efficient secondary metabolism and the biochemical defense itconfers. This hypothesis is also supported by the absence of well-known predator or epibiotic organisms.

KW - Homoscleromorpha

KW - Oscarella

KW - Mediterranean

KW - distribution

KW - ecology

M3 - Conference contribution

SP - 88

EP - 94

BT - Proceedings First Mediterranean Symposium on the Coralligenous and other calcareous bio-concretions of the Mediterranean Sea. Tabarka, Tunisie

CY - Tunis

T2 - SYMPOSIUM ON THE CONSERVATION OF THE CORALLIGENOUS AND OTHER CALCAREOUS BIO-CONCRETIONS

Y2 - 15 January 2009 through 16 January 2009

ER -