UNDISCLOSED BRYODIVERSITY OF SUBMARINE CAVES OF THE AEGEAN SEA (EASTERN MEDITERRANEAN)

Bryozoan diversity from the eastern Mediterranean basin is still poorly known, especially in dark cave and deep-water habitats. Examination of samples collected from two submarine caves in Lesvos Island, Aegean Sea, revealed 74 bryozoan taxa. Most taxa (67) occurred with living and dead colonies, whereas 7 were exclusively recorded with dead colonies. Cheilostomes (59 species) outnumbered cyclostomes (14 species) and ctenostomes (1 species). Unilaminarmultilaminar encrusters prevailed; runners, spots and erect colonies were subordinate to rare. Most taxa, but 6, were already known from present-day Mediterranean. These are Palmiskenea sp. 1, Schizomavella sp. 1, Fenestrulina sp. 1, Rhynchozoon sp. 1, Setosella sp. 1, and Onychocellidae sp. 1. The last two taxa are new species, whose description is under way. The former four taxa could be either new or non-indigenous species. Assessments about their status, however, require comparison with several species distributed worldwide. Indeed, except for the genera Palmiskenea (known with 7 species, 2 from the Mediterranean), Fenestrulina, Schizomavella, and Rhynchozoon, are very rich in species in the world ocean (70, 71 and 88 species, respectively) and in the Mediterranean Sea (4, 22, and 6, respectively). To date, only one species of the above genera, R. larreyi, has been recorded as non-indigenous in the eastern Mediterranean Sea (Lebanon). The finding of 6 new taxa in two neighbouring sites supports that a considerable number of species await to be discovered from understudied sectors and habitats of the Mediterranean Sea, and especially from dark habitats. Knowledge of this diversity is crucial for monitoring and conservation initiatives.