Sponges of Western Mediterranean seamounts: new genera, new species and new records

Abstract

Background The seamounts Ses Olives (SO), Ausias March (AM) and Emile Baudot (EB) at the Mallorca Channel (Balearic Islands, western Mediterranean), are poorly explored areas containing rich and singular sponge communities. Previous works have shown a large heterogeneity of habitats, including rhodolith beds, rocky, gravel and sandy bottoms and steeped slopes. This diversity of habitats provides a great opportunity for improving the knowledge of the sponges from Mediterranean seamounts. Methods Sponges were collected during several surveys carried out by the Balearic Center of the Spanish Institute of Oceanography at the Mallorca Channel seamounts. Samples were obtained using a beam-trawl, rock dredge and remote operated vehicle. Additional samples were obtained from fishing grounds of the Balearic Islands continental shelf, using the sampling device GOC-73. Sponges were identified through the analysis of morphological and molecular characters. Results A total of 60 specimens were analyzed, from which we identified a total of 19 species. Three species and one genus are new to science: Foraminospongia balearica gen. nov. sp. nov., Foraminospongia minuta gen. nov. sp. nov. and Paratimea massutii sp. nov. Heteroxya cf. beauforti represents the first record of the genus Heteroxya in the Mediterranean Sea. Additionally, this is the second report of Axinella spatula and Haliclona (Soestella) fimbriata since their description. Moreover, the species Petrosia (Petrosia) raphida, Calyx cf. tufa and Lanuginella pupa are reported for the first time in the Mediterranean Sea. Petrosia (Strongylophora) vansoesti is reported here for the first time in the western Mediterranean Sea. Haliclona (S.) fimbriata is reported here for the first time in the north-western Mediterranean Sea. Hemiasterella elongata is reported here for the second time in the Mediterranean Sea. The species Melonanchora emphysema, Rhabdobaris implicata, Polymastia polytylota, Dragmatella aberrans, Phakellia ventilabrum and Pseudotrachya hystrix are reported for first time off Balearic Islands. Following the Sponge Barcoding project goals, we have sequenced the Cytochrome Oxidase subunit I (COI) and the 28S ribosomal fragment (C1–D2 domains) for Foraminospongia balearica sp. nov., Foraminospongia minuta sp. nov., H. cf. beauforti and C. cf. tufa, and the COI for Paratimea massuti sp. nov. We also provide a phylogenetic analysis to discern the systematic location of Foraminospongia gen. nov., which, in accordance to skeletal complement, is placed in the Hymerhabdiidae family. A brief biogeographical discussion is provided for all these species, with emphasis on the sponge singularity of SO, AM and the EB seamounts and the implications for their future protection.

Improving Scientific Knowledge of Mallorca Channel Seamounts (Western Mediterranean) within the Framework of Natura 2000 Network

“…Our results agree with Galil and Zibrowius (1998) [104] who suggested that Mediterranean seamounts can be considered as isolated refuges for relict populations of species that have disappeared from a previously larger distribution range [70] and that also provide an excellent habitat for rich communities of filter-feeding animals such as sponges [69]. This fact, together with the presence of species and habitats of special interest for their protection, justify the inclusion of the seamounts of the Mallorca Channel within the Natura 2000 network.…”

“…Some of the identified species up to date have been new to science and new records in the study area or even in the Mediterranean. This is the case of the discovery of the new genus of sponge Foraminospongia, whose type species F. balearica is one of the most abundant sponges at the AM and EB summits and the other two new sponge species F. minuta and Paratimea masuttii [69]. Moreover, new geographical records have been published for another 16 sponges [69] and one ophiuroid [70], with this last species also abundant in the study area.…”

“…This is the case of the discovery of the new genus of sponge Foraminospongia, whose type species F. balearica is one of the most abundant sponges at the AM and EB summits and the other two new sponge species F. minuta and Paratimea masuttii [69]. Moreover, new geographical records have been published for another 16 sponges [69] and one ophiuroid [70], with this last species also abundant in the study area. Some species have been found at depths where they had not been previously recorded, which was the case of two little known decapod crustaceans: the alpheids Alpheus platydactylus and Alpheus cf.…”

A new species of the genus Ophiomyxa (Echinodermata: Ophiuroidea: Ophiomyxidae) from the Mallorca Channel seamounts in the western Mediterranean

“…recent surveys carried out in the Mallorca Channel seamounts, including Ausias March, Ses Olives and Emile Baudot seamounts (Massutí et al 2022), have substantially improved our knowledge of Mediterranean invertebrates. This improvement has been particularly important for sponges, with the description, so far, of seven new species (Díaz et al 2021;2023a), but also echinoderms, with the report of the first Mediterranean record of a brittle star of the family Ophiohelidae Perrier, 1873, Ophiomyces grandis lyman, 1879, which showed high abundances in these seamounts despite its absence from insular coasts (Ordines et al 2019).…”

New Deep-Sea Molluscan Records from Mallorca Channel Seamounts (North-Western Mediterranean)

“…Recent studies have already highlighted the ecological importance of these seamounts, where up to 547 taxa and 29 categories of benthic habitats have been found [14]. Biodiversity studies on unexplored areas, such as seamounts, lead, in most cases, to the discovery of new species for science [15], to new species records [16] or to an increase in species distribution knowledge (geographical and/or bathymetric) [17].…”