RESUMEN

A new species belonging to the ophiuroid genus Ophiomyxa is described from the Mallorca Channel seamount, in the western Mediterranean Sea. It can be distinguished from other Ophiomyxa species by the lack of interradial marginal plates, three arm spines, the presence of two thin, transparent and completely perforated dorsal arm plates on each arm segment, the separate heptagonal ventral arm plates, the disk integument full of transparent rounded scales with scattered perforated ossicles, and a characteristic coloration of the disk, which in the living specimen is brown with abundant scattered bright white spots. Molecular analyses based on cytochrome c Oxidase subunit I (DNA barcode) clearly support the assignment of the new species to Ophiomyxa. This discovery highlights the importance of the Mallorca Channel seamounts for the Mediterranean biodiversity conservation, as they seem to provide a suitable habitat for several invertebrate species, including recent descriptions of species and new Mediterranean records, which apparently have not established permanent populations along the closest continental margin.

Asunto(s)

RESUMEN

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.

RESUMEN

Many deep-water fish populations, being K-selected species, have little resilience to overexploitation and may be at serious risk of depletion as a consequence. Sea warming represents an additional threat. In this study, the condition, or health, of several populations of common ling (Molva molva), blue ling (Molva dypterygia) and Mediterranean or Spanish ling (Molva macrophthalma) inhabiting different areas in the North Atlantic and the Mediterranean was evaluated, to shed light on the challenges these deep-water species are facing in the context of fishing activity and a warming climate. The data on the condition of Molva populations which are analysed here have been complemented with data on abundance and, for the southernmost species (Mediterranean ling), with two other health indicators (parasitism and hepato-somatic index). Despite some exceptions (e.g., common ling in Icelandic waters), this study shows that the condition of many populations of Molva species in the northeastern Atlantic and the Mediterranean Sea has worsened, a trend which, in recent decades, has usually been found to be accompanied by a decline in their abundance. In addition, the poor health status of most populations of common ling, blue ling and Mediterranean ling considered in this analysis points to a lower sustainability of these populations in the future. Overall, the health status and abundance of Molva populations in the northeastern Atlantic and the Mediterranean suggest that only some populations located in the North Atlantic may be able to rebuild, whereas the populations in southern North Atlantic and the Mediterranean, which are probably most at risk from sea warming, are facing serious difficulties in doing so. In the context of fisheries and global warming, this study's results strongly indicate that management bodies need to consider the health status of many of the populations of Molva species, particularly in southern European waters, before implementing their decisions.

Asunto(s)

RESUMEN

Chondrichthyans are a vulnerable group that has been overexploited for almost half a century in the Mediterranean. Since in this area most chondrichthyans are rarely incorporated into international statistics, the impact of fishing on their populations is difficult to assess. Here, we evaluate temporal trends in order to understand the recent history of chondrichthyans in the western Mediterranean. Fishery-independent data were obtained from scientific surveys carried out from 1994 to 2015 in three geographical sub-areas. Our results reflect fairly stable populations in terms of diversity, with some increase in density and standardized biomass of some species dwelling on the continental shelf, and even for some species dwelling on the slope. In contrast, decreasing trends were observed in some deep-water species. This can be explained by the reduction of the trawling effort on the continental shelf over the last few decades, and the shift of the fleet towards deep waters, along with the greater resilience displayed by some species. Furthermore, a decreasing trend in maturity of Scyliorhinus canicula was detected, suggesting an evolutionary response to overfishing. These results improve scientific knowledge for developing true adaptive management in the Mediterranean that will implement measures to strengthen or initiate the recovery of chondrichthyans.

Asunto(s)

RESUMEN

A new genus and species of goby, Gymnesigobius medits sp. nov., is described from the western Mediterranean slope bottoms at the Balearic Islands. The new goby belongs to the Gobius-lineage (Gobiinae). Examination of the single known specimen exhibits a unique combination of morphological characters which could not be fitted to any known genus. Gymnesigobius gen. nov. is morphologically distinguished from all other genera in the Gobius-lineage by the following combination of characters: chin without fold or barbels; mouth terminal with anterior tip above horizontal level of lower eye edge; predorsal area and first dorsal fin base naked; pelvic fin anterior membrane well developed; head with anterior oculoscapular and preopercular canals, posterior oculoscapular canal absent; pores of head canals enlarged, e.g. pores α and ρ larger or of about the same size as interspaces to pore ß; six transverse suborbital rows of sensory papillae, four continuous suborbital rows in front of row b, fifth row divided in three parts but in front of row b, sixth row just as superior part above row b and below pore α; longitudinal suborbital row b barely reaching forward to the vertical from posterior edge of eye. A full description of the new genus and species is provided. The new species, collected at a depth of between 344 and 364 m (mean depth of 354 m), is one of very few gobiid species found at bathyal depths.

Asunto(s)

RESUMEN

A new goby species, Lebetus patzneri sp. nov. (Teleostei: Gobiidae) is described based on two preserved and two photographed specimens collected from two circalittoral bottom locations off the Balearic Islands, western Mediterranean. It differs from the one or both other Lebetus species by each of following characters: P 15-16; D2 segmented fin rays 7-8; snout slightly larger than eye diameter; eyes small, 23.3-25.5% of head length; body height low, body depth at pelvic fin 14.9-16.4%; lips thick, giving mouth a broad, almost rectangular shape in dorsal and lateral view; minute black "pepper" spots on predorsal area, dorsum, flanks and caudal peduncle, visible in fresh and preserved specimens; the most of the caudal peduncle similarly colored as the lateral area below D2, reddish or brown. We further report first records of Lebetus guilleti (Le Danois, 1913) from Norway and the Balearic Islands, and observations of its conspicuous courtship behavior ("D1 waving"), and coloration including the first description of its red fluorescence pattern.

Asunto(s)

RESUMEN

A new gobiid species, Buenia lombartei sp. nov. (Teleostei: Gobiidae) is described from the continental slope off the Balearic Islands, western Mediterranean. The Atlantic species Buenia jeffreysii (Günther, 1867) is redescribed and the first record of Buenia affinis Iljin, 1930 is reported for the islands. A key for the species of genus Buenia is provided. The new species can be distinguished from congeneric species by morphological characters: anterior oculoscapular canal semi-closed with pores σ, λ, κ, α, ρ and additional pores and open furrows; suborbital row c of 6 papillae; anal fin I/7-I/8; scales in lateral series 25-27; scales in transverse series 6; pectoral fin rays 18; the second spine of the first dorsal fin longest, backwards reaching to middle second dorsal fin in males when folded down; pelvic fin anterior membrane reduced to less than one sixth of spinous ray in midline depth; tongue well developed and bilobed and several morphometric characters. The new species is also characterized by its reduced colouration and unique depth range and occurrence on upper slope muddy bottoms. Contrary to this, only a small number of gobiid species in the Mediterranean reach beyond the circalittoral to the deep shelf, and just a few have records below the shelf break. Phylogenetic analysis of their mitochondrial COI sequence grouped the two specimens within the same clade as B. jeffreysii, but one apomorphic transversion diagnoses the B. lombartei subclade. A hypothesis about rapid speciation of B. lombartei as well as alternative hypotheses are discussed. During the Last Glacial Maximum, boreal fish species such as cold-water adapted gadids, now restricted to northwestern Europe, entered the Mediterranean. This may have also been the case of the boreal population of B. jeffreysii. At the end of the glacial period, increasingly warming Mediterranean waters might restricted B. jeffreysii to deeper coldwater mud habitats of the upper slope, where it finally adapted to bathyal conditions.

Asunto(s)

RESUMEN

A new goby species, Speleogobius llorisi sp. nov. (Teleostei: Gobiidae) is described from the circalittoral sea bed at 46-69 m depth off the Balearic Islands, western Mediterranean. Six specimens, four females and two males, of the new species were collected from beam trawl samples carried out on the red algae beds off the south west coast of Mallorca Island. Among others, the main traits that differentiate the new species from the only congeneric species, S. trigloides, are the presence of preopercular head canal with pores γ, δ, ε vs. preopercular head canal absent; a longer snout, equal or longer than eye vs. shorter than eye; lower lip ending anteriorly slightly in front of upper lip vs. upper lip slightly protruding lower lip; scales in lateral series 28 or 29 vs. 26; scales in transverse series 6 vs.7-8. It also differs from S. trigloides in some non-overlapping morphometrics and in coloration. All individuals of the new species were collected from Peyssonnelia beds, beds of red algae dominated by species of the family Peyssonneliaceae. The generic diagnosis of Speleogobius is revised.

Asunto(s)