Luis Sánchez-Tocino

Contribution to the knowledge of the genus Loxosomella (Entoprocta) from the Spanish Mediterranean Sea, with the description of a new species, Loxosomella ameliae sp. nov.

Abstract A study of loxosomatidae inhabiting demosponges of the genera Ircinia and Sarcotragus in the Iberian Mediterranean Sea has shown the occurrence of two species. One of them, identified as Loxosomella pes, is recorded for the first time from Spanish waters and some biometric data of the studied population are provided. The other species is new and is here described as Loxosomella ameliae sp. nov. The existence of a wide field of conspicuous gland cells and some features of the foot and calyx characterize the new species and distinguish it from other cogeneric species. With this new species, a total of five species of Loxosomella reported from sponges are known from the Mediterranean Sea.

Amphipod community associated with invertebrate hosts in a Mediterranean marine cave

The present study explored the amphipod communities associated with the dominant host invertebrates inhabiting a marine cave of South Spain in order to describe their species composition and distribution patterns. Although they play a key role in the structure of mobile epifaunal communities inhabiting most rocky reef ecosystems, this component of marine caves communities has often been overlooked. Colonies of six sessile species were collected: Astroides calycularis, Parazoanthus axinellae, Pentapora fascialis, Aldeonella calveti, Filograna implexa, and Ircinia fasciculata. In each sample the mobile epifaunal community (mainly focusing on the amphipod group) was characterized, with Arthropoda and Amphipoda being the dominant phylum and order, respectively. Among amphipods, the gammarid Lembos websteri and the caprellids Phtisica marina and Pseudoprotella phasma were the most abundant species. The endangered coral Astroides calycularis showed the most distinctive amphipod community and multivariate analysis highlighted the existence of significant differences in the amphipod assemblages among invertebrate hosts in the cave. However, no host-specific species were found. Benthic hosts inside the cave are mainly used as a refuge by amphipods and all the sessile species studied seem to play an equivalent facilitation role. To what extent changes in the composition of sessile species may affect other associated species was also discussed.

Ontogenetic changes in the spicule formation and their possible role in chromodorid opisthobranchs (Mollusca, Chromodorididae)

Abstract Many dorid nudibranchs have calcareous spicules in their integument. These structures were lost during their evolution in some dorid lineages, as usually stated for most genera of the family Chromodorididae. Nevertheless, in this article, the presence of calcareous spicules is reported upon for the first time in 12 southern European species belonging to the genera Felimare and Felimida: Felimare villafranca, Felimare picta, Felimare orsinii, Felimare fontandraui, Felimare bilineata, Felimare cantabrica, Felimare tricolor, Felimida luteorosea, Felimida purpurea, Felimida krohni, Felimida luteopunctata and Felimida britoi. The spicules are arranged in the notum, lateral region of the body, rhinophores, gills and feet, and their morphology is very variable, even in the same species. Moreover, changes in size, shape and arrangement between juvenile and adult stages can be observed. Potential biological roles of these structures are discussed.