Manuel Ballesteros

Triterpene Glycosides from Antarctic Sea Cucumbers. 1. Structure of Liouvillosides A1, A2, A3, B1, and B2 from the Sea Cucumber Staurocucumis liouvillei: New Procedure for Separation of Highly Polar Glycoside Fractions and Taxonomic Revision

Five new triterpene glycosides, liouvillosides A1 (1), A2 (2), A3 (3), B1 (4), and B2 (5), have been isolated from the Antarctic sea cucumber Staurocucumis liouviellei along with the known liouvilloside A(6), isolated earlier from the same species, and hemoiedemosides A (7) and B (8), isolated earlier from the Patagonian sea cucumber Hemioedema spectabilis. The isolation was carried out using a new chromatographic procedure including application of ion-pair reversed-phase chromatography followed by chiral chromatography on a cyclodextrin ChiraDex column. The structures of the new glycosides were elucidated using extensive NMR spectroscopy (1H and 13C NMR spectrometry, DEPT, 1H-(1)H COSY, HMBC, HMQC, and NOESY), ESI-FTMS, and CID MS/MS, and chemical transformations. Glycosides 1-3 are disulfated tetraosides and glycosides 4 and 5 are trisulfated tetraosides. Glycosides 2 and 3 contain 3-O-methylquinovose, found for the first time as a natural monosaccharide in sea cucumber glycosides. On the basis of analyses of glycoside structures a taxonomic revision is proposed.

Triterpene glycosides from Antarctic sea cucumbers III. Structures of liouvillosides A4 and A5, two minor disulphated tetraosides containing 3-O-methylquinovose as terminal monosaccharide units from the sea cucumber Staurocucumis liouvillei (Vaney)

Two new minor triterpene glycosides, liouvillosides A4 (1) and A5 (2) have been isolated from the sea cucumber Staurocucumis liouvillei living in Antarctic and Sub-Antarctic waters. The structures of the new glycosides were elucidated using extensive nuclear magnetic resonance (NMR) spectroscopy (1H- and 13C-NMR spectroscopy, 1H–1H COSY, 1D-TOCSY, HMBC, HSQC and NOESY), ESI-MS and MALDI TOF MS. The glycosides 1 and 2 are disulphated tetraosides having very rare 3-O-methylquinovose as terminal monosaccharide.

Spatial patterns and diversity of bryozoan communities from the Southern Ocean: South Shetland Islands, Bouvet Island and Eastern Weddell Sea

In this study, we report new data on the biodiversity and the geographic and bathymetric distribution of bryozoans collected during the ANT XXI/2 cruise (November 2003 to January 2004) in the Eastern Weddell Sea and Bouvet Island, and during the Spanish Antarctic expedition ECOQUIM (January 2006) in the South Shetland Islands. Our data on distribution were analysed together with previous studies carried out in the same regions. A total of 54 species of Antarctic bryozoans (206 samples), including a new species of the genus Reteporella were found. Two species were reported for the first time from Bouvet Island, one from the Weddell Sea and one from Spiess Seamount. Fifty-five per cent of all species identified were endemic to Antarctica. In the Weddell Sea, the regions of Austasen and Kapp Norvegia exhibit the highest relative species richness, followed by the Vestkapp region. Multivariate and cluster analyses revealed small-scale spatial variability in the community structure along depth and between localities.

Biosynthetic origin and anatomical distribution of the main secondary metabolites in the nudibranch mollusc Doris verrucosa

Abstract 1. 1. The biosynthetic origin of the verrucosins, ichthyotoxic diacylglycerols of the nudibranch mollusc Doris verrucosa, has been investigated by administration of [2-14C]mevalonic acid and [U-14C]-glycerol. The poor incorporation results do not clearly establish the existence of a de novo biosynthesis. 2. 2. The comparison of the secondary metabolites in D. verrucosa specimens collected in different habitats, as well as of the secondary metabolites of its principal prey, the sponge Hymeniacidon sanguinea, suggest that verrucosins are biosynthesized de novo by the mollusc. 3. 3. A good incorporation of [2-14C]mevalonic acid into the sterols established that the mevalonate pathway is operative in D. verrucosa.

Chemical Interactions in Antarctic Marine Benthic Ecosystems

Antarctic marine ecosystems are immersed in an isolated, relatively constant environment where the organisms inhabiting their benthos are mainly sessile suspension feeders. For these reasons, physical and chemical biotic interactions play an essential role in structuring these marine benthic communities (Dayton et al., 1974; Orejas et al., 2000). These interactions may include diverse strategies to avoid predation (e.g. Iken et al., 2002), competition for space or food (e.g. Bowden et al., 2006) and avoiding fouling (e.g. Rittschof, 2001; Peters et al., 2010). For instance, in the marine benthos, one of the most extended effective strategies among sessile soft-bodied organisms is chemical defense, mediated by several bioactive natural products mostly considered secondary metabolites (e.g. Paul et al., 2011). The study of the “chemical network” (chemical ecology interactions) structuring the communities provides information about the ecology and biology of the involved species, the function and the structure of the community and, simultaneously, it may lead to the discovery of new compounds useful to humans for their pharmacological potential (e.g. Avila, 1995; Bhakuni, 1998; Munro et al., 1999; Faulkner, 2000; Lebar et al., 2007; Avila et al., 2008). In the last three decades, the study of marine chemical ecology has experienced great progress, thanks to the new technological advances for collecting and studying marine samples, and the possibility of identification of molecules with smaller amounts of compounds (e.g. Paul et al., 2006, 2011; Blunt et al., 2011).

A new tritoniid species (Mollusca: Opisthobranchia) from Bouvet Island

Tritoniid sea slugs (Mollusca, Gastropoda, Opisthobranchia) are reported for the first time from Bouvet Island. Tritonia dantarti sp. n. shows morphological and anatomical differences with regard to the two previously known tritoniids reported from Antarctica and Sub-Antarctica, Tritonia vorax (Odhner 1926) and Tritonia challengeriana Bergh, 1884. Regarding the external morphology, T. dantarti sp. n. is characterized by a very bright orange coloration in the dorsum, white dorsal crests, highly ramified dendritic gills (the largest vertically orientated and the rest laterally orientated), and a quadrangular cross section. The radula presents very long, thin lateral teeth and the jaws present mainly unicuspidate, striated denticles. The seminal receptacle is large, pear-shaped and its grey pigmentation differs from the rest of the genital system. The Antarctic species T. challengeriana was also found in waters off Bouvet Island, while the Subantarctic species T. vorax was not found.

The end of the cold Loneliness: 3D comparison between Doto antarctica and a new sympatric species of Doto (Heterobranchia: Nudibranchia)

Although several studies are devoted to determining the diversity of Antarctic heterobranch sea slugs, new species are still being discovered. Among nudibranchs, Doto antarctica Eliot, 1907 is the single species of this genus described from Antarctica hitherto, the type locality being the Ross Sea. Doto antarctica was described mainly using external features. During our Antarctic research on marine benthic invertebrates, we found D. antarctica in the Weddell Sea and Bouvet Island, suggesting a circumpolar distribution. Species affiliation is herein supported by molecular analyses using cytochrome c oxidase subunit I, 16S rRNA, and histone H3 markers. We redescribe D. antarctica using histology, micro-computed tomography (micro-CT), and 3D-reconstruction of the internal organs. Moreover, we describe a new, sympatric species, namely D. carinova Moles, Avila & Wägele n. sp., and provide an anatomical comparison between the two Antarctic Doto species. Egg masses in both species are also described here for the first time. We demonstrate that micro-CT is a useful tool for non-destructive anatomical description of valuable specimens. Furthermore, our high resolution micro-CT data reveal that the central nervous system of both Doto species possesses numerous accessory giant cells, suggested to be neurons herein. In addition, the phylogenetic tree of all Doto species sequenced to date suggests a scenario for the evolution of the reproductive system in this genus: bursa copulatrix seems to have been reduced and the acquisition of a distal connection of the oviduct to the nidamental glands is a synapomorphy of the Antarctic Doto species. Overall, the combination of thorough morphological and anatomical description and molecular analyses provides a comprehensive means to characterize and delineate species, thus suggesting evolutionary scenarios.

Breaking out of the comfort zone: El Niño-Southern Oscillation as a driver of trophic flows in a benthic consumer of the Humboldt Current ecosystem

The trophic flow of a species is considered a characteristic trait reflecting its trophic position and function in the ecosystem and its interaction with the environment. However, climate patterns are changing and we ignore how patterns of trophic flow are being affected. In the Humboldt Current ecosystem, arguably one of the most productive marine systems, El Niño-Southern Oscillation is the main source of interannual and longer-term variability. To assess the effect of this variability on trophic flow we built a 16-year series of mass-specific somatic production rate (P/B) of the Peruvian scallop (Argopecten purpuratus), a species belonging to a former tropical fauna that thrived in this cold ecosystem. A strong increase of the P/B ratio of this species was observed during nutrient-poor, warmer water conditions typical of El Niño, owing to the massive recruitment of fast-growing juvenile scallops. Trophic ecology theory predicts that when primary production is nutrient limited, the trophic flow of organisms occupying low trophic levels should be constrained (bottom-up control). For former tropical fauna thriving in cold, productive upwelling coastal zones, a short time of low food conditions but warm waters during El Niño could be sufficient to waken their ancestral biological features and display massive proliferations.

First record of the gastropod Philinopsis wildpretii (Ortea, Bacallado and Moro, 2003) (Cephalaspidea, Aglajidae) in the Iberian Peninsula

The cephalaspidean gastropod Philinopsis wildpretii (Ortea, Bacallado and Moro, 2003) was first described for the Canary island of Gran Canaria (Ortea et al. 2003). Initially included in the genus Melanochlamys, it was later changed by the same authors to the genus Spinoaglaja (Ortea et al. 2013) based on external and shell morphology. Ornelas-Gatdula and Valdés (2012), using molecular and morphological data, consider Spinoaglaja to be a synonym of Philinopsis, as is also suggested by Camacho-García et al. (2014) in their phylogeny of the Aglajidae. WoRMS (accessed April 25, 2016) accepts this species under the name Melanochlamys wildpretii, and in the CLEMAMdatabase (accessed April 25, 2016) it is considered synonymous with Spinoaglaja aeci. According to the latest published molecular analysis, we consider this species as belonging to the genus Philinopsis until the status of Spinoaglaja is completely resolved in a future study. Since its description, only a few specimens have been observed, all in the Mediterranean Sea: only shells in the Greek islands (Manousis et al. 2012) and in the island of Malta (Romani and Pagli 2015), five living specimens in Sardinia (Trainito and Doneddu 2014), one in the French Mediterranean (Horst and Juan 2014) and one in Porto Cesareo (Lecce, Italy) (12/11/2015, F. Vitale, SalentoSommerso). In this paper we present the first record of its presence in the Iberian Peninsula waters, along the Catalan coast (NE Spain), one animal being observed in each of the following locations (Fig. 1): Tossa deMar (M. Ballesteros, 12/ 13/2011), Sa Tuna (Begur) (X. Salvador, 12/05/2013), Morro del Vedell (Palamós) (E. Madrenas, 10/03/2014) and Cap de Creus (E. Madrenas, 10/31/2015). These observations suggest that the species has a wider distribution than formerly known, and given that all records since its description have been in the Mediterranean Sea, it should be considered as a kind of Atlanto-Mediterranean species or, as some authors have found (Ornelas-Gatdula and Valdés 2012), the Canarian and Mediterranean specimens could correspond to two different sympatric cryptic species with minute external differences. According to the original description, the animals from the Canary Islands have digging habits and live in mud or sand bottoms with half-buried stones covered with turf of algae, between 4 and 15 m deep; they move swiftly on the sediment and are able to bury themselves within seconds. Mediterranean specimens were found in shallow sandy bottoms near rocks where the algae Acetabularia acetabulum and Liagora viscida were growing (Horst et al. 2014), and also on leaves and rhizomes of Posidonia oceanica and Cymodocea nodosa meadows with Caulerpa prolifera and C. cylindracea (Trainito et al. 2014). The specimens observed in the Catalan coast of the Iberian Peninsula have been found among rhizomes of Posidonia oceanica and masses of photophilic algae.. Communicated by V. Urgorri