Structural Characterization and Profiles of Saponins from Two Algerian Sea Cucumbers.

peer reviewedSea cucumbers are benthic marine invertebrate members of the phylum Echinodermata. Due to the absence of a rigid skeleton, these species have developed chemical defenses based on the production of saponins (triterpene glycosides). These secondary metabolites are bioactive molecules with a broad biological, ecological, and pharmaceutical spectrum. However, the saponin profiles of several species of sea cucumbers are not known yet. The present study aims to highlight the mixture of saponins in two sea cucumber species from the Algerian coast, namely Holothuria (Holothuria) algeriensis, which has been recently described in central and western Algerian waters, and Holothuria (Roweothuria) arguinensis, originating from the Atlantic Ocean and reported in Algeria for the first time in 2014. Saponin extracts from three individuals of H. (H.) algeriensis and two individuals of H. (R.) arguinensis were analyzed using mass spectrometry, i.e., Matrix-assisted Laser Desorption/Ionization mass spectrometry (MALDI-MS), MALDI-High Resolution MS (MALDI-HRMS), Liquid Chromatography MS (LC-MS) and tandem MS (LC-MS/MS). These analyses allow us to detect 11 and 18 elemental compositions for H. (H.) algeriensis and H. (R.) arguinensis, respectively, each presenting several isomers. In total, 13 new saponin structures are proposed, of which four are common between the two species, six are specific to H. (H.) algeriensis and three to H. (R.) arguinensis. The saponin profiles of the two species were compared to those of other species of the same genus existing on the Algerian coast and the results showed that they share non-sulfated saponins with Holothuria (Panningothuria) forskali and Holothuria (Platyperona) sanctori and sulfated saponins with Holothuria (Holothuria) tubulosa and Holothuria (Roweothuria) poli

Sur la présence de Cymbula safiana (Gastropoda : Patellidae) au niveau de la côte algérienne (Méditerranée sud-ouest) : structure des populations et nouvelles stations de signalisation

Cymbula safiana (Lamarck, 1819) is an endangered gastropod species in the Mediterranean. In Algeria, few studies have been devoted to this species. The aim of the present work is to study the population structure of C. safiana considering size and density in six stations of the Algerian coast. Through this study, we recorded for the first time C. safiana in four stations of the Algerian coast (Port de Salamandre, Port de Aïn Taya, Figuier Plage and Collo) where this species was never reported before. Our results showed the existence of a size-class of young individuals [ 3-4cm] at Kharouba, Figuier Plage and Collo stations representing a massive recruitment event. The largest measured shell was found at Kharouba station (8.5cm). Habitats with smooth, homogeneous substratum appeared to host the most important densities of C. Safiana : Port de Salamandre (5.2ind/ m) and Figuier Plage (2.1ind/ m). Cymbula safiana seems to be well established on the Algerian coast, as shown by its clear progression and extension to the eastern part of Algeria. However, the intense urbanization of coastal areas and the lack of legislation on its protection status are serious threats that could challenge this situation.Cymbula safiana (Lamarck, 1819) est une espèce de gastéropode menacée de disparition en Méditerranée. En Algérie, peu d’études lui ont été consacrées. Le présent travail a pour objectif d’étudier la structure en taille et en densité des populations de C. safiana dans six stations de la côte algérienne. À travers cette étude, nous avons pu signaler pour la première fois C. safiana dans quatre stations de la côte algérienne (port de Salamandre, port de Aïn Taya, Figuier Plage et Collo). Nos résultats ont montré l’existence d’une classe de taille de jeunes individus [ 3-4 cm] dans les stations de Kharouba, Figuier Plage et Collo représentant un évènement de recrutement massif. La plus grosse taille de coquille mesurée dans notre étude se trouvait à Kharouba (8,5 cm). Les habitats à substrats lisses et homogènes paraissent abriter les plus importantes densités d’individus de C. safiana : par exemple, 5,2 ind/ m au port de Salamandre et 2,1 ind/ m à Figuier Plage. Cymbula safiana semble être bien installée sur les côtes algériennes, comme en témoigne son aire de distribution en nette progression vers l’est de l’Algérie. Cependant, l’urbanisation intense des zones côtières et l’absence de législation relative à son statut de protection pourraient remettre en cause cette situation.Bouzaza Zoheir, Mezali Karim. Sur la présence de Cymbula safiana (Gastropoda : Patellidae) au niveau de la côte algérienne (Méditerranée sud-ouest) : structure des populations et nouvelles stations de signalisation. In: Ecologia mediterranea, tome 45 n°1, 2019. pp. 5-13

Comparison of isotopic niches of four sea cucumbers species (Holothuroidea: Echinodermata) inhabiting two seagrass meadows in the southwestern Mediterranean Sea (Mostaganem, Algeria)

Among the fauna inhabiting the Posidonia oceanica seagrass meadow, holothurians are particularly abundant and provide essential ecological roles, including organic matter recycling within seagrass sediments. This study aimed to investigate the trophic niche of four holothurians of the order Holothuriida [Holothuria poli (Delle Chiaje, 1824), Holothuria tubulosa (Gmelin, 1791), Holothuria sanctori (Delle Chiaje, 1823) and Holothuria forskali (Delle Chiaje, 1823)] inhabiting P. oceanica meadows, through the measurement of nitrogen and carbon stable isotope ratios. Two shallow and contrasting sites of the littoral region of Mostaganem (North West Algeria) were chosen. The first site, located in Stidia, is weakly impacted by human activities. The second site, located in Salamandre, is highly impacted by human activities (industries, harbor facilities). High values of δ15N in holothurians and their food sources were observed at both sites. The δ13C values showed a lower contribution from detritic Posidonia than in other areas. This could be a consequence of P. oceanica bed degradation in the studied area. The stable isotope approach did not reveal dietary differences between species, and the four holothurians species exhibited significant isotopic niche overlap. However, niche sizes differed between species showing more variable individual trophic diversity in some species (H. tubulosa and H. sanctori in Salamandre; H. forskali in Stidia). If niche segregation does occur, it is not in terms of general resource use. More likely, it would be the abundance of food sources, the different life habits and their micro-habitats that may explain their co-existence in the P. oceanica seagrass meadow.</jats:p

On the taxonomic status of Holothuria (Holothuria) tubulosa (s.s.) from the Algerian coast with the description of a new Mediterranean species, Holothuria (Holothuria) algeriensis n. sp. (Echinodermata: Holothuroidea: Holothuriidae)

In this study we redescribe the taxonomy of some holothuriid species collected from different localities of the Algerian coastal waters. Morphological (anatomical and endoskeletal) and previous molecular studies show the presence of two distinct morphotypes of Holothuria (Holothuria) tubulosa “A” &amp; “B”. Morphotype “A” corresponds to the classical Holothuria (Holothuria) tubulosa Gmelin 1791, described by Koehler (1921) and hereafter referred to as H. (H.) tubulosa (s.s.), while morphotype “B”, we believe, represents a new species, herein named H. (Holothuria) algeriensis n. sp. with characteristics significantly different from those of Holothuria (H.) tubulosa (s.s.). Both morphology and statistical analysis (Linear Discriminant Analysis) confirm significant differences between these two morphotypes. To visualize these differences, measurements made on ossicles of Holothuria (H.) tubulosa (s.s.) and Holothuria (H.) algeriensis n. sp. were compared with other species present in our collections, including the north-eastern Atlantic and Mediterranean Holothuria (Roweothuria) arguinensis Koehler &amp; Vaney, 1906, recently recorded from Algerian waters, the Mediterranean Holothuria (Roweothuria) poli Delle Chiaje, 1824 and Holothuria (Holothuria) stellati Delle Chiaje, 1824. We conclude that the two morphotypes of H. (H.) tubulosa are significantly different to warrant the recognition of a new species, H. (H.) algeriensis n. sp. and the linear discriminant analysis (LDA) of the five species demonstrate this. </jats:p

KARIM MEZALI, AHMED S. THANDAR & IHCENE KHODJA (2020) Paraleptopentacta, a new Mediterranean and north-west Atlantic sea cucumber genus, with the first record of P. tergestina n comb. (Echinodermata: Dendrochirotida: Cucumariidae) from the north-western Algerian coast Zootaxa, 4860: 199-210.

Mezali, Karim, Thandar, Ahmed S., Khodja, Ihcene (2020): KARIM MEZALI, AHMED S. THANDAR & IHCENE KHODJA (2020) Paraleptopentacta, a new Mediterranean and north-west Atlantic sea cucumber genus, with the first record of P. tergestina n comb. (Echinodermata: Dendrochirotida: Cucumariidae) from the north-western Algerian coast Zootaxa, 4860: 199-210. Zootaxa 4894 (4): 600-600, DOI: https://doi.org/10.11646/zootaxa.4894.4.

Holothuria (Roweothuria) arguinensis Koehler & Vaney 1906

Holothuria (Roweothuria) arguinensis Koehler & Vaney, 1906 Figure 4B, Table 4 Material examined. CMNI 2021 – 0194, Salamandre, Algeria, 35°55.221’N, 0°03.470’E, 2 m, November 2014, 1 spec. LPVCMRMS2020.207, Ouillis, Algeria, 36°7.436’N, 0°15.219’E, 5 m, June 2020, 2 specs. Description. Semi-cylindrical body with dorsal surface (Figure 4 Ba) arched, dark brown in color; ventral surface (Figure 4 Bb) sole-like, light brown in color. Several large protuberances in two double rows on the dorsal surface; in addition, dorsal and ventral surfaces separated by several arched protuberances. Anus terminal. Mouth surrounded by 20 tentacles. Cuvierian tubules absent. Collar around mouth thick (about 4.60 mm). Calcareous ring with broad, squarish, radial plates with a shallow anterior notch, almost flat anterior portions and slightly concave posterior margin (Table 4). Ossicles. Body wall tables (Figure 4 Bc) sometimes with a rectangular disc, spire of straight to slightly arched pillars, parallel to each other. Buttons often shaped in the figure of “8” (Figure 4 Bd) with rough, irregular and prickly margins but with a smooth surface with unequally-sized perforations. Pedicels also with numerous elongated perforated plates (Figure 4 Be) and other rare enlarged plates. Rods of tentacles larger and more complex with an enlarged, branched and perforated middle region, arched (Figure 4 Bf) or straight (Figure 4 Bg).Published as part of Mezali, Karim, Thandar, Ahmed S. & Khodja, Ihcene, 2021, On the taxonomic status of Holothuria (Holothuria) tubulosa (s. s.) from the Algerian coast with the description of a new Mediterranean species, Holothuria (Holothuria) algeriensis n. sp. (Echinodermata: Holothuroidea: Holothuriidae), pp. 89-106 in Zootaxa 4981 (1) on page 96, DOI: 10.11646/zootaxa.4981.1.4, http://zenodo.org/record/489762