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Background: The rhodymenialean red algal species Rhodymenia holmesii was collected in the lower intertidal zones from Dalya and Al-Hoceima (Northern Morocco, Mediterranean Sea). This represents the first record and description in the Mediterranean Sea. Results: Moroccan materiel was studied in detail and compared with other closely related species. Descriptions of the morphological features reveal thalli with flaccid blades, 8 cm long, regularly dichotomously branched and attached with stoloniferous holdfast. Anatomically, cortical region composed of 2-3 cell layers and medulla composed of 3-5 cell layers. Conclusions: This finding indicates that the biodiversity of the related sites is probably richer than generally thought, and other phycological studies will increase the known algal biodiversity of the region.

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The occurrence in Morocco of three species of red algae new to the Mediterranean Sea is reported:

The Mediterranean basin is a marine biodiversity hot spot. Despite this, the macroalgal diversity of the Mediterranean Sea is still not fully known, especially in the Mediterranean Marine Protected Areas (MPAs) including, Al-Hoceima National Park of Morocco (PNAH). This paper provides the first comprehensive checklist of the seaweeds of PNAH, based chiefly on our own original collections, and complimented by literature records. Using present-day taxonomy, the total number of taxa at both specific and infraspecific levels currently accepted is 306 taxa with 207 Rhodophyta (39 families), 51 Ochrophyta (13 families) and 48 Chlorophyta (12 families). Ninety five of these species were not found in our samples, 93 were new to the PNAH, and the taxonomic identity of 26 taxa was amended. From the totality of taxa, ten species were reported for the first time from Morocco: 9 Rhodophyta and one green alga. Furthermore, 12 others species (10 red, 1 brown and 1 green alga) are new records for the Mediterranean coast of Morocco. Besides this, confirmed records are mentioned for 20 species, whether in Africa, in Morocco or in the Moroccan Mediterranean coast. This accessible checklist to the international community could serve as an infrastructure for future algal investigations of the taxa in this Specially Protected Area of Mediterranean Importance.

Carpodesmia tamariscifolia is a brown alga rich in (poly)phenols with important cytotoxic and antioxidant effects. However, the relationship between its chemical composition and its effects is unknown. The aim of this study is to identify the potential compounds and mechanisms responsible for its main effects. The alga was extracted consecutively with hexane, dichloromethane and methanol and further fractionated using Sephadex LH‐20 and silica gel columns when appropriate. The fractions were subjected to thin‐layer chromatography and liquid chromatography‐mass spectrometry analysis and evaluated for their total phenolic content (Folin‐Ciocalteu assay), radical scavenging activity (DPPH assay), cytotoxic activity (MTT assay on the SH‐SY5Y cell line), and ability to generate H2O2 (Amplex Red assay). Chromatographic and phenolic analyses of the fractions indicate that abundant redox‐active phenols are present in all the fractions and that a high amount of prenylated hydroquinone derivatives is present in the apolar ones. In the hexane and dichloromethane fractions, the cytotoxic and antioxidant activities are closely related to their phenolic content, whereas in the methanol fractions, the cytotoxicity is negatively related to the phenolic content and the antioxidant activity is positively related to it. In the same tests, hydroquinone behaves as both strong cytotoxic and antioxidant agent. H2O2 assay shows that C. tamariscifolia fractions and hydroquinone can autoxidize and generate H2O2. Our results suggest that redox‐active phenols produce the pharmacological effects described for C. tamariscifolia and that the hydroquinone moiety of prenylated hydroquinone derivatives is responsible for both cytotoxic (through a pro‐oxidant mechanism secondary to its autoxidation) and antioxidant effects of the apolar fractions.

A red algal species,Polyneura bonnemaisonii(Delesseriaceae, Rhodophyta), is described for the first time in the Atlantic Ocean of Morocco. This is also the first reference of the occurrence of this species in Africa. This species was collected in the lower intertidal to subtidal zones, from Hyayda (north-west of Morocco). The Moroccan specimen is studied in detail and compared with other closely related species. Habitat, geographic distribution, description and illustration of the macroscopic and microscopic characters are presented and discussed in this work.

Français. Deux algues marines nouvelles pour la phycoflore benthique du Maroc sont décrites. Il s’agit d’une Ulvophyceae: Codium tomentosum var. mucronatum et une Rhodophyceae: Aglaothamnion pseudobyssoides. Les deux espèces sont étudiées en détail et des données écologiques sont ajoutées aux descriptions morphologiques et anatomiques.