Donatella Serio

Changes in the benthic algal flora of Linosa Island (Straits of Sicily, Mediterranean Sea)

Abstract A study of the benthic algal macroflora of Linosa Island (Straits of Sicily, Mediterranean Sea) is presented, aiming to verify possible floristic changes that have occurred in the area, last studied in 1973. We found noticeable changes in the benthic flora, which is now poorer in species than that recorded in the literature (233 species against 305), with a minor decrease in Phaeophyceae and Chlorophyta, and a more significant decrease in the number of Rhodophyta. Only 178 species in the present flora were reported previously, while 127 previously reported were not found during the present study. Conversely, 55 species were newly found. Several species of Fucales, like Cystoseira brachycarpa, C. sauvageauana, C. spinosa, C. zosteroides, Sargassum acinarium and S. trichocarpum, which are characteristic of the Mediterranean Sea photophilic communities on hard substrata and sensitive to any environmental changes, have disappeared.

The Laurencia complex (Rhodophyta, Rhodomelaceae) in the Mediterranean Sea: an overview

Abstract Recent taxonomic studies of the genus Laurencia sensu lato (Ceramiales, Rhodomelaceae) have resulted in the recognition of three genera within the ‘Laurencia complex’: Laurencia sensu stricto, Chondrophycus and Osmundea. A critical examination of all Mediterranean records of taxa referred to Laurencia has shown that three species of Chondrophycus, six species of Osmundea and nine species of Laurencia are present. These taxa are described and illustrated. Laurencia caduciramulosa and L. intricata are reported for the first time from the Mediterranean Sea and from Italy, respectively. A key to the Mediterranean species of the Laurencia complex is given.

FIRST RECORD OF LAURENCIA CHONDRIOIDES (CERAMIALES, RHODOPHYTA) FROM THE MEDITERRANEAN SEA

The occurrence in the Mediterranean Sea of Laurencia chondrioides, first described from the Caribbean Sea, is reported for the first time. The following characters: i) occurrence of secondary pit-connections between epidermal cells; ii) four vegetative pericentral cells produced per axial segment; iii) tetrasporangia produced by pericentral cells, in parallel arrangement, cut off from the mother cells abaxially; iv) spermatangial branches of trichoblast type; v) cystocarps urceolate to conical with carpostome prominent, are reported for the first time. On this basis, the species is attributed to the subgenus Laurencia. An earlier record from the Canary Islands suggests that this species is unlikely to be a recent introduction into the Mediterranean.

The species of Chondrophycus and Laurencia (Rhodomelaceae, Ceramiales) occurring in Dhofar, the Sultanate of Oman

M.J. Wynne, D. Serio, M. Cormaci, and G. Furnari. 2005. The species of Chondrophycus and Laurencia (Rhodomelaceae, Ceramiales) occurring in Dhofar, the Sultanate of Oman. Phycologia 44: 497–509. Fieldwork carried out in the Dhofar region of the Sultanate of Oman has resulted in many collections of marine algae assignable to the related genera Chondrophycus and Laurencia. Observations are made on the following five species of Chondrophycus, all representing first reports for Oman: Chondrophycus ceylanicus (J. Agardh) M.J. Wynne, Serio, Cormaci & G. Furnari comb. nov., C. cruciatus, C. dotyi, C. palisadus, and C. succisus. A first record of Laurencia nidifica is made for Oman, and new collections are documented for the previously reported species L. heteroclada and L. majuscula. A key to the Sultanate of Oman species of the Laurencia complex is given.

Spring Marine Vegetation on Rocky Substrata of the Tremiti Islands (Adriatic Sea, Italy)

Spring aspect of the benthic marine communities on rocky substrata from midlittoral to circalittoral zones of the Tremiti Islands (Adriatic Sea) is described. From a comparison with literature data the disappearance of species characterising well structured infralittoral photophilic communities on rocky substrata like Cystoseira spp. and Sargassum spp., resulted. This finding led us to suppose that a considerable structural deterioration of phytobenthic communities has occurred during the last three decades, probably because of an increase of water turbidity.

On the structure, typology and periodism of Cystoseira spinosa Sauvageau community and of Cystoseira zosteroides C. Agardh community from Eastern coast of Sicily (Mediterranean Sea)

Abstract A study on Cystoseira spinosa community and Cystoseira zosteroides community from Catania (Eastern coast of Sicily) is presented. It is based on monthly samples carried out throughout a year. That permitted to better characterize the communities as regards their periodism and floristic composition. From the comparative examination of samples made, resulted that the communities differ each other mainly in the Cystoseira species since their floristic composition are on the whole quite similar.

The benthic algal flora on rocky substrata of the Tremiti Islands (Adriatic Sea)

ABSTRACT The results of a floristic study of benthic marine macroalgae on rocky substrata from the Tremiti Islands (Adriatic Sea) are presented. The list of taxa at specific and infraspecific level consists of 226 Rhodophyceae, 59 Fucophyceae and 36 Chlorophyceae. Of these 321 taxa, 147 are newly reported from the Tremiti Islands. Data on the reproductive phenology of each species, and comments on some species of particular interest are also given.

Polysiphonia perforans sp. nova (Ceramiales, Rhodophyta) from the Mediterranean Sea

ABSTRACT A new species of the genus Polysiphonia from the Mediterranean Sea is described. It is an ecorticate species, with 4 pericentral cells, showing prostrate axes from which erect axes arise. Rhizoids are formed by pericentral cells in a median position remaining in open connection with them. Erect axes are straight, simple throughout or pseudodichotomous at the base then simple or with one (rarely two-three) orders of branching; trichoblasts and scar cells not observed. Only tetrasporangial plants were found. They show ellipsoid tetrasporangia borne in short straight series, often interrupted by sterile segments. The new species is also characterized by a peculiar habit consisting of prostrate axes, adhering to lower faces of Peyssonnelia spp. by means of rhizoids growing upward, from which erect upright axes perforating thalli of the supporting species arise. A comparison with the related species of Polysiphonia was also carried out.

First record of tetrasporophytes of Polysiphonia funebris De Notaris ex J. Agardh (Rhodomelaceae, Rhodophyta) from the Mediterranean Sea, with taxonomic considerations

Abstract The first record of tetrasporophytes of Polysiphonia funebris from the Mediterranean Sea is reported. Thalli correspond in vegetative characters to the descriptions of the species from literature as well to both holotype and other herbarium specimens studied. The relevant character of the origin of rhizoids, in a median or posterior position, from periaxial cells with which remain in open connection, was detected for the first time. Tetrasporangia are borne in branches or branchlets in short terminal series. They are arranged in an irregular right-handed spiral. From the comparison with both P. balanicola and P. devoniensis resulted that the former is a synonym of P. funebris, while the latter is a distinct species.

On three interesting marine red algae (Ceramiales, Rhodophyta) from the Mediterranean Sea

Abstract Observations on three interesting Ceramiales from the Mediterranean Sea are reported; Ceramium incospicuum Zanardini, Polysiphonia setacea Hollenberg and Rodriguezella pinnata (Kutzing) Schmitz ex Falkenberg. The male reproductive structures on the genus Rodriguezella are described for the first time.