Search

Results of a seasonal study on biomass in an infralittoral population of Iridaea cordata from Terra Nova Bay (Ross Sea, Antarctica) are reported.Thalli were collected during the IX Italian Antarctic Expedition (austral summer 1993–94). The population studied is that living at depths of 4 to 6 m, where the highest density of plants occurred. The highest value of biomass (wet weight 3440 g m-2) was found at the beginning of summer. In that period 72.5% of biomass was from 128 specimens belonging to weight classes 8 (>16 to 32 g) to 10 (>64 g), corresponding to 13.4% of the population in numbers. Small ( 8 to 16 g) to 9 (>32 to 64 g), which numerically represented 18.5% of the population. Data showed that biomass depended mainly on the presence of large heavy specimens, even though they were always few in number. Moreover, the occurrence of such large thalli at the beginning of summer suggests that Iridaea cordata continues to grow during the long antarctic winter.

A check-list of Mediterranean green algae, based on literature records, is given. The distribution of each taxon in the area (which is divided into 16 regions) is reported. The number of species and intraspecific taxa accepted for the Mediterranean Sea under current taxonomy is 214. This list has benefited from the suggestions on taxonomy, nomenclature and regional distribution made by phycological advisers for each region

A study of Mediterranean specimens identified as Laurencia pinnatifida (Hudson) Lamouroux (Ceramiales, Rhodophyta) showed that they have to be referred to L. truncata Kutzing. This species, occurring also in the Atlantic, where it was recorded under other names, shows the following main features: axes compressed; epidermal cells elongate, with secondary pit connections; medullary cells showing abundant lenticular thickenings; tetrasporangia, in parallel arrangement, cut off from the mother cells abaxially; antheridial branches unbranched, inserted in depressions that do not show a row of axial cells at their base. The species is included in the subgenus Laurencia, section Planae. The new subgenus Saitoa (type species L. pinnatifida), including the section Pinnatijidae J. Agardh emend. Furnari et Serio, is proposed. It is characterized by lack of secondary pit connections between epidermal cells and by parallel arrangement of tetrasporangia.

The authors report the results of a floristic study of the benthic macroalgae from Terra Nova Bay (Ross Sea, Antarctica) based on collections made during two Italian expeditions to Antarctica. A brief description, phytogeographic data and, where necessary, taxonomic and nomenclatural observations are given for the 17 taxa encountered (9 Rhodophyceae, 4 Fucophyceae and 4 Chlorophyceae)

A check-list of Mediterranean brown algae, based on literature records, is given. The distribution of each taxon in the area (which is divided into 16 regions) is reported. The number of taxa accepted for the Mediterranean Sea under current taxonomy is 265. This list has benefited from the suggestions on taxonomy, nomenclature and regional distribution made by algological advisers from each region

The authors report on the occurrence in Sicily of three Florideophyceae newly recorded for the Mediterranean Sea: Botryocladia madagascariensis G. Feldmann, Ceramium strobiliforme Lawson et John and Chondria pygmaea Garbary et Vandermeulen. A brief description as well as ecological and phytogeographic data are provided for each species

The question of whether or not Leptophytum (Corallinaceae, Rhodophyta) should be recognised as a distinct genus has been addressed using new data generated from type and other specimens combined with analyses of previously published data from various authors. The results have shown that none of the criteria proposed to separate Leptophytum from Phymatolithon are reliable at generic level. Some lead to the exclusion of type species from genera, others are impossible to assess because information is lacking for virtually all included species, others have character states that intergrade and thus are unsuitable and still others appear to be useful for separating species but not genera. Most of the character states proposed as diagnostic of Leptophytum are unknown or are not present in most of the species that were explicitly included in the recent proposed re-instatement of the genus and, in some cases, species included in Leptophytum show the opposing character state for Phymatolithon. No serious conflict occurs between the holotype fragments of Leptophytum laeve (the type species of Leptophytum) and the designated epitype and the designation of an epitype is fully justified because all of the characters evident in the holotype are demonstrably ambiguous and could apply to more than one species. Moreover, new evidence supports the probable conspecificity of the holotype and the designated epitype and reinforces the conclusion that Leptophytum should not be recognised as a genus distinct from Phymatolithon. Nomenclaturally, the correct authorship of the name of the type species of Leptophytum is L. laeve Adey and not L. laeve (Str�mfelt) Adey or L. laeve (Foslie in Rosenvinge) Adey, and for purposes of priority, the name Leptophytum laeve dates from 1966.

Specimens of Antithamnionella elegans (Berthold) Cormaci et Furnari (Ceramiaceae, Rhodophyta) with an undescribed arrangement of whorl-branchlets (opposite and decussate) are recorded from the Mediterranean Sea. Comparisons of Antithamnionella elegans with Antithamnion sublittorale Setchell et Gardner and Antithamnionella breviramosa (Dawson) Wollaston ex Womersley et Bailey showed that these taxa are conspecific. The only significant difference among these taxa involves the arrangement of the whorl-branchlets; this is not considered sufficient to separate them as species, but only as varieties. The following varieties are proposed: Antithamnionella elegans v. elegans (syn. A. breviramosa), with usually three whorl-branchlets per whorl; A. elegans v. sublittoralis (Setchell et Gardner) comb. et stat. nov., with two distichous whorl-branchlets; A. elegans v. decussata var. nov., with two whorl-branchlets decussately arranged; A. elegans v. boergesenii var. nov., with four to five whorl-branchlets ...

The authors point out the presence near Augusta (Siracusa, Sicily) of fertile tetrasporophytes of Cottoniella filamentosa (Howe) Boergesen var. algeriensis (Schotter) Womersley and Shepley (Ceramiales, Rhodomelaceae, Sarcomenioideae). Tetrasporocysts, tetrahedrally divided, lie in two parallel rows in branches of indefinite growth. They are produced by the two lateral pericentral cells of each axial cell. Some taxonomic reflections and a key to the species of Cottoniella complete this work.

On the occurrence in Southern Italy of some benthic marine algae rare to the Mediterranean Sea. - The Authors report the occurrence along the coast of Southern Italy of the following species that resulted rare to the Mediterranean Sea: Antithamnion piliferum Cormaci et Furnari; Bonnemaisonia asparagoides (Woodward) C. Agardh (tetrasporophyte); Corynophlaea flaccida Kuetzing; Fosliella farinosa (Lamouroux) Howe: of this very common species, the occurrence of thalli with propagules is reported; Hypnea cervicornis J. Agardh; Jania adherens Lamouroux, new to Italy; Mesogloia lanosa P.L. et H.M. Crouan, new to Italy; Pneophyllum confervicolum (Kuetzing) Chamberlain f. minutulum (Foslie) Chamberlain, new to the Mediterranean Sea; Polystrata fosliei (Weber van Bosse) Denizot, new to Italy; Rhodymenia delicatula Dangeard; Spermothamnion johannis G. Feldmann-Mazoyer: of this common species, the occurrence of bisporocysts in monoic gametophytes is reported; Vickersia baccata (J. Agardh) Karsakoff.

The floristic knowledge of benthic marine algae of southern Italy appears irregular and not yet complete: up to now, in fact, there are large areas not sufficiently studied (e.g. coast of Calabria and Apulia). Nevertheless the availability of quite complete floras of some areas: gulf of Naples, W-Sicily, the Straits of Messina, the northern part of the eastern Sicilian coast, the southern part of the eastern Sicilian coast and the island of Linosa, permits to get an idea of general characteristics of algal flora of this region. This flora appears very rich of species (over 650). The degree of floristic similarity among ten Mediterranean areas (the above mentioned six areas of southern Italy as well as Catalan coast, cote des Alberes, Adriatic sea and coast of Greece) was established. A hierarchical clustering of these floras was carried out. The results are expressed in a dendrogram. A noticeable similarity among the floras can be drawn from the dendrogram since they are linked above the 50% leve...

Observations on the seaweeds on the Island of Lachea. — Within the frame of the research on seaweeds in the Eastern part of Sicily which is being carried out at the Botanical Department of Catania University, the AA. have undertaken a study on the seaweeds to be found on the Island of Lachea. The material has been collected from the supralittoral to the infralittoral. One hundred and thirty-five species have been identified and data about the local distribution and habitat have been given. The following species are new to Sicily: Spatoglossum solierii (Chauv.) Kuetz., Bonnemaisonia asparagoides (Woodw.) Ag., Gelidiella ramellosa (Kuetz.) Feld. et Ham., Antithamnion cruciatum (C. Ag.) Naeg. var. profundum G. Feld., Antithamnion plumula var. bebbii (Reinsch) J. Feld., Ceramium bertholdi Funk, Ceramium codii (Richards) G. Maz., Spermothamnion repens (Dillw.) K. Ros. var. flagelliferum (De Not.) Feld., Griffithsia barbata (Smith) C. Ag., Polysiphonia biformis Zan., Lophocladia lallemandi (Mont.) Schm...

Preliminary studies on the marine phythobenthic communities in the Straits of Sicily and adjacent islands. — The results of algological researches carried out by the Gruppo di Algologia of the S.B.I. in the Straits of Sicily and adjacent islands are reported. 288 species have been collected, 275 of which have been identified: 160 were Rhodophyta, 62 Phaeophyta, 32 Chlorophyta, 16 Cyanophyta and 2 Angiospermae. The vegetational research leads to the following conclusions: 1 - the harbour areas (Pantelleria, Malta: loc. 1 and 11) show a nitrophile vegetation, particulary near La Valletta where an almost pure population of Pterocladia pinnata is found; 2 - there are important biogeographical differences between Pelagie islands (Lampedusa, Linosa) and Pantelleria. In fact the former ones have an algal flora composed mostly of eastern mediterranean species, whilst the latter shows strong affinities with the north-african basin, as is demonstrated by the rich well developed belt of Cystoseira sedoides;...

First record of Streblonemopsis irritans Valiante from the Ionian Sea. - The occurrence near Catania (Eastern Sicily) of fertile specimens of Streblonemopsis irritans Valiante (Phaeophyta, Ectocarpaceae) (on Cystoseira zosteroides (Turner) C. Agardh), up to now recorded only from the type locality (Gulf of Naples), France (Cote des Alberes) and Spain (Catalan coast), is reported. The hypothesis that the distribution of both S. irritans and its host C. zosteroides could overlap, is put forward.

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.

Results of a study on summer biomass in aninfralittoral population of Phyllophora antarctica A.et E. S. Gepp from Terra Nova Bay (Ross Sea,Antarctica) are reported. The population studied grewat depths of 5 to 12 m. The highest value of biomass(1548 wet g m−2) was found at the end of January at6 m depth. Data showed that biomass depended mainly onthe presence or absence of large heavy specimens, eventhough these were always few in number. Moreover, thevery high number of specimens in weight classes 1 (upto 0.03 wet g) and 2 (> 0.03 to 0.06 wet g) recordedfrom December to January showed a relevant productionof new thalli in that period; the decrease of thetotal number of thalli from 8832 counted on 30December to 4384 counted on 10 February, showed someself-thinning in the population; the occurrence ofnumerous thalli belonging to weight classes 3 (>0.06 to 0.125 wet g), 4 (> 0.125 to 0.25 wet g) and5 (> 0.25 to 0.5 wet g) just at the end of December,allows to conclude that P. antarctica continues togrow, although at low rate, during the period ofwinter darkness. Finally, both the low number ofthalli of weight classes 6 (> 0.5 to 1 wet g) and 7(> 1 to 2 wet g) and the absence of thalli of theweight class 8 (> 2 wet g), recorded at the end ofDecember, indicate that most of specimens reachingduring the winter such weight classes (due to theirability to dark growth), died before summer.