Search

This article gives an up-to-date review of the status of and main changes in benthic algal flora that have occurred in recent decades along the Italian Adriatic coastline. Common traits among the main structural/functional changes observed and their causes are discussed. A synthesis of the challenges to and prospects of filling gaps in the data, ecological knowledge and protection measures are also given.

A study was carried out to determine the status and disposition of Corallinaceae recorded from the Ross Sea (Antarctica), viz. Clathromorphum lemoineanum, Leptophytum coulmanicum, L. laeve and L. foecundum. A re-examination of the type of Lithothamnion coulmanicum (basionym of Leptophytum coulmanicum) showed that it is referable to the genus Phymatolithon because it possesses epithallial cells whose outermost walls are rounded to flattened and meristem cells that are as short as or shorter than their immediate inward derivatives. Such characters were also evident in specimens from McMurdo Sound. Moreover, because all the specimens studied had a conceptacle chamber roof c. 300 μm in diameter, a thallus thickness of up to 1 mm, and buried old conceptacles, they are conspecific with P. foecundum. Studies of specimens from Terra Nova Bay identified as C. lemoineanum and of specimens from Franklin Island identified as L. laeve showed that they should all be referred to P. foecundum. Furthermore, judging by the description and illustrations given by Zaneveld & Sanford [Blumea 26: 205-231 (1980)], records of P. foecundum (as L. foecundum) from Cape Hallett and Moubray Bay can be confirmed. Therefore, P. foecundum is the only member of Corallinaceae confirmed to occur in the Ross Sea (Antarctica).

The red algae Chondrophycus patentirameus (Montagne) Nam (‘patentiramea’) and L. paniculata (C. Agardh) J. Agardh were investigated on the basis of type material and recent collections. Both species show the following features: (i) production of two vegetative pericentral cells from each axial segment; (ii) absence of secondary pit connections between cortical cells; (iii) lack of projecting cortical cells near the apex; (iv) absence of lenticular thickenings in the walls of medullary cells; and (v) perpendicular arrangement of tetrasporangia, each of which is produced from the second pericentral cell in each fertile segment with no additional tetrasporangial pericentral cells. However, C. patentirameus has a stoloniferous holdfast, divaricate branching (with branches arising at angles up to 90°) and non-palisade-like superficial cortical cells, whereas L. paniculata has a discoid holdfast, non-divaricate branching and a palisade-like cortical layer. From this study it is concluded that C. patentirameus (...

Osmundea maggsiana Serio, Cormaci et G. Furnari sp. nov. (Ceramjales, Rhodophyta) is described from the Mediterranean Sea. Thalli are terete, rigid in texture, and irregularly ramified and have as many as three orders of branching. Branches and branchlets are irregularly alternate to spirally (seldom suboppositely) arranged. Epidermal cells do not protrude at the ends of branchlets and have no secondary pit connections; in transverse section they are radially elongate and palisadelike. Vegetative axial segments have two pericentral cells. Tetrasporangia, produced from epidermal cells, are cut off laterally from the mother cells. The two cover cells are aligned parallel to the stichidial axis in surface view. Male gametophytes have reproductive structures of the ‘filament’ type. Spermatangial branches are simple, terminating in one or two (rarely three) spherical sterile cells and are inserted in cuplike depressions located at the bifurcation of branchlets. The new species resembles Osmundea hybri...

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.

A study of Mediterranean specimens identified as Pseudolithophyllum expansum, Lithophyllum expansum sensu Lemoine and Pseudolithophyllum cabiochiae have shown that the taxa represent the same species and the names (except P. expansum, which is a heterotypic synonym of Mesophyllum lichenoides) represent heterotypic synonyms of Melobesia frondosa, previously treated as a synonym of Lithophyllum grandiusculum, and here considered as a distinct species, Lithophyllum frondosum. All specimens have tetrasporangial conceptacles with a diameter greater than 300 μm, and pore canals that narrow towards the top, with the cells adjacent to them oriented more or less obliquely to the roof surface and projecting into, but not completely occluding, the canal. The above characters are shown also by L. bermudense, which is here considered as a further heterotypic synonym of L. frondosum.

News on both the structure and the periodism of the communities with Cystoseira from the Mediterranean Sea based on literature data, are presented. In order to a better knowledge of such communities, the opportunity of a standardized methodology based on a preliminary study of the qualitative minimal area, on monthly samples to be carried out throughout a year as well as on observations on the vertical distribution of species within the community, is suggested.

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.

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.