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The association between epizoic algae and animals is well known, and turtles are among the animals that most commonly host epibiont communities. The most studied algal component of the epizoic communities found on turtles is represented by diatoms, while other algal taxa, like the Rhodophyta, are less investigated. During a survey started to study the epibionts associated with loggerhead turtles, Caretta caretta, cared for at the WWF Sea Turtle Rescue Center of Lampedusa Island (Sicily, Italy), specimens of Rhodomelaceae (Rhodophyta) were collected for taxonomic investigation. The resulting vegetative, reproductive, and molecular data of those specimens characterised the new species described here as Melanothamnus testudinis sp. nov. We also evaluated the holotype of Polysiphonia carettia Hollenberg, an epibiont of C. caretta reported from the Mediterranean Sea. This investigation confirmed the distinction of M. testudinis from P. carettia and suggested that previous Mediterranean and Canarian records of the latter species are probably M. testudinis. [ABSTRACT FROM AUTHOR]

The cosmopolitan genus Ceramium Roth (Ceramiaceae), with over 200 currently accepted species, is one of the largest in the Rhodophyta. The genus is characterized by cylindrical or slightly compressed thalli, with axial cells incompletely to completely covered by cortical cells, alternate to pseudo-dichotomous branching and straight to inrolled apices. Despite recent studies, the nomenclature and taxonomy of this genus are still very problematic, linked to the high degree of variation in morphological characters, small thallus sizes, epiphytic habit and the existence of cryptic species. The Mediterranean Sea is reported to have a particularly high diversity of Ceramium species: the North Adriatic Sea, in particular Venice and nearby coasts, was a favourite classical collecting area from where several species were described. In this study we characterize Ceramium sampled from transitional waters of the Venice Lagoon (Italy) by molecular and morphological approaches. Through phylogenetic analyses, using the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) as molecular marker, we identify six distinct taxonomic entities, of which four represent taxa not currently recognized in the Venice Lagoon or the wider Mediterranean Sea. One of these is the poorly known species Ceramium connivens Zanardini, which is non-spiny and fully corticated when mature with short naked internodes developing in older axes. Two entities with erect partially corticated thalli without spines, probably misidentified up to now as Ceramium diaphanum (Lightfoot) Roth, correspond to the new species Ceramium rothianum Wolf et al. and to the forgotten species Ceramium nodosum (Kützing) A.W. Griffiths & Harvey. The last entity, characterized by prostrate axes giving rise to narrow erect incompletely corticated, non-spiny axes, is identified as the rare, poorly known species Ceramium incospicuum Zanardini. [ABSTRACT FROM AUTHOR]

We characterized a new Gracilaria species from the Venice Lagoon, Italy, using molecular analyses based on the plastid large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) and the intergenic RuBisCO spacer (rbcL-rbcS), combined with morphology data. This new entity was recorded on the artificial substrata of the Venice Gulf from March to July, adding to 12 Gracilaria taxa already recorded in the Mediterranean and Adriatic seas. Thalli exhibited a green-yellowish pigmentation with pink shades, and there was dense branching in the distal portions. Tetrasporangia were scattered on thallus cortex and distributed mostly on short, stipitate branchlets. The inner pericarp was connected to the gonimoblast by tubular nutritive cells. The male gametophytic plants formed round-elliptical spermatangial verrucosa-type conceptacles. This species grew attached on artificial rocky substrata of the low midlittoral and upper sublittoral zone in spring and early summer. Molecular analyses based on the plastid-encoded rbcL gene showed a 99.66% nucleotide identity with another Gracilaria sp. from southern Sicily. We compared our rbcL-rbcS spacer sequences with those of two cryptic species, and the phylogenetic analyses confirmed that the Venice populations were a new species. We suggested that the discovery of this new species was not due to an extra-Mediterranean introduction but the consequence of its misidentification as Gracilaria gracilis, which has a similar gross morphology. [ABSTRACT FROM AUTHOR]

Ulva Linnaeus ( Ulvophyceae, Ulvales) is a genus of green algae widespread in different aquatic environments. Members of this genus show a very simple morphology and a certain degree of phenotypic plasticity, heavily influenced by environmental conditions, making difficult the delineation of species by morphological features alone. Most studies dealing with Ulva biodiversity in Mediterranean waters have been based only on morphological characters and a modern taxonomic revision of this genus in the Mediterranean is not available. We report here the results of an investigation on the diversity of Ulva in the North Adriatic Sea based on molecular analyses. Collections from three areas, two of which subject to intense shipping traffic, were examined, as well as historical collections of Ulva stored in the Herbarium Patavinum of the University of Padova, Italy. Molecular analyses based on partial sequences of the rbcL and tufA genes revealed the presence of six different species, often with overlapping morphologies: U. californica Wille, U. flexuosa Wulfen, U. rigida C. Agardh , U. compressa Linnaeus, U. pertusa Kjellman, and one probable new taxon. U. californica is a new record for the Mediterranean and U. pertusa is a new record for the Adriatic. Partial sequences obtained from historical collections show that most of the old specimens are referable to U. rigida. No specimens referable to the two alien species were found among the old herbarium specimens. The results indicate that the number of introduced seaweed species and their impact on Mediterranean communities have been underestimated, due to the difficulties in species identification of morphologically simple taxa as Ulva. [ABSTRACT FROM AUTHOR]

Lagoon environments are particularly subject to the introduction, either accidental or voluntary, of alien species that may cause biological pollution. On the basis of morphological data and molecular analyses ( rbcL and mitochondrial cox2- cox3 spacer sequences) we confirmed the taxonomic identity (previously only hypothesised) of Grateloupia turuturu in both the Lagoon of Venice and the Mar Piccolo basin of Taranto, where it was most probably introduced by shellfish transfers. A detailed morphological description of vegetative and reproductive thalli is given, focusing particularly on the encrusting bases. The bases act as resting structures that are able to survive during unfavourable environmental conditions. In both the Lagoon of Venice and the Mar Piccolo of Taranto, G. turuturu does not yet exhibit invasive behaviour. [ABSTRACT FROM AUTHOR]

Abstract: Here we report the first finding of Hypnea flexicaulis Yamagishi and Masuda in the Mediterranean Sea (Lagoon of Venice, Italy), identified through molecular analyses using the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) and the mitochondrial protein-coding cytochrome c oxidase subunit I (cox1) genes. The phylogenetic reconstruction, based on rbcL+ cox1 multiple alignment, showed that all specimens of H. flexicaulis from Venice, Korea, Philippines and Taiwan were included in a monophyletic group supported by a bootstrap value of 100%. It is highly probable that H. flexicaulis has been introduced from Indo-Pacific populations, in particular the Korean one, probably via ship traffic or shellfish transfers. The use of DNA barcoding combined with morphological observations was, in this case, a rapid way to identify this allochthonous species. [Copyright &y& Elsevier]