Cinzia Gravili

Epibiotic Vibrio Luminous Bacteria Isolated from Some Hydrozoa and Bryozoa Species

Luminous bacteria are isolated from both Hydrozoa and Bryozoa with chitinous structures on their surfaces. All the specimens of the examined hydroid species (Aglaophenia kirchenpaueri, Aglaophenia octodonta, Aglaophenia tubiformis, Halopteris diaphana, Plumularia setacea, Ventromma halecioides), observed under blue light excitation, showed a clear fluorescence on the external side of the perisarc (chitinous exoskeleton) around hydrocladia. In the bryozoan Myriapora truncata, luminous bacteria are present on the chitinous opercula. All the isolated luminous bacteria were identified on the basis of both phenotypic and genotypic analysis. The isolates from A. tubiformis and H. diaphana were unambiguously assigned to the species Vibrio fischeri. In contrast, the isolates from the other hydroids, phenotypically assigned to the species Vibrio harveyi, were then split into two distinct species by phylogenetic analysis of 16S rRNA gene sequences and DNA–DNA hybridization experiments. Scanning electron microscopy analysis and results of culture-based and culture-independent approaches enabled us to establish that luminous vibrios represent major constituents of the bacterial community inhabiting the A. octodonta surface suggesting that the interactions between luminous bacteria and the examined hydrozoan and bryozoan species are highly specific. These interactions might have epidemiological as well as ecological implications because of the opportunistic pathogenicity of luminous Vibrio species for marine organisms and the wide-distribution of the hydrozoan and bryozoan functioning as carriers.

The cnidarian premises of metazoan evolution: From triploblasty, to coelom formation, to metamery

Abstract The hydromedusan subumbrellar muscle tissues originate from a mass of endo‐ and ectoderm derived cells proliferating inwardly. This mass of cells, called entocodon, is separated by the ecto‐and endoderm through a layer of extracellular matrix, thus forming a locally triploblastic arrangement of tissues. By cavitation and differentiation, the entocodon gives rise to the striated and smooth muscle layers of the subumbrella. The structure of the striated muscle is histologically identical to that described for triploblasts, where striated muscle is mainly mesodermic. Together with the mode of development, this suggests that not all Cnidaria are diploblastic and that the subumbrellar cavity is a coelom‐like structure. The subumbreHar cavity is formed late in ontogeny, whereas the coelom in higher animals is normally formed during embryonic development. Instead of remaining closed, the subumbrella becomes open, with the muscular mesothelium in contact with the environment. This view of cnidarian struc...

A survey of Zanclea, Halocoryne and Zanclella (Cnidaria, Hydrozoa, Anthomedusae, Zancleidae) with description of new species

Abstract The genera Zanclea, Halocoryne and Zanclella are surveyed, with description of all known species, including eight new ones of Zanclea (Z. bomala, Z, divergens, Z. fanella, Z. giancarloi, Z. medusopolypata, Z. retraduis, Z. gilii, Z. hirohitoi), two new species of Halocoryne (H. frasca, H. pirainoid), and two new ones of Zanclella (Z. diabolica, Z. glomboides). For most species, the description covers the whole life cycle. The hydroids of this group can be symbiotic with either bryozoans, bivalves, or corals and only few species are not substrate‐specialist. Symbiotic relationships led to polymorphism and colony integration with the hosts. The morphologies of hydroid and medusa stages are often not consistent, so that species with very derived hydroids have non‐derived medusae (e.g., Halocoryne pirainoid), or species with very derived medusae have non‐derived hydroids (e.g., Zanclella diabolica). The architecture of the newly released medusae of Zanclella is exceptional due to a sharp compression of the exumbrella and of the presence of just two radial canals. A phylogenetic scenario is suggested, in spite of the inconsistencies in the rates of change in the two main stages of the cycle.

Nonindigenous species along the Apulian coast, Italy

Thirty-eight nonindigenous marine species (NIS) (macroalgae, sponges, hydrozoans, molluscs, polychaetes, crustaceans, ascidiaceans and fish), are reported from the Apulian coast of Italy. Shipping, aquaculture and migration through the Suez Canal are the main pathways of introduction of the NIS. In Apulian waters, 21% of NIS are occasional, 18% are invasive and 61% are well-established. It is highly probable that more NIS will arrive from warm-water regions, because Mediterranean waters are warming. Furthermore, some of the successful NIS must have the ability to become dormant in order to survive adverse conditions, either seasonal or during long journeys in ballast waters. The identification of NIS depends greatly on the available taxonomic expertise; hence the paucity of taxonomists hinders our knowledge of NIS in our seas. We propose the creation and maintenance of a network of observatories across the Mediterranean to monitor the changes that take place along its coasts.

The rediscovery of Codonorchis octaedrus (Hydroidomedusae, Anthomedusae, Pandeidae), with an update of the Mediterranean hydroidomedusan biodiversity

Abstract Codonorchis octaedrus is recorded for the first time since its discovery by Haeckel in 1879. A hydroid colony collected in a cave of the Apulian Coast (between the Ionian and the Adriatic Seas) produced several medusae which have been reared to maturity. This is the first complete description of the species, which was previously considered as doubtful, as was the genus Codonorchis. The diagnostic features for the genus are: hydroid small, naked, sessile, with a single row of few tentacles, gono‐phores on hydrorhiza, medusa with apical projection with apical process from the manubrium, perradial, interradial and adradial ocellate bulbs, two perradial tentacles, horseshoe‐shaped interradial gonads, small mesenteries. The list of Mediterranean hydroidomedusae is updated with the new (or overlooked) records since the last published list (1993). The increase in species number is great (about 10%), showing that the knowledge of biodiversity of even a well‐studied sea as the Mediterranean is far from be...

Vibrio harveyi Associated with Aglaophenia octodonta (Hydrozoa, Cnidaria)

A previously unknown association between a luminous bacterium, Vibrio harveyi, and a benthic hydrozoan, Aglaophenia octodonta, is described. Aglaophenia hydrocladia showed a clear fluorescence in the folds along the hydrocaulus and at the base of the hydrotheca, suggesting the presence of luminous bacteria. This hypothesis was confirmed by isolation of luminous bacteria from Aglaophenia homogenates. Phenotypic characterization of bacterial isolates was performed by several morphological, biochemical, and cultural tests, completed with 16S rDNA sequence analysis. All the isolates were referred to a single species: V. harveyi. The association between V. harveyi and A. octodonta has epidemiological as well as ecological significance. Therefore, A. octodonta may function as habitat “islands” providing a unique set of environmental conditions for luminous bacteria colonization, quite different from those already recorded from the plankton for other Vibrio species.

The life cycle of Gastroblasta raffaelei (Cnidaria, Hydrozoa, Leptomedusae, Campanulariidae) and a review of the genus Gastroblasta

The genus Gastroblasta was proposed by Keller in 1883 for a campanulariid medusa from the Red Sea, G. timida, with round umbrella, multiple radial canals and multiple manubria. A second species, G. raffaelei, with elliptic umbrella, multiple manubria and radial canals, and a great tendency to fission, was subsequently described from the Mediterranean Sea by Lang in 1886. A third species with multiple manubria was described by Mayer in 1900 from Tortugas: Multioralis ovalis (currently ascribed to Gastroblasta). The complete life cycle of a species of Gastroblasta, whose polyp stage was collected inside sponges from the Ligurian Sea and the Ionian and Adriatic Seas, is described. The first stage of medusa development is a typical Clytia with four radial canals and four tentacles, then the medusa becomes similar to G. ovale, to subsequently acquire the typical morphology of G. raffaelei. The species G. timida and G. raffaelei are considered as valid representatives of the genus, sharing the characters of multiple manubria and radial canals. The medusa of G. ovale has a diagonal canal system, instead of multiple radial canals, sharing with Gastroblasta the presence of multiple manubria only: it is proposed to resurrect the genus Multioralis to accommodate it.

The non-Siphonophoran Hydrozoa (Cnidaria) of Salento, Italy with notes on their life-cycles: an illustrated guide

The majority of Hydrozoa is represented by not readily noticeable, small species. In recent decades, however, taxonomic knowledge of the group has increased worldwide, with a significant number of investigations focused on the Mediterranean Sea. Over more than two decades, 115 species of hydrozoans were recorded from coastal waters along nearly 300 km of the Salento Peninsula (Apulia, Italy). For each species, records from different collections were merged into single sheets of a general database. For each species, the following information is reported: description, cnidome, biology, occurrence in Salento, worldwide distribution, and bibliography. Descriptions refer to the benthic hydroid stage and, when present, also to the planktonic medusa stage. The 115 species of Hydrozoa, recorded along the Salento coastline, represent 25% of the Mediterranean Hydrozoa fauna (totaling 461 species), and nearly 3% of 3,702 worlds known species covered in a recent monograph. Four species are non-indigenous, three of them with invasive behavior (Clytia hummelincki, Clytia linearis, and Eudendrium carneum), and one species now very common (Eudendrium merulum) in Salento. The complete life cycle of Clytia paulensis (Vanhöffen, 1910) is described for the first time.

Erratum to: Alien species along the Italian coasts: an overview

We present a contribution to the knowledge of marine and brackish water alien species (infraspecific taxa included) recorded along the Italian coasts. The Italian Peninsula, with over 7,000 km of coastline, is located in the center of the Mediterranean Sea, splitting the Western and the Eastern basins. Data were collected from published material, mostly authored by the experts of different marine taxa participating in the ‘‘Allochthonous Species Group’’ of the Italian Society of Marine Biology (SIBM). The data have been reviewed according to the taxonomic expertise of the authors and are organized in a referenced database containing information on each species about: distribution along Italian coasts, the native range, most probable vectors of introduction, population status and impact. The A. Occhipinti-Ambrogi (&) A. Marchini DET-Dipartimento di Ecologia del Territorio, University of Pavia, Via S.Epifanio 14, 27100 Pavia, Italy e-mail: occhipin@unipv.it G. Cantone Dipartimento di Biologia Animale ‘‘M. La Greca’’, University of Catania, Via Androne 81, 95124 Catania, Italy A. Castelli Dipartimento di Biologia, University of Pisa, Via Derna 1, 56126 Pisa, Italy C. Chimenz Dipartimento di Biologia Animale e dell’Uomo, University ‘‘La Sapienza’’ of Roma, Viale Università 32, 00185 Rome, Italy M. Cormaci G. Furnari G. Giaccone Dipartimento di Botanica, University of Catania, Via A. Longo 19, 95125 Catania, Italy C. Froglia CNR-ISMAR, Sede Ancona, Largo Fiera della Pesca, 60125 Ancona, Italy M. C. Gambi Stazione Zoologica ‘‘Anton Dohrn’’, Benthic Ecology Group, Villa Dohrn, Punta S. Pietro, 80077 Ischia, Napoli, Italy A. Giangrande C. Gravili S. Piraino CONISMA-Consorzio Nazionale Interuniversitario per le Scienze del Mare (ULR Lecce), DiSTeBA-Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy F. Mastrototaro Dipartimento di Biologia Animale ed Ambientale, University of Bari, Via Orabona 4, 70125 Bari, Italy C. Mazziotti ARPA Emilia-Romagna, Struttura Oceanografica Daphne, Viale Vespucci 2, 47042 Cesenatico, FC, Italy L. Orsi-Relini DipTeRis-Dipartimento per lo studio del Territorio e delle sue Risorse, University of Genoa, Corso Europa 26, 16132 Genoa, Italy

Fluorescence distribution pattern allows to distinguish two species of Eugymnanthea (Leptomedusae: Eirenidae)

The auto-fluorescence patterns of the medusae observed under a fluorescent microscope with blue light excitation allows to distinguish two species of Eugymnanthea , this even when they are still attached to the hydroid as small medusa buds despite the occurrence of a sex-dependant pattern in E. japonica . A total of four distribution patterns of green fluorescence, including non-fluorescence, could be found. Three of them are found in E. japonica , called ‘subumbrellar fluorescence type’ except for non-fluorescence, while another type is found in E. inquilina , called ‘umbrellar margin fluorescence type’. During the short life of the medusa the latter type remained invariable for up to six days in E. inquilina , while the pattern observed for up to seven days in E. japonica changed sometimes, but it always remained distinguishable from the pattern found in E. inquilina . Therefore, the fluorescence pattern is a reliable taxonomic character. Fluorescence was not found in unfertilized eggs, planulae 2–8 days old, parthenogenetically produced larvae, or in the hydroids of the two species. The auto-fluorescent and possible bioluminescent tissues of these Eugymnanthea medusae could have some unknown biological significance.