51 research outputs found
Different behavioural profiles between invasive and native nudibranchs: means for invasion success?
No full textIndividual reaction of Godiva quadricolor to a tactile stimulus employed as a behavioural endpoint for measuring the state of alert and the escaping behavio
Molecular phylogenetics and systematics of the bivalve family Ostreidae based on rRNA sequence-structure models and multilocus species tree.
No full textThe bivalve family Ostreidae has a worldwide distribution and includes species of high economic importance. Phylogenetics and systematic of oysters based on morphology have proved difficult because of their high phenotypic plasticity. In this study we explore the phylogenetic information of the DNA sequence and secondary structure of the nuclear, fast-evolving, ITS2 rRNA and the mitochondrial 16S rRNA genes from the Ostreidae and we implemented a multi-locus framework based on four loci for oyster phylogenetics and systematics. Sequence-structure rRNA models aid sequence alignment and improved accuracy and nodal support of phylogenetic trees. In agreement with previous molecular studies, our phylogenetic results indicate that none of the currently recognized subfamilies, Crassostreinae, Ostreinae, and Lophinae, is monophyletic. Single gene trees based on Maximum likelihood (ML) and Bayesian (BA) methods and on sequence-structure ML were congruent with multilocus trees based on a concatenated (ML and BA) and coalescent based (BA) approaches and consistently supported three main clades: (i) Crassostrea, (ii) Saccostrea, and (iii) an Ostreinae-Lophinae lineage. Therefore, the subfamily Crassostreinae (including Crassostrea), Saccostreinae subfam. nov. (including Saccostrea and tentatively Striostrea) and Ostreinae (including Ostreinae and Lophinae taxa) are recognized [corrected]. Based on phylogenetic and biogeographical evidence the Asian species of Crassostrea from the Pacific Ocean are assigned to Magallana gen. nov., whereas an integrative taxonomic revision is required for the genera Ostrea and Dendostrea. This study pointed out the suitability of the ITS2 marker for DNA barcoding of oyster and the relevance of using sequence-structure rRNA models and features of the ITS2 folding in molecular phylogenetics and taxonomy. The multilocus approach allowed inferring a robust phylogeny of Ostreidae providing a broad molecular perspective on their systematics
Different behavioral profiles between invasive and native nudibranchs: means for invasion success?
No full textBehavior is predicted to be a primary determinant of the success of the invasion process during the early phases of colonization. Comparing invaders with sympatric native species may provide a good approach to unravel behavioral traits involved in an invasion process. In this study, we carried out an experimental simulation of the introduction and the acclimatization phase into a new environment and assessed the expression of activity, alertness, and habituation in an invasive Mediterranean population of the South African nudibranch Godiva quadricolor comparing its profiles with those of the sympatric Mediterranean native nudibranchs Cratena peregrina and Caloria quatrefagesi. Individuals of these 3 species were subjected to 3 behavioral tests: spontaneous activity, carried out in the introduction phase (immediately after sampling) and after a week of acclimatization; alert test, in which a potential threat was simulated by means of a tactile stimulus, and habituation test, in which the same alert test stimulus was repeated 5 times at 30-min intervals. The invasive G. quadricolor showed higher levels of exploration activity, thigmotaxis, alertness, and sensitization than the native species. These behavioral traits may represent pivotal drivers of the ongoing invasion process
Further spreading in the Italian seas of already established non-indigenous mollusc species
No full textWe hereby provide new distributional data for alien and possible alien molluscs from the Italian seas, together with a brief
review of their known Italian distribution and updated distributional maps. In particular, Haminoea cyanomarginata is con-
firmed for the Calabrian shores of the Strait of Messina area and is first reported from eastern and western Sicily, therefore
suggesting a natural spreading into the Italian central Mediterranean Sea. Melibe viridis is confirmed for the Ionian
Calabrian shores and Sardinia, where it was previously known from isolated records only. Pinctada imbricata radiata is
first reported as naturally widening its distribution in Sardinia and in the Gulf of Taranto, where new populations are
soon awaited, whilst Aplysia dactylomela is now expanding its range along the Italian Adriatic shores. And last, recent
records of Anadara transversa from the Sabaudia Lake testify the role of lagoon systems as hot-spots for the introduction
and secondary spreading of alien species, and indicate mussel aquaculture as the likely vector of introduction for its
occurrenc
Habitat overlap between bottlenose dolphins and seabirds: a pilot study to identify high-presence coastal areas in the Tyrrhenian Sea.
No full textPioneer settlement of the cold-water coral Desmophyllum dianthus (Esper, 1794) on plastic
No full textLarval settlement is a critical step for sessile benthic species such as corals, whose ability to thrive on diverse natural and anthropogenic substrates may lead to a competitive advantage in the colonization of new environments with respect to a narrow tolerance for a specific kind of substratum. Plastic debris, widespread in marine waters, provides a large, motile, and solid substratum supporting a highly diverse biological community. Here we present the first observation of a floating plastic bottle colonized by the deep-sea coral Desmophyllum dianthus. The density pattern and co-occurring species composition suggest a pioneer behavior of this coral species, whose peculiar morphologic plasticity response when interacting with the plastic substrate (i.e., low density polyethylene) has not been observed before. The tolerance of D. dianthus for such plastic substrate may affect ecological processes in deep water environments, disrupting interspecific substrate competition in the benthic community
Molecular Phylogenetics and Systematics of the Bivalve Family Ostreidae Based on rRNA Sequence-Structure Models and Multilocus Species Tree
No full textThe bivalve family Ostreidae has a worldwide distribution and includes species of high economic importance. Phylogenetics
and systematic of oysters based on morphology have proved difficult because of their high phenotypic plasticity. In this
study we explore the phylogenetic information of the DNA sequence and secondary structure of the nuclear, fast-evolving,
ITS2 rRNA and the mitochondrial 16S rRNA genes from the Ostreidae and we implemented a multi-locus framework based
on four loci for oyster phylogenetics and systematics. Sequence-structure rRNA models aid sequence alignment and
improved accuracy and nodal support of phylogenetic trees. In agreement with previous molecular studies, our
phylogenetic results indicate that none of the currently recognized subfamilies, Crassostreinae, Ostreinae, and Lophinae, is
monophyletic. Single gene trees based on Maximum likelihood (ML) and Bayesian (BA) methods and on sequence-structure
ML were congruent with multilocus trees based on a concatenated (ML and BA) and coalescent based (BA) approaches and
consistently supported three main clades: (I) Crassostrea, (II) Saccostrea, and (III) an Ostreinae-Lophinae lineage. Therefore, the
subfamily Crassotreinae (including Crassostrea), Saccostreinae subfam. nov. (including Saccostrea and tentatively Striostrea)
and Ostreinae (including Ostreinae and Lophinae taxa) are recognized. Based on phylogenetic and biogeographical
evidence the Asian species of Crassostrea from the Pacific Ocean are assigned to Magallana gen. nov., whereas an
integrative taxonomic revision is required for the genera Ostrea and Dendostrea. This study pointed out the suitability of the
ITS2 marker for DNA barcoding of oyster and the relevance of using sequence-structure rRNA models and features of the
ITS2 folding in molecular phylogenetics and taxonomy. The multilocus approach allowed inferring a robust phylogeny of
Ostreidae providing a broad molecular perspective on their systematics
The nightmare of Okenia in the Mediterranean Sea: what are we facing?
No full textNine species of the small nudibranch genus Okenia Menke, 1830 have been reported from the western Mediterranean: Okenia aspersa (Alder & Hancock, 1845), Okenia cupella (Vogel & Schultz, 1970), Okenia elegans (Leucjart, 1828), Okenia hispanica Valdés & Ortea, 1995, Okenia impexa Er. Marcus, 1957, Okenia leachii (Alder & Hancock, 1854), Okenia mediterranea (Ihering, 1886), Okenia pulchella (Alder & Hancock, 1854) and Okenia zoobotryon (Smallwood, 1910). However, except for O. hispanica and O. mediterranea originally described from the Mediterranean Sea, most of the remaining records are doubtful. In this contribution we study and discuss several specimens of Okenia collected in La Grande Motte (France), Sabaudia Lake (Lazio, Italy) and Gallipoli (Lecce, Italy), in order to try to clarify their taxonomic status. All of them were initially identifed as O. zoobotryon but, after a detailed anatomical, molecular and ecological study and comparison with the neotype of this species designated by Pola (2015), it is clear that we are dealing with two other species, both different from O. zoobotryon
<i>Okenia longiductis</i> sp. nov.
No full textA. Specimen from Lago di Sabaudia (Italy). Photograph by A. Macali. B. Specimen from La Grande-Motte (France). Photograph by D. Minchin. C. Egg-masses on Amathia verticillata from La Grande-Motte (France). Photograph by D. Minchin. D. Specimen from Mar Piccolo, Taranto (Italy). Photograph by G. Colucci. Size (alcohol-preserved specimens) ~9 mm maximum length.</p
Relative influence of environmental factors on biodiversity and behavioural traits of a rare mesopelagic fish, Trachipterus trachypterus (gmelin, 1789), in a continental shelf front of the Mediterranean Sea
No full textCoastal environments can be influenced by water body masses with particular physical, chemical, and biological properties that create favourable conditions for the development of unique planktonic communities. In this study, we investigated a continental shelf front at Ponza Island (Tyrrhenian Sea) and discussed its diversity and complexity in relation to major environmental parameters. Moon phase and current direction were found to play a significant role in shaping species abundance and behaviour. During in situ observations, we also provided the first data on the behaviour of juveniles of a rare mesopelagic species, Trachipterus trachypterus, suggesting the occurrence of Batesian mimicry
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