In the central Mediterranean Sea, gut contents and feces of 95 turtles captured by bottom trawlers and pelagic longliners fishing in neritic and oceanic areas, respectively, were examined. Benthic prey were more abundant than pelagic, a probable bias due to the higher digestibility of the latter. Animal and plant taxa belonging to 12 Phyla and 20 Classes were observed, with 63 new records of prey species, and Malacostraca, Gastropoda, and Echinoidea were the most commonly occurring animal classes. Results showed a highly opportunistic foraging behavior by the turtles on both live and dead material in the epipelagic zone as well as on all types of seafloor. Benthic taxa were found in turtles as small as 26 cm curved carapace length (CCL), indicating an early use of benthic resources, and also among turtles over a wide size range caught by pelagic longliners. The lack of evidence of a strict oceanic/ pelagic stage and of a clear habitat shift in the observed size range (25 to 80.3 cm CCL), when considered together with other recent findings, challenges the current ontogenetic model of life history for the species. A relaxed model is proposed, with an early short obligate epipelagic stage due to limited diving capacity, followed by the main opportunistic amphi-habitat stage, with a tendency to prefer benthic prey as turtles grow and their benthic foraging efficiency improves. Under this model, temporary or permanent association or fidelity to specific oceanic or neritic zones would vary among individuals or populations according to food availability and oceanographic features in the foraging or migratory areas. KEY WORDS: Sea turtle · Caretta caretta · Diet · Life history · Mediterranean Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 372: [265][266][267][268][269][270][271][272][273][274][275][276] 2008 Mediterranean basin (Margaritoulis et al. 2003). In particular, the area between Sicily (Italy) and Africa is considered among the most important areas for loggerheads and this is where pelagic longliners and bottom trawlers capture high numbers of turtles (Casale et al. 2007a).Diet data from different neritic areas of the basin show markedly different compositions of benthic taxa, an indication of opportunistic feeding (Laurent & Lescure 1994, Godley et al. 1997, Tomas et al. 2001. However, the ecology of loggerhead turtles in the basin is still poorly known. Laurent et al. (1998) hypothesized a transitional stage between the strictly oceanic and neritic stages, in which loggerhead turtles would feed mainly on pelagic prey but also on benthic prey, but this has not yet been adequately investigated through diet analyses. This is not a simple task, since loggerhead turtles in the neritic stage are known to feed throughthe whole water column (Bolten 2003), so that finding pelagic and benthic prey in the same sample (e.g. Tomas et al. 2001) is not proof of a transitional stage.Small loggerhead turtles (minimum size: 29.5 and 22 cm respectively; Casale et al....
Aim We discuss biogeographical hypotheses for the Mediterranean lizard species Podarcis and Teira within a phylogenetic framework based on partial mitochondrial DNA sequences. Methods We derived the most likely phylogenetic hypothesis from our data set (597 aligned positions from the 12S rDNA and phenyl tRNA) under parsimony, distance and maximum likelihood assumptions. Results The species usually included in Teira do not form a strongly monophyletic clade. In contrast, the monophyly of the genus Podarcis is rather well supported. Seven lineages are identified in the genus; in order of appearance within the tree, these are: the Balearic pityusensis and lilfordi pair, the sicula complex, a Tyrrhenian tiliguerta and raffonei pair, muralis, the Siculo‐Maltese filfolensis and wagleriana pair, the Balkan group (erhardi, peloponnesiaca, milensis, melisellensis and taurica), and the Ibero‐Maghrebian group (bocagei, atrata, hispanica and vaucheri). Conclusions The origin of the three European genera of lacertid assayed (Lacerta, Teira and Podarcis) is hypothesized to have occurred in the Oligocene. For Podarcis, a possible scenario of a Miocene diversification is derived from the sequence data, and the zoogeography of the lineages are discussed in relation to the palaeogeography of the Mediterranean. It is hypothesized that in the early history of the genus the main lineages separated by rapid, numerous and close events that produced a starting point very similar to a polytomy, hard to resolve by parsimony analysis of the data set.
The reef building vermetid gastropod Dendropoma petraeum inhabits the warmest waters of the Mediterranean Sea and is considered a threatened marine species. The aim of this study was to characterize its genetic structure throughout its whole distribution range using mitochondrial and nuclear sequence data. Because of its sessile adult lifestyle and lack of a pelagic larval stage, we expected a markedly subdivided population structure with limited levels of gene flow. Fragments of the mitochondrial genes cytochrome c oxidase subunit I (COI) and 16S rRNA (16S), were sequenced, along with the nuclear ribosomal cluster (internal transcribed spacer; ITS) in specimens from 18 localities. Our analyses identified four highly distinct phylogroups separated by a mean divergence of > 14% according to the COI sequence data or > 9% according to 16S, but differing only slightly in morphology. The nuclear data (ITS) indicated a lower substitution rate (divergence among groups of around 1%). These large genetic distances among the four lineages clearly point to the existence of a cryptic species complex within D. petraeum comprising at least four species. Differences in the characteristics of intracapsular larval development and protoconch were also detected among these lineages. The allopatric distribution of these cryptic species supports a predominantly vicariant-based cladogenetic pattern for the genus Dendropoma in the Mediterranean.
In the Ross Sea, biodiversity organisation is strongly influenced by sea-ice cover, which is characterised by marked spatio-temporal variations. Expected changes in seasonal sea-ice dynamics will be reflected in food web architecture, providing a unique opportunity to study effects of climate change. Based on individual stable isotope analyses and the high taxonomic resolution of sampled specimens, we described benthic food webs in contrasting conditions of seasonal sea-ice persistence (early vs. late sea-ice break up) in medium-depth waters in Terra Nova Bay (Ross Sea). The architecture of biodiversity was reshaped by the pulsed input of sympagic food sources following sea-ice break up, with food web simplification, decreased intraguild predation, potential disturbance propagation and increased vulnerability to biodiversity loss. Following our approach, it was possible to describe in unprecedented detail the complex structure of biodiverse communities, emphasising the role of sympagic inputs, regulated by sea-ice dynamics, in structuring Antarctic medium-depth benthic food webs.
BackgroundHematophagy arose independently multiple times during metazoan evolution, with several lineages of vampire animals particularly diversified in invertebrates. However, the biochemistry of hematophagy has been studied in a few species of direct medical interest and is still underdeveloped in most invertebrates, as in general is the study of venom toxins. In cone snails, leeches, arthropods and snakes, the strong target specificity of venom toxins uniquely aligns them to industrial and academic pursuits (pharmacological applications, pest control etc.) and provides a biochemical tool for studying biological activities including cell signalling and immunological response. Neogastropod snails (cones, oyster drills etc.) are carnivorous and include active predators, scavengers, grazers on sessile invertebrates and hematophagous parasites; most of them use venoms to efficiently feed. It has been hypothesized that trophic innovations were the main drivers of rapid radiation of Neogastropoda in the late Cretaceous.We present here the first molecular characterization of the alimentary secretion of a non-conoidean neogastropod, Colubraria reticulata. Colubrariids successfully feed on the blood of fishes, throughout the secretion into the host of a complex mixture of anaesthetics and anticoagulants. We used a NGS RNA-Seq approach, integrated with differential expression analyses and custom searches for putative secreted feeding-related proteins, to describe in detail the salivary and mid-oesophageal transcriptomes of this Mediterranean vampire snail, with functional and evolutionary insights on major families of bioactive molecules.ResultsA remarkably low level of overlap was observed between the gene expression in the two target tissues, which also contained a high percentage of putatively secreted proteins when compared to the whole body. At least 12 families of feeding-related proteins were identified, including: 1) anaesthetics, such as ShK Toxin-containing proteins and turripeptides (ion-channel blockers), Cysteine-rich secretory proteins (CRISPs), Adenosine Deaminase (ADA); 2) inhibitors of primary haemostasis, such as novel vWFA domain-containing proteins, the Ectonucleotide pyrophosphatase/phosphodiesterase family member 5 (ENPP5) and the wasp Antigen-5; 3) anticoagulants, such as TFPI-like multiple Kunitz-type protease inhibitors, Peptidases S1 (PS1), CAP/ShKT domain-containing proteins, Astacin metalloproteases and Astacin/ShKT domain-containing proteins; 4) additional proteins, such the Angiotensin-Converting Enzyme (ACE: vasopressive) and the cytolytic Porins.ConclusionsColubraria feeding physiology seems to involve inhibitors of both primary and secondary haemostasis, anaesthetics, a vasoconstrictive enzyme to reduce feeding time and tissue-degrading proteins such as Porins and Astacins. The complexity of Colubraria venomous cocktail and the divergence from the arsenal of the few neogastropods studied to date (mostly conoideans) suggest that biochemical diversification of neogastropods might be largely...
We investigated the relationships of the muricid subfamilies Haustrinae, Pagodulinae and the genus Poirieria using a molecular phylogenetic approach on a dataset of three mitochondrial genes (12S, 16S and COI). These taxa form a well-supported clade within Muricidae. The phylogenetic analysis suggests that Poirieria is the sister group of Pagodulinae and that Axymene, Comptella, Pagodula, Paratrophon, Trophonella, Trophonopsis, Xymene, Xymenella, Xymenopsis and Zeatrophon are all worthy of genus-level rank within this subfamily. We propose the use of Enixotrophon for a group of species currently classified in Pagodula. The results also support a new taxonomic arrangement in Haustrinae. radula, accessory salivary gland, oesophagus, paraspermatozoa (in males) and bursa copulatrix (in females). Tan (2003) assigned species of Lepsiella Iredale, 1912, Lepsithais Finlay, 1928 and Haustrum Perry, 1811 to Haustrinae and treated Bedeva Iredale, 1924 as a subgenus of Lepsiella, a classification accepted by Barco et al. (2010). Lepsiella and Lepsithais are now considered to be synonyms of Haustrum (Beu , 2004) and the subfamily currently includes two genera and up to 10 species (depending on the author), geographically restricted to New Zealand and southern Australia, with the sole exception of Bedeva paivae (Crosse, 1864), which has been introduced by human agency to South Africa (Kilburn & Rippey, 1982), the Canary Islands and Madeira (Houart & Abreu, 1994). Barco et al. (2012) analysed the phylogenetic relationships of Southern Ocean muricids traditionally assigned to Trophoninae and investigated differences in radular and penial morphology of 12 genera. Evidence was found for a new subfamily, Pagodulinae, comprising seven genera, four of which were based on molecular data:
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