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....

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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.

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.