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The mysterious food source of anguilliform leptocephali has been difficult to understand, so this review evaluates potential interrelationships among recent discoveries on this subject. There are typically few identifiable gut-content objects in leptocephalus intestines, which usually contain amorphous materials. Gut content observation studies and stable isotope research have suggested that marine snow detrital-type particles are a food source, but this was difficult to validate. Recent gut-content DNA-sequence analyses indicated that small 4-25 mm Sargasso Sea European eel larvae, Anguilla anguilla, frequently ingest calycophoran siphonophore tissues as well as other taxa not likely to be ingested individually. A high-magnification photographic study of Sargasso Sea leptocephalus gut contents recently detected possible hydrozoan tentacles and apparent fatty acid-rich single-celled, heterotrophic thraustochytrid protists (class Labyrinthulomycetes), which have been found in marine snow in previous studies, but are not amplified by some DNA primers. Calycophoran siphonophores are abundant in the Sargasso Sea and have extensive tentacle arrays and short-lived eudoxid reproductive stages that might be appropriate sizes to be eaten directly or contribute to marine snow aggregates. The two groups may be interrelated because thraustochytrids are ubiquitously present decomposers that colonize detrital materials in oceanic and coastal ecosystems, so both siphonophore tissues and thraustochytrids may be present in marine snow consumed by European eel and other leptocephali. Therefore, future research on what leptocephali consume as food should be approached from a size-scaling perspective using systematic direct gut-content observations in combination with appropriate primers for next-generation DNA sequencing., Author(s): Michael J. Miller [sup.1] [sup.2], Reinhold Hanel [sup.3], Eric Feunteun [sup.4] [sup.5], Katsumi Tsukamoto [sup.1] [sup.2] Author Affiliations: (1) grid.260969.2, 0000 0001 2149 8846, Department of Marine Science and [...]

Sequence variation in the mitochondrial control region was studied in the Mediterranean rainbow wrasse (Coris julis), a species with pronounced pelagic larval phase inhabiting the Mediterranean Sea and the adjacent coastal eastern Atlantic Ocean. A total of 309 specimens from 19 sampling sites were analysed with the aim of elucidating patterns of molecular variation between the Atlantic and the Mediterranean as well as within the Mediterranean Sea. Phylogeographic analyses revealed a pronounced structuring into a Mediterranean and an Atlantic group. Samples from a site at the Moroccan Mediterranean coast in the Alboran Sea showed intermediate frequencies of 'Mediterranean' and 'Atlantic' haplotypes. We recognised a departure from molecular neutrality and a star-like genealogy for samples from the Mediterranean Sea, which we propose to have happened due to a recent demographic expansion. The results are discussed in the light of previous studies on molecular variation in fish species between the Atlantic and the Mediterranean and within the Mediterranean., Author(s): Carmelo Fruciano [sup.1] , Reinhold Hanel [sup.2] , Paul V. Debes [sup.3] , Concetta Tigano [sup.1] , Venera Ferrito [sup.1] Author Affiliations: (1) grid.8158.4, 0000000417571969, Dipartimento di Biologia 'M. [...]