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Fish diets provide information that can be used to explore and model complex ecosys- tems, and infer resource partitioning among species. The exhaustive sampling of prey items captured by each species remains, however, a demanding task. Therefore, predicting diets from other vari- ables, such as functional traits, may be a valuable method. Here, we attempted to predict trophic guild and diet overlap for 35 fish species using 13 ecomorphological traits related to feeding ecology. We compared linear discriminant analysis and random forest (RF) classifiers in their ability to predict trophic guild. We used generalized dissimilarity modelling to predict diet overlap from functional dis- tances between species pairs. All models were evaluated using the same cross-validation procedure. We found that fish trophic guilds were accurately predicted by an RF classifier, even with a limited number of traits, when no more than 7 guilds were defined. Prediction was no longer accurate when finer trophic guilds were created (8 or more guilds), whatever the combination of traits. Furthermore, predicting the degree of diet dissimilarity between species pairs, based on their ecomorphological traits dissimilarities, was profoundly unreliable (at least 76% of unexplained variation). These results suggest that we can predict fish trophic guilds accurately from ecomorphological traits, but not diet overlap and resource partitioning because of inherent versatility in fish diets. More generally, our sta- tistical framework may be applied to any kind of marine organism for which feeding strategies need to be determined from traits.

The epidermis of the free-living typhloplanids Mesostoma viaregginum and M. productum (Mesostominae) is described. In both species, the epidermis has polarized cells with nuclei located at the basal part of the cell, whereas mitochondria are in the apical one. The epidermis is entirely covered by microvilli and locomotory cilia anchored in the cytoplasm by vertical and horizontal rootlets. Rootlets exhibit distinct length and periodic structure in the two species. Furthermore, in each species vertical and horizontal rootlets possess different periodic structure. The pattern of termination of microtubules in epidermal cilia is described for the first time in the Typhloplanida; central microtubules shift along one axonemal side, doublets 1 and 6–9 lose their microtubule B, and gradually peripheral doublets become singlets. Finally, an electron-dense material caps the tip of the cilia. This pattern of termination closely resembles that of Temnocephalida, Kalytorhynchia, and Dalyelliida examined so far, but differences exist.

Electron microscopy of the testes of the free-living flatworm Mesocastrada fuhrmanni collected from temporary freshwater ponds shows stages of spermiogenesis that are like other species of the Typhloplanidae. Spermiogenesis in Mesocastrada fuhrmanni is characterized by the presence, in the spermatid, of a differentiation zone underlain by peripheral microtubules and centered on two centrioles with an intercentriolar body. Two flagella of the 9+“1” pattern of the Trepaxonemata grow out in opposite directions from the centrioles. The flagella undergo a latero-ventral rotation, and a subsequent disto-proximal rotation of centrioles occurs in the spermatid. The former rotation involves the compression and the detachment of a row of cortical microtubules, and allows us to recognize a ventral from a dorsal side. Two features are of special interest at the end of differentiation: peripheral cortical microtubules lie parallel to the sperm axis near the anterior tip, but microtubules become twisted (about 40° with reference to the gamete axis) near the posterior extremity; in the same way, the posterior tip of the nucleus is spiralled. As far as we know, these features are observed for the first time in the Typhloplanidae. The pattern of spermiogenesis and the ultrastructural organization of the spermatozoon are compared with the available data on Typhloplanoida and in particular, species of the Typhloplanidae family.

The ultrastructure of the epidermis and the protonephridia of the free-living rhabdocoel Mesoscastrada fuhrmanni is described. The epidermis consists of polarized cells, the nucleus located in the basal part of the cell and the mitochondria in the apical part. The surface is entirely covered by cilia anchored in the cytoplasm by horizontal and vertical striated rootlets. Cilia of the flame bulbs also have horizontal and vertical striated rootlets. The weir apparatus of the cyrtocyte is composed of a single row of ribs connected by a thin “membrane” of extracellular material. Bundles of microtubules, located in the ribs originate in the centrioles. Epidermal cells and flame bulbs of M. fuhrmanni closely resemble those of the other Typhloplanoida examined so far.

The indicator value (Ind Val) method which combines measures of fidelity and specificity has been used in a study on wild boar parasites in Corsica during 2001–2003. Because of its resilience to changes in abundance,IndValis a particularly effective tool for ecological bioindication. TheInd Valmethod showed how season can influence the occurrence of parasite species in the wild boar, and also identified parasites as bioindicators relative to host age. The randomization test identified five parasite species having a significant indicator value for the season (the ticks,Hyalomma aegyptiumandRhipicephalus sanguineus, the louse,Haematopinus suisand the nematodesGlobocephalus urosubulatusandAscaris suumand two indicator species of an age class (the nematodesG. urosubulatusandMetastrongylussp.). Data on species composition and infection levels would help improve the monitoring and management of parasitism in Suidae populations.

Spermiogenesis in Mesostoma viaregginum begins with the formation of a zone of differentiation containing striated rootlets, two centrioles, and an intercentriolar body in-between. These centrioles generate two parallel free-flagella with the 9+“1” pattern of the Trepaxonemata growing out in opposite directions. Spermatid differentiation is characterised by a 90° latero-ventral rotation of flagella and a subsequent disto-proximal centriolar rotation, with a distal cytoplasmic projection. The former rotation involves the compression of a row of cortical microtubules and allows recognising a flagellar side and an aflagellar side in the late spermatid and in the mature spermatozoon. At the end of the differentiation, centrioles and microtubules lie parallel to the spermatid axis. The disto-proximal centriolar rotation is proposed as a synapomorphy for the Rhabdocoela. The modifications of the intercentriolar body during spermiogenesis and the migration of the nucleus and the centrioles towards the cytoplasmic distal projection are also described. The mature spermatozoon of M. viaregginum is filiform and tapered at both ends and presents many features found in the Rhabdocoela gametes. The nucleus disappears before the flagellar insertion and a density gradient of mitochondria is observed along the sperm axis. The anterior end of the spermatozoon of M. viaregginum is characterised by a tapering capped by a membrane expansion. This study has enabled us to describe precisely the orientation of spermatozoa in the Rhabdocoela in general: the centriolar extremity is proposed as the anterior one for the Rhabdocoela.

Culioli, J.-L., Foata, J., Mori, C., Orsini, A. and Marchand, B. 2004. Ultrastruc- ture of spermiogenesis and the spermatozoon in Castrada cristatispina Papi, 1951 (Platyhelminthes, Rhabdocoela, Typhloplanida). — Acta Zoologica (Stockholm) 85 : 245-256 Spermiogenesis in Castrada cristatispina begins with the formation of a zone of differentiation containing two centrioles with associated striated rootlets and an intercentriolar body between them. The centrioles give rise to two parallel, free flagella of the Trepaxonemata 9 + '1' pattern, growing out in opposite directions. Spermatids undergo a latero-ventral rotation of the flagella and a subsequent disto-proximal rotation of centrioles, and a distal cytoplasmic projection appears. The former rotation involves the compression of a row of microtubules and allows the recognition of a ventral side and a dorsal side. At the end of the differentiation, the centrioles and cortical microtubules lie parallel to the sperm axis. The modifications of the intercentriolar body and the migration of the nucleus and the centrioles toward the distal projection are described. The mature spermatozoon of C. cristatispina is filiform, tapered at both ends and shares several features with the other Rhabdocoela gametes. Nevertheless, the posterior extremity is capped by an electron-dense material. A gradient between mitochondria and dense bodies exists along the sperm axis. This study has enable us a phylogenetic approach of the Rhabdocoela through a comparison of the ultrastructural features of C. cristatispina with the other Rhabdocoela taxa. We propose the disto-proximal rotation of centrioles as a synapomorphy of the Rhabdocoela.

The distribution of arsenic and antimony discharges related to a past mining activity in the Bravona River and its tributary, the Presa River, was investigated. We determined levels of arsenic and antimony in the water and the biota (bryophytes, benthic macroinvertebrates and fish), along a pollution gradient. Concentrations of metalloids downstream mining wastes were significantly higher than those in reference station sites. The pattern of accumulation of arsenic in the food chain decreased as follows: macroinvertebrates > bryophytes > water > fish tissues. For antimony, the lowest concentrations were found in water. The accumulation of metals in invertebrate taxa depends on their place in the food chain, their feeding behavior, and their specific habit (lenitophilic/rheophilic species). Concentrations of both metalloids decreased with increasing trophic level.

The impact of arsenic (As) discharge related to a past mining activity in the Bravona River and its tributary, the Presa River, was investigated in an edible fish, the brown trout (Salmo trutta). Fish was sampled in four stations along a contamination gradient. Arsenic was measured in five organs type (operculum, gills, liver, muscle, and axial skeleton). Almost 70 years after the suspension of the mining activity, As levels in water remain high. The results indicated a strong As contamination in fish collected downstream from the mine. The operculum, liver, and gills showed the highest As concentrations whereas levels in muscle were lower. A strong positive correlation between As concentrations in water and in tissues was observed. Bioaccumulation occurred preferentially in the gills, operculum, and liver. Since As levels in tissues of S. trutta followed the pollution gradient, this species appears useful as biomonitor for metalloid accumulation.

Knowledge of the Branchiopoda of Corsica is limited. Their distribution is updated, on the basis of eight years of investigations on 20 ponds. To date, three species of Anostraca and one species of Notostraca have been reported (Tanymastix stagnalis, Chirocephalus salinus, Branchipus schaefferi and Triops cancriformis cancriformis). B. schaefferi (recorded for the first time in Corsica) occurs in a single locality, C. salinus and T. cancriformis cancriformis are limited to restricted distributions, while T. stagnalis is common in temporary ponds of Corsica. Their status is assessed according to IUCN Red List criteria. Temporary habitats are endangered by human activities and require a proper conservation management.

International audience; The present paper describes the ultrastructure of spermiogenesis and the spermatozoon of Macracanthorhynchus hirudinaceus, an acanthocephalan parasite of the wild boar Sus scrofa. At the beginning of spermatogenesis, spermatocytes exhibit synaptonemal complexes and 2 centrioles. In the spermatid, only 1 centriole remains, generating a flagellum with a 9+2 pattern. Another ultrastructural feature observed during the spermiogenesis of M. hirudinaceus is the condensation of the chromatin, forming a "honeycomb" structure in the old spermatid and a homogeneous, electron-dense structure in the spermatozoon. The mature spermatozoon of M. hirudinaceus presents a reversed anatomy, as has been described previously in other species of the Acanthocephala. The spermatozoon is divided into 2 parts: an axoneme, and a nucleocytoplasmic derivative. The spermatozoon flagellum exhibits a 9+2 or 9+0 pattern. The process of spermiogenesis and the ultrastructural organization of the spermatozoon of M. hirudinaceus are compared with available data regarding other acanthocephalan species.