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Nephrops norvegicus (L.) from fishing grounds on the west coast of Scotland has been found to harbour infection by a species of parasitic dinoflagellate. Chromosome morphology and ultrastructural features suggest that the parasite is a member of the botanical order Syndiniales, possibly related to Hematodinium perezi Chatton & Poisson 1931. Cells invading the haemal spaces, however, show no signs of flagella. Mode of transmission IS not yet known, and a flagellate spore stage has not been identified. Infection appears to be fatal to its host, the main cause of death possibly being disruption of gas transport and tissue anoxia caused by the proliferation of large numbers of dinoflagellate cells in the haemolymph. Severe infection has an adverse effect on meat quality that has provoked comment from fisherman and processors. Affected lobsters have been found at all west coast sites surveyed, with peak infection rates reaching 70 % of trawled samples. Infection occurrence shows marked seasonality coincident with the annual moult perlod of N. norvegicus. An increased prevalence of infection has been observed recently in some areas.

Given their ecological and medical importance, the classification of the kinetoplastid protists (class Kinetoplastea) has attracted much scientific attention for a long time. Morphology-based taxonomic schemes distinguished two major kinetoplastid groups: the strictly parasitic, uniflagellate trypanosomatids and the biflagellate bodonids. Molecular phylogenetic analyses based on 18S rRNA sequence comparison suggested that the trypanosomatids emerged from within the bodonids. However, these analyses revealed a huge evolutionary distance between the kinetoplastids and their closest relatives (euglenids and diplonemids) that makes very difficult the correct inference of the phylogenetic relationships between the different kinetoplastid groups. Using direct PCR amplification of 18S rRNA genes from hydrothermal vent samples, several new kinetoplastid-like sequences have been reported recently. Three of them emerge robustly at the base of the kinetoplastids, breaking the long branch leading to the euglenids and diplonemids. One of these sequences belongs to a close relative of Ichthyobodo necator (a fish parasite) and of the 'Perkinsiella amoebae'-like endosymbiont of Neoparamoeba spp. amoebae. The authors have studied the reliability of their basal position and used all these slow-evolving basal-emerging sequences as a close outgroup to analyse the phylogeny of the apical kinetoplastids. They thus find a much more stable and resolved kinetoplastid phylogeny, which supports the monophyly of groups that very often emerged as polyphyletic in the trees rooted using the traditional, distant outgroup sequences. A new classification of the class Kinetoplastea is proposed based on the results of the phylogenetic analysis presented. This class is now subdivided into two new subclasses, Prokinetoplastina (accommodating the basal species I. necator and 'Perkinsiella amoebae') and Metakinetoplastina (containing the Trypanosomatida together with three additional new orders: Eubodonida, Parabodonida and Neobodonida). The classification of the species formerly included in the genus Bodo is also revised, with the amendment of this genus and the genus Parabodo and the creation of a new genus, Neobodo.

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