A new chloroplast-containing species of the sand-dwelling benthic dinoflagellate Thecadinium was isolated and cultured from a single cell collected from shallow waters of the marine Loch Ewe in North West Scotland. The cultured cells are described by light and scanning electron microscopy and the genetic affinities examined by comparison of ribosomal RNA gene sequences. Thecadinium foveolatum Bolch sp. nov. is heavily armoured with thecal plates that are ornamented with evenly distributed pores and contains numerous globular, dark golden-brown chloroplasts. Cells are broadly ovoid and slightly laterally compressed, with a descending cingulum displaced approximately half of the cell width. The thick thecal plates, numerous pores and the strongly displaced cingulum clearly differentiate this species from the only other chloroplastcontaining species, T. kofoidii, and the remaining non-photosynthetic Thecadinium species described. Analysis of largesubunit rDNA sequences of Thecadinium foveolatum and other members of the Peridiniphycidae indicate that this new species is allied to the gonyaulacalean lineage rather than the peridinialean taxa included in the analyses.

Six samples (n =67 to 154) of blue-eye or deepsea trevalla were collected from south-eastern Australia (seamounts off New South Wales, a seamount south-east of Tasmania called the Cascade Plateau, off the east, south and west coasts of Tasmania, and off the coast of South Australia). All fish were analysed by starch or cellulose acetate electrophoresis for the products of seven polymorphic loci (defined in this study as those with an average heterozygosity greater than 0.06); a minimum of 24 fish per area were also analysed for 29 other less variable loci. The average heterozygosity per locus was 5.3%. Polymorphic loci showed no significant deviations from Hardy-Weinberg equilibrium. The coefficient of genetic subpopulation differentiation, GST, was 0.38%. Bootstrapping procedures showed that this low value could be attributed to sampling error alone. Contingency Χ2 analysis similarly failed to reveal any significant inter-sample differentiation for any locus. The results indicate that gene flow is sufficient to prevent any genetic differentiation among the sampled localities. During the course of the study a second trevalla species, Schedophilus labyrinthicus, was identified in the New South Wales component of the fishery.

The phylogenetic relationships of 11 stromateoid species (nine from the Family Centrolophidae and one each from the Nomeidae and Tetragonuridae) were examined by allozyme electrophoresis. Data from 30 loci were used for three phylogenetic analyses. Two phenetic trees were derived: a UPGMA tree derived from Nei's unbiased genetic distance, and a distance-Wagner tree based on modified Rogers' distances. A cladistic analysis, using maximum parsimony, was also carried out with loci as characters and alleles as unordered states. The tree topology of all three analyses showed a high degree of similarity, which increased confidence in the phylogenetic interpretation and generally supported the classical taxonomic theory of centrolophid relationships. The 'hard-spined' centrolophid taxa, including Seriolella, Psenopsis, Schedophilus labyrinthicus and Hyperoglyphe, formed a stable group In all trees. Psenopsis was closely allied to Seriolella in all three analyses, which supports the view that this genus is derived from Seriolella. Centrolophus and Tubbia consistently diverged from the ancestral line of taxa near the base of the tree, so may have diverged from ancestral stock earlier than previously thought. The most striking departure from current taxonomic theory was the wide separation of Schedophilus labyrinthicus and Schedophilus huttoni, indicating that the genus Schedophilus is polyphyletic. A revision of the genus is needed and should include morphological and electrophoretic analyses of all Schedophilus species, with particular reference to the type species S. medusophagus.

The morphology and genetic affinity of a novel raphidophyte belonging to the genus Chattonella Biecheler is described for the first time from the Oman Sea along the south-east coast of Iran. While morphologically very similar to Chattonella subsalsa Biecheler, the Iranian isolates contain a distinct red eyespot. A comparison of LSU-rDNA and rDNA-ITS show that the Iranian isolate is genetically distinct from other Chattonella subsalsa strains isolated from across a wide global range and indicates that the Iranian isolates represent a distinct species related to Chattonella subsalsa.