Fine Structure of Trichomitus batrachorum (Perty)*

SYNOPSIS. Trichomitus batrachorum (Perty) shares with Trichomonadinae most of its fine-structural characteristics, especially those pertaining to the undulating membrane that consists of a high body fold, enclosing the loop-shaped, periodic marginal lamella, and of the recurrent flagellum applied to the fold. This flagellate has also certain structures, i.e. the costal base, comb-like organelle, and well developed marginal lamella, in common with Monocercomonas. It shares with Hypotrichomonas the costal base; large pelta; very fine fibers perpendicular to, and connecting the axostylar microtubules; structural details of the most proximal segment of the marginal lamella; and general relationships between dorsal body fold (poorly developed in Hypotrichomonas) and the recurrent flagellum. All these electronmicroscopic findings support the crucial position of Trichomitus in the evolutionary sequence Monocercomonas→Hypotrichomonas→Trichomitus→ Trichomonadinae suggested previously by lightmicroscopic observations. Further, Trichomitus shares with all Tritrichomonadinae the comb-like structure, not found either in Hypotrichomonas or Trichomonadinae; and it has in common with Tritrichomonas also the costa with Type A periodicity, being the only member of Trichomonadinae with this type of supporting organelle. It appears, therefore, that Trichomitus-type organisms represent an important link in the evolution of all Trichomonadidae from Monocercomonadidae.     

An electrophoretic and morphological study of three Ecdyonurus species (Ephemeroptera: Heptageniidae) occurring in the British Isles

Abstract The objective was to investigate the validity of three closely-related British species: Ecdyonurus dispar, E. venosus and E. torrentis . The species were characterized by eleven enzyme-substrates and fifteen different enzyme-loci, comparisons being made not only between species but also between five populations of E.dispar (three from Britain, one from France, one from Switzerland), two populations of E.venosus and two populations of E. torrentis (one from Britain, one from Switzerland for both species).
Four monomorph enzyme-loci (aldolase, mannose phosphate isomerase, arginine phosphokinase, glutamate-oxaloacetate transaminase-2) exhibited interspecific differences in their mobilities and therefore validated the conclusion that E. dispar, E. venosus and E. torrentis are distinct species. There were no monomorph enzyme-loci that were different between populations of the same species. There were, however, some intraspecific differences revealed by the presence of polymorphic enzyme-loci: seven in E.dispar (retinol dehydrogenase, hexokinase-1 and 2, glutamate-oxaloacetate transaminase-!, malate dehydrogenase-1, phospho-glucomutase, indophenol oxidase-2), three in E. venosus (glutamate-oxaloacetate transaminase-1, malate dehydrogenase-1, phospho-glucomutase) and three in E. torrentis (hexokinase-1, glutamate-oxaloacetate transaminase-1, malate dehydrogenase-1).
The morphological characters of larvae and adults were examined and some were used in new keys to larvae and adults.     

Microsatellites from clade B Symbiodinium spp. specialized for Caribbean corals in the genus Madracis

In order to determine boundaries of genetic recombination among putative ‘species’ of endosymbiotic dinoflagellates, nine polymorphic microsatellite loci were developed and optimized for clade B Symbiodinium designated as type 7 (B7) and two related types, B13 and B13a. Together, they form a subclade in clade B that is specific to Caribbean corals in the genus Madracis. A total of 52 samples were analysed (including 43 B7, 2 B13, 7 B13a) originating from seven Caribbean locations. Diversity indices at each haploid locus ranged from 0.302 to 0.836 and four to 14 alleles were found per locus. The loci were preliminarily cross‐tested on closely related ‘ancestral’ B1 populations found in maze coral Meandrina meandrites and that of another host specialist, B5, from the lesser starlet coral Siderastrea radians.     

MOLECULAR PHYLOGENY AND THE GEOGRAPHIC ORIGIN OF HALIOTIDAE TRACED BY HAEMOCYANIN SEQUENCES

Phylogenetic relationships of 12 species of the vetigastropodfamily Haliotidae were analysed on the basis of partial haemocyanincoding genes. Both protein-coding and genomic sequence data,of which the latter includes one ancient intron, were analysed.We were able to distinguish two genetically different monophyleticgroups with high bootstrap support: (i) the abalones from Europe,South Africa, Australia, Taiwan and Japan group together andare separated from (ii) five California and two Japanese abalones.The usefulness of haemocyanin as a phylogenetic character andthe origin of the Haliotidae are discussed. (Received 4 March 2005; accepted 4 July 2005)