- Volume 55, Issue 6, 2005

Bodonid flagellates (class Kinetoplastea) are abundant, free-living protozoa in freshwater, soil and marine habitats, with undersampled global biodiversity. To investigate overall bodonid diversity, kinetoplastid-specific PCR primers were used to amplify and sequence 18S rRNA genes from DNA extracted from 16 diverse environmental samples; of 39 different kinetoplastid sequences, 35 belong to the subclass Metakinetoplastina, where most group with the genus Neobodo or the species Bodo saltans, whilst four group with the subclass Prokinetoplastina (Ichthyobodo). To study divergence between freshwater and marine members of the genus Neobodo, 26 new Neobodo designis strains were cultured and their 18S rRNA genes were sequenced. It is shown that the morphospecies N. designis is a remarkably ancient species complex with a major marine clade nested among older freshwater clades, suggesting that these lineages were constrained physiologically from moving between these environments for most of their long history. Other major bodonid clades show less-deep separation between marine and freshwater strains, but have extensive genetic diversity within all lineages and an apparently biogeographically distinct distribution of B. saltans subclades. Clade-specific 18S rRNA gene primers were used for two N. designis subclades to test their global distribution and genetic diversity. The non-overlap between environmental DNA sequences and those from cultures suggests that there are hundreds, possibly thousands, of different rRNA gene sequences of free-living bodonids globally.

To celebrate the 25th anniversary of the publication of the Approved Lists of Bacterial Names in 1980, the surviving editor Peter Sneath reflects on the conception, preparation and publication of this seminal document in the nomenclature of not just prokaryotes but all organisms.