Taxonomy and Systematics

Taxonomy (describing, delimiting and naming organism) and systematics (reconstructing and interpreting the evolutionary interrelationships between organisms) are fundamental in that they provide the framework for all comparative studies in biological sciences.

Professor David Bilton use aquatic insects, particularly water beetles, to explore fundamental and applied topics in ecology, evolution and conservation. With more than 12,000 described species, water beetles are abundant, diverse and ecologically important organisms in almost all non-marine aquatic habitats, from water-filled tree holes to large lakes and rivers and on all continents except Antarctica. Their wide geographical and ecological range, together with their diversity, makes them ideal model organisms for studying biogeography and the evolution of sexual conflict, themes explored in our recent review (Bilton et al. 2019). Water beetles are also excellent surrogates of wider aquatic biodiversity and we have developed their use as indicators for ecological and conservation assessment. Prof Bilton’s work on the taxonomy and systematics of aquatic beetles underpins these studies and includes the production of identification guides and atlases summarising the ecology and distribution of individual taxa to understand what an organism is, and what it does. Only by focussing on species-level data can we reasonably detect anthropogenic impacts on aquatic ecosystems in their early stages.

The taxonomy and systematics of the Bacteria are largely undertaken using a mixture of classical chemotaxonomic and biochemical markers as well as recently-developed bioinformatic methods. Dr Rich Boden’s group has made extensive study of the sulfur-oxidising Bacteria from environments as diverse as sewage, deep-sea hydrothermal vents, agricultural soils, and the Roman thermal spring at Bath. We have made a number of reclassifications of extant taxa as well as discovering new species and thus far have named novel species, genera, families, orders and classes in the phylum “Proteobacteria”, with particular focus on the genera Thiobacillus and Sulfuritortus, and four gener we have named (Annwoodia, Thiomicrorhabdus, Thiofilum and Thiolinea) (see Boden & Hutt 2019, 2020). Through this work, we have also undertaken a comprehensive assessment of the Betaproteobacteria, dividing it to create the new class Hydrogenophilalia and creating several novel families in the order Nitrosomonadale. Through this, we further developed the use of ribosomal protein concatemer analysis in bacterial phylogenetics and systematics and furthered previous work on establishing new 16S rRNA gene cut-offs for the ranks of genus up to class.

With over 8200 described species but about a third in decline or disappeared, Amphibians are the most endangered class of vertebrates. Dr Rob Puschendorf’s interest in conserving and rescuing critically endangered amphibians has led him to reassess the status of several species. Cryptic diversity is common among amphibian species and without knowing which species occur where, it is of course impossible to protect and conserve endangered populations (see Puschendorf et al 2019).

Selected Publications

Aquatic Insects

Foster GN, Bilton DT, et al (2020) Atlas of Water Beetles of Britain and Ireland – Smaller Families of Polyphaga. Field Studies Council. 1-296.

Blair J & Bilton DT (2020) The call of the squeak beetle: bioacoustics of Hygrobia hermanni (Fabricius, 1775) revisited (Coleoptera: Hygrobiidae). Aquatic Insects 41: 131-144.

Bilton DT, et al (2019) Water beetles as models in ecology and evolution. Annual Review of Entomology 64: 359-377.

Vasilikopoulos A, (Incl. Bilton DT) et al (2019) Phylogenomics of the superfamily Dytiscoidea (Coleoptera: Adephaga) with an empirical evaluation of phylogenetic conflict and systematic error. Molecular Phylogenetics and Evolution 135: 270-285.

Bacteria

Boden R, Hutt LP (2020) Acidithiobacillus. In: Bergey’s Manual of Systematics of Archaea and Bacteria.

(see also BMSAB for 2019 Boden group papers on Methylophaga, Thiobacillus, Thermithiobacillus, Annwoodia, Sulfuritortus and Hydrogenophilalia)

Boden R, Scott KM (2018). Evaluation of the genus Thiothrix Winogradsky 1888 (Approved Lists 1980) emend. Aruga et al. 2002: reclassification of Thiothrix disciformis to Thiolinea disciformis gen. nov., comb. nov., and of Thiothrix flexilis to Thiofilum flexile gen. nov., comb nov., with emended description of Thiothrix. International Journal of Systematic and Evolutionary Microbiology 68: 2226-2239.

Amphibians

Puschendorf R, ….(Incl Knight ME) et al (2019) Cryptic diversity and ranavirus infection of a critically endangered Neotropical frog before and after population collapse' Animal Conservation 22: 515-524.

Funding

Professor David Bilton (PI fellowship with Dr Susana Pallares) The evolution of salinity tolerance in aquatic Coleoptera. Fundación Seneca Fellowship €96,000. July 2019-June 2021.

Professor David Bilton (PI) The conservation biology of Europe’s most threatened water beetles. Mohammed bin Zayed Conservation Fund £8,200. 2016-2021.