Website policy

Taxonomy

The taxonomic focus of this website is to maximise coral taxonomic accuracy and certainty whilst allowing for changes that stem from new studies and further information. The use of International Commission of Zoological Nomenclature (ICZN) regulations awaiting revision, artefacts of history and Latin declension as reasons for changing established nomenclature are not supported by this website. Results from molecular studies are supported where they provide new information that is not overtly in conflict with morphology. The website makes note of differing opinions of others where specialist knowledge is involved.

ICZN regulations or the use of them by several recent taxonomists have departed, in some cases drastically, from the axiom that nomenclatural changes should only be made if they increase certainty. An extreme example is the replacement of the genus Favia, used unambiguously in thousands of publications, with the previously unused genus Dipsastraea because of a mistake made over a century ago in designating a type species. In total, the validity of nineteen well established genera lack certainty for similar historical reasons. It is the policy of this website to retain widely recognised generic names unless there is a compelling biological reason for changing them. See Overview of coral taxonomy and The potential of type species to destabilise the taxonomy of zooxanthellate Scleractinia for further detail. Similarly, species names involving an unresolved issue over type specimens are retained if their usage is unambiguous, but not in cases where there is a clearly defined mistake.

Synonymies

Original taxonomic study of most corals requires a high degree of familiarity with species in both field and laboratory. Only after that familiarity has been achieved can the taxonomist work meaningfully with historical collections normally found in museums. Work on museum specimens without prior field knowledge has been the biggest single source of error in the history of coral taxonomy, see Overview of coral taxonomy for further information. For this reason, this website places reliance on field delineation of species ahead of museum-based studies and the nomenclature derived from such studies. A synonymy of names and the use of those names is provided in the Taxon Finder tool. Users should consult original publications including references provided in the Species factsheets for details of the use of names by individual authors.

Molecular studies

Results from molecular studies have been incorporated into the taxonomic framework of this website where they are not in overt conflict with morphology. Where such conflict exists, for example the inclusion of Psammocora explanulata van der Horst, 1922 and Coscinaraea wellsi Veron and Pichon, 1980 in the genus Cycloseris by Benzoni, Arrigoni, Stefani et al. (2012), names have not been changed. The issue is not with the molecular study itself but with the sometimes questionable ability of molecular techniques to reveal phylogeny. This website takes a conservative approach to such issues with the intention of making changes once the case for change has been well established.

Taxonomic comprehensiveness

Nomenclature included in the Taxon Finder tool of this website is intended to be comprehensive for all species names in use after 1980. The inclusion of names and synonyms from literature prior to 1980 is dependent on their relevance to the taxonomy or distribution records of species that are recognised as accepted on this website.

Taxa

Species and genus names given in this website are indicators of taxonomic status - some are arbitrary and/or await further study. Species are thus presented as operational taxonomic units rather than genetically isolated units. They may therefore have fuzzy taxonomic, morphological, genetic, ecological and distribution boundaries.

Distribution maps

Distribution maps are presented for accepted species. The construction of these maps is a complex task made so because of taxonomic issues and the range, quantity and quality of published information and other data sources. This website combines ecoregion-based data with species-specific data, both of which have variable levels of reliability, see Methodology and data limitations. All maps should be viewed as a hypothesis, one well-grounded in detail yet containing significant areas of doubt. Maps are currently limited to ecoregions, these being the finest comprehensive units currently available.

For some ecoregions most or all records come from original fieldwork by the authors and colleagues, for others most come from publications, both recent and historic, and predictions, see above and Overview of coral distributions.

Website policy is to represent as closely as possible the true distribution of the species in the view of the authors. This is a complex assessment of the likelihood of misidentification of closely related, similar or cryptic species, the confirmed presence of the species in neighbouring regions, availability of suitable habitat and a number of other considerations. Where there is significant doubt the records are classed as doubtful, awaiting further confirmation.

Ecoregions

Distribution data is presented as presence/absence at the level of ecoregions at the present time. In all cases, ecoregions are delineated with a view to retaining a meaningful level of internal consistency while retaining external distinctions from neighbouring ecoregions. In some cases where ecoregions share a common boundary the delineation may be arbitrary. Users should be aware that the time and effort taken to accumulate these data, especially for Indonesia and other countries of the Coral Triangle, has meant that some ecoregions now have little or no external distinction from their neighbours. At the other extreme some ecoregions clearly warrant subdividing. These subdivisions will be made when the level of occurrence data is sufficiently comprehensive to allow this to be done, see Ecoregion Factsheets.

Distribution analyses

Our Overview of coral distributions is based on data collected and analysed prior to 2016 and will therefore change with future data additions. Website policy is to provide revisions to this publication only when these additions are widespread and substantial.