INTRODUCTION Use of DNA data in determining phylogenetic relationships is well established. DNA barcode approach to use a small section of DNA as a species identifier has caused much controversy. Much of this centres on cases in which DNA barcode region has failed to identify “established species”. In biology, no method is 100% accurate, so such examples are over-emphasised by some.

MORE IMPORTANT ISSUES Should barcode approach be largely aimed at: making it easier to identify described species; identifying new biodiversity; a combination of the two? Can barcoding speed up identification of new species? How useful is a DNA barcode if it is not linked to a morphological description? Can barcoding provide an avenue to encourage new participants into taxonomy? What research areas will benefit most from barcoding?

MORPHO-SPECIES Morpho-taxa are designated on easily recognisable characteristics but not comprehensively compared with other species or formally described. Within a sample, assumption is that morphological sibling species are unlikely to be present. How do we determine whether similar looking morpho- species from different locations are the same or different? DNA barcoding can provide test of conspecificity. Morpho-species approach with DNA barcoding can be used to undertake rapid assessment of new biodiversity.

Bugula dentata

ALPHA TAXONOMY  Will barcoding increase the rate and efficiency of identifying new species?  Current estimates are that 1.7 M species have been described over the past 200 years.  Over 8 M species yet to be discovered or described.  Conventional means are clearly too slow.

ALPHA TAXONOMY Birds are well documented- why? Species diagnoses are relatively simple - plumage patterns, morphology and vocalisations. DNA data has revealed additional species in groups which are: cryptically coloured; widespread e.g. Barn Owls; characterised by many island populations. Nevertheless, for majority of cases DNA data confirms traditional morphological assessments.

ALPHA TAXONOMY (application to invertebrates) What can we learn from bird examples? Morpho-species approach for many invertebrates is the first step in documenting diversity. If DNA barcode data confirms species status of morpho-taxa,, then detailed morphological diagnoses are not critical for species description. Morphological characteristics are then only required for providing a simple method of species identification, rather than species diagnosis.

Watersipora subtorquata Watersipora arcuata

ALPHA TAXONOMY Barcoding provides a rapid assessment without the need for detailed morphological expertise in the first instance. More detailed morphological analyses can be undertaken if one is interested in functional morphology, evolutionary adaptations etc. Rapid confirmation of cryptic species.

Mucropetraliella ellerii minimum spanning network of mutations in COI and sample localities. Photograph by Karen Gowlett-Holmes

TRAINING NEW TAXONOMISTS Assumption is that undertaking taxonomy requires much specialisation. Specialisation is ok if jobs and opportunity exist. Limited opportunity for specialist taxonomists. Train next generation with other skills – macroecology, population biology, genetics etc. Barcoding allows taxonomy without the need for detailed training – more flexibility, ability to work in other areas. Number of specialist taxonomists may be less but number of generalists taxonomists will increase many-fold Hope for taxonomists

LINKING ADULT and JUVENILE/LARVAL FORMS Linking adult and juvenile stages is often difficult in groups such as marine and freshwater invertebrates, fishes, amphibians and terrestrial invertebrates. Important implication for management of fisheries, marine bio-regionalisation, identifying larvae of pest species and monitoring freshwater quality. Better understanding of dispersal patterns of adults and juveniles. Documenting taxonomic diversity need not rely only on adult specimens.

TRACKING LIFE CYCLES OF SPECIES In species with complex life-cycles, especially parasites with multiple hosts, barcoding can be an invaluable tool.

LINKING MALE AND FEMALE MORPHOLOGIES In many Dipteran and Hymenopteran insects, species identity is based on male genital morphology. Female morphology is more conserved and useful at generic alignment but not species identity. Documenting taxonomic diversity need not rely on male specimens only. Better understanding of dispersal of males and females within a species and relative abundances of the sexes.

INVASIVE vs COSMPOLITAN SPECIES A global approach is needed to identify whether a species is widespread in its distribution, or has dispersed through recent human-mediated events. Regional barcoding programs are a key component. Taxonomic approaches rely on knowledge of taxonomic variation, whereas regional ones are not biased by taxonomic perceptions. BOLD database provides the vehicle for researchers to differentiate between cryptic species, cosmopolitan species and invasive species.

CHALLENGES FOR THE FUTURE One of the things that makes barcoding less than palatable to many research organisations and funding bodies is that it lacks hypotheses. This makes it seem less like science and more like engineering.

By alleviating the need for detailed taxonomic expertise, are we in danger of losing the expertise altogether?