Taxonomy is more important than ever

coral
Tunicates hidden among corals.                    @Tal Gordon

Taxonomy is more important than ever. Untrained and poorly trained taxonomists can be a real and serious threat that undermines our ability to identify new species, protect rare and endangered species, and correctly identify introduced alien species.

Earlier this summer, I joined students from several countries on a trip to Panama to be trained by Rosana Rocha and Gretchen Lambert in the taxonomic identification of sessile tunicates (ascidians). Ascidians are marine animals belonging to the phylum Chordata, subphylum Tunicata. They are plankton feeders characterised by a sac-like body inside a type of cellulose coat called a tunic.

In a mission to train future generations of taxonomists, the Smithsonian Tropical Research Institute has been offering a series of courses at their Bocas del Toro Research Station in Panama. The high local marine (and terrestrial) biodiversity makes Panama an ideal place to collect specimens for taxonomic studies and training.

Though it was tempting to simply swim in the warm Caribbean waters all day long, the course offered a unique opportunity to observe and collect tunicates in nature among the corals and mangrove roots. All the specimens that we collected from the field were later preserved and used for dissections.

The training was very involved. For instance, high levels of concentration and fine muscle coordination were needed to position delicate internal structures under the stereomicroscope using curved forceps with fine tips. A single specimen typically might take one to two hours of examination and consultation with taxonomic keys and original descriptions before a species name could be assigned.

Taxonomy is hard to do. Misidentifications were far more common than desired. Even with much guidance during the dissections, Rosana and Gretchen would often ask us to try again after reviewing our work. Sometimes, you would find a determined student doing dissections late at night.

However, there was always the possibility that we were examining a yet un‑described species new to science, or a newly introduced species from a different region of the world (and hence not included in regional taxonomic keys for the Caribbean or even for the Atlantic Ocean). At the end of the two-week course, we all became much more proficient tunicate taxonomists.

Without trained taxonomists, newly introduced alien species could be mistaken as a new species to science (only to be synonymised after extensive taxonomic reviews). Even worse, they could be misidentified as native species.

In fact, this was the case for a tunicate specimen collected from Îles-de-la-Madeleine (Québec), which was initially misidentified as a native species. Later, this Canadian specimen was re-examined by Gretchen, only to be eastern Canada’s first record of the non-native species, Diplosoma listerianum (Ma et al. 2016). Had a taxonomist not revisited the specimen, it would have remained misidentified and the significance of its presence would not have been recognized.

mangrove
Tunicates and other fouling species on mangrove roots.           @Tal Gordon

Kevin Ma is a PhD Candidate at Université Laval and a member of Québec-Océan. His participation in the tunicate taxonomy course in Panama was financially supported by Québec-Océan and the Smithsonian Tropical Research Institute.

References: Ma KCK, Simard N, Stewart-Clark SE, Bernier RY, Nadeau M, Willis J. 2016. Early detection of the non‑indigenous colonial ascidian Diplosoma listerianum in eastern Canada and its implications for monitoring. Management of Biological Invasions 7 (4): 365–374.

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