Why does taxonomy matter in 2014?

Lean este artículo en español.

In the immortal words of Joni Mitchell “Don’t it always seem to go. That you don’t know what you’ve got ‘til it’s gone”. This otherwise practical guideline for life is particularly poignant when it comes to the topic of biodiversity on planet Earth. The inconvenient irony is that we may never know what we had even after it has gone… extinct. Understanding the richness of life on Earth is dependent on the science of taxonomy that aims to reliably classify organisms into units based on shared characteristics (morphological and molecular), and systematic assignment of distinctive names.

So how does “taxonomy” guarantee a way out of the awkward dilemma of inevitable undocumented loss? Well, the short answer is that it doesn’t. There is no guarantee that even with every scientist, naturalist, science enthusiast and lay person working together around the clock that we could successfully document, catalog and describe every last species on the planet before it meets its end – fatefully (due to natural selection or disasterous meteorite impact or the like) or ill-fatedly (due to human perturbation or neglect). But one thing is certain: without increased efforts of current and aspiring taxonomists we will lose grasp of any hope we have of understanding species richness on land, and in the air and sea. 

Fig. 1. Line drawings of Alatina alata (Reynaud, 1830) reproduced from original illustration by Prêtre in Lesson's 1830 book Centurie Zoologique¹.

Good taxonomic practice involves recognizing a species based on its original description (and molecular barcode data when available), organizing species using a classification informed by historical relationships (phylogenetics), and describing and naming new species (taking into account the code of nomenclatural rules established for plants, animals, or microbes; e.g., ICZN). But when the original description is lacking or inadequate, or the material (those specimens on which the original description was based) has been long-lost, or there is doubt that a specimen was ever collected… what options are taxonomists left with for distinguishing one species from another?

When an old species description is poor and lacking type material, it might be tempting to establish “new species”, right? But repeatedly describing species in this manner does nothing to advance our understanding of overall species diversity. Instead it leaves us with a heap of potential synonyms for the same species and an accumulation of manuscripts spanning decades or even centuries, often written in multiple languages, to go over with a fine tooth comb looking for the first instance of the use of a name that corresponds to the organism under study. And that is exactly what we faced in dealing with one of our organisms targeted for extensive research – a box jellyfish of the genus Alatina.

The so-called winged box jellyfish was originally described one hundred and eighty three years ago as Carybdea alata Reynaud, 1830 in La Centurie Zoologique—a monograph published by René Primevère Lesson¹ (Fig 1) during the age of worldwide scientific exploration.

Reynaud’s brief description gave no details about the collection events or the whereabouts of the specimen, stating only that this box jellyfish “lives in the Atlantic Ocean”. Carybdea alata is the second oldest name for a box jellyfish, and the name has been applied to specimens reported in oceans worldwide (e.g. Pacific, Indian and Atlantic ). In the last decade the species underwent a nomenclatural change being reassigned to the new genus Alatina², but in the absence of a type specimen, i.e., a voucher specimen that represents the originally described species, it has been difficult to confirm which reports actually correspond to the species now known as Alatina alata.

Fig. 2. Alatina alata in situ images from the USNM collections, reproduced from Lewis et al. 2013³.

From 2008 on, working together with collaborators in Bonaire, Dutch Caribbean we collected box jellyfish during several near-shore spawning aggregations. Comparing these specimens with forty six box jellyfish specimens housed in the National Museum of Natural History (USNM) collections from the Western Atlantic, dating as far back as a century, convinced us that all specimens correspond to the species described by Reynaud in 1830 as Carybdea alata. We also discovered archived in situ video and image files in the USNM collections that document the species at 540 m in the Florida Keys and 100 m in the Gulf of Mexico (Fig. 2).  

So why does it matter if we have the right name? It turns out that other species of the genus Alatina have been extensively documented forming monthly spawning aggregations (year round, 8 to 10 days after the full moon in Hawaii ⁴ and Australia ⁵ where they cause painful and debilitating envenomation, negatively impacting tourism. Our redescription of A. alata was conducted with the purpose of stabilizing the identity of A. alata, and by fixing the name to a neotype from Bonaire where fresh material can reliably be obtained we hope to encourage future studies of the Alatina group. Recent studies have shed light on the genetic underpinnings of “stinging cells” (i.e., nematocysts – see Fig 3) in model cnidarians^6–8 but such studies are lacking for box jellyfish species. Alatina is poised to emerge as a key cnidarian model organism, with the mitochondrial genome recently characterized^9,10, and a nuclear genome assembly currently underway (Genbank accession PRJNA167165 and PRJNA41627).

Fig. 3. Cnidome (inventory of nematocysts) of Alatina alata neotype and USNM specimens, reproduced from Lewis et al. 2013³.

Ultimately, if by studying an organism in our own backyard (i.e., in this case a venomous box jellyfish in the Western Atlantic) we can provide information to colleagues on similar or closely related species in disparate localities worldwide, we trust we can foster scientific collaboration while alleviating taxonomic redundancy, and more effectively inventory the species richness of the Earth.

by Cheryl Lewis Ames (Smithsonian Peter Buck Predoctoral Fellow), Bastian Bentlage, and Allen G. Collins

Editor's note: This post was edited to remove the use of Comic Sans. I had no idea it could illicit such strong feelings. 

Works Cited:

1.        Lesson RP (Ed.) Centurie Zoologique. Levrault, Paris Fr. 1830:244.

2.        Gershwin L. Carybdea alata auct. and Manokia stiasnyi, reclassification to a new family with description of a new genus and two new species. Mem Queensl Museum. 2005;51(2):501–523.

3.        Lewis C, Bentlage B, Yanagihara A, Gillan W, Van Blerk J, Keil D, Bely AE, Collins AG. Redescription of Alatina alata (Reynaud, 1830) (Cnidaria: Cubozoa) from Bonaire, Dutch Caribbean. 2013;3737(4):473–487.

4.        Chiaverano LM, Holland BS, Crow GL, Blair L, Yanagihara A. Long-term fluctuations in circalunar Beach aggregations of the box jellyfish Alatina moseri in Hawaii, with links to environmental variability. PLoS One. 2013;8(10):e77039. doi:10.1371/journal.pone.0077039.

5.        Carrette T, Straehler-Pohl I, Seymour J. Early Life History of Alatina cf. moseri Populations from Australia and Hawaii with Implications for Taxonomy (Cubozoa: Carybdeida, Alatinidae). PLoS One. 2014;9(1):e84377. doi:10.1371/journal.pone.0084377.

6.        Ozbek S. The cnidarian nematocyst: a miniature extracellular matrix within a secretory vesicle. Protoplasma. 2011;248(4):635–40. doi:10.1007/s00709-010-0219-4.

7.        Zenkert C, Takahashi T, Diesner M-O, Özbek S. Morphological and Molecular Analysis of the Nematostella vectensis Cnidom. PLoS One. 2011;6(7):e22725. doi:10.1371/journal.pone.0022725.

8.        Houliston E, Momose T, Manuel M. Clytia hemisphaerica: a jellyfish cousin joins the laboratory. Trends Genet. 2010;26(4):159–67. doi:10.1016/j.tig.2010.01.008.

9.        Smith DR, Kayal E, Yanagihara A a, Collins AG, Pirro S, Keeling PJ. First complete mitochondrial genome sequence from a box jellyfish reveals a highly fragmented linear architecture and insights into telomere evolution. Genome Biol Evol. 2012;4(1):52–8. doi:10.1093/gbe/evr127.

10.      Kayal E, Bentlage B, Collins AG, Kayal M, Pirro S, Lavrov D V. Evolution of linear mitochondrial genomes in medusozoan cnidarians. Genome Biol Evol. 2012;4(1):1–12. doi:10.1093/gbe/evr123.