Riddle me this:
How can a millipede be slow-moving and Swift?
Nannaria swiftae, new species, male holotype in situ, Van Buren County, Tennessee. By permission of Derek A. Hennen.
Species discoveries rarely get noticed in our culture. How many of the approximately 20,000 species named last year did you hear about? I rest my case. This is why I urge taxonomists to engage in shameless self-promotion, including naming species after famous people. Celebrity names are simply irresistible bait to reporters. A recent example is a little millipede, Nannaria swiftae, named for, you guessed it, the performing artist Taylor Swift. It has had a fantastic run in the popular press, from NPR to the New York Post and Rolling Stone. And now I’m piling on, too.
The ending of the specific epithet, -ae, is used in zoological nomenclature to indicate a patronym honoring a woman. Under the category of unintended consequences, I wonder if people, a couple hundred years from now when other artists dominate the charts, will find humor in its pronunciation; irony that one of these gentle, slow-moving creatures has a name that, when said out loud, becomes the oxymoron “swifty.”
The genus Nannaria includes small millipedes, about 15 to 38 mm long, found in eastern North America, from Arkansas and Missouri to northern Mississippi, central North Carolina, and New York state, with the greatest concentration of species in the Appalachian Mountains.
As an aside, I grew up hearing Appalachia as the pronunciation for this mountainous region. With little thought, actually no thought, for years I parroted the pronunciation like the Yankee I am. Those born to the region say Appalachia, and history and etymology are on their side, not we northerners. The name originated with the same 16th-century Spanish explorers who named the Apalachicola River and the Apalachee people, native to the Florida panhandle at the head of the Apalachee Bay. So, there is every reason to believe they, too, would have said Appalachia. When I am consciously aware of my words, I try to say Appalachian mountains out of respect for those who call them home.
These little millipedes are brown to black in color, with a bimaculate pattern of orange, red or white spots or stripes. Their diminutive size and burrowing habits make them more challenging to find than many other millipedes. Still, more than sixty species have been named between Nannaria and the related genus Oenomaea.
Raking leaf litter and digging at and below the litter-soil interface on the floor of deciduous forests to find these millipedes, Derek Hennen and colleagues at the Virginia Polytechnic Institute and State University collected several hundred specimens that, combined with museum material, became part of a study set of more than 1800 specimens. The scientists named 17 new species, increasing the number in the wilsoni species-group from 7 to 14, and the total number of species in the family Xystodesmidae to 539.
Shortly after I arrived at Cornell as a young professor, I received an unexpected late-night telephone call. A voice blurted out, “Do you believe that all characters of species are adaptive?” The caller turned out to be Will Provine, the prominent historian of science and leading scholar of population genetics. His thesis was that your answer depended on the lab you worked in as a student. My answer was “No, of course not,” but at the time there were many “evolutionary” taxonomists who believed in panadaptation. Stated another way, they saw two categories of species: those for whom the adaptative significance characters are known, and those with characters whose adaptations we have not yet figured out.
Some groups, including certain millipedes, appear to be prime examples of non-adaptive radiation. Their populations were simply geographically divided. Flightless, and isolated long enough for them to diverge and attain species status, adaptations played no particular role in their origins. The Appalachian Mountains are home to quite a few arthropod groups for which this appears to be the case. Groups with many closely related species whose fragmented distributions are lingering evidence of the complex physiographic history of the region.
The new species Nannaria swiftae is known from three counties in Tennessee at elevations from about 480 to 1500 meters. With few exceptions, data shows that this and related species are found in mesic deciduous forests and rhododendron coves in the Appalachian Mountains. It is a virtual certainty that more species await discovery in poorly collected areas of Georgia, Tennessee, Kentucky, and West Virginia. A woolly adelgid pest, introduced to the United States, has been devastating to hemlock, killing more than 90% of trees in infested stands. When this happens, formerly shady, cool, moist microhabitats beneath the canopy are replaced by drier conditions unfavorable to these millipedes. A condition called rhododendron die back is of concern to Rhododendron maximum that occurs widely in the Appalachians. Were these threats not enough, a fungus pathogen specific to millipedes is known to infect Nannaria species. In spite of limited knowledge of these millipedes’ natural history, their limited geographic ranges make it clear that there is a short path for them from habitat destruction to extinction. Beyond invasive species and disease, land development may be destroying additional species before they have even been discovered.
Who cares if we lose a few millipedes so small and secretive that no one has ever seen one before now? I care. And you should, too. Nannaria have important things to teach us about their natural history and evolution, if we are curious enough to learn. As one example, many species in the family Xystodesmidae have aposematic mimicry, using bright colors — yellows, oranges, and reds on black — to advertise toxic chemical defenses of hydrogen cyanide and benzaldehyde. Nannaria is an exception, however. It has the biochemistry, but does not seem to use it as a primary form of defense. Why has yet to be worked out.
As the biodiversity crisis worsens, we will increasingly find ourselves in the position of deciding which species live or die, whether to destroy a habitat to meet our own needs, or cede it to the species who live there so that they may continue to meet theirs. We cannot save all species, of course. But we can reduce the number lost dramatically, if we so choose. And we can honor all species by preserving evidence that they exist or existed: specimens in museums and recorded observations open the world’s living species to us and assure that we can continue to learn from the extinct. When we don’t know species, when they are mere statistics, it is much easier to accept their demise. But looking at a species face to face, calling it by name, knowing the attributes that make it unique makes callous indifference difficult.
It is obvious that permitting species to go extinct threatens the integrity and stability of ecosystems, and creates irreparable gaps in our knowledge of evolutionary history. Letting them die-off unknown and unsung carries yet another risk. When we ignore what is happening, or ask “Why name a species that will soon be extinct anyway?,” knowingly allowing species to go extinct without so much as bothering to learn that they ever existed, we lose a little piece of our humanity, too.
If you are feeling philosophical, contemplating the ethics of our relationship to biodiversity and whether it is worth taking steps to assure that a small, obscure animal like Nannaria swiftae survives, I recommend that you look for the answer in a most unlikely place: the lyrics of Taylor Swift’s Stay, stay, stay: As she said in the song, “I think it’s best if we both stay.”
Acknowledgment
I thank Derek Hennan for permission to reproduce the photograph of Nannaria swiftae.
Further Reading
Hennan, D. A., Means, J. C., and Paul E. Marek (2022) A revision of the wilsoni species group in the millipede genus Nannaria Chamberlin, 1918 (Diplopoda, Polydesmida, Xystodesmidae). ZooKeys 1096: 17-118.
Puckett, Anita (2000) On the pronunciation of Appalachia. Now & Then: The Appalachian Magazine 17: 25-29.