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Posted by languagehat

https://languagehat.com/exuviae/

https://languagehat.com/?p=17919

My wife and I always enjoy Bill Danielson’s weekly nature columns in our local paper, the Hampshire Gazette; he usually writes about birds, but this week it was an oddly specialized topic and an unusual word I didn’t remember encountering before:

The word was “exuvia” and those of us that heard it were overcome with a mixture of surprise, confusion and skepticism. The person who dished up this scientific morsel was Brian Adams, professor emeritus of environmental science at Greenfield Community College. The setting for such an utterance was a radio studio at WHMP in Northampton, where I was sitting for an interview with Brian, Bill Newman and Buz Eisenberg on their wonderful “Talk-the-Talk” program on July 23.

Our conversation was centered around a photograph in last week’s paper that featured a fragrant water lily with a spreadwing damselfly clinging to one of the petals on the left-hand side of the photo. I then called everyone’s attention to a yellow “smudge” on the inside surface of the very same petal that was supporting the damselfly. This, I explained, was the shed skin of a damselfly nymph that had crawled out of the water, freed itself from its shell and abandoned it in order to start its adult life. Everyone was looking at the photo and then we heard “exuvia” in our earphones. It was Brian who had offered up the term out of nowhere.

As luck would have it, we were right at the point in our segment where it was time for a commercial break. The microphones went dead and every cellphone and computer in the studio was immediately activated for our combined mission to fact-check this spontaneous utterance. Was Brian a genius, or a complete lunatic? In seconds, the answer to our question was settled: Genius! Bill Newman read the search results and the studio (and the first moments of the second half of our segment) erupted with exuberant, triumphant and congratulatory laughter.

Here is what our search found: “In biology, exuviae (singular: exuvia) refers to the shed exoskeleton or outer covering of an arthropod (like insects, crustaceans, and spiders) after molting. Essentially, it’s the ‘skin’ they leave behind after growing.” Examples of this structure included cicadas and dragonflies. Jackpot! I went on to explain that the photo of the water lily was meant to show the flower, rather than the insects, but it was true that I could have zoomed in on the exuvia to reveal its details. Sometimes, a single photo has so much going on that you need to make a choice. […]

So what we see in today’s photo is the exuvia of a large species of dragonfly. The nymph that may have lived underwater for a couple of years had finally reached a point where it was time to crawl up out of the water, break out of its skin one more time, and take its adult form. It is not clear in this particular photo where the exact location of the split on the nymph’s dorsal surface might be, but the presence of those white “strings” gives a hint. These white structures are called “tracheae”: which are “the internal air tubes that insects use for respiration, essentially their ‘lungs.’” Imagine pulling off your socks and having them turn inside out and you have the right idea.

The photo that showed the details of the exuvia did not show you what the plant itself looked like, so I decided to create a composite image that combined the details of two different photographs. The insert shows the blossoms of the flowering rush (Butomus Umbellatus) that the dragonfly nymph had chosen to climb. I didn’t have room for the plant’s leaves, nor for the shape of the “umbell” formed by the plant’s many flowers, but I think the detail of a single flower was the most interesting. The plant was about 4 feet tall and growing in shallow water. I took these photos on July 25, 2011, and have only just now found an opportunity to use them in tandem.

Naturally, I looked it up in the OED, where it’s under the plural exuviae, “Cast skins, shells, or coverings of animals; any parts of animals which are shed or cast off, whether recent or fossil” (entry from 1894; first cite 1670: “They [insects] divested the habit they had..and appeared with their exuviæ or cast coats under their feet,” R. Boyle, Contin. New Exper. iv, in Works III. 378). This note was added in 1997:

Also in singular in the form exuvium (the reconstructed Latin feminine singular exuvia being reinterpreted as neuter plural), and in plural as exuvia.

Wiktionary has it s.v. exuvia and says:

Back-formation from the plurale tantum exuviae (“the skin of an animal sloughed off”), from exuō (“to take off”). See also exuvium.

And under exuvium we find:

Perhaps from Latin exuvium, or perhaps an independent back-formation from exuvia, under the impression that exuvia is the plural of a Latin second-declension neuter noun exuvium, whereas exuvia is in reality the regularised first-declension singular of Latin exuviae.

Incidentally, today marks the twenty-third anniversary of Languagehat; as always, I am endlessly grateful to all those who frequent these environs and provide the information, jokes, and camaraderie that make it worth keeping the thing going.

https://languagehat.com/exuviae/

https://languagehat.com/?p=17919