Thursday, November 3, 2016

Species species of the Week week #11 OR Shells That Make Adolescents Titter

According to Google search results, there are two types people who are interested in this week's featured tautonymical snail: conchophiles and tittering adolescents(1). The former love the shell, the latter love to say its name and then giggle. I give you:

Volva volva

The Shuttlecock volva
So in your opinion, does this look like a good thing to hit over a net with a racket?
By H. Zell - Own work, CC BY-SA 3.0

I don't know who came up with that common name, but I'm not convinced they ever actually played badminton, or maybe I'm missing the reference. I do know, however, that they certainly would have been popular in a class of tittering 9th graders.

The origin of "volva" is based in movement, "to roll, to wrap around". I make no comment or speculation about the subsequent derivation of anatomical names, but from a descriptive point of view, this tautonym makes quite a bit of sense, if it seems like it could be applied to any number of snails. That mystery solved, I moved on to learn more about the species, but much to my surprise in these things, there appears to be a group of people who are not that interested in this snail: non-taxonomist scientists. There really just isn't much published on this species' ecology, physiology, or whatever else it is other scientists do(2). What I can deduce is the following:
  • Range: Indo-west Pacific (duh, that's where all the beautiful shells come from!)
  • Member of the false cowries (Ovulidae) which are commonly predators or parasites. The name Ovulidae comes from the egg-like appearance of many of the shells in this group.
  • "Associated" with sea whips and sea pens suggesting kleptocnidae (kleptocnidae = stealing tiny harpoons from cnidarians and redeploying in self defense - read my previous post for more)
I think they are also even cooler looking when actually alive and inhabiting their shell (note to self: be sure not to accept suggested respelling of search terms when doing a Google Image search for this species):

What a wonderful candidate for an alien life form. When the snail is living, the mantle (the part the forms the "head" of an octopus) wraps around the shell, and the color and texture varies widely, presumably helping camouflage the snail on its host, though why anyone would want to try to eat this thing is beyond me. Photo:  CalAcademy

So, in the absence of compelling new ecology to tell you about, I dove down a rabbit hole (more tittering, I daresay) when researching this species and trying to pin down the name. I actually first became aware of double Volva when I saw a tweet by Emily Graslie, Chief Curiosity Correspondent at the Field Museum:

Even the monkeys are tittering! But looking at the entry for the species on WoRMS I noticed that the original name given by Linnaeus was actually Bulla volva(3). You might remember Linnaeus as the namer of all things. He is the heartthrob of many a biologist - or maybe I'm just projecting and I'm the only one who swoons when I think of his contribution to science? He's also the bane of most 9th graders, who have to figure out some freaking mnemonic(4) to make the classification system stick in their brains for 35 minutes or until the end of the quiz, whichever comes first. The Systema Naturae truly is a system, a language from which you could divine a great deal of information. Granted it was an early attempt and it seems unfathomable now that echinoderms got smushed into the same group as cnidarians, and, together with actual worms, were lumped into a group called Vermes in the first edition(5).

I digress. OK. So when Linnaeus chose a name for this snail he actually chose the name Bulla volva. Two things happened [to me, obvi] then:

1. I noticed some parentheses.

When you are writing a science-y thing, and you reference the "scientific" name of a species, you are technically supposed to also list the Species Authority(6) after the species name. So, for example, Charles Darwin was the first to describe and name the species of acorn barnacle common to the coasts of the northeast Pacific Ocean, so the name is written Balanus glandula Darwin, 1854. The idea is that this should help distinguish among homonyms and keep track of species for which the names have changed a bunch of times. The listing of Darwin, 1854, is called an author citation. For the shuttlecock volva, it's correctly cited as Volva volva (Linnaeus, 1758). <-- did you notice the parentheses too?! NOT A TYPO!

Now, when you read a lot of academic literature, your brain gets used to ignoring parentheses(7) because they bracket citations, and you only read the info in them if you are going to look up the reference(8). So, I assumed that the use of parentheses in some, but not all, author citations was just a stylistic thing. Turns out, it actually has meaning - so Systema-tic! The cited author, when in parentheses, was not the author of the currently accepted name. Now I will leave it to you to read into details on how it is determined just which lucky person gets cited as the authority(9), but nevertheless, this clarifies our situation with the 2x Volva. Linnaeus originally described it and put it in the genus Bulla, and later it was moved to a genus determined to be in better alignment with the known evolutionary relationships with other species - or whatever. The species formerly known as Bulla volva has been "synonymized" with Volva volva, and in fact so has the subspecies Volva volva volva (I KNOW!).

2. Linnaeus was pretty far off with Bulla, but a lot of others were too. 

I found a LOT of snails that were originally put into that genus that have since been moved. It seems Bulla was somewhat of a catchall that first caught because Linnaeus' Systema was a first pass, and anything roughly similar to that was going to end up in that genus. It's like creating a file hierarchy when you don't exactly know what the project will entail - you'll have to do some reorganization at some point.

Anyway, at first I didn't think much of the incorrect genus, it happens pretty often that species get reclassified when new info becomes available, and let's be real here, Linnaeus put slugs and worms together in a group called Reptilia, so.... But then I looked it up and the genus Bulla and found that it is in an entirely different group of gastropods, the Cephalaspideans, or bubble shells. As I will state for the 80th time in the Annals of Emily's Entirely Obvious Avowals, I am not a taxonomist, certainly not one of Linneausesses' caliber. I don't even consider myself a malacologist. But I was surprised about how far off this one was until I remembered I have a few hundred years of taxonomy at my fingertips that Linneaus didn't. In fact the major division among snails didn't even come about until the 1920s, and that has been superseded for paraphyly. Aaaaanyway... it was also likely that all Linneaus had to go on when classifying this organism was a shell, rather the whole animal. In any case, thanks to the Biodiversity Heritage Library (seriously, it is not hyperbole to say that they are internet heroes, you guys) I can read ALL of the Systema with the fascinated smugness I have earned just be being born in the 21st century. It's perhaps more correct to say that I can LOOK AT all of the Systema, which is, of course, in Latin, and therefore mostly outside my pay grade. Here is the section introducing Bulla:
The naming of Volva volva, or Bulla volva! From the 10th ed. of Linnaeus' Systema.
So, the Animal part of Bulla is like a slug (Limax, at least I think) and the single (univalves) shell (Testa) is "wrapped" (all convoluta) as opposed to spiralis (which I think you can manage on your own). The opening is oblong, longitudinally oriented, and some other stuff I can't get at with Google Translate. You can see how Volva volva would fit in this rather broad description along with many, many, many, many snails.

The species itself is described on the last two lines of the page: it has a shell with two elongated rostra, which are the pointy bits at either end, and sharp grooves (sure, that sounds fine, if vague). He declared the origin to be Jamaica, which subsequent authorities have deemed to in error, and superseded(10)

There you go, the etymological origin of Volva volva. Do you think Linneaus was tittering? I imagine him as so focused and serious, he would have missed the point.

For a word nerd such as myself, or at least one who casually declares herself so in passing, but who admittedly has very little actual knowledge in linguistics, which must be the worst kind, this was a really fun exercise in history of scientific nomenclature and knowledge. I thank Emily Graslie for the inspiration to dive into this question, and my inner 9th grader for tittering in the back of my head this whole time.

References and Miscellany:

  1. I think I just made the adolescents titter even more! SO much tittering!
  2. That's all I can come up with at the moment, seems to reflect some sort of cognitive bias I probably have, but I can't remember the name of that type of bias which I figure means it's unimportant...
  3. Which is also pretty fun to say
  4. I think mine was King Phillip Came Over For Good Spaghetti, which dates me as a pre-Domain girl. But thankfully they've updated the options since then, because, duh, ALL spaghetti is good! So that makes no sense!
  5. Vermes, to Linnaeus must have meant: confusing squshy thing. However, Google translate assures me that the description of the group means "body muscles on one side attached to the base of a rock". By the 10th edition, 23 years later, the system was a lot closer to recognizable organization.
  6. Emphasis mine for fanciness
  7. Some of you reading this, and having any acquaintance with my writing style will probably roll your eyes and say that you WISH I actually had been trained to ignore parentheses...
  8. Which I think my committee would agree is a huge waste of time - KIDDING!
  9. And believe you me, it's pretty lurid reading that includes sections like: "Currently most (but not all [ed. "great."]) taxonomists accept this view and restrict authorship for a taxonomic name to the person who was responsible for having written the textual scientific content of the original description, or in other words, the visibly responsible person for having written down what the publisher finally published."
  10. I'm sure that conversation went like:
"Yeah, that can't be right."
"Let's just assume he was wrong because it was 150 years ago"
"Yeah, you know nothing, Carl Linnaeus!"