Nevada Desert Worldview Collision

Editor’s Note – Last month we explored the relationship between the worldviews of Art, Science, and Public Policy.  This month we push onward into the worldviews of Business and Commerce, about which I know even less, as we shall see.

Sometimes, I identify snails for money.  I hasten to add that I am always happy to do so for free, if your specimens (or jpeg images thereof) are accompanied by good data, especially if the request is courteous. But sometimes I receive requests from environmental consultancies, who have themselves been contracted to collect the specimens in question, and they expect to pay me as a subcontractor.  Fine, I’ll take your money.  I charge $25 per sample.

Pyrgulopsis kolobensis, Nevada

So in the spring of 2020 I received my first inquiry from an officer of an environmental consulting operation in Colorado whom I will identify as Ms. Nickle-Chaser, or N-C for short.  She wrote a single line over a forward from a mutual colleague recommending me to identify “springsnails in Northern Nevada,” simply adding, “Would you be able to help?” 

I replied in the affirmative.  And there followed the usual back-and-forth about contracts, work authorizations, chains-of-custody and so forth.  I am an utter foreigner in the world of business and commerce – I understand that the motivation is money but cannot imagine how anybody could be so motivated.  I am able to cooperate in such situations as a dog commanded to sit and shake.

Nor, in retrospect, did Ms. N-C understand the language of science and technology in which I addressed her.  Here is a quote from quite early in our negotiations, 29Apr20: 

"I usually work with samples preserved in 70% ethanol, although higher concentrations are better.  The USPO pitches a fit about shipments containing ethanol, however, as do some of the private carriers, sometimes.  So a trick is to put the snails in a little unbreakable vial full of ethanol, and then stuff cotton down in the vial, and then pour off any excess ethanol.  So you can reassure the clerk that your shipment does not contain any liquids.  Just wet cotton, right?"

So, a few weeks later I got an email heads-up from N-C that a 15” x 12” x 15” box weighing 19 pounds was on its way from Denver to Charleston, by UPS next-day air.  And she noted, “Ice will be partially melted I expect.”  Nineteen pounds flown across the country by overnight express?  Good grief, I thought to myself – how much must that cost?  Surely whatever I charge for the identification of a few samples of snails will be dwarfed by the cost of their shipping, yes?

 

And indeed, six samples did arrive quite promptly the following evening.  Each was contained in a wide mouth 500 ml Nalgene bottle of (what smelled like) denatured ethanol, packed in ice, packed in a cooler, double-bagged, packed in a box, elaborately taped, dripping a puddle on my front porch.

 

I was disappointed not to find any locality data for the six samples – just number codes written on the bottles.  Looking back at our early correspondence, I probably should have emphasized the importance of such data with greater urgency.  I do save data on the distribution of all freshwater gastropods collected across the entirety of North America into the FWGNA database.  My excel spreadsheet has 13 columns, including not just state, county, latitude and longitude, but also collector and date of collection, and those data are just as important as the sample specimens themselves, and indeed the latter worthless without the former.

Central Eureka County, Nevada

So I requested locality data in my email confirming receipt, and Ms. N-C replied with lat/long coordinates the next day – six tiny green cracks in the arid Cortez Mountains of Eureka County, Nevada.  And I went to work.

 

The samples turned out to be quite various.  One contained a beetle and a pebble.  Two were unpicked bulk samples, one of which ultimately proved to include snails, and the other of which did not.  And three were clean samples of snails.  These were my results for the four samples that contained snails, as I ultimately reported them on 8June20:

• Three of your samples contained Pyrgulopsis kolobensis, one of the more widespread springsnails of the Great Basin, ranging eastward into Utah.
• One of your samples contained Pyrgulopsis gibba [1], also widespread, ranging west into California.
• Two of your samples also contained common pulmonate gastropods, Lymnaea cubensis and Physa acuta.

And I concluded, “Attached you will find an excel spreadsheet with my detailed results, and an invoice, in the amount of $125.” [2]

 

This information apparently satisfied my customer, and my customer’s client as well.  For in the spring of 2021 I received a second inquiry from N-C, which I was again happy to answer in the affirmative.  And negotiations were exchanged, very nearly identical to those we had exchanged in 2020.  N-C had originally expected to send me “several samples in the June or July timeframe,” but her field trip was slightly delayed.  Here is the message I received 24July21: 

"Hi there. I just wanted to let you know that we are going to begin spring sampling for snails starting tomorrow and will be shipping them toward you hopefully on the 29th but may ship it out on the 30th. We will try to overnight that and get it to you rapidly.  Thanks."

The next morning I sent Ms. N-C a reassuring reply, to the effect that I am retired, and in no hurry whatsoever.  And in boldface I asked her this question: “Why are you planning to send your samples to Charleston by overnight express?  Why not good, old-fashioned US Snail-mail?”  And I signed it, “What is your hurry? Rob”

 

At 10:30 Friday morning 30July21, a three-foot cooler appeared on my doorstep, containing 10 double-bagged 500 ml Nalgene bottles of what smelled like denatured ethanol packed in ice.  Good God, that thing must have weighed 40 pounds.  I acknowledged receipt immediately, reminding her about the necessity of locality data, for which (one would think) there might have been room in each of the 500 ml bottles, somewhere.  And in her reply of 11:46 AM, N-C answered the question I had asked her five days earlier as follows: 

“Years doing water quality monitoring taught me the best way to send samples.  Those suckers are worth thousands of dollars, when you factor in time spent planning, surveying, shipping, etc.  It would be a bummer to have to go back out and resample on our dime.”

And she did follow up with the locality data.  And at that point, there was no reason to argue with her about the 40-pound overnight shipment.  I suppose I might have reviewed some of the differences between a sample of water and a sample of preserved freshwater gastropods, and explored the consequences those differences might suggest in shipping methodology.  But her frame of reference was monetary, not scientific.  She was speaking a language that I did not understand, and I understood that.

 

So again, I went to work.  All ten of the 2021 samples also turned out to have been collected from Eureka County, Nevada, but from wetter environments than the 2020 samples.  Most of these were from ponded springs in pastureland, impacted by cattle.  Only two samples contained hydrobiids (P. kolobensis) but all ten contained pulmonates, with six species represented [3], most interestingly Lymnaea (Galba) bulimoides [4].  I sent Ms. N-C a spreadsheet, a formal report, and an invoice for $250 on 5Aug21, and received payment on 17Sept21.

Lymnaea (Galba) bulimoides, Nevada

And my satisfied customer contacted me again in the springs of 2022 and 2023, and very similar business transactions occurred.  Big coolers appeared on my doorstep by overnight express, filled with ice and Nalgene bottles but not locality data.  The 2022 shipment, ten samples collected from the vicinity of the town of Beatty in Nye County, Nevada, were almost entirely of Physa acuta, with a sprinkling of L. humilis.  For some reason it especially irritated me to see hundreds of dollars spent shipping trash snails across the country by overnight express.  But on the other hand, I was beginning to accumulate a nice collection of free coolers.

 

At this point I feel called to set aside the orderly unfolding of my narrative, and confess a personal shortcoming.  Not only are the language, values, and culture of the World of Business foreign to me, I am unsympathetic to them.  I have spent my entire career with my right foot firmly planted in the World of Science, and my left toe delicately touching the World of Public Policy [5].  In both of those worlds, Pyrgulopsis and Physa are entirely different things.

 

As a scientist, I know that Bob Hershler kicked the five (mostly eastern) species of Pyrgulopsis listed in the (1980) Burch cannon [6] up to 54 (western) species in 1994 [7], and that by the end of his career, Bob was recognizing 126, mostly on the basis of negligible DNA sequence divergence and penial characters of dubious biological significance [8].  My left toe tells me, however, that the Nevada Division of Natural Heritage lists 76 nominal species of Pyrgulopsis within its vastly trapezoidal borders, the great majority of which are ranked “G1 = critically imperiled globally.”

 

So, if Ms. N-C were to discover a population of 3 mm prosobranch snails in a Nevada spring, I might be able to understand some special care in their shipment to an expert across the country.  But if she were to find a population of “those suckers” bearing thin, sinistral shells in the ditch behind a McDonald’s restaurant licking the special sauce off the back of a Big Mac wrapper, she could just send me a jpeg, am I right?  But please, in any and all cases, regardless of what those suckers look like, is it too much to ask for locality data?

Charleston.  August 31, 2024

We were headed for a worldview collision.  On 17July24 I received what had (by that point) become my annual greeting from Ms. N-C, reporting that she had a “very small project in Nevada that needs a snail ID on perhaps 3 samples,” and asking if I would be able to assist.  And I replied that I would be happy to help as usual.

 

And on 31Aug24 a hefty 1.5’ x 2’ x 2’ box arrived with a thump on my doorstep, overnight air from Nevada.  It weighed in excess of 13 pounds.  Inside the box (1) I found four layers of plastic bags (2): damp, wet, soaked, and dripping puddles on my wife’s dining room table.  And inside the fourth bag was (3) a little red cooler exorbitantly taped with three layers of a deceptively-strong clear packing tape that defeated every knife in my kitchen.  And sloshing about within that cooler was (4) a single 500 ml Nalgene bottle of alcohol.  And inside that bottle of alcohol, I found (5) one, single little shell.

 

Not a snail, mind you, a shell.  A single lymnaeid shell of 5.5 mm standard length, translucent in its pristine emptiness.  It had belonged to an individual Lymnaea (Galba) cubensis/viator, which if not a trash snail exactly, let me simply say that whole government agencies have been charged to eradicate.  Thirteen pounds of packing material for an empty shell that could not weigh more than 80 mg.

Lymnaea (Galba) cubensis/viator

 

And where is my GDMF locality data?!?? Vainly I pawed through 13 pounds of dripping debris on my wife’s dining room table for any collection information – where was this specimen collected, when and by whom?  All I found was elaborate chain-of-custody paperwork marked simply “Nevada.”

 

I suppose, in retrospect, I should have laughed.  But in fact, I lost my temper entirely.  I was overwhelmed by the absurdity of the situation in the World which I call home.  Having never had a phone number for N-C, I went to my desktop computer to fire off an email, acknowledging receipt.  And I characterized her packing job as “stupid, just plain stupid,” which (I now realize) was over the top.  I continued that I had “no idea whose money she was wasting,” but that I would “no longer be a part of it.”  And I concluded [9], “Here’s the identification of your crappy little shell (Lymnaea cubensis/viator).  But you can keep your crappy $25!”

 

Looking back on that email, with over a year to cool down now, I owe an apology to Ms. Nickle-Chaser.  She was just trying to run a business, and her subcontractor went nuts on her.  The contracts I signed simply said “snails,” and in the world of business, a snail is a snail, even if it’s just a shell.  I feel sure that N-C had adequately budgeted for the elaborate shipping of that empty shell in whatever contract she had signed with whatever strip mall developer or strip mine digger had engaged her services, and that a couple hundred bucks meant nothing to her, much less to them.  I was butting in on a business decision made by Ms. N-C, just as I butt in on that artistic decision made by Ms. Julia Galloway last month.

The world of business and commerce is not compatible with the world of science or the worldview of public policy.  There is no relationship between playing baseball, playing banjo, and playing Hamlet.  But those worldviews are not incompatible either.  Just very simply, and very profoundly different. 

 

I speak the language of science fluently; I can speak a dialect of pidgin-policy; I am profoundly deaf to business. And so, I apologize to Ms. Nickle-Chaser.  But I cannot promise her it won’t happen again, if she ever attempts to reconnect with me, which she has not.

 

Notes

 

[1] For figures of the shell and penial morphology of Pyrgulopsis gibba, together with a brief review of the systematics and evolution of western Pyrgulopsis in general, see:

• Just 125 species of Pyrgulopsis in the American West [7Sept22]

[2] I did not bill for the clean beetle/pebble sample.  But did bill $25 for the snailless bulk sample I had to pick.

 

[3] Lymnaea humilis (8 sites), L. bulimoides (4), Physa acuta (4), L elodes (2), L stagnalis (1), Aplexa elongata (1).

 

[4] In 2021 I was still identifying bulimoides (erroneously) as a subspecies (“techella”) of Lymnaea (Galba) cubensis.  For a review of my laborious untangling of the confusion between bulimoides and cubensis/viator, see:

• What is Lymnaea bulimoides? [13Feb24]
• Oregon, bulimoides, or bust [13Feb25]
• The phantom lymnaeid of the Pacific Northwest [11Mar25]
• Lymnaea (Galba) bulimoides and the NCBI GenDump, with lecture notes on the scientific method [8Apr25]

[5] Well actually, I spent most of my career a sojourner through a third world entirely, that of Education.  And left little mark in that strange land

[6] This is a difficult work to cite.  J. B. Burch's North American Freshwater Snails was published in three different ways.  It was initially commissioned as an identification manual by the US EPA and published by that agency in 1982.  It was also serially published in the journal Walkerana (1980, 1982, 1988) and finally as a stand-alone volume in 1989 (Malacological Publications, Hamburg, MI).

[7] Hershler, R. (1994) A review of the North American freshwater snail genus Pyrgulopsis (Hydrobiidae).  Smithsonian Contributions to Zoology 554: 1 - 115.

 

[8] For more about the career of Dr. Robert Hershler, and his model of the evolutionary relationships among populations of the hydrobiid genus Pyrgulopsis, see:

• My Buddy, Bob [6July22]
• Just 125 species of Pyrgulopsis in the American West [7Sept22]

[9] But added as a PS, “Thanks for the cooler.”

Fun with Campeloma!

Editor’s Notes: The essay that follows is the third in a three-part series on the systematics and taxonomy of viviparid gastropods.  I’d recommend that you back up and read my essays of [9Mar21] and [5Apr21] before going forward, if you haven’t already.

It was subsequently published as: Dillon, R.T., Jr. (2023c)  Fun with Campeloma!  Pp 97 – 110 in The Freshwater Gastropods of North America Volume 7, Collected in Turn One, and Other Essays.  FWGNA Project, Charleston, SC.

Hey boys and girls!  Want to match wits with an international team of 16 professional scientists?  Click the picture below and download our keen quiz #1!

The figure shows representative shells from the six species of North American Campeloma sequenced by Dr. Björn Stelbrink and his colleagues for their worldwide viviparid gene tree [1].  If you click it, you can download a pdf circular that also reprints the Burch/Vail dichotomous key [2] that Dr. Björn and his team used to identify the snails that bore those six shells.  How many can you get right?  The answers were hidden in our March essay, posted [9Mar21].

Keen Campeloma Quiz #1

So now kids, do you think you’ve got what it takes for an exciting career in the fast-growing field of freshwater gastropod Malacology?  Are you looking for a role model?  Look no further than the example set by our colleague Dr. Steven G. Johnson, currently Dean of the College of Science at the University of New Orleans [3].  The 13 papers he published on the evolutionary biology of Campeloma 1992 – 2007 are as good as any body of work on any malacological topic anywhere, ever.  I’ve listed my favorites at footnote [4] below.

Over that 16-year period, Dr. Steve brought a variety of techniques – allozyme electrophoresis, flow cytometry, mtDNA sequencing – to bear on the evolutionary relationships among dozens of populations of Campeloma, initially sampled throughout the eastern US, then subsequently focused on a sweeping arc of Atlantic and Gulf drainages from South Carolina to Louisiana.  He documented, quite thoroughly and beautifully, multiple origins of parthenogenesis in these populations – sometimes spontaneously by autodiploidy and sometimes by allotriploidy, through hybridization and backcrossing.

The grayscale background of the figure below shows the study area for a 1999 paper that Dr. Steve published with Eric Bragg [4].  He assigned these particular 31 Campeloma populations [5] to five specific nomina using the same Burch/Vail dichotomous key that you used for Keen Quiz #1, with an eye toward type localities.  So populations inhabiting the Wekiva River drainage must be C. floridense by definition, and populations inhabiting the Ochlockonee must be C. parthenum.  Campeloma limum was described from South Carolina, so that name would be appropriate for Atlantic drainages, and C. geniculum was described from the Flint River, so appropriate for Gulf drainages [6].  The assignment of Say’s specific nomen Campeloma decisum to populations west of the Mobile Basin was a vanilla call, by shell only.

It is interesting to notice that at no point in no body of water ever sampled by Dr. Steve Johnson during his entire 16 year career did more than a single nominal species of Campeloma occur sympatrically.  Where (sexual) C. limum populations and (sexual) C. geniculum populations have apparently come into contact, he found parthenogenic populations which he identified by a third name, C. parthenum.

Johnson & Bragg Fig 1, Stelbrink mapped in red

So, Johnson & Bragg sequenced the mitochondrial cytB gene for 1 – 5 snails sampled from each of these 31 populations.  Their mtDNA gene tree (maximum parsimony) showed six distinct C. parthenum sequences (and one for C. floridense) scattered haphazardly inside a large C. limum cluster, with C. geniculum on one outside branch and C. decisum on another.  Nominal decisum and nominal geniculum are apparently separated by a big, beautiful discontinuity of some sort at the Mobile Basin, but Dr. Steve’s data did not address whether that barrier is reproductive or merely geographical.

Which brings us back to Dr. Björn Stelbrink’s study of worldwide viviparid phylogeny with which we kicked off this essay [1].  Because Dr. Björn’s little sample of six nominal Campeloma species, marked in red on the map above, was centered on the Mobile Basin and North Alabama, right where Dr. Steve Johnson mapped his mysterious discontinuity.  And although Dr. Björn’s group only analyzed single snails from single populations for each of those six species in the old-school U1S2NMT3 gene tree we reviewed in March, reference back to his team’s supplementary table S1 reveals that sometimes they actually sequenced two.

So the map above shows samples from two populations of C. decisum, two populations of C. decampi, and two populations of C. regulare, as well as singletons for parthenum, geniculum and limum.  All nine of these individual snails were identified using the same Burch/Vail key everybody has used for 40 years and sequenced for three genes [7].  And this suggests a test.

If the morphological characters upon which the Burch/Vail key was based fairly reflect the evolutionary history of the Campeloma populations which bear those shells on their backs, one would expect the two snails that Dr. Björn identified as decisum1 and decisum2 to be the most similar to each other genetically, and ditto for the two snails identified as decampi1 and decampi2, and ditto for regulare1 and regulare2.

The figure below is a simple neighbor-joining network generated by the software inside GenBank, connecting the nine CO1 sequences deposited by Dr. Björn Stelbrink for his six nominal species of Campeloma, with the nearest neighbor for each of the six test snails identified by a red arrow.

Of the six nearest-neighbors, only one matched correctly.  The nearest neighbor of decisum1 was in fact decisum2 (98.5% sequence identity).  But oddly, the nearest neighbor of decisum2 was not decisum1, but rather decampi2, with which it demonstrated 99.1% identity.  And further, the nearest neighbor of decampi2 was not decampi1 (by a long shot), but mutually with decisum2.  The nearest neighbor of decampi1 was decisum1, as was the nearest neighbor of regulare1 as was the nearest neighbor of regulare2.  In fact, of the six CO1 sequences obtained for nominal species pairs, only the one sequence, that of decisum1, correctly matched its sister.

Neighbor-joining network from Stelbrink [1] COI sequences

Turning now to the two nuclear genes sequenced by Dr. Björn’s team, very little variance was apparent among the nine sequences for either, none correlating with the taxonomy.  In the histone H3 data set (328 bp), the pair of decisum sequences matched each other and the singleton parthenum sequence.  That group of three differed by a single A/G transition at position 262 from a group that contained both decampi sequences and both regulare sequences.  The limum sequence and the geniculum sequence were both a bit more distinctive, differing from each other (and from the decisum group) by four transitions.

For 28S data set (1,058 bp) the two decisum sequences were again identical to each other, to the parthenum, and to one of the regulare.  The other regulare differed by a single A/G transition at residue 535 and the geniculum differed by a single C/T transition at residue 833.  The two decampi were also again identical to each other and (this time) to the single C. limum sequence.  That set of three differed from the decisum cluster by a two-nucleotide indel at positions 835-6, which is surprising, especially given the geography, and I think significant.  There most certainly is some genetic structure to this set of 3x9 DNA sequences, but the 19^th-century taxonomy is not capturing it.

Hey kids, are you ready for some more fun?  Now’s the time to try Keen Quiz #2, shown on page 3 of that same pdf circular you downloaded at the beginning of this essay.

Can you find the three secret-decoder Campeloma hidden in the weeds?  Now can you identify those three shells using the Burch/Vail key?  Circle each shell and write what you think it is in the spaces provided.  Answers below, no peeking!

Not uncommonly, when I am casting about for larger analogies to apply to the messy evolutionary biology of freshwater gastropods, I find myself looking toward the botanical, rather than to the zoological [8].  And in the case of North American Campeloma, I have found inspiration in the dandelions.

Keen Campeloma Quiz #2

The reproductive biology of dandelions is as diverse as one could possibly imagine – outcrossing, selfing, parthenogenetic cloning, sexual/asexual cycling, everything.  An elaborate taxonomy built up in nineteenth-century Europe to describe all the morphs, forms, subspecies and sections of dandelions, but today, most botanists refer the entire yellow-blooming, blowball-sprouting mess to Taraxacum officinale, because after a couple hundred years of squinting at them and screwing around with them, all dandelions pretty much look alike.

The widespread incidence of parthenogenesis in North American populations of the viviparid genus Campeloma voids the biological species concept and necessitates a retreat to the morphological.  And since (judging from the work of Johnson and Stelbrink) there are apparently no consistent phenotypic characters, shell morphological or otherwise, by which Campeloma populations can be distinguished, the FWGNA Project will refer all populations of Campeloma to the oldest available specific nomen, Campeloma decisum (Say 1817).

But how about inconsistent characters?  Nothing in the paragraph above should be interpreted as foreclosing the recognition of C. decisum subspecies – geographically separate and morphologically different forms – even if they intergrade, even if there is no genetic basis for the distinction [9].  The shell morphology of Campeloma populations most certainly does vary regionally.  Indeed, big rivers of the American interior are often inhabited by populations of Campeloma bearing distinctly heavy shells, which have traditionally been identified as C. crassulum Rafinesque 1819, almost certainly a case of cryptic phenotypic plasticity [10].  The FWGNA Project recognizes these populations at the subspecific level, as C. decisum crassulum, just as we recognize heavily-shelled Pleurocera canaliculata canaliculata in those same big rivers, and more gracile P. canaliculata acuta in the little streams that feed into them.

And certainly Call’s (1886) floridense could be saved as a subspecies name for C. decisum with brown apertures, right?  And Binney’s (1865) decampi also seems a likely candidate for retention at the subspecies level.  Although I have no personal observations to contribute, the figures and photos I have seen (e.g., shell #1 way up above) seem to suggest that Campeloma populations in North Alabama may indeed bear shells that are atypically slender and higher-spired, likely for ecophenotypic reasons we do not understand.  And the nomen “decampi” has appeared in recent literature connected to some conservation concerns [12].

As we have often pointed out when faced with analogous situations in the North American pleurocerids, the Latin nomina assigned to biological populations may bear an important indexing function, as well as evolutionary significance.  So, in addition to crassulum and floridense and (perhaps) decampi, it would be a shame to see the names that Dr. Steve Johnson used for his important works – geniculum (Conrad 1834), limum (Anthony 1860), and parthenum Vail 1979 – forgotten by the google machine.  Those names have been useful to index Campeloma populations across the southeastern United States for quite a few years now.

But here’s a big problem, kids.  And maybe you can help!  Let’s look at how you did on Quiz #2.  Those secret-decoder shells didn’t have brown apertures, did they, so they are not floridense.  Did you think that their whorls have angled shoulders, or are their shoulders rounded, or do they have no shoulders at all?  Angled?  So are those shells broadly ovate or narrowly ovate?  Are they Campeloma limum?  Campeloma geniculum?  Did any of you guess Campeloma decisum for any of the secret-decoders?

Surprise!  All three of the shells hidden in the dandelion patch above are topotypic Campeloma decisum, collected from a pond in Philadelphia’s Fairmount Park, along the banks of the Schuylkill River, where Thomas Say almost certainly explored in 1817.  The snails that bore those three shells were C. decisum, by definition.

That makes them what scientists call a “control,” and what kids like us call super-duper secret-decoders.  Every other Campeloma population, bearing every other shell shape, form, or size, that anybody has ever seen, are (scientifically-speaking) unknown.  That includes all nine of those populations identified by Dr. Björn Stelbrink’s team we had fun with in Keen Quiz #1, and all 31 of those populations studied by Dr. Steve Johnson.  If Dr. Björn’s shells and Dr. Steve’s shells look like the secret-decoders, their correct identification is C. decisum, by definition.  Only if they look different, can they be identified as anything else.

Did Jack Burch and Virginia Vail look at secret-decoders first, when they were making their 1982 dichotomous key?  I don’t know.  The University of Michigan Museum of Zoology does (indeed) hold a couple lots of Campeloma decisum collected from the Schuylkill River in Philadelphia, so it is possible.  But I don’t know about you, kids, I cannot make the Burch/Vail key work at all.  I get messed up early, way up at couplet 14, because I really think that at least some of our secret-decoder shells demonstrate “angled” shoulders, which sends me down the wrong path.

So it would be great to save Dr. Steve Johnson’s limum, geniculum, and parthenum as subspecies names, it really would.  But even setting aside the Burch/Vail key, I cannot distinguish limum collected from its type locality (“South Carolina”) and control decisum from Philadelphia.  Could I distinguish geniculum or parthenum from decisum/limum?  I don’t know that, either [13].  I don’t have control collections from the Flint River or Lake Talquin, or really anywhere in the Gulf drainages of Georgia and Florida.

Boys and girls, I’m going to leave this challenge to you all, the next generation of malacologists. Here’s what I want you to do.  Mail your completed quiz sheets to “Fun With Campeloma,” P.O. Box 31532, Charleston, SC 29417.  Don’t forget to include your name and address and $1.25 for postage and handling.  No, I won’t grade them – I don’t know the right answers myself.  But all entries will be entered into a random drawing.  And one lucky winner will get a genuine FWGNA deputy’s badge and a license to classify the subspecies of Campeloma decisum throughout North America any way he or she wants.

But one last warning, kids, before we sign off this month.  You may hear some grown-ups asking why we have to fall back to an 18^th century morphological species concept, as I so boldly asserted ten paragraphs above.  Accepting that the biological species concept is void for Campeloma, those grown-ups may be suggesting that we move forward to the phylogenetic species concept, or one of those other recent concepts based on gene trees.  Don’t all the genetic data we have reviewed this month suggest some sort of evolutionary structure to these populations?  Surely all the Campeloma populations spread across half of North America aren’t equally related to each other, are they?  DNA sequences and fancy tree-generating algorithms are a more scientific way to name snail populations than some kid’s subjective judgement calls on fat brown shells, right?

Be careful around grown-ups like that, boys and girls!  They’re not malacologists, they’re phylogenetic systematists!  We’re going to learn a lot more about phylogenetic systematics in the next few months, and why ideas like that don’t hold water.  So stay tuned!

Notes:

[1] Stelbrink, B., R. Richter, F. Köhler, F. Riedel, E. Strong, B. Van Bocxlaer, C. Albrecht, T. Hauffe, T. Page, D. Aldridge, A. Bogan, L-N. Du, M. Manuel-Santos, R. Marwoto, A Shirokaya, and T. Von Rintelen (2020)  Global diversification dynamics since the Jurassic: Low dispersal and habitat-dependent evolution explain hotspots of diversity and shell disparity in river snails (Viviparidae).  Systematic Biology 69: 944 – 961.

[2] This is a difficult work to cite.  J. B. Burch's North American Freshwater Snails was published in three different ways.  It was initially commissioned as an identification manual by the US EPA and published by the agency in 1982.  It was also serially published in the journal Walkerana (1980, 1982, 1988) and finally as stand-alone volume in 1989 (Malacological Publications, Hamburg, MI).

[3] Rule #1 is, stay out of museums! Those musty cabinets of dusty shells will kill your scientific career faster than a confession of the Apostle’s Creed.  And Rule #2 is, never return emails from anybody who ever has.

[4] Johnson, S. G. 1992. Spontaneous and hybrid origins of parthenogenesis in Campeloma decisum (freshwater prosobranch snail). Heredity 68:253-261.  Johnson, S.G., R. Hopkins, and K. Goddard. 1999. Constraints on elevated ploidy in hybrid and non-hybrid parthenogenetic snails. Journal of Heredity 90: 659-662.  Johnson, S.G. and W. Leefe. 1999. Clonal diversity and polyphyletic origins of hybrid and spontaneous parthenogenetic Campeloma (Gastropoda: Viviparidae) from the southeastern United States. Journal of Evolutionary Biology 12:1056-1068.  Johnson, S.G. and E. Bragg. 1999. Age and polyphyletic origins of hybrid and spontaneous parthenogenetic Campeloma (Gastropoda: Viviparidae) from the southeastern United States. Evolution 53:1769-1781.  Johnson, S.G. 2000. Population structure, parasitism and survivorship of sexual and parthenogenetic Campeloma limum (Gastropoda: Viviparidae). Evolution 54:167-175.  Johnson, S. G., 2005. Mode of origin differentially influences the fitness of parthenogenetic freshwater snails. Proc. Roy. Soc. Lond. B. 272: 2149-2153.  Johnson, S. G. 2006. Geographic ranges, population structure and ages of sexual and parthenogenetic snail lineages. Evolution 60:1417-1426.

[5] The 1999 paper by Johnson with W. R. Leefe surveyed 55 populations.  The Johnson & Bragg paper from which the figure was extracted retained the Johnson & Leefe numbering system but focused on a slightly-less-cluttered 31-population subset.

[6] Johnson never sampled the Flint River proper, up in Georgia, where it comes in close contact with the Ocmulgee R., which drains east to the Atlantic.  This would certainly have been intellectually fascinating, and might well have clarified Campeloma taxonomy substantially, and the omission drives me nuts, absolutely nuts.

[7] The Stelbrink team sequenced mitochondrial CO1 and nuclear 28S and H3.  They did not (alas) sequence mitochondrial cytB, so their data cannot be integrated with that of Steve Johnson.

[8] The most obvious example is my “USR” model for life history evolution in the freshwater mollusks, which I patterned after J. P. Grimes” CSR model for the plants: Competitors, Stress-tolerators, and Ruderals.  That idea was the unifying theme of my (2000) book for Cambridge University Press.  I thought it would make me rich and famous.  I wonder why not.

[9] To refresh your memory on the definition of the word, “subspecies,” see:

• What Is a subspecies? [4Feb14]
• What Subspecies Are Not [5Mar14]

[10]  Quoting Dillon and colleagues [11], “phenotypic plasticity may be considered cryptic when intrapopulation morphological variance is so extreme as to prompt an (erroneous) hypothesis of speciation.”  To refresh your memory:

• Pleurocera acuta is Pleurocera canaliculata [3June13]
• Pleurocera canaliculata and the process of scientific discovery [18June13]
• Elimia livescens and Lithasia obovata are Pleurocera semicarinata [11July14]

[11] Dillon, R. T., S. J. Jacquemin & M. Pyron (2013) Cryptic phenotypic plasticity in populations of the freshwater prosobranch snail, Pleurocera canaliculata.  Hydrobiologia 709: 117-127. [PDF]

[12] Haggerty, T.M. and J.T. Garner (2008)  Distribution of the armored snail (Marstonia pachyta) and slender Campeloma (Campeloma decampi) in Limestone, Piney, and Round Island Creeks, Alabama.  Southeastern Naturalist 7: 729-736.  Haggerty, T.M., J.T. Garner and L. Gilbert (2014)  Density, demography, and microhabitat of Campeloma decampi (Gastropoda: Viviparidae). Walkerana 17: 1 – 7.

[13] But reading all the way down through the Burch/Vail key to couplet #19, one gets the strong impression that even Virginia Vail could not distinguish her Campeloma parthenum from Campeloma decisum.  The basis for the decisum/parthenum distinction is geographical only.  If you find it in the Ochlockonee River, it’s parthenum.  Otherwise, it’s decisum.  So parthenum is an allotriploid hybrid of nominal limum and geniculum, which Burch/Vail distinguished from decisum/parthenum by that problematic shoulder-shape couplet #14?   So two nominal species with angled shoulders hybridize to form populations with rounded shoulders?  Hmmm.  That’s as far down this rabbit hole as I care to go, even in a discursive footnote.

The flat-topped Helisoma of The Everglades

Editor’s Note – This essay was subsequently published as: Dillon, R.T., Jr. (2023c)  The flat-topped Helisoma of The Everglades.  Pp 235 – 243 in The Freshwater Gastropods of North America Volume 7, Collected in Turn One, and Other Essays.  FWGNA Project, Charleston, SC.

Spoiler Alert.  This is the beginning of a series on Floridean Helisoma that will span eight additional episodes, continuing on into 2023.  It will materialize that the 40-Mile Bend is not the type locality of Helisoma duryi [3Dec20], nor is "Helisoma duryi" the best identification for the snails I collected there in 2018 [7Feb23].  But the observations I made in The Everglades turned out to be important.  And it's a good story.  Read on.

Albert G. Wetherby (1833 – 1902) was for six years a professor of geology and zoology at The University of Cincinnati.  Then he got burned out and quit [1].  But in 1879 this little-known scientist published a little-known paper in a little-known journal entitled, “Notes on some new or little known North American Limnaeidae [2].”  And it was there that Planorbis (Helisoma) duryi was first described.

Wetherby described the shell as “thick, shining, straw color, of medium size, slightly waved by indistinct transverse ridges… spire very regular, flat or very slightly concave.”  It was not immediately clear what the author meant by “medium size,” as no measurements were offered, and his figure was without scale [3]. Weatherby noted that the shell [in the singular, 3] before him “was given me several years ago, by Mr. Charles Dury [4], who brought it from the Everglades of Florida.  It was also [5] among the shells received from the Miami country.”

Planorbis (Helisoma) duryi [2]

“The Everglades of Florida” is a big place.  The national park of the modern era is a 2,300 square mile wilderness extending over three South Florida counties.  More broadly, the USGS/FWS defines the Everglades Ecoregion as The Kissimmee River, Lake Okeechobee, and drainage fields south, extending over all or part of 18 South Florida counties, for a total of 7,800 square miles [6].  Even a large-sized snail would be difficult to track in such a place.  Let alone medium.

So, reading Weatherby’s description in the calm of my office here one sunny morning in Charleston a couple years ago, I was stricken with the impression that the type locality of Helisoma duryi might could use a bit of narrowing-down.  And I swiveled my chair and pulled my well-thumbed copy [7] of F. C. Baker’s (1945) “The Molluscan Family Planorbidae” off the bookshelf [8].

As my faithful readership will recall,  Baker’s overly-ambitious monograph was published posthumously, Part I (“Classification and General Morphology”) being left incomplete.  But under the Subfamily Helisomatinae (F. C. Baker 1928), genus Helisoma (Swainson 1840), Subgenus Seminolina (Pilsbry 1934) Baker was able to catalog, prior to his departure for the cloud of witnesses malacological, seven valid taxa: scalare (Jay), preglabratum (Marshall), and five subspecies of duryi.  For the geographical distribution of all seven Seminolina taxa together, he wrote, “As far as known, this group is found only in the peninsula of Florida north to Bradford County [9].”  

Everglades [10], Tamiami Trail in red

The five subspecies of duryi included Wetherby’s typical form and four added by Pilsbry [11]: normale, seminole, intercalare, and eudiscus.  Baker did not distinguish the typical form of duryi from Pilsbry’s subspecies normale, and in fact, does not appear to have examined any typical specimens at all.  But the first locality that Baker listed for Helisoma duryi normale was “Tamiami Trail, 40 miles west of Miami.”  OK, I thought to myself, that’s it.  As a typical locality for Helisoma duryi, if not necessarily the type locality of the species, that should be good enough.

The Tamiami (Tampa-to-Miami) Trail has a longer and more interesting history than one might think.  Work on the initial sections of an automobile highway across the Florida peninsula began in 1915, if you can believe it, just 7 years after Henry Ford debuted his Model T.  The most spectacular section, running east-west across The Everglades, was built between 1923 and 1928, construction teams blasting a canal through the marsh bedrock and raising a roadbed with the fill.  A significant engineering discrepancy that developed between the eastbound and westbound teams was corrected with features now known as the 40-Mile Bend and the 50-Mile Bend, initial plans for a 45-Mile Zigzag ultimately falling out of favor.

Today the 40-Mile Bend area is home to the Miccosukee Tribe of Indians, who operate a museum, a restaurant, a gift shop and a general store.  And airboat rides.  Mom, Dad, and The Kids will find ample opportunity along this entire stretch of the Tamiami Trail to tour the Everglades on airboats of all design and description.

 So Sunday afternoon 21Oct18 I gave my wife a peck on the cheek and pointed my trusty [12] Mazda pickup south toward The Everglades.  And Monday afternoon found me turning off the Tamiami Trail into the 40-Mile Bend boat ramp parking lot.  I emerged blinking and stretching.  And has long been my habit, stuck my hands into my pockets and walked over to the water’s edge to conduct a preliminary assessment.

And what I saw was utterly unlike anything I have ever seen at the end of any other boat ramp any other place in my entire life.  The water was crystal clear to the bottom.  How deep is it in there, I wondered, five feet?  More?  It was impossible to judge at such a sparkling clarity.  And hundreds of bass, bream, and carp, all with their fishy little hands stuck in their fishy little pockets, looked back up at me, hungrily.  With a bamboo pole and a dozen crickets, I could have fed myself for a week.

40-Mile boat ramp

My curiosity thus piqued, I launched my kayak and paddled off into an utterly foreign world.  Heaven knows I have boated hundreds of marshes, swamps, and wetlands of all sorts over the entire eastern USA in my long life.  Without exception, all have been soft-bottomed, muddy, and filled with decaying vegetation – in a word, swampy.  But here I found myself floating over a bottom of limestone rock, through a non-swampy wetland.

True, I did launch into that canal alongside the roadway, which must have been excavated for fill rock.  But even as I paddled out into the marsh, I could look down through crystal-clear water and see solid substrate.  In fact, at one place where the bedrock approached the surface, I got out of my kayak and walked.  On rock, in a wetland!  Little bluegills and bream nibbling the hairs on my leg.  Otherworldly.

And a third remarkable aspect of the Everglades environment, beyond the water clarity and the substrate, dawned upon me as I paddled.  I could find no floating aquatic vegetation whatsoever – no water hyacinth or duckweed or Elodea or Hydrilla or anything that looked like Elodea or anything that looked like Hydrilla.  Floating macrophytic vegetation, so common everywhere else in my many years of kayaking experience, is what I have always thought of as typical Helisoma habitat.  But the aquatic jungle through which I was paddling that afternoon was rooted-emergent and rooted-submerged only.

I found my Helisoma hiding deep in the rooted, submerged macrophytes.  Putting to work the net I mount tied to the stern of my kayak [13], I dipped in the crystal clear water at arm’s length, ran through the grass and weed beds, and with a bit of effort, was able to collect a decent sample of Helisoma.  The snails were almost entirely juveniles, invisible to me at the surface and (more evolutionarily important) to the schools of hungry bream, which I feel sure would have immediately picked off any stray pulmonate foolish enough to raise a tentacle.  They were quite pale in their body coloration – light grayish or even whitish [14].  Perhaps they emerge to graze at night, I thought to myself.

Suddenly my reverie was interrupted by a distant, but fast-approaching roar.  And my thoughts were jerked rudely back sixty years from the warm, sunny October day I was then enjoying in my exotic little patch of paradise.  And cast to the family room of my modest home in Waynesboro, Virginia, and to a favorite television show of my youth.  Lincoln Vail of “The Everglades.”  Airboat coming!

My kayak and I were at that juncture floating invisibly in tall, emergent grasses.  And the thunder was immediately upon me, as quick as I could raise an orange paddle.  Lincoln Vail and his family of passengers veered abruptly to my port side and missed me clean (literally clean) by maybe ten feet.  But the prop wash – or whatever you call the spray those gigantic airboat motors kick up behind them, threw a 40-gallon rainstorm over me, horizontally, in the blink of an eye.

Back at the boat ramp, toweling off, I found opportunity to reflect upon the biological observations of the afternoon.  Every Helisoma I had collected during the previous three hours had been netted from macrophytes submerged in water at depths no less than two feet, with no approach to the surface ever in evidence.  Nor would there seem to be any rationale for an individual Helisoma to approach the surface, given the absence of floating macrophytic habitat in the environment I had just been bathed in.  Nor (indeed) would it be safe even to expose oneself to the surface, if one were a snail of that predilection, given the predation risk from the ravenous schools of bream.  This population of Helisoma must be entirely benthic.  I did not gather any experimental confirmation, but I’ll bet dollars to donuts that the mantle cavities of every individual planorbid I collected that afternoon were 100% filled with water.  No air pockets.

Helisoma from the 40-mile Bend

Now a second observation followed from the first.  I had found perhaps 40 – 50 individual Helisoma, only about 10% of which seemed to be adults.  But those adults did not demonstrate the planispiral shell morphology typically associated with Helisoma duryi, as depicted in Wetherby’s original figure way up above.  Rather, they retained the elongated, obviously-sinistral "scalariform" or "physoid" shell morphology that has come to be associated with the other medium-sized planorbid of The Everglades, Helisoma scalare.  Might the relationship between Helisoma duryi and Helisoma scalaris find analogy in the Helisoma population of Charleston’s Wakendaw Lakes [15]?

By 3:30 I had loaded my kayak back into my truck, exited the 40-Mile parking lot, and turned east toward the rush hour traffic of Miami.  And by 4:45 I was walking in the door of the FedEx shipping center at 21^st Street with a box of Helisoma cradled under my arm [16].  The cost of overnight delivery to St. Paul, Minnesota, turned out to be $99.35.  Ouch.

Next month, our story follows that box.

Notes:

[1] Harper, G. H. (1902) Albert G. Wetherby.  Nautilus 16: 10 – 12.

[2] Wetherby, A.G. (1879)  Notes on some new or little known North American Limnaeidae.   The Journal of the Cincinnati Society of Natural History 2: 93 – 100.

[3] It materializes that there were nine shells in Wetherby’s type lot, and that the diameter of the holotype shell was 19.5 mm.  We’ll follow up in a later post.

[4] Charles Dury (1847 – 1931) was a Cincinnati-area naturalist of the Old School, primarily interested in insects.  His obituary was published in the Ohio Journal of Science 31: 512 – 514.

[5] Interestingly, Prof. Wetherby seems to have been drawn into the subject of planorbids, generally, by the chronic, centuries-old confusion over what exactly is (or was) the Planorbis glabratus that Thomas Say had in his hand when he wrote his description in 1818.  Weatherby thought that most of the planorbids in his “large collection of shells from the Miami country of Florida” might be P. glabratus.  Which is why he wrote "also" here in his description.  This subset is NOT Planorbis glabratus.  Although I didn't pursue this topic any further in 2020, I did come back to it on [7Mar23].

[6] Bailey, R. G. (1980)  Description of the Ecoregions of the United States.  USDA Forest Service Misc. Publication No. 1391, 83 pp

[7] My copy is autographed “Charlotte Dawley Sept. 1950.”  It was then stamped “Rowland M. Shelley.”  It then passed to W. F. (Bill) Adams, who gave it to me in 2007, when he retired from the Wilmington office of the Corps of Engineers.  Thank you, Bill, wherever you are.

[8] Baker, F.C. (1945) The Molluscan Family Planorbidae. Urbana: University of Illinois Press. 530 pp.  For more about Baker and his remarkable work, see:

• The Legacy of Frank Collins Baker [20Nov06]
• The Classification of the Planorbidae [11Apr08]

[9] Bradford county is situated further north than the area covered by the map of the Everglades I have reproduced above.  But Baker’s restriction of Seminolina to areas south of Bradford County will become important in essays to follow.

[10] By Kmusser - Own work. City and Federal lands data source: National Atlas. County and urbanized areas data source: U.S. Census Bureau. Hydrology data source: National Hydrography Dataset. WCAs, EAA, and Management District boundary source: South Florida Water Management District. National Marine Sanctuary data source: NOAA, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=9034125

[11] Pilsbry, H. A. (1934)  Review of the Planorbidae of Florida, with notes on other members of the family.  Proceedings of the Academy of Natural Sciences of Philadelphia 86: 29 – 66.

[12] Well, five of those letters are correct, anyway.

[13]  Here’s how to do it:

• Collecting freshwater snails by kayak [13June11]

[14] I think it is probably a general rule, throughout the Animal Kingdom, that melanin production is induced by light.  I think many of those little Everglades Helisoma may have spent their entire lives in darkness – grazing on macrophytic tissues and detritus deep in the weeds, terrified by the bream.

[15]  The present essay fits somewhere in the middle of an extended saga chronicling my own personal struggle for biological understanding of the large Helisoma.  For background on the Wakendaw Lakes population, see:

• Shell morphology, current, and substrate [18Feb05]
• Juvenile Helisoma [9Sept20]

[16] Somewhat amazingly, to me in any case, I was forced to detour by some random drainage pond in Miami to net up water weed to pack my Helisoma in.  I couldn't find any water weed suitable for packing anywhere in The Everglades.

Freshwater Gastropods and Social Media

Editor’s Notes –This is the fifth installment of my series on the general topic of freshwater snails in the aquarium hobby.  Previous posts have been “What’s Out There?” [9Oct17], “Loved to Death?” [6Nov17], “Pet Shop Malacology,” [21Dec17] and “Snails by Mail” [24Jan18].  But don’t worry.  Full appreciation of Essay #5 is not contingent upon familiarity with Essays #1 – 4.

This essay was subsequently published as: Dillon, R.T., Jr. (2023c)  Freshwater Gastropods and Social Media.  Pp 51 – 55 in The Freshwater Gastropods of North America Volume 7, Collected in Turn One, and Other Essays.  FWGNA Project, Charleston, SC.

I am not social, in any medium.  I don’t even text, much less twitter or tweet or insta-chat or whatever it is that the kids are doing these days.  I understand that social media can be effective tools for communicating on a large scale.  I did join Facebook about ten years ago, in order to “like” a political group of which I was serving as an officer [1].  I regretted it at the time, and regret it now.

In any case, about once a week I gather up my courage and log onto Facebook.  And watch in horror as great garbled masses of disconnected conversations and news and opinions and jokes and photos and videos from family and friends and professional colleagues and high school classmates and Sacred Harp Singing Societies are disgorged simultaneously onto my desk in one gigantic, hideous, stupefying dose.

So several months ago, a Facebook friend called my attention to a group called “Snails, Snails, Snails.”  Heart racing with a mixture of curiosity and dread, I clicked over to the homepage for the group, and what to my wondering eyes should appear, but an internet forum for “lovers, keepers, breeders, and sales of freshwater and saltwater snails and slugs,” boasting 5,442 members!

"Gary doesn't smell so good."

It was a closed group.  So I submitted my CV, top five recent publications, and three letters of reference, and was, after some period of deliberation, duly admitted to membership.  And have subsequently been charmed.

What an engaging assortment of odd-lot humanity!  Mostly young, apparently from a wide variety of backgrounds, hailing from all over the world, unified by the love, yes love often and freely confessed, of gastropods.  Most of the members seem to be freshwater aquarium hobbyists.  Posts about marine gastropods are occasional, as are photos of pet land snails, and even peripheral aquarium fauna, like shrimp.  But I would estimate that, of the perhaps 15 – 20 posts per day, at least 80% have to do with somebody’s freshwater aquarium pet.

Fascinated by the social interactions as they unfolded before me, I resolved to log onto Snails, Snails, Snails every day for 30 days, beginning 25Aug17, and monitor all activity.

I recorded 16 different freshwater gastropod categories receiving mention during my month of observation, totaling 375 mentions.  Of that total, 230 mentions (61%) were of Pomacea diffusa/bridgesii, almost universally referred to as “mystery snails,” apparently the most popular gastropod pet in the home aquarium by far.  Indeed, at some point during the month my attention was called to a pair of independently-operating FB groups dedicated exclusively to P. diffusa, “Mystery Snail and Aquatic Lovers” with 3,166 members and “Mystery Snail Addiction” with 1,818 members [2]. 

The discussion seems to focus on husbandry – food, water quality, life history in culture – not too much different from chatter about aquarium fish, I don’t suppose.  One probably reads more of the “How do I tell if Gary is dead” sorts of questions.  One also reads a surprising number of posts sharing “the cute thing I saw Lightning do,” probably very similar to typical social media interactions about cats and dogs.

The next-most-popular category of freshwater snails in social media seems to be the nerites of all species, with 33 mentions on Snails, Snails, Snails for the month.  This is unsurprising, given the results of the survey of big-box pet retailers I reported in December [3].  The remainder of the species with double-digit mentions during my 30 days of monitoring were “Ramshorns” (24), Melanoides tuberculata (19), Physa (17), Assassin snails (14), and “Rabbit Snails” (Tylomelania, all species) with 10 mentions [4].

I tallied eight mentions of “apple snails” during my month of observation, by which I was able to unambiguously confirm that the author was referring to large, invasive Pomacea maculata/insularum/canaliculata types.  I also caught two mentions of the invasive “Columbian Rams Horn” Marisa.

One young lady in Houston shared an article from the Houston Chronicle entitled, “Harvey Floodwaters bring weird pink things to the Houston landscape [5].”  There were 11 comments and replies, most of the “LOL” sort.  But other comments included "I'll take them 😄" and "I wish I could find some of these here," and "So jealous!  I'm in Illinois and haven't been able to get my hands on a pair."

Without a doubt, significant pent-up demand exists within the community of aquarium hobbyists for large, invasive apple snails.  I counted four separate appeals to purchase such animals during my 30 days of observation, generally of the form, “Does anyone have a LARGE (like, baseball sized) apple snail that they would sell? I LOVE snails and I can't find any that large near me.” 

It is impossible to know, of course, to what extent such requests are satisfied through one-on-one “messaging.”  Typical public replies to such solicitations included “You’d have to find locally. So you should post your location. Shipping adults is dangerous.” or “For channeleds you'd have to find a local seller. I believe it's illegal to ship them over state lines.”  Here’s one (especially revealing) reply: “Haha thank you! Yes our aquarium shop gets lucky once in a great moon and they have a personal tank with one literally apple size so I am always checking in.”

I never saw any misgivings expressed by any member of the Snails, Snails, Snails FB Group about the potential for large apple snails to become invasive pests.  Significant qualms were not uncommonly expressed, however, about the potential for large apple snails to destroy valuable aquarium plants.  One member asked, “How do you stop apple snails from eating your expensive plants?”  After several commiserations, condolences, and expressions of despair, the Group Administrator posted this meme, which I do not understand:

Finally.  I leave you on this Valentine’s Day with one woman’s heart-wrenching testimonial to the love she bore for her gastropod friends.  She posted: 

“My son was in a horrific car accident on Tuesday and almost lost his life. He is home now and doing well but, while i was away i had my kids feeding my snails for me. It did not turn out so well. I lost a banjo catfish, a betta, and all but two of my big apple snails. I am praying these two guys will recover but idk.”

Yes, you read that correctly.  Her son was in an automobile accident, and she is praying for her snails.

Notes

[1] The South Carolinians for Science Education. [SCSE]  Like us on Facebook!

[2]  The list goes on and on, actually.  A simple search for “snails” within Facebook will also return groups called “Land Snails” (742 members), “Tree and Land Snails” (925 members), “Snail Enthusiasts: USA” (1,400 members) and even (I wish I was kidding) “Giant African Land Snails” with 5,800 members.

[3] Pet Shop Malacology [21Dec17]

[4] Others mentioned included Bellayma (6), “Pagoda snails” (5), Thiara scabra (3), “Devil’s Spike” (1), Lymnaea peregra (1), Gyraulus parvus (1), and New Zealand Mud Snails (1).

[5] Houston Chronicle (7Sept17).  Harvey Floodwaters bring weird pink things to the Houston landscape. [html]