Dr. Rob Dillon, Coordinator





Wednesday, September 6, 2017

Not Finding Fontigens cryptica


In July we met Mrs. Lori Schroeder, the remarkable amateur malacologist dedicated to surveying the gastropod fauna of the Bernheim Arboretum and Research Forest south of Louisville, Kentucky.  And In August we convinced ourselves that the tiny hydrobiid shells Lori discovered in debris washed along the banks of Harrison Creek were best identified as those of Fontigens cryptica, The Most Cryptic Freshwater Gastropod in The World [1].

But as of the spring of 2017, neither Lori, nor her colleagues, nor indeed a team of professional karst, cave, and groundwater biologists had found a single living Fontigens anywhere on the Bernheim property.  It was the expert opinion of Dr. Jerry Lewis that populations of Fontigens cryptica are obligately restricted to interstitial spaces in waters flowing through subterranean beds of sand and gravel, equally unlikely to be recovered from creek waters at the surface and from cave waters below.

Removing the mesh trap from a drainage pipe.

One of the many charming gags in the 1987 Hollywood movie, “The Princess Bride” is a scene where our hero and the bad guy wage a battle of wits involving a poison called iocane [2].  Iocane is odorless, colorless, and tasteless.  So the contest begins when our hero brandishes a vial of poison in front of the bad guy, challenges him to put the vial to his nose, and says, “What you’re not smelling is iocane.”

By some similar logic, I myself felt called to not see what everybody else was not seeing in the caves, springs and streams of central Kentucky.  And I also wanted to survey the complete freshwater gastropod fauna of Bernheim, not just its rarest element.  And I also very much wanted to meet my remarkable colleague, Lori Schroeder.

Note the meticulous labels
And on Saturday, 17June17, I was not disappointed at any of the three elements of my quest.  Lori and her husband Jeff met me in the Bernheim parking lot with smiles and greetings and a fresh pink & green gift bag.  And in the bag were four matching Tupperware containers.  And in one of those containers [3] were four zip lock bags.  And in each of those bags was a vial, and in each vial a meticulously-documented and beautifully formatted label and a clear pill capsule, and in each pill capsule a sample of tiny snails.

We started at Lake Nevin, right by the entrance gate.  No, of course we weren’t expecting to discover any Fontigens in a small lake impounded for landscaping purposes.  Poking around in the margins of Lake Nevin I was trying to do something else it probably isn’t possible to do – overtly correct for a known bias.

Normal sampling processes, such as the ordinary methods ecologists use to sample biological communities, are biased against rare species.  Any element with a relative abundance of less than one will be recorded as a zero.  The FWGNA databases show the opposite trend, however.  Number theoretical analysis has suggested that our lists of North American freshwater gastropods are biased for rare species, not against [4].

Longtime readers of this blog are aware that I occasionally preach little sermons [5] about a phenomenon I call “conservation-biased oversampling.”  This is the tendency, quite unapologetic in many published surveys and vivid in the systematic collections held by major museums, for researchers to focus their sampling efforts on species that they think are rare or endangered.  Such efforts, driven by the availability of research funding and the quest for more, are ultimately counter-productive.

So as of 17June17 I was carrying on the hard drive of my computer data documenting three locations where Lori had recovered shells of Fontigens cryptica in the Bernheim Arboretum and Research Forest.  And not one single datum regarding any population of any trash pulmonates that might be inhabiting the property whatsoever.  Which I felt powerfully called to fix.

And such a fine field companion was Lori Schroeder!  So enthusiastic, so interested, so eager to learn.  I got a fist-bump for a limpet.  At one point about mid-morning I was poking around in the backwater of some little stream, pulled up a dead leaf, and found a single Ferrissia fragilis adhering to the underside.  Lori was so excited that she jumped up, gave a little whoop and offered me a fist-bump.  For a plain brown limpet, probably not 4 mm in maximum extent.  A human behavior unprecedented in my long experience.

What a beautiful day, what a lovely part of the world, and what excellent company!  Lori and Jeff guided me to every spring, stream, lake and pond on the Bernheim property, plus a wide assortment of bone-dry creek beds, obscure holes in the ground, and forsaken dunes of dusty organic debris.  We rode up and down the rich old fields of the Harrison Creek valley in the back of Jeff’s pickup truck, checking that series of mesh traps Lori and Jeff had wired onto the drainage pipes in March.

The picnic spread that Lori and Jeff set was spectacular.  In my ordinary life, the only time I ever eat roast beef and ham together is Christmas, maybe.  Lori offered 5 – 6 types of meats and cheeses and 10 – 12 Tupperware boxes filled with an assortment of ice-cold fruits and veggies.  And I’ve got to say, that cold bottle of Kentucky’s indigenous “Ale 8” ginger ale was among the finest things I can ever remember wrapping my lips around.
The cool, clear waters of Harrison Creek sparkled like jewels on that sun-dappled afternoon, a nice population of Pleurocera semicarinata grazing lazily across the horizontally-bedded shelves of limestone.  There wasn’t much debris of any sort in the stream, nor indeed even loose rock, cobble, or cover of any description.  At one point I stopped and looked around myself and counted, from a single vantage point, 82 crayfish.  And I paused to reflect on the selective forces that might drive a freshwater gastropod population into subterranean life – to quit competition for the rich periphyton resources potentially available in such a stream and adapt to the meager rations of the lightless hyporheic zone.

No, we did not find any Fontigens cryptica on that long, fine day at Bernheim [6].  Last I heard, Lori and Jeff were talking about assembling a Bou-Rouche sampling device from the materials available at the local Tractor Supply Company, basically a piston pump driven into the creek bed, to continue the quest.

But in my personal opinion, the world already has enough populations of pale, white, 2 mm snails crawling through interstitial spaces deep in our subterranean gravel deposits.  What this world needs is more Lori Schroeders. 

Notes

[1] My previous posts in this series:
  • Lori Schroeder’s Tiny Snails [17July17]
  • The Most Cryptic Gastropod in The World [6Aug17]
[2] The battle of wits from The Princess Bride [YouTube]

[3] If you’re curious, the other Tupperware containers held a big honkin’ Campeloma from nearby Beech Fork River, a sample of Pleurocera and Physa from nearby Sunfish Creek, and a sample of Pleurocera and Campeloma from The Land Between The Lakes.

[4]  See the analysis of species richness in my overall Synthesis of the FWGNA Atlantic drainage data here: [FWGNA Synthesis]

[5] I coined the term “conservation-biased oversampling” in my post of 19Mar12, and touched on it again 6Jan14 and 16Oct15.  See:
  • Toward the Scientific Ranking of Conservation Status – Part III [19Mar12]
  • Why Is Rarity? [6Jan14]
  • To Only Know Invasives [16Oct15]
[6] Our complete list of 17June17:  Found everywhere = Physa acuta, Menetus dilatatus, and Lymnaea humilis.  Found in the lakes and ponds = Lymnaea columella, Gyraulus parvus, and Helisoma trivolvis.  Found in the creeks = Pleurocera semicarinata semicarinata, Physa gyrina, Ferrissia rivularis, and Ferrissia fragilis (outside the gate).