Oregon, bulimoides, or bust

Editor's Note – Exactly one year ago, on [13Feb24], I posted an essay in the columns of this blog asking the question, “What is Lymnaea bulimoides?”  And I concluded that essay, “Malacologists of America, we must do better.”  Here is my effort.

L. bulimoides Gahr Pond

Thomas Nuttall (1786 – 1859) was a man of distinction [1].  He was among the first naturalists to explore Arkansas, among the first to botanize California, and the author of the first field guide to the North American birds.  The breadth and depth of his experience with the natural history of temperate America was unequalled in his day, arguably since.  And of the 400,000 pioneers who travelled the Oregon Trail west from its opening in the early 1810s through its heyday in the 1840s – 1860s, Thomas Nuttall was one of the very, very few who ever came back east again.

And packed deep in the luggage he carried with him aboard the merchant brig Alert in 1836 [2], bound from Monterey to Boston with a cargo of cowhides, was the world’s first sample of crappy little amphibious lymnaeids that Isaac Lea [3] ultimately described as Lymnaea bulimoides [4].  And as my wife and I boarded Delta Flight 954 for Portland on the morning of July 31, 2024, in that one tiny distinction, I meant to join him.

 

Never has a freshwater gastropod subsequently so important been subsequently so widely misunderstood.  Lymnaea (Galba) bulimoides is the primary intermediate host of Fasciola hepatica – the livestock liver fluke – in the Pacific Northwest.

Fasciola is a digenetic trematode, which means that it has two hosts, a primary host, typically hooved livestock [5], and an intermediate host, typically a lymnaeid snail.  The worm infects the liver of its primary host, laying eggs which are defecated.  Those eggs hatch into swimming miracidium larvae which find a snail, burrow in, and develop into rediae, which in turn shed swimming cercaria larvae. 

 

In all of those details, Fasciola is no different from the better known fluke Schistosoma.  But unlike Schistosoma, the cercariae do not burrow into the skin of their primary hosts but rather encyst on grasses and vegetation.  And the cysts must be eaten by the primary host to complete the life cycle.

Life cycle of Fasciola [6]

So, from the standpoint of the fluke, the best environment would be a pasture cycling wet to dry, inhabited by an amphibious lymnaeid that might be exposed to swimming miracidia and shed swimming cercariae during the wet season, then drying so that the cysts might be grazed over by livestock.  Remember that.  That will be a key to understanding the remainder of this essay, and next month’s as well.

 

Liver flukes are a problem for the livestock industry [5] on six continents, and significant research efforts have been directed toward understanding the crappy little amphibious lymnaeids that host them worldwide for many years [7].  Except in the Pacific Northwest.  Where there is not a worker in the field today – not malacologist, nor parasitologist, nor veterinarian, nor guardian of the public health – who could identify a bona fide Lymnaea (Galba) bulimoides if it bit him on the boot toe.  Or at least, that was my hypothesis, as I boarded Delta Flight 954.

 

My library and museum research over several years previous had revealed to me what appeared to be repeated and systematic confusion between Lymnaea (Galba) bulimoides and Lymnaea (Galba) cubensis/viator, a similarly small, similarly amphibious, similarly susceptible lymnaeid much more widely distributed across The Americas, North and South [8].  That confusion seemed to have its origins in the late 19th century, redoubling in the early 20th, with the description of Lymnaea (Galba)  cockerelli, a third distinct biological species sometimes co-occurring with bulimoides in mixed populations [9].

 

I became convinced of a widespread, systematic, three-way confusion in early 2024 but had no evidence to support it, much less solve the problem.  To test that hypothesis, I needed a control, and none was to be had.  Thomas Nuttall’s original sample, surviving the perilous voyage around The Horn with their collector, was described by Isaac Lea as simply coming from “Hab. Oregon.”  In 1841, “Oregon” included all or part of five U.S. States, and much of British Columbia.

 

So, the first step out of the darkness, it seemed to me as I settled into my narrow seat early that July morning, would be to restrict the type locality of Lymnaea bulimoides to some more precise spot.  And then to sample and characterize the population of crappy little, amphibious lymnaeids inhabiting that spot as a standard, against which all other populations of lymnaeids might be compared.

The ideal type locality should be well-characterized, accessible, and protected.  Thus, folded in my shirt pocket that morning was a map of Oregon I had printed off line with a pin dropped on 44.5229, -123.3377, a drainage ditch by Bellfountain Road about 8 km SW of Corvallis where, as best I could figure, one Greg R. Foster had conducted the only decent studies of the biology of L. bulimoides ever published in the scientific literature, way back in 1969.  More about those studies [10] next month.

 

And there were other pins dropped on my map as well.  In addition to establishing a type locality, I very much wanted to find at least two additional populations of bona fide L. bulimoides to get some feel for intraspecific variation – one north of Corvallis, and one south.  For the former, I had researched online quite a few museum collections of apparently bona fide L. bulimoides in the Portland area, perhaps 70 miles north of Corvallis. And I had also marked the bowl of a rolling hayfield in a lovely and remote corner of Yamhill County about 40 miles north of Corvallis, locality courtesy of Ms. Courtney Hendrickson of Oregon State University, and the hero of our story, Mr. William (Bill) Gerth.

 

Bill is a senior faculty research assistant in the OSU Department of Fisheries, Wildlife, and Conservation Sciences in Corvallis, and a longtime friend of the FWGNA Project.  I could not name a cheerier or more enthusiastic colleague.  I had emailed Bill several days before flying off to Oregon, just to touch base, and he replied almost immediately with a gang of students and coworkers on the CC line all interested and eager to help.

 

And attached to his email was the jpeg that opened this essay, depicting a nice individual L. bulimoides collected by Ms. Hendrickson from a seasonal pond in a hayfield on the Gahr Farm property in Yamhill County. The itinerary I had outlined for myself and my lovely wife Shary, as we retrieved our luggage in the Portland airport and headed for the rental cars that hot July morning, was an ambitious one.

We drove north over the Columbia River that very afternoon, and into the state of Washington.  And my first noteworthy observation was made while still battling the urban sprawl of Vancouver: a population of very ordinary-looking Lymnaea (Galba) humilis inhabiting the muddy margins of a retention pond across Mill Plain Blvd from the Walmart (A).  I don’t suppose I was terribly surprised.  Those things are the Physa acuta of the Lymnaeidae.  But it was interesting to see our old friend humilis here in the Pacific Northwest, making cozy with the much more mysterious bulimoides I hoped to find, and the cubensis I rather hoped I would not.

 

The environment turned more propitious at Grass Valley Slough (B), but here we encountered the problem that would bedevil us for the remainder of our sojourn in the Pacific Northwest.  The slough was bone dry, baked hard as a rock.  I was most impressed by the dramatic accumulation of bleached Physa gyrina shells in the brittle mud at the culvert under Bybee Road, but finding no evidence of lymnaeid remains among them, neither shell nor meat, moved on.

 

Further north the topography evolved into rolling hills, the drainage improved, and scattered forest appeared.  And at point (C) I made an observation that forever changed my life [11].  Juga in a ditch.  This was a little roadside ditch, not three feet across, choked with grass, a place one would never expect to find a prosobranch gastropod of any sort back East, ever [12].  Yet Juga [14] does.  There simply is no substitute for field experience if one wants to understand the biology of a study organism, or indeed an entire Linnaean Family of study organisms, and I was once again reminded, harshly, that in the Pacific Northwest, I had none.

 At Battleground Lake (D) we reached the foothills of the Cascades, and finding the poorly drained fields and open pasturelands that best serve as habitat for the elusive L. bulimoides essentially gone, and the light failing, reversed our course for Portland, disappointed.  Tomorrow, I hoped, conditions might be more favorable.

Shary at Baker Cabin

The next morning we set our course east along the left bank of the Columbia River, swooping wide around the eastern suburbs of Portland toward the Willamette River valley to the south.  The freshwater gastropod fauna was gratifyingly diverse in the sloughs along the south bank of the big river (E), that of Kelly Creek (F) and several other sites in the Sandy and Clackamas River Valleys (G), rather less so [16].  My goodness, the day was turning hot.

 

All of the sites we visited that morning, and into the early afternoon, included some exposed mud bank, which would have been fine habitat for crappy little amphibious lymnaeids in The East but seemed devoid of molluscan life here in the environs of Portland.  We ran into the Oregon Trail at the historic Baker Cabin (H) and followed the trail down to its terminus at Oregon City (I).

 

Well, to be technical, Oregon City was the terminus of the Barlow Road section, a passage through The Cascades that did not open until 1846.  Thomas Nuttall pioneered the newly opening trail in 1834.  In those days the only route to Oregon was down the Columbia River, through the treacherous rapids at The Dalles.

 

My wife and I, on the other hand, opted to take I-205 and OR-18 south through the rich agricultural landscape of Yamhill County, now dry and brown in the August sun. The rotating sign in front of the bank was reading 103 degrees at 4:20 in the afternoon, when we passed through McMinnville on our way west toward Gahr Farm (J).

Bill’s colleague Courtney had thoughtfully alerted the landowner to expect visitors that afternoon and sent me a link to a map with a suggestion on a parking spot, as well as the precise coordinates [17] where she had collected N = 2 L. bulimoides in the spring of 2023, some 400 meters south through Farmer Gahr’s stubbly hayfield.  She added somewhat cryptically, however, “Just a heads up that the ponds can be a little tricky to find.”

 

My standard wardrobe for fieldwork is built on a foundation of hip boots over blue jeans, at least as much to protect my legs stomping though underbrush on my way to the creek as to protect my piggies upon arrival.  But the sun beat so mercilessly on Farmer Gahr’s fallow fields late that afternoon I changed into shorts and water shoes by  the desolate roadside, willing to pay the cost of few degrees of cooling in blood from my ankles.  And off I stomped toward an island of cattails flickering in the distance.

Alas, dry-rooted cattails were the only evidence that any pond had ever existed in the rolling hills of the Gahr Farm on August 1, 2024.  I staggered, dazed, from patch to patch, beating down through the willows to the Muddy Creek ditch, finding not puddle, nor pebble, nor polliwog.  The singleton bleached shell of Physa gyrina I ultimately recovered, in over an hour of pawing through brittle cane and cattail root, felt like a trophy.

Gahr Farm, 1Aug25

As I trudged back to our rental car, where my wife sweltered in the late afternoon sun [18], singleton Physa rattling dry in a vial in my chest pocket, I found myself meditating on the mantra, “Malacology in The West is different.”  And as the sun set on that exceptionally long, exceptionally hot day, southbound on OR-99W with Corvallis lit green on our GPS, a question crystallized.  Might any better fortune await me in Greg R. Foster’s ditch on the morrow?  Tune in next time.

Notes

 

[1] Most of the biographical information that opened this post came from:

• Nelson, John R. (2015) Thomas Nuttall: Pioneering Naturalist (1786 – 1859).  Bird Observer 43: Article 2.

[2] By remarkable coincidence, Richard Henry Dana was serving as an ordinary sailor on this very voyage, later to record the adventure in his famous memoir, “Two Years Before the Mast.”

 

[3] For a brief bio of “The Nestor of American Naturalists,” see:

• Isaac Lea Drives Me Nuts [5Nov19]

[4] Lea initially described Lymnaea bulimoides in brief Latinate form in 1841, with more complete English description in 1844:

• Lea, I (1841) On fresh water and land shells (continued).  Proceedings of the American Philosophical Society 2(17): 30 – 34.
• Lea, I. (1844/46) Continuation of Mr. Lea’s paper on fresh water and land shells.  Transactions of the American Philosophical Society 9(1): 1 – 31.

[5] Human cases of fascioliasis are becoming more common, according to the WHO website on neglected tropical diseases.  Transmission is apparently by ingestion of watercress or mint, although “encysted larvae may be found on other salad vegetables.”

 

[6] From the U.K. National Animal Disease Information Service [Nadis.org.uk]

 

[7] My sheaf of research papers on Galba worldwide fills an entire drawer of my filing cabinet.  For an opening into the vast literature, you might start with:

• The Lymnaeidae 2012: Fossarine Football [7Aug12]
• The American Galba and The French Connection [7June21]
• Exactly 3ish American Galba [6July21]
• What Lymnaea (Galba) schirazensis is not, might be, and most certainly is [3Aug21]

[8] For a review of the bulimoides/cubensis confusion, see:

• What is Lymnaea bulimoides? [13Feb24]

[9] For a review of the bulimoides/cockerelli confusion, see:

• Lymnaea (Galba) cockerelli, Number 15. [12Mar24]

[10] Greg R. Foster’s contributions:

• Foster, G.R. (1971)  Winter vagility of the aquatic snail Lymnaea (Galba) bulimoides Lea.  Basteria 35: 63 – 72.
• Foster, G.R. (1973) Soil type and habitat of the aquatic snail Lymnaea (Galba) bulimoides Lea during the dry season Basteria 37: 41 – 46.

[11] No, not really.  I’m straining to create some sort of drama out of parking by a weedy ditch in a rented Acura.  Work with me here.

 

[12] Well OK, the water was cool, and there was a little bit of current.  Melanoides populations can reach great densities in such ditches down in Florida [13].  But the point I’m trying to make is that pleurocerid gastropods do not live in such environments, under any circumstance, period.

 

[13] And Pomacea too, if you want to quibble.  Ditches are different in Florida.  See halfway through my essay:

• The Mystery Snail Color Genetics Project [6June23]

[14] I would have identified this population as Juga hemphilli, but opening the 2022 revision by Strong and colleagues [15] it appears that hemphilli has been synonymized under Juga plicifera.  I really need to dig into that paper.  Perhaps in a future post.

 

[15] Strong, Ellen E., J.T. Garner, P.D. Johnson, and N. V. Whelan (2022) A systematic revision of the genus Juga from fresh waters of the Pacific Northwest, USA (Cerithioidea, Semisulcospiridae).  European Journal of Taxonomy 848: 1 – 97.

 

[16] In the Columbia Slough Natural Area (E) I recorded Cipangopaludina chinensis, Physa acuta, Helisoma trivolvis, Lymnaea auricularia, and Gyraulus parvus.  At Kelly Ck (F) just Physa acuta.  At the Clackamas River (G) I recorded Juga plicifera, Fluminicola virens, and Physa acuta.

 

[17]  045.1666690, -123.3129760, to be quite precise.

 

[18] Throughout the day, my long-suffering wife had been chauffeuring me around NW Oregon like a poodle and patiently waiting for me in the car, reading a book, with the motor running and the AC on.  At some point during my lengthy explorations at the Gahr Farm, a public-spirited citizen stopped to warn her about the hazards of parking a car at idle over a grass stubblefield as dry as Farmer Gahr’s.  She cut the engine immediately, of course.  But was a bit on the cranky side when I eventually returned.

 

Taxonomy of the Pleurocera laqueata/troostiana complex. Part II, Ly - Z. Or, Just 974 Starfish Left to Go.

Editors note – This is the fifth (and final) installment of a series I started way back in September of 2024, starring Pleurocera laqueata with P. troostiana and P. simplex in supporting roles.  If you have a serious interest in the evolution and systematics of the North American Pleuroceridae, you might want to go down to footnote [1] and refresh your memory of previous episodes before proceeding.  If you are not interested in pleurocerid snails, on the other hand, I cannot imagine how the essay that follows could be much more than an irritation.

We opened last month’s essay with a tally of the pleurocerid nomina that Calvin Goodrich [2] recognized as valid to describe representatives of his Groups of Goniobasis catenaria and Goniobasis laqueata in the Ohio, Cumberland, and Tennessee River systems.  We observed that there  are 25 such names and reviewed the first 12 of them (alphabetically), promising to finish the job this month.

I did not mention it at the time, because it is a bit embarrassing, but I have found one Latin nomen useful for certain pleurocerid populations of the greater Ohio River basin that Goodrich synonymized under something else, and hence was not listed by him in 1940.  So, the total is actually 26 names, and we have 14 to review today.  Sorry – I know that’s going in the wrong direction, and I apologize.

Lyonii.  Isaac Lea [3] described Goniobasis lyonii in brief Latinate form from “Grayson County, Kentucky” in 1862.  Goodrich [2, 4] synonymized lyonii under Goniobasis laqueata and the nomen was carried passively (with a long list of other junior synonyms) into his Group of Goniobasis laqueata.  From there it disappeared, not mentioned at all by Burch [5], forgotten and consigned to the boneyard.

We consider the nomen lyonii valid and useful at the subspecific level [6], Pleurocera troostiana lyonii (Lea 1862), identifying laqueata/troostiana hybrids at the western and northern limits of the phenomenon. For our rationale, together with a copy of Lea’s [7] original figure and a modern topotype, see Dillon [8] pp 81 – 88 or my essay of [6July20].  An image of the holotype (USNM119147) is collected below.

USNM119147 (23.1 mm), MCZ53965 (17.3),
USNM118923 (13.6), USNM118429 (20.1)

Nassula. Timothy Abbot Conrad [9] described Melania nassula in 1834 from “the limestone spring at Tuscumbia, Alabama.”  Goodrich [2, 4] considered that the taxon named a distinct and valid species in his Group of Goniobasis catenaria; Burch followed suit in his Elimia catenaria Group.

No original type material seems to have survived, according to Graf [10], although the MCZ holds the “possible syntype” figured above (MCZ 53965).  And a pleurocerid population matching Conrad’s original 1834 description and figure (#9 below) quite well still inhabits the Tuscumbia Big Spring to the present day.  It does, indeed, look very much like an Atlantic drainage (or Floridian) population of Pleurocera catenaria has been airlifted 300 miles west and dropped into North Alabama.  This is a distinct and valid biological species, Pleurocera nassula (Conrad 1834).

Paupercula.  Isaac Lea described Goniobasis paupercula in brief Latinate form in 1862 [3], giving the type locality as “North Alabama, Prof. Tuomey,” with a more complete English description and figure following in 1863 [7].  Goodrich [2,4] recognized it as a valid species in his “Group of Goniobasis laqueata,” as did Burch [5] in his “Elimia laqueata group.”

We consider the nomen a junior synonym of Pleurocera troostiana perstriata (Lea 1853) [11], identifying laqueata/troostiana hybrids with decollate shells in North Alabama.  For our rationale, together with a copy of Lea’s [7] original figure and images of two topotypes (an adult and a juvenile, both R), see Dillon [8] pp 61 – 71 or my essay of [10May20].   An image of the holotype (USNM 118923) is collected above.

Perstriata. Isaac Lea [11] described Melania perstriata from “Coosa River, Alabama, Prof. Brumby, Huntsville, Tenn., Mr. J. Clark” in 1853.  Goodrich [2, 4] recognized it as a valid species in his “Group of Goniobasis laqueata,” restricting its type locality to the Big Spring at Huntsville, Alabama.  Burch [5] concurred on the specific value of the nomen but transferred it to his “Elimia catenaria group.”  We consider the nomen valid at the subspecific level, Pleurocera troostiana perstriata, identifying laqueata/troostiana hybrids with little or no costation on the body whorl.

For our rationale, together with a copy of Lea’s [11] original figure, an image of a modern topotypic specimen, and example shells from several additional populations, see Dillon [8] pp 51 – 59 or my essay of [15Apr20].  An image of the holotype (USNM 118429) is collected above.

From Conrad [9], Lea [16], Lea [7]

Plicata-striata.  Albert G. Wetherby’s [12] 1876 description of Goniobasis plicta-striata [13] is very difficult to obtain today.  But Walker [14] quotes his type locality as “Stone River and Mill Creek, Rutherford County, and Sinking Creek, Shelbyville, TN.”  Goodrich [2] assigned the nomen to his Group of Goniobasis laqueata.  Burch re-spelled the nomen without the dash and shifted it to his Elimia catenaria group. 

The entire main stem of the Stones River is impounded today, as is Mill Creek, but Sinking Creek is inhabited by apparently healthy populations of both P. laqueata and P. troostiana edgariana, not especially helpful for our understanding of Wetherby's taxon today.  

Fortunately, Wetherby donated N = 65 paratypes “ex original lot” to Harvard’s Museum of Comparative Zoology (MCZ 149453).  Unfortunately, that entire lot of shells is dead collected, worn, and bleached – the poorest excuse for type material I have ever seen preserved in any collection, in my entire 50 years of professional experience. 

I have some insight into the origin of this problem, although I cannot explain it.  Several years ago I myself was quite stricken by a gigantic bed of relic pleurocerid shells at the bottom of Bradley Creek, a tributary of the East Fork Stones River near Lascassas.  The photo below, taken through about an inch of gently flowing water, shows thousands of P. laqueata shells, primarily, with scattered troostiana hybrids, all in various stages of decomposition.  Why Albert G. Wetherby would paw through such a bed, select 65 and describe them as “Goniobasis plicata-striata” is beyond me.

An obliging curatorial assistant at Harvard's MCZ [15] selected two shells from lot 149453 as exemplars to photograph for their online catalog at my request, offering seven images of the two shells from various angles. The best of those seven images is reproduced down below.  From some angles, it is possible to make out, just barely, weak plications on the top half of the shell I have figured.  I cannot find evidence any striation on either exemplar shell at any angle photographed.

Therefore, Goniobasis plicata-striata (Wetherby 1876) appears to be a simple junior synonym of Pleurocera laqueata laqueata (Say 1829) [28].

Bradley Creek, TN

Porrecta.  Isaac Lea [16] described Goniobasis porrecta in brief Latinate form from “Gap Creek and Spring” (Cumberland Gap, TN) in 1863, with more complete English description and figure (#47 above) in 1866 [17].  Goodrich [2] considered it a valid species in his “Group of Goniobasis catenaria,” subsuming vittatella (Lea 1863) under it, as did Burch [5] in his “Elimia catenaria group.”

We consider the nomen a junior synonym of Pleurocera troostiana troostiana (Lea 1838).  For our rationale, together with an image of a modern topotype, see Dillon [8] pp 1 – 7 or my essay of [4Aug19].  An image of the holotype (USNM 118834) is collected below.

Pybasii.  Isaac Lea [3] published a brief Latinate description of Goniobasis pybasii from “Tuscumbia, Alabama” in 1862, with English description and figure following in 1863 [7].  This is the third of Lea’s 1862/63 “eighty-two new species” of Goniobasis we have reviewed in the present essay, along with lyonii and paupercula, all synonyms of the same species.  A nineteenth-century malacological hat trick!  There will be two more.

Goodrich [2, 4] recognized pybasii as a valid species in his “Group of Goniobasis laqueata,” as did Burch [5] in his “Elimia laqueata group.”  We consider the nomen a junior synonym of Pleurocera troostiana perstriata (Lea 1853), identifying laqueata/troostiana hybrid populations in North Alabama.  For our rationale, together with a copy of Lea’s [7] original figure and an image of a modern topotypic specimen (Q), see Dillon [8] pp 61 – 71 or my essay of [10May20].   An image of the holotype (USNM 119329) is collected below.

MCZ149453 (16.1 mm), USNM118834 (17.7 mm),
USNM119329 (19.8 mm), USNM119296 (16.9 mm)

Rubella.  This is the fourth of the “eighty-two new species” that Isaac Lea [3] described in 1862 we have reviewed this afternoon.  Lea’s original figure [7] is reproduced above (#191), as well as a fresh image of the holotype (USNM 119296).

Goodrich [2] considered rubella a valid species in his “Group of Goniobasis catenaria,” noting as he did, however, that the species was “reported originally from Cherokee County, North Carolina, and not found there since.  May be the same as porrecta.”  Burch [5] did not list rubella but did reproduce Tryon’s figure of it (#369), with the caption “E. rubella = ?E. porrecta.”

Right.  Lea’s original description, “very near to Melania (Goniobasis) teres but differs in being carinate,” together with his figure and type specimen, make it quite clear that Goniobasis rubella, like porrecta and like teres, is a simple junior synonym of Pleurocera troostiana troostiana (Lea 1838).

That said, I really think that the type locality given by Lea for his G. rubella, “Near Murphy, Cherokee County, North Carolina,” must have been in error.  The modern range of P. troostiana does not extend any further east up the Hiwassee drainage than Polk County, TN.

Spinella.  The fifth of Isaac Lea’s 1862/63 creations [3, 7] we have reviewed this month, Goniobasis spinella was described from “Sycamore, Claiborne County, Tennessee” as “very nearly of the same outline of Melania (Goniobasis) strigosa but much smaller, slimmer, and darker color.”  Goodrich [2] considered the nomen a subspecies of Goniobasis arachnoidea in his “Group of Goniobasis catenaria,” as did Burch [5] in his “Elimia catenaria group.”

Lea’s original figure is reproduced way down below (#130), and his holotype (USNM 119269) freshly imaged immediately below.  We consider spinella another simple junior synonym of Pleurocera troostiana troostiana (Lea 1838).  For our rationale, together with an image of a modern topotype, see Dillon [8] pp 41 – 49 or my essay of [7Jan20].

USNM119269 (16.3 mm), USNM118448 (14.2 mm),
USNM121603 (19.4 mm)

Striatula.  Isaac Lea [18] described Melania “striata” in brief Latinate form from “Tennessee” in 1841, with English description and figure following in 1843 [19].  He amended the name to “striatula” in the interim [20].  Goodrich [2] considered striatula a valid species in his “Group of Goniobasis catenaria,” as did Burch [5] in his “Elimia catenaria group.”

Lea’s original [19] figure (#49) is reproduced below, and a shell catalogued into the USNM collection as the holotype (USNM 118448), that Graf [10] referred to as a “possible syntype” is imaged above.  They do not match.  Rats.

Lea’s original figure showed strong striation and no plication, looking like a synonym of typical P. troostiana troostiana, as I myself suggested in Dillon [8] pp 41 – 49 and in my essay of [7Jan20].  The nominal holotype, however, shows plicae as strong as striae [21], looking very much like P. troostiana edgariana.  And the locality information, simply “Tennessee,” is no help resolving the discrepancy.

Turning to the letter of Lea’s [18] original description as a tiebreaker, we read “shell striate” to lead off, with no mention of plication.  But in Lea’s remarks, we read “In some individuals the folds are numerous – in others the striae predominate and cover nearly all the whorls.”  Are the “folds” plicae?

In the end, I suppose it does not matter.  Melania striatula (Lea 1842) is a junior synonym of Pleurocera troostiana (Lea 1838), but whether of the purebred (typical) form or the hybrid edgariana form, I don’t think we’ll ever know.

Strigosa. Another of Isaac Lea’s 1841/43 classics [18,19], Melania strigosa was described as “somewhat like the teres herein described” from “Tennessee, Dr. Troost, Holston River Dr. Warder.”  Goodrich [2] considered it a valid species in his “Group of Goniobasis catenaria,” as did Burch [5] in his “Elimia catenaria group.”

In my 2023 essay [8, pp 41 - 49], and in the 2020 blog post from which that essay was crafted [7Jan20], I offered four reasons to restrict the strigosa type locality to Little Flat Creek 10 miles north of Knoxville, figured a topotype, and reproduced Lea’s [19] original figure.  Lea’s holotype (USNM 121603) is imaged above.  We consider the nomen yet another simple junior synonym of Pleurocera troostiana troostiana (Lea 1838).

From Lea [7], Lea [19], Lea [22]

Teres.  And a third time.  Isaac Lea [18] described Melania teres from “Tennessee, Dr. Troost” in 1841, following with a more complete English description and figure in 1843 [19].  Again, Goodrich [2] considered it a valid species in his “Group of Goniobasis catenaria,” as did Burch [5] in his “Elimia catenaria group.”

We considered the locality data too vague to send us on a modern day teres-hunt for our blog post of [7Jan20] or the essay [8, pp 41 - 49] derived from it, but did reproduce both Lea’s [19] original figure, and figure #356 from Burch [5].  An image of Lea’s holotype (USNM 119251) is collected below.  We consider the nomen yet another simple junior synonym of Pleurocera troostiana troostiana (Lea 1838).  So, it materializes that Isaac Lea scored malacological hat tricks in both 1841 and in 1862.  Without question, Isaac Lea was the greatest of all time, of something.

Torta/tortum.  Isaac Lea’s brief, Latinate description of Melania torta from “Big Creek, Lawrence County, Tennessee” was published in 1845 [22], with more complete English description and figure following in 1848 [23].  Tryon [24] assigned the nomen to Pleurocera in 1873, changing the spelling to tortum [25].  Goodrich considered tortum a valid subspecies of Goniobasis laqueata, as did Burch, of Elimia laqueata.

Lea’s original [23] figure is reproduced above (#30), and a fresh image of the holotype (USNM 119255) collected below.  Quoting him verbatim:

“There were eight specimens of this species submitted to my examination by Mr. Clark, of Cincinnati.  […] The apices of the individuals now before me are slightly eroded … one of the specimens has small folds near the apex, with decussating striae. […] The body whorl is very long.”

Lea’s description, original figure, and designated holotype all strongly suggest that Melania torta is a laqueata/simplex hybrid, making the nomen a junior synonym of populations we designated Pleurocera laqueata castanea (Lea 1841) in our essay of [12Nov24].

Lawrence County, Tennessee, is on the Alabama line just north of Florence in the Shoal Creek subdrainage.  I cannot find a “Big Creek” anywhere on modern maps, but Pleurocera laqueata populations bearing shells of typical morphology are widespread in that county.  And the FWGNA database contains five records of P. laqueata castanea in Lauderdale County, AL, just south.

USNM119251 (21.6 mm), USNM119255 (18.0 mm),
USNM119256 (25.3 mm)

Troostiana.  Isaac Lea [26] described Melania troostiana from “Mossy Creek, Jefferson County, Ten” in 1838, quite early in his career.  Goodrich [2] considered it a valid species in his Group of Goniobasis catenaria, as did Burch [5] in his Elimia catenaria group.

Pleurocera troostiana is the oldest name for a distinct, valid, biological species of pleurocerid snail widespread in small streams of the greater Ohio drainage from SW Virginia through most of Tennessee, North Alabama and Southern Kentucky.  For a complete review, illustrated with a copy of Lea’s [26] original figure and images of modern topotypes, see Dillon [8] pp 35 – 40 or my essay of [9Dec19].  An image of the holotype (USNM 119256) is collected above.

I provided a photo of a living P. troostiana individual in my follow-up essay of [7Jan20], published in Dillon [8] pp 41 – 40.  I then developed the argument that a great variety of pleurocerid nomina in East Tennessee might be junior synonyms, including arachnoidea, porrecta, spinella, strigosa, striatula, and teres, as reviewed above.

Then in a series of four essays posted on this blog between April and July of 2020, and published in 2023 by Dillon [8] pp 51 – 88, I recognized three subspecies [6] of P. troostiana inhabiting the waters of North Alabama, Middle Tennessee, and Kentucky: perstriata (Lea 1853), edgariana (Lea 1841), and lyonii (Lea 1862), synonymizing a large number of additional nomina underneath them.  I also published a separate circular [27] reviewing the entire four-subspecies system, including the typical (s.s.) form.

So, we closed last month’s essay with a reference to the sanctimonious story usually entitled “Starfish on the Beach,” which seems to have evolved from a 1969 essay by Loren Eiseley.  Including the 12 starfish we dispatched last time, our two-month total is 26 starfish on the beach, 7 of which we tossed back into the sea.  At the species level we recognize laqueata, troostiana, and nassula.  At the subspecies level, all of hybrid origin, we recognize perstriata, edgariana, and lyonii under troostiana and castanea under laqueata.  The other 19 starfish we have now bagged for the dumpster.  Just 974 starfish left to go.

Postscript:

On 10Feb25 this essay was combined with four companion pieces and published as a pdf separate entitled, "Systematic review of the Pleurocera laqueata/troostiana complex."  That document is available for download as FWGNA Circular No. 8.

Notes:

[1] Here are the four essays on the Pleurocera laqueata/troostiana complex that preceded the present:

• The type locality of Melania laqueata [18Sept24]
• Widespread hybridization between Pleurocera laqueata and P. troostiana in streams of the Tennessee/Cumberland [15Oct24]
• Reticulate evolution in the North American Pleuroceridae [12Nov24]
• The taxonomy of the Pleurocera laqueata/troostiana complex.  Part I, A – La. [10Dec24]

[2] Goodrich, C. (1940) The Pleuroceridae of the Ohio River drainage system.  Occasional Papers of the Museum of Zoology, University of Michigan  417: 1-21.

[3] Lea, Isaac (1862) Description of a new genus (Goniobasis) of the Family Melanidae and eighty-two new species. Proceedings of the Academy of Natural Science of Philadelphia 19: 262 – 272.

[4] Goodrich, C. (1930)  Goniobases of the vicinity of Muscle Shoals.  Occasional Papers of the Museum of Zoology, University of Michigan 209: 1 – 25.

[5] 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).

[6] Subspecies are populations of the same species in different geographic locations, with one or more distinguishing traits.  For more, see:

• What is a subspecies? [4Feb14]
• What subspecies are not [5Mar14]

[7] Lea, Isaac (1863) New Melanidae of the United States.  Journal of the Academy of Natural Sciences of Philadelphia (New Series) 5: 217 – 356.

[8] Dillon, R.T., Jr. (2023b) The Freshwater Gastropods of North America Volume 6, Yankees at The Gap, and Other Essays.  FWGNA Project, Charleston, SC. [publications]

[9] Conrad, T. A. (1834) New Fresh Water Shells of the United States, with coloured illustrations, and a monograph of the genus Anculotus of Say; also A synopsis of the American naiades.  Philadelphia, Judah Dobson.  76 pp, 8 plates.

[10] Graf, D. L. (2001) The cleansing of the Augean stables.  Walkerana 12(27): 1 - 124.

[11] Lea, Isaac (1853)  Description of a new genus (Basistoma) of the Family Melaniana, together with some new species of American Melaniae.  Transactions of the American Philosophical Society (new series) 10: 295 – 302.

[12] We first met Albert G. Wetherby (1833 – 1902), author of the baffling taxon Helisoma duryi, back in 2020:

• The flat-topped Helisoma of The Everglades [5Oct20]

[13] Wetherby, A.G. (1876) Remarks on the variation in form of the family Strepomatidae, with descriptions of news species  Proceedings of the Cincinnati Society of Natural History 1:10.

[14] Walker, B. (1918)  A synopsis of the classification of the freshwater Mollusca of North America, North of Mexico, and a catalogue of the more recently described species, with notes.  Univ. Mich. Mus. Zool. Misc. Publ. 6: 1 - 213.

[15] The assistance of Ms. Melissa Merkel, curatorial assistant in the Malacology Department at Harvard's Museum of Comparative Zoology, is gratefully acknowledged.

[16] Lea, Isaac (1863) Descriptions of fourteen new species of Melanidae and one Paludina.  Proceedings of the Academy of Natural Sciences of Philadelphia 15: 154 – 156.

[17] Lea, Isaac (1866) New Unionidae, Melanidae, etc. chiefly of the United States.  Journal of the Academy of Natural Sciences of Philadelphia (New Series) 6: 113 – 187.

[18] Lea, Isaac (1841) Continuation of Mr. Lea's paper on New Fresh Water and Land Shells.  Proceedings of the American Philosophical Society 2: 11 – 15.

[19] Lea, Isaac (1843) Description of New Fresh Water and Land Shells.  Transactions of the American Philosophical Society (New Series)  8: 163 – 250.

[20] Lea, Isaac (1842) Minutes of the Stated Meeting of December 2.  Proceedings of the American Philosophical Society 2: 237.

[21] If you are confused about striation and plication (costation), see my 2020 essay for a diagram:

• Huntsville Hunt [15Apr20]

[22] Lea, Isaac (1845) Descriptions of new fresh water and land shells.  Proceedings of the American Philosophical Society 4: 162 – 168.

[23] Lea, Isaac (1848)  Description of new fresh water and land shells.  Transactions of the American Philosophical Society 10: 67 – 101.

[24] Tryon, G. W. (1873) Land and Freshwater shells of North America Part IV, Strepomatidae.  Smithsonian Miscellaneous Collections 253: 1 - 435.

[25] At the risk of confusing the situation further.  Isaac Lea also described a Trypanostoma tortum in 1862 from the Uchee River (Creek), a tributary of the Chattahoochee on the GA/AL border.  That one was renamed Pleurocera parkerii by Tryon.

[26] Lea, Isaac (1838-39) Description of New Freshwater and Land Shells.  Transactions of the American Philosophical Society (New Series) 6: 1 – 154.

[27] Dillon, R.T., Jr.  (2020) The four subspecies of Pleurocera troostiana (Lea 1838), with synonymy.  FWGNA Circular 2: 1 - 5. [pdf]

[28] In the original version of this blog, as posted 14Jan25, I ventured to hypothesize that Weatherby’s plicata-striata was a junior synonym of Pleurocera troostiana edgariana (Lea 1841).  That was before I saw the MCZ paratypes.  On 10Feb25, I changed my mind.

Taxonomy of the Pleurocera laqueata/troostiana complex. Part I, A - La.

Editor’s Note – This the fourth installment of a five-part series on Pleurocera laqueata, P. troostiana, and hybridization between them in small streams of Kentucky, Tennessee, and North Alabama.  If your interest in the evolution of the North American Pleuroceridae is serious enough to have dropped you this deep into so dismal a swamp, and you have not previously read my posts of [18Sept24], [15Oct24] and [12Nov24], go back and do so now.  We will wait for you.

Calvin Goodrich [1] divided the Goniobasis species of the Tennessee, Cumberland, and Ohio River systems into six groups [2]. Prominent among those was a “Group of Goniobasis laqueata,” with ten species and six subspecies, and a “Group of Goniobasis catenaria” with eight species and one subspecies.  Unsurprisingly, most of the nomina in that former group are synonyms of Pleurocera laqueata (Say 1829), and most of the latter group synonyms of Pleurocera troostiana (Lea 1838).

But because P. laqueata and P. troostiana hybridize, the distinction between Goodrich’s two groups has never been clear.  Burch [3] moved three species with two subspecies from Goodrich’s Group of Goniobasis laqueata to his understanding of the “Elimia catenaria Group” and separated one species/subspecies pair from Goodrich’s laqueata group (the “Elimia acuta Group”) as entirely distinct.

So, working alphabetically, this month we will review the first twelve of the 10 + 6 + 8 + 1 = 25 pleurocerid nomina from the Ohio, Cumberland and Tennessee allocated by Calvin Goodrich to his Groups of Goniobasis catenaria and Goniobasis laqueata combined.

USNM119088 (14.9 mm), MCZ50236 (21.1 mm),
USNM119217 (13.5 mm)

The vast majority of these were described by our old buddy Isaac Lea [4], in eight separate papers and monographs published between 1831 and 1868.  Lea described seven of the species we will review over the next two months (as “Melania”) in brief Latinate form in the Proceedings of the American Philosophical Society of 1841 [5], following with more complete English descriptions and figures in the APS Transactions of 1843 [6].  He disgorged an additional dose of seven brief Latinate descriptions (as “Goniobasis”) in the Proceedings of the Academy of Natural Sciences of 1862 [7], following with complete descriptions and figures in the ANSP Journal of 1863 [8].  Lea’s descriptions of the third set of seven species were scattered in other journals at other times.

This catalog may get a bit tedious at times, I’m afraid, involving a lot of rather dry library scholarship, and to be quite frank, is not the kind of thing I am especially good at, not having been blessed with the lawyerly frame of mind necessary to build any reputation in the marble halls of zoological nomenclature.  It’s a service, I suppose.

So, for a spoonful of sugar, last month I traveled up to Washington to see our good friend Ellen Strong of the USNM.  Ellen and her obliging staff set aside for me Isaac Lea’s type specimens [9] for 20 of the species that Goodrich included in his groups of catenaria and laqueata from the greater Ohio drainage.  This is the first time that photos of any of those types have ever been published, as far as I am aware.

And I contacted our good buddy Gonzalo Giribet up at the MCZ Harvard, and he and Ms. Jennifer Trimble agreed to add type specimens of Conrad’s nassula, Anthony’s arachnoidea, and Wetherby’s plicata-striata to their (rather lengthy) “imaging queue.”  And our friends at the ANSP, already on the ball, had previously uploaded and made available to the public a nice photo of Haldeman’s costifera.  Bottom line, over the next two months, we will publish fresh photos of type material for 24 of the 25 catenaria/laqueata group species in habiting the Ohio, Cumberland, and Tennessee River systems.  And offer a coherent, modern hypothesis for both their evolutionary and their taxonomic relationships.  Here we go:

Acuta.  First, we must be very clear about what the pleurocerid snail that Isaac Lea described as Melania acuta is not.  It is not that well-known inhabitant of rivers and streams of the Ohio, Great Lakes, and upper Mississippi drainages described as “Pleurocera acuta” by C.S. Rafinesque [11] in 1831, monographed in loving detail by Dazo [12] in 1965.  Rafinesque’s Pleurocera acuta was lowered to subspecific status under Pleurocera canaliculata by Dillon [13] in 2013.

Completely independent of whatever Constantine Smaltz Rafinesque was discovering and publishing in the early 19th century, on May 7, 1830 Isaac lea read a paper at a meeting of the American Philosophical Society in Philadelphia describing “Melania acuta” from the “Tennessee River, Prof. Vanuxem” bearing a shell whose “delicate form, furnished with undulations and transverse lines, will easily distinguish it.”  Lea’s little 1:1 figure is reproduced below.

From Lea [14], Anthony [20], Lea [22], Reeve [24]

A reading is not a publication, however.  The front page of Volume 4 of the Transactions of the American Philosophical Society, in which Lea’s paper was ultimately published [14], clearly states 1834.  N.P. Scudder [15] argues, however, that Lea’s paper was “issued in the latter end of 1831, and acknowledged by correspondents as received in that year, PANSP 7:243.”  Tryon [16] does not hazard a guess on Lea’s publication date, Goodrich [1] suggests 1830 and both Burch [3] and Graf [10] concur with Scudder’s 1831.

So, the bottom line is that Rafinesque’s acuta and Lea’s acuta seem to have been published simultaneously.  And since Lea’s acuta was reassigned to Goniobasis by Tryon [16], and then re-reassigned to Elimia by Burch [3], and then both Goniobasis and Elimia folded under Pleurocera by Dillon [17], today we have two Pleurocera acutas, both described in 1831, meaning entirely different things.

Rafinesque’s acuta became prominent, however, while Lea’s acuta receded into obscurity.  A big part of the reason is that Isaac Lea’s type locality was vague.  Goodrich [18] speculated that the that the “Tennessee River” from which Vanuxem sampled that first specimen of Lea’s acuta must have been in North Alabama, where specimens matching his description “have been taken at Muscle Shoals by Messrs. Hinkley and Smith.”  That malacologically rich section of the Tennessee River is long inundated and much lamented [19].  Goodrich also reported collections from the Flint River, the Elk River, and Piney Creek, but of course, tributaries are a poor substitute for the main river itself.

An image of the type specimen (USNM119088) was reproduced way up at the top of this blog post.  Rather than join the speculation on where that shell might have been collected, or whether the population of pleurocerid snails including the individual from the back of which it was snatched almost 200 years ago might have been reproductively isolated from any of the biological species of pleurocerids we recognize today, I will simply suggest that Melania acuta Lea 1831 is a junior homonym of Pleurocera acuta Rafinesque 1831.  RIP Melania (aka Goniobasis, aka Elimia) acuta.

Arachnoidea.  John G. Anthony [20] described Melania arachnoidea from “a small stream emptying into the Tennessee River near Loudon, Tennessee” in 1854.  Goodrich [1] considered it a valid species in his Group of Goniobasis catenaria, as did Burch [3] in his Elimia catenaria Group.  We consider the nomen a junior synonym of Pleurocera troostiana troostiana (Lea 1838).

For our rationale, together with an image of a modern topotype, see Dillon [21] pp 41 – 49 or my essay of [7Jan20].  See above for an image of a lectotype (MCZ50236) and a reproduction of Anthony’s original 1:1 figure.  We measured and scored a sample of N = 30 shells from Anthony’s arachnoidea type locality near Loudon for our troostiana regression analysis two months ago [15Oct24].

Castanea.  Isaac Lea’s brief Latinate description of Melania castanea (Maury County, Tenn. Thomas H. Dutton) was published in 1841 [5], with a more complete English description and figure following in 1843 [6].  Last month [12Nov24] I reproduced Lea’s original 1843 figure, concurring with Goodrich’s [1] suggestion that castanea is a valid subspecies Pleurocera laqueata castanea (Lea 1841), and advancing the hypothesis that pleurocerid populations bearing shells of that distinctive morphology are hybrids between P. laqueata and P. simplex.  A fresh image of the holotype, USNM119217, was reproduced in the figure that opened this essay way up above.

USNM121480 (10.2 mm), ANSP27434 (18.3 mm),
USNM119021 (19.3 mm), USNM118463 (14.1 mm)

Clavula.  Goniobasis clavula was described from “Jackson Co, Alabama, Dr. Spillman” by Isaac Lea [22] in 1868.  That county, in the extreme NE corner of Alabama, lies entirely within the Tennessee River drainage.  The nomen was demoted to subspecific status under Goniobasis acuta by Goodrich [1, 18] and placed in the Group of Goniobasis laqueata.  Burch [3] agreed with Goodrich about the subspecific relationship but transferred clavula along with its parent into a separate Elimia acuta Group.

Both Lea’s [22] original figure and a fresh image of the holotype (USNM121480) are reproduced above.  The type specimen is subadult, very slender, demonstrating both striation and plication, becoming obsolete on the body whorl.  We consider the nomen a junior synonym of the hybrid Pleurocera troostiana perstriata (Lea 1853).

Costifera.   Melania costifera was described in 1841 from “Hennepin, Illinois” by S. S. Haldeman [23].  The nomen was considered to represent a valid species by both Goodrich and Burch, in their Groups of Goniobasis laqueata and Elimia laqueata, respectively.  No figure was provided originally, but Haldeman’s written description “having numerous, spiral, elevated lines, crossing a series of curved ribs, on all the whorls,” together with the slender figure subsequently published by Reeve [24], reproduced above, sound very much like P. troostiana lyonii.

Haldeman’s original type shell (ANSP27434) is still held in the ANSP collection today, however, its image thoughtfully made available online by our friends in Philadelphia.  And that image, as reproduced above, suggests that the “spiral, elevated lines” are negligible, and the body whorl relatively large, as typical for Pleurocera laqueata laqueata.

In such a situation, where the published figure and the type shell are strikingly different, it would be nice to refer to a modern topotypic collection.  Alas, my review of the online catalog at the Illinois Natural History Survey returned no modern records of costifera, laqueata, troostiana, or any pleurocerid bearing a shell with plications or striations of any sort within 250 miles of Hennepin [25].  Absent a tiebreaker, therefore, the actual type shell as held by the ANSP must take precedence over the Reeve’s 1860 figure.  Melania costifera (Hald 1841) would appear to be a junior synonym of Pleurocera laqueata laqueata (Say 1829).

Costulata.  Melania costulata was described in 1841 by Isaac Lea [5] from the “Barren River, Kentucky.”  His 1843 figure [6] is reproduced below.  Goodrich [1] recognized the nomen as a subspecies of Goniobasis laqueata, as did Burch [3] of Elimia laqueata.

Lea wrote, “In its general characters this species resembles M. laqueata Say.  It may be distinguished in its being of less diameter and being more slender.”  The holotype shell (USNM119021) as freshly figured above is indeed a bit more slender than typical for laqueata.  But it demonstrates strong striations (not noted by Lea) as well as plications, extending down to include the body whorl.  We consider costulata a junior synonym of the hybrid taxon Pleurocera troostiana edgariana (Lea 1841).

From Lea [6], Lea [6], Lea [8].

Crispa.  Isaac Lea [7] described Goniobasis crispa from “Florence, Alabama” in 1862. The nomen was lowered to subspecific status under G. perstriata by Goodrich [1, 18] and placed with its parent in the Group of Goniobasis laqueata.  Burch [3] concurred with the demotion, but not the placement, transferring “Elimia perstriata crispa” to his Elimia catenaria Group.  We consider the nomen a junior synonym of Pleurocera nassula (Conrad 1834).  See Dillon [21] pp 61 – 71 or my essay of [10May20] for a copy of Lea’s [8] original figure.   A fresh image of the holotype (USNM118463) is collected above.

Curreyana.  Just as was the case of Melania costulata, Melania curryana was described by Isaac Lea [5] from the “Barren River, Kentucky” in 1841.  Lea’s 1843 figure of curreyana [6] is reproduced next to his figure of costulata above.  And again, as in M. costulata, Goodrich [1] recognized M. curryana as a valid nomen in his Group of Goniobasis laqueata, as did Burch [3] in his Elimia laqueata Group.

Unlike M. costulata, however, Graf [10] was unable to find any type material for curreyana in the USNM.  It would appear that Lea’s 1841 written description, together with his 1843 figure, are all we have for evidence today.

Lea wrote that the shell of M. curreyana was “Remarkable for large and strong folds,” adding “It is without striae, and the body whorl is smooth, except near the suture.”  Those contemporary observations, together with Lea’s figure of a shell absent any apparent striation, combine to suggest strongly that M. curreyana (Lea 1841) is a simple junior synonym of Pleurocera laqueata laqueata (Say 1829).

Decampii.   Isaac Lea [26] described Goniobasis decampii from “Huntsville, Alab.” in 1866.  He apparently intended to include the Latinate description in his paper of Mayish [27] 1863, because in his follow-up paper of 1866 he stated that his original description had been published three years earlier, but it was not.

The nomen was lowered to subspecific status under G. perstriata by Goodrich [1, 18] and placed with its parent in the Group of Goniobasis laqueata.  Burch [3] concurred with the demotion, but not the placement, transferring “Elimia perstriata decampii” to his Elimia catenaria Group.  We consider the nomen a junior synonym of the hybrid taxon Pleurocera troostiana perstriata (Lea 1853).

For our rationale, together with a copy of Lea’s [26] original figure, see Dillon [21] pp 61 – 71 or my essay of [10May20].   A fresh image of the very slender holotype shell (USNM118967), bearing light striations and plications on its upper whorls only, is collected below.

Edgariana. Isaac Lea [5] described Melania edgariana from “Cany Fork, Tenn.” in 1841.  Tryon [16] synonymized the nomen under Conrad’s (1834) nassula [28] but Goodrich [1] resurrected it as a valid species in his Group of Goniobasis laqueata.  Burch agreed on the specific status but transferred it to his Elimia catenaria Group.  We consider the nomen valid at the subspecific level, Pleurocera troostiana edgariana (Lea 1841), identifying laqueata/troostiana hybrids with strong sculpture on the body whorl.

USNM118967 (17.0 mm), USNM118423 (19.0 mm),
USNM118959 (17.5 mm)

For our rationale, together with a copy of Lea’s [6] original figure, an image of a modern topotypic specimen, and example shells from several additional populations, see Dillon [21] pp 73 – 79 or my essay of [5June20].   A fresh image of Lea’s holotype (USNM118423) is collected below.

Interveniens.  Isaac Lea [7] briefly described Goniobasis interveniens from “North Alabama, Prof. Tuomey” in 1862, with a more complete description and figure following in 1863 [8]. His original 1:1 figure and an image of the holotype (USNM118959) are reproduced above.  Both Goodrich [1, 18] and Burch [3] considered interveniens a valid and distinct species in their Groups of Goniobasis laqueata and Elimia laqueata, respectively.  We are at a loss to find any distinction between Lea’s interveniens and Thomas Say’s laqueata whatsoever, considering Goniobasis interveniens (Lea 1862) a simple junior synonym of Pleurocera laqueata laqueata (Say 1829).

Laqueata.  Melania laqueata was described by Thomas Say in 1829 from “Dr. Troost in Cumberland River” [29].  No original type material seems to have survived, although Say’s written description and figure were sufficient to establish it as the type for both Goodrich’s Group of Goniobasis laqueata and Burch’s Elimia laqueata Group.

Pleurocera laqueata (Say 1829) is the oldest name for a distinct, valid, biological species of pleurocerid snail widespread in rivers and streams of Middle Tennessee, North Alabama, and southern Kentucky.  We recognize three subspecies: the big river alveare (Conrad 1834) and the laqueata/simplex hybrid castanea (Lea 1841), as well as the typical (s.s.).  For a complete review, illustrated with a copy of Say’s [29] original figure and images of several modern topotypic shells, see my essay of [18Sept24].

Okay, twelve down.  Many of you, I feel sure, will have heard that saccharine story about the young girl who finds a million starfish washed up on the beach, and begins to toss them back, one at a time.  Along comes a man and asks her how she could possibly hope to save a million starfish.  And she flips another starfish into the sea and replies, “Well, I saved that one.”

So Dan Graf [10] catalogued over 1,000 pleurocerid nomina at the specific or subspecific level, washed up on the beach like starfish.  In this month’s essay we flipped three nomina back into the ocean (castanea, edgariana, laqueata), bagged nine others, and threw them into the dumpster.  Next month we’ll dispatch 14 more, one way or the other.

Postscript:

On 10Feb25 this essay was combined with four companion pieces and published as a pdf separate entitled, "Systematic review of the Pleurocera laqueata/troostiana complex."  That document is available for download as FWGNA Circular No. 8.

Notes:

[1] Goodrich, C. (1940) The Pleuroceridae of the Ohio River drainage system.  Occasional Papers of the Museum of Zoology, University of Michigan  417: 1-21.

[2] Plus a seventh set of “unknowns” and an eighth set he identified as “invasions” from the Alabama system.

[3] 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).

[4] For a brief biographical sketch of Isaac Lea, and a review of his contribution to our modern understanding of freshwater gastropod evolutionary biology, see:

• Isaac Lea Drives Me Nuts [5Nov19]

[5] Lea, Isaac (1841) Continuation of Mr. Lea's paper on New Fresh Water and Land Shells.  Proceedings of the American Philosophical Society 2: 11 – 15.

[6] Lea, Isaac (1843) Description of New Fresh Water and Land Shells.  Transactions of the American Philosophical Society (New Series)  8: 163 – 250.

[7] Lea, Isaac (1862) Description of a new genus (Goniobasis) of the Family Melanidae and eighty-two new species. Proceedings of the Academy of Natural Science of Philadelphia 19: 262 – 272.

[8] Lea, Isaac (1863) New Melanidae of the United States.  Journal of the Academy of Natural Sciences of Philadelphia (New Series) 5: 217 – 356.

[9] All 20 of these specimens are labeled “holotype” in the USNM collection.  Graf [10] considered most of them lectotypes, but I am not going to second-guess the USNM.

[10] Graf, D. L. (2001) The cleansing of the Augean stables.  Walkerana 12(27): 1 - 124.

[11] Rafinesque, C.S. (1831) Enumeration and account of some remarkable natural objects in the cabinet of Prof. Rafinesque, in Philadelphia.  Self-published, 4 pp.

[12] Dazo, B.C. (1965) The morphology and natural history of Pleurocera acuta and Goniobasis livescens (Gastropoda: Cerithiacea: Pleuroceridae). Malacologia 3:1-80.

[13] Dillon, R. T., Jr., S. J. Jacquemin & M. Pyron (2013) Cryptic phenotypic plasticity in populations of the freshwater prosobranch snail, Pleurocera canaliculata.  Hydrobiologia 709: 117-127.  [html] [pdf]  For more, see:

• Pleurocera acuta is Pleurocera canaliculata [3June13]
• Pleurocera canaliculata and the process of scientific discovery [18June13]

[14] Lea, I. (1831/34) Observations on the naiads, and descriptions of new species of that and other families.  Transactions of the American Philosophical Society (New Series) 4: 63 – 121.

[15] Scudder, N. P. (1885) Bibliographies of American naturalists – II. The published writings of Isaac Lea, LL.D.  Bulletin of the US National Museum 23: 1 – 278.

[16] Tryon, G. W. (1873) Land and Freshwater shells of North America Part IV, Strepomatidae.  Smithsonian Miscellaneous Collections 253: 1 - 435.

[17] Dillon, R. T., Jr. (2011) Robust shell phenotype is a local response to stream size in the genus Pleurocera (Rafinesque, 1818). Malacologia 53: 265-277. [pdf]  For a review, see:

• Goodbye Goniobasis, Farewell Elimia [23Mar11]

[18] Goodrich, C. (1930)  Goniobases of the vicinity of Muscle Shoals.  Occasional Papers of the Museum of Zoology, University of Michigan 209: 1 – 25.

[19] The TVA closed Wheeler Dam in 1936 and Pickwick Dam in 1938, creating a pair of reservoirs that covered the North Alabama shoals of the Tennessee River under 100 miles of slackwater and muck.  For my own personal lament, see the latter half of:

• The Union in Tennessee!  [15Aug23]

[20] Anthony, J.G. (1854) Descriptions of new fluviatile shells of the genus Melania Lam., from the western states of North America.  Annals of the Lyceum of Natural History of New York 6: 80 -132.

[21] Dillon, R.T., Jr. (2023b) The Freshwater Gastropods of North America Volume 6, Yankees at The Gap, and Other Essays.  FWGNA Project, Charleston, SC. [publications]

[22] Lea, Isaac (1868) New Unionidae, Melanidae, etc., chiefly of the United States.  Journal of the Academy of Natural Sciences of Philadelphia (New Series) 6: 303 – 343.

[23] Haldeman. S. S. (1841) A monograph of the Limniades and other freshwater univalve shells of North America. Volume 2.

[24] Reeve, L. A. (1860) Conchologia Iconica, or, Illustrations of the shells of molluscous animals. Volume 12, Plate 56.

[25] The INHS collection does hold four historic records of “Elimia” costifera from a creek in Hardin County, bordering the Ohio River about 250 miles south of Hennepin.  The University of Michigan also holds one historic lot of Goniobasis costifera (UMMZ 241604) from Hardin County.  That is simply too far away from Hennepin to have any bearing on this question.

[26] Lea, Isaac (1866) New Unionidae, Melanidae, etc. chiefly of the United States.  Journal of the Academy of Natural Sciences of Philadelphia (New Series) 6: 113 – 187.

[27] Lea, Isaac (1863) Descriptions of fourteen new species of Melanidae and one Paludina.  Proceedings of the Academy of Natural Sciences of Philadelphia 15:154 – 156.  Lea apparently read his paper in May of 1863, and “May” is printed on the bottom of the published pages, but the front of the published volume says, “June and July, 1863.”

[28] Conrad, T. A. (1834) New Fresh Water Shells of the United States, with coloured illustrations, and a monograph of the genus Anculotus of Say; also A synopsis of the American naiades.  Philadelphia, Judah Dobson.  76 pp, 8 plates.

[29] Say, T. (1829) Descriptions of some new terrestrial and fluviatile shells of North America.  New Harmony Disseminator of Useful Knowledge 2(18): 275 – 277.