George Morgan Davis (1938 – 2024): The Director’s Cut

Dillon, R.T., Jr., G. Rosenberg & P.M. Mikkelsen (2025) George Morgan Davis (1938 - 2024): Life, work, and legacy.  Malacologia 68: 3 - 26. [pdf]

The email was delivered to my inbox in the mid-afternoon Thursday, June 20, 2024, and I don’t remember being terribly surprised by the news.  Dr. George M. Davis, my major advisor at Penn 1977 – 1982 was dead.  His wife, my old friend Elaine Hoagland, was asking me to pass the word along to the wider malacological community.

King George was the last monarch of American Malacology, guiding our discipline from the classical typology of the 19th century to the neoclassical typology of the present day.  I posted single-paragraph tributes on Facebook and the Mollusca list server early that next morning, and was gratified to see how rapidly the word spread.

George M. Davis (1938 - 2024)

Gary Rosenberg, George’s successor at the Academy of Natural Sciences in Philadelphia, stepped forward to offer a memorial at the annual meeting of the American Malacological Society, upcoming just six weeks away in Pasadena, and President Pat Krug found room on the program.  Gary also began to compile a bibliography of George’s published works at that time.

Elaine also mentioned to me, in the days immediately following her husband’s death, that she had separately contacted our colleague Chuck Lydeard, George’s immediate successor as Editor-In-Chief of Malacologia, about a special volume of to be published in his memory as well.  I suppose I had assumed that Gary would take the lead on George’s professional obituary for that volume, just as he had taken the lead for the oral tribute at the AMS. 

So, the email from Chuck that arrived in my inbox 15Aug25 surprised me quite a lot.  Chuck confirmed that an entire issue of Malacologia, dedicated to the memory of my influential mentor, was indeed nearing completion.  Paula Mikkelsen and Alan Kabat had joined Gary Rosenberg to compile an extensive GMD bibliography, now grown to 200 titles, together with lists of all the species and higher taxa he had described, all the species named for him, and all the articles written about him, for publication as the lead article in that memorial issue.  But none of our distinguished colleagues apparently felt called to write a biography of the man to explain all the fuss. Nor could anybody else alive on God’s green earth be found to volunteer.

 

And so at this late date, 14 months into a 15-month project, with every other option exhausted and time running out, pushed beyond the point of despair, Chuck Lydeard was contacting me to ask if I would take the lead authorship of the lead article in a George M. Davis memorial issue of Malacologia.  My coauthors Rosenberg and Mikkleson would contribute the bibliography half, and I the biography half.  My deadline would be the end of September, six weeks away.

 

And I felt duty-bound to accept.  I didn’t like George Davis.  I don’t know anybody who did.  And although I did work closely with him during that brief window 1977 – 1982, and got to know him better than I cared to during those five years, after I left Philadelphia we really did not keep in touch.  Our areas of research interest just barely intersected, and our philosophies of science not at all.

 

But George Davis helped me.  He administered the best facilities for malacological research in the world at that time, and he made the superb ANSP collections, the wonderful library, the modern laboratory, and rooms full of equipment and cabinets bulging with supplies all available to me, free and without obligation, and otherwise left me alone, and that is exactly what I needed.

 

So, I went to work on a tribute for my major advisor.   And I confess I did not quite make my deadline, but by the first week of October had a first draft ready to share with my coauthors.  Divided into six sections, that first draft reviewed George’s 60-year career, contextualized his manifold scientific contributions, and transmitted some feeling for the outsized influence he wielded in American Malacology during the latter half of the 20th Century, an influence that continues to the present day.  And in an effort to humanize the man, each of those six sections was introduced with a story, told in the first person, in which I reminisced about my own personal experiences with my major advisor in the late 1970s.

 

And I added a top layer as well.  Looking back on 20th Century Malacology from a 25-year perspective, I found myself able to trace the evolution of our entire discipline in the career of Dr. George M. Davis.  Working on his dissertation at the University of Michigan Museum of Zoology 1960 - 1965, Davis was born into classical, 19th-century typology.  But the Modern Synthesis of Darwin + Mendel was ascending, hypothesis-driven, grounded in the theory of Fisher, Haldane, and Wright, rigorously scientific.  And just dawning at that very moment was a new age of molecules and computer analysis, ultimately to devolve into a 21st-century neoclassicism just as typological as the 19th.

 

Davis did, in fact, include a set of rigorously-designed breeding experiments in his dissertation research, published in 1967, as well as classical morphological studies and remarkably forward-looking protein electrophoretic analysis.  Yet even though his breeding studies answered the question his dissertation addressed, and neither the morphology nor the molecules contributed, Davis never tested another hypothesis throughout the remainder of his 60-year career.  Quoting myself directly: 

“George Davis had been baptized Presbyterian-form in modernity with his early laboratory experiments on hybridization, sprinkled not dunked.  Then finding objective, hypothesis-driven science too constraining, he jumped over the deeper waters of Fisher, Mayr, Dobzhansky and Simpson to the Neoclassical now, drawing our discipline along with him.”

 Well, such vivid language is never going to find publication in a scientific journal, and well I knew it, even as the Christian denominations were flying off my fingertips.  That first draft of early October was edited significantly by my coauthors, as is their right.  Paula, in particular, objected to my use of the first person in the reminiscences, which I certainly understand.  But conversion to the third person and the passive voice, much color is sacrificed.  And awkwardness left in the wake.

 

And Paula, Gary, and I kept Chuck Lydeard on the cc line as we passed the drafts around.  Rather early in the process Chuck alluded to sending our manuscript out for peer review, which seemed a wry comment on the vitality of our discipline.  “I’m not saying our science is dead, but in Malacology, obituaries are peer-reviewed.”  I needn’t have worried about that step, however, as Alan Kabat ultimately contributed a couple excellent insights which I was pleased to incorporate.

 

So, the George M. Davis Memorial issue of Malacologia was published in December, and the lead article by Dillon, Rosenberg and Mikkelsen is downloadable from this [pdf] link.  Although the paper as ultimately published does convey the overall flavor of the Scotch pie I baked in September, much of the spice has been lost.

 

Then for those of my readership who prefer their monthly dose of Rob Dillon redolent of creekbank, ancient tome, and spoiled ethanol, this month I have made FWGNA Circular #9 available for download from the website, here:

 

George Morgan Davis (1938-2024): The Director’s Cut

 

This version is very nearly that first early-October 2025 draft of my manuscript, unexpurgated, with a sprinkling of subsequent improvements.  It is missing the section on George Davis’ personal life, which was subsequently added by Gary Rosenberg, as well as the complete GMD bibliography and supporting sections as contributed by Gary and Paula working together. It does conclude with a literature-cited section, to the references cited in text only.  Also included are several nice figures not appearing in the published journal article, and a couple really good stories.  Bon appetite.

The birth, death, and resurrection of Melania acutocarinata

It was from the pen of our old buddy Isaac Lea [5Nov19], early on a frosty morning in 1841, that Melania acuto-carinata was born, in brief Latinate form, number 46 in a litter of 57 pleurocerid puppies [1].  Among its more famous siblings were #2 castanea [12Nov24], #7 ebenum [3Oct19], #10 clavaeformis [20Feb07, 12Oct09], #25 virgata [9May23], and #37 edgariana [5June20].  Lea followed with more complete English descriptions and figures of the entire litter in 1843 [2].

The type locality of Melania acuto-carinata was vague, “Tenn., Dr Currey.”  We first met Dr. Richard Owen Currey (1816 – 1865), impeccably credentialed with Presbyterian heritage and doctorate from the University of Pennsylvania, back in [3Oct19].  Currey was born and raised in Nashville but moved to Knoxville in 1846 to become “the first person with an earned doctorate to teach science” at East Tennessee University, later the University of Tennessee [3].

Melania acuto-carinata [2]

Lea’s description of the acuto-carinata shell was almost as vague as its type locality: “It seems to be distinct in its large carina which extends over all the whorls, but it is scarcely distinct on the last.”  Nevertheless, the nomen was launched into malacological stardom in 1858 by the English naturalists Henry and Arthur Adams, in their justifiably maligned “Genera of Recent Mollusca” [4].

It seems highly unlikely to me that either of the Adams brothers ever laid eyes on a North American pleurocerid snail in their entire, justifiably-maligned lives.  Tryon [5] reprinted their classification verbatim in 1873, “in order that the insufficiency of their genera may become more apparent from the incongruous assemblage of shells of which they have composed them.” 

 

Among the 16 genera Henry and Arthur recognized in the Melanidae was Io (of Lea) “remarkable for the peculiar elongation of the axis anteriorly, and for the spinose nature of the last whorl.”  Fine.  Then, as a subgenus of Io (good grief!) the Adams brothers proposed, “Elimia” for pleurocerids bearing shells fusiformly ovate, “whorls reticulate or nodulose, carinate in the middle.”  And under Elimia they listed 16 apparently random pleurocerid specific nomina in alphabetical order, the first of which was “acuticarinata, Lea,” without the dash, misspelled, bearing a shell that is neither reticulate nor nodulose.

 

Tryon dismissed the Adams classification from further consideration and assigned acutocarinata to the genus Goniobasis, newly proposed by his mentor Isaac Lea in 1862 [6].  And pretty much the entire malacological community fell in line with Tryon and Lea, most notably Calvin Goodrich [23Jan07], toward whom our attention now turns.

 

In a 1939 paper that should be better known than it is, Goodrich [7] used Goniobasis acutocarinata as an example of “depauperization,” by which he meant “the outward manifestation of disease, accident or malnutrition or a reaction to inimical environment.”  He wrote: 

“In Goniobasis, very loose coiling appears to be a sign of depauperization.  Goniobasis acutocarinata, although described as a species, has not been found in pure colonies. Lea, its author, had only one specimen.  The shell occurs as a rare variant among G. clavaeformis in springs and spring branches of East Tennessee.” 

For that reason, in his influential review of 1940, Goodrich [8] synonymized Melania acutocarinata Lea 1841 under Goniobasis clavaeformis (Lea 1841).  And that should have been the end of it.  Pleurocerid nomina that did not survive Calvin Goodrich’s 1930 – 1950 piecemeal crusade to monograph the family were not, as a rule, listed or figured in the Burch Bible [9].  They have died, been buried, and forgotten, RIP.

 

P. clavaeformis from Burch [9]

And that is indeed what happened to 12 of the 13 specific nomina [10] synonymized under clavaeformis by Goodrich in 1940.  They disappeared, never to be seen again.  But not acutocarinata.

Although generally following Goodrich quite closely, in the 1980s Jack Burch [9] gave Goodrich’s system one great big kick and a bunch of little tiny anonymous tweaks [11].  Out of a sense obligation to the letter of the ICZN law [12], Burch elected to resurrect the Adams brothers’ obscure Elimia in place of the widely used Goniobasis, confounding the work of Lea, Tryon, Goodrich and everybody else over the previous hundred years.  Following Henry Pilsbry [26Jan21] and Pilsbry’s local collaborator Samuel Rhoads [13, 14], Burch selected acutocarinata as the type of the Adams polyglot genus, by virtue of its first place in the alphabetized list of 16 odd lot species included.

 

And among his tweaks, Burch saved Isaac Lea’s acutocarinata.  To be precise, what he did was exhume two acutocarinata specimens from the UMMZ collection (Figs 404 and 405 above) and figure them alongside a singleton specimen of typical clavaeformis (Fig 403), labeling both of the former “E. acutocarinata = ? E. clavaeformis.”  Why did Burch dump 12 of Goodrich’s clavaeformis synonyms and double-figure the thirteenth?  I don’t know.  If it was a coincidence that acutocarinata was the type of his resurrected Elimia, it was certainly a convenient one.  But for whatever reason, Isaac Lea’s 1841 acutocarinata was spared into a kind of taxonomic purgatory, a place of shadows, neither alive nor dead.

 

In retrospect, I myself should have rescued the nomen from the netherworld for use at the subspecies level in my 2011 paper on Goodrichian Taxon Shift [15], later renamed cryptic phenotypic plasticity (CPP) [16].  Longtime readers will remember that I selected three sites in East Tennessee (and one in North Georgia) inhabited upstream by what I was calling, at that time, Goniobasis acutocarinata, in the mid-reaches by what I was calling, at that time, Goniobasis clavaeformis, and downstream by what I was calling, at that time, Pleurocera unciale.  Those sites included the famous [17] Indian Creek tributary of the Powell on the VA/TN border (IC, map way down below) and the even more famous [19] Pistol Creek of Maryville (PC), as well as the (rather obscure) Lick Creek tributary (LC) of the Hiwassee.

 

My allozyme analysis showed that each acutocarinata population was more genetically similar to its downstream clavaeformis population than to any other acutocarinata, and that each unciale population was genetically more similar to its upstream clavaeformis population than to any other unciale.  On that basis I folded both acutocarinata (no surprise) and unciale (big surprise) under clavaeformis, and both Goniobasis and Elimia under Pleurocera.

 

P. clavaeformis in Indian Creek, Va - Tn

I elected, however, to save uncialis/unciale at the subspecific level, as Pleurocera clavaeformis unciale (Hald 1841), both because of its utility to describe a familiar shell form, and its indexing function to the older scientific literature.  Note that subspecific designation does not carry with it any assumption regarding the heritability of the distinguishing characteristics, much less genetic relationships [20].  It’s just useful.

By the same reasoning, I should also have elevated acutocarinata back up from taxonomic purgatory to the subspecific level, as Pleurocera clavaeformis acutocarinata (Lea 1841).  That should have happened back in 2011.  In my own defense, all I can offer is that unciale was recognized at the species level by Goodrich in 1940, and acutocarinata was not, and resurrecting old pleurocerid names from the nether regions is not the direction anybody wants to go.  But I’ve done it subsequently [21].  The indexing utility of Lea’s nomen acutocarinata is just as significant as that of Haldeman’s unciale/uncialis, probably greater, and the shell morphology just as distinctive.

 

Then let it be so, better late than never.  This month I have added a new Pleurocera clavaeformis acutocarinata page to the FWGNA website, and a new photo to the FWGTN gallery, and a new entry in the FWGTN dichotomous key – the second time I have found myself doing this in recent memory [22].  The number of freshwater gastropod species and subspecies now covered by the FWGNA web resource is 145 + 1 = 146. 

 

And I have dug back through my old collections and re-identified 22 populations of P. clavaeformis from the typical subspecies to acutocarinata.  Almost all of these inhabit small streams south of Knoxville, primarily direct tributaries of the main river or of the Hiwassee.  The Indian Creek population, way up on the Virginia/Tennessee Line, appears to be an outlier.

 

In all my earlier writings on Goodrichian Taxon Shift and CPP, I have tended to favor explanations that are not heritably genetic.  Although I have always left room for natural selection, most of the column inches in the discussion sections of the papers I have published on this subject [23] focus on the (many and striking) laboratory demonstrations of ecophenotypic plasticity in freshwater gastropod shell morphology.

 

Reidentified acutocarinata in blue

Quite recently a third possible explanation has dawned on me, in the specific case of the apparent transition between P. clavaeformis populations bearing shells of the typical morphology, and those bearing shells of the acutocarinata morphology.  Hybridization [24].

Populations of P. clavaeformis reach maximum abundance in streams of moderate size – marginally wadeable, where you’d bait up for redeye bass and bream.  Populations certainly extend upstream into colder waters suitable for trout, however, where in East Tennessee they bump into big populations of P. troostiana [25].

 

It is conceivable to me that Pleurocera clavaeformis acutocarinata may be a clavaeformis x troostiana hybrid.  I don’t have any genetic evidence of that [26].  This is just a speculation, based on the acutocarinata shell, which appears morphologically intermediate between the two species, both in its carination and in its overall length-to-width, body-whorl-to-apex slenderness.

 

But to conclude, I must emphasize.  Whether the shell morphological distinction between the (now three) subspecies of P. clavaeformis results from adaptation, hybridization, or ecophenotypic plasticity is irrelevant to their subspecific identity.  Here we resurrect Lea’s 1841 nomen acutocarinata because it is a useful descriptor of shell form, and because it has appeared frequently in the published literature.  And will appear again.  Stay tuned.

Notes:

[1] 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.

 

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

 

[3] Quoting the Richard Owen Currey entry in the University of Tennessee “Volopedia” archives: “In 1861, Currey entered Confederate service as a chaplain-surgeon. In 1865, he started caring for Union prisoners in North Carolina. He died while working in a disease-infested hospital on February 17, 1865.” He must have been a wonderful man.  It would have been an honor to shake his hand.

 

[4] Adams, Henry and Arthur (1854 - 1858) The Genera of Recent Mollusca Arranged According to Their Organization. In Three Volumes.  London: J. Van Voorst.  The Melanidae is covered in Volume 1, pp 293 – 311.

 

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

 

[6] 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.

 

[7] Goodrich, Calvin (1939) Aspects of depauperization.  The Nautilus 52: 124 – 128.

 

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

 

[9] 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).

 

[10] Which I will not list, not even in the footnote of an obscure blog post.

 

[11] For the record, here is the complete text of Burch’s Supplemental Note #23: “Elimia H. and A. Adams (type species Melania acutocarinata Lea 1841 = Melania clavaeformis Lea 1841) is used in place of its better-known synonym Goniobasis Lea 1862 (type species Goniobasis osculata Lea 1862).  The classification of the genus Elimia presented here, and the distribution of the various recognized species and subspecies, is that of Goodrich (1930a, 1936, 1939d, e, 1940d, 1941a, b, c, 1942b, 1944d, 1945, 1950).  No attempt has been made to assess the taxonomic validity of the species and subspecies.”

 

[12] Burch, J. B. 2001. On the genus name Goniobasis (Elimia - Gastropoda: Pleuroceridae) and other recent nomenclatural inconsistencies. Walkerana 12:97-105.

 

[13] Pilsbry, H. and S. Rhoads. 1896. Contributions to the Zoology of Tennessee, Number 4, Mollusca. Proc. Acad. Nat. Sci. Phila. 1896:487-506.

 

[14] Note, however, that Pilsbry never used “Elimia” himself.  His imperial majesty continued to prefer Goniobasis in every paper he ever wrote or edited for The Nautilus.  And all the labels in the ANSP collection read “Goniobasis” to this day.  For example:

• Pilsbry, H. 1916. Goniobasis in western Pennsylvania. Nautilus 30:4-5.

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

 

[16] For an entry into the rather extensive literature of CPP in North American pleurocerid snails, see:

• Goodrichian taxon shift [20Feb07]
• Mobile Basin III: Pleurocera puzzles [12Oct09]
• Pleurocera acuta is Pleurocera canaliculata [3June13]
• Pleurocera canaliculata and the process of scientific discovery [18June13]
• Elimia livescens and Lithasia obovata are Pleurocera semicarinata [11July14]

[17] I was wading in waters of Indian Creek, just like John, when the scales fell from my eyes.  John Robinson and I published a gray-literature report on those findings to the VDGIF in 2007 [18], and I coined the term “Goodrichian Taxon Shift” on this blog.  See:

• Goodrichian Taxon Shift [20Feb07]

[18] Dillon, R. T. & J. D. Robinson (2007b) The Goniobasis ("Elimia") of southwest Virginia, II. Shell morphological variation in Goniobasis clavaeformis. Report to the Virginia Division of Game and Inland Fisheries, contract 2006-9308. 12 pp. [pdf]

 

[19] It was at Pistol Creek that I ultimately discovered a forgotten pleurocerid species cryptic under P. simplex.  See:

• The cryptic Pleurocera of Maryville [13Sept16]
• The fat simplex of Maryville matches type [14Oct16]
• One Goodrich missed: The skinny simplex of Maryville is Pleurocera gabbiana [14Nov16]

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

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

[21] I resurrected Isaac Lea’s (1862) lyonii, previously subsumed by Goodrich (1940) under laqueata, as a subspecies of P. troostiana in:

• The return of Captain Lyon [6July20]

[22]  I added a new Pleurocera laqueata castanea page to the FWGNA website last fall, with corresponding entries in the FWGTN species gallery and dichotomous key.  See:

• Reticulate evolution in the North American Pleuroceridae [12Nov24]

[23] Published papers on CPP:

• Dillon, R. T. (2011) Robust shell phenotype is a local response to stream size in the genus Pleurocera (Rafinesque 1818). Malacologia 53: 265-277. [pdf]
• 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]
• Dillon, R. T. (2014) Cryptic phenotypic plasticity in populations of the North American freshwater gastropod, Pleurocera semicarinata.  Zoological Studies 53:31. [pdf]

[24] For more on hybridization in pleurocerids, see:

• Widespread hybridization between Pleurocera laqueata and P. troostiana in streams of the Tennessee/Cumberland [15Oct24]
• Reticulate evolution in the North American Pleuroceridae [12Nov24]

[25] And simplex. And gabbiana.  But I don’t think that is relevant to my argument here.

 

[26] Just the opposite, actually.  In our VDGIF allozyme study [27], John Robinson and I did run gels on N = 31 G. clavaeformis (C1) and N = 30 G. “arachnoidea” (A1 = troostiana) from Indian Creek, finding a little bit of evidence of mixing at some loci, but fixed differences at three others.

 

[27] Dillon, R. T. & J. D. Robinson (2007a) The Goniobasis ("Elimia") of southwest Virginia, I. Population genetic survey. Report to the Virginia Division of Game and Inland Fisheries, contract 2006-9308. 25 pp. [pdf]

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 14: 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.