> Habitat & Distribution

Lymnaea cockerelli was originally described as a subspecies of L. bulimoides (Lea 1841) from New Mexico, Colorado, Nebraska, and South Dakota.  Baker (1911) expanded its range across most of the American West from California throughout the entire Great Plains ecoregion, Texas to Montana.

Populations are typically found “in or near transient pools that frequently dry up during summer and fall” (Leonard 1959).  Baker passed along a report of a New Mexico population “from a water-hole that appeared to be dry most of the year” that survived package in cotton for 45 days (Pilsbry 1896).  We have confirmed Lymnaea cockerelli populations widely scattered across the entire western half of our four-state Great Plains study area, in roadside ditches, temporary pools, and farm ponds.

> Ecology & Life History

Little is known about the life history of L. cockerelli, beyond its well-documented ability to survive drought (Baker 1911, Leonard 1943, Leonard 1959).  A population of the closely related L. bulimoides inhabiting a vernal pool in Texas demonstrated continuous egg laying while open water persisted, averaging 2.8 ova daily with an 18.5 average per egg mass (Olsen 1941, 1944).  Lymnaea bulimoides may serve as intermediate hosts for the liver fluke, Fasciola hepatica (Shaw and Simms, 1929, Lang 1977), the parasite persisting through periods of estivation.

> Taxonomy & Systematics

Pilsbry and Ferris (1906) described Lymnaea bulimoides cockerelli as “readily separable” from typical L. bulimoides by the “more globose shape and shorter spire” of its shell.  Almost all subsequent authors have agreed, Baker (1911) describing it as “very characteristic and usually an easily separable variety of bulimoides.”

Hibbard and Taylor (1960) raised cockerelli to the full species level, pointing out that the shell morphological distinctions remained even where the ranges of cockerelli and bulimoides overlap.  Bequeart and Miller (1973) reported the discovery of sympatric populations of cockerelli and bulimoides (the techella form) in Arizona “without transitional specimens or other evidence of interbreeding,” confirming their reproductive isolation.  See may essay of 12Mar24 from the link below for a review of the long-running confusion between L. bulimoides and L. cockerelli.

Burch (1989) grouped cockerelli together with bulimoides, cubensis, and nine lesser known taxa into a subgenus Bakerilymnaea of the genus Fossaria, based on their bicuspid first marginal teeth.  Fossaria (Westerlund 1885) was subsequently adjudged junior to Galba (Schrank 1803) by the ICZN (1998).  We agree with Hubendick (1951), however, that the minimal morphological diversity demonstrated by the worldwide Lymnaeidae does not, in general, warrant subdivision of the family into genera.  Junior synonyms of L. cockerelli include sonomaensis (Hemphill 1906) and hendersoni (Baker 1909).  Lymnaea perpolita (Dall 1905) may be a senior synonym.

> Maps and Supplementary Resources

• Distribution of Lymnaea (Galba) in the Great Plains (2024)

> Essays

• See my post to the FWGNA blog of 28Dec06 for a review of The Classification of the Lymnaeidae.
• See my essay of 4June12 for a review of the large molecular phylogenetic literature that had accumulated on the Lymnaeidae as of that date, The Lymnaeidae 2012: Stagnalis yardstick. The (very sparse) data available at the time suggested a close association between L. bulimoides and L. cubensis, possibly synonymy of the former under the latter.  No data on L. cockerelli.  But see my essays of 13Feb24 and DATE below.
• I reviewed the entire worldwide fauna of crappy-little amphibious lymnaeids in 7June21, The American Galba and The French Connection.  Again, no data on L. cockerelli, alas.
• In my post of 6July21 I reviewed the results of the big international research effort of Alda and colleagues (2021), Exactly 3ish American Galba.  No more data available for L. cockerelli in 2021 than there were in 2012, but again, see my essays of 13Feb and DATE below.
• In my essay of 13Feb24 I finally addressed the rhetorical question, What is Lymnaea bulimoides?  We review the history of the taxon as it has been applied to living populations of lymnaeid snails throughout the American West, especially focusing on longstanding confusion with L. cubensis/viator.  This essay is essential background for my follow up of 12Mar24, addressing the confusion between L. bulimoides and L. cockerelli. 
• On 12Mar24 I reviewed the evidence confirming Lymnaea (Galba) cockerelli, Number 15 in the FWGNA list of distinct biological species of North American lymnaeid snails.  That essay includes lots of additional figures comparing the shell morphology of L. cockerelli to L. bulimoides, and a summary table translating Burch's (1989) five-species, six-subspecies model of the subgenus Bakerilymnaea to the clean, three-species FWGNA model.

> References

Baker, F. C. (1911) The Lymnaeidae of North and Middle America, Recent and Fossil.  Special Publication, vol. 3. Chicago Academy of Natural Sciences, Chicago.   
Baker, F. C. (1928) Freshwater Mollusca of Wisconsin, Part I, Gastropoda. Bull. Wisc. Geol. Natur. Hist. Survey, vol. 70. University of Wisconsin Press, Madison.
Bequaert, J.C. and Miller, W.B. 1973. The Mollusks of the Arid Southwest with an Arizona Check list. University of Arizona Press, Tucson, Arizona. 271 pp.
Burch, J.B. 1989. North American Freshwater Snails.  Malacological Publications, Hamburg, MI.  365 pp. 
Clarke, A.H. 1981. The Freshwater Molluscs of Canada.  National Museum of Natural Sciences, National Museums of Canada, Ottawa, Canada. 
Dillon, R.T., Jr. 2000.  The Ecology of Freshwater Molluscs.  Cambridge University Press, Cambridge, United Kingdom.
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.
Haldeman, S.S. 1867. Description of a new species of Limnea. American Journal of Conchology. 3: 194.
Hibbard, C. W., and D. W. Taylor. 1960. Two late Pleistocene faunas from southwestern Kansas. Contributions from the Museum of Paleontology 16: 1-223.
Hubendick, B. 1951.  Recent Lymnaeidae. Their variation, morphology, taxonomy, nomenclature, and distribution. Kungl. Svenska Vetensk. Akad. Handl., 3, 1-223. 
Lang, B.Z. (1977) Snail and mammalian hosts for Fasciola hepatica in eastern Washington.  Journal of Parasitology 63: 938 – 939.
Lea, I. 1841. On fresh water and land shells (continuation) [fifty-seven new species]. Proceedings of the American Philosophical Society. 2(17): 30-35 [7 May 1841]
Olsen, O.W. 1941. The biology and ecology of the snail, Stagnicola bulimoides techella (Hald), intermediate host of Fasciola hepatica Linn., in South Texas. Journal of Parasitology Suppl, 276: 18.
Olsen, O.W. 1944. Bionomics of the lymnaeid snail, Stagnicola bulimoides techella, the intermediate host of the liver fluke in southern Texas. Journal of Agricultural Research (Washington, D.C.) 69(10): 389-403.
Pilsbry, H.A. 1891. Land and Fresh-water mollusks collected in Yucatan and Mexico.  Proceedings of the Academy of Natural Sciences of Philadelphia 43: 310 – 334.
Pilsbry, H.A. (1896)  Limnaea bulimoides Lea resisting drought.  The Nautilus10:96.
Pilsbry, H.A.and Ferriss, J.H. 1906. Mollusca of the southwestern states. II. Proceedings of the Academy of Natural Sciences of Philadelphia 58: 123-175.
Shaw, J.N. and Simms, B.T. 1929. Galba bulimoides Lea an intermediate host of Fasciola hepatica in Oregon.