Coordinator, FWGNA Project
P.O. Box 31532
Charleston, SC 29417
Voice (843) 670-8002
Ph.D. 1982, University of Pennsylvania, Philadelphia. Dissertation: The correlates of divergence in isolated populations of the freshwater snail, Goniobasis proxima. 182 pp. Dissertation Abstracts 43: 615B
B.S. 1977, Virginia Tech, Blacksburg. Biology, in honors, with distinction. Honors Thesis: Factors in the distributional ecology of upper New River mollusks (Va/NC)
III. Professional Experience
1991 - 2016. Associate Professor, Department of Biology, College of Charleston, Charleston, SC. Teaching Evolution 350, Genetics Lecture 212/311, Genetics Lab 305L, Introduction to Cell and Molecular Biology 111, Evolution Ecology and Biology of Organisms 112, Honors Biology lecture and lab, Undergraduate Research (38 projects).
1986 - 2016. Graduate Faculty in Marine Biology, College of Charleston. (12 M.S. students, including 6 as major advisor).
1983 - 1991. Assistant Professor, Department of Biology, College of Charleston.
1982 - 1983. Assistant Professor, Department of Biological Sciences, Rutgers University, New Brunswick, NJ. Sabbatical replacement, teaching General Biology, Genetics, Invertebrate Zoology.
1981 - 1982. AAAS Fellow, Oceans & Environment Program, Office of Technology Assessment, U.S. Congress. Assigned to Clean Water Act, Section 404. For further information, see Science 214: 52 - 53.
1980 - 1981. Teaching Assistant, University of Pennsylvania, Philadelphia. Limnology, with Dr. Ruth Patrick.
1977. Field & Lab Technician, Center for Environmental Studies, Virginia Tech, Blacksburg. Ecosystems data collection.
1975. Biological Aide, Department of
& Wildlife Development, Tennessee Valley Authority, Norris, TN.
Freshwater Mussel Survey.
Invasive Species Expert Tier 2.
2006. Leader, Pacific Northwest Taxonomic Workshop - Gastropoda.
The Xerces Society, Missoula, MT.
2005 - 2010. Snake River Physa Technical Team. US Bureau of Reclamation, Boise, Idaho.
2005. Springsnail Science Panel. US Fish & Wildlife Service, Boise, Idaho.
2000. Piedmont Ecoregion / South Atlantic Basin Aquatic Experts Workshop.
The Nature Conservancy, Seabrook Island, SC.
1998 - present. Coordinator, Freshwater Gastropods of North America project.
1998 - 2003. Chair, Committee on Status & Distribution of Gastropods,
Freshwater Mollusk Conservation Society
1993 - 1997. WRCC-99 working group on Broodstock Management,
Genetics and Breeding Programs for Molluscan Shellfish.
1991. Atlantic Slope Freshwater Mollusk Conservation Workshop.
The Nature Conservancy, Arlington, Va.
1985 - 2012.
2005 - 2009, 2011-15. Treasurer, Lowcountry Phi Beta Kappa Association.
2012. Representative to the 43rd Trienniel Council, Palm Beach.
2003 - 2005, 2009 - 10. Secretary, Lowcountry Phi Beta Kappa Association.
2007 - present. Councilor, Charleston Chapter of Sigma Xi.
2011. Certificate of Recognition, Charleston Chapter of Sigma Xi.
1994 - 2001, 2003 - 07. Secretary-Treasurer.
2001 - 2002. President-elect & Program Chair.
2002 - 2003. Chapter President.
1998 - present. Listowner/moderator of Chs-Sci-Net, a Sigma Xi listserv dedicated to
science in the South Carolina lowcountry. Part of the
AIBS Evolution Listserv Project. See Evolution 54:1834-1835.
2002 - 2013. Chair, Constitution /Bylaws Committee, American Malacological Society
(formerly, American Malacological Union.)
2002 - 2009. Chair, Resolutions Committee.
2002-2005, 2007 - 10. Councilor, American Malacological Society.
1999 - 2002. Vice President, Pres-Elect, and President. American Malacological Society.
Host of 68th annual meeting in Charleston, August 2002.
2015 - 2018. Advisory Council, Christian-Jewish Council of Greater Charleston (now The
Charleston Interreligious Council.
2001 - 2016.
Coordinator of Darwin
311: 769 - 771. (10Feb06).
Gastropods Report, Great Smoky Mountains National Park.
2017. Dillon, R. T. The freshwater gastropods of The Ohio: An interim report. Society for Freshwater Science, Raleigh, NC.
R. T. The distribution of commonness and rarity
in the freshwater gastropod fauna of U.S.
Atlantic drainages. American Malacological Society,
University of Michigan Biological Station, Douglas Lake, MI.
2013. Dillon, R. T., S. Jacquemin and M. Pyron. Phenotypic plasticity in the freshwater gastropod genus Pleurocera: Extreme, cryptic, or both? Society for Freshwater Science (Formerly NABS), Jacksonville, FL.
2011. Dillon, R. T., A. R. Wethington and C. Lydeard. The evolution of reproductive isolation in a simultaneous hermaphrodite, the freshwater snail Physa. American Malacological Society, Pittsburgh, PA.
2011. Dillon, R. T.
Robust shell phenotype is a local response to stream size in the genus Pleurocera.
Freshwater Mollusk Conservation Society, Louisville, KY.
Dillon, R.T., Jr., M.J. Ashton, W.K. Reeves, T.P. Smith, T.W. Stewart, & B.T. Watson (2019a) Atlantic drainages, Georgia through Pennsylvania. Freshwater Gastropods of North America, Volume 1. FWGNA Press. 199 pp.
Dillon, R.T., Jr. (2019b) Essays on The Pulmonates. Freshwater Gastropods of North America, Volume 2. FWGNA Press. 215 pp.
Dillon, R.T., Jr. (2019c) Essays on The Prosobranchs. Freshwater Gastropods of North America, Volume 3. FWGNA Press. 256 pp.
Dillon, R.T., Jr. (2019d) Essays on Ecology and Biogeography. Freshwater Gastropods of North America, Volume 4. FWGNA Press. 257 pp.
Dillon, R.T. (2000) The Ecology of Freshwater Molluscs. Cambridge University Press. 509 + xii pages, 27 tables, 99 figures. ISBN: 0 521 35210 X. Table of contents, sample chapter, and reviews are available from the web site.
Gooding, E. L., A. E. Fowler, D. Knott, R. T. Dillon, T. Brown, M. R. Kendrick, & P. R. Kingsley-Smith (2018) Life history and phenological characteristics of the invasive island apple snail, Pomacea maculata (Perry, 1810) in stormwater retention ponds in coastal South Carolina, USA. Journal of Shellfish Research 37: 229 - 238. [PDF]
Alda, P., M. Lounnas, A. Vázquez, R. Ayaqui, M. Calvopiña, M. Celi-Erazo, R. T. Dillon, P. Jarne, E. Loker, F. Pareja, J. Muzzio-Aroca, A. Nárvaez, O. Noya, L. Robles, R. Rodríguez-Hidalgo, N. Uribe, P. David, J-P. Pointier, & S. Hurtrez-Boussès (2018). A new multiplex PCR assay to distinguish among three cryptic Galba species, intermediate hosts of Fasciola hepatica. Veterinary Parasitology 251: 101-105. [html] [PDF]
Dillon, R. T. (2014) Cryptic phenotypic plasticity in populations of the North American freshwater gastropod, Pleurocera semicarinata. Zoological Studies 53:31. [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]
Wethington, A.R., D. L. Kirkland and R. T. Dillon (2012) Sex bias in interspecific copulation between the hermaphroditic freshwater snails, Physa acuta and Physa pomilia (Physidae). American Malacological Bulletin 30: 281-285. [PDF]
R. B., S. A. Orlofske, V. E. Melin, R.
T. Dillon, and P. T. J. Johnson (2011)
Land use and wetland spatial position jointly determine
amphibian parasite communities. EcoHealth 8:
Dillon, R. T., A. R. Wethington, and C. Lydeard (2011) The evolution of reproductive isolation in a simultaneous hermaphrodite, the freshwater snail Physa. BMC Evolutionary Biology 11:144. [html] [PDF]
Dillon, R. T. and J. D. Robinson (2011) The opposite of speciation: Population genetics of Pleurocera (Gastropoda: Pleuroceridae) in central Georgia. American Malacological Bulletin 29: 159-168. [PDF]
Solomon, C. T., J. D. Olden, P. T. J. Johnson, R. T. Dillon, and M. J. Vander Zanden (2010) Distribution and community-level effects of the Chinese mystery snail (Bellamya chinensis) in northern Wisconsin lakes. Biological Invasions 12: 1591-1605. [PDF]
Dillon, R. T. (2009) Empirical estimates of reproductive isolation among the Physa species of South Carolina (Pulmonata: Basommatophora). The Nautilus 123: 276-281. [PDF]
Wethington, A.R., J. Wise, and R. T. Dillon (2009) Genetic and morphological characterization of the Physidae of South Carolina (Pulmonata: Basommatophora), with description of a new species. The Nautilus 123: 282-292. [PDF]
Cowie, R. H., R.
T. Dillon, D. G. Robinson and J. W. Smith (2009) Alien
non-marine snails and slugs
of priority quarantine
importance in the United States: A preliminary risk assessment.
Malacological Bulletin. 27: 113-132.
Dillon, R. T. and J. J. Herman (2009) Genetics, shell morphology, and life history of the freshwater pulmonate limpets Ferrissia rivularis and Ferrissia fragilis. Journal of Freshwater Ecology 24: 261-271. [PDF]
Dillon, R T. and J. D. Robinson (2009) The snails the dinosaurs saw: Are the pleurocerid populations of the Older Appalachians a relict of the Paleozoic Era? Journal of the North American Benthological Society 28: 1 - 11. (Rosemary Mackay Award) [PDF]
Reeves, W. K., R. T. Dillon and G. A. Dasch (2008) Freshwater snails (Mollusca: Gastropoda) from the Commonwealth of Dominica with a discussion of their roles in the transmission of parasites. American Malacological Bulletin 24: 59 - 63. [PDF]
J. D. and
R. T. Dillon (2008)
Genetic divergence among sympatric populations of three
of oyster drills (Urosalpinx)
in Cedar Key, Florida. Bulletin
of Marine Science
Dillon, R. T., J. D. Robinson, and A. R. Wethington (2007) Empirical estimates of reproductive isolation among the freshwater pulmonates Physa acuta, P. pomilia, and P. hendersoni. Malacologia 49: 283 - 292. [PDF]
Dillon, R. T., and A. R. Wethington. (2006) No-choice mating experiments among six nominal taxa of the subgenus Physella (Basommatophora: Physidae). Heldia 6: 41 - 50. [PDF]
and A. R.
The Michigan Physidae revisited: A population genetic study. Malacologia 48: 133
- 142. [PDF]
Dillon, R. T.,
Robinson, T. P. Smith, and A. R. Wethington.
isolation between freshwater pulmonate snails Physa virgata
and P. acuta.
Naturalist 50: 415
- 422. [PDF]
R. T., T. E. McCullough, and C. E. Earnhardt.
Estimates of natural allosperm storage capacity and
self-fertilization rate in the hermaphroditic freshwater pulmonate
Invertebrate Reproduction and
Development 47: 111-115. [PDF]
J., M. G. Harasewych, and R. T. Dillon.
Population divergence in the sinistral Busycon
whelks of North
with special reference to the east Florida ecotone. Marine
Biology 145:1167-1179. [PDF]
T., and R. C. Frankis.
High levels of DNA sequence divergence in isolated populations of the
freshwater snail, Goniobasis. American
Bulletin 19: 69 - 77. [PDF]
Dillon, R. T., C. E. Earnhardt, and T. P. Smith. (2004) Reproductive isolation between Physa acuta and Physa gyrina in joint culture. American Malacological Bulletin 19: 63 - 68. [PDF]
T. M., and R. T. Dillon.
Species composition and geographic distribution of Virginia's
freshwater gastropod fauna: A
review using historical records.
Malacological Bulletin 19: 79 - 91. [PDF]
Dillon, R. T., A. R. Wethington, J. M. Rhett and T. P. Smith. (2002) Populations of the European freshwater pulmonate Physa acuta are not reproductively isolated from American Physa heterostropha or Physa integra. Invertebrate Biology 121: 226-234. [PDF]
Dillon, R. T. and A. J. Reed (2002) A survey of genetic variation at allozyme loci among Goniobasis populations inhabiting Atlantic drainages of the Carolinas. Malacologia 44: 23-31. [PDF]
Downs, C. A., R. T. Dillon, J. E. Fauth, and C. M. Woodley. (2001) A molecular biomarker system for assessing the health of gastropods (Ilyanassa obsoleta) exposed to natural and anthropogenic stressors. Journal of Experimental Marine Biology and Ecology 259: 189 - 214. [PDF]
Dillon, R. T. and E. P. Keferl. (2000) A survey of the pleurocerid gastropods of South Carolina. Pp. 153 - 160 in Freshwater Mollusk Symposium Proceedings (Tankersley, Warmolts, Watters, Armitage, Johnson & Butler, eds.) Ohio Biological Survey, Columbus. [PDF]
Wethington, A. R., E. R. Eastman, and R.
(2000) No premating reproductive isolation among populations
simultaneous hermaphrodite, the freshwater snail Physa.
Pp. 245 - 251 in Freshwater Mollusk
Proceedings (Tankersley, Warmolts, Watters,
Johnson & Butler, eds.) Ohio Biological Survey,
Dillon, R. T.
The inheritance of golden,
a shell color variant of Marisa cornuarietis. Malacological
Review 31/32: 155-157. [PDF]
Dillon, R.T., and C. Lydeard (1998) Divergence among Mobile Basin populations of the pleurocerid snail genus, Leptoxis, estimated by allozyme electrophoresis. Malacologia. 39: 111-119. [PDF]
Wethington, A.R., and R. T. Dillon. (1997) Selfing, outcrossing, and mixed mating in the freshwater snail Physa heterostropha: lifetime fitness and inbreeding depression. Invertebrate Biology (formerly Trans. Am. Micros. Soc.) 116: 192-199. [PDF]
Dillon, R. T., and S. A. Ahlstedt (1997) Verification of the specific status of the endangered Anthony's River Snail, Athearnia anthonyi, using allozyme electrophoresis. The Nautilus 110: 97 - 101. [PDF]
Wethington, A.R., and R.T. Dillon (1996) Gender choice and gender conflict in a non-reciprocally mating simultaneous hermaphrodite, the freshwater snail, Physa. Animal Behaviour 51: 1107-1118. [PDF]
Dillon, R.T., and A.R. Wethington (1995) The biogeography of sea islands: Clues from the population genetics of the freshwater snail, Physa heterostropha. Systematic Biology 44:401-409. [PDF]
Dayan, N.S., and R.T. Dillon (1995) Florida as a biogeographic boundary: Evidence from the population genetics of Littorina irrorata. The Nautilus 108: 49-54. [PDF]
Dillon, R.T., and A.R. Wethington (1994) Inheritance at five loci in the freshwater snail, Physa heterostropha. Biochemical Genetics 32:75-82. [PDF]
Wethington, A.R., and R.T. Dillon (1993) Reproductive development in the hermaphroditic freshwater snail, Physa, monitored with complementing albino lines. Proceedings of the Royal Society (London) B 252:109-114. [PDF]
Dillon, R.T. and J.J. Manzi (1992) Population genetics of the hard clam, Mercenaria mercenaria, at the northern limit of its range. Canadian Journal of Fisheries and Aquatic Sciences 49:2574-2578. [PDF]
Dillon, R.T. and A.R. Wethington (1992) The inheritance of albinism in a freshwater snail, Physa heterostropha. Journal of Heredity 83:208-210. [PDF]
Dillon, R.T. and A.V.C. Dutra-Clark (1992) Biomphalaria in South Carolina. Malacological Review 25: 129-130. [PDF]
Dillon, R.T. (1992) Minimal hybridization between the hard clams Mercenaria mercenaria and M. campechiensis, co-occurring in South Carolina. Bulletin of Marine Science 50:411-416. [PDF]
Wethington, A.R. and R.T. Dillon (1991) Sperm storage and evidence for multiple insemination in a natural population of the freshwater snail, Physa. American Malacological Bulletin 9: 99-102. [PDF]
Manzi, J.J., N.H. Hadley, and R.T. Dillon (1991) Hard clam, Mercenaria mercenaria, broodstocks: Growth of selected hatchery stocks and their reciprocal crosses. Aquaculture 94: 17-26. [PDF]
Hadley, N.H., R.T. Dillon, and J.J. Manzi (1991) Realized heritability of growth rate in the hard clam, Mercenaria mercenaria. Aquaculture 93: 109-119. [PDF]
Dillon, R.T. (1991) Karyotypic evolution in pleurocerid snails. II. Pleurocera, Goniobasis, and Juga. Malacologia 33: 339-344. [PDF]
Dillon, R.T. and K.B. Davis (1991) The diatoms ingested by freshwater snails: Temporal, spatial, and interspecific variation. Hydrobiologia 210: 233-242. [PDF]
Dillon, R.T., and J.J. Manzi (1989) Genetics and shell morphology in a hybrid zone between the hard clams, Mercenaria mercenaria and M. campechiensis. Marine Biology 100: 217-222. [PDF]
Dillon, R.T. (1989) Karyotypic evolution in pleurocerid snails. I. Genomic DNA estimated by flow cytometry. Malacologia 31: 197-203. [PDF]
Dillon, R.T. and J.J. Manzi
morphology of hard clams (Mercenaria) from Laguna
Madre, Texas. The
Nautilus 103:73-77. [PDF]
Dillon, R.T. (1988) Evolution from transplants between genetically distinct populations of freshwater snails. Genetica 76: 111-119. [PDF]
Dillon, R.T., and J.J. Manzi (1988) Enzyme heterozygosity and growth rate in nursery populations of the hard clam, Mercenaria. Journal of Experimental Marine Biology & Ecology 116: 79-86. [PDF]
Dillon, R.T. (1988) The influence of minor human disturbance on biochemical variation in a population of freshwater snails. Biological Conservation 43: 137-144. [PDF]
Dillon, R.T. and J.J. Manzi (1987) Hard clam (M. mercenaria) broodstocks: genetic drift and loss of rare alleles without reduction in heterozygosity. Aquaculture 60: 99-105. [PDF]
Dillon, R.T. (1987) A new Monte Carlo method for assessing the taxonomic similarity within faunal samples: Reanalysis of the gastropod fauna of Oneida Lake, NY. American Malacological Bulletin 5: 101-104. [PDF]
Dillon, R.T. (1986) Inheritance of isozyme phenotype at three loci in the freshwater snail, Goniobasis proxima: Mother-offspring analysis and an artificial introduction. Biochemical Genetics 24: 281-290. [PDF]
Dillon, R.T. (1985) Correspondence between the buffer systems suitable for electrophoretic resolution of bivalve and gastropod isozymes. Comparative Biochemistry & Physiology 82B:643-645. [PDF]
Dillon, R.T. (1984) What shall I measure on my snails? Allozyme data and multivariate analysis used to reduce the non-genetic component of morphological variance in Goniobasis proxima. Malacologia 25:503-511. [PDF]
Dillon, R.T. (1984) Geographic distance, environmental difference, and divergence between isolated populations. Systematic Zoology 33:69-82. [PDF]
Dillon, R.T. and E. F. Benfield (1982) Distribution of pulmonate snails in the New River of Virginia and North Carolina, U.S.A.: Interaction between alkalinity and stream drainage area. Freshwater Biology 12: 179-186. [PDF]
Dillon, R.T. (1981) Patterns in the morphology and distribution of gastropods in Oneida Lake, New York, detected using computer-generated null hypotheses. American Naturalist 118: 83-101. [PDF]
Dillon, R.T. and G.M. Davis (1980) The Goniobasis of southern Virginia and northwestern North Carolina: Genetic and shell morphometric relationships. Malacologia 20: 83-98. [PDF]
Dillon, R.T. (1980) Multivariate analysis of desert snail distribution in an Arizona canyon. Malacologia 19: 201-207. [PDF]
Dillon, R. T. and J. T. Vance (2018) Not Of This World, and Of It. Preached at the Unitarian Church of Charleston, SC. February 4, 2018. SciTech, The Journal of the Presbyterian Association on Science, Technology, and the Christian Faith 27(3): 6 - 8. [PDF]
Dillon, R. T. (2016) Match of Pleurocera gabbiana (Lea, 1862) to populations cryptic under P. simplex (Say, 1825). Ellipsaria 18(3): 10 - 12. [PDF]
Dillon, R. T. & J. D. Robinson (2016) The identity of the "fat simplex" population inhabiting Pistol Creek in Maryville, Tennessee. Ellipsaria 18(2): 16-18. [PDF]
Dillon, R. T. (2016) Two reproductively isolated populations cryptic under Pleurocera simplex (Say, 1825) inhabiting Pistol Creek in Maryville, Tennessee. Ellipsaria 18(2): 15-16. [PDF]
Dillon, R. T. & J. D. Robinson (2016) The hazards of DNA barcoding, as illustrated by the pleurocerid gastropods of East Tennessee. Ellipsaria 18(1): 22-24. [PDF]
Dillon, R. T. (2015) Mocking Our Lord? These Days, Daily Devotions for Living by Faith 45(3): 30July. [PDF]
Dillon, R. T. (2012) South Carolina's War on Science. Op-Ed essay in The State newspaper, Columbia, SC. April 27, 2012. Page A-13. [PDF]
Dillon, R. T. (2012) Science and the Christian Religion: A Sermon in Three Acts. Preached at Circular Congregational Church, Charleston, SC. February 12, 2012. [PDF]
Dillon, R. T.(2011) The Freshwater Gastropods of the Great Smoky Mountains National Park. A report submitted to the GSMNP Office of Inventory and Monitoring, 20Oct11. 6 pp. [PDF]
Dillon, R. T. (2011) Charles Darwin and Theodicy. SciTech, The Journal of the Presbyterian Association on Science, Technology, and the Christian Faith 20(1): 1-3. [PDF]
Dillon, R. T. (2010) Swimming With Snails. ("Point of View") College of Charleston Magazine 14: 24 -25. [PDF]
Orstan, A. & R. T. Dillon (2009) Charles Darwin the Malacologist. Mollusc World 20: 4 - 6. [PDF]
Dillon, R. T. (2008) Stonewall, Woodrow, and Me: Reflections on the other great commission. SciTech, The Journal of the Presbyterian Association on Science, Technology, and the Christian Faith 17(3): 7 - 9. [PDF]
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. 25 pp. [PDF]
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. 12 pp. [PDF]
Dillon, R. T. (2006)
251 - 260 in
Sturm, C.F., T.A. Pierce & A. Valdes (eds.), The
Mollusks: A Guide to Their Study, Collection and
Preservation. American Malacological
Pittsburgh, PA. 445 pp. [PDF]
R. T. (2005)
The Senator and the Science Committee. Reports of the the National
Science Education 25 (1/2): 4 - 5.
biology and conservation of freshwater gastropods: Introduction to the
Malacological Bulletin 19: 31.
Dillon, R. T. (2000) Science standards safe in South Carolina. Reports of the National Center for Science Education 20(1/2): 14-15.
Hadley, N.H., J.J. Manzi, A.G. Eversole, R.T. Dillon, C.E. Battey, and N.M. Peacock (1997) A Manual for the Culture of the Hard Clam Mercenaria spp. in South Carolina. SC Sea Grant Consortium, Charleston. 135 pp.
Dillon, R. T., and J.J. Manzi (1994) Managing bivalve broodstocks. World Aquaculture 24(3): 47 - 53.
Dillon, R. T. (1994) Your year is gone ... POOF! pp. 37-40 in Fainberg, A. (ed.), From the Hill to the Lab, essays celebrating 20 years of congressional science and engineering fellows. A.A.A.S., Washington, D.C.
Dillon, R. T. (1988 - 1993) "Genetics in Aquaculture", a series of twelve columns running as a regular feature in World Aquaculture.
Dillon, R. T. (1989) Journal
Complacency and complicity
in science. Serials Review 15: 80-82.
submitted or in
Wethington, A. R., R. T. Dillon, Jr., J. M. Rhett, R. Guralnick, and C. Lydeard (in prep.) Allozyme, 16S, and CO1 sequence divergence among populations of the cosmopolitan freshwater snail, Physa acuta.
Dillon, R. T. Jr, L. Schroeder, R. Hershler, and H-P. Liu (in prep) Phylogeny of the North American hydrobioid genus Fontigens.
------The Figure Below
is from Pierce, B.A. (2012) Genetics: A Conceptual Approach, Fourth Edition (W. H. Freeman, New York).
It was based on the original research of Dillon and Wethington (1992).