FWGNA Volumes 1-4
We are pleased to announce the first publications of the FWGNA Project, now available as paperback volumes directly from the publisher at a substantial discount.

Volume 1, by Dillon, Ashton, Reeves, Smith, Stewart and Watson, reports the results of a comprehensive freshwater gastropod survey conducted in Atlantic drainages from Georgia to the New York line. We provide full-color figures, a dichotomous key, range maps, and natural history notes for all 70 species and subspecies of freshwater snails recovered, updating the taxonomy to modern standards. A new, objective system of conservation status ranking is proposed, and a new species of pleurocerid snail described in the appendix.

Four Volumes
Volumes 2, 3, and 4 are collections of essays, originally appearing in blog form 2003 – 2019, now edited and rearranged thematically.  Volume 2 collects 29 essays on the systematics and evolution of the freshwater pulmonates of North America, Volume 3 comprises 37 essays on the systematics and evolution of the prosobranchs, and Volume 4 collects 38 essays reviewing ecological and biogeographical themes.  These volumes are intended to support and augment the scientific results reported in Volume 1.

The total retail price for the four volumes purchased individually is $145.80. But we have arranged a special package deal with the publisher for friends of the FWGNA project, available online

Hit the link below to "buy yours now."  That will take you to my author's profile page at  At the bottom of my profile page you will find four "titles by this author."  Hit each of those links in turn, and add each of those titles to your shopping cart, separately.  Then proceed to checkout.  At the checkout page you will find a box to enter a "coupon code." Apply the coupon code FWGNA4 to each of the four volumes.  This will discount your price to $99.95 for the set ... a bargain!

Buy yours now!

FWGNA Circulars

Dillon, R.T., Jr. (2012) Toward the scientific ranking of conservation status.  FWGNA Circular 1: 1 - 13.  [pdf] The data are obsolete, but the introduction and methods remain important.

Dillon, R. T., Jr. (2018) Welcome to the mystery snail color genetics project!  FWGNA Circular 7: 1 - 13.  [pdf] In 2018 I initiated a crowdsourced effort to work out the inheritance of color polymorphism in the common aquarium pet, Pomacea diffusa.  This circular is a hardcopy version of an 11-page website I put online to guide potential volunteers through the experimental design.  For more, see my blog post of [6June23].

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

Dillon, R.T., Jr. (2021) Two keen Campeloma quizzes.  FWGNA Circular 3: 1 - 3. [pdf] Mostly just fun, but there's a serious subtext.  For the context, see my blog post of [7May21].

Liu, H-P. and R.T. Dillon, Jr. (2021) Resolving the species status of the Surprise Valley Pyrg (Pyrgulopsis gibba) and Vinyard Pyrg (Pyrgulopsis vinyardi).  Report to Stantec Environmental Consulting.  FWGNA Circular 6: 1 - 5. [pdf]  For background, see my blog post of [7Sept22]. 

Dillon, R.T., Jr. (2022) The biogeography of North American freshwater gastropods, v1.0. FWGNA CIrcular 4: 1 - 5. [pdf] Originally published online in 2019, and rendered obsolete in 2022 by the publication of biogeography v2.0.  But the methodology remains interesting.

Wethington, A.R., J.M. Rhett, and R.T. Dillon, Jr. (2022) Allozyme, 16S, and CO1 sequence divergence among populations of the cosmopolitan freshwater snail, Physa acuta.  FWGNA Circular 5: 1 - 36. [pdf] Previously unpublished, this manuscript reports the first evidence of cytoplasmic male sterility in Physa.  For more, see my blog post of [9June22].