Essays on the Pulmonates

Populations of basommatophoran pulmonate snails are common and widespread throughout American freshwaters, especially in lakes, ponds, ditches, and calmer riverine margins. They are typically weedy in their life history adaptation, fast-growing and rapidly-spreading to colonize new habitats, with the ability to self-fertilize. The present volume is a collection of 29 essays on pulmonate systematics and evolution, originally published in blog form between 2006 - 2018, edited and reorganized thematically. Themes include the old tension between genetic and environmental components of morphological variance, the more recent tension between classifications based on morphology and those based on molecular tools, and the modern tension between gene trees and species trees. An historical perspective is adopted throughout, aiming to place nineteenth and twentieth century research into a twenty-first century context. Volume I in this series analyzed the results of a scientific survey of the freshwater gastropod fauna of the Atlantic drainages from Georgia to the New York line. The essays collected here in Volume II (Pulmonates), together with those in Volume III (Prosobranchs) and Volume IV (Ecology and Biogeography), will be essential companions to Volume 1, as well as to additional volumes on the gastropod faunas of interior drainages forthcoming.