Overview of the North American Terrestrial Gastropod Fauna*

Abstract

A revised database of terrestrial gastropods from North America north of Mexico was assembled in the spring of 2012, which included not only all likely species-level entities, updated family and naturalized exotic assignments, but also shell and body size data. Analyses of these reveal that: (1) the fauna represents approximately 1,200 species, and is dominated by the Polygyridae, Helminthoglyptidae, and Vertiginidae. This number is surprisingly small, with other land masses of ½ to 1/100 th the size possessing a larger fauna; (2) naturalized species make up 6% of the total fauna; (3) while slugs represent only 7% of the native fauna, they constitute over 1/3 of the naturalized fauna; (4) the accumulation curve for recognized species is sigmoidal, with current rates being the lowest experienced in 200 years. As a result, it appears that only 150-300 net additional taxa may await description, with the principle future taxonomic activity being revisionary work; (5) like other faunas, both native and naturalized land snails in North America possess bimodal height/width ratios; (6) native land snails possess a bimodal, right-skewed biovolume distribution along a log axis, which differs greatly from the unimodal left-skewed distribution typical of many other taxa groups; and, (7) the distribution of species within families and genera, and of the number of species described by a given researcher all possess Power Law/Log Normal distributions characteristic of complex adaptive systems.

Living on the edge: comparative phylogeography and phylogenetics of Oreohelix land snails at their range edge in Western Canada

“…Terrestrial 'mountain snails' in the genus Oreohelix (Stylommatophora; Oreohelicidae) are large-bodied (up to 2 cm in shell diameter), air-breathing, and conspicuous components of the terrestrial mollusc community in high-elevation habitats in western North America [12,13]. The 80 described species within the genus [13] are found in a broad range of habitats that extend northsouth from Canada to northern Mexico, and east-west from the Black Hills in South Dakota to the Sierra Nevada Mountains in California. Within this continentwide distribution, individual species vary extensively in the breadth of their habitat requirements and in their patterns of endemicity.…”

Population genetic structure of Helix pomatia L. (Mollusca, Pulmonata) from the southeastern and eastern parts of the range

“…In addition, the mollusk has been introduced in a number of cities such as St. Petersburg, Kursk, Moscow, and Kharkiv [4][5][6][7]. There are reports on introduction of H. pomatia in Finland [8] and the United States [9], where currently the species is regis tered in the American Malacological Bulletin on the list of N orth American terrestrial gastropods [10].…”

Caveat consumptor notitia museo: Let the museum data user beware

“…Maximum shell dimension for each species was based on Nekola (). In addition, the North American species richness of families was determined using Nekola () in conjunction with Bouchet and Rocroi () and Schileyko (). County‐scale demographic and geographic data were obtained via the Texas Open Data Portal (https://data.texas.gov/).…”