Biogeography of Great Basin aquatic snails of the genus Pyrgulopsis

Publication Type:

Book Chapter

Authors:

Source:

Great Basin aquatic systems history. (Smithsonian contributions to the earth sciences; no. 33), Smithsonian Institution Press, Washington, DC, p.255-276 (2002)

Call Number:

B02HER01IDUS

URL:

https://www.researchgate.net/profile/Peter_Wigand/publication/261596660_Great_Basin_Vegetation_History_and_Aquatic_Systems_The_Last_150000_Years/links/0deec537d90183bdfb000000/Great-Basin-Vegetation-History-and-Aquatic-Systems-The-Last-150-000-Years.pdf

Keywords:

Great Basin, Pyrgulopsis, springsnail

Abstract:

Snails of the genus Prygulopsis (Caenogastropoda: Hydrobiidae) are among the richest elements of aquatic biodiversity in the Great Basin (80 Holocene species), with most species endemic to single springs, spring systems, or drainage basins. Pyrgulopsis is an old Great Basin group, with a fossil record extending into the late Miocene (Truckee Formation). These tiny, gill-breathing gastropods (commonly known as springsnails) are obligately aquatic throughout their life cycle which, together with the above features, suggests that their biogeographic patterns are highly informative with respect to late Cenozoic hydrographic history. Distributions of Pyrgulopsis species define seven regions of endemism within the Great Basin. Five of these correspond to drainages harboring concentrations of other endemic aquatic biota (Death Valley system, Lahontan Basin, Bonneville Basin, Railroad Valley, upper White River basin), whereas snail endemism in Dixie and Steptoe basins appears to be unique. Each of the three largest regions (Death Valley system, Lahontan Basin, Bonneville Basin) contains two or three subregions of Pyrgulopsis endemism, most of which are not paralleled by other aquatic biota. Pyrgulopsis biogeography in part conforms to currently accepted interpretations of pluvial drainage in the Great Basin, but locally suggests different, presumably older relationships. Various historical relationships with adjacent external drainages are implied, although snail biogreography provides surprisingly little evidence of prior linkage with the Sacramento and upper Colorado River basins. In contrast to the fish-hook track, which is attributed to various mollusks and fishes and links the Snake River basin with the eastern Bonneville and western Lahonta basins, Pyrgulopsis provides evidence of more continuous prior drainage integration across the northern boundary of the Great Basin.