{{Short description|Genus of gastropods}} {{Automatic taxobox | image = Marstonia comalensis shell.png | image_caption = shell of ''Marstonia comalensis'' | image2 = Pyrgulopsis scalariformis shell.jpg | image2_caption = Apertural view of a shell of ''Marstonia scalariformis''. | taxon = Marstonia | authority = Baker, 1926<ref>Baker H. B. (1926). ''Trans. Wisconsin Acad. Sci. Arts'' '''22''': 195.</ref> | diversity_link = | diversity_ref = <ref>MolluscaBase eds. (2021). MolluscaBase. Marstonia F. C. Baker, 1926. Accessed at: http://molluscabase.org/aphia.php?p=taxdetails&id=719377 on 2023-10-25</ref> | diversity = 16 valid species }}
'''''Marstonia''''' is a genus of freshwater snails with a gill and an operculum, aquatic gastropod molluscs in the family Hydrobiidae.
==Distribution == Species in the genus ''Marstonia'' are distributed in springs, streams and lakes in eastern North America.<ref name="Hershler 2011"/> Most of these species have extremely narrow geographic ranges and consequently have become a focus of conservation activities; two are federally listed as endangered and others are variously listed by state wildlife agencies.<ref name="Hershler 2011"/>
== Description == The freshwater gastropod genus ''Marstonia'' is composed of 15 small (shell height < 5.0 mm), ovate- to elongate-shelled species.<ref name="Hershler 2011"/> ''Marstonia'' differs from the other eight North American nymphophiline genera in that the (female) oviduct and bursal duct join well in front of (instead of behind) the posterior wall of the pallial cavity.<ref name="Hershler 2011"/> It has also been resolved as a well supported sub-clade within its subfamily based on mtDNA sequences.<ref name="Hershler 2011"/>
== Species == Eastern North American species of ''Pyrgulopsis''<ref>Hershler R. (1994). "A review of the North American freshwater snail genus ''Pyrgulopsis'' (Hydrobiidae)". ''Smithsonian Contributions to Zoology'' '''554''': 1-115. [http://si-pddr.si.edu/dspace/bitstream/10088/5139/2/SCtZ-0554-Lo_res.pdf PDF] {{Webarchive|url=https://web.archive.org/web/20110718103828/http://si-pddr.si.edu/dspace/bitstream/10088/5139/2/SCtZ-0554-Lo_res.pdf |date=2011-07-18 }}.</ref> are considered to be in separate genus ''Marstonia'' according to Thompson & Hershler (2002).<ref>''Marstonia'' http://www.natureserve.org accessed 25 July 2009. (See "Concept References" in each ''Marstonia'' species.)</ref>
* ''Marstonia agarhecta'' (F. G. Thompson, 1969) - synonym: ''Pyrgulopsis agarhecta'' F. G. Thompson, 1969 - Ocmulgee marstonia * ''Marstonia arga'' - F. G. Thompson, 1977 - synonym: ''Pyrgulopsis arga'' (F. G. Thompson, 1977) - ghost marstonia * ''Marstonia castor'' F. G. Thompson, 1977 - synonym: ''Pyrgulopsis castor'' (F. G. Thompson, 1977) - beaverpond marstonia * ''Marstonia halcyon'' F. G. Thompson, 1977 - synonym: ''Pyrgulopsis halcyon'' (F. G. Thompson, 1977) - halcyon marstonia * ''Marstonia hershleri'' (F. G. Thompson, 1995) - synonym: ''Pyrgulopsis hershleri'' F. G. Thompson, 1995 - Coosa pyrg * ''Marstonia letsoni'' (Walker, 1901) - synonym: ''Pyrgulopsis letsoni'' (Walker, 1901) - gravel pyrg * ''Marstonia lustrica'' (Pilsbry, 1890) - synonym: ''Pyrgulopsis lustrica'' (Pilsbry, 1890) - boreal marstonia<ref>{{Cite web |url=http://www.mass.gov/dfwele/dfw/nhesp/species_info/nhfacts/marstonia_lustrica.pdf |title=Archived copy |access-date=2009-07-24 |archive-date=2009-12-05 |archive-url=https://web.archive.org/web/20091205033625/http://www.mass.gov/dfwele/dfw/nhesp/species_info/nhfacts/marstonia_lustrica.pdf |url-status=dead }}</ref> * ''Marstonia ogmorhaphe'' (F. G. Thompson, 1977) - synonym: ''Pyrgulopsis ogmoraphe'' (F. G. Thompson, 1977) - royal springsnail * ''Marstonia olivacea'' (Pilsbry, 1895) - synonym: ''Pyrgulopsis olivacea'' (Pilsbry, 1895) - olive marstonia, it may be extinct<ref name="Hershler 2011"/> * ''Marstonia ozarkensis'' (Hinkley, 1915) - synonym: ''Pyrgulopsis ozarkensis'' Hinkley, 1915 - Ozark pyrg, it may be extinct<ref name="Hershler 2011"/> * ''Marstonia pachyta'' F. G. Thompson, 1977 - synonym: ''Pyrgulopsis pachyta'' (F. G. Thompson, 1977) - armored marstonia * ''Marstonia scalariformis'' (Wolf, 1869) - synonym: ''Pyrgulopsis scalariformis'' (Wolf, 1869) - moss pyrg
Other species of ''Marstonia'' include: * ''Marstonia angulobasis'' F. G. Thompson, 2005 - angled marstonia * ''Marstonia comalensis'' (Pilsbry & Ferriss, 1906) - Comal siltsnail * ''Marstonia gaddisorum'' F. G. Thompson, 2004 - Gaddis marstonia * {{extinct}}''Marstonia inflata'' H.-J. Wang, 1977
Although ''Marstonia'' has been reviewed four times since 1978 (Thompson 1978, Hershler 1994, Thompson & Hershler 2002, Hershler & Liu 2011), three of its congeners have been little studied beyond their original descriptions and their anatomy is unknown.<ref name="Hershler 2011"/> Two of these — ''Marstonia olivacea'', ''Marstonia ozarkensis'' — may be extinct and thus will likely remain incertae sedis.<ref name="Hershler 2011"/>
== References == This article incorporates CC-BY-3.0 text from the reference <ref name="Hershler 2011">Hershler R. & Liu H.-P. (2011). "Redescription of ''Marstonia comalensis'' (Pilsbry & Ferriss, 1906), a poorly known and possibly threatened freshwater gastropod from the Edwards Plateau region (Texas)". ''ZooKeys'' '''77''': 1-16. {{doi|10.3897/zookeys.77.935|doi-access=free}}.</ref> {{Reflist}}
== Further reading == * Thompson F. G. & Hershler R. (2002). "Two genera of North American freshwater snails: ''Marstonia'' Baker, 1926, resurrected to generic status, and ''Floridobia'', new genus (Prosobranchia: Hydrobiidae: Nymphophilinae)." ''The Veliger'' '''45'''(3): 269–271.
{{Commons category}} {{Taxonbar|from=Q3139709}} {{Authority control}}
Category:Hydrobiidae Category:Gastropod genera Category:Marstonia Category:Taxa named by Horace Burrington Baker