Utterbackia imbecillis

Utterbackia imbecillis
Conservation status
Least Concern  (IUCN 3.1) [1]
Secure  (NatureServe) [2]
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Unionida
Family:	Unionidae
Genus:	Utterbackia
Species:	U. imbecillis
Binomial name
Utterbackia imbecillis (Say, 1829)
Synonyms [3]
Anodon hordaGould, 1855 Anodonta (Lastena) ohiensis horda(Gould, 1855) Anodonta (Utterbackia) imbecilis(Say, 1829) Anodonta henryanaLea, 1860 Anodonta henryianaLea, 1857 Anodonta imbecillisSay, 1829 Anodonta incertaLea, 1834 Anodonta phalenaDe Gregorio, 1914 Margarita (Anodonta) incerta(Lea, 1834) Margaron (Anodonta) henryana(Lea, 1857) Margaron (Anodonta) imbecillis(Say, 1829) Utterbackia henryana(Lea, 1857) Utterbackia imbecilis(Say, 1829) Utterbackia imbecillis var. fuscaBaker, 1927

Utterbackia imbecillis, commonly known as the paper pondshell, papershell, or paper floater, is a species of freshwater mussel in the family Unionidae. Native to North America, it is a widespread species distributed in much of the eastern United States as well as Ontario and Quebec in Canada and Tamaulipas in Mexico.

Taxonomy and history

This species was described by Thomas Say in 1829 as Anodonta imbecillis, based on a type specimen from the Wabash River in New Harmony, Indiana. ^{[4] [5] [6]} This type specimen, and most of Say's other material, is believed to be lost, however, a neotype designated by Fritz Haas in 1930 is held in the collection of the Naturmuseum Senckenberg in Germany. The specific epithet imbecillis is derived from the Latin word imbecillus, meaning "feeble" or "weak", in reference to the unusually thin and fragile shell of this species. ^[5]

Frank Collins Baker erected the genus Utterbackia for this species in 1927, combining the binomial as Utterbackia imbecillis. ^{[5] [7]} Baker noted that, unlike mussels in the genus Anodonta, U. imbecillis is hermaphroditic, has unusually flat umbones, and is not an obligate parasite in the glochidia stage. ^[7]

In English, this species is commonly known as the paper pondshell, papershell, or paper floater, while in French it is commonly known as Utterbackie papyracée. ^{[2] [5]}

Description

It is characterized by its unusually thin shell, ^[4] from which it derives its species name, ^[8] meaning "fragile".

Distribution and habitat

Utterbackia imbecillis has a large range across eastern North America, including the provinces of Quebec and Ontario in Canada and the states of Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Mexico, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Virginia, West Virginia, and Wisconsin and the District of Columbia in the United States. ^{[1] [2]} The southernmost point of its range extends to the state of Tamaulipas in northeastern Mexico. ^[5] It is a freshwater species that inhabits both natural and artificial lakes, ponds, creeks, rivers, and reservoirs, preferring a sandy or muddy substrate. ^[2]

References

1. Cummings, K. & Cordeiro, J. (2012). "Utterbackia imbecillis". IUCN Red List of Threatened Species . 2012 e.T189156A1920006. doi: 10.2305/IUCN.UK.2012-1.RLTS.T189156A1920006.en . Retrieved 6 August 2023.
2. NatureServe. "Utterbackia imbecillis". NatureServe Explorer. Arlington, Virginia. Retrieved 8 January 2025.
3. Bieler R, Bouchet P, Gofas S, Marshall B, Rosenberg G, La Perna R, Neubauer TA, Sartori AF, Schneider S, Vos C, ter Poorten JJ, Taylor J, Dijkstra H, Finn J, Bank R, Neubert E, Moretzsohn F, Faber M, Houart R, Picton B, Garcia-Alvarez O (eds.). "Utterbackia imbecillis (Say, 1829)". MolluscaBase. World Register of Marine Species . Retrieved 8 January 2025.
4. Say, Thomas (1840). Descriptions of some new terrestrial and fluviatile shells of North America, 1829, 1830, 1831. New Harmony, Indiana. p. 13. doi:10.5962/bhl.title.8024. OCLC   12404763 – via Biodiversity Heritage Library.
5. Watters, G. Thomas; Hoggarth, Michael A.; Stansbery, David H. (2009). The Freshwater Mussels of Ohio. Columbus: Ohio State University Press. pp. 321–326. ISBN   978-0-8142-1105-2. OCLC   741494963 – via Project MUSE.
6. Parmalee, Paul Woodburn; Bogan, Arthur E. (1998). The Freshwater Mussels of Tennessee (1st ed.). Knoxville: University of Tennessee Press. pp. 242–244. ISBN   978-1-57233-013-9 – via ResearchGate.
7. Baker, Frank Collins (1927). "On the Division of the Sphaeriidae into Two Subfamilies: And the Description of a New Genus of Unionidae, with Descriptions of New Varieties". American Midland Naturalist . 10 (7): 220. doi: 10.2307/2993164 . ISSN   0003-0031. JSTOR   2993164. LCCN   13003548. OCLC   5731039.
8. "Imbecile (adj)". Etymonline. Retrieved 3 February 2026.

• Haag, W. R. (2012). North American Freshwater Mussels: Natural History, Ecology, and Conservation. Cambridge University Press. ISBN   978-0521199384
• Vidrine, M. F. (1993) The historical distributions of fresh-water mussels in Louisiana. Gail O. Vidrine Collectibles. ISBN   978-0963730404.