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Taxonomy

Common Name: SHEEPNOSE

Phylum: MOLLUSCA

Class: BIVALVIA

Order: UNIONOIDA

Family: UNIONIDAE

Genus: PLETHOBASUS

Species: CYPHYUS

Taxonomic Authority: (RAFINESQUE)

Taxonomy References: 016 , 002 , 004 , 005 , 007 , 010

Status

FEDERAL ENDANGERED
STATE ENDANGERED
STATE RANK S2
GLOBAL RANK G3

Status References: 015 , 001 , 002 , 003

Habitat Summary

"Found in medium to large rivers with gravel or mixed sand and gravel substrate."

Primary Habitat: "Aquatic - river/stream"

References: 002 , 003 , 005 , 006 , 007

Distribution

General Occurrence in State:

"Is found in the east-central part of Missouri *05*."

County Occurance

County Occurence
Known	Likely	Unknown	Not Likely	Historic	Extirpated
CRAWFORD		ADAIR
FRANKLIN		ANDREW
GASCONADE		ATCHISON
JEFFERSON		AUDRAIN
LACLEDE		BARRY
MARION		BARTON
ST. LOUIS		BATES
		BENTON
		BOLLINGER
		BOONE
		BUCHANAN
		BUTLER
		CALDWELL
		CALLAWAY
		CAMDEN
		CAPE GIRARDEAU
		CARROLL
		CARTER
		CASS
		CEDAR
		CHARITON
		CHRISTIAN
		CLARK
		CLAY
		CLINTON
		COLE
		COOPER
		DADE
		DALLAS
		DAVIESS
		DEKALB
		DENT
		DOUGLAS
		DUNKLIN
		GENTRY
		GREENE
		GRUNDY
		HARRISON
		HENRY
		HICKORY
		HOLT
		HOWARD
		HOWELL
		IRON
		JACKSON
		JASPER
		JOHNSON
		KNOX
		LAFAYETTE
		LAWRENCE
		LEWIS
		LINCOLN
		LINN
		LIVINGSTON
		MACON
		MADISON
		MARIES
		MCDONALD
		MERCER
		MILLER
		MISSISSIPPI
		MONITEAU
		MONROE
		MONTGOMERY
		MORGAN
		NEW MADRID
		NEWTON
		NODAWAY
		OREGON
		OSAGE
		OZARK
		PEMISCOT
		PERRY
		PETTIS
		PHELPS
		PIKE
		PLATTE
		POLK
		PULASKI
		PUTNAM
		RALLS
		RANDOLPH
		RAY
		REYNOLDS
		RIPLEY
		SALINE
		SCHUYLER
		SCOTLAND
		SCOTT
		SHANNON
		SHELBY
		ST. CHARLES
		ST. CLAIR
		ST. FRANCOIS
		STE. GENEVIEVE
		STODDARD
		STONE
		SULLIVAN
		TANEY
		TEXAS
		VERNON
		WARREN
		WASHINGTON
		WAYNE
		WEBSTER
		WORTH
		WRIGHT

References for distribution: 005 , 006 , 007 , 012

Distribution by Watersheds

Miss. R. from Des Moines R. to MO. R.; and North R.
Meramec R.
Bourbeuse R.
Big R.
Gasconade R. from Headwaters to Big Piney R.

Comments: "Widely distributed in the Mississippi river drainages. Meramec river may have the best remaining habitat for this species *03*."

Distribution by Ecoregions

Central Till Plains, Ozark Highlands

Comments: ""

Distribution by Potential Natural Vegetation

Bluestem Prairie/Oak Hickory Forest
Oak-Hickory Forest

Distribution by Natural Divisions of Missouri

Glaciated Plains: Eastern
Ozark Border: Mississippi River
Ozark: Upper Ozark

Habitat Associations

Species is associated with "Aquatic" habitats.

National Wetlands Inventory Association:

Riverine

Aquatic Associations:

"Riverine, upper perennial", "Rock bottom, boulder"
"Riverine, upper perennial", "Unconsolidated bottom, cobble/gravel"
"Riverine, upper perennial", "Unconsolidated bottom, sand"
"Riverine, upper perennial", "Unconsolidated bottom, mud"

References for Aquatic Associations: 002 , 003 , 005 , 006 , 007

Habitat Types:

References for Habitat Types:

Terrestrial Natural Communities:

References for Terrestrial Natural Communities:

Food Habits

Trophic Level:

"Omnivore"

Larval Food Habits

Comments for larval food habits:
""

References for larval food habits:

Juvenile Food Habits

Comments for Juvenile Food Habits:
""

References Juvenile Food Habits

Adult Food Habits

Algae; Not Specified
Protozoans; Not Specified
Other Microorganisms; Not Specified
Bacillariophyceae (diatoms); Not Specified

Comments for Adult Food Habits:
""

References Adult Food Habits 011

Niche Requirements

Egg Niche Requirements

References for egg niches requirements:

Feeding Larvae Niche Requirements

Host specified in comments(00680)

References for feeding larvae niche requirements: 005

Resting Larvae Niche Requirements

Substrate (not bottom type): mud or silt
Substrate (not bottom type): sand substrate
Substrate (not bottom type): rock substrate
Substrate specified in comments(00080)
Relation to substrate: occurs in substrate (penetrating)
Bottom type: mud or silt
Bottom type: sand
Bottom type: pebble
Bottom type: gravel
Bottom type: boulders
Gradient: low
Gradient: moderate
Current velocity: no noticable current
Current velocity: slow current
Current velocity: moderate current
Current velocity: swift current
Current velocity specified in comments(00150)
Water depth: shallow
Water depth: deep
Water depth specified in comments(00230)
Stream width specified in comments(00265)
Natural features: riffles

References for resting Larvae niche requirements: 005

Feeding Juvenile Niche Requirements

References for feeding juvenile niche requirements:

Resting Juvenile Niche Requirements

References for resting juvenile niche requirements:

Breeding Adult Niche Requirements

References for feeding Adult niche requirements: 002 , 005 , 006 , 007 , 008 , 010

Feeding Adult Niche Requirements

References for feeding adult niche requirements: 002 , 005 , 006 , 007 , 008 , 010

Resting Adult Niche Requirements

References for resting adult niche requirements:

Niche Requirement Summary

Bottom type: boulders
Bottom type: gravel
Bottom type: mud or silt
Bottom type: pebble
Bottom type: sand
Current velocity specified in comments(00150)
Current velocity: moderate current
Current velocity: no noticable current
Current velocity: slow current
Current velocity: swift current
Gradient: low
Gradient: moderate
Host specified in comments(00680)
Natural features: riffles
Relation to substrate: occurs in substrate (penetrating)
Stream width specified in comments(00265)
Substrate (not bottom type): mud or silt
Substrate (not bottom type): rock substrate
Substrate (not bottom type): sand substrate
Substrate specified in comments(00080)
Water depth specified in comments(00230)
Water depth: deep
Water depth: shallow

Comments about Life History:

Code	Comment
003	The host fish for glochidia is the sauger (stizostedion canadense) 05,07,10.
007	Reproductive period is May-June 05,06 or May-July 10.
099	Short-termed brooded with ectobranchous marsupia 07.
037	Adults are mostly sessile; may be forced out of substrate and washed downstream by floods. Dispersal of larvae (glochidia) occurs while encysted on their hosts 07.

Life History Information

Dispersal specified in comments(037)
Other life history information specified in comments(099)
Seasonal distribution in state: all seasons
Closely associated plant or animal species specified in comments(003)
Foraging strategy: filtering
Foraging sites: feed on bottom of stream, lake or pond
Breeding season specified in comments(007)

Comments about Life History:

Code	Comment
003	The host fish for glochidia is the sauger (stizostedion canadense) 05,07,10.
007	Reproductive period is May-June 05,06 or May-July 10.
099	Short-termed brooded with ectobranchous marsupia 07.
037	Adults are mostly sessile; may be forced out of substrate and washed downstream by floods. Dispersal of larvae (glochidia) occurs while encysted on their hosts 07.

References for life history: 005 , 006 , 007 , 008 , 010

Management

Beneficial Management Practices:

Water - control sedimentation
Water - control pollution (thermal, physical, chemical)
Water - control aquatic animals
Water - exclude livestock from water
Water - other (specify in comments)

Beneficial Management References: 003

Adverse Managment Practices:

Water - application of herbicides
Water - dredging and filling
Water - navigational improvements (channelization, dams, locks)
Water - stream channelization
Water - drainage of wetlands, marshes, ponds, lakes
Water - other (specify in comments)

Adverse Management References: 003

Comments on Management:
Adverse: siltation, pollution, impoundments, zebra mussels, fertilizer, agricultural run-off, domestic livestock *03*.

References for Management Comments: 003

References

Reference Code	Citation
001	Missouri Natural Heritage Program. 2007. Missouri Species and Communities of Conservation Concern Checklist. Missouri Department Of Conservation. Jefferson City, Missouri. 51 Pp.
002	Illinois Natural History Survey. 1997. Plethobasus Cyphyus (Rafinesque, 1820) Sheepnose. Http://Www.Inhs.Uiuc.Edu/Cbd/Musselmanual/ Page50_1.Html 2 November 2000.
003	Natureserve: An Online Encyclopedia Of Life [Web Application]. 2000. Version 1.0. Arlington (Va): Association For Biodiversity Information. Available: Http://Www.Natureserve.Org/. (Accessed: November 7, 2000).
004	Williams, J.D., A.E. Bogan, R.S. Butler, K.S. Cummings, J.T. Garner, J.L. Harris, N.A. Johnson and G.T. Watters. 2017. A revised list of the freshwater mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater Mollusk Biology and Conservation 20:33-58.
005	Oesch, R.D. 1995. Missouri Naiades. A Guide To The Mussels Of Missouri. Second Edition. Missouri Dept. Of Conservation. Jefferson City, Missouri. 271 Pp.
006	Buchanan, A. C. 1980. Mussels (naiades) of the Meramec River Basin. Missouri Dept. of Conservation Aquatic Ser. No. 17. Jefferson City, MO. 76 pp.
007	Unpb Missouri Department of Conservation Heritage Database. P.O. Box 180, Jefferson City, Mo 65102.
008	Gordon, M.E. and J.B. Layzer. 1989. Mussels (Bibalvia: Unionoidea) Of The Cumberland River Review Of Life Histories And Ecological Relationships. Biological Report 89(15): 1-99. As Cited In (06).
009	Surber, T. 1913. Notes On The Natural Hosts Of Freshwater Mussels. Bull. Us Bur. Fish. 32: 101-116. As Cited In (07).
010	Baker, F.C. 1928. The fresh-water mollusca of Wisconsin. Part II. Pelecypoda. Bull. Univ. Wisconsin, Bull. 70, II. WI Geol. and Nat. Hist. Surv. Gen. Ser. 1301, 495 pp. (cited in ref. 001)
011	Allen, W.R. 1914. The Food And Feeding Habits Of Freshwater Mussels. Biol. Bull. 27(3):127-139.
012	Unpb Bruenderman, S. Mussel Occurrence Database. Missouri Dept. Of Conservation, 1110 S. College Ave., Columbia, Mo 65201 (573-882-9880).
013	Unpb Sternburg, J. MO Dept. of Conservation, P.O. Box 180, Jefferson City, MO 65102 (573-751-4115)
014	Pflieger, W.L. 1989. Aquatic Community Classification System For Missouri. Mo Dept. Of Conservation. Aquatic Series No. 19. 70 Pp + Supplement.
015	Missouri Natural Heritage Program. 2013. Missouri Species and Communities of Conservation Concern Checklist. Missouri Department of Conservation. Jefferson City, MO. pp. 52.
016	Freshwater Mollusk Conservation Society (FMCS). 2021. The 2021 checklist of freshwater mussels. https://molluskconservation.org/Library/Committees/Names/Appendix_1_Bivalves_Revised_Names_List_20210825.pdf.