Snuffbox mussel (Epioblasma triquetra)

Federal Register | Recovery | Critical Habitat | Conservation Plans | Petitions | Life History

Listing Status:   


General Information

The snuffbox is a small- to medium-sized mussel, with males reaching up to 2.8 in (7.0 cm) in length (Cummings and Mayer 1992, p. 162; Parmalee and Bogan 1998, p. 108). The maximum length of females is about 1.8 in (4.5 cm) (Parmalee and Bogan 1998, p. 108). The shape of the shell is somewhat triangular (females), oblong, or ovate (males), with the valves solid, thick, and very inflated. The beaks are located somewhat anterior of the middle, and are swollen, turned forward and inward, and extended above the hingeline (Cummings and Mayer 1992, p. 162). Beak sculpture consists of three or four faint, double-looped bars (Cummings and Mayer 1992, p. 162; Parmalee and Bogan 1998, p. 108). The anterior end of the shell is rounded, and the posterior end is truncated, highly so in females. The posterior ridge is prominent, being high and rounded, while the posterior slope is widely flattened. The posterior ridge and slope in females is covered with fine ridges and grooves, and the posterioventral shell edge is finely toothed (Cummings and Mayer 1992, p. 162). The ventral margin is slightly rounded in males and nearly straight in females. Females have recurved denticles (downward curved tooth-like structures) on the posterior shell margin that aid in holding host fish (Barnhart 2008, p. 1). The periostracum (external shell surface) is generally smooth and yellowish or yellowish-green in young individuals, becoming darker with age. Green, squarish, triangular, or chevron-shaped marks cover the umbone (the inflated area of the shell along the dorsal margin), but become poorly delineated stripes with age. Internally, the left valve has two high, thin, triangular, emarginate pseudocardinal teeth (the front tooth being thinner than the back tooth) and two short, strong, slightly curved, and finely striated lateral teeth. The right valve has a high, triangular pseudocardinal tooth with a single short, erect, and heavy lateral tooth. The interdentum (a flattened area between the pseudocardinal and lateral teeth) is absent, and the beak cavity is wide and deep. The color of the nacre is white, often with a silvery luster, and a gray-blue or gray-green tinge in the beak cavity. Key characters useful for distinguishing the snuffbox from other species include its unique color pattern, shape (especially in females), and high degree of inflation.

Current Listing Status Summary
Status Date Listed Lead Region Where Listed
2012-03-15 Great Lakes-Big Rivers Region (Region 3) Wherever found

» Federal Register Documents

Federal Register Documents
Date Citation Page Title
1991-11-21 00:00:00.0 56 FR 58804 58836 ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species; 56 FR 58804 58836
2012-02-14 00:00:00.0 77 FR 8632 8665 Determination of Endangered Status for the Rayed Bean and Snuffbox Mussels Throughout Their Ranges: Final rule.
2010-11-02 00:00:00.0 75 FR 67552 67583 Listing the Rayed Bean and Snuffbox as Endangered; Proposed Rule
2011-09-27 00:00:00.0 76 FR 59836 59862 Partial 90-Day Finding on a Petition To List 404 Species in the Southeastern United States as Endangered or Threatened With Critical Habitat
1994-11-15 00:00:00.0 59 FR 58982 59028 ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species.

» Recovery

No recovery information is available for the Snuffbox mussel.

» Critical Habitat

No critical habitat rules have been published for the Snuffbox mussel.

» Conservation Plans

No conservation plans have been created for Snuffbox mussel.

» Petitions

» Life History

No Life History information has been entered into this system for this species.

» Other Resources

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ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.

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