Distribution ⁴

Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) This species is widespread in the eastern U.S., occurring throughout much of the Mississippi River system, and portions of the Great Lakes drainage (Mirarchi et al., 2004). Distribution includes the entire Mississippi River drainage from the St. Lawrence River and its tributaries south to northern Louisiana and west to the tributaries of the Red River, Oklahoma (Parmalee and Bogan, 1998). In Canada, it is common in the Great Lakes and their tributaries from Lake Michigan to Lake Erie, uncommon in Lake Ontario and the St. Lawrence River (Clarke, 1981).

Habitat ⁵

Habitat Type: Freshwater

Comments: It occurs in medium streams to large rivers primarily in shoal habitat of unimpounded streams and rivers but can occasionally be found in tailwaters of dams (Tennessee River) in water 4 to 8 m deep and can even be found in lakes under some conditions (Williams et al., 2008).

Iucn red list assessment ⁶

Morphology ⁷

The spike is up to 12.7 cm (5 inches) long , and is elongate and elliptical. The shell is usually fairly thick and compressed. The   anterior end is rounded, the posterior end rounded to slightly pointed. The dorsal and ventral margins are straight to slightly curved.

Umbos are low, and not raised above the hinge line. The beak sculpture has three or four parallel ridges.

The periostracum (outer shell layer) is smooth, green-brown in younger specimens, dark brown to black in older specimens.

On the inner shell, the   left valve has two divergent, erect, triangular and striated   pseudocardinal teeth. The two lateral teeth are short to slightly curved, and rough. The right valve has one large, erect, triangular and serrated pseudocardinal tooth, with a small tooth to the anterior end. The single lateral tooth on the right valve is slightly curved and rough.

The beak cavity is shallow. Although the nacre is almost always purple, and only occasionally white.

In Michigan, this species is most easily confused with the eastern elliptio in northern Michigan. The eastern ellipse is rhomboidal and more compressed. In lower Michigan, similar species include the black sandshell and the kidneyshell. The black sand shell has a thicker shell and the posterior end is more pointed or saber-shaped. Besides being more of a kidney shape, the posterior end of the kidneyshell is more bluntly pointed, and the shell color is more yellow.

Range length: 12.7 (high) cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

Nature serve conservation status ⁸

Rounded Global Status Rank: G5 - Secure

Reasons: This species is widespread in the eastern U.S., occurring throughout much of the Mississippi River system, and portions of the Great Lakes drainage and can often be abundant at given sites.

Range description ⁹

This species is widespread in the eastern U.S.A., occurring throughout much of the Mississippi River system, and portions of the Great Lakes drainage (Mirarchi et al. 2004). Its distribution includes the entire Mississippi River drainage from the St. Lawrence River and its tributaries south to northern Louisiana and west to the tributaries of the Red River, Oklahoma (Parmalee and Bogan 1998). In Canada, it is common in the Great Lakes and their tributaries from Lake Michigan to Lake Erie, and uncommon in Lake Ontario and the St. Lawrence River (Clarke 1981).

Sources and Credits

1. (c) Tim Lane, some rights reserved (CC BY-NC-ND), http://www.flickr.com/photos/119210184@N05/12941172094/
2. (c) Rob Curtis, some rights reserved (CC BY-NC-SA), uploaded by Rob Curtis
3. (c) Tomás Curtis, some rights reserved (CC BY-NC), uploaded by Tomás Curtis
4. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28851380
5. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28851386
6. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34440680
7. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31392489
8. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28851374
9. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34440681

More Info

• iNat taxon page
• Animal Diversity Web
• Biodiversity Heritage Library
• BOLD Systems BIN search
• Global Biodiversity Information Facility (GBIF)
• SeaLifeBase
• World Register of Marine Species

Range Map

(c) NatureServe, some rights reserved (CC-BY-NC)

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