Illinois Natural History Survey - University of Illinois

Pleurobema rubrum (Rafinesque, 1820)

Pyramid pigtoe


Pleurobema rubrum, INHS 3122
Pleurobema rubrum, INHS 3122. Little Wabash River, Wayne County, Illinois.
Length: 2.4 inches (6.1 cm).

Other common names Pink pigtoe.

Key characters Triangular and elongate shell, shallow sulcus present, rose-colored nacre, moderately deep beak cavity.


Similar species All other pigtoes (Fusconaia and Pleurobema).

Description Shell thick, triangular and elongate, and moderately inflated. Anterior end rounded, posterior end rounded to bluntly pointed. Dorsal and ventral margins curved. Umbos high, projected forward, and anterior to rest of shell. Shell smooth or satin-like. Shallow sulcus present. Periostracum brown or chestnut, with faint green rays on the umbos. Length to 4 inches (10.2 cm).

Pseudocardinal teeth well developed; two in the left valve, one in the right. Lateral teeth straight or slightly curved. Beak cavity moderately deep. Nacre pink or rose-colored in most individuals, occasionally white.Pleurobema rubrum distribution

Habitat Medium to large rivers in sand or gravel in areas with a good current.

Status Widespread but rare in the Ohio River drainage. Federal Candidate (Category 2). Endangered in Indiana and Ohio. Species of Special Concern in Illinois.

Back Forward Species | Table of Contents

Illinois Natural History Survey

1816 South Oak Street, MC 652
Champaign, IL 61820

Terms of use. Email the Web Administrator with questions or comments.

© 2019 University of Illinois Board of Trustees. All rights reserved.
For permissions information, contact the Illinois Natural History Survey.

Staff Intranet