Dall, W.H. 1908. Descriptions and figures of some land and fresh-water shells from Mexico, believed to be new. Proceedings of the United States National Museum 35: 177-182. Available electronically.

‘Simpson’ Dall, 1908. Proc. U.S. Nat. Mus. 35: 181, pl. 30, fig. 3.
Type(s): LECTOTYPE USNM_163156 (by R.I. Johnson, 1998: 435), Salinas R., Coahuila, Mexico.