Several species are known in the Southwest. Vertebral characters that could allow assignment to species are unknown (Parmley 1990). Occurrence in many habitats at most elevations was noted by Van Devender and Worthington (1977).
Fig. 1. Plains Blackhead Snake. Photograph by Carl S. Lieb.
Mid Wisconsin: Rancho La Brea (LaDuke 1991).
Late Wisconsin/Holocene: Fowlkes Cave (Parmley 1990); Howell's Ridge Cave (Van Devender and Worthington 1977).
Literature. LaDuke 1991; Parmley 1990; Van Devender and Worthington 1977.
This small snake is widespread today throughout the Southwest and northern Mexico.
Late Wisconsin: Picacho Peak (Van Devender et al. 1991: cf.)
Literature. Van Devender et al. 1991.
Last Update: 1 Dec 2013