Stenotrema nudum (Pilsbry, 1900) Nude Slitmouth

    Drift, Paint Rock River system, Estill Fork, 1 mi N. Estillfork, Jackson County, Alabama, Bob Winters! 2/20/2017 (10.6 mm.). The apertural view of shells from this uniform sample resemble the specimen identified as S. stenotrema nudum from Belleview, Lincoln Co., S. central Tenessee by Pilsbry (1940: 658, figs. f). Aside from the reduction of the periostracal processes, Pilsbry cited the high parietal tooth leaning "strongly towards the basal lip.... tooth between notch and interdenticular sinus strongly developed, being higher and stronger than in stenotrema proper. Periphery very indistinctly subangular." Years after his description of this taxon as a subspecies, Pilsbry (loc. cit.) expressed doubt as to its genetic isolation. However, drift samples contain substantial numbers of both S. s. and S. nudum without intergradation.