Systematics and ecology of Gastrocopta (Gastrocopta) rogersensis (Gastropoda : Pupillidae), a new species of land snail from the midwest of the United States of America

Gastrocopta rogersensis, a new species of recent gastropod mollusk (Pupilli dae, Gastrocoptinae) is described from the vicinity of the Ozark Uplift and Paleozoic Plateau ("Driftless Area") in the midwestern USA, The structure of the angulo-parietal "tooth' in G. rogersensis, consists of two discrete subparallel lamellae borne on a rectangular callus, distinguishing it from all. Gastrocopta procera (Gould, 1840) subspecies and variants, including G astrocopta procera mcclungi (Hanna and Johnston, 1913), Gastrocoptaprorrra riparia (Pilsbry, 1912), and Gastrocopta procera sterkiana (Pilsbry, 1912). Morphometric analyses demonstrate that even at sites of co-occurrence, G. rogersensis shells are significantly (P<0.0005) smaller rence, G. rog than G. procera. Additionally, while G. rogersensis exhibits no variation in she ll size with latitude (P=0.876), a highly significant (P<0.0005) clinal var iation exists in G. procera. G. rogersensis populations appear restricted t o undisturbed calcareous bedrock outcrops in areas that escaped Wisconsinan glaciation. The limited range, habitat specificity, and potential fire sen sitivity of this species suggests that it should be given a high priority f or conservation.