Discovery of Living Anguispira alternata (Say, 1816) (Discidae: Gastropoda) in Louisiana, USA

Of the 13 recognized species of Anguispira in the US, 2 are listed as occurring in Louisiana (NatureServe 2009). Anguispira alternata (Say, 1819) is a pulmonate land snail found throughout the eastern US, including states bordering the Mississippi River to the west (Hubricht 1985). The other species, A. strongylodes (Pfeiffer, 1854), is found across the southern US, with a range that narrowly overlaps A. alternata at its northern boundary. The shell of A. strongylodes differs from that of A. alternata by lacking streaks along the base and the umbilicus and by having smaller spots along the shell periphery (Pilsbry 1948). Hubricht (1985) listed only fossil A. alternata as occurring in Louisiana and Mississippi, while NatureServe (2009) lists it as extirpated in both states. Pilsbry viewed strongylodes as a weakly differentiated subspecies of A. alternata endemic to east-central Texas, although Hubricht (1960) later elevated strongylodes to species status and established its currently recognized range (Hubricht 1985).