It’s not every day that you come across a living member of an extinct species. Nathan Whelan, a doctoral student at the University of Alabama, had such a day in 2011, when he found specimens of Leptoxis compacta on the banks of the Cahaba River. The last recorded collection of L. compacta more commonly known as the oblong rocksnail, dates back to 1933; the species was formally declared extinct in 2000. The first picture above is Figure 4 from the manuscript, published just last month.
Whelan et al. conducted several tests to confirm that this species above was indeed L. compacta. They compared the shells they found with shells of other known gastropods in the same area. The shells were dissimilar in both pigmentation and pattern. The researchers also compared their findings with archival L. compacta. By using a scanning electron microscope (SEM), they found strong evidence to suggest that they had rediscovered a heretofore “extinct” species.
Citation: Whelan NV, Johnson PD, Harris PM (2012) Rediscovery of Leptoxis compacta (Anthony, 1854) (Gastropoda: Cerithioidea: Pleuroceridae). PLoS ONE 7(8): e42499. doi:10.1371/journal.pone.0042499