Carlson, Colin J. and Phillips, Anna J. 2020. "Is the New England medicinal leech (Macrobdella sestertia) extinct?" Biological Conservation, 243 UNSP 108495–UNSP 108495. https://doi.org/10.1016/j.biocon.2020.108495.
Despite recent interest in invertebrate extinctions, most go undocumented due to chronic data deficiencies. Here, we investigate the absence of the New England medicinal leech (Macrobdella sestertia), a species not sighted in the last decade, but which has been rediscovered several times since it was described in 1886. We collate all known records (19 specimens from nine independent sightings) of this rare species, and use sighting-based extinction date estimators to evaluate the odds that populations of M. sestertia might persist. Using all available data and several different models, we find that while the species may be extinct, there is also not enough evidence to eliminate the hypothesis that the species remains extant. Given that the geographic range of M. sestertia is now known to extend much further south than previously thought, we recommend protections for M. sestertia should be expanded at state and potentially federal levels. We also recommend that systematists should continue to revisit Macrobdella records in natural history collections, which may turn up new evidence of its range, habitat preference, and possible persistence. We conclude by discussing implications of this work for the broader picture of leech conservation in Europe and North America.
