Macrobdella sestertia Whitman, 1886:378

New England medicinal leech



Taxonomy & Nomenclature


Whitman (1886:378n): "This name [i.e. sestertia] is given in allusion to the fact that the sexual openings are separated by two and a half rings."


Conservation Status

Last record: 1886 or before (no date specified) (Whitman, 1886)

Rediscovered in 1976 (Smith, 1977)


It has been suggested that the species may be missing again (Carlson & Phillips, 2020).



Maine, Massachusetts (eastern), New Hampshire & South Carolina, USA

Type locality: "Charles River, Watertown, Mass." (Whitman, 1886:414)


Originally reported solely from Massachusetts (Whitman, 1886; Smith, 1977; Smith & Hanlon, 1997), the first new state record was Maine based upon a specimen collected on 12 July 1993 (Smith & Hanlon, 1997:232). Later in 2008, 9 specimens were collected in South Carolina for the first time (Poly, 2011, 2018). The species' known distribution was then expanded to New Hampshire based upon historical specimens that had previously been misidentified (Phillips et al., 2016).


Biology & Ecology

Smith (1977): "M. sestertia is apparently sanguinivorous in habits. Interviews with beach patrons indicate that large leeches often attack swimmers ..."









Original scientific description:

Whitman, C. O. (1886). The leeches of Japan. Part I. The ten-eyed leeches, or the Hirudinidae. Quarterly Journal of Microscopical Science (New Series, No. 103) 26(3): 317-416, pls. 17-21.


Other references:

Barnes, Robert D. (1987). Invertebrate Zoology. Fifth Edition. Saunders College Publishing, New York, New York. 893 pp.

Carlson, Colin J. and Phillips, Anna J. (2020). Is the New England medicinal leech (Macrobdella sestertia) extinct? Biological Conservation 243: 108495.

Holmes, Branden. (2021). What's Lost and What Remains: The Sixth Extinction in 100 Accounts (eBook). Self published.

Klemm, D. J. (1982). Leeches (Annelida: Hirudinea) of North America. U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio. EPA-600/3-82-025. 177pp.

NatureServe. (2015). NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available (Accessed: May 24, 2016).

Phillips, Anna J., Salas-Montiel, Ricardo, Kvist, Sebastian and Oceguera-Figueroa, Alejandro. (2019). Phylogenetic position and description of a new species of medicinal leech from the Eastern United States. Journal of Parasitology 105(4): 587-597.

Phillips, Anna J., Salas-Montiel, Ricardo and Oceguera-Figueroa, Alejandro. (2016). Distribution of the New England Medicinal Leech, Macrobdella sestertia Whitman, 1886 and redeterminations of specimens of Macrobdella (Annelida: Clitellata: Macrobdellidae) at the National Museum of Natural History, Smithsonian Institution. Proceedings of the Biological Society of Washington 129(1): 103-113.

Platt, John R. (2020, 29 May). A Lost Leech and a Call to Protect the Bloodsuckers. The Revelator (online). Available at: [Accessed on 22 February 2024]

Poly, William J. (2011). First record of the leech, Macrobdella sestertia (Annelida: Hirudinida), in South Carolina, pp. 142-145. In: Statewide Research – Freshwater Fisheries Annual Progress Report (2011, F–63), Division of Wildlife and Freshwater Fisheries, South Carolina Department of Natural Resources. i-ix + 1-159 pp.

Poly, William J. (2018). Range Extension for the Elusive New England Medicinal Leech, Macrobdella sestertia Whitman, 1886 (Hirudinida: Macrobdellidae), in South Carolina, U.S.A., with Notes on Morphology, Coloration, and Biology. Proceedings of the California Academy of Sciences, ser. 4, 64(12): 347-359, 8 figs.

Sawyer, R. T. (1972). North American freshwater leeches, exclusive of the Piscicolidae, with a key to all species. Illinois Biological Monographs 46. 154pp.

Smith, Douglas G. (1977). The rediscovery of Macrobdella sestertia Whitman (Hirudinea: Hirudinidae). Journal of Parasitology 63(4): 759-760.

Smith, Douglas G. and Hanlon, S. (1997). Macrobella sestertia (Hirudinea: Hirudinidae) in Maine and a key to the hirudiniform leeches of Maine. Northeastern Naturalist 4(4): 231-236.

Thorp, J. H. and Covich, A. P. (eds). (1991). Ecology and classification of North American freshwater invertebrates. Academic Press, Inc., Boston, MA. 911 pp.


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