Macrobdella decora

Macrobdella decora
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Annelida
Clade:	Pleistoannelida
Clade:	Sedentaria
Class:	Clitellata
Subclass:	Hirudinea
Order:	Arhynchobdellida
Family:	Macrobdellidae
Genus:	Macrobdella
Species:	M. decora
Binomial name
Macrobdella decora (Say, 1824)
Observed
Synonyms[1]
Hirudo decora Say, 1824

Macrobdella decora, also known as the North American medicinal leech, is a species of freshwater leech found in much of eastern North America in freshwater habitats. M. decora is a parasite of vertebrates, including humans, and an aquatic predator of eggs, larvae, and other invertebrates. It is a medium-sized leech with a spotted greenish-brown back and a dull orange underbelly. It has ten ocelli, or simple eyes, arranged in a horseshoe shape, as well as three long jaws. Internally, a pharynx takes up a tenth of its digestive tract; a stomach, the majority of its body length. The stomach connects to an intestine, followed by a colon, a rectum, and finally an anus located on the leech's back. M. decora, like all leeches, is hermaphroditic, and has ten testisacs and two ovisacs, in addition to male and female genital pores. First described by Thomas Say in 1824, the species is now placed in the genus Macrobdella. Its closest relative is believed to be the species Macrobdella diplotertia.

Macrobdella decora is found in North America east of the Rocky mountains: in southern Canada and the neighbouring parts of the United States. There is, however, one disjunct population of leeches living in northern Mexico. The species may be panmictic across most of its range, but the question remains unanswered and further research into the topic is needed. It is not considered to be endangered. The saliva of M. decora contains a blood thinner dubbed "decorsin" which may be unique to the species. A comparison of the saliva of M. decora and that of European species has lead researchers to the conclusion that blood-sucking in jawed leeches likely evolved from a single origin.