Haementeria ghilianii

Haementeria ghilianii, commonly known as the Amazon giant leech, is one of the world's largest species of leeches.

Taxonomy and discovery
Haementeria ghilianii is a species of leech in the Glossiphoniidae family, comprising freshwater proboscis-bearing leeches. Colloquially, they are known as the Amazon giant leech. The species was declared extinct in 1893 after no wild specimen could be found.

Rediscovery and colonization
In the 1970s, Dr. Roy Sawyer discovered two adult specimens in a pond located in French Guiana. One of these leeches, dubbed Grandma Moses, founded a successful breeding colony at UC Berkeley. This specimen produced 750 offspring. Following Grandma Moses' death, the specimen was placed in the Smithsonian's National Invertebrate Collection.

Description
Haementeria ghilianii is a jawless, blood sucking leech. It can grow to 450 mm (17.7 in) in length and 100 mm (3.9 in) in width. This makes it the largest freshwater leech known. As adults, these leeches are a uniform greyish-brown color. Juveniles do not have a uniform color, but rather, a noncontinuous greyish-brown stripe and patches of color. The leeches form a "cobra hood" like shape that is widest in the center but tapers off on both ends. The wider end is where the proboscis is located, while the head is at the narrow end; H. ghilianii is made up 34 segments, each with its own ganglia.

Life cycle
This species is hermaphroditic; the male reproductive system is 3 g to 5 g while the female reproductive system is 10 g. Growth is irregular, as the leech's body weight increases by 3 to 6 fold times per feeding. Fecundity is based upon the weight of the leech during oviposition; egg clutches range from 60 to 500 eggs.

Behavior and ecology
When stressed, leeches will produce mucus to evade predators.

Feeding
Unlike jawed leeches who use rows of teeth to puncture skin, Haementeria ghilianii uses a 10 cm hypodermic needle style proboscis to feed. Bites are kept open by the fibrinogenolytic (breaks up fibrinogen) enzyme hementin, which is secreted from the proboscis' lumen; secretion is neurologically controlled. Hementin dissolves clots within the proboscis by breaking up the fibrinogen links between individual platelets. Once attached to a host, they release anticoagulants to prevent clotting, consuming blood at a rate of 0.14 ml to 15 ml per minute. Blood is moved into the digestive system through a series of undulation movements, and leeches can go months without feeding. Observed host species include humans, rabbits, and cows. Claims from 1899 state that leeches could aggregate to the point of killing birds and cattle.

Distribution
Haementeria ghilianii is endemic to the northern portions of the Amazon river, ranging from Venezuela and the Guianas.