| Haementeria ghilianii | |
|---|---|
| |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Class: | Clitellata |
| Subclass: | Hirudinea |
| Order: | Rhynchobdellida |
| Family: | Glossiphoniidae |
| Genus: | Haementeria |
| Species: | H. ghilianii
|
| Binomial name | |
| Haementeria ghilianii de Filippi, 1849
| |
Haementeria ghilianii, (the Amazon giant leech) is one of the world's largest species of leeches.
Haementeria ghilianii is a species of leech in the Glossiphoniidae family, comprised of 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.[1]
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.[1] Following Grandma Moses' death, the specimen was placed in the Smithsonian's National Invertebrate Collection.[2]
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.[1] This makes it the largest freshwater leech known.[2] 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.[1][2] 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.[3]
This species is hermaphroditic; the male reproductive system is 3 g (0.0066 lb) to 5 g (0.011 lb) while the female reproductive system is 10 g (0.022 lb).[2][1] 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.[4]
When stressed, leeches will produce mucus to evade predators.[3]
Unlike jawed leeches who use rows of teeth to puncture skin, Haementeria ghilianii uses a 10 centimetres (3.9 in) 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.[1][5] Blood is moved into the digestive system through a series of undulation movements, and leeches can go months without feeding.[3][5] Observed host species include humans, rabbits, and cows.[1][5] Claims from 1899 state that leeches could aggregate to the point of killing birds and cattle.[3]
Haementeria ghilianii is endemic to the northern portions of the Amazon river, ranging from Venezuela and the Guianas.[1]