ZOO 115 Invertebrate Zoology Phylum Annelida Class Clitellata Subclass Hiruninoidea

Subclass Hiruninoidea- General Characteristics http://news.nationalgeographic.com/kids/2003/10/images/leech-big.jpg ~ 350 species Terrestrial, freshwater and Marine Ectoparasites or predators Leeches Range from 1 cm to 30 cm in size http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20Laboratory/Protostomes/protostomes.htm

Subclass Hiruninoidea- General Characteristics All have a terminal or posterior sucker No Chaetae

Subclass Hirundinomorpha - external anatomy Typically have an anterior sucker as well http://www.mathematik.uni-bielefeld.de/~alscher/anatomy.html

Subclass Hiruninoidea- locomotion http://biodidac.bio.uottawa.ca/thumbnails/images/HIRU001B.gif http://bio.classes.ucsc.edu/bio136/annelids/hirudinea/hirudinea1.gif Musculature Longitudinal Diagonal Circular Dorso-ventral

Subclass Hiruninoidea- Nervous system Similar to Oligochaetes Anterior and Posterior Ganglia more concentrated because of suckers Have sensory papilla along body Small projecting discs containing many sensory cells Chemosensory Vibration Heat

Subclass Hiruninoidea- Feeding and Digestion Mouth usually in anterior sucker Jaws cut flesh Salivary glands secrete Hirudin Most have jaws Muscular Pharynx http://animaldiversity.ummz.umich.edu/site/resources/Grzimek_inverts/Hirudinea/v02_id297_con_hiranat.jpg/view.html Salivary glands

Subclass Hiruninoidea- Feeding and Digestion Gastric cecum -note that it has been disconnected from the pharynx and moved to show other parts of the anatomy Blood or prey sucked in with pharynx Blood meal up 10x body weight Passed to simple gastric cecum Bacteria do most of the digestion http://animaldiversity.ummz.umich.edu/site/resources/Grzimek_inverts/Hirudinea/v02_id297_con_hiranat.jpg/view.html

Subclass Hiruninoidea- Feeding and Digestion Anus is dorsal and anterior to the posterior sucker

Subclass Hiruninoidea- Circulatory system Simple system reverting back to sinuses Coelom is a global circulatory system

Subclass Hiruninoidea- Excretion Metanephridia Usually one pair per segment

Subclass Hiruninoidea- Respiration Mostly by diffusion through the body wall A few species have gills

Subclass Hiruninoidea- Reproduction Prostate gland Penis in sheath Testis sacs in posterior of animal - not shown Ovary Vagina Sexual only Hermaphrodites However they are protandric Male then Female Copulation Annual or 2 yr cycle Many have a penis Others use hypodermic penetration

Subclass Hiruninoidea- Reproduction Prostate gland Penis in sheath Testis sacs in posterior of animal - not shown Ovary Vagina Clitellum used to develop cocoon for eggs Eggs laid from a few days to months after copulation Hatch 3-5 wks

Problems caused by leeches Gut bacteria can cause wound infection. In the post-operative use of leeches this is closely monitored and dealt with by use of the appropriate antibiotic. There is no evidence to suggest that leeches transmit diseases or parasites. The presence of trypanosomes, (malarial parasites), in the gut of jawless leeches has been noted, but jawed leeches do not appear to be hosts.

Problems caused by leeches In 1799, soldiers serving under Napoleon marched from Egypt across the Sinai Peninsula to Syria. They drank water from waters contaminated by leeches. Leeches attached to the insides of the soldiers noses, mouths, and throats. Once attached, the leeches gorged on blood and enlarged Many of the soldiers died from suffocation. In addition, other soldiers died from excessive blood loss.

Medicinal uses Plastic surgeons use them when venous congestion of skin and muscle flaps is a problem. Leeches are treated in the same way as blood products and are reused only on the same patient. Treatment of black eyes Hirudin treatment of inflammation of the middle ear being developed for experimental use as a systemic anticoagulant