Sunday, August 14, 2011

Yabbie Parasite : Crayfish Parasite :Temnocephids / Temnocephalida / Flat Worm

Temnocephids / The Temnocephalida are an order of turbellarian flatworms, Platyhelminthes (flat worms).
Unlike most other turbellarians, all the species in this order are either commensal or parasitic. They can be found living on crustaceans, molluscs, and, in some species, even turtles. The commensal species typically live in the gill or mantle cavities of their hosts, while the parasites live inside the digestive system. Anatomically, temnocephalidans can be distinguished from related groups by the presence of an adhesive disc on the underside for attachment to the host, and of a number of finger-like projections arising from the head.

Taxonomic Checklist: 
Class: Order
Turbellaria: Tricladida
Temnocephalidea: Temnocephalida 

Distribution: Australia wide

Descriptive Features:
- body flat, thin or squat, bilaterally symmetrical
- absence of a coelom, anus, no distinct internal systems
- spaces between internal organs occupied by connective tissue
- Temnocephalidea with 2 – 6 tentacles posteriorly, suction disc anteriorly
- Total length: up to 20 mm

Temnocephids are an ectocommensal (external parasite) that reside on the exoskeleton of the yabbie (yabbie parasite).  They are often associated with low salinity and nutrient rich waters.  Eggs of  temnocephalids are laid on the underside of the tail of the yabbie and sometimes in their gill cavity.  Temnocephalids are rarely harmful to yabbies unless they are present in extremely high densities. Presence of adult temnocephalids or their eggs within the gill chamber of the yabbie may cause respiratory problems. Their appearance may also reduce the market appearance of the yabbie.  Adult Temnocephalids can easily be removed by washing the yabbies in a salt bath for a couple of minutes.  However the eggs of Temnocephalids/Temnocephalida are extremely adherent and remain even after steaming and boiling.

1 comment:

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