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The attachment of the monogenean Diplectanum aequans (Wagener) Diesing to the gills of Morone labrax L.

Published online by Cambridge University Press:  06 April 2009

J. E. Paling
J. E. Paling
Affiliation:
Department of Zoology and Comparative Physiology, The University, Birmingham 15*
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Extract

The main adhesive apparatus of Diplectanum aequans is described and a functional interpretation is offered.

Two sets of organs are involved in adult animals: 4 hamuli (median hooks) and the 3 associated accessory bars, and 2 squamodiscs.

The two pairs of hamuli are ‘gaffed’ into the gill tissue of the host by the following mechanism: muscular contraction produces a posterior movement of the anterior ends of the hamuli which are so pivoted that the points of the hamuli are caused to extend out from the haptor.

The squamodiscs of adults are operated by extrinsic muscles which produce posterior movement in the anterior region of each squamodisc. This tends to push the parasite out from its position between adjacent secondary gill lamellae.

The tendency to dislodgement is opposed by the two pairs of hamuli which ‘gaff’ into the base of the secondary lamellae. In addition, the more posterior spines on the squamodiscs become embedded in the gill tissue and so provide further resistance to the movement of the anterior region of the squamodisc. Thus the attachment of adults requires both sets of adhesive organs functioning in a complementary manner.

Juveniles do not possess squamodiscs. They are considered to adhere to their hosts primarily with their hamuli.

I would like to acknowledge the help given to me by the Director and Staff of the Marine Biological Association Laboratory and also the Proprietors of Cook and Sons Ltd., of Salcombe, Devon.

Type
Research Article
Information
Parasitology , Volume 56 , Issue 3 , August 1966 , pp. 493 - 503
Copyright
Copyright © Cambridge University Press 1966

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References

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