The haptor is the attachment organ of the
monogeneans, a group of
parasiticPlatyhelminthes.
The haptor is sometimes called opisthaptor (from opistho-: behind) to emphasize that it is located in the posterior part of the body, and to differentiate it from the prohaptor (from pro-: in front), a structure including glands located at the anterior part of the body.
According to
Yamaguti (1963),[3] the chief adhesive organ of the monogeneans, the haptor, is posterior, more or less discoid, muscular, may be divided into alveoli or loculi, is usually provided with anchors, has nearly always marginal larval hooklets, or is in a reduced form with anchors. The haptor may consist of symmetrical or asymmetrical, sessile or pedunculate, muscular
suckers or
clamps with or without supporting
sclerites; accessory adhesive organs may be present in form of armed plaques, lappets or appendices.
The structure of the haptor is different in the two major groups constituting the
Monogenea, namely the
Polyopisthocotylea and the
Monopisthocotylea, and is an important part of the diagnosis in both groups.
In the Polyopisthocotylea, the haptor usually bears several clamps or suckers, and is often asymmetrical.[4]
In the Monopisthocotylea, the haptor comprises a single, symmetrical attachment unit, and has never haptoral clamps.[5] In the family
Diplectanidae, the haptor bears special structures (one ventral and one dorsal) called
squamodiscs or
lamellodiscs.
^Yamaguti, S. (1963). Systema Helminthum Volume IV Monogenea and Aspidocotylea. Interscience, a division of John Wiley & Sons, New York & London. 699 pages; definition of haptor, page 3.
^Hayward, C. (2005). Monogenea Polyopisthocotylea (ectoparasitic flukes). In K. Rohde (Ed.), Marine Parasitology (pp. 55-63): CSIRO, Collingwood, Australia & CABI, Oxon, UK.
^Whittington, I. D. (2005). Monogenea Monopisthocotylea (ectoparasitic flukes). In K. Rohde (Ed.), Marine Parasitology (pp. 63-72): CSIRO, Collingwood, Australia & CABI, Oxon, UK.