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Acta Parasitologica

, Volume 64, Issue 1, pp 138–147 | Cite as

Muscular Arrangement and Sclerite Morphology in the Haptor of Tetraonchus monenteron (Monogenea, Dactylogyridea)

  • Anatoly A. PetrovEmail author
  • Pavel I. Gerasev
Original Paper
  • 27 Downloads

Abstract

Background 

Tetraonchidae is a small and relatively monomorphic family of dactylogyroid monogeneans. Since the morphology of sclerites of the attachment organ (haptor) is one of the primary criteria in tetraonchid taxonomy, the confocal study of sclerites and associated musculature may provide valuable taxonomic information.

Purpose 

The aim of this study was to examine the haptoral sclerites and musculature in Tetraonchus monenteron (Wagener, 1857), a common parasite of pike.

Methods

Haptoral musculature of T. monenteron was studied using phalloidin staining and confocal microscopy, with sclerites visualized in the reflection confocal mode.

Results

Haptoral armature of T. monenteron consists of ventral and dorsal pairs of anchors, a ventral bar, eight pairs of marginal hooks and at least three pairs of accessory sclerites. Anchors are operated by 14 muscles, of which the most prominent are extrinsic muscles, the transverse muscle interconnecting the ventral anchors, three muscles connecting the ventral anchor to the ventral bar, and four muscles of the dorsal and ventral anchors inserting on the haptoral wall. The extrinsic muscles are attached to the braceshaped sclerites, which in turn are connected to the dorsal anchors via muscle bundles.

Conclusion

The gaffing action of the dorsal anchors is likely to be achieved by the extrinsic muscles and the transverse muscle that clamps the extrinsic muscles against the body wall. The ventral anchors are probably held in attached position by the transverse muscle and four muscles inserting on the ventral bar and haptoral wall. The haptoral musculature may have potential utility for tetraonchid taxonomy.

Keywords

Tetraonchus Haptor Muscles Sclerites Confocal microscopy Phalloidin 

Abbreviations

ar

Anterior ridge of the ventral bar

bas

Ball-shaped sclerite

bd

Blade of the dorsal anchor

brm

Muscle bundles of the brace-shaped sclerites

brs

Brace-shaped sclerite

bv

Blade of the ventral anchor

cb

Central bridge of the ventral bar

da

Dorsal anchor

daf1-2

Muscles connecting the dorsal anchor to flabellate sclerite

daw1-2

Muscles connecting the dorsal anchor to the body wall

de

Dorsal branch of the extrinsic muscles

div1-2

Muscles connecting the ipsilateral dorsal and ventral anchors

dov

Muscle connecting the opposite dorsal and ventral anchors

ex

Extrinsic muscles

fl

Filament loop

flm

Muscle of the filament loop

fs

Flabellate sclerite

h

Haptor

id

Inner root of the dorsal anchor

ld

Fibrous loop of the dorsal anchor

le1-3

Lateral branches of the extrinsic muscles

lv

Fibrous loop of the ventral anchor

mb

Blade of the marginal hook

mh

Marginal hook

mp

Protractor muscle of the marginal hook

mr

Medial ridge

ms

Shaft of the marginal hook

ov

Outer root of the ventral anchor

pe

Posterior endings of the extrinsic muscles

ph

Pharynx

rid

Ridge on the inner root of the dorsal anchor

riv

Ridge on the inner root of the ventral anchor

rod

Ridge on the outer root of the dorsal anchor

rov

Ridge on the outer root of the ventral anchor

rpm

Retractor muscle of the hook-bearing papilla

th

Thumb of sickle

thm

Thumb muscle

tid

Tip of the inner root of the dorsal anchor

tiv

Tip of the inner root of the ventral anchor

tod

Tip of the outer root of the dorsal anchor

tov

Tip of the outer root of the ventral anchor

va

Ventral anchor

vat

Transverse muscle of the ventral anchors

vav1-3

Muscles connecting the ventral anchor and the ventral bar

vaw

Muscle connecting the ventral anchor to the body wall

vb

Ventral bar

Notes

Acknowledgements

This work was supported by budget funding of the Russian Academy of Sciences (projects AAAA-A17-117030110029-3 and AAAA-A17-117030310322-3). Confocal microscopy was performed at the “Taxon” Research Resource Centre (Zoological Institute RAS) (http://www.ckp-rf.ru/ckp/3038/).

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Copyright information

© Witold Stefański Institute of Parasitology, Polish Academy of Sciences 2019

Authors and Affiliations

  1. 1.Zoological Institute of the Russian Academy of SciencesSaint PetersburgRussia

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