Aspects of the morphology and life history of Oculotrema hippopotami (Polystomatidae: Monogenea)
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Date
1999-01
Authors
Moeng, Itumeleng Amos
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Free State
Abstract
Being the only monogenean known from a warm-blooded animal and from a mammal
Oculotrema hippopotami Stunkard (1924) took a major leap in monogenean evolution.
After its description in 1924 various researchers rejected the claim that it came from the
hippopotamus and made it out as a mislabeled specimen. It was only 40 years later that
this parasite received full recognition. In spite of the fact that it was described more than
seven decades ago, only a few papers on this parasite have seen the light. During 1996
this parasite was rediscovered in South Africa. A hippopotamus culling program in
Kwazulu-Natal gave an opportunity to study this parasite.
The present study is the first detailed attempt to study the morphology and life history of
Oculotrema hippopotami. The approach in this study was as follows:
1. Background on the host's morphology, behaviour and phylogeny is given. The
hippopotamus' eye is situated deep in the orbit with the result that a deep crevice
is present all around the eye, which serves as habitat for the parasites.
2. The external morphology of the egg, oncomiracidium and adult parasite was
studied USIng scannmg electron rrucroscopy. This is the first ever scanrung
electron microscopical study of 0. hippopotami and this study revealed many new
information.
3. The internal morphology of the adult parasite was studied histologically using
wax sections. This revealed unique musculature in the mid piece that has never
before been reported for any polystomatid parasite.
4. Sperm morphology and the ultrastructure of the musculature in the mid piece was
studied at transmission electron mieroeope level. Indications are that the sperm
morphology is very similar to that reported for other polystomatids.
5. Infection levels for different seasons were compared. In contrast with most other
polystomatids that reproduce during the warmer summer months, 0. hippopotami
lays eggs during the cooler winter months.
6. The parental care and behaviour of a pair of hippopotami with a newborn calf
were studied. A very close bond with long periods of physical contact was
observed. This could give an ideal opportunity for parasite transmission from
mother to calf.
Description
Keywords
Hippopotamus -- South Africa -- KwaZulu-Natal -- Parasites, Monogenea -- Morphology, Host-parasite relationships, Dissertation (M.Sc. (Zoology and Entomology) )--University of the Free State, 1999