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The morphology of Ismaila monstrosa Bergh (Copepoda)

The morphology of a rather rare parasitic copepod was
studied. Ismaila monstrosa Bergh, an endoparasitic copepod was
found in the nudibranch, Antiopella fusca, at Coos Bay, Oregon.
Many anatomical features were found, which were different from
previous descriptions. Males were described for the first time.
Young males lacked the gonadal lobes found on the dorsal sides of
adult males. Both sexes had similar mouthparts, differing only in
size. These mouthparts consisted, like those of Splanchnotrophus,
of a bifid labrum, a pair of simple mandibles, a pair of maxillae
and a triangular labium with side processes. There was only a
single pair of maxillae and they are unusual in that they were
found to be setigerous and two-jointed. The distal portion of this
characteristic maxilla was biramous, the smaller member often
obscure. Because of this and other anatomical factors, I proposed
a new variety Ismaila monstrosa var. pacifica and a new subfamily,
the Ismailinae.
Although the female possessed three pairs of lateral appendages,
the male lacked these, having only the two pairs of ventral appendages.
In the female specimens there were two pairs of ventral appendages
or "stomach-arms". The first pair was bifurcate, the second pair
trifurcate. In the male specimens the first pair was uniramous and
the second pair unequally biramous.
The digestive system was found to be incomplete in both sexes.
There were no extensions into the "stomach-arms" No portions
of either nervous or circulatory systems were found in the sections.
The reproductive system was found to be the major one in
the body of the parasite. In the adults of both sexes the gonads
were in the dorsal and anterior gonadal lobes. The ovaries connected
to an extensively ramified oviduct. The lower part of the
oviduct connected to the anterior end of the cement glands. A
seminal receptacle was found in the female. In the male two testes
were seen in the dorsal gonadal lobes. The vas deferens ran into
the lower abdomen where spermatophores could be seen. / Graduation date: 1965
Date14 May 1965
CreatorsBelcik, Francis Peter
ContributorsPratt, Ivan
Source SetsOregon State University
Detected LanguageEnglish

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