|Abstract or Summary
- Seven species of fresh water fishes belonging to three different
families and two species of snails from Ritner Creek, Polk County,
Oregon were surveyed for adult and larval trematodes. A total of
seven species of trematodes representing four families was recovered
from the intestine of the fishes. Of these, at least two were under
scribed new species. The trematodes were described and their
The stream snails, Oxytrema silicula and Flumenicola virens,
were found to harbor at least 17 apparent species of larval trematodes.
Five of these were described from the snails for the first time. A
check-list of cercariae known to infect O. silicula and F. virens in the
Pacific Northwest was presented.
Life histories of five of the trematodes .encountered during the
surveys were studied. The experimental life cycle of Apophallus
donicus Skrjabin and Lindtrop, 1919 was completed. The cercaria, of
the pleurolophocercous group, was found in F. virens, while the metacercaria
encysted in a number of fresh water fishes. The life cycle of
Plagioporus siliculus Sinitsin, 1931 was demonstrated for the first
time. The cotylomicrocercous cercaria developed in sporocyst in
O. silicula and penetrated crayfish, Pacifastacus lenuisculus to encyst
in the abdominal muscles. The experimental definitive host used was
the rainbow trout.
A single adult Echinochasmus milvi Yamaguti, 1939 was
recovered from a duck fed echinostome cysts found naturally in the
gills of blackside dace, Rhinichthys osculus nubilus and redside
shiner, Richardsoni balteatus hydrophlox. This constituted the third
record of the trematode in the Pacific Northwest. The cercaria of
E. milvi was believed to be Cercaria gorgonocephala Ward, 1916,
which Martin (1968) redescribed from O. silicula. Two other macrocercous
cercariae--one aggregating but albino while the other nonaggregating--
were also found in O. silicula, The body of these
cercariae was identical to that of C. gorgonocephala. The taxonomic
relation of the three cercariae was discussed.
The partial life cycle of a new monorchiid trematode from the
torrent sculpin, Cottus rhotheus, was presented. The natural secondary intermediate host was found to be lampreys, both brook (Lampetra
richardsoni) and Pacific (L. tridentata). The first intermediate host
is still unknown. The partial life cycle of another new trematode, an Echinochasmus
sp., was also reported. The adult was obtained from a duck
experimentally fed small cysts in the gills of blackside dace. The
first intermediate host is unknown.