Comparative Parasitology 68(2) 2001 - Peru State College

238 COMPARATIVE PARASITOLOGY, 68(2), JULY 2001
Table 1. Comparison of pertinent taxonomic information about Myxobolus gibbosus reported in the original
species description and that observed in the present study.
Host
Locality
Tissue site
Pseudocyst
Spore length
Spore width
Spore thickness
Polar capsule length
Polar capsule width
Polar filament coils
Herrick (1941)*
Lepomis gibbosus
Lake Erie
Connective tissue of gill
Round, 0.75 mm
10.6-12.3
9.8-12.3
6.5-8.2
5.7-7.4
3.3-4.1
8-12
* Based on fresh material in a hanging drop preparation.
t Based on formalin-fixed material in asar wet mounts.
to each other. It appears then that M. gibbosus
is simply rare in this region. The dimensions of
the preserved spores found in the present study
are similar to those described by Herrick (1941)
from fresh material (Table 1). It should be noted
that dimensions of fixed spores are often smaller
than those of fresh spores because shrinkage can
take place during fixation. This means that fresh
spores of M. gibbosus in Algonquin Park may
be slightly larger than those described originally
by Herrick (1941).
Spores of other species of Myxobolus (M. dechtiari,
M. magnaspherus, M. osburni, M. paralintoni,
and M. uvuliferus) from L. gibbosus are
presented for comparative purposes (Figs. 3—7).
Each species has a distinct spore shape and specific
tissue site in which it develops and is readily
identified by these indicators. Myxobolus
paralintoni (Fig. 4) has oval spores in frontal
view and develops in the bulbus arteriosus of the
heart (Hayden and Rogers, 1997; Cone and
Overstreet, 1998). Myxobolus dechtiari (Fig. 5)
has spores that are broadly pyriform in frontal
view and develops in gill tissue (Cone and Anderson,
1977a). Myxobolus uvuliferus has slightly
compressed spores in frontal view usually
with the width greater than length, often has polar
capsules dissimilar in the length, and develops
in the connective tissue capsule surrounding
the metacercaria of Uvulifer ambloplites
(Hughes, 1927) Dubois, 1938 (Cone and Anderson,
1977a). Myxobolus osburni has round
spores in frontal view and develops in the exocrine
tissue of the pancreas (Cone and Anderson,
1977a). Myxobolus magnaspherus has round
spores in frontal view that are huge, often 20
Copyright © 2011, The Helminthological Society of Washington
Present studyt
Lepomis gibbosus
Lake Sasajewan
Connective tissue of gill
Round, 0.25 mm
11-14
10-11
—
6-7
3.5-4
8-11
|xm in diameter, and develops in connective tissue
of the body, including the peritoneum (Cone
and Anderson, 1977a).
Taxonomic Key to the Species of Myxobolus
Infecting Pumpkinseed Sunfish
la. Spore length more than 16 jjim
M. magnaspherus (Fig. 8)
Ib. Spore length less than 16 |xm 2
2a. Polar capsules aligned more or less parallel -
M. gibbosus (Fig. 9)
2b. Polar capsules converged anteriorly 3
3a. Spore circular in frontal view M. osburni (Fig. 10)
3b. Spore not circular in frontal view 4
4a. Spore width greater than spore length
M. uvuliferus (Fig. 11)
4b. Spore width less than spore length 5
5a. Spore oval in frontal view M. paralintoni (Fig. 12)
5b. Spore broadly pyriform in frontal view
M. dechtiari (Fig. 13)
Discussion
Ten species of Myxobolus Butschli, 1882
(Myxosporea) have been reported from L. gibbosus
in North America (Herrick, 1936, 1941;
Cone and Anderson, 1977a, b; Ingram and
Mitchell, 1982; Li and Desser, 1985; Desser,
1993; Cone and Overstreet, 1998). The author
has necropsied L. gibbosus from Algonquin Park
and from Lake Erie and has to date encountered
6 of the 10 species, namely M. dechtiari, M.
gibbosus, M. magnaspherus, M. osburni, M.
paralintoni, and M. uvuliferus.
The reports of Myxobolus cyprinicola Reuss,
1906, and Myxobolus poecilichthidis Fantham,
Porter, and Richardson, 1939, from the brain and
heart and from the gills, respectively, of L. gib-