Comparative Parasitology 68(2) 2001 - Peru State College
Comparative Parasitology 68(2) 2001 - Peru State College
Comparative Parasitology 68(2) 2001 - Peru State College
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Comp. Parasitol.<br />
<strong>68</strong>(2), <strong>2001</strong>, pp. 236-241<br />
Supplemental Diagnosis of Myxobolus gibbosus (Myxozoa), with a<br />
Taxonomic Review of Myxobolids from Lepomis gibbosus<br />
(Centrarchidae) in North America<br />
DAVID K. CONE<br />
Department of Biology, Saint Mary's University, Halifax, Nova Scotia, Canada B3H 3C3<br />
(e-mail: david.cone@stmarys.ca)<br />
ABSTRACT: Myxobolus gibbosus Herrick, 1941 (Myxosporea) is reported from the connective tissue of gills of<br />
Lepomis gibbosus (Centrarchidae) in Algonquin Park, Ontario, Canada. The new material (formalin-preserved)<br />
is used to supplement the original taxonomic diagnosis of nearly 60 yr ago. Spores are round to oval in valvular<br />
view, 11-14 jjim long and 10-11 jxm wide, with a distinctly blunt capsular region. The polar capsules are<br />
relatively large for the size of the spore, measuring 6-7 jxm long and 3.5-4.0 (Jim wide, and aligned almost<br />
parallel to each other. There are 8-12 loose filament coils lying up to 45° to the long axis of the capsule. The<br />
taxonomy of species of Myxobolus described or reported from L. gibbosus in North America is examined, and<br />
the following are considered to be valid taxa: Myxobolus dechtiari Cone and Anderson, 1977; M. gibbosus;<br />
Myxobolus magnasphcrus Cone and Anderson, 1977; Myxobolus osburni Herrick, 1936; Myxobolus paralintoni<br />
Li and Desser, 1985; and Myxobolus uvidiferus Cone and Anderson, 1977. <strong>Comparative</strong> photographs of spores<br />
accompany differential diagnoses of the 6 species. Myxobolus gibbosus Li and Desser, 1985, and Myxobolus Hi<br />
Desser, 1993, are junior synonyms of M. uvidiferus. Myxobolus lepomicus Li and Desser, 1985, is considered a<br />
species inquirendae, and the reports of Myxobolus cyprinicola Reuss, 1906, and Myxobolus poecilichthidis<br />
Fantham, Porter, and Richardson, 1939, from L. gibbosus are considered misidentifications.<br />
KEY WORDS: Myxobolus gibbosus, Myxosporea, redescription, differential diagnoses, pumpkinseed sunfish,<br />
Lepomis gibbosus, Centrarchidae, Algonquin Park, Canada.<br />
Myxobolus gibbosus Herrick, 1941 (Myxozoa)<br />
was described from connective tissue of the<br />
gill arch of pumpkinseed sunfish (Lepomis gibbosus<br />
(Linnaeus, 1758)) from the island region<br />
of western Lake Erie (Herrick, 1941). In subsequent<br />
surveys of myxosporean parasites of<br />
pumpkinseed (Cone and Anderson, 1977a, b; Li<br />
and Desser, 1985; Hayden and Rogers, 1997),<br />
the parasite was not encountered. However, during<br />
a new survey of myxosporeans of fish in<br />
Algonquin Park, a single pseudocyst of M. gibbosus<br />
was discovered. This rare find enabled the<br />
author to assess information provided in the<br />
original species description and to critically<br />
compare the parasite with other species of the<br />
genus reported from pumpkinseed. The present<br />
study describes the new material and reviews the<br />
taxonomy of myxobolids from pumpkinseed in<br />
North America.<br />
Materials and Methods<br />
Nine pumpkinseed (6-8.9 cm in total length) were<br />
collected in baited trapnets set 20 June 1994 and 21<br />
June 1995 in the shallows of Lake Sasajewan<br />
(45°35'N; 78°30'W), Algonquin Park, Ontario, Canada.<br />
The fish were pithed and necropsied. All body organs<br />
and tissues were examined microscopically for<br />
myxosporean pseudocysts, and, when found, they were<br />
236<br />
fixed in 10% buffered formalin. Fixed pseudocysts<br />
were punctured and the spore contents stabilized in<br />
temporary mounts prepared with 1% agar (Lom,<br />
1969). Spores were photographed with interference<br />
contrast optics. Enlarged photographic prints of individual<br />
spores were used to determine spore dimensions.<br />
Descriptive terminology follows Lom and Dykova<br />
(1992). Measurements are presented in micrometers.<br />
The sample of M. gibbosus was compared with<br />
other species of Myxobolus in the author's collection,<br />
namely Myxobolus dechtiari Cone and Anderson,<br />
1977; Myxobolus magnaspherus Cone and Anderson,<br />
1977; Myxobolus osburni Herrick, 1936; Myxobolus<br />
paralintoni Li and Desser, 1985; and Myxobolus uvitliferus<br />
Cone and Anderson, 1977. Syntype slides of M.<br />
gibbosus (NMCICP 1984-0359), Myxobolus lepomicus<br />
(NMCICP 1984-0362), and M. paralintoni (NMCICP<br />
1984-0364) housed in the parasite collection of the Canadian<br />
Museum of Nature were also examined. A photo-voucher<br />
(negative film) is deposited in the United<br />
<strong>State</strong>s National Parasite Collection (USNPC), Beltsville,<br />
Maryland, U.S.A.<br />
Results<br />
Myxobolus gibbosus Herrick, 1941<br />
(Figs. 1 and 2)<br />
Supplementary diagnosis<br />
Copyright © 2011, The Helminthological Society of Washington<br />
Pseudocyst egg-shaped, gray-white and minute<br />
(250 long), embedded in connective tissue<br />
surrounding base of gill arch. Spores round to