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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

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