Nebraska Academy of Sciences


Date of this Version



Published in 2002. Transactions of the Nebraska Academy of Sciences 28: 21-27; Copyright © 2002 Willis


freshwater fish, was originally described as having distinct lobate testes, and subsequent descriptions have left this original description unchanged. The present study quantifies the observation of distinctly non-lobate testes that could be categorized as round or asymmetrical in addition to the previously described lobate testes. Six hundred thirty six A. lobatum were collected from 228 Semotilus atromaculatus over a 9 month period. Overall, 21.3%, 61.6%, and 16% were found to be round, asymmetrical, and lobate testes respectively (N = 1071). Analysis of testis morphology found the increasing presence of lobate testis as the length of A. lobatum increased, being the prominent morph in parasites > 40 mm. Analysis of previous studies in Nebraska and Idaho, USA, confirm the presence of all three testicular categories, with a predominance of lobate testes in 9 of the 12 studies. Complete morphological analyses of A. lobatum over this study period are reported and demonstrate greater variation than did previous studies

Included in

Life Sciences Commons