Genetic relatedness provides support for a species complex of myxosporeans infecting the Indian major carp, Labeo rohita

2015-11-27T09:37:26Z (GMT) by Harpreet Kaur Aditya Gupta
<p>Myxozoans are an economically important group of microscopic metazoan parasites of fish. The myxozoan species <em>Thelohanellus filli</em> infects commercially important freshwater fish both in wild and in cultured habitat. This parasite causes gill hemorrhagic disease and significant damage to the respiratory surface of the infected fish. In the present study, the 18S rDNA gene sequence of morphologically identified <em>T. filli</em> infecting the gill lamellae of the Indian major carp, <em>Labeo rohita</em>, was characterized. This revealed that we are actually dealing with a species complex containing <em>T. bifurcata</em>, <em>T. jiroveci</em> and <em>T. seni</em>. Phylogenetically, <em>T. filli</em> clustered with other myxozoan parasites, with the species most closely related to <em>T. filli</em> having 96 to 97% sequence similarity. The intraspecific variation demonstrated in this study points towards the importance of newer approaches to facilitate reassessment of taxa and detecting species complexes and cryptic species.</p>