Taxonomic Re-description and Molecular Characterization of Thelohanellus bifurcata Basu and Haldar, (1999) (Myxosporea: Myxobolidae) Using 18S rRNA Gene Sequences, Infecting the Gill Lamellae of Labeo rohita (Hamilton, 1822) from Ranaghat, West Bengal, India
Labani Halder
Department of Zoology, Diamond Harbour Women’s University, Sarisha, South 24- Parganas, West Bengal- 743368, India.
Lisa Basu
Department of Zoology, Diamond Harbour Women’s University, Sarisha, South 24- Parganas, West Bengal- 743368, India.
Chayanika Roy
Department of Zoology, Diamond Harbour Women’s University, Sarisha, South 24- Parganas, West Bengal- 743368, India.
Riya Mondal
Department of Zoology, Diamond Harbour Women’s University, Sarisha, South 24- Parganas, West Bengal- 743368, India.
Pafiza Parvin
Department of Zoology, Diamond Harbour Women’s University, Sarisha, South 24- Parganas, West Bengal- 743368, India.
Biplab Bhowmik
*
Department of Zoology, Diamond Harbour Women’s University, Sarisha, South 24- Parganas, West Bengal- 743368, India.
*Author to whom correspondence should be addressed.
Abstract
Myxozoans have been classified into 62 genera having more than 2600 species all over the world. Among these genus Thelohanellus Kudo, 1933 is the second largest genus after Myxobolus. During the survey of myxozoan parasites in fresh water fishes, the species Thelohanellus bifurcata Basu and Haldar, (1999) under genus Thelohanellus Kudo, 1933 was found to infect the gills of Indian major carp, Labeo rohita Hamilton, 1822 collected from Ranaghat fish markets (Latitude: 23.1793º N, Longitude: 88.5758º E), West Benagl, India. A total number of 67 fish were collected during the period of January, 2025 to October, 2025 and among them 6 fishes were found to be infected with the parasite. The rate of infection was 8.95%. The plasmodia were visible with naked eye and were large and elongated in shape. The present paper deals with the morphological re-description and molecular characterization of the parasite. The phylogenetic analysis was also done using the 18s rRNA gene sequences which justifies its taxonomic position and resolves the ambiguities regarding the species identification. This study also presents the molecular analysis of Thelohanellus bifurcata Basu and Haldar, (1999) for the second time from Indian sub-continent and for the first time from West Bengal.
Keywords: Myxozoa, Thelohanellus bifurcate, 18s rRNA, phylogeny, major carp, Labeo rohita