title: Morphological characterization of testicular cells, spermatogenesis and formation of spermatophores in a fish ectoparasite Argulus bengalensis Ramakrishna, 1951 (Crustacea: Branchiura).
abstract: The present study has been carried out to describe the cell morphology of the developing male gametes in a fish ectoparasite, Argulus bengalensis Ramakrishna, 1951. With respect to cell volume and nucleoplasmic index, spermatogonia are the smallest and primary spermatocytes are the largest in this lineage. The spermatogonia and the differentiating spermatogenic cells are in separate niches and confined to different enclaves within each testicular lobe. Spermiogenesis occurs within the inner enclave of each testicular lobe. During this process the nucleus becomes streamlined; an acrosome is formed, axoneme is originated, and residual cytoplasm is discarded through the flagellum. The sperm cell morphology displays a general pattern comprising head, mid-piece, and a full length flagellum. In the axoneme 9+2 arrangement of the microtubule is conserved. In addition to the axoneme, some more singlet microtubules are found surrounding a fiber sheath and around one of the mitochondria adjacent to the axoneme. This arrangement indicates a close phylogenetic relationship with pentastomida. In the present study, structure and formation of spermatophore are described in this branchiuran parasite.
authors.affiliation: Fish Biology Research Unit, Department of Zoology, School of Life Sciences, Visva-Bharati, A Central University, Santiniketan 731235, West Bengal, India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: Department of Zoology, Maulana Azad College, 8 Rafi Ahmed Kidawi Road, Kolkata 700013, West Bengal, India.
authors.forename: Subha
authors.initials: S
authors.lastname: Manna
authors.affiliation: Fish Biology Research Unit, Department of Zoology, School of Life Sciences, Visva-Bharati, A Central University, Santiniketan 731235, West Bengal, India. Electronic address: sahaskvb@rediffmail.com.
authors.forename: Samar Kumar
authors.initials: SK
authors.lastname: Saha
mesh_terms: D000818:Animals; D033341:Arguloida / Q000166:cytology*; D048430:Cell Shape; D003593:Cytoplasm; D005407:Flagella; D005854:Germ Cells / Q000166:cytology; D008297:Male; D008870:Microtubules; D008928:Mitochondria; D013087:Spermatids / Q000166:cytology; D013091:Spermatogenesis / Q000502:physiology*; D013093:Spermatogonia / Q000166:cytology*; D013094:Spermatozoa / Q000166:cytology*; D013737:Testis / Q000166:cytology*
keywords: Argulus bengalensis; Branchiura; Fish ectoparasite; Spermatogenic cell; Spermatophore; Spermatozoa