New Parasitic Isopod Species Discovered by ZSI in Bay of Bengal
Kolkata, March 25, 2025: A novel species of parasitic isopod, designated Lobothorax bharat, has been identified in the Bay of Bengal by researchers from the Zoological Survey of India (ZSI). This discovery, a result of collaborative research between the Estuarine Biology Regional Centre, Zoological Survey of India (ZSI), Gopalpur-on-Sea, and Berhampur University, contributes significantly to the existing knowledge of marine biodiversity and fish parasitology. The research team from ZSI comprised Sandeep Kumar Mohapatra, Sanmitra Roy, Dr. Jaya Kishore Seth, Dr. Basudev Tripathy, and Dr. Anil Mohapatra. The research was conducted under the joint leadership of Dr. Jaya Kishore Seth, Dr. Anil Mohapatra and Dr. Basudev Tripathy.
The newly identified species, Lobothorax bharat Mohapatra, Roy, Seth, Tripathy, and Mohapatra, 2025, belongs to the genus Lobothorax, a group of isopods known to parasitize the buccal cavity of marine fish. These parasites survive by feeding on the blood and mucus of their hosts, often leading to anaemia in affected fish populations.
Six specimens of L. bharat were collected from the mouths of the ribbonfish, Trichiurus lepturus Linnaeus 1758, at the Bahabalpur fish landing centre in Balasore district and the Gopalpur fish landing centre in Ganjam district, Odisha. The isopod, approximately 3 cm in length and creamy white in color, is characterized by seven pereonites and five pleonites. It employs seven pairs of legs, each equipped with hook-shaped dactyli, to firmly attach itself to the fish’s oral cavity.
“This discovery is significant because it not only adds to the known diversity of Lobothorax isopods but also highlights the complex ecological relationships within the Bay of Bengal,” stated Dr. Dhriti Banerjee, Director, ZSI.
Lobothorax bharat is distinguished from its closest relative, Lobothorax typus Bleeker, 1857, by several key morphological features, including:
● A distinct dorso-medial ridge on the pereon.
● The presence of three spines on the maxilliped.
● Smaller, spoon-like anterolateral processes on the first pereonite.
● A sub-truncated anterolateral margin of the cephalon.
Furthermore, genetic analysis revealed a 2.5% divergence in the mitochondrial cytochrome c oxidase subunit I (COI) gene sequence between L. bharat and L. typus, confirming its status as a distinct species.
Prior to this discovery, the genus Lobothorax comprised only three known species. The addition of L. bharat brings the total number to four, underscoring the ongoing need for comprehensive marine biodiversity research.
The research, which began in 2023, emphasizes the importance of continued exploration and study of marine ecosystems to uncover and understand the intricate lives of marine organisms.
