New Catfish Species: Exostoma sentiyonoae

A newly discovered catfish species, Exostoma sentiyonoae, has been identified in the Dzuleke River, Nagaland, India. This river forms part of the Barak River system, and the discovery highlights the rich aquatic biodiversity of the region.

Discovery Publication

The findings were published in the journal Zootaxa by two researchers:

• Bungdon Shangningam from the Zoological Survey of India
• Limatemjen from Kohima Science College

The holotype of the species is cataloged as ZSI FF 9871, with the specimen measuring 75.8 mm in length.

Key Features of Exostoma sentiyonoae

Exostoma sentiyonoae possesses distinct characteristics that set it apart from other species in the same genus. Notable features include:

• An adipose fin connected to the upper caudal-fin rays
• Presence of tubercles (small bumps) on the dorsal fin spine
• A slender head structure
• A significant gap between the dorsal fin and the adipose fin
• Small eyes and a total of 41 vertebrae

Taxonomic Distinctions

Comparative analysis revealed how Exostoma sentiyonoae differs from related species:

• Versus E. berdmorei: It has a shorter dorsal-fin base, a longer gap between the dorsal and adipose fins, and smaller eyes.
• Versus E. gaoligongense: It has a shorter gap between the pectoral and pelvic fins and smaller eyes.
• Versus E. effreni: Found in the Chao Phraya River, this species has a narrower head and shallower caudal peduncle compared to Exostoma sentiyonoae.
• Versus E. peregrinator: It exhibits a longer gap between the dorsal and adipose fins and a shorter anal-fin base.

This is the first time a species of the genus Exostoma has been documented in the Dzuleke River. The discovery emphasizes the potential for finding more undiscovered species in the region, given the challenging terrain and the limited exploration of local fish species.

Future Research Needs

The researchers underscore the importance of continued study of Nagaland’s rivers and recommend:

• Expanding surveys to discover other fish species, including conducting genetic studies
• Investigating species distribution and ecological interactions
• Developing conservation strategies to protect the unique aquatic biodiversity of the region

The identification of Exostoma sentiyonoae is a significant contribution to understanding the fish diversity in Nagaland and supports broader conservation efforts in biodiversity hotspots like the Eastern Himalayas and Indo-Burma. Further research will be crucial in uncovering more hidden species in these remote, ecologically rich areas.