Fish species Moringua hodgarti rediscovered after a century in Arunachal Pradesh

Fishes of the family Synbranchidae, (swamp eels), are characterised by the absence of paired fins, unpaired fins rudimentary or absent, presence of an accessory breathing organ

A team of Indian researchers have rediscovered fish species Moringua hodgarti in Arunachal Pradesh’s Siang Valley after over a century. The records of the species was first collected during the Abor Expedition of 1911–1912 in Arunachal Pradesh.

The fish species measure around 177 mm to 211 mm and are commonly known as swamp eels. (HT sourced photo)

The discovery and analysis of the fish species measuring around 177 mm to 211 mm and commonly known as swamp eels has been published in the latest edition of Zootaxa, a peer-reviewed journal for animal taxonomists, published on Monday.

“We report the rediscovery of this species after 110 years, and provide a re-description based on freshly collected specimens... This species is known only from the Siang Valley in Arunachal Pradesh,” the team of researchers that comprised Nilanjan Mukherjee, Rahul G Kumar, Surya Narayanan and Aravind NA mentioned in the article, a copy of which HT has seen.

Fishes of the family Synbranchidae, (swamp eels), are characterised by the absence of paired fins, unpaired fins rudimentary or absent, presence of an accessory breathing organ, and vascular modifications which enable them to breathe atmospheric oxygen. They are distributed in freshwaters and occasionally brackishwaters across South and Central America, West Africa, large parts of Asia, and Australia.

The Abor Hills in British India referred to the region alongside the Siang River valley in present day Arunachal Pradesh. The Abor expedition (1911–1912) was military expedition undertaken by the British against the Adi people following the murder of a British officer.

During the expedition, many species of plants and animals were collected and among the species discoveries made by the expedition was Moringua hodgarti in 1913. The six specimens collected are currently kept at Zoological Survey of India in Kolkata.

“The species has not been collected since its original description and thus the paucity of specimens in collections has limited further enquiry. As part of a field survey carried out between January and October 2022, retracing the route of the 1911–1912 Abor Expedition we recovered specimens of a synbranchid eel from the vicinity of the type locality of Moringua hodgarti, as well as additional locations in the Siang Valley. Examination of the syntypes of Moringua hodgarti confirmed that our specimens represent this species, marking its rediscovery after 110 years,” the article mentioned.

While the species was earlier placed in the Moringua genus, the researchers after morphology and molecular analysis confirmed that Moringua hodgarti is a species of synbranchid eel of the genus Ophichthys and renamed it Ophichthys hodgarti.

“Our examination of part of the type series and freshly collected material confirms its placement in Ophichthys, based on the presence of scales over the entire body, and a modified gill arch skeleton,” the article said.

“The fact that over a century has elapsed between the description of Ophichthys hodgarti and its rediscovery serves to highlight the gaps in our knowledge of this highly cryptic and morphologically conservative group of fishes and suggests opportunities for researchers to intensify exploratory efforts to fill these gaps,” it added.