The new species of deep-water dogfish shark Squalus hima 
| Photo Credit: Special Arrangement

Scientists from the Zoological Survey of India (ZSI) have discovered a new species of deep-water dogfish shark Squalus hima from Sakthikulangara fishing harbour in Kerala along the Arabian Sea.

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Squalus is a genus of dogfish sharks in the family Squalidae. commonly known as spurdogs, and are characterized by smooth dorsal fin spines.

The discovery has been made by a team of scientists led by Bineesh K. K Scientist at the Marine Biology Regional Centre of ZSI and the discovery has recently been published in the journal Records of the ZSI.

“This species has been largely misidentified with S. mitsukurii and S. lalannei. However, morphological, meristic, morphometric evidence support it to be a separate and undescribed species. Squalus hima sp.nov differs from other species by the number of precaudal vertebrae, total vertebrae, teeth count, trunk & head heights, fin structure and fin colour,” said by Sweta Beura, lead author of the publication. 

In the Indian coast, two species of Squalus are found from the southwest coast of India and the new species, Squalus hima n.sp. very similar to Squalus lalannei, but differs in many characteristics.

The species belonging to Squalus megalops group are characterised by an angular short snout, a small mouth almost as wide as the snout, first dorsal fin origin behind the pectoral fins, and body without any spots.

Dr. Bineesh explained that the shark species belonging to the genus Squalus and Centrophorus are exploited for their liver oil that contains high levels of squalene (or squalane is when it is processed for products). It is in high demand for pharmaceutical industries particularly for making high end cosmetic products and anti cancerous products.

“ Fishermen from the southern coast of India and Andaman and Nicobar Islands are exploiting several such families of sharks to harvest their liver oil for the pharmaceutical industry. The discovery of the new species is important to conserve such varieties of shark,” Dr. Bineesh said,

The scientist added that dogfish sharks represent commercially important taxa because of their trade for their fins, liver oil and meat. Squalus species are also sometimes caught incidentally as bycatch in fisheries targeting other species.

Dhriti Banerjee, director of ZSI, lauded the discovery of a new species of dogfish shark and said that the Survey is conducting deep sea habitat explorations at depths of 1000-3000 metres to find out species diversity of sharks and rays under the special programme of Deep Ocean Mission of Ministry of Earth Sciences.

Dr. Bineesh said that his team has explored sharks and rays in the seas along the country’s coastline to a depth of about 1000 metres and in the next phase the species diversity upto 2000 metres will be explored.

This species Squalus hima is described on the basis of 13 specimens collected from the southwest coast of India during the surveys conducted to understand the diversity and distribution of deep-sea sharks from the Indian EEZ ( Exclusive Economic Zone).

A photograph of Melanochlamys droupadi, a head-shield sea slug with ruby red spot.
| Photo Credit: Special Arrangement

The Zoological Survey of India named a new marine species of head-shield sea slug with ruby red spot which was discovered from West Bengal and Odisha coast after President of India Droupadi Murmu.

This species belonging to Melanochlamys genus was discovered from Digha of West Bengal coast and Udaipur of Odisha coast. The new species of head-shield sea slug, which is found nowhere in the world, is named as Melanochlamys droupadi.

Species of the genus Melanochlamys are characterised morphologically by a short, blunt and cylindrical body and a smooth dorsal surface with two dorsal equal or unequal shields, named the anterior cephalic and posterior shield

In a statement, Dhriti Banerjee, ZSI director, said, “The species was confirmed by examination of morphological, anatomical and molecular characteristics. It is a small invertebrate with a maximum length up to 7 mm, brownish black in colour with a ruby red spot in the hind end, shell inside the body, hermaphrodite, normally crawling on the intertidal zone, which left the crawl mark behind them in the sandy beaches.”

“Their reproduction apparently occurs between November and January. The locality was designated as Hospital Ghat, Old Digha, which just 50 metre away from Marine Aquarium Regional Centre, Zoological Survey of India, Digha. The type specimens were deposited in Marine Aquarium and Regional Centre, Digha and Estuarine Biology and Regional Centre, Gopalpur,” she said.

According to ZSI, species of this group are generally distributed in temperate regions of the Indo-Pacific Oceanic realm but three species are truly tropical distributed, Melanochlamys papillata from the Gulf of Thailand, Melanochlamys bengalensis from West Bengal and Odisha coast and the present species.

A scientific paper published by ZSI researchers Prasad Chandra Tudu, Sheikh Sajan, Smrutirekha Acharya and Anil Mohapatra says live Melanochlamys droupadi animals continuously secrete transparent mucus to form a sheath that prevents sand grains from entering parapodial space. It crawls beneath smooth sand to form a moving capsule where the body is rarely visible, the paper said.