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Scientists of the Zoological Survey of India, working with ICAR-Central Marine Fisheries Research Institute and international collaborators, have described a new deep-sea skate from the southeastern Arabian Sea.
Named Dipturus dhritiae and given the common name Arabian skate, it was collected off the Kerala coast and in the Wadge Bank region at depths of roughly 400-600 metres.
The species grows to about 1.3 metres and is distinguished by five rows of thorn-like structures running along its tail.
The name honours Dr Dhriti Banerjee, the first woman Director of the Zoological Survey of India.
The find comes out of survey work on India's deep-sea sharks, rays and skates carried out under the Deep Ocean Mission.
Skates belong to the class Chondrichthyes, whose skeletons are made of cartilage rather than bone, and within it to the batoids, the flattened group that also contains rays. The everyday test that separates the two is reproduction: skates are egg-laying, depositing tough leathery egg cases often called mermaid purses, while most rays give birth to live young. Skates also have fleshy tails carrying rows of thorns and no venomous sting, whereas many rays carry a barbed spine. Deep-sea skates sit at the slow end of life-history strategies: they mature late, produce few offspring and take a long time to rebuild numbers, which is precisely why trawl bycatch hits them harder than it hits fast-breeding bony fishes.
Simple Analogy: If a shark is a fast car built for the open road, a skate is the same engineering flattened into a paving slab, parked on the seabed and reproducing at the pace of a slow-growing tree.
The specimens came from the southeastern Arabian Sea off India's southwestern coast, including the Wadge Bank. The Wadge Bank is a shallow, exceptionally productive continental-shelf fishing ground lying south of Kanyakumari, roughly 80 km seaward of the coast. Its status is settled by the India-Sri Lanka maritime boundary agreement of 23 March 1976, under which Sri Lanka accepted that the Wadge Bank falls within India's exclusive economic zone and that India holds sovereign rights over the area and its resources.
The 1976 agreement that confirmed India's rights over the Wadge Bank is the sequel to the 1974 accord under which Katchatheevu was recognised as Sri Lankan territory; the two are routinely examined together.
Deep-sea biodiversity survey is one of the mission's components; Samudrayaan and Matsya 6000 are the engineering components of the same programme.
Several sharks and rays in Indian waters are listed in the schedules of the Wild Life (Protection) Act, 1972, and traded species are regulated through CITES appendices.
Naming a taxon after a scientist is a patronym, the same convention that produced Nereis dhritiae and Exostoma dhritiae, both also named for the ZSI Director.
GS Paper 3 > Environment and Biodiversity > Conservation and species discovery
General Awareness > Current Affairs > Science and Environment
An egg-laying, flattened cartilaginous fish of the batoid group, distinguished from most rays by laying eggs in leathery cases and lacking a venomous sting.
The class of fishes with cartilaginous skeletons: sharks, rays, skates and chimaeras.
A scientific name formed in honour of a person, as dhritiae honours Dr Dhriti Banerjee.
A rich continental-shelf fishing ground south of Kanyakumari, confirmed as lying within India's EEZ by the 1976 India-Sri Lanka maritime boundary agreement.