RESEARCH ARTICLE

A new species of longnose skate Dipturus (Rajiformes: Rajidae) from the western Indian Ocean, with a redescription of Dipturus johannisdavisi.

K.K. Bineesh, Anil Kasinath, K.V. Akhilesh & David A. Ebert

The longnose skate genus Dipturus Rafinesque, 1810 (Rajiformes: Rajidae) is poorly documented in the northern Indian Ocean, where the species diversity and taxonomy remain inadequately resolved. The Travancore Skate, Dipturus johannisdavisi (Alcock, 1899), originally described from a single juvenile specimen, has not been formally redescribed, resulting in persistent uncertainty regarding its diagnostic characters and taxonomic status. Recent collections of Dipturus skates landed as bycatch from deep-sea trawl fisheries along the southwest coast of India included both D. johannisdavisi and an undescribed species of Dipturus captured from depths of 400-600 m. We describe the new species, the Arabian Skate, as Dipturus dhritiae, sp. nov. It can be distinguished from close congeners by a combination of morphological characters, including disc proportions, thorn arrangement, and meristic counts, as well as by a 3.8-6.1% Kimura 2-parameter (K2P) pairwise difference in available mtDNA-barcode sequences. In addition, we present a comprehensive redescription of D. johannisdavisi based on the newly collected material from the southeastern Arabian Sea, incorporating detailed morphometric and meristic data together with COI mtDNA sequencing. These comparative morphological and molecular analyses clarify the taxonomic identity of D. johannisdavisi. Our findings reveal previously unrecognized diversity within Dipturus skates in Indian waters and provide a robust framework for future taxonomic, ecological, and conservation assessments of skates in the region.

CITATION:

Bineesh, K.K., Kasinath, A., Akhilesh, K.V. & Ebert, D.A. (2026) A new species of longnose skate Dipturus (Rajiformes: Rajidae) from the western Indian Ocean, with a redescription of Dipturus johannisdavisi. Journal of the Ocean Science Foundation, 47, 24-40.

https://doi.org/10.5281/zenodo.21999977

publication date: 28 August 2026