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Issue: Vol. 5866 No. 1: 10 Aug. 2026
Type: Article
Published: 2026-08-10
DOI: 10.11646/zootaxa.5866.1.9
Page range: 124-134
Abstract views: 444
PDF downloaded: 21

A new species of the deepwater goby Obliquogobius (Gobiiformes: Gobiidae) from the southwestern Indian Ocean

The Kyoto University Museum; Yoshida Honmachi; Sakyo-ku; Kyoto 606-8501; Japan.
National Research Foundation—South African Institute for Aquatic Biodiversity; Makhanda 6140; South Africa.
Tanzania Fisheries Research Institute (TAFIRI); Dar Es Salaam Centre; P.O. Box 9750 Dar Es Salaam; Tanzania.
National Research Foundation—South African Institute for Aquatic Biodiversity; Makhanda 6140; South Africa.
Pisces Teleostei taxonomy morphology Tanzania Madagascar R/V Dr. Fridtjof Nansen

Abstract

The deep-water goby genus Obliquogobius is a small but steadily growing group of cryptobenthic fishes of the outer shelf and upper continental slope, currently comprising nine valid species distributed across the Indo-West Pacific. Its taxonomic and biogeographic resolution remains poor in the Western Indian Ocean, where only two species, O. cometes and O. turkayi, have been formally confirmed. During the 2023 EAF-Nansen Programme survey of Tanzania’s Exclusive Economic Zone, 20 specimens (33.2–44.7 mm SL) were trawled at 215–277 m depth by the R/V Dr. Fridtjof Nansen. They are described here as Obliquogobius nansen sp. nov., the first species of the genus described from the southwestern Indian Ocean. In addition, eleven specimens (40.0–53.5 mm SL) collected from Madagascar were assigned to the new species. The new species is most similar to O. yamadai in overall coloration and in the pattern of cephalic sensory-canal pores; however, it is readily distinguished by a generally straight (not posteriorly inclined) anteriormost body bar, the first dorsal fin entirely black except for the distal margin, two longitudinal yellow stripes on the second dorsal fin, a 90°-clockwise-turned T-shaped black mark on the caudal-fin base, and four longitudinal yellow stripes on the caudal fin. Maximum-likelihood analysis of the mitochondrial COI barcode region recovers O. nansen as sister to O. yamadai, from which it diverges by 7.1–7.3% (uncorrected p-distances).

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How to Cite

Fujiwara, K., Bogorodsky, S.V., Matiku, P. & Matcher, G. (2026) A new species of the deepwater goby Obliquogobius (Gobiiformes: Gobiidae) from the southwestern Indian Ocean. Zootaxa, 5866 (1), 124–134. https://doi.org/10.11646/zootaxa.5866.1.9