First record of oarfish, Regalecus russellii (Actinopterygii, Lampriformes, Regalecidae), from Sri Lankan waters, Indian Ocean

Abstract

Oarfishes, representing the family Regalecidae, are poorly known from the tropical Indian Ocean and are of exceptional interest in terms of their distribution. This study presents the first detailed morphological description of Regalecus russellii (Cuvier, 1816) based on the single specimen (2580 mm total length) collected from Sri Lankan waters on 27 October 2021. The morphological characters of the presently reported specimen well matched the key identification features of R. russellii reported from the eastern and western Pacific Ocean, and the Atlantic Ocean. This report of R. russellii from the Indian Ocean provides vital information on their biology and distribution.