Re-description of the longtail butterfly ray, Gymnura poecilura (Shaw, 1804) (Gymnuridae: Myliobatiformes) from Bay of Bengal with a neotype designation

Abstract

The longtail butterfly ray, Gymnura poecilura, was originally described as Raja poecilura by Shaw 1804 without any type material, based on Russell’s (1803) illustration of “Tenkee kunsul” from Vizagapatam (present day Visakhapatnam), India. Because of the absence of detailed taxonomic accounts for G. poecilura, characters mentioned for its identification are often misleading and unreliable, leading to frequent misidentification of the species with congeners in the region. In the absence of type specimens or detailed taxonomic work on the genus Gymnura from the Indian Ocean region, species G. poecilura is considered to be undefined. In an effort to clear up the taxonomic vagueness of the species, this article re-describes G. poecilura from fresh materials, designates a neotype from Visakhapatnam, India (western Bay of Bengal) and also reports the presence of a distinct Gymnura species from the northern Arabian Sea with genetic support. Reports of two butterfly rays, G. japonica and G. micrura, from Indian waters are clarified as misidentifications and so must be excluded from the Indian elasmobranch faunal list.