A New Species of Eagle Ray Aetobatus narutobiei from the Northwest Pacific: An Example of the Critical Role Taxonomy Plays in Fisheries and Ecological Sciences

Abstract

Recent taxonomic and molecular work on the eagle rays (Family Myliobatidae) revealed a cryptic species in the northwest Pacific. This species is formally described as Aetobatus narutobiei sp. nov. and compared to its congeners. Aetobatus narutobiei is found in eastern Vietnam, Hong Kong, China, Korea and southern Japan. It was previously considered to be conspecific with Aetobatus flagellum, but these species differ in size, structure of the NADH2 and CO1 genes, some morphological and meristic characters and colouration. Aetobatus narutobiei is particularly abundant in Ariake Bay in southern Japan where it is considered a pest species that predates heavily on farmed bivalve stocks and is culled annually as part of a ‘predator control’ program. The discovery of A. narutobiei highlights the paucity of detailed taxonomic research on this group of rays. This discovery impacts on current conservation assessments of A. flagellum and these need to be revised based on the findings of this study.

Aetomylaeus caeruleofasciatus, a new species of eagle ray (Myliobatiformes: Myliobatidae) from northern Australia and New Guinea

“…White et al 2010White et al , 2013 have shown that it can be very difficult to find good diagnostic characters to separate species which generally exhibit low levels of interspecific variability, but are also extremely intraspecifically variable. It is thus important to compare similar-sized specimens when trying to find useful characters to distinguish similar species.…”

Introductory Chapter: The Elasmobranchs as a Fishery Resource

“…In recent years, there have been considerable eforts in the Asian region, with wide-ranging phylogenetic and morphological inferences [5,6], as well as the description of new species [7,11,15] and the reinstatement of a number of families [8].…”

“…However, the full diversity of the elasmobranchs is still unclear, and a number of species have been described in recent years, principally from the waters of Asia and Oceania [5][6][7][8].…”

“…In recent years, the application of molecular tools in combination with morphological analyses has led to a signiicant increase in the known diversity of elasmobranch species [6,11]. One of the most important molecular tools is the DNA barcode [12], which provides a rapid and reliable approach for the identiication of taxonomic groups, especially those which may contain cryptic species, that is, taxa that are morphologically indistinguishable, but genetically distinct, highlighting the need for systematic reviews [7,13,14].…”

“…Recent studies of elasmobranch diversity have focused primarily on the Asian domain and have included the description of new species [5,7,15], the re-organization of some families [11], and the re-establishment of others [8]. All these diversities have been "discovered," thanks to the systematic combination of molecular and morphological approaches, with molecular tools being especially useful for the delimitation of groups or species thought to contain cryptic diversity [16,17] or that need internal review [18].…”