Marine biologists from Japan and Australia have described a new species of eagle ray in the genus Aetobatus.
Aetobatus narutobiei, adult male. Image credit: White WT et al.
Eagle rays are a diverse group of cartilaginous fishes in the family Myliobatidae. They are well known aerial acrobats, leaping out of the water to considerable heights.
These rays spend a lot of their time in groups near the surface of the water, but still feed on shellfish on the sea floor.
The newly discovered species, Aetobatus narutobiei, is a medium- to large-sized Aetobatus ray, measuring up to 1.5 m in width. It is found in the waters off eastern Vietnam, Hong Kong, China, Korea and southern Japan.
Aetobatus narutobiei was previously considered to be conspecific with the Longheaded eagle ray (Aetobatus flagellum), but these species differ in size, structure of some genes, morphological and meristic characters and coloration.
According to the scientists, 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.
Lateral head view of Aetobatus narutobiei. Image credit: White WT et al.
“Aetobatus narutobiei most closely resembles Aetobatus flagellum but is clearly distinguishable based on the following characters: larger maximum size; larger size at maturity and at birth; possibly greater number of tooth series; more metapterygial pectoral-fin rays and total, excluding propterygial rays anterior to eyes, pectoral-fin rays; more pelvic-fin rays,” lead author Dr William White of CSIRO Marine & Atmospheric Research in Tasmania and his colleagues wrote in a paper in the open-access journal PLoS ONE.
“Aetobatus narutobiei also appears to have a much longer lower tooth band than Aetobatus flagellum, but this is based on only a single specimen of each species and thus intraspecific differences cannot be adequately ascertained.”
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White WT et al. 2013. 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. PLoS ONE 8(12): e83785; doi: 10.1371/journal.pone.0083785
