Yellowspotted Fanray: Platyrhina tangi

Family: Platyrhinidae

Common name(s)

Yellowspotted Fanray, Thornback Ray.

Identification

A medium-sized fanray with a heart-shaped disc, an obliquely pointed snout, and a broad torso. Pectoral fin apices broadly rounded. Pelvic fins long and low, with broadly rounded outer margins and acutely angular free rear tips.
Eyes somewhat protruding, and closely spaced. Nostrils thin, well separated, and positioned somewhat obliquely. Nostrils connected to mouth by a wide groove.
Skin covered in small dermal denticles. Short thorns present on midline from nape to second dorsal fin. Two pairs of large, flattened, oval thorns present on inner and outer shoulders. Two large thorns anterior, and 2 thorns posterior to each eye.
Tail long and broad; tapering gently to terminal lobe. Two high dorsal fins with rounded apices and mildly convex posterior margins present on posterior tail. Origin of first dorsal fin approximately at mid tail. Caudal lobe large and spatulate. Caudal sting absent.

Colour

Dorsum greyish brown, beige, or brown, sometimes with a dusky stripe along midline. Enlarged thorns on midline, shoulders, and around eyes yellow – collectively forming a dotted, yellow cross. Ventrum white, usually with a few grey blotches. Dusky towards ventral margin of disc.

Size

Maximum length at least 64cm, probably 70cm. Size at birth unknown.

Habitat

Benthic in tropical to Warm-temperate seas. Rocky and sandy substrates from surface to 100m but usually 30-40m.

Distribution

Northwest Pacific. Found from southern Japan, Korea, China, and Taiwan.

Conservation Status

VULNERABLE

Indo-west Pacific fanrays were recently split into 4 distict species but they are still referred to collectively by the IUCN as Chinese Fanrays – Platyrhina sinensis. Consequently, the following assessment is out of date and may need to be upgraded for some regional species:

The Fanray (Platyrhina sinensis) is restricted to inshore waters to depths of 100 m (but most commonly at 30–40 m). It is a utilised bycatch of gillnet, coastal set-net and trawl fisheries, and is very easily captured in almost any coastal fishery. Although not targeted, the catch is often retained and sold. Its susceptibility to capture in a variety of fishing gears and preference for inshore sandy habitats that are generally heavily fished make it vulnerable to depletion. It is reported to have declined in both abundance and extent of occurrence in the East China Sea, where it was, formerly, commonly captured by bottom trawls. In southern Japan, at the northern edge of its range, it is reportedly still common. Although no specific information on population trends is available from the southern half of its range, inshore fisheries are intense there and this species, like many other batoids in the region, is likely to have declined. The species is therefore assessed as Vulnerable globally, on the basis of a continuing decline in abundance and area of occurrence, over the three generations. Further investigation is required into catch levels and population trends throughout the species’ range.

Citation

Ishihara, H., Wang, Y., Tanaka, S. & Nakaya, K. 2009. Platyrhina sinensis. The IUCN Red List of Threatened Species 2009: e.T161589A5458790. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161589A5458790.en. Downloaded on 15 March 2021.

Reproduction

Aplacental viviparous with yolk sac. Litter size unknown.

Diet

Diet consists of small shrimps, mysids and small fish.

Behavior

Poorly known.

Reaction to divers

Remains motionless unless disturbed.

Diving logistics

Sightings of yellowspotted fanrays while on scuba are rare. Due to poor visibility along the coast of mainland China, the best area to look for this species is probably southern Japan. Searching on sandy substrates adjacent to deep rocky reefs at 30-40m should be the most productive.