* 2011: Zootaxa, 2738: 26–40. Preview
Platyrhina is a genus of rays in the family Platyrhinidae, containing two species. They are native to the warm-temperate to tropical marine waters in the western Pacific Ocean. Both species are little-known bottom-dwellers that feed on small invertebrates such as crustaceans, molluscs, and worms. The fanray is found inshore to a depth of 60 m on rocky or rock sandy bottoms.
Platyrhina species have rounded heart-shaped pectoral fin discs with short, blunt snouts. Their tails are long and shark-like, slightly flattened with lateral ridges. The two dorsal fins and the caudal fin are large and rounded; the caudal fin lacks a lower lobe. The teeth are small and arranged in pavement-like rows for crushing shelled prey. Their bodies are covered with minute dermal denticles; there are also several rows of denticles inside the buccopharyngeal cavity. The shape of these denticles in Platyrhina and the similar Platyrhinoidis distinguish them from all other guitarfish species. There are large thorns around the eyes and on the shoulders, and arranged in rows along the back and tail. Unlike Platyrhinoidis, Platyrhina species have an additional lateral row of thorns on both sides of the tail, and no rostral thorns.
As far as known, both species are ovoviviparous, with the developing fetuses primarily sustained by large yolk sacs. The Amoy fanray has been reported to give birth to litters of 10 in July and August. Research on fanrays in Ariake Bay, Japan, indicates that they are faster-growing, earlier-maturing, and shorter-lived than many other ray species. Male fanrays mature at 2.1 years and females at 2.9 years; the females grow larger and more slowly than males. The maximum known age is 5 years for males and 12 years for females. These rays are typically inoffensive but care should be exercised regarding their large, sharp thorns.
* Amoy fanray, Platyrhina limboonkengi Tang, 1933 This species occurs off the coast of China, in the East China Sea and the South China Sea. It usually grows to a size of 40-50 cm. The coloration is green-brown above and white below. It differs from P. sinensis in the shape of its thorns and the placement of the lateral row of thorns on its tail. The flesh is considered of poor taste, and it is more often sold dried and salted than fresh.
* Fanray or thornback ray, Platyrhina sinensis (Bloch & Schneider, 1801) This species is locally common off the coasts of China, Japan, Taiwan, Korea, Vietnam, and possibly Indonesia. It grows to a maximum known length of 68 cm, but most are 30-50 cm and weigh 200-500 g. The coloration is brown above and white below. The flesh is edible but this species is not targeted by fisheries. The fanray is the most abundant elasmobranch species in Ariake Bay, Kyūshū; it is caught as bycatch in gillnets and trawls and discarded, but its population has not been negatively affected by these activities.
1. ^ a b c d e Compagno, L.J.V. and Last, P.R. (1999). "Platyrhinidae: Thornback rays". In Carpenter, K.E. and Niem, V.H.. FAO identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Rome: Food and Agricultural Organization of the United Nations. ISBN 9251043027.
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License