| Longtail butterfly ray | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Order: | Myliobatiformes |
| Family: | Gymnuridae |
| Genus: | Gymnura |
| Species: | G. poecilura |
| Binomial name | |
| Gymnura poecilura (G. Shaw, 1804) |
|
| Synonyms | |
|
Pastinaca kunsa Cuvier, 1829 |
|
The longtail butterfly ray (Gymnura poecilura) is a species of butterfly ray, family Gymnuridae. It has a wide but apparently non-continuous distribution in the Indo-West Pacific, occurring in the Red Sea, Somalia, and Oman, and from Pakistan to Indonesia to southern Japan. There is also an isolated population in French Polynesia. Its presence is unconfirmed between Oman and Pakistan. It is found over sandy or muddy bottoms in shallow inshore waters or offshore banks to a depth of 30 m.[1][2]
This species is distinguishable from other butterfly rays in that the distance from the tip of its snout to its cloaca is the same as that from the cloaca to the tip of its tail.[3] Its body has the characteristic shape of the butterfly rays, with a pectoral fin disc twice as wide as it is long. The front margin of the disc has a slight sinuous curve, the rear margin is convex, and the tips are little rounded. The snout has a small, pointed projection at the tip. There are no dorsal or caudal fins, and there is a small venomous spine at the base of the tail. The disc is light brown above with small white spots and sometimes scattered small dark brown spots. The tail has 8-9 each of alternating black and white rings, the white with a small dark dorsal spot (sometimes only on bands near the tail base).[4] The maximum known disc width is 91.5 cm.[1]
The diet of the longtail butterfly ray includes fishes (especially Leiognathus), molluscs, and crustaceans. It is ovoviviparous, with a maximum fecundity of seven young. There is apparently no relationship between fecundity and female size, although this information may be confounded by the fact that females often spontaneously abort young upon capture. Breeding takes place year-round, with parturition peaking between April and October. This species is targeted by artisanal fisheries in India, Thailand and Indonesia, where it is utilized for human consumption. It is also taken as by-catch by fisheries in other parts of its range. Due to its low fecundity, restricted habitat, and susceptibility to exploitation, the longtail butterfly ray was assessed as Near Threatened in the IUCN Red List pending more concrete population and capture data.[1]