Relevant synonyms Trygon uarnak Dasyatis uarnak Misidentification None  photo : David Darom

SHORT DESCRIPTION Body flat, almost rhomboid shaped, with nearly straight anterior margins, snout obtusely triangular. Pectoral fin apex rounded (in juveniles) to nearly rounded in adults. Spiracles situated closely posterior to eyes. Mouth with 4-5 fleshy papillae. Long whip-like tail, 2.5-3.5 longer than disc width with one (rarely two) serrated spines close to its base. Upper surface mostly smooth, with a series of medium small flattened tubercles from eyes to tail base. color : upper surface light brown to greyish-yellow with numerous dark brown spots. Lower surface white. size : common disc diameter 40 - 120 cm (max. 50 cm). DISTINGUISHING CHARACTERISTICS Taniura grabata: posterior part of tail has membranous fold below. Dasyatis spp. Upper surface more or less uniform in color (some D. pastinaca specimens have a bluish-grey pattern on a brown-olive background). Rajidae: body covered, at least partially, with prickles and/or thornlets; no whip-like tail. Myliobatidae, Rhinopteridae and Mobulidae: head distinctly protrudes from body. Gymuridae: tail shorter than disc width. BIOLOGY / ECOLOGY Feeds on fishes, crustaceans and, to a lesser extent, on molluscs. An ovoviviparous species. Reaches sexual maturity at the age of 4 (disc diameter 1 m). 3-5 offspring of 20 cm disc diameter born after one year gestation. habitat : inhabits sandy or muddy substrates at depths to 50 m. Known as a euryhaline species often penetrating estuaries.

1st MEDITERRANEAN RECORD Israel, 1955. DISTRIBUTION Worldwide : species recorded in the literature as having a wide Indo-Pacific distribution from the Red Sea, Eastern Africa to Northern Australia and the Philippines. However, since H. uarnak is often confused with other closely-related species, its true distribution range will be known only after taxonomic study of the entire complex. Mediterranean : recorded first from Israel (Ben Tuvia, 1955) ; successive records in Mersin, Turkey (Ben-Tuvia, 1966), Lebanon (Mouneinne, 1977), Egypt (El Sayed, 1994), Turkey (Basuta et al., 1998). ESTABLISHMENT SUCCESS Prevalent with steady population. speculated reasons for success : unknown. MODE OF INTRODUCTION Via the Suez Canal. IMPORTANCE TO HUMANS Large specimens are often caught in trawl. Not commercially important.

KEY REFERENCES Ben-Tuvia A., 1955. Two Indo-Pacific fishes, Dasyatis uarnak and Upeneus moluccensis, in the eastern Mediterranean. Nature, 176:1177-1178. Last P.R. and Stevens J.D., 1994. Sharks and Rays of Australia. CSIRO Division of Fisheries, Australia. 513 pp. +84 plates. FEEDBACK / COMMENTS TO AUTHORS

Last update of the species sheet: April 2002 ©ciesm 2002