New biological data relevant to the conservation of the rare and threatened shark Carcharhinus leiodon are presented, based on specimens sampled in fish markets in Kuwait, the UAE and Yemen. The maximum size of this species
is extended to 1648mmtotal length (TL); females are mature by at least 1312mmTL and demonstrate placental viviparity with litters of 4–6 embryos. In the north-western Persian Gulf there is evidence that parturition occurs in spring when embryos are ,350–515mm TL, with at least some neonate individuals probably remaining in the area through the summer. Further records of C. leiodon from the western Arabian Sea indicate that adults are present in this region throughout the year. Landings of C. leiodon apparently caught in the eastern Persian Gulf may extend the highly fragmented known distribution of this species. Contrary to an earlier study, the first detailed examination of dissected adult C. leiodon jaws revealed that fine serrations are present on upper teeth, and characters are provided to separate the dentition and jaws of C. leiodon from congeners. The stomach of an adult C. leiodon contained bentho-demersal fish, and an individual with fin abnormalities is noted.