340 Memoir Sears Foundation for Marine Research 



amination of a considerable series, we conclude that the most workable subdivision 

 of the group of species in question is as follows: (a) those in which the tail bears neither 

 membranous folds nor well marked longitudinal ridges either above or below (genus 

 Himanturd), and (b) those in which there is a membranous fold on the lower surface 

 of the tail, with or without a fold or ridge above (genus Dasyatis). 



Key to Genera 



I a. No spine on tail. Urogymnus Miiller and Henle 1837." 



Australia, East Indies, Indian Ocean, Red Sea. 

 I b. Upper surface of tail with a large serrated spine (or spines). 



2a. Lower tailfold extending to tip of tail. Taeniura Miiller and Henle 1837. 



Red Sea, Indian Ocean south on African Coast 

 to Delagoa £37,^' East Indies, Philippines, 

 Australia, Polynesia; also Mediterranean and 

 Cape Verde Islands. 

 2 b. Lower tailfold either lacking or terminating far short of tip of tail. 



3a. Tail shorter than disc. Urolophoides Soldatov and Lindberg 1930. 



Peter the Great Bay, Northeast Asia; doubtful genus. ^^ 

 3 b. Tail longer (usually much longer) than disc. 



4 a. Lower surface of tail, posterior to spine, without membranous fold, 

 either rounded or at most with a low cutaneous ridge. 



Himantura^" Miiller and Henle 1837, p. 389. 



4 b. Lower surface of tail posterior to origin of spine with a longitudinal 



membranous fold. Dasyatis Rafinesque 18 10, p. 340. 



Genus Dasyatis Rafinesque i 8 i o 



Dasyatis Rafinesque, Carratt. Gen. Spec. SiciL, 1810: 16; type species, D.ujo Rafinesque, Sicily, equivalent 

 to Raja pastlnaca Linnaeus 1758.^1 



with the rank of full genera, and Whitley (Fish. Aust., i, 1940: 200-208) recognizes four genera of long-tailed 

 Rays with tail spines but without definitions. 



27. Urogymnus MuUer and Henle 1837 is antedated by Anacanthus Ehrenberg 1833 (in Van der Hoeven, Handb. Dier- 

 kunde, 2, 1833: 179), but this name was preoccupied by Gray 1831 for teleost fishes and by Audinet-ServiUe 1832 

 for Coleoptera. To replace ^wacawMa/ for the genus of Rays in question. Cantor (Malay. Fish., 1849: 1404) proposed 

 RJiachinotus, which was accepted by Garman (Mem. Harv. Mus. comp. Zool., 36, 1913: 373) in spite of the fact 

 that the older name Urogvmnus Muller and Henle 1837 (Arch. Naturg., J, 1837: 437) was expressly based on the 

 same species {Raja asperrima Bloch and Schneider 1801) that was later christened Rhachinotus afrkanus by Cantor. 

 The name Urogymnus was revived by Ogilby (Mem. Qd. Mus., 5, 1916: 88) and has been used by subsequent 

 writers generally. 



28. Reported from Delagoa Bay by Smith (Sea Fish. S. Afr., 1949: 70). 



29. The original and only account of this Ray (Soldatov and Lindberg, Bull. Pacif. Sci. Fish. Inst., 5, 1930: 24), from 

 a mounted specimen, records an upper tailfold but fails to state whether or not there was a lower tailfold. The ac- 

 count of the tail as stout with blunt tip leaves open the possibility that its shortness (only about Vs ^s long as the 

 disc) may have been due to mutilation, followed by subsequent healing of the wound; specimens with tails in this 

 state are often seen among other species of Sting Rays. 



30. Himantura was proposed by MuUer and Henle (Arch. Naturg., 3 [i], 1837: 400) with diagnosis but without mention 

 of any particular species. Dumeril (Hist. Nat. Poiss., j, 1865: 585), however, referred a considerable list of species 

 to it, including Raja uarnak Forskal 1775, which was later designated as the type species by Garman (Mem. Harv. 

 Mus. comp. Zool., j6, 1913: 375). 



31. Besides the synonyms listed here. Fowler (Bull. U.S. nat. Mus., 100 [jj], 1941: 402) includes the fossil genera 



