A collection of nine shark specimens from six different species, obtained in 1993 from the Gulf of Thailand, was examined in this study. The sharks were determined, morphometrically and meristically analyzed, photographically documented, and compared with relevant literature. Additionally, further available material from the fish collections of the Zoological Museum Hamburg, the Senckenberg Naturmuseum Frankfurt, and the Muséum national d’Histoire naturelle, Paris, was examined by way of comparison. Contrary to most references, prominent dorsal ridges were detected in several specimens of Chiloscyllium griseum. Additionally, one of the specimens had a very unusual big ocellar blotch on the head which had not been reported for this genus before. For Paragaleus randalli, it could be proven that the teeth morphologically deviate strongly from those shown in literature due to having much larger cusps. Furthermore, the known distribution area of Paragaleus randalli could be extended considerably eastwards by about 2000？km. For a seventh species, Paragaleus tengi, differences between the actual morphology of upper lateral teeth and those drawn in the original description were detected. 1. Introduction About 500 of the more than 1200 globally known species of Chondrichthyes are sharks, including the world’s biggest fish species [1]. The highest diversity of Chondrichthyes can be found in the East Indian Ocean [2–4], where the catches of elasmobranch fishes have increased significantly over the last decades from 18？600 t in 1950 to 77？700 t in 1997 [5]. Today Indonesia has the world’s largest chondrichthyan fishery [3]. Extensive targeted fishery and bycatch belong to the most important reasons for the recent decline of the populations of many elasmobranch species [6, 7]. Sharks are especially susceptible to population declines because the lifestyle of many species is characterized by late attainment of sexual maturity, slow growth, and low reproductive output [2, 8, 9]. Due to the numerous population declines, it is very important to develop management and protection programs for many elasmobranch species, which require well-founded knowledge about the taxonomy, distribution, and abundance of the species. However, although many new elasmobranch species have been described in recent years [1, 10–13], the knowledge on many known species is still scarce due to the often very old and sketchy original descriptions like those by Müller and Henle [14]. Another reason for the gaps in knowledge is the often insufficient declaration of elasmobranch catches by fishermen,
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