Thirty-eight species of moray eels (Muraenidae) from the Red Sea are reported in an updated review. A species account is provided for each species, along with a full synonymy of all nominal species described from the Red Sea. One species is new to science, G. pharaonis, and two species are new for the Red Sea, Gymnothorax phasmatodes (Smith) and Scuticaria tigrina (Lesson). Gymnothorax pharaonis n. sp. is a common species that has long been misidentified as G. undulatus (Lacepède), although it more closely resembles G. margaritophorus Bleeker, to which it is closely related phylogenetically. It is characterized by the following combination of characters: total vertebrae 123-128; body slender, depth at anus 17-28 in TL; maxillary teeth biserial, dentary and vomerine teeth in a single row; color brown with irregular dendritic pale markings, not interconnected or chain-like, with oblique, conspicuous, parallel streaks posteriorly in dorsal fin. The new record of the distinctive whitish G. phasmatodes is based on an underwater photograph taken at Jeddah, Saudi Arabia. The new record of Scuticaria tigrina is based on a specimen collected from Jeddah, Saudi Arabia, and underwater photographs taken from the northern part of the Red Sea. Based on an integrative taxonomical approach by a combination of morphological and phylogenetic analyses and re-examination of holotype specimens, Gymnothorax cinerascens (Rüppell) is resurrected as a valid species, and it is shown that previous records of G. hepaticus (Rüppell), with which it has previously been synonymized, should refer to G. cinerascens. The true G. hepaticus is redescribed based on examination of the holotype and additional specimens collected during the course of this study. The two species are distinguished by the color of the jaws, the position of the median intermaxillary teeth, and a slight difference in the preanal length. They are also clearly distinct genetically. The Red Sea record of Gymnothorax atolli (Pietschmann) is based on an error, possibly a misidentification of G. griseus (Lacepède). A key to the species of Red Sea moray eels and a phylogenetic tree of presently known lineages of Indo-Pacific moray eels are provided including recently collected Red Sea specimens.
Keywords: Pisces, Muraeninae, Uropterygiinae, systematic, phylogenetic analysis, Egypt, Saudi Arabia.