Taxonomic revision of the genus Equulites Fowler 1904 (Acanthuriformes: Leiognathidae)

This study is a taxonomic review of the ponyfish genus Equulites Fowler 1904 (Leiognathidae), which is diagnosed by the following combination of characters: downward projecting mouth; small teeth forming a narrow band on jaws; a dark blotch on neither nape nor spinous dorsal fin; clearing of the guanine-lined gas bladder extending to the full length of the bladder, not restricted posteriorly, a triangular or trapezoid translucent patch ventrolaterally on body in males; dark vermiculation, broad oblong ring markings and/or short oblique lines on the dorsolateral body. Ten species are herein recognized: three species of the Equulites elongatus species group [Equulites aethopos Suzuki and Kimura 2017—restricted to the southern Red Sea; Equulites elongatus (Günther 1874)—Myanmar, Indonesia and northern Australia; Equulites popei (Whitley 1932)—the Red Sea, Mozambique, Oman, Gulf of Thailand, Malaysia, Philippines and Japan, Mediterranean by Lessepian migration]; Equulites berbis (Valenciennes in Cuvier and Valenciennes 1835) (neotype designated herein)—widely distributed in the Indo-West Pacific, from the Red Sea and eastern coast of Africa to Indonesia, north to Japan, Mediterranean by Lessepian migration; Equulites laterofenestra (Sparks and Chakrabarty 2007)—Malaysia, Philippines, Indonesia and northern Australia; Equulites leuciscus (Günther 1860)—Seychelles, Myanmar, Thailand, Malaysia, Philippines, Indonesia, Papua New Guinea, northern Australia, Taiwan, and Japan; Equulites macrolepis sp. nov. Suzuki, Osmany and Kimura—Pakistan and western coast of Thailand; Equulites oblongus (Valenciennes in Cuvier and Valenciennes 1835) (lectotype designated herein)—India, Sri Lanka, Thailand, Malaysia, Philippines, Indonesia and Timor Island, north to Japan; Equulites rivulatus (Temminck and Schlegel 1845)—China, Taiwan, Korea and Japan; Equulites ryukyuensis sp. nov. Kimura and Suzuki—restricted to Okinawa, Japan. Diagnoses and descriptions (except for the Equulites elongatus species group) are provided for each species. The taxonomical status of Equula lineolata Valenciennes in Cuvier and Valenciennes 1835 is discussed.