Description of a New Species of Ponyfish (Teleostei: Leiognathidae: Equulitini: Photolateralis) from the Gulf of Oman

A new species belonging to the leiognathid genus Photolateralis, collected from the coastal waters of Oman, is described herein. Photolateralis is unique among leiognathid genera in possessing a species-specific translucent midlateral flank stripe that may be comprised of either multiple independent translucent windows (P. stercorarius, P. moretoniensis, and the new species) or a continuous translucent lateral band (P. antongil). Photolateralis polyfenestrus, new species, is distinguished from congeners by the presence of a short, composite midlateral stripe comprised of three small, rounded translucent windows (vs. numerous windows in both P. stercorarius and P. moretoniensis, or a continuous translucent stripe in P. antongil), and that is confined to the midflank (vs. extending a majority of the length of the flank in congeners). The new species is further distinguished from both P. moretoniensis and P. antongil by a shallower body, and from both P. stercorarius and P. moretoniensis by a pigmentation pattern above the lateral midline comprised primarily of larger rounded blotches (vs. smaller sinuous lines and markings comprising a vermiculated pattern). Photolateralis polyfenestrus is characterized by a lower jaw that is deep and convex in lateral view (vs. mostly straight in congeners, excluding P. antongil), and that forms an angle of between 60°–70° to horizontal (vs. less than 45° in congeners, excluding P. antongil). The only other species of Photolateralis reported from the Western Indian Ocean is P. antongil, to date only known from the coastal waters of Madagascar, whereas both P. stercorarius and P. moretoniensis have ranges restricted to the western Pacific and extending into the eastern Indian Ocean.