Ecsenius niue, new species of blenniid fish, and new distribution records for other species in the Opsifrontalis species group

Ecsenius niue is described from Niue Islands, SW Pacific. It is a member of the Opsidrontalis species group and is most similar to the Fijian endemic E. fijiensis, from which it differs in having six, as opposed to seven, vertical pairs of dark spots on the body posterior to a vertical from the base of the first segmented dorsal-fin ray, and in having the posteriormost pair of dark spots posteriorly elongate and attenuating onto the base of the caudal fin, as opposed to the spots being roughly cicular and discrete. It differs from the superficially similar E. tigris (islands of the Queensland Plateau) in lacking the three of four dark spots on the body ventral to those on the dorsal body contour below the spinous dorsal fin. New distribution records are given for E. axelrodi, E. bathi, and E. opsifrontalis.