Melon-Headed Whale: Peponocephala electra

Abstract

Publisher Summary The melon-headed whale is one of a group of small, dark-colored whales that are often referred to as “blackfish.” It is mostly dark gray in color with a faint darker gray dorsal cape that is narrow at the head and dips downward below the tall, falcate dorsal fin. A faint light band extends from the blowhole to the apex of the melon. A distinct dark eye patch, which broadens as it extends from the eye to the melon, is often present and gives this small whale the appearance of wearing a mask. The lips are often white, and white or light gray areas are common in the throat region and stretching along the ventral surface from the leading edge of the umbilicus to the anus. At sea, this species is difficult to distinguish from the pygmy killer whale (Feresa attenuata). It differs externally from the pygmy killer whale by having a more pointed or triangular head and sharply pointed pectoral fins. The skull of the melon-headed whale is typically delphinid in shape, with the exception of a very broad rostrum and deep antorbital notches. It is similar to the skull of the common bottlenose dolphin, but the teeth of the melon-headed whale are much smaller and more delicate. The high tooth count of this species separates its skull from those of the other small beakless whales. The melon-headed whale is a member of the subfamily Globicephalinae where it is closely allied with the very similar pygmy killer whale and the larger pilot whales, false killer whales, and Risso's dolphin.