spadix), and Jentink's duiker (C. jentinki). In 2012, Anne R. Johnston (of the University of Orleans) and colleagues constructed a cladogram of the subfamily Cephalophinae (duiker) based on mitochondrial analysis. They showed that within the "giant duiker" group, the bay duiker formed a clade with Jentink's duiker, and the zebra duiker is sister to this clade. Similarly, Abbott's duiker and the yellow-backed duiker form a clade sister to Sylvicapra. The bay duiker and Jentink's duiker probably evolved during the Pleistocene, less than 2.5 million years ago. Although the species may be monotypic, a 2003 paper identified two subspecies of the bay duiker: C. d. dorsalis (Gray, 1846): western bay duiker, found in western Africa C. d. castaneus {Thomas, 1892): eastern bay duiker, found in central Africa Description The bay duiker is a moderately sized antelope; the typical head-and-body length is . Both sexes reach at the shoulder. The sexes do not vary considerably in their weights either; the typical weight range for this duiker is . Hence, sexual dimorphism in this species is not as remarkable as in other bovids, though females are often larger than males. The tail, black on the outside but white in the inner parts, is long. The tail of the eastern bay duiker terminates in a white tuft. Both sexes possess a pair of spiky horns, measuring . Rowland Ward, however, recorded a maximum horn length of from Yokadouma (Cameroon). The horns of females are generally narrower. Both sexes have a bright reddish-brown coat. The ventral parts and the flanks are all reddish-brown, and the legs dark brown. A notable feature of this duiker is the well-pronounced solid stripe of black extending from the back of the head to the tail. This stripe is narrower in females. Due to its nocturnal nature, the bay duiker has large conspicuous eyes. Whiskers can be observed above the eyes and around the nostrils. The patches of white fur around the whiskers are in sharp contrast to the dark reddish face. Juveniles have a dark coat, that develops the stripes and chestnut to reddish-brown color gradually. The face is marked by a dark region from the nose to the forehead, separated from the rest of the face by two light brown furrows extending above or circling its eyes. Above the eyes and on the lips and chin white spots can be seen. The head has a diminutive crest (a