Apparent Confirmation that Alouatta villosa (Gray, 1845) is a Senior Synonym of A. pigra Lawrence, 1933 as the Species-Group Name for the Black Howler Monkey of Belize, Guatemala and Mexico

Abstract

The revision of the Mesoamerican howler monkeys by Barbara Lawrence in 1933 (Bull. Mus. Comp. Zool. Harv. 75: 313–354) resulted in the black howler of the Yucatán Peninsula, Mexico, Belize, and northern Guatemala being referred to as Alouatta pigra Lawrence, 1933. In her revision, Lawrence (1933) recognized the existence of a previous name, Mycetes villosus Gray, 1845, for the black howlers of the region, but considered that it was not possible to use it because the holotype (in the Natural History Museum, London) was restricted to a damaged skull of an immature female (the skin had been lost), the type locality was imprecise and confused, and she was unable to determine to which of two forms she named (A. palliata pigra [Mexico and Guatemala] and A. palliata luctuosa [Belize]) it may have belonged. James D. Smith (1970, J. Mammal. 51: 358-369) argued that luctuosa was indistinguishable from pigra, but that pigra should be considered a species distinct from palliata. Here I discuss the type specimen of Mycetes villosus and its probable type locality, and argue, as Prudence Napier did (1976, Catalogue of Primates in the British Museum (Natural History). Part 1: Families Callitrichidae and Cebidae. British Museum [Natural History], London), that Alouatta pigra Lawrence, 1933 is a junior synonym of Alouatta villosa (Gray, 1845).