3.3.4.5 Alouatta arctoidea Cabrera, 1940 Type: Adult male, Paris Museum. Type locality: Caracas, Venezuela, fixed by J. A. Allen (1916) on the basis of Humboldt’s vernacular name (Hill 1962), further restricted by Cabrera (1957) to the valley of Aragua (Groves 2001). Common name: Venezuelan red howler, Ursine red howler. Alouatta arctoidea occurs on the island of Trinidad and in northern Venezuela, from the coastal region of Falcón to the state of Miranda (north of the Orinoco) (Fig. 3.1). Bodini and Pérez-Hernández (1987) reported a possibly distinct form in the Venezuelan llanos; however, no further studies have reported the existence of this howler and here we consider it as part of A. arctoidea. This species was initially described by Humboldt and Bonpland (1805) as Simia ursina but he created confusion due to the disagreement between the description and the figure given by the author (which depicted A. guariba). The name ursina (Humboldt) is now considered a synonym of guariba. J. A. Allen (1916) designated this form as a subspecies of A. seniculus (A. s. ursina), and Cabrera (1940) proposed to call it A. s. arctoidea, as the name ursina was inadmissible for this form given that it is a homonym to Simia hamadryas ursinus Kerr, 1792 and Simia ursina (Bechstein 1800) used to refer to the “ursine baboon” (Cabrera 1940). Based on cytogenetic differences recognized by Stanyon et al. (1995), this taxon is currently accepted as a full species. The 14 chromosomal rearrangements found by these authors between A. arctoidea (four individuals from Hato Masaguaral, Venezuela) and A. sara (one individual captured in Bolivia, held at the San Diego Zoo) are more typical of differences between species, and are on the same order of magnitude as those found between A. sara and A. seniculus by Minezawa et al. (1985). However, until now no A. arctoidea specimens have been analyzed using molecular techniques and no monkeys from northern Venezuela have been cytogenetically characterized. Therefore, further validation of this species is necessary and the extent of its distribution range remains to be studied.

Published as part of Cortés-Ortiz, Liliana, Rylands, Anthony B. & Mittermeier, Russell A., 2015, Howlec MonSeys Adaptive Radiation, Systematics, and Mocphology, pp. 49-84 in The Taxonomy of Howler Monkeys: Integrating Old and New Knowledge from Morphological and Genetic Studies, New York Heidelberg Dordrecht London :Springer on pages 75-76, DOI: 10.1007/978-1-4939-1957-4, http://zenodo.org/record/17352914