Alouatta macconnelli Elliot, 1910

3.3.4.6 Alouatta macconnelli Elliot, 1910 View in CoL

Type: Adult male, skin and skull, No. 1908.3.7.3 , British Museum (Natural History) ( Napier 1976).

Type locality: Coast of Demerara, Guiana.

Common name: Guianan red howler, Golden howler.

Alouatta macconnelli is distributed throughout the Guiana Shield, including French Guiana, Suriname and Guyana, southern Venezuela (south of the Río Orinoco), and northern Brazil (from the coast of the state of Amapá to the eastern margins of the rios Negro and Branco, including Gurupá island in the Amazon delta) ( Fig. 3.1 View Fig ).

There has been confusion about the name that should be used for the howler monkeys that inhabit the Guiana Shield, as well as whether one or two taxa should be recognized. The confusion started with É. Geoffroy Saint-Hilaire’s (1812) description of Stentor stramineus , 1 which was based on a specimen of a female A. caraya from Central Brazil ( Elliot 1913; Rylands and Brandon-Jones 1998; Gregorin 2006). Later, Elliot (1910) described A. macconnelli from one specimen from French Guiana, and synonymized stramineus with A. seniculus ( Elliot 1913) , which he deemed as clearly different from A. macconnelli . Tate (1939) considered both macconnelli and stramineus as subspecies of A. seniculus , and da Cruz Lima (1945) considered A. macconnelli ( Elliot 1910) a synonym of A. seniculus straminea ( Geoffroy Saint-Hilaire 1812) . Hill (1962) still included both straminea and macconnelli as subspecies of A. seniculus , but wrote “There is every indication that both macconnelli and amazonica fall within the range of variation of stramineus and they should accordingly be treated as synonyms thereof, an action already taken by Cabrera (1957).”

Bonvicino et al. (1995), based on morphological analyses of individuals in the range of the two putative subspecies ( A. s. stramineus and A. s. macconnelli ), concluded that the howlers from the northern bank of the Amazon can be divided into two species separated by the Rio Trombetas, and argued that this is supported by the biochemical and karyological analyses of Sampaio et al. (1991) and Lima et al. (1990) and Lima and Seuánez (1991), respectively. However, as discussed by Rylands and Brandon-Jones (1998, p. 887), the main “confusion regarding the identity of the Guianan howler is compounded by the inadequate, or imprecise information and uncorroborated conjectures about its geographic distribution.” Rylands and Brandon-Jones (1998) found that the same specimens analyzed by different authors as part of one taxon were regarded as the alternative taxon by others. This is true throughout the taxonomic history of these two taxa, but was particularly true in the case of the analyses done by Bonvicino et al. (1995).

Molecular analyses by Sampaio et al. (1996) using biochemical data concluded that the genetic distance between populations from opposite sides of the Rio Trombetas, and those to the east of the Rio Jari are too small to justify their separation even at the subspecific level. Figueiredo et al. (1998) analyzed mitochondrial DNA sequence data of individuals from the same locations as those of Sampaio et al. (1996) and found that genetic distances among them were small and similar to those found among populations, and that individuals from different localities were sometimes less divergent than individuals from the same population. They concluded that both biochemical and mitochondrial DNA data strongly suggested gene flow among the three studied populations and the existence of a single species within the studied area.

Gregorin (2006) studied pelage coloration and morphometric data from specimens sampled in Brazil, and compared them to specimens from the rest of the Guiana Shield (French Guiana, Suriname, and southern Venezuela). He found that the Brazilian and “Guianan” specimens presented great variation in pelage coloration, which was not distinguished geographically. The same was true when analyzing the morphology of the hyoid bone. Principal Component Analyses of morphometric data also did not support the recognition of two taxa for the Guiana Shield ( Gregorin2006). In all, Gregorin’s study supported Figueiredo et al.’s (1998) conclusion that there is a single taxon of howler in the Guiana Shield, which is easily distinguishable from the other recognized species of howlers. The description of Elliot’s A. macconnelli type falls within the spectrum of variation found in the specimens from the Guiana Shield by Gregorin (2006), and he concluded that this taxon should be conservatively named A. macconnelli , but acknowledged the observation by Rylands and Brandon-Jones (1998) that given that the type locality of Mycetes auratus Gray is in the west of the range of A. macconnelli , the correct name for this species may well be Alouatta auratus (Gray, 1845) .