Evolutionary inferences on the diversity of the genus Aotus (Platyrrhini, Cebidae) from mitochondrial cytochrome c oxidase subunit II gene sequences

Abstract

abstract 2009 Elsevier Inc. All rights reserved. 1. IntroductionThe nocturnal owl monkeys, Aotus spp. (Infraorder Platyrrhini),are distributed in the Neotropics from southern Panama to North-ern Argentina (Fig. 1), although they are absent from Brazil’s Atlan-tic Forest (Hershkovitz, 1983). Despite its relative lack ofmorphological variation in comparison with other platyrrhine gen-era, Aotus has proven to be one of the most difficult to interpret inphylogenetic terms. There is still no clear consensus on the posi-tion of the genus within the Platyrrhini (e.g., Kay, 1990; Schneideret al., 2001; Steiper and Ruvolo, 2003; Rosenberger and Tejedor, inpress), and there is at least as much controversy over the numberof owl monkey species.Aotus was originally considered to be a monotypic genus with asingle species, Aotus trivirgatus (Hershkovitz, 1949). However,Brumback et al. (1971) identified considerable karyotypic varia-tion, which led to the proposal of a number of new species (Brum-back, 1974; Thorington and Vorek, 1976). At least 18 distinctkaryotypes are now known, with 2n varying between 46 and 58(Ma et al., 1976, 1985; Galbreath, 1983; Pieczarka et al., 1993; Tor-res et al., 1998).Following these initial cytogenetic discoveries, Hershkovitz(1983) revised the genus based on genetic, morphometric, andzoogeographic parameters, and proposed a scheme encompass-ing nine species and four subspecies, arranged in two maingroups, based on the coloration of the pelage on the sides ofthe neck. The ‘‘gray-necked” group is distributed north of theAmazon, whereas the ‘‘red-necked” group occurs south of thisriver (Fig. 1).Hershkovitz’s (1983) scheme was challenged by subsequentstudies based on cytogenetics (e.g., Pieczarka et al., 1993; Defleret al., 2001), morphology (Ford, 1994; Defler et al., 2001), andmolecular data (Ashley and Vaughn, 1995). Ford (1994), for exam-ple, realigned the forms into just five species. In the first molecularstudy of the genus, Ashley and Vaughn (1995) used the nucleotidesequences of subunit II of the cytochrome c oxidase (COII) enzymefrom three of Hershkovitz’s taxa (Aotus lemurinus griseimembra, Ao-tus nancymai, and Aotus azarae boliviensis), and observed highlydivergent values, with a phylogenetic tree which contradictedthe gray/red-neck dichotomy.As all present-day platyrrhines are the result of a quite re-cent, Early Miocene diversification (Goodman et al., 1998;Schneider et al., 2001; Steiper and Ruvolo, 2003; Opazo et al.,2006; Poux et al., 2006), COII gene sequences have proven usefulfor the interpretation of both intra- and intergeneric relation-ships (Figueiredo et al., 1998; Collins and Dubach, 2000a, b; Asc-unce et al., 2002; Sena et al., 2002; Nieves et al., 2005). In thepresent study, the phylogenetic relationships among seven ofHershkovitz’s (1983) Aotus taxa were evaluated using COII genesequences, constituting a more robust sample than Ashley andVaughn (1995) study.