Resumen

Extension of the contact zone and probable hybridization between brown howler monkeys (Alouatta guariba clamitans) and black-and-gold howler monkeys (Alouatta caraya) (PRIMATES, ATELIDAE) in southern Brazil. Mastozool. neotrop. [online]. 2015, vol.22, n.2, pp.303-310. ISSN 0327-9383.

Species of howler monkeys (genus Alouatta) generally are parapatric. However, many areas of sympatry between different species of this genus have been recorded in recent years. We report the discovery of a new contact zone and probable hybridization between black-and-gold howler monkeys (Alouatta caraya) and brown howler monkeys (Alouatta guariba clamitans) in São Vicente do Sul, Rio Grande do Sul, Brazil (29° 46’ 07” S; 54° 47’ 53” W). We report two sightings of heterospecific groups of black-and-gold and brown howler monkeys, each composed of eight individuals, including three probable hybrids (two subadult males and one adult female). We also observed monospecific groups of phenotypically pure individuals of both species. The most plausible explanation for the occurrence of this contact zone is that brown howlers may be using the riparian forest of the Ibicuí River and its tributaries as a dispersal route towards areas of the Pampa biome, typically inhabited by black-and-gold howlers.

Palabras clave : Geographic range expansion; Hybrid zone; Mixed groups; Sympatry.

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