Extensão da zona de contato e potencial hibridação entre Alouatta caraya e Alouatta guariba clamitans na região de São Francisco de Assis, RS

• Autor(a) principal: Silva, Felipe Ennes
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional PUCRS
• Texto Completo: http://hdl.handle.net/10923/5331
• topic: BIOLOGIA; ZOOLOGIA; PRIMATAS; GENÉTICA; MACACOS - RIO GRANDE DO SUL; HIBRIDIZAÇÃO

The occurrence of contact zones of the distribution of Alouatta species and their likely hybridization were recently described for A. palliata and A. pigra in Mexico and A. caraya and A. guariba clamitans in south Brazil and northeast Argentina. The present study focused on determining the extension of one of these contact zones and potential hybridization (Cerro dos Negros) in São Francisco de Assis region, state of Rio Grande do Sul, Brazil. Population surveys were conducted in five sites in the neighborhood of Cerro dos Negros. A total of 108 howler monkey group sightings were obtained during 80 days of field research and 387 km of trails walked. Twelve groups of A. caraya, one containing individuals identified as hybrids on the basis of their mosaic pelage coloration, and 17 groups of A. guariba clamitans, seven containing putatively hybrid individuals, were identified. Five mixed-species groups containing hybrids and four groups composed exclusively by putative hybrids were also seen. The mosaic pelage coloration was seen in adult males, adult females and immature individuals. In sum, 44. 6% of all individuals were identified as pure A. guariba clamitans, 30. 8% as pure A. caraya and 24. 5% as putative hybrids. Despite the fact that allopatric A. caraya forms larger groups than alloptaric A. guariba clamitans, the sighted groups were similar in size, regardless of study site and group membership. The infant to adult female ratio also was similar among all types of groups, allowing to suggest that hybridization is not compromising the reproductive process. Although genetic analyses are required to confirm the hybrid or pure status, as well as the fertility, of the howlers from the surveyed populations, this study showed that the contact zone is wider and that hybridization between sympatric A. caraya and A. guariba clamitans is probably common.