Link to English Wikipedia entry: Yucatán Black Howler Monkey
Link to German Wikipedia: Guatemala-Brüllaffe
Link to French Wikipedia: Hurleur du Guatemala
Link to EOL.org: Alouatta pigra
Link to iNaturalist.org: Alouatta pigra
Links to my pictures: Yucatán Black Howler Monkey
Binomial Links for Alouatta pigra on guenther-eichhorn.com