Abnormal pelage color in mantled howler monkey (Alouatta palliata mexicana) in Veracruz, México

El leucismo es una despigmentación total o parcial del pelaje, mientras que el albinismo es la pérdida total de pigmentos en el cuerpo entero; las condiciones anormales de la carencia del pigmento se deben a la expresión de genes recesivos. Se realizó una expedición ad libitum en el Ejido Álvaro Obregón, al suroeste de Nuevo Cantón, municipio de Uxpanapa, Veracruz en diciembre de 2019. Presentamos el primer registro de un individuo de mono aullador de manto (Alouatta palliata mexicana) con coloración no convencional (probablemente leucismo o albinismo), observado en una tropa silvestre en la región del Valle de Uxpanapa, Veracruz, México. La coloración de la mucosa oral y palpebral no muestran pigmentación y pueden ser resultado de la expresión de genes recesivos en el individuo, por lo que realizar estudios más profundos sobre la expresión de genes recesivos ampliaría la comprensión del fenómeno.

Risk factors connected to gastrointestinal parasites in mantled Alouatta palliata mexicana and black howler monkeys Alouatta pigra living in continuous and in fragmented rainforests in Mexico

In this study we document the prevalence of gastrointestinal parasites (helminths and protozoans) found in fecal samples of populations of Alouatta palliata mexicana and of A. pigra in Los Tuxtlas and in Palenque, southeast Mexico, and its relation to habitat condition, sex/age and season. Nineteen parasite morphotypes were detected in the fecal samples from populations of the two howler monkeys, of which 58% were shared by both species. When considering all parasite species, populations of the two howler species were more likely to be parasitized in fragmented habitat compared to continuous habitat. Individuals of both howler monkey species that lived in fragmented habitat had a higher prevalence of Controrchis biliophilus. A. p. mexicana individuals had a higher prevalence of Trypanoxyuris minutus than A. pigra, probably the result of the larger group sizes found in the former species, and T. minutus was more likely to be found in A. palliata individuals that lived in fragmented habitat. Adult A. p. mexicana males had a higher risk of being parasitized compared to adult females, but these differences were not detected in A. pigra. Parasite species such as Entamoeba sp., Nematoda sp. 28, Nematoda sp. B and Parabronema sp. where only found during the wet season in both howler monkey species. Populations of both howler monkey species had a higher prevalence of Nematoda sp. A in the wet season and Ascaridae eggs were only detected during the wet season in A. pigra. Other parasites detected displayed no clear seasonal pattern.