Notes of hypopigmentation in mantled howler monkeys Alouatta palliata
(Gray 1849): First documented cases of whole-body leucism from a
critically endangered ecosystem in South America
Abstract
The existence of hypopigmentation such as leucism is the result of
inbreeding in isolated populations of wildlife and it is associated with
environmental stressors. This anomaly may reduce survival rates. Leucism
has been record in wildlife, but overall, it is considered very rare.
There have been few records of mantled howler monkeys with leucism in
Mexico and Costa Rica, but whole-body leucism in howler monkeys from
South America was unknown. In this article, we report for the first-time
documented cases of whole-body leucism in young individuals of mantled
howler monkeys Alouatta palliata in an isolated remanent of
tropical dry forest in southwestern Ecuador known as Cerro Blanco
Protective Forest. In total, we found two individuals: a juvenile female
and a juvenile male in October 2021. We also include a short report
about the observation of two seedlings of Dichapetalum (Dichapetalaceae)
showing albinism. The report of howler monkeys with whole-body leucism
may be caused by the interaction of two processes: inbreeding because of
isolated populations and air pollution with sulphur. Thus, immediate
management strategies must be considered to significantly increase
connectivity with other populations of howler monkeys and reduce air
pollution in Guayaquil. Our findings also reveal that hypopigmentation
is becoming more frequent in howler monkey´s population along its
distributional range. Therefore, we encourage the community to consider
a regional management strategy.