Anomalous colour in Neotropical mammals: a review with new records for Didelphis sp. (Didelphidae, Didelphimorphia) and Arctocephalus australis (Otariidae, Carnivora)

Abstract

Anomalous colourations occur in many tropical vertebrates. However, they are considered rare in wild populations, with very few records for the majority of animal taxa. We report two new cases of anomalous colouration in mammals. Additionally, we compiled all published cases about anomalous pigmentation registered in Neotropical mammals, throughout a comprehensive review of peer reviewed articles between 1950 and 2010. Every record was classified as albinism, leucism, piebaldism or eventually as undetermined pigmentation. As results, we report the new record of a leucistic specimen of opossum (Didelphis sp.) in southern Brazil, as well as a specimen of South American fur seal (Arctocephalus australis) with piebaldism in Uruguay. We also found 31 scientific articles resulting in 23 records of albinism, 12 of leucism, 71 of piebaldism and 92 records classified as undetermined pigmentation. Anomalous colouration is apparently rare in small terrestrial mammals, but it is much more common in cetaceans and michrochiropterans. Out of these 198 records, 149 occurred in cetaceans and 30 in bats. The results related to cetaceans suggest that males and females with anomolous pigmentation are reproductively successful and as a consequence their frequencies are becoming higher in natural populations. In bats, this result can be related to the fact these animals orient themselves primarily through echolocation, and their refuges provide protection against light and predation. It is possible that anomalous colouration occurs more frequently in other Neotropical mammal orders, which were not formally reported. Therefore, we encourage researchers to publish these events in order to better understand this phenomenon that has a significant influence on animal survival.Keywords: albinism, hypopigmentation, leucism, Neotropical mammals, piebaldism.Coloração anômala em mamíferos Neotropicais: uma revisão com novos registros para Didelphis sp. (Didelphidae, Didelphimorphia) e Arctocephalus australis (Otariidae, Carnivora) ResumoColorações anômalas ocorrem em muitos vertebrados tropicais. Entretanto, estas são consideradas raras em populações selvagens, havendo poucos registros para a maioria dos táxons. Reportam-se, neste estudo, dois novos casos de coloração anômala em mamíferos. Além disso, por meio de uma extensa revisão bibliográfica, foram compilados os casos publicados sobre coloração anômala em mamíferos neotropicais entre 1950 e 2010. Cada registro foi classificado como albinismo, leucismo, piebaldismo ou, eventualmente, como coloração indeterminada. Como resultados, reportouse o registro de um espécime leucístico de gambá (Didelphis sp.) no sul do Brasil e de um espécime de lobo-marinho sul-americano (Arctocephalus australis) com piebaldismo no norte do Uruguai. Também foram analisados 31 artigos científicos, resultando em 23 registros de albinismo, 12 de leucismo, 71 de piebaldismo e 92 registros classificados como de pigmentação indeterminada. A coloração anômala aparentemente é rara em pequenos mamíferos terrestres...

First confirmed record of a leucistic Antarctic fur seal pup born outside the Scotia Arc Islands

“…Whilst the exact genes responsible for leucism have not been identified (Fertl & Rosel 2002;Summers 2009;Abreu et al 2013), the mutation is known to be recessive (Hoekstra 2006). The relative genetic (Boyd 1993, Hofmeyr et al 2005b.…”

Occurrence of leucism in Eira barbara (Carnivora, Mustelidae) in Brazil

“…Except for the report of the occurrence in pinniped species (Acevedo & Aguayo 2008;Abreu et al 2013), anomalous colors in other Carnivora is known in Eira barbara (Trolle 2003;Reis et al 2005;Tortato & Althoff 2007), in Nasua narica (Silva-Caballero et al 2014), and in Lontra longicaudis (Arriaga-Flores et al 2016).…”

“…In a recent study, 198 cases of abnormal coloration in 26 Neotropical mammal species was reported (Abreu et al 2013), with cases being much more common in cetaceans, chiropterans and rodents (Pessôa & Reis 1995;Fertl et al 2004;Abreu et al 2013, Neves et al 2014. Except for the report of the occurrence in pinniped species (Acevedo & Aguayo 2008;Abreu et al 2013), anomalous colors in other Carnivora is known in Eira barbara (Trolle 2003;Reis et al 2005;Tortato & Althoff 2007), in Nasua narica (Silva-Caballero et al 2014), and in Lontra longicaudis (Arriaga-Flores et al 2016).…”

Albinismo em zorrilho, Conepatus chinga (Mammalia, Carnivora, Mephitidae). O

“…Albinism is considered a rare event on wild animals, and it has rarely been reported on such creatures (Abreu et al, 2013). It is a natural genetic variation of recessive and mutational order caused by a deficit in melanin production (Walter, 1938).…”