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

Penile shape discriminates two cryptic species of Akodon Meyen, 1833 (Mammalia, Rodentia, Cricetidae) from eastern Brazil

Glans penis morphology has been used as a powerful tool in mammal taxonomy to differentiate cryptic species. Neotropical rodent species Akodoncursor and A.montensis are cryptic, and interspecific hybrids are like their parental species. We investigated non-metric and metric phallic characters aiming to differentiate A.cursor from A.montensis. We also evaluated the parental species' influence of the phallic characters on hybrids. We analysed 96 male adults-56 A.cursor, 27 A.montensis, and 13 hybrids, subgrouping species by locality and hybrids by parental species (paternal vs maternal). We verified that A.cursor and A.montensis are distinguishable by penile-shape morphology: A.cursor has an elongated penile form with a flare in the distal portion and A.montensis has a barrel-shaped form. Also, dark spots in ventral view, if present in A.montensis, distinguish A.montensis from A.cursor. Although the non-metric characters differentiate the species, they do not distinguish the subgroups of A.cursor, A.montensis, and hybrids. The metric phallic characters indicated a significant difference between species and hybrids. These characters also differentiate the population groups of A.cursor. However, A.montensis subgroups and hybrids subgroups did not present a significant difference. This study shows the importance of penis morphology in the taxonomy of the cryptic rodent species A.cursor and A.montensis, representing a powerful tool to discriminate male specimens in mammal collections without karyotyping or sequencing, even though the specimens occurred in sympatric areas. Since most taxidermy protocols do not preserve the penis in mammal preparations, liquid preservation of some specimens or the removal of the penis before taxidermy for liquid preservation could be beneficial. We also recommend the organisation in museum collections of a penis bank for the A.cursor species group (or even all rodent species) to avoid losing this important information for species identification.

First records of albinism and leucism in Ctenodactylus gundi (Rodentia: Ctenodactylidae)

Albinism and leucism are genetic disorders that cause atypical coloration. Herein, we present observation cases of hypomelanism not previously recorded in the literature for a Ctenodactylidae species. We report two observations of an albino and a leucistic specimens from two separate locations distant of 230 km in the central and southern Tunisia. The first observation was in Metlaoui (34°21′14.9″N 8°22′16.7″E) and the second in Ghomrassen (33°04′46.5″N 10°21′23.7″E). Certain factors can increase the chances of these atypical colorations in the natural population, but these phenotypes remain rare in rodents, especially in African species.

Registro de desorden cromático en Trachops cirrhosus (Spix, 1823) (Chiroptera: Phyllostomidae) en la Amazonia del Ecuador

Presentamos un caso de desorden cromático observado en un ejemplar de Trachops cirrhosus proveniente de bosques de tierras bajas de la Amazonía ecuatoriana. Durante el trabajo de campo, seis individuos de esta especie fueron capturados con redes de niebla en un hábitat intervenido, de los cuales, un ejemplar macho juvenil fue distinguible del resto de individuos debido a la presencia manchas blanquecinas en la región ventral, en el pecho y abdomen. Discutimos sobre los reportes previos de este tipo de trastornos pigmentarios en murciélagos de Ecuador, y en el Neotrópico, documentando el primer registro de esta especie con esta condición para el país.

Anomalous pigmentation in American primates: review and first record of a leucistic black howler monkey in southeast Mexico

Leucism is an aberration of color that occurs in individuals as a consequence of genetic mutations. Along with albinism and piebaldism, leucism is one of the most commonly reported types of chromatic anomalies in mammals, however, detailed descriptions of such conditions are rare. We report the first record of a leucistic black howler monkey (Alouatta pigra) in southern Mexico, an apparently healthy individual who was the male of a typical black howler group. Additionally, we compiled records of anomalous pigmentation in American primates published in peer-reviewed journals between 1960 and 2021, as well as social media posts regarding casual observations of individuals with such conditions. We found 11 scientific articles which described 13 records of anomalous pigmentation in a total of 44 individuals, from five species, three subspecies and one hybrid. Leucism was the most widely reported condition with six records. We discovered 19 online posts of 20 individuals with anomalous pigmentation, which included two species not reported in scientific literature. Our results suggest that anomalous coloration is not a significant threat to survival, but its occurrence raises interesting, and possibly alarming, questions about the causes of such conditions. We encourage researchers and civil society to formally report such observations of animals with color aberrations, to expand upon the understanding of this phenomenon and to get involved in the conservation of tropical forests.

First Italian record for a partial Isabelline colouration in a European mole, Talpa europaea

The European mole Talpa europaea Linnaeus, 1758 is a quite common species in Central Italy. I report the first Isabelline individual of this species recorded in the scientific literature. Actually, this species is quite widespread throughout Europe, but coat-colouration anomalies have never been described in Italian mole populations. Further research is therefore needed to determine the percentage of occurrence of anomalous individuals and the evolutionary history of coat anomalies in moles.

Camera trap records of leucistic Eurasian badgers (Meles meles) in central Norway

Coat coloration plays an important role in communication, camouflage, and sexual selection in animals. Genetic mutations can lead to anomalous colorations such as melanism and leucism, where animals appear, respectively, darker or lighter than normal. Reporting abnormal coloration in wild animals is an important first step to understand the distribution, prevalence, and potential fitness consequences of these rare events. Here, we report several records of suspected leucism in the Eurasian badger (Meles meles) in a population in central Norway. Several camera traps recorded at least two leucistic individuals between 2017 and 2020. It took considerable effort, almost 400,000 camera trap nights over a period of 10 years all over Norway, to obtain a total of eleven records of leucistic badgers, indicating the rarity of this phenotype. It is unclear what has caused the presence of multiple leucistic badgers in a single population, but recent colonization and lack of predators might have played a role. Due to our observations, future studies can now be developed to study the underlying mechanisms and potential consequences of leucism in this badger population. The increasing use of networks of camera traps in wildlife research will provide new opportunities to record rare coloration in wild animals.

Prevalence of Varied Coat Coloration in a Yellow-Throated Marten (Martes flavigula) Population

Simple Summary

Abnormal coloration is very rare in any given population of wildlife; however, our research identified a yellow-throated marten population with a high ratio of this phenomenon for the first time. Across the main distribution of the species with relevant observational data, we observed abnormally-colored martens in only Northeast Tiger and Leopard National Park. Abnormal coloration had a variety of forms and individuals with white paws that accounted for a larger proportion of the overall population than normal individuals. This shows heritable variation in the region, which is worthy of further research.

Abstract

Mammalian coat color is determined by heritable variations such as disease, nutrition, and hormone levels. Variation in animal coat color is also considered an environmental indicator and provides clues for the study of population genetics and biogeography. Records of abnormal coloration in the wild are rare, not only because it is often selected against, but also because of the difficulties in detection of the phenomenon. We used long-term camera-trapping data to first report abnormal coat coloration in yellow-throated marten (Martes flavigula) in China. Six types of abnormal coloration were found only in the Northeast Tiger and Leopard National Park, Northeast China, which were not reported in other regions in China. A total of 268 videos of Martes flavigula contained normal coloration, 455 videos of individuals of the species contained abnormal coloration, 437 contained the ‘gloving’ type (martens with de-pigmented front toes, paws or lower forelimbs), while the remaining other 18 videos contained five types (different degrees of white-spotting and dilution). The higher relative abundance index (0.428, ‘gloving’ to 0.329, normal) and wide distribution area of the ‘gloving’ type indicated that this abnormal coat coloration type is usual in Northeast China, which may reflect genetic variability in the local population. These records will contribute to further research on animal coat color and its corresponding adaptive strategy.

Albinism in a raccoon Procyon lotor from Mexico

Albinism is defined as the complete absence of pigment in skin, hair, and eyes directly caused by a hereditary disorder in the production of melanin. This genetic abnormality is usually attributed to environmental factors such as low quality of habitat and inbreeding. In this note, we recorded a case of partial albinism in a raccoon (Procyon lotor) captured by poachers in the area known as Barranca de Matlacobatl, Municipality of Teocelo, Veracruz, Mexico. The specimen was recovered by the civil association Pro-Vida Silvestre Teocelotl and sheltered for a week under medical care. This is the second record in Mexico of a wild albino raccoon. Specifically, it was recorded particularly for a neotropical region of the center of the state of Veracruz, Mexico.

First observation of a chimpanzee with albinism in the wild: Social interactions and subsequent infanticide

Albinism—the congenital absence of pigmentation—is a very rare phenomenon in animals due to the significant costs to fitness of this condition. Both humans and non‐human individuals with albinism face a number of challenges, such as reduced vision, increased exposure to ultraviolet radiation, or compromised crypticity resulting in an elevated vulnerability to predation. However, while observations of social interactions involving individuals with albinism have been observed in wild non‐primate animals, such interactions have not been described in detail in non‐human primates (hereafter, primates). Here, we report, to our knowledge, the first sighting of an infant with albinism in wild chimpanzees (Pan troglodytes schweinfurthii), including social interactions between the infant, its mother, and group members. We also describe the subsequent killing of the infant by conspecifics as well as their behavior towards the corpse following the infanticide. Finally, we discuss our observations in relation to our understanding of chimpanzee behavior or attitudes towards individuals with very conspicuous appearances.

Observations of wild non‐human primates with albinism are extremely rare

We report the first observation of a chimpanzee with albinism in the wild

We describe interactions between the infant with albinism and other group members

We describe the subsequent infanticide of the individual with albinism

We discuss these observations in light of our understanding of chimpanzee behavior

Albinism in Brazilian common opossums (Didelphis aurita)

Albinism has been sporadically recorded in Virginia opossums (Didelphis virginiana) in the United States and Mexico, but records of pigmentation disorders in other Didelphis spp. are rare. The Brazilian common opossum (Didelphis aurita) is a cat-sized nocturnal omnivorous marsupial that inhabits Atlantic and Araucaria forests in South America. A litter of five young Brazilian common opossums was rescued at Espírito Santo state, southeast Brazil, of which two were albinos (one male, one female) and the remaining had normal pigmentation (three males). The two albinos had a complete lack of integumentary and retinal pigmentation, representing the first recorded cases of albinism in this species (and the first record in a Didelphis sp. other than the Virginia opossum).

Primeros registros de leucismo en la ardilla de nuca blanca Simosciurus nebouxii (Rodentia: Sciuridae) en la ciudad de Lima, Perú

El leucismo es una anomalía cromática que se presenta en una amplia variedad de mamíferos y otros vertebrados, aunque de manera poco frecuente. Los reportes de ardillas arborícolas con esta condición se han hecho en especies de Asia, Norteamérica y Europa, pero para especies de ardillas neotropicales son casi inexistentes. Esta nota reporta la ocurrencia de leucismo en ardillas de nuca blanca que habitan las áreas verdes de tres distritos de la ciudad de Lima, siendo necesarios futuros estudios genéticos y poblacionales para determinar su causa.

Apparent piebald variants in quolls (Dasyurus): examples of three recent cases in the spotted-tailed quoll Dasyurus maculatus

Pelage patterning plays an important role in animal behaviour. Variation in pelage patterns can change with pigment distribution and quantity in individuals. We present three cases of apparent piebaldism – a condition where the body is patchily unpigmented – in the spotted-tailed quoll Dasyurus maculatus. Using a comprehensive dataset of historical descriptions (from Dunlop et al. 2020), we conclude that these cases represent the first description of this phenotype in the genus Dasyurus, but acknowledge capture and testing of these individuals is required to be certain of the cause. Little is known about the implications of pelage patterning in quoll species and further investigation is required to understand the evolutionary and functional role of unaffected and unpigmented variants.

Primer registro de leucismo en el género Coendou Lacépède, 1799 (Rodentia: Erethizontidae)

Se reporta por primera vez un caso de leucismo en la especie Coendou prehensilis. El individuo fue hallado de forma fortuita en una zona de bosque perturbado en la región de Los Andes en Venezuela.

First record of albinism in spiny rats of genus Proechimys (Rodentia: Echimyidae) from Western Amazon

Albinism is a rare condition in natural populations. One of the factors that would lead to higher allele frequency for the albino phenotype is bottleneck events, causing small population sizes and loss of genetic diversity. Here, we report the first record of albinism in one specimen of Proechimys gardneri from Porto Velho, Rondônia, Brazil. This is also the first record of albinism for the genus and for the family Echimyidae. We identified the specimen through morphology and confirmed the identification by 801 base pairs (bp) of mitochondrial marker cytochrome b (Cyt b). We also discuss the selection against albino phenotype in natural populations.

Morphological study of larynx, trachea, and lungs of Didelphis marsupialis (LINNAEUS, 1758)

Background and Aim:

From a biomedical point of view, the value of marsupials as a model of primitive mammals is indisputable. Among its species, the possum is a model that allows the study of the ontogeny of different organic systems, as well as their physiological aspects. The relevance of anatomical, functional, evolutionary, and phylogenetic study of marsupials for the development of comparative morphology is extensively documented in the literature. However, there are still many aspects to be further evaluated, as the anatomy and histology of the respiratory tract of this species. The aim of this study was to describe the morphology of the larynx, trachea, and lungs of Didelphis marsupialis.

Materials and Methods:

Five adult male animals were donated to the Comparative Animal Anatomy Laboratory – LAAC/CCAA-UFMA, for morphological studies. Specimens were washed in running water to perform biometrics. Then, they were fixed with 10% formaldehyde solution. After the fixation period, the specimens were positioned in dorsal decubitus position, for dissection of the respiratory system organs, by opening the ventral region of the neck and thoracic cavity, with subsequent removal of the pectoral muscles, ribs, and sternum. For histological analysis, fragments of 1 cm² of the larynx (epiglottis and thyroid cartilages), trachea, and lungs were collected and fixed in 10% formaldehyde solution. Right after fixation, the fragments were dehydrated in increasing concentrations of ethyl alcohol (70, 80, 95, and 100%), diaphanized in xylene, embedded in paraffin, and sectioned into thin slices of 5 μm using a microtome. Sections were stained using the hematoxylin and eosin technique.

Results:

Anatomically, the larynx starts right after the pharynx. It consisted of four cartilages: Epiglottis, cricoid, thyroid, and arytenoid. The trachea was made of dorsally incomplete cartilaginous rings. At the entrance of the thoracic cavity, it bifurcated into the left and right main bronchus. The left lung was smaller than the right lung, with two lobes (cranial and caudal). The right lung presents the cranial, middle, caudal, and accessory lobes. Histologically, the epiglottis consisted of elastic cartilage and is covered by a non-keratinized stratified squamous epithelium. Thyroid cartilage is made of hyaline cartilage covered by smooth muscle. The trachea presents hyaline cartilage, with ciliated pseudo-stratified epithelium, serous glands, isogenic groups of chondrocytes, and perichondrium. The lung consisted of bronchi, bronchioles, and alveoli, also presenting blood vessels and arteries.

Conclusion:

Morphologically, the larynx, trachea, and lungs of D. marsupialis were similar to those of the other Didelphids described in the literature.

First record of albinism in the paca Cuniculus paca (Rodentia, Cuniculidae) in southeast Mexico

Even though there have been reports of anomalies in the colouration of several species of neotropical mammals, these events are considered to be rare within natural populations. Here we report the first case of albinism in the paca (Cuniculus paca). During the months of June and July 2017, we obtained several images of an adult albino male using camera traps in the region of Sierra Norte in Oaxaca, in the southeast of Mexico, in a medium subdeciduous forest.

First record of albino lowland tapirs (Tapirus terrestris Linnaeus 1758) in an important Brazilian Atlantic Forest hotspot

Albinism is the absence of pigmentation or coloration and is rarely found in nature. In this study we examined photos and videos obtained by cameras traps in the Legado das Águas Reserve. In the images, we identified two albino lowland tapirs. The results highlight the necessity of understanding the genetic diversity of lowland tapir populations and the important role of the professional photography associated with scientific research.

Data on First Record of Brown Morph Banded Langur (Presbytis femoralis), Leucistic Dusky Leaf Monkey (Trachypithecus obscurus) in Malaysia and Review of Morph Diversity in Langur (Colobinae)

Morphism refer to polymorphic species, in which multiple colour variants coexist within a population. Morphism in primates is common and langurs also exhibit certain characteristics of morphism, such as conspicuous natal coats. Banded langurs (Presbytis femoralis) and dusky leaf monkey (Trachypithecus obscurus) exhibits the same characteristics of conspicuous natal coats, but these coats are only limited to infants and changed when they reached adulthood. This article reports the first discovery of rare brown morph of two adult male banded langurs and one leucistic adult female dusky leaf monkey in Malaysia. We also conducted a systematic literature search to review the diversity of morphism in leaf monkey globally.

Leucismo em jacaretinga: relato de caso

RESUMO Dentre os crocodilianos com ocorrência no Brasil, o Caiman crocodilus (Linnaeus, 1758) é a espécie de maior frequência, porém sua presença em estudos científicos restringe-se a levantamentos faunísticos, na maioria das vezes. O leucismo, também conhecido como albinismo parcial, é uma anomalia cromática ainda pouco conhecida. Indivíduos portadores dos genes que condicionam a doença apresentam ausência de pigmentação em uma parte ou em todo o corpo, porém os olhos não apresentam alteração. O objetivo deste trabalho foi realizar o primeiro registro de Caiman crocodilus com leucismo no mundo.

Un caso de leucismo parcial en la ardilla de cola roja Notosciurus granatensis (Rodentia: Sciuridae) en el Sur-oeste de Ecuador

La presente nota da a conocer un caso de leucismo parcial en Notosciurus granatensis. El individuo fue avistado en la provincia de El Oro, cantón Pasaje, sector La Loma. El 7 de octubre de 2017, a las 12h44, se observó, entre un remanente de bosque tropical y un cultivo de cacao, presentaba hipopigmentación en la parte terminal de la cola. Si bien se desconoce la razón de su causa, se discuten posibles razones.

Albinism in Didelphis virginiana (Kerr, 1792): the first reported case in Mexico

Atypical colorations occur in different groups of vertebrates. The loss of melanin in the skin, hair and eyes is the result of an autosomal recessive genetic entity. It causes individuals to present with a white coloration of the skin and hair, as well as red eyes, known as albino. This manuscript documents the first record in Mexico of complete albinism in a marsupial, Didelphis virginiana, captured in the Yucatan peninsula.

Beyond the color: the implications of pigmentation polymorphism in the activity behavior of a Neotropical squirrel

Pigmentation polymorphism occurs in many mammals but is considered rare in natural populations. Here, we report the first record of pigmentation polymorphism in a Neotropical squirrel, Guerlinguetus ingrami, at a private reserve in southern Brazil. The number of records for leucistic squirrels was approximately half that for brown squirrels. We also tested the differences in activity patterns between the leucistic and the brown squirrels. Both phenotypes were diurnal, but there was temporal segregation between the two. Further studies are needed to elucidate the occurrence of leucism in G. ingrami, and the possible ecological and behavioral outcomes.

First record of pigmentation disorder in the Fringe-lipped Bat Trachops cirrhosus (Spix, 1823) (Chiroptera: Phyllostomidae) from southeast Brazil

Piebaldism is a genetic pigmentation disorder, which is caused by absence of melanocytes in parts of the skin and/or hair follicles, with eyes and claws normally pigmented. The occurrence of piebaldism in natural populations is rare and the effects on fitness are still unknown. This article reports the first case of pigmentation disorders in the Fringe-lipped Bat Trachopscirrhosus (Spix, 1823) (Chiroptera: Phyllostomidae) caught in Barra do Triunfo, city of João Neiva, northeastern state of Espírito Santo, southeast Brazil.

First record of atypical pigmentation pattern in fin whale Balaenoptera physalus in the Atlantic Ocean

Atypical pigmentation, which is rarely observed in the wild, may influence social interactions between animals and can be detrimental for survival. Hypopigmentation, which is the lack of pigment in a part or on the entire body, is a type of atypical pigmentation pattern that can be either acquired (e.g. vitiligo) or congenital resulting from the inheritance of mutations in pigment-related genes (e.g. albinism, leucism and piebaldism). This study documents atypical pigmentation in a fin whale Balaenoptera physalus off the northwestern coast of the Iberian Peninsula (Atlantic Ocean). Photographic and video data collected between 2016 and 2017 on 30 individual fin whales were examined. One fully-grown fin whale exhibited hypopigmentation. Several white patches of different shapes and sizes were present across the body of the fin whale including on the head, body, dorsal fin, flippers, and flukes. The position, shape, and lack of inflammation of the white patches on the whale observed, along with its body length and condition, might indicate that the depigmentation pattern is due to vitiligo. To our knowledge, this is the first case of atypical pigmentation pattern in fin whales described with photographs and video records. As these observations are rare, especially in highly migratory, long-lived, marine mammal species, this study provides valuable information to better understand the occurrence of this phenomenon. Further studies are needed to determine the ecological and physiological implications of atypical colourations, which might have a significant influence on the animal's survival.

High Incidence of Hypopigmented Marks in the Endangered Florida Bonneted Bat

Aberrant patches of white skin or fur known as hypopigmented marks have been observed in many mammal species worldwide, but they are typically limited to only a few individuals in a population. Hypopigmented marks were documented in only two museum specimens of the federally endangered Florida bonneted bat (Eumops floridanus) as early as 1950, but recent observations suggest that these marks may be more common in this species than previously believed. To better understand the occurrence and persistence of hypopigmented marks in Florida bonneted bats, we evaluated the variation in frequency, compared effects on survival, and assessed spatial and temporal differences of specimens at an intensively studied site and across the species range. From 2014 through 2017, we regularly captured Florida bonneted bats for demographic studies at Babcock–Webb Wildlife Management Area in Charlotte County and we observed hypopigmented marks on 172 (80.8%) of 213 individuals, the highest incidence known for bats. The proportion of hypopigmented marks did not differ with sex, age at first capture, or reproductive status, and importantly, we documented the persistence of hypopigmented marks in individuals over multiple months. We also found no difference in survival or capture probability between hypopigmented and solid-colored individuals. Using data from concurrent mist-net studies, we assessed the proportion of Florida bonneted bats with hypopigmented marks across the species range and found a higher proportion of individuals with hypopigmented marks in the two northern counties (80.8% in Charlotte County and 61.5% in Polk County) compared with the two southern counties (21.1% in Miami–Dade County and 16.7% in Collier County). Additionally, we compared the proportion of hypopigmented individuals in Miami–Dade County between recently captured/collected bats (post-2004) and historically (pre-1965) collected museum specimens and found more hypopigmented marks in recently captured bats. The persistence of hypopigmented marks over time, the presence of marks on bats from different locations, and our finding of no effect of age on the presence of marks all strongly suggest that the hypopigmented marks in Florida bonneted bats are the result of genetic rather than environmental factors. Further study is required to understand the mechanism underlying the high incidence of hypopigmented marks and to determine whether the prevalence of hypopigmented marks indicates low genetic diversity that could threaten Florida bonneted bats.

First record of albinism for the doglike bat, Peropteryx kappleri Peters, 1867 (Chiroptera, Emballonuridae)

Albinism is a type of deficient in melanin production could be the result of genetic anomalies that are manifest as the absence of coloration of part or the entire body of an organism. This type of chromatic disorder can affect several vertebrate species, but is rarely found in nature. Among bats, more than 450 cases of total or partial loss of body pigmentation have been reported. Herein we provide the first report of albinism for the bat species Peropteryxkappleri (Chiroptera: Emballonuridae) with two such specimens being observed from iron formation caves in a conservation unit “Floresta Nacional de Carajás”, Amazon forest, northern of Brazil.

Occurrence of tayras (Eira barbara Linnaeus, 1758) with anomalous coloration in Cerrado remnants in the state of São Paulo, Brazil

Abstract: Coloration anomalies are mainly genetically-based disorders in which body pigmentation is either reduced (hypopigmentation) or produced in excess (melanism), in parts or the totality of the body. Cases of hypopigmentation have been documented in many neotropical mammals, including the tayra (Eira barbara Linnaeus, 1758). We expand the account of anomalous coloration occurrence presenting new registers of hypopigmented tayras in Brazil. Data was collected during a mammal survey carried out in three agricultural landscapes within the Cerrado domain in the northeast of the state of São Paulo. We obtained two kinds of records of hypopigmented tayras, one from direct sighting and the other from a camera-trap. We discuss the likely implications of this conspicuous coloration to tayras and highlight some possibilities of study.

Frequency of leucism in a colony of Anoura geoffroyi (Chiroptera: Phyllostomidae) roosting in a ferruginous cave in Brazil

Abstract: We provide the first report of the frequency of leucism for a species of Neotropical bat. Leucism is an anomaly of the skin pigmentation of an animal that manifests itself as the total or partial loss of the natural color of the species, and can affect part of or the entire body. During a study involving capture and marking individuals of a population of A. geoffroyi residing in a cave in the Brazilian state of Minas Gerais, seven individuals with some degree of depigmentation were recorded out of 616 individuals marked, for a frequency of 1.1%. Since leucism is due to recessive gene expression, these findings may indicate that the population is isolated and possesses a high level of endogamy. Factors that may be responsible for this condition in the studied population remain unknown.

Complete albinism in Oxymycterus dasytrichus (Schinz 1821) (Rodentia: Cricetidae)

Reports of albinism are available for several groups of mammals, including the secondmost diverse family of Rodentia, Cricetidae. Nonetheless, in South America, where cricetid rodents are the most representative of the small mammals, both in richness and abundance, few records of albinism exist. Here, we document the first case of albinism for the cricetid Oxymicterus dasytrichus, and compare the skin, hair and skull morphology of the albino with specimens of the regular coat color pattern of O. dasytrichus collected in the state of Minas Gerais, where the albino specimen was collected. Despite the marked external morphological differences observed in the hair and skin colors, cranial measurements indicate that no salient differences can be observed when comparing particular measures for the skulls of albino and non-albino specimens, neither through a multivariate statistical analysis. We also briefly discuss the relative rarity of complete albinism in Neotropical rodents.

Leucismo parcial en dos especies de Carollia (Chiroptera: Phyllostomidae) en Costa Rica

El 29 de mayo de 2003 a las 18h45 un macho de Carollia sowelli fue capturado en el Parque Nacional Tortuguero (10°25ʼ24ˮN, 83°29ʼ48ˮW) que tenía el extremo del ala derecha de color blanco (aproximadamente la mitad del área de la membrana entre los dedos III y IV). No se pudo tomar fotografías de este individuo antes de liberarlo. El 20 de abril de 2017 a las 20h58 fue capturada una hembra de Carollia perspicillata con manchas blancas en el Parque Nacional Barbilla (9°56ʼ31ˮN, 83°25ʼ12ˮW; Figura 1). Las manchas más prominentes se encontraron bajo la oreja izquierda y el hombro derecho. Otras manchas menos notorias fueron encontradas atrás de la oreja derecha y cerca de la axila izquierda.

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

Abstract The occurrence of anomalous coloration (albinism, leucism and melanism) in mammals is a rare phenomenon in nature, but this phenomenon has been reported for several species of mammals. In this study, we report on the occurrence of leucism in Eira barbara by examining three road-killed individuals and two sightings of live animals in Reserva Particular do Patrimônio Natural Santuário do Caraça, southeastern Brazil. In addition, we examined tayra specimens housed in mammal collections from Brazil and USA. The animals found dead and those sighted had a whitish yellow fur on the body and head, resulting in lighter coloration than the coloring pattern commonly observed in tayras. Despite these lighter color pattern, the specimens showed parts of soft tissue, such as iris and the skin, with pigmentation very similar to that present in individuals with the typical color pattern. This set of factors indicates the specimens recorded were in fact leucistic and not albino. Among the specimens examined in the scientific collections, we found nine individuals from different localities that presented the whitish yellow color pattern. Some studies attribute the higher frequency of cases of leucism due to small populations and / or with some mechanism of reproductive isolation. Thus, analysis of the genetic variability of populations containing individuals with such characteristics should be considered. On the other hand, the occurrence of polymorphic color phenotype in tayras indicates that hypotheses related to the fixation of recessive characteristics, or on possible environmental adaptive advantages of these phenotypes can be tested.

New records of hypopigmentation in two neotropical phyllostomid bat species with different roosting habits (Uroderma bilobatum, Glossophaga soricina)

Hypopigmentation disorders were reported in several bat species roosting in dark and sheltered roosts, but comparable records from open foliage roosts are rare. Here, we present three observations of non-albinistic hypopigmentation in two neotropical bat species. One extensively hypopigmented individual of

Anomalous coat colour in the fat dormouse (Glis glis): a review with new records

We reviewed the available records on aberrantly coloured fat dormice