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Aberrant colourations in wild snakes: case study in Neotropical taxa and a review of terminology

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Abstract

The criteria used by previous authors to define colour aberrancies of snakes, particularly albinism, are varied and terms have widely been used ambiguously. The aim of this work was to review genetically based aberrant colour morphs of wild Neotropical snakes and associated terminology. We compiled a total of 115 cases of conspicuous defective expressions of pigmentations in snakes, including melanin (black/brown colour), xanthins (yellow), and erythrins (red), which involved 47 species of Aniliidae, Boidae, Colubridae, Elapidae, Leptotyphlopidae, Typhlopidae, and Viperidae. Most of them were hypopigmented conditions, mainly amelanism, but also anerythrism, axanthism, hypomelanism, leucism, piebald-ism, and albinism (total absence of pigments). Hyperpigmented aberrancies were mostly melanism and xanthism, plus a few instances of erythrism. No associations with diurnality and fossorial behaviour were observed, neither for blanched nor hyperpigmented aberrancies. A discussion of the terms most commonly used for wild snakes is provided, with an account of cases of aberrant colourations in other South American reptiles. Finally, we propose a simple classification framework of wild snake colour aberrancies based on predominant dorsal colour and eye pigmentation for the adoption of a standardized terminology, which may be applicable to other squamates and chelonians. We advocate the use of a more accurate terminology in the scientific literature that would avoid the use of confusing terms like "partial albinism".

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... Such colour abnormalities are extremely rare in nature and deserve to be carefully described. Borteiro et al. (2021), which we follow here, define, and name the different colouration anomalies encountered in wild snakes. ...
... The rings that make up the triads on its body, easy to discern, are orange (not red as usual), very pale pink (instead of black) and pearly (instead of white). The specimen is completely devoid of black pigments (melanin) and its eyes are red ( Fig. 2), which is typical only of amelanistic and albino individuals, but not of leucistic ones, in agreement with the new definitions provided by Borteiro et al. (2021) that we share. ...
... The amelanistic specimen from French Guiana that we here describe presents very clear melanin hypopigmentation and red eyes, but the red pigments are always present in the triads, which is not the case in albino individuals who also present red eyes. Borteiro et al. (2021) report only seven cases of colour abnormalities in the genus Micrurus: in Micrurus corallinus (Merrem, 1820), two cases of amelanism in juveniles, one uncategorised case, one case of anerythrism in an adult and one case of erythrism in an adult, all observed in Brazil; two cases of amelanism similar to ours with red eyes in M. lemniscatus (see Paredero et al., 2017); and one case in M. pyrrhocryptus (Cope, 1862) ( Table 1). We here add another aberrant Texas Coralsnake, Micrurus tener (Baird & Girard, 1853), illustrated in Fenolio and Lamar (2021) and indicated as anerythristic but which clearly is an amelanistic snake with typical red eyes similar to our specimen of M. lemniscatus from Saül. ...
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Description of a second case of amelanism by Micrurus lemniscatus (Linnaeus, 1758) coralsnake from Saül, French Guiana. Micrurus tener, anerythrism. Texas, USA Micrurus corallinus, amelanism, São Paulo, Brazil. Santa Maria, Distrito Federal, Brazil. Micrurus pyrrhocryptus, Colonias Unidas, Chaco, Argentina, amelanistic. Albinos. Albinism. South America. Snakes. Reptiles.
... Aberrant colourations are uncommon in nature but have been reported for several species of fishes (Fontes et al., 2023), amphibians (Souza et al., 2021), reptiles (Borteiro et al., 2021), birds (Guay et al., 2012), and mammals (Ramos-Luna et al., 2022) worldwide. Colour variation in snakes has several functions, such as to provide warning signals, mimicry, camouflage, and aid in thermoregulation (Norris and Lowe, 1964). ...
... In the Neotropics, aberrant colourations in snakes have been documented across several families, including Colubridae, Boidae, Viperidae, Elapidae, Typhlopidae, Aniliidae, and Leptotyphlopidae (Borteiro et al., 2021). These instances of chromatic conspicuous anomalies correspond to unusual phenotypes, that were observed in some species of false coralsnakes of the genus Oxyrhopus, such as albinism (Amaral, 1927) and erythrism (Amaral, 1932) in Oxyrhopus guibei, melanism in Oxyrhopus occipitalis (Costa-Campos et al., 2015), and amelanism in Oxyrhopus petolarius petolarius (Esqueda et al., 2005;Borteiro et al., 2021). ...
... In the Neotropics, aberrant colourations in snakes have been documented across several families, including Colubridae, Boidae, Viperidae, Elapidae, Typhlopidae, Aniliidae, and Leptotyphlopidae (Borteiro et al., 2021). These instances of chromatic conspicuous anomalies correspond to unusual phenotypes, that were observed in some species of false coralsnakes of the genus Oxyrhopus, such as albinism (Amaral, 1927) and erythrism (Amaral, 1932) in Oxyrhopus guibei, melanism in Oxyrhopus occipitalis (Costa-Campos et al., 2015), and amelanism in Oxyrhopus petolarius petolarius (Esqueda et al., 2005;Borteiro et al., 2021). ...
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On 16 August 2005, an anomalous individual of Oxyrhopus guibei was discovered during fauna rescue operations at the Corumbá IV Hydroelectric Power Plant (-16.323099°S, -48.184586°W; datum SAD 69), Goiás, Brazil. The snake was photographed and released immediately outside of the area scheduled to be flooded by the hydroelectric plant. During approximately 15 months of fieldwork, 53 other specimens of O. guibei with normal colouration were observed. The aberrant specimen presented the normal pattern of the species but did not exhibit the usual noticeable red pigmentation expressed in body annuli and eyes. We classify this phenotype as a case of anerythrism according to Borteiro et al. (2021).
... R eptiles have diverse color patterns that serve ecological, behavioral, and physiological functions (e.g., camouflage, mimicry, thermoregulation, and warning) (Bechtel 1978;Allen et al. 2013). However, chromatic aberrations resulting in atypical coloration, which have been recorded in a number of species, can reduce survival and fitness (Krecsák 2008;Cyriac and Kodandaramajah 2019;Ascoli-Morrete et al. 2021;Borteiro et al. 2021;Rivas et al. 2022). The most common chromatic aberrations include albinism, in which affected individuals partially or totally lack melanin, resulting in pinkish-white skin and reddish pupils. ...
... Leucism is expressed when the affected individuals suffer a partial loss of all types of pigmentation, resulting in pale skin, often with white patches, but having dark eyes. Finally, xanthism and erythrism result in the affected individuals lacking dark pigments but expressing yellow or red pigments, respectively, resulting in largely yellowish or reddish skin (Bechtel 1978;Rivera et al. 2001;Travaglia 2006;Roncolatto et al. 2017;Andrade et al. 2020;Mendonça et al. 2020;Borteiro et al. 2021). ...
... Xanthism has been documented in several viperids, including Bothrops alternatus, B. jararacussu, B. jararaca, B. cotiara, and Crotalus durissus (Mendonça et al. 2020;Ruiz-Sueiro et al. 2010;Travaglia 2006), but in fewer colubroids (e.g., Dipsas sp.) and boids (e.g., Epicrates cenchria) (see Hoge and Belluomini 1957;Borteiro et al. 2021). ...
... R eptiles have diverse color patterns that serve ecological, behavioral, and physiological functions (e.g., camouflage, mimicry, thermoregulation, and warning) (Bechtel 1978;Allen et al. 2013). However, chromatic aberrations resulting in atypical coloration, which have been recorded in a number of species, can reduce survival and fitness (Krecsák 2008;Cyriac and Kodandaramajah 2019;Ascoli-Morrete et al. 2021;Borteiro et al. 2021;Rivas et al. 2022). The most common chromatic aberrations include albinism, in which affected individuals partially or totally lack melanin, resulting in pinkish-white skin and reddish pupils. ...
... Leucism is expressed when the affected individuals suffer a partial loss of all types of pigmentation, resulting in pale skin, often with white patches, but having dark eyes. Finally, xanthism and erythrism results in the affected individuals lacking dark pigments but expressing yellow or red pigments, respectively, resulting in largely yellowish or reddish skin (Bechtel 1978;Rivera et al. 2001;Travaglia 2006;Roncolatto et al. 2017;Andrade et al. 2020;Mendonça et al. 2020;Borteiro et al. 2021). ...
... Xanthism has been documented in several viperids, including Bothrops alternatus, B. jararacussu, B. jararaca, B. cotiara, and Crotalus durissus (Mendonça et al. 2020;Ruiz-Sueiro et al. 2010;Travaglia 2006), but in fewer colubroids (e.g., Dipsas sp.) and boids (e.g., Epicrates cenchria) (see Hoge and Belluomini 1957;Borteiro et al. 2021). ...
... Melaninausprägung aufgrund einer Verringerung der Melaninpigmente gekennzeichnet ist, was zu beigen, goldenen, gelblichen oder rötlichen Individuen mit unzureichend pigmentierter Haut führt und durch homozygot rezessive Allele verursacht wird (Borteiro et al. 2021;Bechtel 1995;Campell et al. 2010). Hypomelanismus wurde zuvor bei einem Exemplar von Bungarus caeruleus (Schneider, 1801) aus Maharashtra, Indien beobachtet (Borteiro et al. 2021 Individuen, die in der Natur zu geringeren Überlebensraten führen (Bechtel & Bechtel 1981;Bechtel 1995;Krecsák 2008 The process of pigmentation and its distribution by specialized skin cells called chromatophores (melanophores, and xanthophores including erythrophores) are responsible for various types of coloration exhibited by snakes which plays a significant role in concealment, mimicry, warning signals and thermoregulatory advantages at times (Norris & Lowe 1964;Bechtel 1978). ...
... Melaninausprägung aufgrund einer Verringerung der Melaninpigmente gekennzeichnet ist, was zu beigen, goldenen, gelblichen oder rötlichen Individuen mit unzureichend pigmentierter Haut führt und durch homozygot rezessive Allele verursacht wird (Borteiro et al. 2021;Bechtel 1995;Campell et al. 2010). Hypomelanismus wurde zuvor bei einem Exemplar von Bungarus caeruleus (Schneider, 1801) aus Maharashtra, Indien beobachtet (Borteiro et al. 2021 Individuen, die in der Natur zu geringeren Überlebensraten führen (Bechtel & Bechtel 1981;Bechtel 1995;Krecsák 2008 The process of pigmentation and its distribution by specialized skin cells called chromatophores (melanophores, and xanthophores including erythrophores) are responsible for various types of coloration exhibited by snakes which plays a significant role in concealment, mimicry, warning signals and thermoregulatory advantages at times (Norris & Lowe 1964;Bechtel 1978). The dormancy or the absence of one or more chromatophore types often leads to chromatic anomalies that are usually not uncommon in snakes (Prüst 1984;Bechtel 1991). ...
... The dormancy or the absence of one or more chromatophore types often leads to chromatic anomalies that are usually not uncommon in snakes (Prüst 1984;Bechtel 1991). The terminologies for such anomalies in animals needs to be specifically classified since the most frequently used easiest terms for describing such conditions include 'hypopigmentation' and 'partial albinism' (Prüst 1984;Bechtel 1991;Kornilios 2014 matic aberration characterized by diminished melanin expressions due to reduction of melanin pigments resulting in beige, golden, yellowish or reddish individuals with insufficiently pigmented skin and are caused by homozygous recessive alleles (Borteiro et al. 2021;Bechtel, 1995;Campbell et al. 2010). Hypomelanism has been previously reported in a specimen of Bungarus caeruleus from Maharashtra, India (Borteiro et al. 2021). ...
... Skin color arises due to the presence of pigments in chromatophores. In reptiles, a range of colors can be expressed by different kinds of chromatophores, such as melanophores, xanthophores, and erythrophores, each one bearing a set of pigments, and when the production of a pigment is excessive or reduced (sometimes absent), there is a color anomaly (Betchel, 1978;Borteiro et al., 2021). Among a series of possible deviations from the typical coloration pattern, hypopigmentation (amelanism, leucism, and albinism, sensu Borteiro et al., 2021) is characterized by the lack of melanin in different degrees, affecting part or the whole body (Burns et al., 2008). ...
... In reptiles, a range of colors can be expressed by different kinds of chromatophores, such as melanophores, xanthophores, and erythrophores, each one bearing a set of pigments, and when the production of a pigment is excessive or reduced (sometimes absent), there is a color anomaly (Betchel, 1978;Borteiro et al., 2021). Among a series of possible deviations from the typical coloration pattern, hypopigmentation (amelanism, leucism, and albinism, sensu Borteiro et al., 2021) is characterized by the lack of melanin in different degrees, affecting part or the whole body (Burns et al., 2008). Although hypopigmentation is a phenomenon probably occurring in all vertebrate species, a survey conducted a decade ago found that this anomaly had been recorded in only 620 wild species, primarily among birds (McCardle, 2012). ...
... Although hypopigmentation is a phenomenon probably occurring in all vertebrate species, a survey conducted a decade ago found that this anomaly had been recorded in only 620 wild species, primarily among birds (McCardle, 2012). In reptiles, hypopigmentation has been reported in lizards, snakes, turtles, and crocodilians (e.g., Rocha and Rebelo, 2010;Erickson and Kaefer, 2015;Grigg and Kirshner, 2015;Borteiro et al., 2021;Paiva et al., 2022), through mutations in different genes such as oca2, Mc1r, and TYR (Rosemblum et al., 2004;Borteiro et al., 2021). ...
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Hypopigmentation is characterized by the lack of melanin in part or the whole body. For nocturnal or fossorial reptiles, hypopigmentation may be less disadvantageous, as they are less exposed to visually oriented predators. But chromatic anomalies are challenging to observe in fossorial species, such as worm lizards (Amphisbaenia), because they are difficult to detect in the wild. We assessed information on hypopigmentation in the worm lizard genus Blanus based on two citizen science platforms and found the first record of piebaldism in B. aporus, new records of piebaldism in B. vandellii and B. strauchi, and the first record of amelanism in B. cinereus. This underscores the relevance of citizen science for obtaining new data on chromatic anomalies in fossorial animals. Hypopigmentation occurs more frequently in Blanus than previously known and most, if not all new records were observed in adults, supporting the hypothesis that this chromatic anomaly is less disadvantageous to fossorial reptiles.
... A wide variety of chromatic aberrations in Neotropical snakes have been documented e.g., anerythrism, erythrism, melanism, amelanism, hypomelanism, xanthism, axanthism, albinism, leucism, and piebaldism (Noronha et al., 2013;Travaglia-Cardoso et al., 2014;Abegg et al., 2015;Mira-Mendes et al., 2017;Ortiz et al., 2017;Paredero et al., 2017;Cruz-da-Silva et al., 2018;Lopes et al., 2019;Ascoli-Morrete et al., 2021;Borteiro et al., 2021;Urra et al., 2021;Fernandes et al., 2022). ...
... Hypomelanism is an inherited chromatic aberration characterised by diminished melanin expression with pigmented eyes (Borteiro et al., 2021). This condition has been reported in several species of South American snakes of the genus Dipsas, Drymarchon, Erythrolamprus and Philodryas in the family Colubridae, and Bothrops in the family Viperidae (Lema, 1960;Abegg et al., 2014;Vargas, 2015;Machín et al., 2018;Mendonça et al., 2020;Borteiro et al., 2021;Costa et al., 2021). ...
... Hypomelanism is an inherited chromatic aberration characterised by diminished melanin expression with pigmented eyes (Borteiro et al., 2021). This condition has been reported in several species of South American snakes of the genus Dipsas, Drymarchon, Erythrolamprus and Philodryas in the family Colubridae, and Bothrops in the family Viperidae (Lema, 1960;Abegg et al., 2014;Vargas, 2015;Machín et al., 2018;Mendonça et al., 2020;Borteiro et al., 2021;Costa et al., 2021). Wild hypomelanistic individuals face a suite of ecological challenges, including increased damage from solar radiation (Brenner and Hearing, 2007), difficulty in avoiding predators (Childs, 1953), and visual impairment (Balkema and Dräger, 1991). ...
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We describe an individual of Anilius scytale (Aniliidae) from the bolivian Amazon, presenting hypomelanism, the first record of this kind of chromatic aberration in this species.
... Chromatic aberrancies are common in animals (Witkop, 1975), and atypical colourations are widespread in neotropical snakes (Abegg et al., 2014;Ortiz et al., 2017;Borteiro et al., 2021). Since the skin colour of snakes plays an important role in concealment, mimicry, warning signals, and thermoregulation (Norris and Lowe, 1964;Bechtel, 1995), chromatic aberrancies are presumed to compromise their protection, health and survivorship, increasing the probability of detection by predators and diminishing the protection against solar radiation (Bechtel and Bechtel, 1981;Krecsák, 2008). ...
... Following the criteria proposed by Borteiro et al. (2021), we classify this specimen of L. muta as presenting the 'amelanistic' condition. Amelanism is caused by a genetic disorder in the genes responsible for the intensity of pigmentation in the skin, hair, and eyes (Walter, 2018). ...
... Amelanism is caused by a genetic disorder in the genes responsible for the intensity of pigmentation in the skin, hair, and eyes (Walter, 2018). Therefore, the release of pigment by melanocytes is compromised, resulting in the inability to produce melanin, the pigment responsible for black and brown colouration (Borteiro et al., 2021). Typically, individuals with this condition have red eyes and white or pink skin (Borteiro et al., 2021). ...
... camouflage, warning, thermoregulation, mimicry) (Bechtel 1978;Cooper and Greenberg 1992;Allen et al. 2013). Chromatic aberrancies have been reported in numerous snake species, including many neotropical taxa (Bechtel 1978;Dyrkacz 1981;Krecsák 2008;Borteiro et al. 2021). Chromatic aberrancies or atypical coloration has been argued to reduced fitness and survival in snakes (Krecsák 2008;Cyriac and Kodandaramaiah 2019). ...
... Common aberrant color patterns of hyperpigmentation and/or hypopigmentation in snake species include albinism, characterized by total (red eyes and completely pigmentless body) to partial absence of pigmentation; leucism, defined by normally pigmented eyes and partially or totally pigmentless body; xanthism and erythrism characterized by the overabundance of yellow or red pigment, respectively; and melanism, an overexpression of the black pigment melanin (Harris 1970;Bechtel 1978Bechtel , 1995Dyrkacz 1981). Due to ambiguity in the literature, Borteiro et al. (2021) recently redefined and clarified the criteria and terminology used to describe aberrant color patterns in wild snakes. ...
... Henderson (1997Henderson ( , 2002 examined more than 600 specimens from throughout the species' range, including over 170 specimens from mainland South America; less than 5.9% were flecked or patternless yellow individuals, none of them from Bolivia. Henderson (1997) and Duarte et al. (2015) made important contributions via their detailed analyses of morphotypes and color patterns of C. hortulana, we argue that the light-colored, designless Morphotype 6 of Duarte et al. (2015), as well as the yellow, flecked Character State 6 and yellow, patternless Character State 7 of Henderson (1997) all meet the criteria of xanthism (i.e., overexpression of yellow pigmentation associated with the lack of red, brown, or black pigmentation) (Harris 1970;Bechtel 1978Bechtel , 1995Dyrkacz 1981;Borteiro et al. 2021). ...
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Snakes display a wide range of skin colors and patterns, acting in ecological, behavioral, and physiological roles. Xanthism has been reported in numerous snake species, including many neotropical taxa. Corallus hortulana is a polychromatic species widely distributed throughout South America. Yellow, patternless individuals, while rare, have been recognized as within the species’ polychromatic range. We report the first yellow, patternless specimens of Corallus hortulana collected in Bolivia and discuss whether these individuals fit the criteria of xanthism. KEYWORDS: snakes; polychromatism; chromatic aberrancies; Amazon
... Conspicuous chromatic anomalies occur due to pigmentation production disturbances causing aberrant coloration of the skin (Rook et al., 1998). Such anomalies are not common in wild squamates, but have been frequently reported for snakes, especially cases of hypopigmentation (Borteiro et al., 2021). Traditionally, hypopigmentation anomalies were classified as albinism, leucism, and piebaldism. ...
... On the other hand, in leucism and piebaldism, which are also known as 'partial albinism' , the eyes are pigmented, but there is an almost complete absence of pigmentation in skin (leucism) or there is a pattern of unpigmented patches along the body (piebaldism) (Prüst, 1984;Bechtel, 1991;Lamoreux et al., 2010;Abreu et al., 2013). Recently, Borteiro et al. (2021) reviewed color anomalies in Neotropical snakes and proposed a standardized terminology to be used in reptiles, particularly in cases of hypopigmentation: amelanism, albinism, hypomelanism, leucism, and piebaldism. ...
... The photographed specimen reported here clearly lacks normal pigmentation, except for some pale-yellow segments on the posteriormost portion of the body, including the tail (Fig. 1C). Based on the terminology proposed by Borteiro et al. (2021), the present case cannot be considered albinism, as there is not a 'total absence of pigments' , evidenced by the presence of yellowish stains on the body. The absence of melanin rules out that it may be a case of hypomelanism, leucism or piebaldism (Borteiro et al., 2021). ...
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Color anomalies are rarely reported in Amphisbaenia. We present the first record of amelanism in this group based on a specimen of Amphisbaena darwinii from Argentina. The photos were uploaded to a citizen science platform, reinforcing the positive impact of citizen science to filling gaps in our knowledge about biodiversity.
... Based on these aspects, we decided the condition of this individual is albinism. However, amelanism may result in a pink coloration in normally dark species (Borteiro et al. 2021), as could be the case in Geophis hoffmanni. As a result, this putative albinism should be studied carefully (Borteiro et al. 2021). ...
... However, amelanism may result in a pink coloration in normally dark species (Borteiro et al. 2021), as could be the case in Geophis hoffmanni. As a result, this putative albinism should be studied carefully (Borteiro et al. 2021). Nevertheless, based on the very uniform pinkish coloration of our individual (Fig. 2), and its pink eyes (although amelanistic individuals also have pink eyes), and not having more evidence of the causes of the anomaly, we determined it as albinism. ...
... Although several cases reported in the literature as albinism in snakes are really amelanism (Borteiro et al. 2021), this condition is not unknown, although rare, in nature, especially among adult snakes (Krecsák 2008). It has been postulated that success of albino snakes in nature is higher in cryptic or nocturnal species, or in species that have effective defense mechanisms (Sazima and Di-Bernardo 1991). ...
... Genetic mutations can lead to the emergence of aberrant or anomalous color patterns that can directly interfere with the fitness of individuals, as these anomalies often tend to reduce their chances of survival (Cyriac and Kodandaramaiah 2019). Albinism and melanism are the most common chromatic anomalies recorded in snakes (Prust 1984, Borteiro et al. 2021. Recently, a new classification for chromatic anomalies found in snakes was proposed, to correcting some cases of individuals that had been classified as albinos but were actually of leucism (Borteiro et al. 2021). ...
... Albinism and melanism are the most common chromatic anomalies recorded in snakes (Prust 1984, Borteiro et al. 2021. Recently, a new classification for chromatic anomalies found in snakes was proposed, to correcting some cases of individuals that had been classified as albinos but were actually of leucism (Borteiro et al. 2021). Leucism is an anomalous color pattern caused by the almost total absence of epidermal and dermal chromatophores, which may present some remnants of dispersed iridophores (Bechtel andBechtel 1985, Borteiro et al. 2021). ...
... The tongue and internal part of the nasal orifices were dark purple color, with to pink labial pits (Figure 1). This coloration characterizes frame the individual as leucistic according to the classification of Borteiro et al. (2021), this being the first record in the wild of this chromatic anomaly for C. hortulana. ...
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Snakes have a wide variety of color patterns that can be related to specific ecological and physiological functions. However, genetic mutations can lead to the appearance of anomalous color patterns, which can directly interfere with the fitness of individuals. Leucism is a chromatic anomaly characterized by the almost total absence of epidermal and dermal chromatophores that produce the color. Corallus hortulana is an arboreal snake with nocturnal habits, widely distributed throughout South America, with a wide range of color patterns, known as polychromatism. Here we report the first case of leucism in Corallus hortulana and discuss the potential ecological implications of this anomaly in this species. KEYWORDS: Amazonia; Squamata; coloration; color pattern; snakes; French Guiana
... Abnormal white vertebrates are a result of chromatic anomalies such as leucism, amelanism, or albinism (Borteiro et al. 2021;van Grow 2021). Leucistic animals are characterized by partial or total absence of pigmentation, such that the body appears with anomalous white coloration, but they still possess normally colored eyes (Lodi and Borobia 2013;van Grouw 2021). ...
... Leucistic animals are characterized by partial or total absence of pigmentation, such that the body appears with anomalous white coloration, but they still possess normally colored eyes (Lodi and Borobia 2013;van Grouw 2021). Amelanistic animals have white bodies and red eyes due to the absence of melanin, but have produced other pigments so that other colors may be present (Borteiro et al. 2021). Albinism encloses a group of genetically determined disorders of the melanin pigmentary system (Cremer et al. 2014). ...
... In many cases this is a result of albinism, a condition characterised by lack of retinal and integumentary pigmentation that results in white or pinkish skin and red eyes (Lamoreux et al., 2010). However, some animals are white due to amelanism; they also have red eyes due to the absence of melanin but have produced other pigments so that other colours may be present (Borteiro et al., 2021). In the literature, there are clear cases of confusion between these two anomalies (Borteiro et al., 2021). ...
... However, some animals are white due to amelanism; they also have red eyes due to the absence of melanin but have produced other pigments so that other colours may be present (Borteiro et al., 2021). In the literature, there are clear cases of confusion between these two anomalies (Borteiro et al., 2021). Here we present a case of amelanism in the Nicaraguan slider turtle at the Caño Negro wetlands in the northern plains of Costa Rica. ...
... In wild populations of other species like some snakes and mammals, cases of anomalous coloration are rare for several reasons which include potential increase of predation, reduction in prey capture success, and disruption of mate attraction (Sazima & Di-Bernardo 1991, Sobroza et al. 2016, Borteiro et al. 2021). Furthermore, individuals with different color abnormalities have been recorded to have altered immunological pathologies, such as sensory or nerve defects, anemia, reduced fertility, higher susceptibility to disease, and poor vision (Acevedo & Aguayo 2008, Summers 2009). ...
... Whole-body colour polymorphisms are well known in many snake species bred for the pet trade, especially in ball pythons (Python regius; Dao et al., 2023;Garcia-Elfring et al., 2023), and more and more reports of colour aberrations in snakes encountered in the wild are being published (e.g., Deshmuk et al., 2020;Devkota et al., 2020Devkota et al., , 2021Borteiro et al., 2021;Mukherjee and Mohan, 2021). It has now also been firmly established that certain genes responsible for the development and layering of chromatophores produce these colour patterns, and that it is not merely a simple matter of dominant or recessive conditions that follow Mendelian principles but a complex interplay of chromatophore gene suites, each with multiple alleles (e.g., Cox et al., 2013;Kuriyama et al., 2020;Curlis et al., 2021;Dao et al., 2023;Garcia-Elfring et al., 2023). ...
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Along with the well-documented color polymorphisms of various snakes bred in the pet trade, more and more reports of color aberrations in snakes encountered in the wild are being published. This is likely a consequence of the increased activities of snake rescue teams around the globe and the resultant higher level of snake awareness among local human populations. We found unusual color morphs in two vipers, Daboia russelii, and a wolfsnake, Lycodon aulicus, in India. These snakes display a strongly abnormal coloration, with near-leucistic and unpatterned vipers and a nearly unpatterned wolfsnake. Yet each of these snakes possesses striking vertebral lines. The uniformly brown L. aulicus has a normal neck band but the expected transverse banding pattern is missing. The coloration of the vertebral scale row and its two adjacent scales creates a longitudinal pattern of a dark brown vertebral line framed in a cream color, beginning 11 scales beyond the parietals and extending two thirds the body length. In contrast, the line pattern in the vipers begins at the neck and consists of three un- or lightly pigmented scales along the vertebral line, framed by a single row of dark scales on either side and extending more faintly onto the posterior part of the body. While the primarily white viper from Gujarat retains the dark lateral rings that typically offset different shades of brown in normal phenotypes, the body of the subadult from Goa is a patternless light brown. The patterning is strongly reminiscent of a genetic modification in the pathway controlling chromatophore development that has been called spark/spark in ball pythons (Python regius). Detailed genetic studies of this phenomenon would be ideal, but the uniqueness of these color aberrations in these two species makes such work impractical – but it reveals nature as a sometimes-eccentric painter of lines.
... To date, our records are the first described cases of piebaldism in caecilians. Borteiro et al. (2021) reviewed cases of chromatic anomalies in snakes and pointed out that, due to the lack of standardization, different anomalies are recognized under the same terminology. These authors established criteria to report on chromatic anomalies in snakes, but this standardization does not exist for amphibians. ...
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This study explores anomalous color patterns in caecilians, specifically Siphonops annulatus and Siphonops paulensis, documenting the first cases of piebaldism in Gymnophiona. The research delves into the diverse functions of color patterns. Although uncommon in nature, anomalous color patterns provide intriguing insights into genetic mechanisms and ecological adaptations. We present two adult caecilians exhibiting piebaldism—one from Yasuní National Park, Ecuador, and another from Guaramiranga, Brazil. The specimens exhibit irregular dark spots on a whitish background. This study describes their colour pattern and summarizes anomalous colourations in caecilians.
... Sin embargo, existen casos de coloraciones raras o anormales debido a una pigmentación excesiva o reducida (Kolenda et al., 2017;Allain et al., 2023). El eritrismo, coloración anormal en donde se presentan principalmente coloraciones rojizas y naranjas en diferentes tonalidades, es de las menos frecuentes entre los reptiles, y ha sido principalmente registrada en serpientes (Gilhen, 2010;Borteiro et al., 2021;Jablonski et al., 2022). ...
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The first documented record of abnormal coloration (erythrism) in the long-tailed snake (Thamnophis scalaris) is reported in San Cayetano Morelos, Toluca, State of Mexico in a disturbed habitat.
... H ypopigmentary anomalies (HAs) are chromatic disorders of various etiologies that result in lighter colourations due to a decrease or lack of pigments. A standardised terminology for chromatic anomalies in reptiles has recently been proposed by Borteiro and colleagues, including definitions for the main HAs such as amelanism, albinism, hypomelanism, leucism, and piebaldism (Borteiro et al., 2021). Among wild reptiles, HAs are mostly known in snakes while they are rarer in other squamates, including geckos. ...
... Melanism is a chromatic anomaly resulting from the excessive production of pigments in melanophores related to dark colours (melanin, phaeomelanin or eumelanin) in the dermis and epidermis (Chavin, 1969;Borteiro et al., 2021). The structural organisation of chromatic cells in the dermis normally presents melanophores in deeper layers with the other chromatophores just above composing the colour pattern, which jointly create the colouration pattern (Goda and Kurivama, 2021). ...
... The Barred Wolf snake is a non-venomous colubrid that ranges throughout much of peninsular India. The body is dark brown or black above, with white transverse spots or cross bands, which are widely separated anteriorly; the sides are lineolate with white and a black spot corresponding to each white cross band; upper lip and venter are uniformly white; the head is only slightly distinct from the neck; the snout is flattened; 8 upper labials, the first and second in contact with the nasal [6][7][8][9][10][11][12][13][14]. ...
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Body patterns in snakes vary as per the species, geographical location, and adaptive requirements of species and it is created by the presence of different pigments in the skin. The patterns tend to provide various functions from basic to more specific ones. The barred wolf snake is one of the snakes showing morphological color patterns and is often used for its identification purpose. Color aberration in snake is observed as common-phenomena. Here in, we have documented a unique aberration in the barred wolf snake.
... Yet, it remains, that we can only speculate about the biological significance that is behind such reddish phenotypes and their rare manifestations in wild snake popula- tions (cf. Mačát et al. 2016;Zúñiga-Baos 2020;Borteiro et al. 2021). Thus, due to the rarity of this colour morph in Grass Snakes, we would like to encourage more field herpetologists and naturalists to present their unusual observations of Grass Snakes with reddish colouration. ...
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We describe the unusual case of erythrism in the Eastern Grass Snake, Natrix natrix. This colour morph is very rare and has not been reported in the literature before. Despite having observed thousands of N. natrix in the field, we personally detected this morph in only three individuals originating from Slovakia, Romania, and mainland Greece, while photos of a fourth individual from a Greek island were provided to us. In addition, a recent study with a large data set from citizen scientists was unable to produce a single reddish Eastern Grass Snake. Such colouration is likewise uncommon in the western members of Grass Snakes (N. helvetica, N. astreptophora), with two examples provided herein. Because the potential biological importance of erythristic colouration is unclear, we encourage other field herpetologists and naturalists to publish their observations of reddish Grass Snakes in the printed literature.
... In wild populations of other species like some snakes and mammals, cases of anomalous coloration are rare for several reasons which include potential increase of predation, reduction in prey capture success, and disruption of mate attraction (Sazima & Di-Bernardo 1991, Sobroza et al. 2016, Borteiro et al. 2021). Furthermore, individuals with different color abnormalities have been recorded to have altered immunological pathologies, such as sensory or nerve defects, anemia, reduced fertility, higher susceptibility to disease, and poor vision (Acevedo & Aguayo 2008, Summers 2009). ...
Article
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Piebaldism, leucism or albinism are different types of pigmentation anomalies related to the excess or deficit of pigmentation in some regions or in the whole body of an animal. It is extremely rare in peccaries and has never been reported for Tayassu, a genus endemic to Neotropical region. Tayassu pecari, known as white-lipped peccaries (WLP's), have behaviors and ecology well documented in literature, but there is no published scientific information about pigmentation anomalies. Here, we report the first records of anomalous individuals (leucism and piebaldism) for WLP's in locations of Central Brazil. During fieldwork for mammal survey (2010-2020) search for individuals with pigmentation anomalies were carried out in ten sites spread across four Brazilian biomes: Atlantic Forest, Cerrado, Amazon Forest, and Pantanal. Thirteen individuals were registered throughout eight locations in the last three biomes. All these individuals were part of a herd in which most individuals occurred with normal pigmentation. The Cerrado was the most representative biome in which individuals with abnormal pigmentation were recorded (46.2%) followed by the Amazon (30.8 %) and the Pantanal (23.0%). Despite the long-term survey by camera traps (70,000 nights of camera traps), only 0.1% of the records were of WLP with anomalous coloration. Our work presents, for the first time, WLP with leucism and piebaldism, and a range of chromatic variations. It was not possible to determine how leucism affects the health and survival of the individuals that have it, therefore, our work encourages future field studies that can monitor the behavior and fitness of those individuals for extended periods.
... We also did not focus on gathering photos that could be identified only to the genus or higher taxonomic level, photos of snakes in captivity (including captive-bred color morphs), or photos of captive-bred or naturally-occurring hybrids (LeClere et al., 2012;Mebert, 2008). Aberrant coloration and patterning occurs at low frequencies in wild snakes (Borteiro et al., 2021), and individual, regional, ontogenetic, and coloration and patterning are common (Bechtel, 1978;Farooq and Uetz, 2020), so continuing to collect photos even of common species has value. 4. Peer-reviewed literature. ...
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The secretive behavior and life history of snakes makes studying their biology, distribution, and the epidemiology of venomous snakebite challenging. One of the most useful, most versatile, and easiest to collect types of biological data are photographs, particularly those that are connected with geographic location and date-time metadata. Photos verify occurrence records, provide data on phenotypes and ecology, and are often used to illustrate new species descriptions, field guides and identification keys, as well as in training humans and computer vision algorithms to identify snakes. We scoured eleven online and two offline sources of snake photos in an attempt to collect as many photos of as many snake species as possible, and attempt to explain some of the inter-species variation in photograph quantity among global regions and taxonomic groups, and with regard to medical importance, human population density, and range size. We collected a total of 725,565 photos—between 1 and 48,696 photos of 3098 of the world's 3879 snake species (79.9%), leaving 781 “most wanted” species with no photos (20.1% of all currently-described species as of the December 2020 release of The Reptile Database). We provide a list of most wanted species sortable by family, continent, authority, and medical importance, and encourage snake photographers worldwide to submit photos and associated metadata, particularly of “missing” species, to the most permanent and useful online archives: The Reptile Database, iNaturalist, and HerpMapper.
Article
Reptiles display great diversity in color and pattern, yet much of what we know about vertebrate coloration comes from classic model species such as the mouse and zebrafish.1,2,3,4 Captive-bred ball pythons (Python regius) exhibit a remarkable degree of color and pattern variation. Despite the wide range of Mendelian color phenotypes available in the pet trade, ball pythons remain an overlooked species in pigmentation research. Here, we investigate the genetic basis of the recessive piebald phenotype, a pattern defect characterized by patches of unpigmented skin (leucoderma). We performed whole-genome sequencing and used a case-control approach to discover a nonsense mutation in the gene encoding the transcription factor tfec, implicating this gene in the leucodermic patches in ball pythons. We functionally validated tfec in a lizard model (Anolis sagrei) using the gene editing CRISPR/Cas9 system and TEM imaging of skin. Our findings show that reading frame mutations in tfec affect coloration and lead to a loss of iridophores in Anolis, indicating that tfec is required for chromatophore development. This study highlights the value of captive-bred ball pythons as a model species for accelerating discoveries on the genetic basis of vertebrate coloration.
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We describe a distinctive new subspecies of sea snake from the occasionally anoxic inner-basin waters of Golfo Dulce, Costa Rica, based on combined data garnered between 2010 and 2017 for 154 specimens, 123 free-ranging and 31 museum-held. The yellow sea snake, Hydrophis platurus xanthos Bessesen & Galbreath, subsp. n., is diagnosed by a notably smaller body size and nearly uniform yellow coloration, which contrasts with the black and yellow striae and tail spots or bands typical of the species. Within the modest geographic range (circa 320 km²), nearly all specimens possess both diagnostic character states. Bathymetrics appear to restrict genetic flow between this allopatric population and conspecifics in the broader Eastern Pacific. In perspicuous contrast to typical H. platurus, H. p. xanthos shows no association with drift lines, and feeds at night in turbulent waters, assuming a sinusoidal ambush posture never previously reported for the species. This evolutionarily significant unit (ESU) warrants taxonomic recognition and active protection.
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Xenodon merremi is a polychromatic species distributed in South America. Among its wide range of color patterns, the most common pattern resembles a pitviper of the genus Bothrops. In this work is recorded the different patterns found in Paraguayan populations of X. merremi. Four patterns can be observed: marked pattern, slightly marked pattern, smooth, and banded pattern. The marked pattern is the most common pattern (mimetic with pitvipers), and all juveniles bear this coloration. Only adults show variation in their coloration.
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I n earlier times, when little or nothing was known about plumage pigmentation and mutations, aberrantly coloured wild birds were often regarded as new species or sub-species and several were formally named. Perhaps the oldest example of a colour aberration named as a distinct species is the 'Mountain Partridge' Perdix montana (Brisson, 1760). In Brisson's time this 'species' was known only from the mountains of the French region of Lorraine, which resulted in it being named P. montana ('of the mountains'). However, it was subsequently revealed to be simply a melanistic form of the Grey Partridge P. perdix. Sabine's Snipe Scolopax sabinii (Vigors, 1825) is another example – this dark-coloured snipe is actually a melanistic form of the Common Snipe Gallinago gallinago. Aberrant plumage colour is not uncommon in birds. Indeed, in some species it is sufficiently common that the aberrant forms represent a fairly large proportion of the whole population and are thus considered to be a colour morph within the species. In such cases the term 'polymorphism' is often used instead of aberration. Melanism is the most common polymorphism represented in birds (Mundy 2006). Pomarine Stercorarius pomarinus and Arctic Skuas S. parasiticus are examples of species in which a dark (melanistic) morph is a standard colour feature. Genetic studies of domesticated animals, in particular mice and chickens, furnished us with a greater knowledge of pigmentation and mutations. At an early stage, it became obvious that different mammal species had a similar series of heritable coat-colour variants. Similar mutations were soon allocated the same name in all species. The similarity was based on the relevant gene action on the pigmentation process and not necessarily on the appearance of the final coat colour, as this can differ among species. Despite the comparable nature of the pigmentation process in birds and mammals, establishing some uniformity in the nomenclature of genes (loci) between mammals and birds has so far been neglected. Consequently, the naming of colour aberrations still causes problems in the ornithological world. A variety of names are still used seemingly randomly to identify the mutations. Most commonly misapplied is the name 'albino' or 'partial albino' (Rollin 1964; Buckley 1982, 1987; van Grouw 2006, 2010). The term 'albino' is widely used for all sorts of different colour aberrations, but in only a tiny proportion of cases is it used correctly. Albinism is actually far less common than was previously
Article
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The records of albino, partial albino, and leucistic individuals among four species of European Viperinae (Vipera ammodytes, Vipera aspis, Vipera seoanei, and Vipera berus) were summarized based on literature records, mu-seum material, reports of field herpetologists and herpetoculturists, and a short description of all reported speci-mens was made. For the first three species only scattered observations have been made (1, 1, and 6 reports), whereas at Vipera berus these defects proved to be more widespread (16 reports), and present an occurrence pat-tern shift to the Nordic countries. Different hypotheses are postulated on the offset geographic distribution pat-tern of albinism and leucism at this species, taking into account the differences in predation pressure and popula-tion densities between populations in Southern and Northern Europe. The possible negative effect of the color defects on the fitness and survival of the specimens carrying them is debated.
Article
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Models of snakes varying in color pattern have been used to test hypotheses about predation and mimicry. In the present study, clay models of the common garter snake were used to test for a dif-ference in attack frequency between adult and juvenile striped and melanistic garter snakes; such difference may indicate a difference in cryptic coloration between the two morphs. The research was performed on the shores of Sandusky Bay and Lake Erie, where polymorphic garter snake populations contain both striped and melanistic garter snakes. There was no difference in attack frequency between the two morphs; however, juvenile snake models were attacked more frequently than adult ones. The study suggests that melanism may not confer a strong disadvantage with respect to visually-oriented predators.
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Within populations, the stochastic effect of genetic drift and deterministic effect of natural selection are potentially weakened or altered by gene flow among populations. The influence of gene flow on Lake Erie populations of the common garter snake has been of particular interest because of a discontinuous colour pattern polymorphism (striped vs. melanistic) that is a target of natural selection. We reassessed the relative contributions of gene flow and genetic drift using genetic data and population size estimates. We compared all combinations of two marker systems and two analytical approaches to the estimation of gene flow rates: allozymes (data previously published), microsatellite DNA (new data), the island model (FST-based approach), and a coalescence-based approach. For the coalescence approach, mutation rates and sampling effects were also investigated. While the two markers produced similar results, gene flow based on FST was considerably higher (Nm > 4) than that from the coalescence-based method (Nm < 1). Estimates of gene flow are likely to be inflated by lack of migration-drift equilibrium and changing population size. Potentially low rates of gene flow (Nm < 1), small population size at some sites, and positive correlations of number of microsatellite DNA alleles and island size and between M, mean ratio of number of alleles to range in allele size, and island size suggest that in addition to selection, random genetic drift may influence colour pattern frequencies. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 79, 389–399.
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This paper presents the results of light and electron microscopy done on iridophores in the dorsal skin of the lizard Anolis carolinensis. New fine-structural details are revealed, and their importance is discussed. Of some interest is the complex of filaments between crystalline sheets in the cell. It is proposed that this complex is involved in the arrangement of crystals into crystalline sheets, and that the crystal arrangement and spacing are critical for the production of the cells' blue-green color. Tyndall scattering and thin-film interference are discussed as possible explanations for iridophore color production in relation to the fine-structural data obtained.
Article
The following snakes were located and acquired: two albino black rat snakes; one xanthic black rat snake, one hypopigmented black rat snake with phenotype not previously described; one leucistic Texas rat snake, one F 1 wild-type black rat snake heterozygous for albinism, and one male and two female F 1 wild-type Texas rat snakes heterozygous for albinism. Between 1975 and 1983 these snakes were subjected to various breeding combinations to determine their genetics. The results of 29 matings are summarized. All of the aberrant phenotypes were found to be autosomal recessive mutations. Allelic and nonallelic forms of albinism were found to exist in the black rat snake. The xanthic form of hypopigmentation was found to be tyrosinase—positive partial albinism. Leucism in the Texas rat snake appears to be associated with bilateral exophthalmos in some instances. The previously undescribed black rat snake phenotype was designated “brindle” because of its appearance. It appears to be a genetically determined alteration in the quantity or quality of pigment, or both, and it does not undergo ontogenetic loss of pattern. It is not a form of tyrosinase-positive albinism analogous to the xanthic phenotype.
Article
A review of reported instances of aberrant colors and patterns in the Indian herpetofauna is presented. A total of 70 instances from Indian States in last more than 120 years have been compiled and analyzed based on published literature and photographs uploaded on web-sites.
Article
The corn snake, Elaphe guttata guttata , is a colorful nonvenomous serpent of the eastern United States. Two color mutations are known to occur albinism and aner ythrism. Captive breeding has demonstrated that both mutations are autosomal recessive. Snakes homozygous for albinism have no black pigment; those homozygous for anerythrism have no red pigment. Even with hereditary absence of either color, both phenotypes exhibit marked individual color variation. Further captive propagation has demonstrated that each mutation is inherited independently, and snakes homozygous for both mutations, even though lacking both black and red, retain a distinct pattern and display individual color differences. Both mutations have been reported in widely separated portions of the range. Nonallellc forms of albinism are known in other snakes but have not been reported in corn snakes. Based on our evidence, nonallelic forms of anerythrism evidently exist in this species.
Article
The colors of living amphibians and reptiles have been studied, using a General Electric recording reflectance spectrophotometer. The animals were brought to activity temperature levels and the appropriate surface pressed over the reflectance port of the machine while a color record was taken. Background samples from the localities at which the animals were taken were also recorded. Reptiles and amphibians living on backgrounds of relatively uniform color tend to match that background through superposition with considerable fidelity. The animal's color curve is superimposed over that of the background. Ventral color in most forms tested was lighter than the dorsal surfaces of the same animal. It was darker only in some forest-dwelling salamanders and in desert lava-dwelling species. The difference results primarily from the highly reflective ventral surfaces of these forms. The ventral surfaces of white-bellied amphibia show clear oxyhaemoglobin absorption peaks, as do the dorsal surfaces of some amphibia. These effects are entirely absent in curves recorded from reptiles. It is concluded that the degree of background color-matching is related to: (a) the degree of color uniformity of the animal's background, (b) the degree of exposure of the color-matched species to predator, (c) the illumination level prevalent in the habitat, (d) the size range of the color-matched species, (e) the ecological restriction of the species, (f) the qualities of the visual apparatus of predators upon the species, and (g) the adaptive compromise struck by the species. The size of a color-matched animal, or the size of the part of its body that is normally exposed, is related to the point at which such color-matching breaks down. This point of just noticeable difference between animal and background is also determined by the wave-length discrimination curves of the predators, the closeness of the match involved, the uniformity of the background color and its texture, and the presence of absence of concealing patterns. Background color-matching varies greatly in its degree of perfection. This variation is the result of adaptive compromise and balance between this adaptive characteristic and many others that in one way or another affect its complete expression.
Article
The distribution and variation of the Carolina pigmy rattlesnake, Sistrurus m. miliarius, in North Carolina are described. Two color populations are recognized: an erythristic population inhabiting the northeastern periphery of the range, and a grayish population occurring in the southern portion of the state. The erythristic form is not afforded taxonomic status because of its limited range combined with an extensive area of intergradation.
Article
Four albino black rat snakes, Elaphe obsoleta obsoleta, one tan or xanthic in color and the other three completely amelanistic, were subjected to various breeding combinations to determine their genetic relationships. They were found to represent three distinct forms of albinism. Skin biopsies from the three forms were subjected to the dopa reaction, and biopsies from two of the forms were examined by frozen section. The two amelanistic forms were found to be non-allelic and to have biochemically different types of albinism, one tyrosinase-positive and the other tyrosinase-negative. The hypomelanistic or xanthic albino form was found to be tyrosinase-positive, allelic with the amelanistic tyrosinase-positive form, differing quantitatively in the biochemical defect in melanogenesis.
Article
Colors and patterns of snakes are reviewed and discussed from several viewpoints: function of color as distinguished from function of pattern; chromatogenesis, normal and abnormal; genetic control over chromatogenesis; normal variation in color and pattern; and abnormal variations in color and pattern.
Article
Examen de la couleur verte des Bothrops en realisant des coupes des ecailles dorsales chez un specimen adulte B. rowleyi afin de pouvoir les observer en microscopie optique, et d'obtenir une base pour la description et la comparaison
Article
The results of 11 captive matings among nine female and six male descendents of six wild-caught female common garter snakes from polymorphic populations near Lake Erie confirm that melanism is inherited as a simple Mendelian trait and is recessive to a striped pattern. The make-up of litters born to 71 wild-caught females from five sites corroborate this result: striped females never produced all melanistic litters and the frequency of entirely striped, mixed, and entirely melanistic litters conforms to expectations based on estimated allele frequencies. Possible explanations for a previously reported nou-Mendelian inheritance of melanism include the occurrence of a somatic mutation or bias in sperm production and fertilization ability.
Article
Ten phenotypic forms of oculocutaneous albinism (OCA) and four forms of ocular albinism (OA) have been identified in man. All have optic neuronal decussation defects at the optic chiasm. Thus any proposed animal model for these disorders must share optic neuronal decussation defects in addition to hypopigmentation. Three, tyrosinase-negative (ty-neg), yellow mutant (ym), and platinum (pt), OCA appear to be allelic in humans. Two, ty-neg and pt, OCA appear to be analogous to c-locus mutants c/c and cp/cp in mice, but no homologue is known in mice for ym OCA. Tyrosinase-positive (ty-pos) OCA, which is nonallelic with ty-neg OCA, shares many morphological and biochemical features with pink-eyed mice. Chediak-Higashi syndrome (CHS) and Hermansky-Pudlak syndrome (HPS) appear to be due to genes acting extrinsic to the melanin pathway. CHS is homologous with beige in mice. HPS was investigated in northwestern Puerto Rico, where it affects approximately 1 in 2,000 persons. Approximately 68% of 37 deceased HPS patients died from sequelae of ceroid storage disease, restrictive lung disease between ages 35 and 46 years (43%), and granulomatous colitis (8%) or hemorrhage (16%). The most accurate and consistent diagnostic feature of HPS is lack of platelet dense bodies. HPS patients with ceroid storage disease had high urinary levels of long-chain isoprenoid alcohols, dolichols, similar to that seen in the neuronal-ceroid lipofuscinoses (Batten disease). Dolichols are constituents of lysosomes, and their elevation in HPS suggests that this syndrome carries a lysosomal defect. There is no degradative pathway for ceroid and dolichols, which are eliminated by exocytosis. The exocytic process is thought to involve a thioendoproteinase. Pale-ear mice have been proposed as a model for HPS; their platelets lack dense bodies, and they are depigmented. Leupeptin, a thioendoproteinase inhibitor, administered to 100-day-old pale-eared and black wild-type C57 mice for 10 days resulted in the accumulation of ceroid in tissues in the same pattern as that in HPS, but granulomas of gut or fibrosis of lungs were not seen. Determinations of homology between mice and men at the molecular level is now possible with the isolation of mouse tyrosinase by Yamamoto et al. and isolation by Kwon et al. of human tyrosinase mapping at the c-locus in mice.
Article
Publisher Summary In addition to the presentation of positive information concerning non-melanophores, this chapter focuses on many of the ambiguities and misconceptions concerning these chromatophores. Many of these are concerned with the identification of chromatophores, whereas others, more serious in consequence, relate to errors in the elucidation of data on pigmentary substances. The chapter evaluates investigations that concerns yellow pigment cells (xanthophores), red pigment cells (erythrophores) , and reflecting pigment cells (iridophores). The major part of the discussion concerns amphibians and teleost fishes, but occasional references are made to other cold-blooded vertebrates. Non-melanin-containing chromatophores are dealt with from the standpoints of ontogeny, chemical composition, ultrastructure, and controlling mechanisms. Special attention is devoted to certain aspects of the metabolism of pigments contained in xanthophores, erythrophores, and iridophores. The most reliable diagnostic feature of a chromatophore is its color or general pigmentary appearance. Thus, a yellow pigmmt cell should be called a xanthophore and red pigment cell should be called an erythrophore. In this way, one need not determine whether the pigments are carotenoid, pteridine, flavin, or any mixture of these. With respect to iridophores, it no longer seems feasible to use the term “guanophore,” for here too the character of pigment is variable. With respect to xanthophores and erythrophores, it is now known that pteridines are contained in bodies called pterinosomes, but nothing is known about how this structure is formed or how it is related to other organelles.
Article
Mouse coat colour genes have long been studied as a paradigm for genetic interactions in development. A number of these genes have been cloned and most correspond to human genetic disease loci. The proteins encoded by these genes include transcription factors, receptor tyrosine kinases and growth factors, G-protein coupled receptors and their ligands, membrane proteins, structural proteins and enzymes. Many of the mutations have pleiotropic effects, indicating that these proteins play a wider role in developmental or cellular processes. In this review I tabulate the available data on all pigmentation genes cloned from mouse or human, and I focus on three particular systems. One family of genes, including LYST and HPS/ep, shows the relationship between melanosomes and lysosomes. The G-protein coupled receptor, endothelin receptor-B, and its ligand, endothelin-3, are required for the development of both melanocytes and enteric neurons. The melanocortin-1 receptor is expressed only on melanocytes, but mutations that cause overexpression of agouti protein, an antagonist of the receptor, result in obesity, and highlight a role of melanocortins in weight homoeostasis.
Albinismo em "cobra coral
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Albinismo em "Dorme-dorme
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Amaral, A. (1927b): Albinismo em "Dorme-dorme", Sibynomor phus turgidus (Cope, 1968). -Revista do Museu Paulista, 15: 61-62.
Notas sobre chromatismo de ophidios I. Primeiro caso de erythrismo em serpente, observado no Brasil
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Hoshing, V., S. Thakur & A. Mahabal (2013): Cases of total albinism in Green keelback Macropisthodon plumbicolor and Common wolf snake Lycodon aulicus (Colubridae). -Reptile Rap, 15: 46-47.