Spectral reflectance and substrate color-induced melanization in immature and adult Midland painted turtles (Chrysemys picta marginata)

Rowe, John W.; Bunce, Charles F.; Clark, David L.

doi:10.1163/15685381-00002934

Cited by 8 publications

(9 citation statements)

References 28 publications

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“…The fact that both species of turtles also have a light plastron, but a dark coloured carapace is consistent with the hypothesis that the increased reflectance caused by the presence of iridophores on the ventral side of the head might serve a camouflage function. The background head coloration (DHC), which has been previously reported to change in response to substrate colour [37,92–94], is produced in both T. scripta and P. concinna by epidermal melanosomes and a combination of all three dermal pigment cell types (figure 7 e , f ). However, we found epidermal melanocytes in the PM of both lineages of T. scripta (figures 4 and 8 a–c ), but not in the PM of P. concinna (figures 5 and 8 e , f ) or in other yellow regions of the examined turtles (figure 7 b , d ).…”

Section: Discussionmentioning

confidence: 99%

Body coloration and mechanisms of colour production in Archelosauria: the case of deirocheline turtles

et al. 2019

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Animal body coloration is a complex trait resulting from the interplay of multiple mechanisms. While many studies address the functions of animal coloration, the mechanisms of colour production still remain unknown in most taxa. Here we compare reflectance spectra, cellular, ultra- and nano-structure of colour-producing elements, and pigment types in two freshwater turtles with contrasting courtship behaviour, Trachemys scripta and Pseudemys concinna . The two species differ in the distribution of pigment cell-types and in pigment diversity. We found xanthophores, melanocytes, abundant iridophores and dermal collagen fibres in stripes of both species. The yellow chin and forelimb stripes of both P. concinna and T. scripta contain xanthophores and iridophores, but the post-orbital regions of the two species differ in cell-type distribution. The yellow post-orbital region of P. concinna contains both xanthophores and iridophores, while T. scripta has only xanthophores in the yellow-red postorbital/zygomatic regions. Moreover, in both species, the xanthophores colouring the yellow-red skin contain carotenoids, pterins and riboflavin, but T. scripta has a higher diversity of pigments than P. concinna . Trachemys s. elegans is sexually dichromatic. Differences in the distribution of pigment cell types across body regions in the two species may be related to visual signalling but do not match predictions based on courtship position. Our results demonstrate that archelosaurs share some colour production mechanisms with amphibians and lepidosaurs (i.e. vertical layering/stacking of different pigment cell types and interplay of carotenoids and pterins), but also employ novel mechanisms (i.e. nano-organization of dermal collagen) shared with mammals.

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Section: Discussionmentioning

confidence: 99%

Body coloration and mechanisms of colour production in Archelosauria: the case of deirocheline turtles

et al. 2019

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Section: Discussionmentioning

confidence: 99%

“…The coloration of deirocheline turtles is thought to play a role in mate choice [30,34]. Some species are sexually dichromatic, with males often displaying the brightest, most conspicuous colours (reviewed in [19]); however sexual dichromatism is limited to particular regions of the body, whereas other regions show no sexual differences [35,36]. Colour ornaments are designed to maximize their conspicuousness only in certain, ecologically relevant contexts [37], e.g.…”

Section: Introductionmentioning

confidence: 99%

Body coloration and mechanisms of colour production in Archelosauria: The case of deirocheline turtles

Brejcha

Bataller

Bosáková

et al. 2019

Preprint

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21Animal body coloration is a complex trait resulting from the interplay of multiple colour-producing mechanisms. 22Increasing knowledge of the functional role of animal coloration stresses the need to study the proximate causes of 23 colour production. Here we present a description of colour and colour producing mechanisms in two non-avian 24 archelosaurs, the freshwater turtles Trachemys scripta and Pseudemys concinna. We compare reflectance spectra; 25 cellular, ultra-, and nano-structure of colour-producing elements; and carotenoid/pteridine derivatives contents in 26 the two species. In addition to xanthophores and melanocytes, we found abundant iridophores which may play a 27 role in integumental colour production. We also found abundant dermal collagen fibres that may serve as 28 thermoprotection but possibly also play role in colour production. The colour of yellow-red skin patches results from 29 an interplay between carotenoids and pteridine derivatives. The two species differ in the distribution of pigment cell 30 types along the dorsoventral head axis, as well as in the diversity of pigments involved in colour production, which 31 may be related to visual signalling. Our results indicate that archelosaurs share some colour production mechanisms 32 with amphibians and lepidosaurs, but also employ novel mechanisms based on the nano-organization of the 33 extracellular protein matrix that they share with mammals. 34 35 *Jindřich Brejcha 2 36 65 Turtles are an early-diverging clade of Archelosauria, the evolutionary lineage of tetrapods leading to 66 crocodiles and birds [22]. Although many turtles have a uniform dull colour, conspicuous striped and spotted 67 patterns are common in all major lineages of turtles (for a comprehensive collection of photographs see [23-26]).68 These conspicuous colour patterns may be present in the hard-horny skin of shells, and/or in the soft skin of the 69 head, limbs or tail. The dark areas of the skin of turtles may have a threefold origin consisting either of dermal, 70 epidermal, or both epidermal and dermal melanocytes. Colourful bright regions are thought to be the result of the 71 presence of xanthophores in the dermis [27] and their interplay with dermal melanophores [28]. Iridophores have 72 never been shown to play role in coloration of turtles [27,29]. 73Pigment-bearing xanthophores were first described in the dermis of the Chinese softshell turtle (Pelodiscus 74 sinensis) [29]. Xanthophores have also been found sporadically in the dermis of the spiny softshell turtle Apalone 75 spinifera, the Murray river turtle (Emydura macquarii) and in the painted turtle (Chrysemys picta) [27]. Such scarcity 76 3 of carotenoid/pteridine derivatives-containing cells is in contrast with chemical analyses of the yellow and red 77 regions of the integument of the red-eared slider (Trachemys scripta elegans) and C. picta [30,31]. Two major 78 classes of carotenoids have been described in the integument of these turtles: short wavelength absorbing 79 apocarotenoids and longer wave...

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“…Many reptiles will match their body coloration to habitat environments, including turtles (Hall, Robson, & Ariel, 2018;McGauch, 2008;Rowe, Bunce, & Clark, 2014;Rowe, Miller, et al, 2014;Xiao et al, 2016), snakes (Rajabizadeh, Adriaens, Kaboli, Sarafraz, & Ahmadi, 2015), gecko (Vroonen, Vervust, Fulgione, Maselli, & Damme, 2012), and lizards (Corl et al, 2018;Hamilton et al, 2008;Krohn & Rosenblum, 2016;Stuart-Fox, Moussalli, & Whiting, 2008;Tao et al, 2018). These animals can adapt to varied substrate coloration in physiological and/or morphological color change.…”

Section: Introductionmentioning

confidence: 99%

“…We observed the dorsal coloration of P. versicolor distributed only at dark substrate in Liuyuan town (Gansu province) is visibly darker (melanic, see Figure a) than other conspecific populations (nonmelanic, see Figure a) living in weathered yellow (light) substrate. In this study, spectrometry technology (Matthews, Goulet, Delhey, & Chapple, ; Rowe, Bunce, & Clark, ; Rowe, Miller, et al, ) and digital photography (McGauch, ; McKay, ; Stevens, Parraga, Cuthill, Partridge, & Troscianko, ) were used to quantify the natural dorsal color variation and their native substrate color difference between melanic and nonmelanic P. versicolor populations, aiming to determine: (a) whether the color properties of melanic and nonmelanic lizards differed significantly; (b) whether the dorsal color properties from different habitats were associated with the different color substrates (i.e., black and weathered yellow sand), which could suggest background matching camouflage; and (c) whether each lizard color morph displays a behavioral preference for substrates that match their body coloration.…”

Section: Introductionmentioning

confidence: 99%

Effects of substrate color on intraspecific body color variation in the toad‐headed lizard, Phrynocephalus versicolor

Tong

et al. 2019

Ecology and Evolution

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Diversity in animal coloration is generally associated with adaptation to their living habitats, ranging from territorial display and sexual selection to predation or predation avoidance, and thermoregulation. However, the mechanism underlying color variation in toad‐headed Phrynocephalus lizards remains poorly understood. In this study, we investigated the population color variation of Phrynocephalus versicolor. We found that lizards distributed in dark substrate have darker dorsal coloration (melanic lizards) than populations living in light substrates. This characteristic may improve their camouflage effectiveness. A reciprocal substrate translocation experiment was conducted to clarify the potential role of morphological adaptation and physiological plasticity of this variation. Spectrometry technology and digital photography were used to quantify the color variation of the above‐mentioned melanic and nonmelanic P. versicolor populations and their native substrate. Additionally, substrate color preference in both populations was investigated with choice experiments. Our results indicate that the melanic and nonmelanic populations with remarkable habitat color difference were significantly different on measured reflectance, luminance, and RGB values. Twenty‐four hours, 30 days, and 60 days of substrate translocation treatment had little effects on dorsal color change. We also found that melanic lizards choose to live in dark substrate, while nonmelanic lizards have no preference for substrate color. In conclusion, our results support that the dorsal coloration of P. versicolor, associated with substrate color, is likely a morphological adaptation rather than phenotypic plasticity.

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Spectral reflectance and substrate color-induced melanization in immature and adult Midland painted turtles (Chrysemys picta marginata)

Cited by 8 publications

References 28 publications

Body coloration and mechanisms of colour production in Archelosauria: the case of deirocheline turtles

Body coloration and mechanisms of colour production in Archelosauria: the case of deirocheline turtles

Body coloration and mechanisms of colour production in Archelosauria: The case of deirocheline turtles

Effects of substrate color on intraspecific body color variation in the toad‐headed lizard, Phrynocephalus versicolor

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