Current Zoology, 2018, 64(3), 319–320 doi: 10.1093/cz/zoy033 Advance Access Publication Date: 20 April 2018 Letter to the Editor Letter to the Editor Field observations of putative bone-based fluorescence in a gecko John J. SLOGGETT* Maastricht Science Programme, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands *Address correspondence to John J. Sloggett. E-mail: email@example.com Handling editor: Xiang Ji Received on 3 March 2018; accepted on 10 April 2018 Key words: bioﬂuorescence, bone, Chondrodactylus bibronii, Gekkonidae, signaling, Squamata A diversity of animals are biofluorescent, absorbing short- obviously correspond with particular skin elements visible under wavelength electromagnetic radiation, and re-emitting it at longer normal light (compare Figure 1A, B). There appears to be a good wavelengths, giving a distinctive pattern (Lagorio et al. 2015). correspondence with the skull structure of the gecko (e.g., see figures Among terrestrial organisms, biofluorescence has been commonly in Rieppel, 1984). The fluorescence is strongest anteriorly where the recorded in arthropods, but rarely from vertebrates (Lagorio et al. bony covering of the skull is greatest; it is absent from the large eye- 2015). It has long been known from parrots (Hausmann et al. 2003) sockets and at the back of the head where there is no bony covering and has recently been recorded from a frog (Taboada et al. 2017) (Figure 1B, C). In at least one individual, when intensely lit and from chameleons (Chamaeleonidae: Pro ¨ tzel et al. 2018). (Figure 1B) it was also possible to see faint additional fluorescence In their recent paper, Pro ¨ tzel et al. (2018) reported that chame- coincident with skeletal elements in the trunk of the body, notably leon fluorescence is based on the properties of bone visible through the vertebral column, limb-bones, and pelvis, although these were the skin, the first known case of externally visible bone-based fluor- not visible at lower intensities (Figure 1C) and were never as bright escence in vertebrates. They suggest that bone-based fluorescence as the head. could be widespread, especially in other squamates, which often use As these observations were made on live individuals in the field, bony protuberances as ornamentation. I here report a further pos- and anatomical and spectral emission studies were not carried out, sible case of bone-based fluorescence in another squamate group, further work is required to examine this phenomenon in more detail. the geckos (Gekkonidae), discovered accidentally while searching However, despite their limited scope, these observations appear to for scorpions in South Africa using an ultraviolet (UV) light. support Pro ¨ tzel et al. (2018) in their contention that other squa- Bibron’s gecko, Chondrodactylus (¼Pachydactylus) bibronii mates might also possess bone-based fluorescence. Its adaptive value (Smith), is a widespread South African gecko, which is night active, remains open to question, as in some other groups (Lagorio et al. occurring among rocks and also associated with buildings 2015). Geckos use visual displays in part for intraspecific signaling (Barts 2010). During searches at night using a UV torch (CREE Q5, (Marcellini 1977) and in least some species are able to distinguish 395–410 nm wavelength, adjustable focus) around a building in the colors even under night-time conditions (Kelber and Roth 2006). Karoo National Park, South Africa (32.3151 S, 22.3443 E) in early Chondrodactylus bibronii may use signaling to aggregate (Meyer August 2017, this species was observed to exhibit fluorescence. and Mouton 2007), while males are territorial and behave aggres- Pictures were taken of the geckos with and without UV illumination sively toward each other (Barts 2010). Potentially, therefore, UV using a digital camera (Sony Cybershot DSC-HX400V) with a flash fluorescence could serve a number of signaling purposes, but further used for non-UV photos. Illustrative pictures are shown in Figure 1. work is required to confirm or refute this role. Several C. bibronii individuals were observed: although it was not possible to unequivocally identify their life stage or sex, these Acknowledgments included larger individuals presumed to be adults. The head was quite strongly UV fluorescent anteriorly (Figure 1B, C), extending I thank Thomas Cleij for his Sinterklaas gift of the UV torch, without which it behind the eyes. The florescence did vary in its intensity but did not would not have been possible to make these observations. V C The Author(s) (2018). Published by Oxford University Press. 319 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact firstname.lastname@example.org Downloaded from https://academic.oup.com/cz/article-abstract/64/3/319/4979555 by Ed 'DeepDyve' Gillespie user on 21 June 2018 320 Current Zoology, 2018, Vol. 64, No. 3 References Barts M, 2010. Dickﬁngergeckos: Pachydactylus turneri & Pachydachtylus bibronii. Mu ¨ nster, Germany: Natur und Tier-Verlag. Hausmann F, Arnold KE, Marshall NJ, Owens IPF, 2003. Ultraviolet signals in birds are special. Proc R Soc Lond B 270:61–67. Kelber A, Roth LSV, 2006. Nocturnal colour vision – not as rare as we might think. J Exp Biol 209:781–788. Lagorio MG, Cordon GB, Iriel A, 2015. Reviewing the relevance of ﬂuores- cence in biological systems. Photochem Photobiol Sci 14:1538–1559. Marcellini D, 1977. Acoustic and visual display behavior of gekkonid lizards. Am Zool 17:251–260. Meyer A, le Fras N. Mouton P, 2007. Aggregation in Bibron’s gecko Chondrodactylus bibronii. Afr J Herpetol 56:137–147. Pro ¨ tzel D, Heß M, Scherz MD, Schwager M, van’t Padje A et al., 2018. Widespread bone-based ﬂuorescence in chameleons. Sci Rep 8:part 698. Rieppel O, 1984. The structure of the skull and jaw adductor musculature in the Gekkota, with comments on the phylogenetic relationships of the Xantusiidae (Reptilia: Lacertilia). Zool J Linn Soc 82:291–318. Taboada C, Brunetti AE, Pedron FN, Carnevale Neto F, Estrin DA et al., 2017. Naturally occurring ﬂuorescence in frogs. Proc Natl Acad Sci USA 114:3672–3677. Figure 1. Three views of C. bibronii under normal light and UV (395–410 nm wavelength) light. (A) Under normal light (camera ﬂash). (B) The same gecko under intense UV light (focused beam) showing the strongly ﬂuorescent head elements and ﬂuorescent trunk elements (arrowed, I and II). (C) The same gecko again under more diffuse UV light, with just the head ﬂuorescing. Downloaded from https://academic.oup.com/cz/article-abstract/64/3/319/4979555 by Ed 'DeepDyve' Gillespie user on 21 June 2018
Current Zoology – Oxford University Press
Published: Apr 20, 2018
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