Herpetology Notes, volume 11: 601-602 (2018) (published online on 04 August 2018)

Axanthism in the Southern Leopard Frog, Lithobates sphenocephalus (Cope, 1886), (Anura: Ranidae) from the state of Tennessee, USA

Emily M. Hall1, Louise A. Rollins-Smith1,2, and Brian T. Miller3,*

Blue or partially blue colour variants have been on Arnold Air Force Base (AAFB) in Franklin County, reported for several species of frogs, especially in the Tennessee, USA. We recaptured this frog at the same family Ranidae (Jablonski et al., 2014). An aberrant pond on 13 October 2017. The frog had the spotting blue colouration in frogs presumably is associated pattern characteristic of the species, but the dorsum with genetic mutations of the carotenoid-bearing was almost entirely pale blue, with only a few small, xanthophores (Berns and Narayan, 1970; Bechtel, 1995; scattered patches of green. Although small patches of Henle et al., 2017). Normally, underlying iridiphores blue were present also on the sides, snout, upper thighs, reflect short (blue) wavelengths of light back through and calves, much of the body was normally coloured. yellowish carotenoids in overlying xanthophores, The irises were a pale golden-yellow. which results in the greenish colouration typical of The partially axanthic individual was one of 12 L. many species of frogs (Bagnara et al., 1968; Bagnara sphenocephalus we found at the pond during September, and Hadley, 1973; Bagnara and Matsumoto, 2006). If one of 16 we found at the pond during 2017, and one xanthophores are lacking or do not properly sequester of 164 that we found at AAFB during 2017. Although carotenoids, short wavelengths of light reflect back colouration is variable among L. sphenocephalus in through the skin unaltered, which results in a patch middle Tennessee in general and at Arnold Air Force that appears blue (Berns and Narayan, 1970; Bechtel, 1995). Such aberrant blue colouration can occur either over the entire body surface or as scattered isolated patches (partial axanthism). In this report, we describe an axanthic Southern Leopard Frog, Lithobates sphenocephalus (Cope, 1886) from middle Tennessee in the southeastern USA. On 29 September 2017 at approximately 20:00 h, we found a partially axanthic adult male L. sphenocephalus (TL = 54.6 mm; mass = 14.2 g; Figure 1) at a small pond (35.343289oN, 86.129559oW; WSG84) located

1 Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA. 2 Department of Biological Sciences, Vanderbilt University, Figure 1. A partially axanthic adult male Southern Leopard Nashville, Tennessee 37235, USA. Frog, Lithobates sphenocephalus, initially captured on 29 3 Department of Biology, Middle Tennessee State University, September 2017 and recaptured on 13 October 2017 at Arnold Murfreesboro, Tennessee 37132, USA. Air Force Base in northern Franklin County, Tennessee, USA. * Corresponding author. E-mail: [email protected] (Photograph by Brian T. Miller) 602 Emily M. Hall et al.

clamitans, and L. sphenocephalus), and reports in this region are limited to one axanthic L. catesbeianus from Kentucky, one axanthic L. clamitans from Virginia, and one axanthic L. sphenocephalus from Georgia (Martof, 1962; Berns and Uhler, 1966). Jablonski et al. (2014) suggest that the disparity in frequency of occurrence of axanthism among species and regions could be an artefact associated with differences in the intensity of herpetological research in different countries. We agree with this assessment, but are not able to explain the low frequency of axanthism reported for ranid species in the southeastern United States, which is an area of intensive herpetological investigation. Regardless, we agree with Figure 2. An adult female Southern Leopard Frog, Lithobates Jablonski et al. (2014) who state that “axanthism is an sphenocephalus, from Arnold Air Force Base in southern interesting colour aberration of amphibians that deserves Coffee County, Tennessee, USA depicting the typical green more attention”. colouration of the snout, legs, sides, and dorsum. (Photograph by Brian T. Miller) Acknowledgements. This work was funded in part by the Department of Defense SERDP (Strategic Environmental Research and Development Program) Contract W912HQ-16-C- 0033, Corinne Richards-Zawacki, P.I., subcontract awarded to Louise Rollins-Smith. Base in particular, the back and sides of most individuals from these regions are washed a vivid green (Figure 2). References This is the first report of an axanthic L. sphenocephalus from Tennessee and only the second report of this Bagnara, J.T., Taylor, J.D., Hadley, M.E. (1968): The dermal aberrant colouration for the species. The first report chromatophore unit. The Journal of Cell Biology 38: 67–79. occurred during the early 1960s when Martof (1962) Bagnara, J.T., Hadley, M.E. (1973). Chromatophores and Color Change. The Comparative Physiology of Animal Pigmentation, described an axanthic L. sphenocephalus (referred to Englewood Cliffs, USA, Prentice-Hall. d then as Rana pipiens) from Sapelo Island, Georgia, Bagnara, J.T., Matsumoto, J. (2006). ����������������������� USA. physiology of pigment cells in non-mammalian tissues. In: Axanthism is reported more often in frogs from North The Pigmentary System, p. 11–59. 2nd Edition, Nordlund, J.J., America than from other regions of the world (Jablonski Boissy, R.E., Hearing, V.J., King, R.A., Oetting, W.S., Ortonne, et al., 2014), and in North America blue frogs are J.-P. Eds., Oxford, UK, Blackwell Publishing Ltd. reported more often from northern than from southern Bechtel, H.B. (1995): Reptile and Amphibian Variants: Colors, Patterns, and Scales, Malabar, USA, Krieger Publishing populations (Berns and Uhler, 1966). Furthermore, Company. d axanthism apparently occurs more frequently in some Berns, M.W., Narayan, K.S. (1970): �������������������� species of ranid frogs with large distributions, including ultrastructural analysis of the dermal chromatophores of the the Green frog, L. clamitans (Latreille, 1801), than variant blue frog. Journal of Morphology 132: 169–180. in other species, such as the American bullfrog, L. Berns, M.W., Uhler, L.D. (1966): Blue frogs of the genus Rana. catesbeianus (Shaw, 1802) and the Northern leopard Herpetologica 22: 181–183. frog, L. pipiens (Schreber, 1782) (Berns and Uhler, Henle, K., Dubois, A., Vershinin, V. (2017): Commented glossary, terminology and synonymies of anomalies in natural populations 1966). Lastly, axanthism apparently is rare in species of of amphibians. Mertensiella 25: 9–48. ranid frogs in the southeastern United States (Jablonski Jablonski, D., Alena, A., Vlček, P., Jandzik, D. (2014): Axanthism et al., 2014). For example, although more than 100 in amphibians: A review and the first record in the wide-spread axanthic L. clamitans have been reported, only one of toad of the Bufotes viridis complex (Anura: Bufonidae). Belgian these is from the southeastern United States, with most Journal of Zoology 144: 93–101. reports from the northeastern and northcentral regions Martof, B.S. (1962): An unusual color variant of Rana pipiens. of the country (Berns and Uhler, 1966). Based on the Herpetologica 17: 269–270. summary provided by Jablonski et al. (2014), axanthism has been reported for only three species of ranid frogs Accepted by Gonçalo Rosa in the southeastern United States (L. catesbeianus, L.