© Firenze University Press www.fupress.com/ah Acta Herpetologica 5(1): 87-89, 2010 Unusual colour form of Siberian pit viper (Gloydius h. halys) from the northern edge of its area Evgeniy Simonov Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Science, Frunze 11, 630091 Novosibirsk, Russia. E-mail: ev.simonov@gmail.com Submitted on: 2009, 28th August. Revised on: 2010, 21st April. Accepted on 2010, 30th April. Abstract. In this report, I describe the unusual colour form of Siberian pit viper (Gloydius h. halys) from the marginal population in Novosibirsk region (West Siberia, Russia). This morph was named “bronze” and occurs of 16% of individuals. To the best of my knowledge, such colour pattern does not known from other parts of G. halys area. Keywords. Pit viper, Gloydius halys, “bronze” pattern. Diverse colour patterns of Squamates perform different important functions: ther- moregulation, predators avoidance, mimicry, crypsis, protection of vital organs, and some other (Jackson et al., 1976; Sweet, 1985; Brodie, 1993; Brodie and Janzen, 1995; Tanaka, 2005). Within one species various colour forms (morphs) may reflect local adaptations to a given stimulus. For instance an increase of dark (melanistic) individuals may be affected by non-optimal thermal conditions as dark coloured individuals have some advantages for thermoregulation (e.g., Tanaka, 2005). On the other hand, proportion of different morphs may be influenced by random genetic drift (e.g., Bittner and King, 2003). The Halys pit viper [Gloydius halys (Pallas, 1776)] is the most widespread species of the subfamily Crotalinae with 6 to 9 recognised subspecies (Orlov and Barabanov, 1999; Uetz and Hallermann, 2009). Since 2006, I have been carrying out on ecological and mor- phological research on this species in the southeastern part of Novosibirsk region (West Siberia, Russia) in the valley of river Berd’. A detailed description of study area is provided in Simonov (2009). This locality represents the isolated northwesternmost point of Halys pit vipers’ distribution. Nearest neighbour populations are between 190 and 250 km dis- tance (Simonov, 2008). During four years, 106 individuals of G. h. halys (except neonates) were captured and examined. To avoid repeated measurements, I used individual recogni- tion of head coloration patterns combined with clipping of ventral scales. Most of pit vipers in this population have a typical colour pattern, but 16% (n = 17) of snakes have a reduced band pattern. These individuals have a uniform color of brown- 88 E. Simonov ish tints covering dorsal and lateral parts of body, whereas head and ventral side display common pattern (Fig. 1). Some of them have a light or dark narrow vertebral strip and/or dotted lateral strips (Table 1). In addition, all abnormal coloured snakes have a light marks on the nape of the neck. This morph was named “bronze”, as Nilson et al. (1995) named very similar colour form encountered among Vipera dinniki and Vipera lotievi. Within G. h. halys the “bronze” morph occurs in both sexes, but it was also met in one juvenile snake. Although the Halys pit viper is a very polymorphic species, individuals without typi- cal banded pattern are very rare. Occurrences of completely black and red individuals of G. halys are known from Kirghizia and south Kazakhstan (Yakovleva, 1964; Kolbincev, 2006). Pestov (2003), who first discovered the considered population of G. halys, shortly mentioned the encounter of two “monotonous brown” specimens. Besides it, no addition- Fig. 1. Bronze colour form (A) and normal colour pattern (B) of Gloydius halys halys from Novosibirsk region. Table 1. Frequencies of Siberian pit viper (G. h. halys) colour forms in examined population from Novosi- birsk region. Colour form Frequency, n (%) Normal 89 (84%) Bronze (uniform) 10 (9.4%) Bronze (striped) 7 (6.6%) Bronze (total) 17 (16%) 89Unusual colour form of Siberian pit viper al records about bronze, not banded, individual snakes, apart those presently described, are available to date. REFERENCES Bittner, T.D., King, R.B. (2003): Gene flow and melanism in garter snakes revisited: a com- parison of molecular markers and island vs. coalescent models. Biol. J. Linn. Soc. 79: 389-399. Brodie, E.D. III (1993): Differential avoidance of coral snake banded patterns by free- ranging avian predators in Costa Rica. Evolution 47: 227-235. Brodie, E.D. III, Janzen, F.J. (1995): Experimental studies of coral snake mimicry: general- ized avoidance of ringed snake patterns by free-ranging predators. Funct. Ecol. 9: 186-190. Jackson, F.J., Ingram, W. III, Campbell, H.W. (1976): The dorsal pigmentation pattern of snakes as an antipredator strategy: a multivariate approach. Am. Nat. 110: 1029- 1053. Kolbincev, V.G. (2006): Amphibians and reptiles of Aksu-Djabagly reserve and features of its ecology. Selevinia 2006: 160-172. [in Russian] Nilson, G., Tuniyev, B.S., Orlov, N., Höggren, M., Andrén, C. (1995): Systematics of the Vipers of the Caucasus: polymorphism or sibling species? Asiatic Herpetol. Res. 6: 1-26. Orlov, N.L., Barabanov, A.V. (1999): Classification of the Agkistrodon halys-intermedius complex: a critical review. Rus. J. Herpetol. 6: 167-192. Pestov, M.V. (2003): Halys pit viper – the new species of Novosibirsk region’s fauna. In: Amphibians and reptiles in West Siberia, p. 35-38. “Revi-K” Press, Novosibirsk. [in Russian] Simonov, E.P. (2008): Revision of north distribution’s board of Halys pit viper (Gloydius (Agkistrodon) halys) and its biotopical location on West Siberia territory. Bull. Mor- dovia Univ., Biol. Sci. 2: 65-70. [in Russian] Simonov, E.P. (2009): Differences in habitat use, daily activity patterns and preferred ambient temperatures of adult and neonate Gloydius halys halys from an isolated population in southwest Siberia: preliminary data. Herpetol. Notes 2: 1-7. Sweet, S.S. (1985): Geographic variation, convergent crypsis and mimicry in gopher snakes (Pituophis melanoleucus) and western rattlesnakes (Crotalus viridis). J. Her- petol. 19: 55-67. Tanaka, K. (2005): Thermal aspects of melanistic and striped morphs of the snake Elaphe quadrivirgata. Zool. Sci. 22: 1173-1179. Uetz, P., Hallermann, J.: The Reptile Database, http://www.reptile-database.org, accessed 23 August 2009. Yakovleva, I.D. (1964): Reptiles of Kirghizia. Frunze. [in Russian]