Herpetology Notes, volume 13: 483-484 (2020) (published online on 03 June 2020)

Regenerate tail bifurcation in the Green Iguana (Iguana iguana Linnaeus, 1758)

Julián Arango-Lozano1,* and Dahian Patiño-Siro

Tail bifurcation is a relatively frequent anomaly Hermosa (6.4644°N; -75.7596°W), municipality of San already recorded in a number of lizard families, Jerónimo, Antioquia department, in the central Andes of including Iguanidae (e.g., Ananjeva and Danov, 1991; Colombia. The site consisted of gallery forest comprised Conzendey et al., 2013; Martins et al., 2013; Pheasey mostly of two tree species (Melicoccus bijugatus et al., 2014; Koleska et al., 2017); this anomaly is Jacquin, 1760 and Mangifera indica Linnaeus, 1753). usually associated with a failure in the process of tail The forest was bordered on one side by a small river regeneration following caudal autotomy, as opposed to (the Aurrá River) with a highway on the other side. Tail congenital malformations arising during development bifurcation in this female started at approximately 45 cm (Conzendy et al., 2013). The presence of two or even post-cloaca (Figure 1A). The longest tail measured 29 more tails generally occurs when the tail is damaged cm (Figure 1B) and presented a secondary regeneration but is not completely autotomized; at this point an of this tail at 14.5 cm (Figure 1D). The shorter tail additional tail (or tails) begins to develop (Ananjeva measured 13 cm and had a fresh injury at its tip (Figure and Danov, 1991). 1C). Despite this anomaly, the female seemed to be in The detachment of a part of the tail in lizards not only good condition. After measuring and photographing the occurs to escape predation, it also can be the result of female, she was released at her capture site. intraspecific aggression during mating and territorial We hypothesize that the tail bifurcation in this female fights (Iverson et al., 2004; Koleska et al., 2017). The I. Iguana was the result of a complete caudal autotomy, ability to regenerate the tail in lizards shows that it is rather than a case of incomplete autotomy (Ananjeva an important organ (for storing nutrients, maintaining and Danov, 1991; Pheasey et al., 2014), because both balance, and in overcoming obstacles during locomotion, tails originated separately at the same starting point Iverson et al., 2004). (injury point, Figure 1A). It is possible that when the tail The Green Iguana (Iguana iguana Linnaeus, 1758) is a diurnal, arboreal lizard in the family Iguanidae with a wide distribution from southeastern Mexico through Central America to southeastern Brazil and Paraguay; it is also present in some of the Caribbean islands and has been introduced in many locations outside of its natural range (Etheridge, 1982; Savage, 2002). Females are smaller than males of the same age, with males growing up to 2 meters in total length, but in both sexes the tail can make up approximately half of the total length (Savage, 2002; Bock, 2013). On March 4 2019 at 10:00, we observed and captured an adult female I. iguana during a field trip in Loma

Figure 1. Adult female Iguana iguana, with a tail bifurcation, 1 Programa de Biología, Universidad del Quindío, Colombia. captured in the Central Andes of Colombia (Photo by Julián * Corresponding author Email: [email protected] Arango-Lozano). See text for explanations of A-D. 484 Julián Arango-Lozano & Dahian Patiño-Siro was autotomized, the damage triggered the regeneration Martins, R.L., Peixoto, P.G., Fonseca, P.H., Martinelli, A.G., Silva, process and the first tail started to grow, but then, a new W.R., Pelli, A. (2013): Abnormality in the tail of the collated injury occurred in the starting point and triggered a lizard Tropidurus gr. torquatus (Iguania, Tropiduridae) from Uberaba city, Minas Gerais State, Brazil. Herpetology Notes 6: second regeneration process of another regenerate tail. 369–371. Although the tail is an important structure for lizards, Passos, D.C., Pinheiro, L.T., Galdino, C.A.B., Rocha, C.F.D. in arboreal species such as I. iguana it may be even more (2014): Tropidurus semitaeniatus (Calango de Lagedo). Tail important, since the presence of the tail affects the centre Bifurcation. Herpetological Review 45: 138. of balance by acting as a counterbalance while moving Pheasey, H., Smith, P., Brouard, J.P., Atkinson, K. (2014): (or jumping) through vegetation (Losos, 1990; 2011); Vanzosaura rubricauda (Red-tailed Vanzosaur). Bifurcation and trifurcation. Herpetological Review 45: 138–139. also, the presence of multiple tails in a Green Iguana Savage, J.M. (2002): The Amphibians and Reptiles of Costa Rica: individual could affect its fitness in negative ways, A Herpetofauna between Two Continents, Between Two Seas. because the tail is necessary for locomotion activities Chicago, Illinois, University of Chicago Press. such as foraging, mating, and escaping predators (Maria and Al-Razi, 2018; Passos et al., 2014). It is surprising that, since I. iguana is a species so well studied, tail bifurcation has not been reported previously; this note is the first to address the phenomenon in this species.

Acknowledgements. We thank Arce Modern Gardens S.A.S. for helping us with logistics while in field, and to Dr. Brian C. Bock for his multiple suggestions in previous versions of this manuscript.

References

Ananjeva, N.B., Danov, R.A. (1991): A rare case of bifurcated caudal regeneration in the Caucasian agama, Stellio caucasius. Amphibia-Reptilia 12: 343–349. Bock, B.C. (2013): Iguana iguana (Linnaeus 1758). In: Catálogo de Anfibios y Reptiles de Colombia 1: 10–14. Conzendey, P., Campos, S.P.S., Lanna, F.M., De Amorim, J.D.C.G., De Sousa, B.M. (2013): Ophiodes striatus (Striped Worm Lizard). Bifurcated tail. Herpetological Review 44: 145–146. Etheridge, R.E. (1982): Checklist of the iguana and Malagasy iguanids. In: Iguanas of the World: Their Behavior, Ecology and Conservation, p. 7–37. Burghardt, G.M; Rand, A.S., Eds., Noyes, New Jersey: Park Ridge. Iverson, J.B., Smith, G.R., Pieper, L. (2004): Factors affecting long- term growth of the Allen Cays rock iguana in the Bahamas. In: Iguanas: Biology and Conservation, p. 176–192. Alberts, A.C; Carter R.L; Hayes W.K; Martins E.P., Eds., Berkeley, USA, University of California Press. Koleska, D., Svobodova, V., Husák, T., Kulma, M., Jablonski, D. (2017): Tail bifurcation recorded in Sauromalus ater. Herpetology Notes 10: 363–364. Losos, J.B. (1990): The evolution of form and function: morphology and locomotor performance in West Indian Anolis lizards. Evolution 44: 1189–1203. Losos, J.B. (2011): Form, Function, and Adaptive Radiation. In: Lizards in an evolutionary tree: Ecology and adaptive radiation of anoles, p. 257–290. Berkeley, USA, University of California Press. Maria, M., Al-Razi, H. (2018): Observation of tail bifurcation in Accepted by Graham Walters Hemidactylus frenatus (Schlegel, 1836). Herpetology Notes 11: 953–954.