(Ctenosaura Bakeri) by a Common

Home , Ctenosaura bakeri, Ctenosaura similis, Green iguana

WWW.IRCF.ORG/REPTILESANDAMPHIBIANSJOURNALTABLE OF CONTENTS IRCF REPTILES & AMPHIBIANSIRCF REPTILES • VOL15, &NO AMPHIBIANS 4 • DEC 2008 189 • 27(1):84–86 • APR 2020

IRCF REPTILES & AMPHIBIANS CONSERVATION AND NATURAL HISTORY

TABLE OF CONTENTS

FEATURE ARTICLES Love. Chasing Bullsnakes Thy (Pituophis catenifer Neighbor: sayi) in Wisconsin: Predation of a On the Road to Understanding the Ecology and Conservation of the Midwest’s Giant Serpent ...... Joshua M. Kapfer 190 Utila .Spiny-tailedThe Shared History of Treeboas (Corallus grenadensis Iguana) and Humans on Grenada: (Ctenosaura bakeri) A Hypothetical Excursion ...... Robert W. Henderson 198 by a RESEARCHCommon ARTICLES Spiny-tailed Iguana (C. similis) . The Texas Horned Lizard in Central and Western Texas ...... Emily Henry, Jason Brewer, Krista Mougey, and Gad Perry 204 . The Knight Anole (Anolis equestris) in Florida ...... on UtilaBrian J. Camposano, Island, Kenneth L. Krysko, Kevin M.Honduras Enge, Ellen M. Donlan, and Michael Granatosky 212

CONSERVATION ALERTDaisy Maryon1,2, Tom W. Brown2, and David C. Lee1 . World’s Mammals in Crisis ...... 220 . More Than Mammals ...... 1University of South Wales, Pontypridd, UK ([email protected])...... 223 . The “Dow Jones Index”2Kanahau of Biodiversity Utila ...... Research and Conservation Facility, Isla de Utila, Honduras ...... 225

HUSBANDRY . Captive Care of the Central Netted Dragon ...... Shannon Plummer 226

he Utila Spiny-tailedPROFILE Iguana (Ctenosaura bakeri; Fig. 1) is Mangroves (Rhizophora mangle) on the island’s southern Ta mangrove specialist. Kraig Adler:endemic A Lifetime to Promoting the island Herpetology of Utila ...... (41 shoreline. Both species wereMichael L.identified Treglia 234 confidently from the km2) in the Islas de Bahia, located off the Caribbean Coast of photographs based on distinct coloration and morphology. COMMENTARY Honduras. The species is listed as Critically Endangered on Prior monitoring at the site provided evidence of spatial over- . The Turtles Have Been Watching Me ...... Eric Gangloff 238 the IUCN Red List (Maryon et al. 2018), due to its small area lap between adults of both species in the transitional beach- of occupancy. PredatorsBOOK of REVIEW this species are known to include front vegetation. Observations suggest that adult C. bakeri . Threatened Amphibians of the World edited by S.N. Stuart, M. Hoffmann, J.S. Chanson, N.A. Cox, birds (Great-tailed Grackle,R. Berridge, herons, P. Ramani, and and egrets;B.E. Young D...... Maryon, dwelling in the mangroves Robert emerge Powell seasonally243 to breed and pers. obs.) and snakes (e.g., the Central American Boa, Boa deposit eggs along the coast (Gutsche 2006; D. Maryon, pers. imperator; Gutsche CONSERVATION2005; Maryon RESEARCH et al., REPORTS: unpubl. Summariesdata). of Publishedobs.). Conservation After hatching,Research Reports juveniles ...... remain 245 in the area for a short  NATURAL HISTORY RESEARCH REPORTS: Summaries of Published Reports on Natural History ...... 247 Ongoing threats include NEWBRIEFS loss and ...... degradation of mangrove period before migrating...... to mangrove 248 habitats. During this habitat, illegal poaching EDITORIAL of adults INFORMATION and eggs, as ...... well as the risk time, juvenile C. bakeri are most...... vulnerable 251 to predation from of hybridization with FOCUS the congeneric ON CONSERVATION Common: A Project Spiny-tailed You Can Support ...... larger C. similis that inhabit and breed 252 in the same area. Iguana (Ctenosaura similis; Pasachnik et al. 2009). Although herbivory is common in iguanids (e.g., Iverson Although Ctenosaura bakeri is a mangrove dwelling spe- 1982), most Spiny-tailed Iguanas (Ctenosaura spp.) have an cies, we have found small populations in recently developed omnivorous diet that includes fruits, invertebrates, and occa- Front Cover. Shannon Plummer. Back Cover. Michael Kern urban areas and coastal habitats usedTotat as etnesting velleseque sitesaudant bymo both sionalTotat vertebrateset velleseque audant (Dirksen mo and Gutsche 2006; Gandola and ctenosaur species. Alberts et al. (2004)estibus inveliquo suggested velique rerchilthat the Hendryestibus inveliquo 2011; velique Pasachnik rerchil and Chavarria 2011). Ctenosaura erspienimus, quos accullabo. Ilibus erspienimus, quos accullabo. Ilibus specialization for mangrove habitatsaut by dolor C. apicto bakeri invere might pe dolum have aut dolor apicto invere pe dolum evolved to avoid competition with thefugiatis larger maionsequat and more eumque aggres - fugiatis maionsequat eumque sive C. similis. Populations of C. similismoditia erere occur nonsedis throughout ma sectiatur moditia erere nonsedis ma sectia- ma derrovitae voluptam, as quos tur ma derrovitae voluptam, as most other habitat types in Utila, accullabo.with the highest population densities in coastal and urban areas (D. Maryon, unpubl. data). It is within these areas where the distributions of the two species often overlap, especially if mangrove fringes are nearby. Although C. similis is larger and more ecologically versatile than C. bakeri (Maryon et al. 2018; Pasachnik 2015), documented interspecific interactions that demonstrate a direct negative effect on C. bakeri remain scarce. Herein we present the first definitive evidence for C. similis preying on C. bakeri. On the morning of 11 June 2017, we photographed a subadult C. similis ingesting a juvenile C. bakeri (Fig. 1). Although we did not witness the capture, the C. similis ingested its prey in under two minutes. The observation Fig. 1. An adult male Utila Spiny-tailed Iguana (Ctenosaura bakeri). took place in beachfront habitat bordering a stand of Red Photograph by Tom W. Brown.

Fig. 2. An adult female Common Spiny-tailed Iguana (Ctenosaura similis). Photograph by Tom W. Brown. similis has been observed consuming Cane Toads (Rhinella Acknowledgements marina; Pasachnik 2011), and C. oedirhina has been observed We are especially grateful to Nancy Hammer who provided eating freshwater turtles (Trachemys sp.) and Green Iguana us with the photographs and to the International Iguana (Iguana iguana) hatchlings (Pasachnik and Chavarria 2011). Foundation and Iguana-Fest for funding our research. We Saurophagy (e.g., consumption of lizards) has been docu- extend this gratitude to all volunteers and members of the mented previously in C. oedirhina (Pasachnik and Chavarria local community who support the “Save the Swamper” 2011) and C. bakeri (Dirksen and Gutsche 2006) and can- iguana campaign and ongoing herpetological research at the nibalism of juveniles has been documented in C. similis, with Kanahau Utila Research & Conservation Facility, Utila. an indication that this may occur more frequently in areas of high density (Mora 1991). Therefore, predation of a conge- Literature Cited Alberts, A.C., R.L. Carter, W.K. Hayes, and E.P. Martins. 2004. Iguanas: Biology ner by C. similis should not be unexpected. Our presented and Conservation. University of California Press, Berkeley, California. observation confirms that C. similis will consume smaller Dirksen, L. and A. Gutsche. 2006. Beobachtungen zur Saurophagie bei Ctenosaura congeneric iguanas if the opportunity arises. Accordingly, bakeri (Squamata: Iguanidae). Elaphe 14(3): 51–52. on Utila, C. similis may not only physically outcompete or Gandola, R. and C. Hendry. 2011. Ctenosaura oedirhina (Roatán Spiny-tailed Iguana). Diet. Herpetological Review 42: 428–429. hybridize with adult C. bakeri in coastal habitats (Pasachnik Gutsche, A. 2005. Ctenosaura bakeri (Utila Spiny-tailed Iguana). Predation. et al. 2009), but their year-round abundance in those regions Herpetological Review 36: 317. may pose a predation risk to migrating juveniles. Gutsche, A. 2006. Population structure and reproduction in Ctenosaura bakeri on

Fig. 3. A subadult Common Spiny-tailed Iguana (Ctenosaura similis) ingesting a juvenile Utila Spiny-tailed Iguana (Ctenosaura bakeri) on Isla de Utila, Islas de Bahia, Honduras. Photographs by Nancy Hammer.

85 MARYON ET AL. IRCF REPTILES & AMPHIBIANS • 27(1):84–86 • APR 2020

Isla de Utila. Iguana 13: 109–115. 2015: e.T174480A73611567. Iverson, J.B. 1982. Adaptions to herbivory in iguanine lizards, pp. 60–76. In: G.M. Pasachnik, S.A. and Z. Chavarria. 2011. Ctenosaura oedirhina (Roatan’s Spiny- Burghardt and A.S Rand (eds.). Iguanas of the World. Their Behavior, Ecology Tailed Iguana). Diet. Herpetological Review 42: 429. and Conservation. Noyes Publications, Park Ridge, New Jersey, USA. Pasachnik, S.A. and J.P. Corneil. 2011. Ctenosaura similis (Black Spiny-Tailed Maryon, D., D. Ardon, A. Martinez, S. Clayson, and S.A. Pasachnik. 2018. Ctenosaura Iguana). Diet. Herpetological Review 42: 601–602. bakeri. The IUCN Red List of Threatened Species 2018: e.T44181A125203850. Pasachnik, S.A., B.M. Fitzpatrick, T.J. Near, and A.C. Echternacht. 2009. Gene Mora, J.M. 1991. Cannibalism in the ctenosaur lizard, Ctenosaura similis, in Costa flow between an endangered endemic iguana, and its wide spread relative, on Rica. Bulletin of the Chicago Herpetological Society 26: 197–198. the island of Utila, Honduras: When is hybridization a threat? Conservation Pasachnik, S.A. 2015. Ctenosaura similis. The IUCN Red List of Threatened Species Genetics 10: 1247–1254.