INTRODUCTION

The Black-chested Spiny-tailed Iguana, Ctenosaura
melanosterna (Buckley and Axtel 1997), is a mediumsized,
spiny-tailed iguana, and a member of the C.
palearis clade. The group consists of four narrow-range
endemics (C. palearis, C. oedirhina, C. bakeri, and C.
melanosterna; Pasachnik et al. 2010) occurring in
Guatemala and Honduras. Two distinct evolutionarily
significant units (ESUs) have been described for C.
melanosterna (Pasachnik et al. 2011). One occurs
within the arid tropical scrub forest of the Valle de
Aguán, Honduras, and the other occurs primarily on two
islands (Cayo Menor and Cayo Mayor) within the Cayos
Cochinos Archipelago, Honduras. Overall the species is
listed as Endangered by the IUCN Redlist Assessment, is
listed on Appendix II of CITES, and has been
recognized as one of the top four most vulnerable
species in Honduras (Wilson and McCranie 2004). Each
ESU is listed as Critically Endangered based on differing
causes. Factors associated with an extremely restricted
range threaten the Cayos Cochinos ESU, whereas the
mainland ESU is threatened primarily by habitat
destruction and overharvesting (IUCN. 2011. IUCN Red
List of Threatened Species, Version 2011.2. Available
from www.iucnredlist.org [Accessed 01 September
2011).
Substantial variation exists between, and in some
cases, within, the mainland and the island regions in
terms of types and degrees of threats present and the
level of protection afforded. The Cayos Cochinos ESU
is within the Cayos Cochinos Archipelago Natural
Marine Reserve (CCANMR) administered by the
Honduran Coral Reef Foundation (HCRF). Thus, both
Cayo Menor and Cayo Mayor are technically protected;
however, Cayo Menor is more actively protected
because of the presence of personnel associated with the
HCRF research station. The iguana populations on both