Turks and Caicos Reptile Checklist Reveals Extinctions and a Single-Island Skink

The Turks and Caicos Islands, a scattering of more than 200 islands and islets at the southeastern tip of the Lucayan Archipelago, are home to a native terrestrial reptile fauna that has just received its most complete accounting to date. A new annotated checklist published in ZooKeys documents 11 native species across eight families, synthesizing published literature through 2026 with nearly two decades of original field data collected across the Turks and Caicos Banks between 2006 and 2025. The result is both a technical reference and a sobering status report: eight of the 11 species are endemic to the territory, and seven are now considered to be of significant conservation concern.

The archipelago’s geography explains much of its biological distinctiveness. The islands sit atop two shallow carbonate platforms, the Turks Bank to the east and the Caicos Bank to the west, separated by the Turks Island Passage, a narrow but deep channel exceeding 2,000 meters that has never been bridged by land. During the last glacial period, roughly 8,000 to 25,000 years ago, both banks stood above sea level as large contiguous landmasses; rising seas since then have fragmented each bank into today’s island configuration. The total land area is only about 500 square kilometers, with a maximum elevation of roughly 50 meters, and the fauna is largely derived from Hispaniola, some 130 kilometers to the south, following ocean currents and hurricane tracks that likely facilitated over-water dispersal.

Among the most alarming findings is the status of the Turks Islands Skink, Spondylurus turksae, assessed as Critically Endangered and now likely restricted to a single population on Cotton Cay, a privately owned island of about 113 hectares. Field surveys between 2008 and 2024 located skinks nowhere else: searches on Grand Turk, Gibbs Cay, Long Cay, Salt Cay, and East Cay all failed, with the most recent survey in March 2024 finding nine individuals on Cotton Cay alone. Barbour noted as early as 1916 that skinks were rare on Grand Turk, suggesting a long decline tied to intensive human land use. The species is morphologically distinguishable from its Caicos Bank congener Spondylurus caicosae by lateral black stripes that continue to the hindlimbs, a higher lamellae count of 211 versus 196, and significant phylogenetic divergence despite their superficial similarity.

The Turks and Caicos Rock Iguana, Cyclura carinata, tells a parallel story of range collapse. The smallest of the nine recognized Cyclura species, with adult males reaching 400 millimeters snout-vent length and 1.2 to 2.8 kilograms, the iguana has been extirpated from 90 percent of its former range, including most major islands. The largest remaining populations, an estimated 15,000 to 20,000 individuals, occur on Big and Little Ambergris Cay at the southeastern edge of the Caicos Bank. Conservation efforts spanning more than 30 years have included cat eradication on Long Cay in 1999, followed by successful reintroduction from Big Ambergris Cay, with juvenile recruitment now observed. Feral cats remain the primary threat, preferentially preying on juveniles and effectively preventing recruitment, while semi-feral goats and donkeys degrade habitat by eliminating ground cover and nesting substrate.

The checklist also delivers a taxonomic correction with nomenclatural weight. Six subspecies of the Turks and Caicos Curlytail, Leiocephalus psammodromus, had been described across the two banks, but molecular genetic analysis of 259 individuals from 13 islands revealed two reciprocally monophyletic lineages, one on each bank, that do not correspond to the morphologically defined subspecies. Acting as First Reviser under ICZN Article 24.2.2, the author gives precedence to L. p. apocrinus for Caicos Bank populations, placing L. p. cacodoxus, L. p. hyphantus, and L. p. mounax as new synonyms, while L. p. psammodromus retains priority for the Turks Bank by date of publication. The species itself, a medium-sized diurnal omnivore that curls its tail upward in social signaling, is assessed as Vulnerable and is considered extirpated from Grand Turk, Salt Cay, South Caicos, and Cotton Cay.

Not all species are in decline. The Turks and Caicos Anole, Anolis scriptus scriptus, the most widely distributed native lizard in the territory, is assessed as Least Concern, thriving in xeric scrub, coppice, tropical dry forest, and urban gardens alike. The species became famous in evolutionary biology when Donihue and colleagues documented rapid, directional morphological selection following Hurricanes Irma and Maria in 2017: post-hurricane survivors on Water Cay and Pine Cay had significantly larger toe pads than pre-hurricane individuals, a heritable trait rather than a plastic response. Two dwarf geckos, Sphaerodactylus caicosensis of the Caicos Bank and S. underwoodi of the Turks Bank, are likewise Least Concern, both small insectivores that tolerate disturbed habitats and human presence, frequently sheltering in building crevices and under surface rocks.

The boa Chilabothrus chrysogaster chrysogaster, endemic to the territory as a subspecies, has become one of the best-monitored reptiles in the Caribbean. Between 2007 and 2025, ongoing surveys marked over 2,500 boas on Big Ambergris Cay, yielding a population estimate of 9,935 plus or minus 740 individuals, a density of roughly 25 boas per hectare. A 20-month radiotelemetry study of 19 adult females showed mean home ranges of 1.83 hectares with substantial overlap. The species is mainly saurophagous, slowly searching rock crevices for sleeping lizards and stalking active prey such as the Caicos Croaking Gecko on rock walls, with large females capable of consuming juvenile rock iguanas up to 1.5 kilograms. Coloration is highly variable, with striped morphs comprising about 15 percent of the Big Ambergris population, and neonates are born orange before transitioning to gray within one to two years.

The Caicos Trope, Tropidophis greenwayi, a small nocturnal constrictor endemic to the Caicos Bank, is assessed as Vulnerable and faces a history of exploitation. The subspecies T. g. greenwayi is restricted to Big Ambergris Cay, where only the two type specimens collected in 1936 were known until an additional individual was found in March 2009; six individuals have been observed between 2010 and 2025. The more widespread T. g. lanthanus is relatively mesophilic, abundant inside the walls of old stone wells where Cuban Treefrogs breed. The species exhibits autohemorrhagy, self-induced bleeding from the mouth, eyes, or cloaca, as a defensive behavior, and was at one time collected for the international pet trade, with a former government official reportedly permitting dealers to remove thousands of individuals from North Caicos.

The pattern that emerges across species and islands is remarkably consistent: populations historically distributed across both banks have been extirpated from islands with long histories of human disturbance and now persist primarily on smaller, more remote cays. The primary driver is the introduction of feral cats and rats, which prey on native reptiles and prevent juvenile recruitment. Habitat loss from development and vehicle mortality represent additional threats, and at least twelve introduced reptilian species are now established or documented, including the tropical house gecko Hemidactylus mabouia, which may competitively displace the endemic Caicos Croaking Gecko, and the Brahminy Blindsnake, which could displace the native Caicos Blindsnake, a fossorial species restricted to the Caicos Bank.

The future of the native herpetofauna will depend on continued enforcement of wildlife protection laws, expansion of feral mammal eradication programs to additional islands with suitable habitat, improved biosecurity at ports of entry to prevent new introductions, and sustained research on species for which basic natural history data remain limited. For the Turks Islands Skink, the recommendations are specific and urgent: removal of rats and any remaining goats on Cotton Cay should be the top conservation priority, followed by establishing additional populations on predator-free islands. Long-term monitoring programs, now spanning over 18 years for the boa and over 30 years for the iguana, provide the baseline data necessary to detect trends and inform management, while growing public awareness through ecotourism and the designation of the rock iguana as a natural symbol of the territory offers a foundation for the conservation action plans these species now require.

Subject of Research: Evolutionary biology

Article Title: An annotated checklist and species accounts of the native terrestrial reptiles of the Turks and Caicos Islands

Article References: Reynolds, R. G. (2026). An annotated checklist and species accounts of the native terrestrial reptiles of the Turks and Caicos Islands. ZooKeys, 1290, 1-33. https://doi.org/10.3897/zookeys.1290.198843

Image Credits: AI Generated

DOI: 10.3897/zookeys.1290.198843

Keywords: Turks and Caicos Islands, reptiles, conservation, endemic species, ZooKeys, herpetology, Caribbean biodiversity, annotated, checklist, species, accounts, native