The Acklins ground iguana (''Cyclura rileyi nuchalis''), also commonly known as the Watling Island iguana, is an endangered

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

of the genus '' Cyclura'' it is one of three subspecific forms of ''

Cyclura rileyi ''Cyclura rileyi'', Common name, commonly known as the Bahamian rock iguana or the San Salvador rock iguana, is a critically endangered species of lizard in the Family (biology), family Iguanidae. The species is native to three island groups in ...

'' in the family Iguanidae.

Taxonomy

The Acklins ground iguana is a recognized subspecies of the San Salvador rock iguana, recognized as such since 1975. Its specific name, ''rileyi'', is a Latinized form of the name of American

biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual Cell (biology), cell, a multicellular organism, or a Community (ecology), community of Biological inter ...

Joseph Harvey Riley Joseph Harvey Riley (September 19, 1873 – December 17, 1941) was an American ornithologist. Born in Falls Church, Virginia, Riley was employed at the Smithsonian Institution from 1896 until his death, becoming Associate Curator of the Division of ...

Anatomy and morphology

The Acklins ground iguana strongly resembles the San Salvador rock iguana in color and shape. The lizard's back color can range from red, orange or yellow, to green, brown or grey, usually patterned by darker markings. The very brightest colors (red, orange or yellow) are normally only displayed by males and are more pronounced which at warmer body temperatures. Immature iguanas lack these bright colors, being either solid brown or grey with faint slightly darker stripes. What makes this iguana stand out from the other two subspecies is the scalation on its neck and head. This subspecies, like other members of ''Cyclura'', is sexually dimorphic; males are larger than females, and have more prominent dorsal crests as well as larger femoral pores on their thighs, which are used to release pheromones.

Distribution

The Acklins ground iguana is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to three small

cay A cay ( ), also spelled caye or key, is a small, low-elevation, sandy island on the surface of a coral reef. Cays occur in tropical environments throughout the Pacific, Atlantic, and Indian Oceans, including in the Caribbean and on the Great ...

s in

the Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...

. Natural populations of Acklins ground iguanas are found only on Fish Cay and North Cay in the

Acklins Acklins is an island and district of the Bahamas. It is one of a group of islands arranged along a large, shallow lagoon called the Bight of Acklins, of which the largest are Crooked Island () in the north and Acklins () in the southeast, and ...

Bight, Bahamas. They formerly inhabited Long (Fortune) Cay. An additional introduced population with five founding individuals was established on a small cay in the early 1970s. These two populations are made up of 12,500-18,800 individual animals. A translocated population in the Exumas Land and Sea Park contains 300 animals and appears to be stable.

Diet

Like all '' Cyclura'' species the Acklins ground iguana is primarily herbivorous, 95% of which from consuming

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s and

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

s from 7 different plant species such as seaside rock shrub ('' Rachicallis americana''), and erect prickly pear (''

Opuntia stricta ''Opuntia stricta'' is a species of large cactus that is endemic to the subtropical and tropical coastal areas of the Americas, especially around the Caribbean. Common names include erect prickly pear and nopal estricto (Spanish). The first desc ...

''). This diet is very rarely supplemented with animal matter, although a wild specimen has been recorded eating

mice A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

Mating

Mating occurs between May and June depending on when the dry season ends, and 2-5 eggs are usually laid within 40 days depending on the size and age of the female. Some females have been observed migrating to coastal areas on the various cays in order to build their nests in the sand, and some guard the nest site for a short period of time. The hatchlings emerge from the nests in August to early September.

Habitat

Unlike every other species of ''Cyclura'' the Acklins ground iguana is free of threats by feral predators. The cays they dwell on are remote and human populations leave the animals undisturbed. Natural predators in the form of

osprey The osprey (''Pandion haliaetus''), , also called sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor reaching more than in length and across the wings. It is brown o ...

heron The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychus ...

s, kestrels and

seagull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...

s have minimal impact on the populations. The Acklins Cays also have an abundance of food and vegetation compared to the cays on which other iguanas are found and this also must be considered as a factor in their success.

Sea level rise Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...

may be the greatest threat these animals face in the future, as the cays lack elevation relief and a sea level rise of 1 meter over the next 100 years could cost the cays up to 50% habitat loss.

References

External links

Entry at Cyclura.comBenjamin Thornton's Thesis on Acklins ground iguanas
{{Taxonbar, from=Q4674281 riley nuchalis Endemic fauna of the Bahamas Reptiles of the Bahamas Lizards of the Caribbean Endangered fauna of North America Taxonomy articles created by Polbot