Cyclura rileyi
Encyclopedia
Cyclura rileyi, commonly known as the San Salvador Rock Iguana or Bahamian Rock Iguana, is a critically endangered species of lizard
of the genus Cyclura
native to three island groups in the Bahamas
. The species is in decline due to habitat encroachment by human development and predation by feral dog
s and cat
s. Taxonomically there are two subspecies
: the Acklins Ground Iguana
(Cyclura rileyi nuchalis), the White Cay Iguana
(Cyclura rileyi cristata) in addition to the nominal species.
of the genus Cyclura
from the family Iguanidae
. First identified by Leonhard Hess Stejneger
in 1902, they are known commonly in the Bahamas as iguanas. Its generic
name Cyclura
, is derived from the Greek
words cyclos meaning "circular" and urus meaning "tail", after the thick ringed tail characteristic of all Cyclura iguana
s. Its specific name, rileyi, is a Latinized form of the name of American biologist
, Joseph Harvey Riley
.
As of 1975 two additional subspecific forms have been identified along with the nominal subspecies: the Acklins Ground Iguana
(C. r. nuchalis) and the White Cay Iguana
(C. r. cristata). Together they are one of the most threatened species of all the West Indian rock iguanas
and are described as critically endangered according to the current IUCN Red List.
Males of this subspecies, like other species within the Genus Cyclura, are larger than females, and have more prominent dorsal
crests in addition to prominent femoral pore
s on their thighs, which are used to release pheromones. Females have less prominent pores and have shorter crests than the males making the animals sexually dimorphic
.
, today they are confined to 6 populations in small remote cay
s of three island groups: San Salvador Island
, Acklins
, and Exuma
.A study in 1995 estimated there were between 426 and 639 specimens left in the wild, and that this number has likely been reduced since much of their habitat was destroyed in 1999 by Hurricane Floyd
. The three island groups, each harboring its own subspecies, are on separate banks and were not connected during the last glacial period when water levels were 100 m (328.1 ft) lower than they are at present.
species the San Salvador Rock Iguana is primarily herbivorous
, 95% of which from consuming leaves
, flower
s and fruit
s from 7 different plant species such as Seaside Rock Shrub (Rachicallis americana), and Erect Prickly Pear (Opuntia stricta
). This diet is very rarely supplemented with insect
larva
e, crab
s, slug
s, dead
bird
s and fungi
.
Mating occurs in May and June, with clutches of 3-10 eggs usually laid in June or July, in nests excavated in pockets of earth exposed to the sun. Individuals are aggressively territorial from the age of about 3 months.
s as well as the introduction of non-native species. Imported black rat
s, raccoons
, feral dog
s, mongoose
, hogs, and cat
s have taken their toll on the population by direct predation, as has the larvae of a moth (Cactoblastis cactorum
), introduced decades ago to the Caribbean
, which are rapidly devastating prickly-pear cacti
, an important food source for the iguanas. The Guana Cay population has been reduced to less than 24 individual animals.
Other threats by humans include tourists trampling iguanas' nests, iguanas contracting disease from eating human garbage, and illicit smuggling
for the pet trade. As development increases on the islands and further isolates populations, these animals will be threatened by lack of gene flow between the cays.
As of August 2007, no legal captive breeding programs exist outside of the Bahamas. The Bahamian government has refused to issue export permits for any rock iguanas. However, Ardastra Gardens in Nassau
(New Providence Island, Bahamas) currently holds two juveniles and plans to implement a captive breeding program. A public relations campaign is planned to heighten awareness and appreciation among island residents for this endemic lizard.
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
of the genus Cyclura
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
native to three island groups in the Bahamas
The Bahamas
The Bahamas , officially the Commonwealth of the Bahamas, is a nation consisting of 29 islands, 661 cays, and 2,387 islets . It is located in the Atlantic Ocean north of Cuba and Hispaniola , northwest of the Turks and Caicos Islands, and southeast of the United States...
. The species is in decline due to habitat encroachment by human development and predation by feral dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s and cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s. Taxonomically there are two subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
: the Acklins Ground Iguana
Acklins Ground Iguana
Cyclura rileyi nuchalis, commonly known as the Acklins Ground Iguana or Watling Island Iguana, is an endangered subspecies of lizard of the genus Cyclura it is one of three subspecific forms of Cyclura rileyi in the Iguanidae family....
(Cyclura rileyi nuchalis), the White Cay Iguana
Cyclura rileyi cristata
Cyclura rileyi cristata, commonly known as the White Cay Iguana or Sandy Cay Rock Iguana, is a critically endangered subspecies of lizard of the genus Cyclura native to a single cay in the Bahamas: White Cay located in the Southern Exumas.-Taxonomy:The White Cay iguana is an endangered subspecies...
(Cyclura rileyi cristata) in addition to the nominal species.
Taxonomy
The San Salvador Rock Iguana is an endangered species of lizardLizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
of the genus Cyclura
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
from the family Iguanidae
Iguanidae
Iguanidae is a family of lizards, composed of iguanas and related species.-Classification of Iguanidae:Two different classification schemes have been used to define the structure of this family. These are the "traditional" classification and the classification presented by Frost et al. .Frost et...
. First identified by Leonhard Hess Stejneger
Leonhard Hess Stejneger
Leonhard Hess Stejneger was a Norwegian-born American ornithologist, herpetologist and zoologist. Stejneger specialized in vertebrate natural history studies. He gained his greatest reputation with reptiles and amphibians....
in 1902, they are known commonly in the Bahamas as iguanas. Its generic
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
name Cyclura
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
, is derived from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
words cyclos meaning "circular" and urus meaning "tail", after the thick ringed tail characteristic of all Cyclura iguana
Iguana
Iguana is a herbivorous genus of lizard native to tropical areas of Central America and the Caribbean. The genus was first described in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his book Specimen Medicum, Exhibens Synopsin Reptilium Emendatam cum Experimentis circa Venena...
s. Its specific name, rileyi, is a Latinized form of the name of American biologist
Biologist
A biologist is a scientist devoted to and producing results in biology through the study of life. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work...
, Joseph Harvey Riley
Joseph Harvey Riley
Joseph Harvey Riley 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 Birds in 1932.-Sources:*...
.
As of 1975 two additional subspecific forms have been identified along with the nominal subspecies: the Acklins Ground Iguana
Acklins Ground Iguana
Cyclura rileyi nuchalis, commonly known as the Acklins Ground Iguana or Watling Island Iguana, is an endangered subspecies of lizard of the genus Cyclura it is one of three subspecific forms of Cyclura rileyi in the Iguanidae family....
(C. r. nuchalis) and the White Cay Iguana
Cyclura rileyi cristata
Cyclura rileyi cristata, commonly known as the White Cay Iguana or Sandy Cay Rock Iguana, is a critically endangered subspecies of lizard of the genus Cyclura native to a single cay in the Bahamas: White Cay located in the Southern Exumas.-Taxonomy:The White Cay iguana is an endangered subspecies...
(C. r. cristata). Together they are one of the most threatened species of all the West Indian rock iguanas
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
and are described as critically endangered according to the current IUCN Red List.
Anatomy and morphology
Measuring 300 to 390 mm (11.8 to 15.4 in) in length when full grown, the San Salvador Rock Iguana is a colorful lizard varying between subspecies as well as between individual specimens. 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, blue, 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.Males of this subspecies, like other species within the Genus Cyclura, are larger than females, and have more prominent dorsal
Dorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
crests in addition to prominent femoral pore
Femoral pore
Femoral pores are a part of a holocrine secretory gland found on the inside of the thighs of certain lizards and amphisbaenians which releases pheromones to attract mates or mark territory. In certain species only the male has these pores and in other species, both sexes have them, with the males...
s on their thighs, which are used to release pheromones. Females have less prominent pores and have shorter crests than the males making the animals sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
.
Distribution
Once inhabiting all the large islands of the BahamasThe Bahamas
The Bahamas , officially the Commonwealth of the Bahamas, is a nation consisting of 29 islands, 661 cays, and 2,387 islets . It is located in the Atlantic Ocean north of Cuba and Hispaniola , northwest of the Turks and Caicos Islands, and southeast of the United States...
, today they are confined to 6 populations in small remote cay
Cay
A cay , also spelled caye or key, is a small, low-elevation, sandy island formed on the surface of coral reefs. Cays occur in tropical environments throughout the Pacific, Atlantic and Indian Oceans , where they provide habitable and agricultural land for hundreds of thousands of people...
s of three island groups: San Salvador Island
San Salvador Island
San Salvador Island, also known as Watlings Island, is an island and district of the Bahamas. Until 1986, when the National Geographic Society suggested Samana Cay, it was widely believed that during his first expedition to the New World, San Salvador Island was the first land sighted and visited...
, Acklins
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 the smaller are Long Cay [ 8sq mi] in the northwest, and...
, and Exuma
Exuma
Exuma is a district of the Bahamas, consisting of over 360 islands . The largest of the cays is Great Exuma, which is 37 mi in length and joined to another island, Little Exuma by a small bridge. The capital and largest city in the district is George Town , founded 1793 and located on Great...
.A study in 1995 estimated there were between 426 and 639 specimens left in the wild, and that this number has likely been reduced since much of their habitat was destroyed in 1999 by Hurricane Floyd
Hurricane Floyd
Hurricane Floyd was the sixth named storm, fourth hurricane, and third major hurricane in the 1999 Atlantic hurricane season. Floyd triggered the third largest evacuation in US history when 2.6 million coastal residents of five states were ordered from their homes as it approached...
. The three island groups, each harboring its own subspecies, are on separate banks and were not connected during the last glacial period when water levels were 100 m (328.1 ft) lower than they are at present.
Diet
Like all CycluraCyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
species the San Salvador Rock Iguana is primarily herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
, 95% of which from consuming leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
, flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s and fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s from 7 different plant species such as Seaside Rock Shrub (Rachicallis americana), and Erect Prickly Pear (Opuntia stricta
Opuntia stricta
Opuntia stricta is a species of cactus from southern North America, Central America, the Caribbean, and northern South America. Common names include Erect Prickly Pear and Nopal Estricto ....
). This diet is very rarely supplemented with insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...
s, dead
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s and fungi
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
.
Mating
Female San Salvador rock iguanas attain sexual maturity when they reach 20 cm (7.9 in) in length from snout to vent and weigh 300 g (10.6 oz). Males appear to mature at a slightly larger size, at approximately seven years of age.Mating occurs in May and June, with clutches of 3-10 eggs usually laid in June or July, in nests excavated in pockets of earth exposed to the sun. Individuals are aggressively territorial from the age of about 3 months.
Conservation
While the island's natives often used iguanas as food and funerary offerings in pre-colonial times, man's largest-scale devastation to these animals was as a result of clear-cutting forests to create plantationPlantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
s as well as the introduction of non-native species. Imported black rat
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
s, raccoons
Bahaman Raccoon
- Bahamian Raccoon :The Bahamian raccoon , also called Bahama raccoon or Bahamas raccoon, is a subspecies of the common raccoon endemic on the New Providence Island in the Bahamas.- Classification :...
, feral dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s, mongoose
Mongoose
Mongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...
, hogs, and cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s have taken their toll on the population by direct predation, as has the larvae of a moth (Cactoblastis cactorum
Cactoblastis cactorum
Cactoblastis cactorum, commonly known as the Cactus Moth, South American Cactus Moth, or Nopal Moth, is native to Argentina, Paraguay, Uruguay, and southern Brazil. It is one of five species in the genus Cactoblastis that lives in South America...
), introduced decades ago to the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
, which are rapidly devastating prickly-pear cacti
Opuntia
Opuntia, also known as nopales or paddle cactus , is a genus in the cactus family, Cactaceae.Currently, only prickly pears are included in this genus of about 200 species distributed throughout most of the Americas. Chollas are now separated into the genus Cylindropuntia, which some still consider...
, an important food source for the iguanas. The Guana Cay population has been reduced to less than 24 individual animals.
Other threats by humans include tourists trampling iguanas' nests, iguanas contracting disease from eating human garbage, and illicit smuggling
Smuggling
Smuggling is the clandestine transportation of goods or persons, such as out of a building, into a prison, or across an international border, in violation of applicable laws or other regulations.There are various motivations to smuggle...
for the pet trade. As development increases on the islands and further isolates populations, these animals will be threatened by lack of gene flow between the cays.
As of August 2007, no legal captive breeding programs exist outside of the Bahamas. The Bahamian government has refused to issue export permits for any rock iguanas. However, Ardastra Gardens in Nassau
Nassau, Bahamas
Nassau is the capital, largest city, and commercial centre of the Commonwealth of the Bahamas. The city has a population of 248,948 , 70 percent of the entire population of The Bahamas...
(New Providence Island, Bahamas) currently holds two juveniles and plans to implement a captive breeding program. A public relations campaign is planned to heighten awareness and appreciation among island residents for this endemic lizard.