Cyclura

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Cyclura
Cyclura cornuta.JPG
Cyclura cornuta, rhinoceros iguana
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Iguania
Family: Iguanidae
Genus: Cyclura
Harlan, 1825

Cyclura is a genus of lizards in the family Iguanidae. Member species of this genus are commonly known as "cycluras" or more commonly as rock iguanas and only occur on islands in the West Indies.[1] Rock iguanas have a high degree of endemism, with in most cases a single species or subspecies restricted to an individual island.[2][3]

Taxonomy[edit]

The genus Cyclura was first circumscribed by Richard Harlan in 1825 to include two new species of lizard: C. carinata and C. teres. C. teres eventually turned out to be a junior synonym of Ctenosaura acanthura.[4]

Currently, there are nine described species and eight subspecies identified in this genus.[2][5][6][7][8]

One author considers the Mona ground iguana to be an independent species,[9] although this has not been accepted by other workers.

Habitat[edit]

Rock iguanas most often inhabit subtropical areas of West Indian dry forest biomes characterized by eroded limestone and sparse vegetation ranging from only moderately dry acacia forest to much drier mesquite and cactus habitats. These are islands made up of heavily eroded limestone which form natural caves.[12]

Diet and longevity[edit]

Acklin's Island iguana basking on a rock

All rock iguanas are herbivorous, consuming leaves, flowers, berries, and fruits from different plant species. Their diet is very rarely supplemented with insect larvae, crabs, slugs, dead birds, and fungi; individual animals do appear to be opportunistic carnivores.[3][13]

A study in 2000 by Allison Alberts revealed that seeds passing through the digestive tracts of C. nubila nubila rock iguanas germinate more rapidly than those that do not. These seeds in the fruits consumed by this species have an adaptive advantage by sprouting before the end of very short rainy seasons. She theorised these iguanas may be an important means of distributing such seeds to new areas.[14]

The record for the longest lived captive-born rock iguana is held by a Lesser Caymans iguana, which lived for 33 years in captivity.[15]

A blue iguana captured on Grand Cayman in 1950 by naturalist Ira Thompson was imported to the United States in 1985 by Ramon Noegel and sold to reptile importer and breeder, Tom Crutchfield. Crutchfield loaned this iguana to the Gladys Porter Zoo in Brownsville, Texas in 1997. The lizard was named Godzilla by the zoo staff and was kept until his death in 2004. Thompson estimated the iguana to be 15 years of age at the time of its capture. This lizard may have been the word's longest-living recorded lizard at 69 years of age, having spent 54 years in captivity.[16]

Reproduction[edit]

All species of Cyclura are 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.[17][18]

The particulars vary slightly among species and subspecies, the rock iguanas reach sexual maturity at three to seven years of age. Females become sexually mature at two to five years of age. Males can be highly territorial with the notable exception of the Exuma Island iguana. Mating takes place at the beginning of or just prior to the first rainy season of the year (May to June) and lasts for two to three weeks. Females lay from 2 to 34 eggs, with an average clutch size of 17 within 40 days. Females of most species guard their nests for several days after laying their eggs, and incubation lasts approximately 85 days. It has been noted that Cyclura eggs are among the largest lizard eggs produced in the world.[17]

Conservation[edit]

In 1996 nine of these taxa were assessed as critically endangered, four taxa are endangered and three species have been identified as vulnerable; one species is believed to be extinct. In addition to small numbers typical of endemic island-dwelling animals, wild populations of these lizards are directly and indirectly impacted by land development, overgrazing by domestic and feral livestock and predation by introduced mammals such as hogs, cats, rats, dogs, and mongooses.[2]

In 1990, the American Zoo and Aquarium Association (AZA) designated the genus Cyclura as their highest priority. Their first project was a captive breeding program for the Grand Cayman iguana, which at the time was the most critically endangered of all the species of Cyclura.[19]

The Indianapolis Zoo was involved in research and conservation of all sixteen taxa of West Indian iguanas. This includes collaborative work on establishing baseline biological information in captive and wild iguanas, scientific investigation, conservation efforts, field research and captive breeding programs.[19]

Grand Cayman blue iguana, Cyclura lewisi

References[edit]

  1. ^ Dayhuff, Becky (2006-02-01), "Rock Iguanas of the Caribbean", All at Sea Magazine[permanent dead link]
  2. ^ a b c Malone, Catherine; Davis, Scott (2004), "Genetic Contributions to Caribbean Iguana Conservation", Iguanas: Biology and Conservation, University of California Press, pp. 45–57, ISBN 978-0-520-23854-1
  3. ^ a b Blair, David (1991), "WEST INDIAN IGUANAS OF THE GENUS Cyclura Their Current Status in the Wild, Conservation Priorities and Efforts to Breed Them in Captivity" (PDF), Northern California Herpetological Society Special Publication, SE (6), pp. 55–56, archived from the original (PDF) on 2008-04-11
  4. ^ Harlan, Richard (1825). "Description of two Species of Linnæan Lacerta, not before described, and construction of the new genus Cyclura". Journal of the Academy of Natural Sciences of Philadelphia (Series 1). 4 (2): 242–251. Retrieved 22 February 2020.
  5. ^ "Cyclura: Harlan, 1825", Integrated Taxonomic Information System, 2001, retrieved 2007-10-07
  6. ^ Schwartz, A.; Carey, M. (1977), "Systematics and evolution in the West Indian iguanid genus Cyclura", Studies on the Fauna of Curaçao and Other Caribbean Islands, 173, pp. 15–97
  7. ^ Frost, D.E. and R.E. Etheridge (1989) A Phylogenetic Analysis and Taxonomy of Iguanian Lizards (Reptilia: Squamata). Univ. Kansas Mus. Nat. Hist. Misc. Publ. 81
  8. ^ Frost, D.R., R. Etheridge, D. Janies and T.A. Titus (2001) Total evidence, sequence alignment, evolution of Polychrotid lizards, and a reclassification of the Iguania (Squamata: Iguania) American Museum Novitates 3343: 38 pp.
  9. ^ a b c d e f g h i j k l m n o p Hollingsworth, Bradford D. (2004), "The Evolution of Iguanas: An Overview of Relationships and a Checklist of Species", Iguanas: Biology and Conservation, University of California Press, pp. 35–39, ISBN 978-0-520-23854-1
  10. ^ Cyclura cychlura, The Reptile Database
  11. ^ Burton, Frederic (2004), "Taxonomic Status of the Grand Cayman Blue Iguana" (PDF), Caribbean Journal of Science, 8 (1), pp. 198–203, retrieved 2007-09-16
  12. ^ Knapp, Charles R.; Hudson, Richard D. (2004), "Translocation Strategies as a Conservation Tool for West Indian Iguanas", Iguanas: Biology and Conservation, University of California Press, pp. 199–209, ISBN 978-0-520-23854-1
  13. ^ Alberts, Allison (9 December 2004). The Grand Cayman Blue Iguana – Species Recovery Plan 2001–2006 (PDF). Grand Cayman: Blue Iguana Recovery Program. p. 29. Retrieved 2007-09-08.
  14. ^ Alberts, Allison; Lemm, Jeffrey; Grant, Tandora; Jackintell, Lori (2004), "Testing the Utility of Headstarting as a Conservation Strategy for West Indian Iguanas", Iguanas: Biology and Conservation, University of California Press, p. 210, ISBN 978-0-520-23854-1
  15. ^ Iverson, John; Smith, Geoffrey; Pieper, Lynne (2004), "Factors Affecting Long-Term Growth of the Allen Cays Rock Iguana in the Bahamas", Iguanas: Biology and Conservation, University of California Press, p. 184, ISBN 978-0-520-23854-1
  16. ^ Adams, Colette (May 26, 2004), "Obituary" (PDF), Iguana Specialist Group Newsletter, 7 (1): 2, archived from the original (PDF) on August 12, 2007, retrieved October 5, 2007
  17. ^ a b De Vosjoli, Phillipe; David Blair (1992), The Green Iguana Manual, Escondido, California: Advanced Vivarium Systems, ISBN 1-882770-18-8
  18. ^ Martins, Emilia P.; Lacy, Kathryn (2004), "Behavior and Ecology of Rock Iguanas,I: Evidence for an Appeasement Display", Iguanas: Biology and Conservation, University of California Press, pp. 98–108, ISBN 978-0-520-23854-1
  19. ^ a b Hudson, Richard D.; Alberts, Allison C. (2004), "The Role of Zoos in the Conservation of West Indian Iguanas", Iguanas: Biology and Conservation, University of California Press, pp. 274–289, ISBN 978-0-520-23854-1

External links[edit]