Saban black iguana

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Saban black iguana
Iguana melanoderma Breuil et al 2020.jpg
In known habitat on Saba
CITES Appendix II (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Iguania
Family: Iguanidae
Genus: Iguana
Species:
Subspecies:
I. i. melanoderma
Trinomial name
Iguana iguana melanoderma
Breuil et al., 2020

The Saban black iguana (Iguana iguana melanoderma) is a subspecies (sometimes considered a distinct species) of the green iguana thought to be endemic to the islands of Saba and Montserrat, although external evidence indicates that it may be distributed in other parts of the Caribbean. It was described in 2020 as a distinct species, although the Reptile Database classifies it as a subspecies of the common green iguana (Iguana iguana). [3]

Contents

Taxonomy

The subspecies was previously considered to represent melanistic individuals of the green iguana. It was reclassified as a separate subspecies based on a number of genomic distinctions (private microsatellite alleles and unique mitochondrial ND4 haplotypes) and consistent morphological characteristics. [4] Genetic evidence indicates that I. i. melanoderma is the sister group of the green iguana populations from South America (considered I. iguana iguana), with both forming a clade that is the sister group of the green iguana populations present on St. Lucia and the Grenadines, which are considered a distinct subspecies, I. i. insularis . [4] [5] The Reptile Database also recognizes the Saban black iguana as a distinct taxonomic entity, but due to its close relation to the green iguana, it (along with the two subspecies of I. insularis) is instead classified as a subspecies of the green iguana, as I. i. melanoderma. [3]

Distribution

A member of the putative Venezuelan population, which may be the source population for the subspecies. Iguana iguana en Zoologico de Barquisimeto.jpg
A member of the putative Venezuelan population, which may be the source population for the subspecies.

As proposed in the original publication, the subspecies displays a very unusual disjunct distribution. Member populations are found on Montserrat and Saba, as well as on the Virgin Islands and the island of Vieques, and in northern Venezuela, including several coastal islets as well as the mainland vicinity of Cumaná. The mainland distribution has not been well defined. A news article indicated that it is believed the species was also present on Redonda, [5] but this was not addressed in the original publication; several authors have mentioned having seen iguanas, but no specimens have been collected, nor any fossils identified. Recent genetic insights confirm that near-indistinguishable melanistic iguanas (compared to Saba and Montserrat) have identical mitohondrial haplotypes as those two populations in the Lesser Antilles. [6] Genetic data remains to be analyzed from the populations assigned to this subspecies in Venezuela. [4]

A member of the putative Virgin Islands population, on Saint Thomas St Thomas Marriott Iguana 8.jpg
A member of the putative Virgin Islands population, on Saint Thomas

It is theorized that coastal Venezuela is the source population for I. i. melanoderma and also where it diverged from other iguanas. Three dispersal events have been proposed; one from coastal Venezuela to either Saba or Montserrat (with Montserrat being more likely if the dispersal was natural), a second pre-Columbian dispersal from one of these two islands to the other, and a third to Puerto Rico and the Virgin Islands. These dispersal events may have happened from natural dispersals, transport and introduction by Amerindians and/or European colonists, or both. As parts of its range may have been facilitated by human transport, its strange disjunct distribution may not be entirely natural in origin. [4]

A 2022 population estimate on Saba suggests that ~6000 iguanas occur on the island. [7]

Description

The Saban black iguana is darker coloured than the other subspecies of green iguana, with colouration deepening in older individuals. It possesses a black dewlap, high dorsal spikes, no horns on the snout, and carries a noticeable black patch between the eye and tympanum. [4] [7] Although the Saban black iguana has been described as more darker than other subspecies, a recent population assessment of the Saba population indicated that only a small percentage of all adults become completely melanistic. While many iguanas become only partially melanistic, all had a black facial patch between the tympanum and eye. [7]

Conservation

It has been suggested that the subspecies is threatened by unsustainable harvest for consumption and the pet trade, and by competition with and hybridization from escaped or released non-native iguana subspecies from the mainland. [4] There have been plans to reintroduce the subspecies to Redonda, where it may have formerly occurred but was extirpated from. [5]

Iguanas from Saba have been illegally exported and subsequently traded using fraudulent CITES permits, and are currently offered as pets in numerous countries across the globe. [8]

Related Research Articles

<span class="mw-page-title-main">Saba (island)</span> Dutch Caribbean island

Saba is a Caribbean island and the smallest special municipality of the Netherlands. It consists largely of the active volcano Mount Scenery, which at 887 metres (2,910 ft) is the highest point of the entire Kingdom of the Netherlands. The island lies in the northern Leeward Islands portion of the West Indies, southeast of the Virgin Islands. Together with Bonaire and Sint Eustatius it forms the BES islands, also known as the Caribbean Netherlands.

<span class="mw-page-title-main">Marine iguana</span> Species of marine reptile endemic to Galapagos Islands

The marine iguana, also known as the sea iguana, saltwater iguana, or Galápagos marine iguana, is a species of iguana found only on the Galápagos Islands (Ecuador). Unique among modern lizards, it is a marine reptile that has the ability to forage in the sea for algae, which makes up almost all of its diet. Marine iguanas are the only extant lizard that spends time in a marine environment. Large males are able to dive to find this food source, while females and smaller males feed during low tide in the intertidal zone. They mainly live in colonies on rocky shores where they bask after visiting the relatively cold water or intertidal zone, but can also be seen in marshes, mangrove swamps and beaches. Large males defend territories for a short period, but smaller males have other breeding strategies. After mating, the female digs a nest hole in the soil where she lays her eggs, leaving them to hatch on their own a few months later.

<span class="mw-page-title-main">Lesser Antillean iguana</span> Species of reptile

The Lesser Antillean iguana is a large arboreal lizard endemic to the Lesser Antilles. It is one of three species of lizard of the genus Iguana and is in severe decline due to habitat destruction, introduced feral predators, hunting, and hybridization with its introduced sister species, the green iguana. Successful captive breeding of this species has been limited to only two instances, as most captive-laid eggs tend to be infertile.

<span class="mw-page-title-main">Blue iguana</span> Species of reptile

The blue iguana, also known as the Grand Cayman ground iguana, Grand Cayman blue iguana or Cayman Island rock iguana, is an endangered species of lizard which is endemic to the island of Grand Cayman. It was previously considered to be a subspecies of the Cuban iguana, Cyclura nubila, but in a 2004 article Frederic J. Burton reclassified it as a separate species because according to him the genetic differences discovered four years earlier between the different C. nubila populations warranted this interpretation. The blue iguana is one of the longest-living species of lizard.

<span class="mw-page-title-main">Mona ground iguana</span> Species of Cyclura closely related to the rhinoceros iguana

The Mona ground iguana is a critically endangered species of rock iguana, endemic to Mona Island, Puerto Rico. It is one of the island nation's few large land animals, and it is the largest endemic terrestrial lizard in the country, and one of the biggest rock iguanas within the Antilles. It was previously considered a subspecies of the rhinoceros iguana.

<i>Ctenosaura pectinata</i> Species of lizard

Ctenosaura pectinata is a species of moderately large lizard in the family Iguanidae. The species is native to western Mexico.

<i>Cyclura rileyi</i> Species of lizard

Cyclura rileyi, commonly known as the Bahamian rock iguana or the San Salvador rock iguana, is a critically endangered species of lizard in the family Iguanidae. The species is native to three island groups in the Bahamas, and is in decline due to habitat encroachment by human development and predation by feral dogs and cats. There are three subspecies: the Acklins ground iguana, the White Cay iguana, and the nominotypical subspecies.

The Andros Island iguana or Andros iguana is an endangered subspecies of Northern Bahamian rock iguana of the genus Cyclura that is found on Andros Island on the western edge of Grand Bahama. Its status is Endangered, with a wild population of 3,500 animals, and it can be found on the IUCN Red List.

Cyclura cornuta onchiopsis, the Navassa Island iguana, was a subspecies of rhinoceros iguana that was found on the Caribbean island of Navassa.

Cyclura carinata bartschi, commonly known as Bartsch's iguana or the Booby Cay iguana, is a subspecies of lizard in the family Iguanidae. The subspecies is endemic to a single cay, Booby Cay, in The Bahamas.

<i>Cyclura nubila caymanensis</i> Subspecies of lizard

Cyclura nubila caymanensis, the Lesser Caymans iguana, Cayman Brac iguana, Cayman Island brown iguana or Sister Isles iguana, is a critically endangered subspecies of the Cuban iguana. It is native to two islands to the south of Cuba: Cayman Brac and Little Cayman, which are also known as the Sister Isles due to their similar shapes and close proximity to each other. The population of this subspecies has been impacted by habitat encroachment by human development and is likely being destroyed due to predation by cats, the population on Cayman Brac has remained particularly small for decades.

<i>Ctenosaura similis</i> Black iguana, native to central America

Ctenosaura similis, commonly known as the black iguana or black spiny-tailed iguana, is a lizard native to Mexico and Central America. It has been reported in some Colombian islands in the Caribbean Sea and Pacific Ocean, and has been introduced to the United States in the state of Florida. It is the largest species in the genus Ctenosaura. They are typically found in areas such as grasslands and forests.

<i>Iguana</i> Reptile genus of herbivorous lizards

Iguana is a genus of herbivorous lizards that are native to tropical areas of Mexico, Central America, South 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. Three species are placed in the genus: the green iguana, which is widespread throughout its range and a popular pet, the marine iguana and the Lesser Antillean iguana, which is native to the Lesser Antilles. Genetic analysis indicates that the green iguana may comprise a complex of multiple species, some of which have been recently described, but the Reptile Database considers all of these as subspecies of the green iguana.

The Sombrero ameiva is a lizard species in the genus Ameiva. It is endemic to Sombrero, a small, uninhabited island in the Lesser Antilles under the jurisdiction of Anguilla.

The Montserrat ameiva is a lizard species in the genus Pholidoscelis. It is found on the Caribbean island of Montserrat in the Lesser Antilles.

<i>Gymnophthalmus underwoodi</i> Species of lizard

Gymnophthalmus underwoodi, called commonly Underwood's spectacled tegu, is a species of microteiid lizard, which is found in South America and on certain Caribbean islands.

<i>Anolis sabanus</i> Species of lizard

Anolis sabanus, the Saba anole or Saban anole, is a species of anole lizard that is endemic to the island of Saba, a Dutch municipality in the Caribbean Lesser Antilles.

The green thornytail iguana is an arboreal species of lizard from the Amazon rainforest and forests in the Guiana Shield. It is found in Colombia, Guyana, Suriname, French Guiana, northeastern Peru, southern Venezuela, and northern Brazil. As in U. flaviceps, U. azureum primarily feeds on ants.

<span class="mw-page-title-main">Green iguana</span> Species of reptile

The green iguana, also known as the American iguana or the common green iguana, is a large, arboreal, mostly herbivorous species of lizard of the genus Iguana. Usually, this animal is simply called the iguana. The green iguana ranges over a large geographic area; it is native from southern Brazil and Paraguay as far north as Mexico.

References

  1. van den Burg, M.P.; Debrot, A.O. (2022). "Iguana iguana (Saba subpopulation)". IUCN Red List of Threatened Species . 2022: e.T220903552A220903555. Retrieved 27 July 2022.
  2. "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. 1 2 "Iguana iguana". The Reptile Database. Retrieved 2021-04-26.
  4. 1 2 3 4 5 6 Breuil, M.; Schikorski, D.; Vuillaume, B.; Krauss, U.; Morton, M.N.; Corry, E.; Bech, N.; Jelić, M.; Grandjean, F. (2020). "Painted black: Iguana melanoderma (Reptilia, Squamata, Iguanidae) a new melanistic endemic species from Saba and Montserrat islands (Lesser Antilles)". ZooKeys (926): 95–131. doi: 10.3897/zookeys.926.48679 . PMC   7170970 . PMID   32336922.
  5. 1 2 3 Knight, Tim; Fauna; International, Flora (2020-06-10). "A Tale of Two Iguanas: New Species Found Hiding in Plain Sight". SciTechDaily. Retrieved 2020-08-03.
  6. De Jesús Villanueva, Christina N.; Falcón, Wilfredo; Velez-Zuazo, Ximena; Papa, Riccardo; Malone, Catherine Lyn (17 April 2021). "Origin of the green iguana (Iguana iguana) invasion in the greater Caribbean Region and Fiji". Biological Invasions. 23 (8): 2591–2610. doi:10.1007/s10530-021-02524-5. eISSN   1573-1464. ISSN   1387-3547. S2CID   234837961.
  7. 1 2 3 van den Burg, Matthijs P.; Madden, Hannah; Debrot, Adolphe O. (20 May 2022), Population estimate, natural history and conservation of the melanistic ''Iguana Iguana'' population on Saba, Caribbean Netherlands, Cold Spring Harbor Laboratory, doi:10.1101/2022.05.19.492665, S2CID   248990505
  8. van den Burg, Matthijs P.; Weissgold, Bruce J. (October 2020). "Illegal trade of morphologically distinct populations prior to taxonomic assessment and elevation, with recommendations for future prevention". Journal for Nature Conservation. 57: 125887. doi:10.1016/j.jnc.2020.125887. ISSN   1617-1381. S2CID   224995636.