View source for El Hierro giant lizard

{{Short description|Subspecies of lizard}}
{{subspeciesbox
| fossil_range = {{Fossil range|0.01|0}} [[Late Pleistocene]]–Recent
| name = El Hierro giant lizard
| image = Lagarto Gigante de El Hierro, Canarias, España.JPG
| status = CR
| status_system = IUCN3.1
| status_ref = <ref name=IUCN>{{cite iucn |author=Jose Antonio Mateo Miras, Valentin Pérez-Mellado, Iñigo Martínez-Solano |date=2009 |title=''Gallotia simonyi'' |volume=2009 |page=e.T8881A12935900 |doi=10.2305/IUCN.UK.2009.RLTS.T8881A12935900.en |access-date=18 November 2021}}</ref>
| status2 = E
| status2_system = ESA
| status2_ref = <ref name = "Miras">{{Cite web |url=https://ecos.fws.gov/ecp0/profile/speciesProfile?sId=6203 |title=Species Profile for Hierro Giant lizard (Gallotia simonyi simonyi) |access-date=2020-01-30 |archive-date=2017-10-18 |archive-url=https://web.archive.org/web/20171018171241/https://ecos.fws.gov/ecp0/profile/speciesProfile?sId=6203 |url-status=dead }}</ref>
| genus = Gallotia
| species = simonyi
| subspecies = machadoi
| authority = Lopez-Jurado, 1989
| range_map = Gallotia simonyi range Map.png
| range_map_caption = Range in the Canary Islands
}}
The '''El Hierro giant lizard''' (''Gallotia simonyi machadoi'') is the only extant, [[critically endangered]] [[subspecies]] of [[Gallotia simonyi|Simony's giant lizard]]. It is [[endemic species|endemic]] to [[El Hierro]], the westernmost of the [[Canary Islands]], where it is an [[List of animal and plant symbols of the Canary Islands|official symbol]].<ref>{{cite act |type=Ley |index=7/1991 |date=30 April 1991 |title=Símbolos de la naturaleza para las Islas Canarias |trans-title=Natural Symbols for the Canary Islands |url=https://www.boe.es/buscar/act.php?id=BOE-A-1991-16276 |language=es |via=[[Boletín Oficial del Estado|BOE]] |volume=151 |pages=20946–20497}}</ref>

==Description==
[[File:Gallotia simonyi-female.norarte.jpg|200px|thumb|left|Female.]]
In 1999, wild adult males from Tibataje were measured between 120 and 200 [[Millimetre|mm]] in length, excluding the tail, and females between 110 and 160&nbsp;mm. An earlier study in 1985 using fewer animals measured females up to 174&nbsp;mm. The size is smaller than the observed in the [[extinction|extinct]] nominate subspecies from Roque Chico de Salmor, ''[[Roque Chico de Salmor giant lizard|G. s. simonyi]]'' (223–236&nbsp;mm in males and 174–197 in females). However, individuals raised in captivity from Tibataje stock reach larger sizes, 144–226&nbsp;mm for the males and 143–204&nbsp;mm for the females. Tail is roughly 1'4-1'7 times as long as the rest of the body in both sexes.<ref name = "Salvador"/> [[Subfossil]] remains evidence that El Hierro giant lizards were much larger before the [[Guanches]] colonized the island at the end of the [[first millennium BC]], with some individuals estimated to have surpassed one [[meter]] in total length.<ref name = "Mateo"/>

Besides being smaller and less robust, the subspecies differs from the nominate in having the top of the head less triangular and more oval, less depressed head, and on average, fewer dorsal scales, more temporal scales, fewer femoral pores, and fewer scales on the sixth ring of the tail.<ref name = "Salvador"/>

==Distribution and habitat==
[[File:Tabaibal_cardonal_malpais_Güímar.jpg|180px|thumb|left|"''[[:es:cardonal-tabaibal|Cardonal-tabaibal]]''" vegetation of the Canary Islands, dominated by species of the genus ''Euphorbia''.]]
Subfossil remains reveal that the El Hierro giant lizard was once widespread through the island,<ref name = "Mateo"/> up to 700 meters above sea level.<ref name = "Salvador"/> The potential vegetation of these areas includes ''[[Euphorbia]]'', thermophile forest, and [[Canarian pine]], though the lizards generally stayed away from forested areas.<ref name = "Mateo"/><ref name = "Miteco"/>

The subspecies later became restricted to the southern end of the Tibataje crag in {{ill|Fuga de Gorreta|es}}, between Guinea and Paso del Pino, occupying an area of about four [[hectare]]s. This is a steep cliff area, 1100 meters tall, that offers protection from invasive mammals. This population is stabilized at 250 animals.<ref name = "Miteco">[https://www.miteco.gob.es/es/biodiversidad/temas/inventarios-nacionales/reptil_27_tcm30-98932.pdf Ministerio para la Transición Ecológica y el Reto Demográfico]</ref> The area is occupied by [[deserts and xeric shrublands|xeric]] [[scrubland]] dominated by ''[[Euphorbia brousssonetii]]'' on the higher parts, ''[[Senecio kleinia]]'' and ''[[Periploca laevigata]]'' below. Other vegetation includes ''[[Kleinia neriifolia]]'', ''[[Echium|Echium hierrense]]'', ''[[Lavandula canariensis]]'', ''[[Artemisia thuscula]]'', ''[[Psoralea bituminosa]]'', ''[[Micromeria|Micromeria hyssopifolia]]'' and ''[[Cistus monspeliensis]]''.<ref name = "Salvador"/>

A second population was established in 1999 by releasing 36 captive-bred animals on Roque Chico de Salmor,<ref name = "Salvador">Salvador, A. (2015) [https://digital.csic.es/bitstream/10261/109278/3/galsim_v4.pdf Lagarto gigante de El Hierro – Gallotia simonyi]. In: ''Enciclopedia Virtual de los Vertebrados Españoles.'' Salvador, A., Marco, A. (Eds.). Museo Nacional de Ciencias Naturales, Madrid. http://www.vertebradosibericos.org/</ref> a small islet northwest of El Hierro that was inhabited by the nominate subspecies ''G. s. simonyi'' until 1931.<ref name = "Mateo">Mateo, J. A., Barone, R., Hernández-Acosta, C. N., & López-Jurado, L. F. (2020) La muerte anunciada de dos gigantes macaronésicos: el gran escinco caboverdiano, Chioninia coctei (Duméril & Bibron, 1839) y el lagarto de Salmor, Gallotia simonyi (Steindachner, 1889). ''Bol. Asoc. Herpetol. Esp.'' Vol. 31 (2), pgs. 3-30.</ref> The islet is home to breeding [[seabird]]s but has sparse vegetation<ref name = "Mateo"/> consisting of ''[[Astydamia|Astydamia latifoliae]]'', ''[[Mesembrianthemum]]'', ''[[Chenopodium]]'', ''[[Chenoloides|Chenoloides tomentosa]]'', ''[[Beta (genus)|Beta]]'', ''[[Silene (genus)|Silene]]'' and ''[[Rubia|Rubia fruticosa]]''. The population later multiplied to 120 animals.<ref name = "Salvador"/>

==Ecology and behavior==
===Diet===
El Hierro giant lizards are omnivorous. They consume mainly plants but also [[coleoptera]]ns, [[ant]]s, and small [[vertebrate]]s including [[house mouse]], [[Boettger's lizard]], [[Boettger's wall gecko]], and [[bird]]s. They distinguish and recognize the smell of plants and animals they eat. Consumed plants include [[Liliaceae]], ''Psoralea bituminosa'', [[Graminaceae]], ''Lavandula canariensis'', ''Euphorbia broussonetti'', ''Rubia fruticosa'', ''[[Schyzogone sericea]]'', ''Echium hierrense'', ''[[Euphorbia obtusolia]]'', fruit of ''[[Rumex lunaria]]'', other [[flower]]s and [[seed]]s. In Roque Chico de Salmor, lizards have been observed eating dead [[orthoptera]]ns that were regurgitated by chicks of [[yellow-legged gull]]s.<ref name = "Salvador"/>

===Reproduction===
[[File:Gallotia_simonyi-juvenile.norarte.jpg|200px|thumb|Juvenile.]]
In the first two weeks of May, the ocelli on the sides of the male turn bright yellow and both sexes become more aggressive. Before mating, the male inflates its throat and moves its head up and down, advances in a curve and bites the female on the nape. The female responds to the male's advances with quick head movements and shaking the proximal end of the tail up and down. Females can retain viable [[sperm]] in their bodies for a year. A clutch of eggs is laid between 6 June and 3 August; sometimes a second clutch is laid between 16 and 23 August. The number of eggs varies between five and thirteen; the older the female, the more eggs are laid. Eggs incubate at 28-29&nbsp;°C for 61 days. Newborns weight 3-6 [[gram]]s and measure 44–58&nbsp;mm, plus a tail of 87–133&nbsp;mm. Females mature after a minimum of four years and are always more numerous than the males.<ref name = "Salvador"/>

===Predation===
[[Common kestrel]]s, [[common buzzard|buzzards]], and [[common raven|ravens]] are believed to be the natural predators of the El Hierro giant lizard, at least as a juvenile. Predation of adults and juveniles by introduced [[feral cat]]s and [[brown rat]]s is well attested, being the main threat to the species's survival.<ref name = "Salvador"/> Before protection, adult lizards were also killed by [[herding dog]]s when they ventured into the lower areas of Tibataje.<ref name = "Böhme"/> In the event of predation, the El Hierro giant lizard's main defence is to run away, though it is slower than other ''[[Gallotia]]'' species. Juveniles suffer more predation than adults. Sometimes adults choose to face a potential predator opening their mouth and making noise, but this behavior is less common than in the [[Gran Canaria giant lizard]], ''G. stehlini''.<ref name = "Salvador"/>

Known [[parasite]]s include [[nematode]]s (''[[Thelandros filiformis]]'', ''[[Thelandros galloti|T. galloti]]'', ''[[Parapharyngodon micipsae]]''), [[protozoan]]s (''[[Sarcocystis simonyi]]''), [[bacteria]] (''[[Staphylococcus saprophyticus]]'', ''[[Staphylococcus viridans|S. viridans]]'', ''[[Citrobacter braaki]]'', ''[[Citrobacter diversus|C. diversus]]'', ''[[Salmonella enterica]]''), and [[fungi]] (''[[Aspergillus terreus]]'', ''[[Rhodoturula glutinis]]'').<ref name = "Salvador"/>

===Other relations and adaptations===
El Hierro giant lizards frequent an area of 200 to 300 m<sup>2</sup> but are not territorial. Adults tolerate the presence of other animals and even climb on top of one another. Juveniles display hostility to animals of the same age, but ignore Boettger's lizards of the same size.<ref name = "Salvador"/>

The species is diurnal, remaining  active for most of the day and the whole year, in the wet and dry season alike, with just a slight descent of activity or increased hiding in the summer. The preferred temperature is 35.6&nbsp;°C for adults and 36.3&nbsp;°C for juveniles. However they tolerate and remain active at lower temperatures than other ''Gallotia'' species.<ref name = "Salvador"/>

==History==
===Decline===
[[Mitochondrial DNA]] studies indicate that the two subspecies separated recently, as a result of rising sea levels at the end of the [[Pleistocene]].<ref name = "Salvador"/> The first human inhabitants of the island ate lizards, introduced [[dog]]s and possibly [[cat]]s that also predated on them. As a result, the lizards decreased in size and disappeared from some regions. Nevertheless, they were still common enough upon European arrival for both [[Jean de Bethencourt]] and [[Gadifer de La Salle]] to mention them in their writings, in which they describe lizards as big as cats.<ref name = "Mateo"/> The clearing of the thermophile forest, definitive introduction of predating cats and also [[rat]]s, and competing [[goat]]s and [[rabbit]]s,<ref name = "Salvador"/> put the El Hierro giant lizards into decline from the 15th century.<ref name = "Miteco"/> By the 17th century they could only be found in three or four places in the island, after which they disappear from writing accounts. The species was forgotten by the end of the 18th century, when [[José de Viera y Clavijo]] speculated that rumors about giant lizards existing in an islet off the coast of the island might refer to [[caiman]]s. However, others like 19th century notary Antonio María Manrique y Saavedra thought they were large lizards like those found in other Canary Islands.<ref name = "Mateo"/>

The species ''G. simonyi'' was discovered for science in 1889, when Oskar Simony found the lizards of Roque Chico de Salmor while investigating Viera y Clavijo's account at the request of [[Franz Steindachner]] of the [[Naturhistorisches Museum]] in [[Vienna]]. The islet instantly became a magnet for European naturalists, adventurers, collectors, and [[wildlife trade|wildlife traffickers]] eager to take more specimens, until the population was extirpated in 1931.<ref name = "Mateo"/> As no other population was known, the species was presumed extinct.<ref name = "Böhme">Böhme, W., & Bings, W. (1975). Zur Frage des Überlebens von Lacerta s. simonyi STEINDACHNER. ''Salamandra'', 11(1), 39-46.</ref>

===Rediscovery===
[[File:Gallotia simonyi.jpg|thumb|El Hierro giant lizard in captivity.]]
In 1971, the Spanish biologist Alfredo Salvador raised the possibility that the El Hierro giant lizard still existed in Fuga de Gorreta, having collected testimonies of goat herders and finding the excrements of a large lizard himself. However, by 1974 Salvador considered them extinct due to all sightings being older than twenty years. After reading Salvador and earlier literature, a German architect and amateur lizard breeder, Werner Bings,<ref name = "Mateo-Jurado">Mateo, J.A. & López Jurado, L.F. (1999) "La «resurrección» del lagarto de El Hierro (II)." ''Anarda Siglo XXI'', pgs. 36-37.</ref> decided to search for the El Hierro giant lizard himself and take a breeding couple to [[Germany]] in the event of success, once he checked with the Spanish embassy in [[Bonn]] that the species was not listed as protected in Spain.<ref name = "Böhme"/>

Bings interviewed herders and used bait. He found that areas reputedly inhabited by the giant lizard were not occupied by the smaller Boettger's lizard, and also recovered recent excrement from a large lizard. Finally, 72-year old herder Juan Machín gave Bings a partial skeleton with remains of skin still attached. This skeleton was identified in Germany as a juvenile ''G. simonyi'', killed about two years before, although with differences compared to the Roque Chico de Salmor lizards that might warrant different species or subspecies status. Only a few days after Bings left for Germany, on 13 July 1975, Machín caught two lizards in a trap. They were kept alive by a German resident in the island for a couple of days, but when he tried to take them to Germany the [[Government Delegation (Spain)|Government Delegate]] ordered the [[Civil Guard (Spain)|Civil Guard]] to requisition the lizards and release them in the same place they were found. The German [[consulate|consul]] protested the move, arguing that an "extinct" species could not be subject of protection.<ref name = "Böhme"/><ref name = "Mateo-Jurado"/>

The population was immediately studied and photographed by biologists of the [[Cabildo insular|Mancomunidad de Cabildos]], [[Museo Nacional de Ciencias Naturales]], and [[ICONA]]. In 1989, it was described as a distinct subspecies, ''G. s. machadoi'' by Luis F. López-Jurado, one hundred years after the nominate.<ref>López-Jurado, L.F. (1989) A new Canarian lizard subspecies from Hierro island (Canarian Archipelago). ''Bonner Zoologische Beiträge'', Vol. 40, pgs. 265–272.</ref>

==Conservation efforts==
[[File:Gallotia Simonyi at Centro de recuperación del lagarto gigante..jpg|200px|thumb|El Hierro giant lizard at the Guinea conservation center.]]
The El Hierro giant lizard was declared a protected species in 1975. A breeding program began in Guinea, El Hierro in 1986 (since 1995 a [[LIFE programme]] of the [[European Union]])<ref name = "Mateo-Jurado"/> producing hundreds of animals in captivity.<ref name = "Miteco"/> In 1987 the giant lizards' habitat in Tibataje was declared a natural reserve.<ref name = "Mateo-Jurado"/> In 1999, thirty-seven captive bred subadults were released in Roque Chico de Salmor, and two hundred were released in El Julan, El Hierro. Another release was made in 2001 in La Dehesa, also in El Hierro. The population in Roque Chico grew and became established rapidly, but the populations in the latter two require constant monitoring of feral cats to reduce predation.<ref name = "Miteco"/> In 2013, thirty-five were released in Punta de Arelmo and thirty-two in Punta de Agache. It is planned to establish seven population centers, including a second insular one in Roque Grande de Salmor.<ref name = "Salvador"/>

The [[IUCN Red List]] classifies the El Hierro giant lizard in the category of [[critically endangered]] CR B1ab(v)+2ab(v), due to occupying less than 10&nbsp;km<sup>2</sup>, being present in less than 100&nbsp;km<sup>2</sup>, and having a fragmented distribution, although the population is not in decline and has only increased since 2002. This could be reversed, however, if control of feral cats stops. In 2007, a storm destroyed most of the captive breeding center, killing 182 of 268 lizards inside. A new center was built afterward.<ref name = "Salvador"/>

The El Hierro giant lizard is listed on Annex IV of the European Union's [[Habitats Directive]] (EC 2003) and on Appendix I of [[CITES]].

==References==
{{Reflist}}

==Further sources==
* '''[[ARKive]]''' (2006): [https://web.archive.org/web/20060911134930/http://www.arkive.org/species/GES/reptiles/Gallotia_simonyi/ Hierro giant lizard (''Gallotia simonyi'')]. Downloaded on 18 May 2006.
* '''Barahona''', F.; Evans, S. E.; Mateo, J.A.; García-Márquez, M. & López-Jurado, L.F. (2000): Endemism, gigantism and extinction in island lizards: the genus ''Gallotia'' on the Canary Islands. ''[[Journal of Zoology|J. Zool.]]'' '''250'''(3): 373–388. <small>{{doi|10.1017/S0952836900003101}}</small> (HTML abstract)
* '''Bischoff''', Wolfgang (2000): DGHT-AG Lacertiden aktuell: [https://web.archive.org/web/20061007235932/http://www.dght.de/ag/lacertiden/lacertiden1.htm Rieseneidechsen auf La Gomera]. Version of 2000-MAY-23. Retrieved 2007-FEB-25.
* '''Diaz''', Carlos Naeslund & '''Bischoff''', Wolfgang (1994): Studien am Roque Chico de Salmor bei El Hierro (Kanaren): 1. Mögliche Ursachen für das Aussterben von ''Gallotia simonyi'', 2. Die Artzugehörigkeit seiner Geckos (''Tarentola''). ''Salamandra'' '''30'''(4): 246–253. [Article in German] [https://web.archive.org/web/20070928141507/http://www.dghtserver.de/salamandra/artikelanzeige.php?nr=3028 HTML abstract]
* '''[[European Commission]]''' (EC) (2003): ''[http://www.internationalwildlifelaw.org/EUCouncilDirective92.html Council Directive 92/43/EEC on the Conservation of natural habitats and of wild fauna and flora]''. Annex IV - Animal and plant species of community interest in need of strict protection. Treaty of Accession 2003. [https://web.archive.org/web/20060818110659/http://ec.europa.eu/environment/nature/nature_conservation/eu_enlargement/2004/habitats/annexiv_en.pdf PDF fulltext]
* '''[[European Environment Agency]]''' (2006a): [http://eunis.eea.europa.eu/ European Nature Information System (EUNIS)]: [http://eunis.eea.europa.eu/species-factsheet.jsp?idSpecies=687&idSpeciesLink=687 Species Factsheet: ''Gallotia simonyi'']. Downloaded on 24 Feb 2007.
* '''[[European Environment Agency]]''' (2006b): [http://eunis.eea.europa.eu/ European Nature Information System (EUNIS)]: [http://eunis.eea.europa.eu/species-factsheet.jsp?idSpecies=15492&idSpeciesLink=15492 Species Factsheet: ''Gallotia simonyi machadoi'']. Downloaded on 24 Feb 2007.
* '''Maas''', Peter H.J. (2006): [https://web.archive.org/web/20111013123736/http://extinct.petermaas.nl/ The Extinction Website]: Extinctions in Europe. Downloaded on 18 May 2006.
* '''Maca-Meyer''', N.; Carranza, S.; Rando, J.C.; Arnold, E.N. & Cabrera, V.M. (2003): Status and relationships of the extinct giant Canary Island lizard ''Gallotia goliath'' (Reptilia: Lacertidae), assessed using ancient mtDNA from its mummified remains. ''[[Biological Journal of the Linnean Society|Biol. J. Linn. Soc.]]'' '''80'''(4): 659–670. <small>{{doi|10.1111/j.1095-8312.2003.00265.x}}</small> (HTML abstract)

{{Taxonbar|from=Q5874935}}

[[Category:Gallotia]]
[[Category:Reptiles of the Canary Islands]]
[[Category:Reptiles described in 1989]]
[[Category:El Hierro]]