The island night lizard (''Xantusia riversiana'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

night lizard Night lizards (family Xantusiidae) are a group of small scincomorph lizards, averaging from less than to over snout–vent length. Most species are viviparous (live-bearing), with the exception of those in the genus '' Cricosaura''. The fami ...

native to three of the

Channel Islands of California The Channel Islands () are an eight-island archipelago located within the Southern California Bight in the Pacific Ocean, off the coast of California. The four Northern Channel Islands are part of the Transverse Ranges geologic province, and ...

San Nicolas Island San Nicolas Island ( Spanish: ''Isla de San Nicolás''; Tongva: ''Haraasnga'') is the most remote of the Channel Islands, off of Southern California, 61 miles (98 km) from the nearest point on the mainland coast. It is part of Ventura Cou ...

Santa Barbara Island Santa Barbara Island (Spanish: ''Isla de Santa Bárbara''; Tongva: ''Tchunashngna'') is a small island of the Channel Islands archipelago in Southern California. It is protected within Channel Islands National Park, and its marine ecosystem ...

, and San Clemente Island. A small number of island night lizards also live on Sutil Island, near Santa Barbara Island.

Etymology

The specific name, ''riversiana'', is in honor of James John Rivers (1824–1913), a London-born physician and naturalist, who was Curator of Natural History at the University of California.Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (''Klauberina riversiana'', p. 222).

Subspecies

The San Clemente Island population is a recognized

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 ...

, the San Clemente night lizard (''Xantusia riversiana reticulata'').

Conservation status

The Island night lizard was listed as a threatened species under the

Endangered Species Act The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of ec ...

(ESA) in the United States since 1977; the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

(IUCN) lists the species as vulnerable. In 2006, the

US Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...

, the administrating agency for the ESA, removed the San Clemente subspecies from the ESA. Better control of munitions-sparked wildfires may have been a reason. In March 2014, The US Fish and Wildlife Service removed the species from the Federal List of Threatened and Endangered Wildlife. This removal was attributed to the removal of non-native animals such as cats and goats from the islands and partnering between the US Fish and Wildlife Service and the US Navy.

Habitat

The island night lizard's preferred

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

is coastal scrub made up of dense boxthorn and cacti thickets.

Reproduction

Like other

s, the island night lizard bears live young rather than laying eggs. The island night lizard is much larger than another species in the genus ''Xantusia'', the

desert night lizard The desert night lizard (''Xantusia vigilis'') is a night lizard native to the Southern California Eastern Sierra and the San Gabriel Mountains into Baja California, southern Nevada, southwestern Utah and extreme western areas of Arizona. Des ...

(''Xantusia vigilis'') of southern California.

Description

Island night lizards are typically between in length, not including the tail. They typically live between 11 and 13 years, but some individuals are estimated to have lived 30 years or more. Their color varies from pale ash gray and beige to brown and black. They may have uniform, mottled, and striped patterns.

References

Sources

* "Island Night Lizard Removed from Endangered Species List Due to Recovery." ''Pacific Southwest Region - US Fish & Wildlife Service''. United States Fish and Wildlife Service, 31 Mar. 2014. Web. 24 Apr. 2014. .

* Behler JL, King FW (1979). ''The Audubon Society Field Guide to North American Reptiles and Amphibians''. New York: Alfred A. Knopf. 743 pp. . (''Xantusia riversiana'', p. 551 + Plate 408). * Boulenger GA (1885). ''Catalogue of the Lizards in the British Museum (Natural History). Second Edition. Volume II. ... Xantusiidæ ...'' London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xiii + 497 pp. + Plates I-XXIV. (''Xantusia riversiana'', p. 327). * Cope ED (1883). "Notes on the Geographical Distribution of Batrachia and Reptilia in Western North America". ''Proc. Acad. Nat. Sci. Philadelphia'' 35: 10–35. (''Xantusia riversiana'', new species, pp. 29–32). * Smith HM (1946). "A subspecies of the lizard ''Xantusia riversiana'' ". ''J. Washington Acad. Sci.'' 36 (11): 392–393. (''Xantusia riversiana reticulata'', new subspecies). *Smith HM, Brodie ED Jr (1982). ''Reptiles of North America: A Guide to Field Identification''. New York: Golden Press. 240 pp. (paperback), (hardcover). (''Klauberina riversiana'', pp. 84–85). * Stebbins RC (2003). ''A Field Guide to Western Reptiles and Amphibians, Third Edition''. The Peterson Field Guide Series ®. Boston and New York: Houghton Mifflin Company. xiii + 533 pp. . (''Xantusia riversiana'', p. 309 + Plate 35 + Map 76). * Stejneger L, Barbour T (1917). ''A Check List of North American Amphibians and Reptiles''. Cambridge, Massachusetts: Harvard University Press. 125 pp. (''Xantusia riversiana'', p. 64). {{Taxonbar, from=Q2707030 Xantusia Reptiles of the United States Endemic fauna of California Fauna of the Channel Islands of California Fauna of the California chaparral and woodlands Lizards of North America Reptiles described in 1883 Taxa named by Edward Drinker Cope