Curly-tailed lizard
Leiocephalus carinatus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Iguania
Clade:	Pleurodonta
Family:	Leiocephalidae Frost &Etheridge, 1989
Genus:	Leiocephalus Gray, 1827[1]

Leiocephalidae, also known as thecurlytail lizards orcurly-tailed lizards, is afamily ofiguanian lizards restricted to theWest Indies. One of the defining features of these lizards is that their tail often curls over. They were previously regarded as members of the subfamily Leiocephalinae within the familyTropiduridae. There are presently 30 knownspecies, all in thegenusLeiocephalus.

Phylogenetic evidence supports Leiocephalidae being the mostbasal extant member of the cladePleurodonta, with it diverging from the rest of the suborder as early as theLate Cretaceous, about 91 million years ago.^[2] As with many other higher-order taxa endemic to the Caribbean, it likely colonized theAntilles from South America during theCenozoic; however, its deep divergence time from other lizards supports a much more complex and less straightforward history in the West Indies compared to other modern taxa.^[3]

Phylogenetic analysis on the genus supports some members of the now-extinct Lesser AntilleanLeiocephalus radiation being the most basal of the recentLeiocephalus, with the last-surviving members of this group,L. herminieri andL. roquetus, sharing traits not present in other curlytail lizards from the Greater Antilles and other areas, such as the absence of enlarged snout scales. The second most basal of the recent curlytail lizards is another recently extinct species,L. eremitus fromNavassa, followed by all other members of the genus fromthe Bahamas andGreater Antilles. Another extinct species from the Lesser Antilles known only fromfossil remains,L. cuneus ofAntigua and Barbuda, is thought to be more closely related to more derivedLeiocephalus from the Bahamas and Greater Antilles, such asL. carinatus,L. greenwayi andL. punctatus, than to the other, more basal Lesser Antillean and Navassa species.^[3]

Curlytail lizards are native to theWest Indies, with theextant (living) species in theBahamas,Turks and Caicos,Cayman Islands,Cuba,Hispaniola (Haiti and the Dominican Republic) and nearby small islands.^[4][5] Additionally,Leiocephalus carinatus andLeiocephalus schreibersii have beenintroduced to Florida.^[6]

Curlytail lizards formerly had a much wider native range, being distributed south toJamaica and east toPuerto Rico and several of theLesser Antilles.^[7] They went extinct in most of this range during theQuaternary extinction orHolocene extinction, with some members of the Lesser Antillean radiation surviving to recent times, perhaps remaining widespread until afterEuropean colonization. The last surviving members of the Lesser Antillean radiation,L. herminieri ofGuadeloupe andL. roquetus ofMartinique, went extinct during the early-mid 19th century.^[3]

The curly-tailed lizards vary in size depending on species, but typically are approximately 9 cm (3.5 in) in snout-to-vent length. These lizards have nofemoral pores, pterygoid teeth, or palatine teeth. Additionally, these lizards are observed to have overlapping scales.^[4]

The curly-tailed lizards mostly forage onarthropods such as insects, but also commonly take flowers and fruits.^[4][8] Large individuals will eat small vertebrates, includinganoles.^[8][9]

As suggested by their name, most species of this family often lift their tail and curl it. This is done both when a potential predator is present and when not present, although in some curly-tailed lizard species it increases when a predator is present. It shows the fitness of the lizard to a would-be predator and—in the case of an attack—draws attention to the tail, which increases the lizard's chance of escaping.^[10][11] Although it has been suggested that it also functions as a territorial display,^[6] studies have been unable to find support for this, as the tail curling does not vary when another member of the same species is present.^[11]

The conservation status of the species in this family varies greatly. Several species, for exampleLeiocephalus carinatus, are common and widespread. Others are rare and highly threatened, especially those restricted to a single small island or a single location on a larger island, like thecritically endangeredLeiocephalus (barahonensis) altavelensis fromAlto Velo Island and critically endangeredLeiocephalus onaneyi fromGuantánamo Province in Cuba.^[5] Primary threats to their survival are habitat loss (for example, expanding agriculture, charcoal production and grazing goats) and introduced predators (for example,small Indian mongoose).^[12][13][14]

Several species ofLeiocephalus are alreadyextinct, including all of the Jamaican, Puerto Rican and Lesser Antillean members of the genus.^[7][15] Some of these are only known from fossil orsubfossil remains and became extinct in thePleistocene orpre-Columbian era, but others such as two Lesser Antillean species and one fromNavassa survived until comparatively recently, during the 19th century.Leiocephalus is the only knownsquamate genus to be entirely wiped out from the Lesser Antilles following European colonization; other reptilian genera that have also seen significant extirpations in the Lesser Antilles, such asBoa orDiploglossus, still retainrelict populations on at least some islands, such asDominica andMontserrat. This mass disappearance ofLeiocephalus from the Lesser Antilles may be due to their inhabitingdry forests inlittoral areas that were heavily exploited anddeforested by early colonists. Few confirmedLeiocephalus fossil remains from after theearly Holocene are known from the Lesser Antilles, which has raised doubts about their being only recently extirpated from this area; however,Leiocephalus fossil bones are small and closely resemble those of other lizard species, which may explain the lack of detection ofLeiocephalus fossil bones from these areas aside from by the most highly trained palaeo-herpetologists.^[3]

In modern times, three species,Leiocephalus endomychus,Leiocephalus pratensis andLeiocephalus rhutidira, have not been seen since the 1960s and 1970s and are recognized as critically endangered, possibly extinct, by theIUCN. They are among the "most wanted"EDGE species.^[13][14][16]

Lizards of this family arediurnal and mostly inhabit fairly open habitats in a generally well-studied part of the world. Consequently, the majority of the species and subspecies already were scientifically described several decades ago. In 2016, the first new curly-tailed lizard since the early 1980s was described. The species was found in the coastal dunes of Bahía de las Calderas in the southwestern Dominican Republic. This species differs from the rest within Leiocephalidae in that its bony parietal table is U-shaped versus V-shaped, the males have 3–4 enlarged post-postcloacal scales versus 2, and there are specific sexual dimorphism trails.^[17]

The following species andsubspecies, listed alphabetically by scientific name, are recognized as being valid by theReptile Database.^[18]

Image	Scientific name	Common Name	Subspecies	Distribution
	Leiocephalus barahonensisSchmidt, 1921	orange-bellied curlytail	L. b. altavelensisNoble &Hassler, 1933 –Alto Velo curly-tailed lizard, Alto Velo curlytail (likely better regarded as a separate species)[19][20] L. b. aureusCochran, 1934 L. b. barahonensisSchmidt, 1921 L. b. beatanusNoble, 1923 L. b. oxygasterA. Schwartz, 1967	Hispaniola
	Leiocephalus carinatusGray, 1827	saw-scaled curlytail, northern curly-tailed lizard	L. c. carinatusGray, 1827 L. c. aquariusSchwartz &Ogren, 1956 L. c. armouriBarbour &Shreve, 1935 L. c. cayensisSchwartz, 1959 L. c. coryiK.P. Schmidt, 1936 L. c. grantiRabb, 1957 L. c. hodsdoniK.P. Schmidt, 1936 L. c. labrossytusSchwartz, 1959, South Central Cuba, Playa Larga L. c. microcyonSchwartz, 1959 L. c. mogotensisSchwartz, 1959 L. c. virescensStejneger, 1901 L. c. zayasiSchwartz, 1959	Bahama Islands, the Cayman Islands and Cuba
	Leiocephalus cubensis(Gray, 1840)	Cuban brown curlytail, Cuban curlytail lizard	L. c. cubensis(Gray, 1840) L. c. gigasA. Schwartz, 1959 L. c. minorVarona &Garrido, 1970 L. c. pambasileusA. Schwartz, 1959 L. c. paraphrusA. Schwartz, 1959	Cuba.
	Leiocephalus endomychusA. Schwartz, 1967	Hinche curlytail, Central Haitian curlytail (possiblyextinct, last seen in 1976)		Haiti
	†Leiocephalus eremitus(Cope, 1868)	Navassa curlytail lizard (extinct, 19th century)		Navassa Island
	Leiocephalus greenwayiBarbour & Shreve, 1935	East Plana curlytail,Plana Cay curlytail lizard		Bahama Islands
	†Leiocephalus herminieri(A.M.C. Duméril &Bibron, 1837)	Martinique curlytail lizard (extinct, 19th century)		Trinidad and Tobago
	Leiocephalus inaguaeCochran, 1931	Inagua curlytail lizard		Bahamas
	Leiocephalus loxogrammus(Cope, 1887)	San Salvador curlytail,Rum Cay curlytail lizard	L. l. loxogrammus(Cope, 1887) L. l. parnelliBarbour & Shreve, 1935	Bahamas
	Leiocephalus lunatusCochran, 1934	Hispaniolan maskless curlytail,Santo Domingo curlytail lizard	L. l. arenicolorMertens, 1939 L. l. lewisiA. Schwartz, 1967 L. l. louisaeCochran, 1934 L. l. lunatusCochran, 1934 L. l. melaenoscelisA. Schwartz, 1967 L. l. thomasiA. Schwartz, 1967	Dominican Republic.
	Leiocephalus macropus(Cope, 1863)	Cuban side-blotched curlytail, Monte Verde curlytail lizard	L. m. aegialusA. Schwartz & Garrido, 1967 L. m. asbolomusA. Schwartz & Garrido, 1967 L. m. felinoiGarrido, 1979 L. m. hoplitesZug, 1959 L. m. hyacinthurusZug, 1959 L. m. immaculatusHardy, 1958 L. m. koopmaniZug, 1959 L. m. lenticulatusGarrido, 1973 L. m. macropus(Cope, 1863) L. m. phylaxA. Schwartz & Garrido, 1967 L. m. torreiGarrido, 1979	Cuba.
	Leiocephalus melanochlorus(Cope, 1863)	Tiburon curlytail,Jérémie curlytailed lizard	L. m. hypsistusSchwartz, 1966 L. m. melanochlorus(Cope, 1863)	Haiti.
	Leiocephalus onaneyiGarrido, 1973	Guantanamo striped curlytail, Guantanamo striped curly-tailed lizard,Sierra curlytail lizard		Cuba.
	Leiocephalus personatus(Cope, 1863)	Hispaniolan masked curlytail, Haitian curlytail lizard		Hispaniola.
	Leiocephalus pratensis(Cochran, 1928)	Haitian striped curlytail,Atalaye curlytail lizard (possiblyextinct, last seen in 1966)	L. p. chimarusA. Schwartz, 1979 L. p. pratensis(Cochran, 1928)	Haiti.
	Leiocephalus psammodromusBarbour, 1920	Turks and Caicos curlytail, Bastion Cay curlytail lizard	L. p. aphretorA. Schwartz, 1967 L. p. apocrinusA. Schwartz, 1967 L. p. cacodoxusA. Schwartz, 1967 L. p. hyphantusA. Schwartz, 1967 L. p. mounaxA. Schwartz, 1967 L. p. psammodromusBarbour, 1920	Turks and Caicos Islands
	Leiocephalus punctatusCochran, 1931	Crooked Acklins curlytail, spotted curlytail lizard		Bahamas.
	Leiocephalus raviceps(Cope, 1863)	pallid curlytail, mountain curlytail lizard	L. r. delavaraiGarrido, 1973 L. r. jaumeiA. Schwartz & Garrido, 1968 L. r. kilinikowskiA. Schwartz, 1960 L. r. raviceps(Cope, 1863) L. r. uzzelliA. Schwartz, 1960	Cuba.
	Leiocephalus rhutidiraA. Schwartz, 1979	Haitian black-throated curlytail, Lapierre curlytail lizard (possiblyextinct, last seen in 1978)		Haiti.
	†Leiocephalus roquetusBochaton, Charles, and Lenoble, 2021	La Désirade curlytail lizard, curlytail roquet (extinct, late 19th century)		Guadeloupe.
	Leiocephalus schreibersii(Gravenhorst, 1838)	red-sided curlytail, red-sided curly-tailed lizard	L. s. nesomorusA. Schwartz, 1968 L. s. schreibersii(Gravenhorst, 1838)	Hispaniola
	Leiocephalus semilineatusDunn, 1920	Hispaniolan pale-bellied curlytail,Thomazeau curlytail lizard, Pale-bellied Hispaniolan curlytail		Hispaniola.
	Leiocephalus sixtoiKohler, Bobadilla, & Hedges, 2016	Hispaniolan dune curlytail		Hispaniola.
	Leiocephalus stictigasterA. Schwartz, 1959	Cuban striped curlytail, Cabo Corrientes curlytail lizard	L. s. astictusA. Schwartz, 1959 L. s. celeustesA. Schwartz & Garrido, 1968 L. s. exotheotusA. Schwartz, 1959 L. s. gibarensisA. Schwartz & Garrido, 1968 L. s. lipomatorA. Schwartz & Garrido, 1968 L. s. lucianusA. Schwartz, 1960 L. s. naranjoiA. Schwartz & Garrido, 1968 L. s. ophiplacodesA. Schwartz, 1964 L. s. parasphexA. Schwartz, 1964 L. s. septentrionalisGarrido, 1975 L. s. sierraeA. Schwartz, 1959 L. s. stictigasterA. Schwartz, 1959	Cuba.
	Leiocephalus variusGarman, 1887	Cayman curlytail, Cayman curly-tailed lizard		Cayman Islands.
	Leiocephalus vinculumCochran, 1928	Gonave curlytail,Cochran's curlytail lizard		Haiti.

• †Leiocephalus anonymousPregill, 1984 –Hispaniola
• †Leiocephalus apertosulcusEtheridge, 1965 –Hispaniola
• †Leiocephalus cuneusEtheridge, 1964 –Leeward Islands curlytail (extinct,Late Quaternary ofAntigua and Barbuda and potentiallyAnguilla,La Désirade, andMarie-Galante, but might have survived to recent times)
• †Leiocephalus etheridgeiPregill, 1981 –Morovis curlytail (extinct,Late Pleistocene ofPuerto Rico)
• †Leiocephalus jamaicensisEtheridge, 1966 – Jamaican curlytail (extinct, Late Pleistocene orHolocene ofJamaica)
• †Leiocephalus partitusPregill, 1981 –Guánica curlytail (extinct,Pleistocene or Holocene of Puerto Rico)

Nota bene: Abinomial authority ortrinomial authority in parentheses indicates that the species or subspecies was originally described in a genus other thanLeiocephalus.

• Gray JE (1827). "A Description of a new Genus and some new species of Saurian Reptiles; with a Revision of the Species of Chameleons".Philosoph. Mag. Ann. Chem. Math. Astron. Nat. Hist. Gen. Sci.2 (9): 207–214. (Leiocephalus, new genus, p. 207).
• Schwartz A,Thomas R (1975).A Check-list of West Indian Amphibians and Reptiles.Carnegie Museum of Natural History Special Publication No. 1. Pittsburgh, Pennsylvania: Carnegie Museum of Natural History. 216 pp. (Leiocephalus species,L. barahonensis –L. viniculum, pp. 126–140).

• Lizard genera
• Leiocephalus
• Taxa named by John Edward Gray

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