30-729: 18, See text. Teiidae is a family of Lacertoidean lizards native to the Americas. Members of this family are generally known as whiptails or racerunners ; however, tegus also belong to this family. Teiidae is sister to the Gymnopthalmidae , and both families comprise the Teiioidea. The Teiidae includes several parthenogenic species – a mode of clonal reproduction. Presently, the Teiidae consists of approximately 150 species in eighteen genera . Teiids can be distinguished from other lizards by
60-699: A bite and then swallow it whole. Despite being voracious hunters at times, all species pose no threat to humans and will generally avoid interaction in the wild. Being neither poisonous or venomous, their bites are also mild and minor. Skinks are generally carnivorous and in particular insectivorous . Typical prey include flies , crickets , grasshoppers , beetles , and caterpillars . Various species also eat earthworms , millipedes , centipedes , snails , slugs , isopods ( woodlice etc), moths, small lizards (including geckos ), and small rodents . Some species, particularly those favored as home pets, are omnivorous and have more varied diets and can be maintained on
90-491: A female-like role. Individuals can switch roles throughout their life. The claim of pseudocopulation was initially met with hesitation by some researchers, and the behavior has not been observed in all parthenogenetic varieties. Since at least some all-female lineages exhibit pseudocopulation, these lizards can be considered to reproduce unisexually (in contrast to asexually). Teiids are known to have briefly occurred in Europe during
120-492: A general rule, the longer the digits, the more arboreal the species is likely to be. A biological ratio can determine the ecological niche of a given skink species. The Scincidae ecological niche index (SENI) is a ratio based on anterior foot length at the junction of the ulna/radius-carpal bones to the longest digit divided by the snout-to-vent length . Most species of skinks have long, tapering tails they can shed if predators grab onto them. Such species generally can regenerate
150-462: A microscope, all major skink lineages share an old XY system that is over 80 million years old. These X and Y specific regions are highly divergent and contain multiple chromosomal rearrangements and repetitive sequences. Many genera, Mabuya for example, are still insufficiently studied, and their systematics are at times controversial, see for example the taxonomy of the western skink , Plestiodon skiltonianus . Mabuya in particular,
180-554: A purely reptilian placenta directly comparable in structure and function, to a eutherian placenta. Clearly, such vivipary repeatedly has developed independently in the evolutionary history of the Scincidae and the different examples are not ancestral to the others. In particular, placental development of whatever degree in lizards is phylogenetically analogous , rather than homologous , to functionally similar processes in mammals. Skinks typically seek out environments protected from
210-440: A regimen of roughly 60% vegetables/leaves/fruit and 40% meat (insects and rodents). Species of the genus Tristiidon are mainly frugivorous, but occasionally eat moss and insects. Although most species of skinks are oviparous , laying eggs in clutches, some 45% of skink species are viviparous in one sense or another. Many species are ovoviviparous , the young (skinklets) developing lecithotrophically in eggs that hatch inside
240-498: A relatively conserved chromosome number, between 11 and 16 pairs. Skink genomes are typically about 1.5 Gb, approximately one-half the size of the human genome. The Christmas Island blue-tailed skink ( Cryptoblepharus egeriae ) was sequenced in 2022, representing the first skink reference genome. Skinks were long thought to have both genetic sex determination (GSD) and temperature-dependent sex determination (TSD). Despite having sex chromosomes that are not distinguishable with
270-476: A small amount of plant matter in their diet. They are oviparous , and some species lay very large clutches . Several species of whiptail lizards are entirely female and no males are known. These all-female species reproduce by obligate parthenogenesis (obligate, because the lizards do not involve males and cannot reproduce sexually). Like all squamate obligate parthenogenetic lineages, parthenogenetic teiids are hybrids . Two or more species rarely hybridize and
300-472: A variety of habitats worldwide, apart from boreal and polar regions. Various species occur in ecosystems ranging from deserts and mountains to grasslands. Many species are good burrowers. More species are terrestrial or fossorial (burrowing) than arboreal (tree-climbing) or aquatic species. Some are "sand swimmers", especially the desert species, such as the mole skink or sand skink in Florida . Some use
330-463: A very similar action in moving through grass tussocks. Most skinks are diurnal (day-active) and typically bask on rocks or logs during the day. Raccoons , foxes , possums , snakes , coatis , weasels , crows , cats , dogs , herons , hawks , lizards , and other predators of small land vertebrates also prey on various skinks. This can be troublesome, given the long gestation period for some skinks, making them an easy target to predators such as
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#1732863238389360-651: The Late Eocene based on fragmentary fossil material non-diagnostic to the genus level found in the Quercy Phosphorites Formation of France dating to the MP 17 zone. The Teiidae contains approximately 150 species divided into two subfamilies and 18 genera. This assessment includes several recent changes: three resurrected genera, five newly described genera, and the large genus Cnemidophorus split into Aspidoscelis and Cnemidophorus . In some technical literature,
390-483: The Miocene . Skink genera known from fossils include the following: A trait apparent in many species of skink is digging and burrowing. Many spend their time underground where they are mostly safe from predators, sometimes even digging out tunnels for easy navigation. They also use their tongues to sniff the air and track their prey. When they encounter their prey, they chase it down until they corner it or manage to land
420-492: The Solomon Islands skink ( Corucia zebrata ) is the largest known extant species and may attain a snout-to-vent length of some 35 cm (14 in). Skinks can often hide easily in their habitat because of their protective colouring (camouflage). Skinks in the genus Prasinohaema have green blood because of a buildup of the waste product biliverdin . The oldest known skink is Electroscincus zedi described from
450-408: The family Scincidae , a family in the infraorder Scincomorpha . With more than 1,500 described species across 100 different taxonomic genera, the family Scincidae is one of the most diverse families of lizards. Skinks are characterized by their smaller legs in comparison to typical lizards and are found in different habitats except arctic and subarctic regions. The word skink , which entered
480-580: The mongoose , which often threaten the species to at least near extinction, such as the Anguilla Bank skink . Invasive rodents are a major threat to skinks that have been overlooked, especially tropical skinks. Skinks are also hunted for food by indigenous peoples in New Guinea , including by the Kalam people in the highlands of Madang Province , Papua New Guinea. Despite making up 15% of reptiles, skinks have
510-511: The red-eyed crocodile skink have a head that is very distinguished from the body. These lizards also have legs that are relatively small proportional to their body size. Skinks' skulls are covered by substantial bony scales, usually matching up in shape and size, while overlapping. Other genera, such as Neoseps , have reduced limbs and fewer than five toes ( digits ) on each foot. In such species, their locomotion resembles that of snakes more than that of lizards with well-developed limbs. As
540-951: The Caribbean. The origins of the group are unclear. The oldest definitive lacertoid is the amphisbaenian Plesiorhineura , from the early Paleocene of North America. Given that it resembles modern worm lizards, the lacertoids most likely appeared and diversified in the Cretaceous. However, Berriasian taxon Purbicella may be a lacertoid, and would be the oldest known. Within the Laterata there are many species listed on IUCN Redlist conservation status. This family listed 5 species extinct, 31 species critically endangered, 53 species endangered, 40 species vulnerable, 53 species near threatened, and 569 species as least concerned. [REDACTED] Data related to Lacertoidea at Wikispecies Skink For genera , see text . Skinks are lizards belonging to
570-499: The English language around 1580–1590, comes from classical Greek skinkos and Latin scincus , names that referred to various specific lizards. Skinks look like lizards of the family Lacertidae (sometimes called true lizards ), but most species of skinks have no pronounced neck and relatively small legs. Several genera (e.g., Typhlosaurus ) have no limbs at all. This is not true for all skinks, however, as some species such as
600-638: The Lacertidae, in a group named the Lacertibaenia. Lacertoids have a wide geographic distribution. The Lacertidae are found throughout Europe and Asia, with a major radiation endemic to Africa. The Teiidae are diverse in South America, but some members of the group occur in southern North America as well. The Amphisbaenia are especially widespread, occurring in North America, Europe, Africa, South America, and
630-566: The Teiidae are referred to as macroteiids (in opposition to the microteiids, which are members of a sister family Gymnopthalmidae ). Parthenogenetic lineages are generally referred to as species, though the concept of a species is meant loosely. Other terms include array, clone, type, or morph. Lacertoidea The Lacertoidea is a group of squamate reptiles that includes the Lacertidae , Teiidae , Gymnophthalmidae , and Amphisbaenia . The finding from molecular phylogenetic studies that
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#1732863238389660-554: The burrowing Amphisbaenia were nested in a clade with the lizard forms led Vidal & Hedges (2005) to propose a new name for the group based on shared morphogical characters, Laterata , "referring to the presence of tile-like (squarish or quadrangular, and sometimes raised) scales that form the rings in Amphisbaenia, and are also present ventrally in Lacertiformata and Teiformata ". Studies of anatomy have traditionally grouped
690-401: The elements, such as thick foliage, underneath man-made structures, and ground-level buildings such as garages and first-floor apartments. When two or more skinks are seen in a small area, it is typical to find a nest nearby. Skinks are considered to be territorial and often are seen standing in front of or "guarding" their nest area. If a nest is nearby, one can expect to see 10-30 lizards within
720-622: The following characteristics: large rectangular scales that form distinct transverse rows ventrally and generally small granular scales dorsally , head scales that are separate from the skull bones, and teeth that are solid at the base and "glued" to the jaw bones. Additionally, all teiids have a forked, snake-like tongue. They all possess well-developed limbs. Teiids are all terrestrial (few are semi-aquatic) and diurnal , and are primarily carnivorous or insectivorous . Most teiids forage quite actively within their ideal temperature range, quickly skirting between cover objects. Some will include
750-592: The lacertoids with skinks ; however, more recent studies focusing on DNA have placed them as a distinct group of lizards, more closely related to the venomous Toxicofera . The relationships of the Amphisbaenia to other lizards have long been a mystery; although superficially snakelike, their anatomy and locomotion is quite distinct from that of snakes, Amphisbaenia have a reduced right lung as opposed to snakes which have their left lung reduced. However, they do not closely resemble any other group of lizards. Recent molecular studies suggest that amphisbaenians are grouped with
780-501: The lost part of a tail, though imperfectly. A lost tail can grow back within around three to four months. Species with stumpy tails have no special regenerative abilities. Some species of skinks are quite small; Scincella lateralis typically ranges from 7.5 to 14.5 cm (3 to 5 + 3 ⁄ 4 in), more than half of which is the tail. Most skinks, though, are medium-sized, with snout-to-vent lengths around 12 cm ( 4 + 1 ⁄ 2 in), although some grow larger;
810-410: The mid-Cretaceous (late Albian to early Cenomanian ) Burmese amber from Myanmar , dating to around 100 million years ago . Based on the presence of osteoderms , Electroscincus appears to belong to the Scincidae crown group , indicating that some divergence among the extant skink subfamilies must have already occurred by 100 million years ago. Other definitive skink fossils are known from
840-455: The mother's reproductive tract , and emerging as live births. In some genera, however, such as Tiliqua and Corucia , the young developing in the reproductive tract derive their nourishment from a mammal-like placenta attached to the female – unambiguous examples of viviparous matrotrophy . Furthermore, an example recently described in Trachylepis ivensi is the most extreme to date:
870-404: The offspring are thought to occasionally be capable of reproduction without sperm . The meiotic mechanism for bypassing fertilization is an ongoing area of research. Primarily known from lab studies of parthenogenetic Aspidoscelis neomexicanus , simulated mating behavior can increase fertility . In this behavior known as pseudocopulation , one female assumes a male-like role and the other
900-400: The period of a month. In parts of the southern United States, nests are commonly found in houses and apartments, especially along the coast. The nest is where the skink lays its small white eggs, up to 4-8 at a time. Skinks are very specific in their habitat as some can depend on vegetation while others may depend on land and the soil. As a family, skinks are cosmopolitan ; species occur in
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