The terms lizard, gecko, iguana or dragon do not differ from a taxonomic point of view. These are the names attributed to different types of lizards, mainly due to significant differences in size among these reptiles. Lizards can measure a few centimeters long or reach enormous sizes up to 3 meters in length.
Biologically, these reptiles belong specifically to the Squamata order. This is the largest order of reptiles, including lizards, snakes and worm lizards (amphisbaenians). These species are collectively known as squamates or scaled reptiles. Lizards belong to the Larcertilia suborder of reptiles. This suborder includes over 6,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains.
Underground Reptiles – Lizards of the Dibamidae Family
Dibamidae or blind skinks is a family of small to medium-sized lizards that are snakelike with reduced limbs. However, males have very small rear limbs, which they use to hold onto the female at the time of mating. Species of the Dibamidae family live underground, under rocks and fallen tree trunks. These lizards are adapted to dig their own borrows in the ground. In addition, they are blind and lack teeth.
This family is made up of 10 species distributed in two genera: dibamus (which contains almost all species) and anelytropsis. The first genus inhabits Asian and New Guinea jungles, while the second is only present in Mexico. An example of such a lizard is the Anelytropsis papillosus species which is commonly known as the Mexican blind lizard.
Iguanas – Lizards of the Iguanidae Family
Iguana is any of eight genera and roughly 30 species of the larger members of the lizard family Iguanidae. There has been some controversy regarding the classification of Iguanids among researchers. However, there is an agreement that these types of lizards are representative of the Larcertilia suborder and are generally, arboreal (living on trees). Although some representatives of the Iguanidae family are terrestrial, with rudimentary tongues (not prehensile) except for chameleons. Some families are endemic to Europe, Africa, Asia or Oceania, while others can also be found in the Americas.
Within the Lguanidae family, we can mention some representative species such as the green iguana (Iguana iguana). The green iguana can reach up to 2 meters in length. It is mainly an arboreal animal due to its strong claws that aid it in climbing. Another species of that family is the common collared lizard (Crotaphytus collaris), which inhabits parts of the United States and Mexico.
The Iguania contains three groups: the Iguanidae, the Agamidae, and the Chamaeleonidae. The most well known representatives of the third group are the Chameleons. This is a distinctive and highly specialized type of lizards with 202 species described as of 2015. These species have a peculiar characteristic of changing color, in addition to having extraordinary gripping abilities. Chameleons also have very good eyesight for reptiles. Brookesia chameleons (leaf chameleons) are some of the world’s smallest reptiles, with a maximum length of just over 30 mm (1.18 inch). These tiny lizards are native to Madagascar. The Iguania family also includes lizards of the Draco genus, known as flying lizards, flying dragons or gliding lizards. These lizards are characterized by scaly membranes between the forelegs and hindlegs that allow them to glide from tree to tree.
Geckos – Lizards of the Gekkota Family
This type of lizard consists of the Gekkonidae and Pygopodidae groups, and between them they consist of more than 1,200 species. Species of the Gekkonidae group have limbs while Pygopodidae species are commonly known as legless lizards. These lizards are commonly found in tropical areas and in urban habitats. Due to their small size, they are able to live in any home, feeding on insects that frequent the house. The Sphaerodactylus ariasae, commonly called the Jaragua dwarf gecko is known for being one of the smallest reptiles in the world. At the other end of the spectrum, is the New Caledonian giant gecko (Rhacodactylus leachianus), which can reach lengths of 30 centimeters (ca. 12 inches) from snout to vent, or around 36 centimeters (ca. 14 inches).
Lizards of the Scincomorpha (Hodzhakuliidae) Family
Lizards of this type are one of the most numerous groups, with an important variety of species, specifically the Scincidae (skinks) family. Its body is thin and the head is not well-defined. They also have small limbs and a simple tongue. Several species have long tails, which can be detached to distract their predators, as is the case of the common wall lizard (Podarcis muralis). This type also includes lizards of the Gymnophthalmidae family, which are commonly known as spectacled lizards or microteiids. These lizards got their name because they can see with their eyes closed, since the tissue of their lower eyelids is transparent.
Lizards of the Varanidae Family
This group includes large carnivorous and frugivorous lizards such as the Komodo Dragon (Varanus Komodoensis), the largest lizard in the world. It also includes Monitor lizards, such as the Lace monitor (Varanus varius) native Australia. It has the unique ability to be both terrestrial and arboreal, despite its size. A poisonous representative of this group is the Gila monster (Heloderma suspectum) species, which is known for its lethal venom. However, it is not an aggressive animal, so it does not represent a threat to humans.
Are Lizards in Danger of Extinction | Types of lizards
Reptiles in general, as well as all animals, must be valued and respected. Not only because they fulfill important functions within ecosystems, but because of the value of all life forms on the planet. However, lizards are constantly under pressure from current environmental problems, due to the destruction of their habitat and hunting. There are 110 species, four subspecies, and one subpopulation of lizards considered to be critically endangered.
While some of these animals can be poisonous and should be handled with care to avoid accidents, most are harmless. As a general rule, lizards do not pose any kind of danger to humans.