Squamata

Squamata-01

Slavoia darevskii

Trachylepis maculilabris mating

Elaphe quadrivirgata

Central fusion and terminal fusion automixis

Number of snake envenomings (2007)

Squamata is the largest order of reptiles, encompassing lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates. This order is characterized by the presence of scales or scutes covering the body, a lack of a bony secondary palate, and a unique jaw and skull structure that allows for a high degree of mouth opening. The evolutionary history of squamates dates back to the Late Triassic period, making them a highly diverse and widespread group with over 10,000 species.

Characteristics

Squamates are distinguished by their unique skull structure, which allows for the movement of the upper jaw independently of the skull by means of a hinge. This adaptation, along with a mobile lower jaw, enables many squamates, particularly snakes, to consume prey much larger than their heads. Their skin is covered in overlapping scales made of keratin, which aids in water retention and protection from predators.

Classification

The order Squamata is divided into three suborders:

• Serpentes (snakes): Characterized by their elongated bodies, lack of limbs, and specialized jaw structure for consuming large prey.
• Lacertilia (lizards): This diverse group includes species with a wide range of sizes, shapes, and habitats. Many lizards have the ability to regenerate lost tails.
• Amphisbaenia (worm lizards): These are legless, burrowing reptiles, not to be confused with worms or snakes, with a distinctive cylindrical body.

Habitat and Distribution

Squamates can be found in a wide variety of habitats, including deserts, forests, grasslands, and aquatic environments. They are distributed across all continents except Antarctica, showcasing their adaptability to different environmental conditions.

Reproduction

Squamate reproduction can be oviparous (egg-laying), ovoviviparous (producing eggs that hatch within the female's body), or viviparous (giving birth to live young). The method of reproduction varies widely among species and can be influenced by environmental factors.

Conservation

Many squamate species are facing threats from habitat destruction, pollution, climate change, and collection for the pet trade. Conservation efforts are crucial to protect these reptiles and their ecosystems.

See Also

• Reptile
• Evolution of reptiles
• Herpetology