HEMIDACTYLUS : COMMON HOUSE LIZARD

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1) HEMIDACTYLUS : COMMON HOUSE LIZARD

1.1) CLASSIFICATION OF HEMIDACTYLUS : COMMON HOUSE LIZARD

1.2) GEOGRAPHICAL DISTRIBUTION

1.3) HABIT AND HABITAT

1.4) GENERAL CHARACTERSTICS OF HEMIDACTYLUS : COMMON HOUSE LIZARD

1.5) SPECIAL FEATURES

1.6) IDENTIFICATION

1.7) REFERENCES

CLASSIFICATION OF HEMIDACTYLUS : COMMON HOUSE LIZARD

PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present )

Group :- CRANIATA ( Definite head. Cranium with brain present )

Sub-phylum :- VERTEBRATA ( vertebral column present)

Division :- GNATHOSTOMATA ( Jaws and paired appendages present )

Super class :- TETRAPODA ( Paired limbs, lungs, bony skeleton and cornified skin)

Class :- REPTILIA ( Scaly vertebrates with right and left aortic arches. Single condyle, pulmonary respiration. Embryo with amnion and allantois ).

Sub-class :- DIAPSIDA ( Skull with two temporal openings separated by postorbital and squamosal ).

Order :- SQUAMATA ( Lizards and snakes with horny epidermal scales or shields. Quadrate bone movable. Vertebrae procoelous. Anal opening transverse).

Sub-order :- SAURIA ( Lizards. Body slender, limbs 4. Pterygoid in contact with quadrate. Eyelids movable )

FAMILY :- GECKNOIDAE ( Toes provided with adhesive pads).

GENUS :- Hemidactylus

GEOGRAPHICAL DISTRIBUTION

Hemidactylus has world-wide distribution and is chiefly found in India,
Europe, Asia, Africa, United States of America, Sri Lanka and China.

HABIT AND HABITAT

Hemidactylus is a common house lizard found in every home. Nocturnal in habit. During winter they hibernate under wood, logs and crevices of the walls. They are adapted to walk on walls. They feed on insects and small invertebrates. It is a fast runner diapsid.

GENERAL CHARACTERSTICS OF HEMIDACTYLUS : COMMON HOUSE LIZARD

Commonly known as wall lizard.
Body measuring approximately 25 cm in length is slender, covered with minute small scales and divided into head, neck, trunk and tail.
They are ugly looking. Some members contain black and dark grey patches on dorsal surface while others have dark grey dorsal surface. Abdomen is yellowish white.
Head is triangular containing eyes, nostrils and external ear opening. Eyes lack movable eyelids. Tongue protrusible.
Forelimbs and hind limbs well developed. Toes are provided with rounded adhesive pads for climbing.
Many wall lizards produce sound.
Quadrate bone movable. Only supratemporal arch present.
Vertebrae amphicoelous. Egg shells calcified.

SPECIAL FEATURES

The tail if broken from any place it again regenerates, although small in size because vertebrae do not regenerate. Tail contains intervening unossified zones between vertebrae which are easily broken and then regenerated. This is called as caudal autotomy. Wall lizard is adapted to walk on walls, roofs and on smooth surfaces. The walking is effected by the dilated digits, which contain double series of lamellae and work under vacuum principle. The digits are first pressed over wall and then released gently to create a vacuum, by which they remain adhered to wall and are able to walk.