Ichthyophis

Contents hide

1) Classification of Ichthyophis

2) Geographical distribution

3) Habit and habitat

4) General Characteristics of Ichthyophis

5) Special features

6) Identification

Classification of Ichthyophis

Phylum :- Chordata (Dorsal tubular nerve cord, notochord 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, cornified skin and bony skeleton.)
Class :- Amphibia (Cold blooded. Scaleless glandular skin. Can live in water and land. Two occipital condyles, Heart three chambered)
Order :- Gymnophiona or apoda (Vermiform Amphibia without limbs or limb girdles..)
Family :- Ichthyophiidae
Genus :- Ichthyophis

Geographical distribution

Ichthyophis is distributed in tropical regions and found in Sri Lanka, Philippines, Borneo, Java, Scychelles, Mexico to Argentina and India (Mysore) and is the only representative of Gymnophiona living today in tropical countries.

Habit and habitat

Ichthyophis lives in burrows and leads a fussorial life in moist ground. The animal is blind and adapted for burrowing life. It feeds on invertebrates.

General Characteristics of Ichthyophis

Commonly called as caecilian.
Animal is worm-like and slender, measuring about 30 cm in length. Body divided into head, trunk and tail.
Body is covered with a smooth, slimy and transversely ringed skin consisting of small calcified scales arranged in transverse rows. Squirt glands in skin discharge an irritating fluid.
Head contains eyes, nostrils and a pair of sensory tentacles. Tympanic membrane, tympanic cavity and columella absent.
Eyes small, functionless and covered by skin. Though reduced but contain all the parts. A small protrusible tentacle is present between eye and nostril.
Skull compact, roofed with bone.
Limbs and limb girdles absent. Vertebrae amphicoelous.
Laryngotracheal chamber is prolonged into a distinct trachea. Right lung elongated, while left lung is reduced. Anus is sub-terminal.
Males are provided with eversible copulatory organ, which shows advanced characters. Fertilization internal. Male’s cloaca is everted like copulatory organ. Eggs are laid in moist burrows. Mother coils around eggs till they hatch into tadpoles.

Special features

Ichthyophis resembles Amphibia in having a 3 chambered heart, conus arteriosus, urinogenital organs and brain like Amphibia. But it differs from living Amphibia in having scales in dermis and meroblastic eggs. The animal also shows parental care, as the females take care of the eggs by keeping them in the coils of the body, till they hatch. It shows combination of primitive and advanced characters. The former characters include dermal scales in the skin and number of dermal bones in the skull. Loss of limbs, short post-anal part and copulatory organs are specialized characters.