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 :- AMPHIBIA ( Scaleless glandular skin , have 3 chambered heart , cold blooded, 2 occipital condyles, can live in water and land both )

Order :- URODELA OR CAUDATA ( Scaleless Amphibia having well developed tail, generally with two limbs, with or without external gills and gill-slits in adults).

Sub-order :-  PROTEIDA ( Body depressed, tail with fin, gills permanent, eyelids absent, lungs present and permanently aquatic).

FAMILY :PROTEIDAE (3 pairs of gills and laterally compressed tail. )

Genus :- Necturus


Necturus is found in North America and chiefly in Arkansas and Hudson rivers.


Necturus is an aquatic salamander of rivers and lakes of U.S.A. It is a crawling animal on the bottom. It eats small fishes and invertebrates.



  • Commonly called as Mud puppy or Water dog.
  • Rusty body of animal with blackish spots divided into head, trunk and tail, measuring about 30 to 40 cm in length.
  • Head is depressed and contains small eyes without eyelids, mouth and nostril.
  • Forelimbs and hind limbs are short and weak and provided with four digits only. First digit is lost, limbs are adapted for crawling only on the bottom of the rivers and lakes.
  • Tail laterally compressed and provided with tail fin. It is the main organ of progression.
  • Tympanum and organs of Jacobson absent; lungs present.
  • Behind the head on each side there are three bushy, red-coloured, distinct external gills and two gill-slits. Breathing is by only external gills.
  • Mud puppy mates in autumn when females take up spermatophores deposited by males; lay eggs in May or June. 18 to 180 eggs in nests attached individually by jelly stalks to undersides of stones.
    Nests are guarded by females. Eggs hatch in 38 to 63 days into a larva, which matures in 6 years to full size.

Special features

Adult is supposed to be a permanently neotenic larva with three pairs of external gills, two pairs of gill slits, lateral line, cartilaginous skull, with larval circulatory system and without Jacobson’s organ. Experimentally, metamorphosis in Necturus could not be induced. It is a very
interesting and favourite animal.


This animal contains 3 pairs of external gills, laterally compressed tail and above features, hence it is Necturus.


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