CLASSIFICATION OF PLATYPUS (ORNITHORHYNCHUS)
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 :-MAMMALIA (Body covered with hairs. females have mammary glands).
Sub-class :- PROTOTHERIA (Egg laying mammals).
Order :- MONOTREMATA (Cloaca present).
Genus : Ornithorhynchus
- Found in South Eastern Australia and Tasmania
HABIT AND HABITAT
- It is a native of rivers, pools and creeks, It burrows to 12 to 15 metres along the river banks, It feeds on fresh-water invertebrates, carried in cheek pouches.
GENERAL CHARACTERSTICS OF PLATYPUS (ORNITHORHYNCHUS)
- Commonly called duck-bill-platypus.
- It measures about 50 cm in length having fine short fur, dark brown colour and combines the characters of a duck with a mammal.
- Body is divided into head, thick trunk and tail, Body and tail contain soft hairs.
- Head distinct. Upper jaw produced to form a flattened beak which is covered with a smooth, hairless skin that forms a free fold at the base of the beak. Head contains nostril mouth and external ear opening.
- Jaws covered with horny plates with out teeth. Pinnae absent.
- Forelimbs and hind limbs have 5 digits, web and clawed toes. Hind limb has horny spur. Tail flattened and adapted for swimming.
- Coracoid and precoracoid present. T-shaped interclavicle.
- Eyes small having nictitating membrane. Mammary glands without nipples.
- Cloaca present. Ureter open in dorsal wall of urinogenital passage. Testes abdominal, penis conducts only sperms. Oviducts distinct, uterus or vagina absent.
Female makes nest of roots and leaves during spring in burrows, lays 1-3 eggs. About 05 cm long young one is hatched. It nurses by lapping up milk secreted by scattered mammary glands on the abdomen of female.
- Ornithorhynchus : Platypus is an egg-laying mammal and exhibits reptilian, mammalian and intermediate characters. Reptilian features are urinogenital system, pre coracoids, absence of pinna and corpus callosum. Mammalian features include hair, diaphragm, 4-chambered heart, 3-car ossicles, etc. Intermediate features include mammary glands without nipples, acromion spines in the scapulae and body temperature between 25 28°C is imperfect thermoregulator.
- This mammal has flat bill and above features, hence it is Ornithorhynchus : Duck- Bill Platypus.