Classification of vertebrate zoology ( class Mammalia)

Class Mammalia;

Mammals are endothermic vertebrates that take hair and make nutrition to feed their young ones. Mammals are said to be arise one fifty million years ago from reptiles. The morganucodontidae were consider earliest mammals that appeared at past Triassic, some 205 million year ago. Mammals may be seen virtually everywhere on earth. Approximately 6,495 species of mammals are present throughout the world.

Features Of Class Mammalia;

Mammals are endothermic animals that have hair on their bodies and make nutrition to feed their young ones. The mammal skin is the organ that develop fabric and at some species horns, claws, nails and hooves. They are also having several kind of glands on their skin surface such as sweat glands and sebaceous glands. However the female mammals have memory gland that are specified to produce nutrition. Mammals with external ear, pinna and dicondylic skull. In mammals teeth are thecodant, dipodont, heterodont and limbs are pentadactyle. Their heart is consist of four chambered with complete separation of oxygenated and deoxygenated blood, however sinus venosus is absent. The brain of mammals are well develop. The male mammals with a distinct copulatory organ, such as penis and extra abdominal testes, contained in the scrotal sacs. Mammals are mostly viviparous except Prototheria. The embryo is attach with the uterine wall by placenta. They are exhibit postnatal care.

 Classification of Mammals;

The class Mammalia is differentiated into three subclasses;

Subclass 1. Prototheria;

The earlier egg laying mammals are include in class of Prototheria. In these mammals mammary glands are present but without teats. They are very similar to humans, the most common type of Prototheria is small sized primates called the Parthenon. Rats, guinea, pigs, monkey, apes, porcupines, rabbits and humans are belong to this subclass.

Subclass 2. Metatheria;

In subclass of Metatheria are present those mammals in which the young ones are born with premature condition and undergo further development in an abdominal pouch, such as marsupial. The mammary glands of marsupial are with teats or Nepal, which open in the marsupium. The testes in these mammals are extra abdominal and lie above the penis, however the uterus and vagina both are paired structures. Furthermore in these mammals true allantoic placenta are absent. This subclass consist of single order Marsupila that’s include opossum, koala as well kangaroo.

Subclass 3. Eutheria;

In Eutheria includes true mammals with true placenta and capable to give birth to their young ones. They are having well develop mammary glands with nipals. In these mammals cloaca are absent, while anus and urogenital aperture are separate. They are having extra abdominal testes that enclosed in the scrotum. Their eggs are small and yolkless, however the embryo is develop inside the uterus and it is get nourished by the true allantoic placenta. This subclass is differentiated into the following orders;

Order 1. Insectivore;

It is small order of mammals including nocturnal animals either arboreal or burrowing. Shrew, hedgehog and mole belong to this order.

Order 2. Dermaptera;

The mammals that include in this order are nocturnal in habit. The flying lemurs are present in order.

Order 3. Chiropetra;

In order Chiropetra includes true flying mammals with pairs of   wings. Their wings are in the form of pair of folds integument that is extending between the second digit of the forelimbs and tails. The example of Chiropetra is fruit bat, flying fox and vamprine bat.

Order4. Edentata;

In this order includes nocturnal as well solitary mammals some of which lack of incisors and canines. The example of this order sloth and armadillo.

Order 5. Pholidota;

The mammals with long snout and potrusible tongue present in this order. Their body covered with an exoskeleton of epidermal scales. These mammals are burrowing and nocturnal in habit. The example of Pholidota are scaly anteater or pangolin.

Order 6. Perrisodactyla;

In this order hoofed and unguligrade foot posture mammals are present. These mammals are herbivore in nature. Such as Zebra, horse, Rhinoceros and Tapir.

Order 7. Hyracoidea;

The mammals that are present in this order having plantigrade fore feet with four toes and hind with three second toe of hind limb with nails and other claws. Hyrax is the example of hyracoidean.

Order 8. Rodentia;

These are small size herbivore mammals having plantigrade foot posture, digits ending claws. Rat, Squirrels and mice include in order Rodentia.

Order 9; Lagomorpha;

These are rodent like mammals having plantigrade foot posture but their hind limbs strongly adopted for jumping. These are include rabbits as well hares.

Order 10; Proboscida;

These mammals are having nose and upper lip that is produced into long proboscis. Elephant is example of proboscida.

Order 11; Tubulidentata;

These are pig like anteater with long snout and an elongated sticky tongue. Aardvark include in this order.

Order 12; Cetacea;

In Cetacea aquatic fish like mammals are present their forelimbs modified into the flippers for purpose of swimming while hind limbs of these mammals are absent. Dolphin, Porpoises and Whale are example of cetacean.

Order 13; Sirena;

These mammals are having aquatic mode of life therefore the forelimbs of these mammals are modified into the flippers for swimming purpose.

Order 14; Carnivora

As name indicate these mammals are carnivores in nature with digitigrade or plantigrade foot posture. Cat, Dog, Bear, Wolf, Lion, Fox and Hyena are belong to carnivore.

Order 15; Primata;

Initially the primates was consider the arboreal mode of life however later on these are said to be returned on land. Their forelimbs are modified for the holding while digits with flat nails. Apes, monkey, lemur and man are belong to primate.