Subclass metatheria Marsupalia or Dipelphia Presence of marsupium

Subclass; metatheria (Marsupalia or Dipelphia) • Presence of marsupium. Females have ventral pouch, the marsupium or brood pouch in the abdomen. The young born in an immature state after a short period of intrauterine development, is kept in this pouch and fed with milk by the mother. • marsupium is supported by epipubic bones (marsupial bones) and encloses teats. • Mammary glands bear teats/ nipples. • Young at birth are tiny, immature, blind and nude

• In pectoral girdle interclavicle absent • Thoracic Ribs are bicephalous (2 heads)tuberculum & capitulum • Diplocondylian skull with small cranium • In most cases, tympanic bone is ring like, so tympanic bulla is absent and tympanic cavity is mostly open. • Vertebrae with epiphyses.

• Corpus callosum absent, cerebral hemispheres small and olfactory lobes are large. • Toes are syndactylous (united) or didactylous (free). In Peramelidae and Phalangeridae the 2 nd and 3 rd toes are enclosed by a common sheath, forming a combing organ. This condition is called syndactyly. In others all toes are separate and not united. This condition is called didactyly. • Stomach large, saccular and caecum well developed in many herbivores.

• Dentition is monophyodont, with the exception of milk molar which will be replaced by the last pre-molar. Incisors more numerous than placentals. • In females, the Uteri and vaginae of the two sides remain separate and unfused. So uteri and vagina are doubled (didelphic condition). • Testes descend in to a pre-penial scrotum except in Notoryctes.

• In both sexes there is a urinogenetal aperture. • Viviparous, majority are aplacental (without placenta). • Body t varies from 32 -36 ºC.

Eg. Macropus. Kangaroo (Pouched mammal) • Are found in the grassy plains of Australia, Tasmania and S. America. • Kangaroo (Macropus giganticus) is the largest of living marsupials. • They are herbivorous and gregarious. • When stands kangaroo is about 6 feet high. • Head and neck are small. • Ear lobes, trunk, hind-limbs and tail well developed

• Dentition polyprotodont, with 5 incisors, 3 premolars and 4 molars in each half of upper jaw and 3 incisors, 3 premolars and 4 molars in each half of lower jaw. So the dental formula is 5/3. 0/0. 3/3. 4/4. • Forelimbs very short and ends in 5 digits bearing claws. • Hind-limbs are 4 toed. Hallux (big toe) is absent in the foot. The 2 nd and 3 rd toes may be united by integument. The 4 th toe is very long and strong and armed with a powerful claw. It is used as a defensive weapon.

• The long and strong tail supports the body at rest and help to balance the body in fast movement • Kangaroo is quadruped while walking and biped in running. • It takes long and rapid leaps on hind-limbs, balancing the body on tail. • The pinnae are long and movable. • Macropus are characterised by the presence of brood-pouch or marsupium on their ventral side.

• Usually a single offspring is born at a time. Gestation period very short ie 30 -40 days. The immature young is naked, blind about 25 mm long. • It is kept in the brood pouch and fed with mothers milk from mammary glands which open in to the pouch. It grows and comes out within 4 -6 months.

Subclass: Eutheria or Placental mammals) • True placental mammals. • Prolonged intra-uterine development with highly organised allantoic placenta • Mammary glands well developed with teats / nipples. • marsupium and marsupial bones (Epipubic bones) absent. • Ribs double headed - tuberculum and capitulum. • Cloaca absent. Urinogenital organs open independently of the rectum.

• large cerebral hemispheres, corpus callosum is well developed. • Neopallium is highly specialised, forming cerebral cortex • Tympanic region protected by tympanic bulla • The general dental formula is 3/3. 1/1. 4/4. 3/3. in pholidota and some Edentates teeths are absent • Testis are usually contained in scrotal sacs placed at the sides or behind the penis.

• Monadelphic condition with single uterus and single Vagina. • Eutherians belong to 16 orders. Orders ; Insectivora, Chiroptera, Dermoptera, Edentata, Pholidota, Primates, Rodentia, Lagomorpha, Cetacea, Carnivora, Tubulidentata, Hyracoidea, Proboscidea, Sirenia, Perissodactyla, Artiodactyla

1. Order ; Insectivora Comprises both living and extinct forms Includes heterogenous collection of Small, mostly nocturnal mammals. • Most are insect eaters. • Most inactive of all mammals. • Long flexible pointed snout projecting beyond the lower jaw. • Feet usually 5 toed with claws. • Teeth sharp and pointed. • Dental formula i 3/3, c 1/1, pm 4/4, m 3/3.

• Placenta discoidal. • Nocturnal, many are terrestrial (burrowing) some arboreal and a few aquatic. • High prodigality of reproduction- so multiple births. Numerous teats. • Many insectivores undergo hibernation in winter. • Eg shrews, moles, hedgehogs etc • Insectivores are absent in Australian and polar regions. .

Eg. Paraechinus (Indian hedgehog) • Is the common hedgehog found in the plains of S. India. • It is nocturnal (hides in holes or bushes during daytime and coming out at dusk for feeding). • It feeds on insects, worms, fruits, roots etc. • Dorsally body is covered by sharp, erectile and movable spines which are modified hairs. Body ventrally covered by soft fur. • It has a very small tail.

• Normal litter size of hedgehog is 4 -7. • It raises its spines and rolls in to a ball when alarmed. • Their spines cause irritation to enemies • They have some immunity to snake-bite and other toxins. • Paraechinus hibernate in winter.

2. Order ; Chiroptera. • Includes bats, only Mammals capable of true flight. • Nocturnal. Active during twilight and night time. They spend day by hanging head downwards from various objects like branches of trees, caves, crevices of rocks etc by claws of one or both the feet. • Fore-limbs are modified for flight. • The wings or patagia are lateral extension of membraneous skin supported by greatly elongated and slender fingers of the forelimbs (except the thumb) and sides of body from shoulder to thumb. • Thumb and its claw is used for clinging.

• Hind limbs are weak with knees turned backwards and have clawed digits. • Eyes small with weak vision. • Organs of hearing and touch well developed. In certain bats, there are foliaceous appendages called nose leaves around nostrils which are highly sensitive. • Ears have large pinnae. • The sternum has a keel for the attachment of wing muscles. • Placenta is discoidal.

• Mammae are pectoral and 1 or 2 pairs. • Only one young is born at a time and is carried by the mother on its lower side. • 3 major groups of bats- insectivorous, frugivorous and sanguivores (blood feeders). • In sanguivores teeth, tongue, oesophagus and the entire digestive system is specialised for blood-feeding. • Upper incisors modified in to flat and razoredged cutting blades • They feed the blood of mammals and large birds.

Eg; Pteropus (Flying fox) • Commonly called “flying fox”, because of foxlike head, long snout & large eyes. • Is the largest of all bats and fruit eating (frugivores) (wing spread over 1. 5 m) • Body covered with brown fur.

• The thumb clawed. • Pteropus occurs in India, Sri lanka, Australia, Africa & Madagascar. Flight adaptations of bat • Wing- like patagia (membraneous extension of skin) for flight • Exceptionally elongated fingers to support and spread out the patagia. • Large powerful pectoral muscles to operate the patagia. • Keeled sternum for the attachment of pectoral muscles

• Fusion of bones in the pectoral girdle to give strength and support to the movement of patagia. • Long and slender bones to reduce body weight. • Hollow limb bones containing large medullary cavities to reduce body wt. • Ability for eco-location, for homing and navigation. It helps to avoid collision with obstacles during flight.

3. Order ; Dermoptera • Membranes or patagium stretched between head and fore limbs, forelimbs and hind limbs and between hind limbs and tail. • All the limbs are equal in size. • Incisors 2/3 and are characteristic being laterally expanded. • They are nocturnal, herbivorous and arboreal in habits.

Eg; Galaeopithecus • commonly called as “Flying lemur” • Asiatic mammal found in the forests of Malayan archipelago and Philippines. • It is about 70 cm long • It is nocturnal and arboreal. • It feeds on leaves and fruits. • Galaeopithecus rest like bats suspended by hind limbs. • Limbs are short with grasping digits.

• Fold of skin called Patagia extends between the neck & fore limbs, fore limbs and hindlimbs and bet hind-limbs and tail. • The patagium is covered with hairs both above and below. • It glides through air by extending the patagia. • the fingers are not elongated and the patagia are not flapped in flight.

• 4). Order; Primates • Most highly evolved animals in terms of brain development, intelligence, memory and reasoning powers. • Omnivorous and generally arboreal mammals. • Hairs cover the entire body except the palms, sole and parts of face. • Hands and feet are more or less prehensile. • 5 digits on each hand foot and are provided with flat nails instead of claw.

• Thumb and great toe are shorter and opposable to the other digits. • Orbits are directed forwards (instead of directed laterally) • Mode of walking is plantigrade. • Clavicles are always present. • Testes are enclosed in scrotum. • 2 pectoral mammae usually with teats. • Cerebrum is large and convoluted. • Placenta discoidal or metadiscoidal and haemochorial.

• • Eg; Loris Tail-less, slow moving, nocturnal primate with short, dense, soft fur, large eyes and thin rounded ears. Limbs are thin, nose projects beyond the lower jaw. It is omnivorous feeding on fruits, leaves, insects, eggs and birds. They belong to 2 genera namely Loris (slender Loris) and Nycticebus (slow Loris)

• Slender Loris- small slender, cute-looking , arboreal, nocturnal primate restricted to S. India and Sri Lanka. • slender loris is earthy brown in colour • Eyes and ear lobes are large, limbs are long and lean • Slow moving animal • 2 sp - L. tardigradus and L. malabaricus. • L. tardigradus is found in the forests of Kerala, Tamil nadu, Karnataka and Andhra Pradesh

• L. malabaricus is slightly smaller and darker than L. tardigradus and is found in the forests of Malabar, Wynad and Coorg. • Slender Loris is an endangered sp. Trapping it for experimental purposes and killing it for medicinal purposes have severely affected its population.

Slow Loris (Nycticebus) –is widely distributed throughout East Indies and is about the size of a small cat. • Several sp. Nycticebus coucang is found in the tropical forests of north-eastern India including Assam. • Endangered sp now.

• Body of slow loris is stout, fur-covered • Head rounded, ears large, eyes large and rounded, each encircled by dark brown ring. • Tail rudimentary, digits well developed for grasping • Nocturnal, omnivore feeding on leaves, tender shoots, fruits, insects

2. Eg; Orang-utan • Anthropoid ape found in forests of Borneo & Sumatra. • Only a single sp Pongo pygmaeus (Simia satyrus). • Orangutans are the largest arboreal mammal, Average weight of male 75 kg and female 40 kg. • Its body covered by reddish or yellowishbrown coat instead of black in Chimpanzee & Gorilla. • Face usually devoid of hair but adult male sometimes have long red beard.

• • Face with prominent blue-black cheek pads especially in male. Very quiet animal, movements usually slow. Spends most of the time on trees Make sleeping nests on trees. Mainly frugivore Territorial animal. Not gregarious.

5). Order; Carnivora • Includes mostly flesh-eating predatory mammals. • Characteristic Dentition. Teeth modified for cutting and tearing flesh of prey. • Incisors are small, usually 3/3, canines are large and pointed, premolars have cutting edges. The last premolars in the upper jaw and the 1 st molar in the lower jaw have blade like cusps which work like blade of scissors. These teeth are called carnassial or sectorial teeth.

• living canivores are grouped in to 2 suborders. Fissipedia and Pinnipedia. • Fissipedians include terrestrial carnivores. They are fast running, digits are separate and clawed. Carnassial teeth are characteristic. Eg- dogs, wolves, foxes, jackels, hyaenas, bears, lion, tiger, cheetah, cats etc. • Pinnipedians are aquatic carnivores with fusiform body, paddled limbs, webbed digits, extra fingers and toes (hyperdactyly). • without carnassial teeth, Pinnae are reduced or absent. Eg- walruses, seals and sea-lions.

Eg; 1. Leo sp Lion (Panthera leo) • The lion (Panthera leo) is a large carnivorous mammal (big cat) native to Africa and S. Asia. • It belongs to Genus Panthera and family Felidae • 2 nd largest member of the cat family next to tiger. • Only wild-cat that lives in family groups. • A full grown lion is about 1 m high at the shoulder and 3 m long including the tail. • Lioness is smaller than lion. Adult lion can be easily recognised by its mane. Females and young males lack mane.

Lions prey on grazing mammals like antelops, Giraffs, zebras, cattle etc • They have sharp retractable claws and teeth adapted to killing animals • Since they feed on grazing mammals they live in more or less open places and not in dense forests. • They rarely climb on trees • Unlike most carnivores, lion hunt during day and night.

• Lions live singly, in pairs or in small groups called prides. A pride of lions (4 - 12 members) consists of related females their offspring or young ones and an adult male. Groups of female lions typically hunt together. • Litter size 1 -4

• Lions live for 10– 14 years in the wild, although in captivity they can live more than 20 years. In the wild, males seldom live longer than 10 years, as injuries sustained from continual fighting with rival males greatly reduce their longevity • At present lions are restricted to the Gir forests of Gujarat and open bush areas in Africa, South of Sahara.

6). Order; Cetacea • Completely aquatic animals, adapted for life in water (oceans, estuaries, rivers, lakes etc) • Include whales, dolphins and porpoises. • Body usually spindle shaped • Hairy covering of skin is reduced to few bristles in muzzle • Neck absent • Nostrils on top of head and ear openings minute, ear lacks pinna. • Fore-limbs modified as paddles and hindlimbs absent.

• tail long, ending in 2 transverse fleshy flukes notched in the middle line. • A thick layer of fat (blubber) is present beneath the skin. • Bones of skull are spongy and contain fat • Network of blood vessels, retia mirabilia, lie in various parts of body for storing O 2 to be used while under water. • There is no sweat or oil glands • Placenta is non-deciduate and diffuse • Carnivorous and mostly gregarious.

Eg; Dolphins • Dolphins are relatively small cetaceans • Upper jaw forms a beak which distinguishes them from porpoises. • Common dolphin (Delphinus delphis) is cosmopolitan in distribution ( found in the Bay of Bengal). • It grows up to 2. 5 m and has characteristic streaks on the flanks. • Platanista gangetica is Indian river dolphin inhabiting the Ganges and Indus. • Dolphins have high intelligence • They produce voccal sounds which are used in echo-location • hearing is very Keen

7). Order; Perissodactyla • Perissodactyle (means uneven toes) • Perissodactyles are odd-toed (1 or 3 toes), hoofed ungulate mammals • Ungulate mammals- The mode of progression is unguligrade, ie the animals walk on the tips of the digits with the heels raised from the ground • Include Terrestrial herbivores like Horse, Tapir, Zebra, Rhinceros etc. • Have long limbs adapted for swift running. • The axis of the limb passes through the 3 rd digit which is always larger than the rest • No horns on the head. • Stomach simple, caecum large and sacculated

eg; Equus • Equus cabalus (domestic horse) is a large, fast running animal having a single functional digit (3 rd), which is enclosed in a solid hoof. • 2 nd and 4 th digits reduced • 1 st and 5 th completely absent • Tail completely covered by long hair • Smaller head, well developed mane on the neck, shorter ears and broader hoofs. • They live in herds • molars specially well-developed for grinding plant food.

• Equus hemionus (Indian ass) has proportionately large head. • Mane insignificant • Tail has hair towards the distal half only • Equus zebra (zebra) is found in herds on grassy lands of Africa. • It has conspicuous black and yellow stripes.