11th Class Biology Animal Kingdom Class-Mammalia

(L. mamma = breast)

General characters

(1) Hair-clad, mostly terrestrial, air-breathing, warm blooded, viviparous, tetrapod vertebrates.

(2) Limbs 2 pairs, pentadactyle, each with 5 or fewer digits. Hind limbs absent in cetaceans and sirenians.

(3) Exoskeleton includes lifeless, horny, epidermal hairs, spines, scales, claws, nails, hoofs, horns, bony dermal plates, etc.

(4) Skin richly glandular containing sweat, sebaceous (oil) and sometimes scent glands in both the sexes. Females also have mammary glands with teats producing milk for suckling the young.

(5) Endoskeleton thoroughly ossified. Skull dicondylic having 2 occipital condyles. Cranium large. A single zygomatic arch present. Pterygoids small, scale-like. Otic bones fused into periotic which forms tympanic bulla with tympanic. Each half of lower jaw made of a single bone, the dentary, articulating with squamosal of skull Vertebrae with terminal epiphyses and flat centra (acoelous). Cervical vertebrae usually 7. Ribs bicephalous. Coracoid vestigial.

(6) Teeth are of several types (heterodont), borne is sockets (thecodont) and represented by two sets (diphyodont).

(7) Respiration always by lungs (pulmonary). Glottis protected by a fleshy and cartilaginous epiglottis. Larynx contains vocal cords.

(8) Heart 4-chambered with double circulation.

(9) Kidneys metanephric.

(10) Brain highly evolved. Both cerebrum and cerebellum large and convoluted. Optic lobes small and 4 in number called corpora quadrigemina. Corpus callosum present connecting both cerebral hemispheres. Cranial nerves 12 pairs.

(11) Senses well developed. Eyes protected by lids, the upper of which is movable. External ear opening protected by a large fleshy and cartilaginous flap called pinna. Middle ear cavity with 3 ear ossicles?malleus, incus and stapes. Cochlea of internal ear spirally coiled.

(12)  Sexes separate.

(13) Fertilization internal preceded by copulation.

(14) Except egg-laying monotremes, mammals are viviparous, giving birth to living young ones.

(15) Development uterine.

Classification of Mammalia :  Mammals have been thoroughly described and adequately classified. The main characters forming the basis of their classification into orders include : 

(1) Mode of caring of their young,

(2) Nature of dentition

(3) Foot posture,

(4) Nails, claws and hoofs,

(5) Complexity of nervous system and

(6) Systematics.  

(a) Subclass I prototheria : (Gk. protos = first ; therios = beast). Primitive, reptile-like, oviparous or egg-laying mammals.

Order 1. Monotremata : (Gk. monos = single ; trema = opening), Cloacal opening present Confined to Australian region.

Examples : Monotremes. Platypus or duckbill (ornith orhynchus) spiny anteater (Tachyglossus = Echidna).

 

(b) Sub class II. Theria : (Gk. ther, = animal)

Subclass Theria is divided into two infraclasses : Metatheria and Eutheria.

Infraclass 1. Metatheria : (Gk. meta = between or after)

(1) Metatherians are pouched mammals; young born in very immature state.

(2) Corpus collosum absent.

(3) Epipublic bone present.

Order 2. Marsupialia : (Gk. marsypion = pouch).

(1) Born in a very immature state, and complete their development attached to teats or nipples in the abdominal pouch or marsupium. (2) Usually 3 premolars and 4 molars in each jaw on either side. (3) Vagina double

Examples : Opossum (Didelphis). Kangaroo (Macropus),

koala (Phascolarctos)

• Kangaroo is the native of Australia.

 

 

Infraclass 2. Eutheria : (Gk. eu = true ; therios ; beast)

(1) Higher viviparous placental mammals without marsupium.

(2) Young born in a relatively advanced stage.

(3) Dentition never exceeds \[\frac{3.\,14.3}{3.\,14.3}=44\] . On the basis of characteristics like skull, teeth and limbs, eutheria is arranged into 16 orders.

Order 1. Insectivora : (L. insectum = insect ; vorare = to eat)

(1) Small mammals with long pointed snout.

(2) Feet plantigrade, usually 5?toed, with claws.

(3) Molars with pointed, peg-like cusps for insect feeding.

Examples : Talpa, Sorex, Solenodon, Erinaceus, Paraechinus

Order 2. Dermaptera : (Gk. derm = skin ; pteron = wing).

(1) Nocturnal in trees.

(2) A gliding mammal called flying lemur, resembling a flying squirrel.

Examples : One living genus Cynocephalos (= Galaeoithecus) with 2 species from South eastern Asia.

Order 3. Chiroptera : (Gk. Cheiros = hand ; pteron = wing)

(1) Flying mammals or bats in which forelimbs are modified into wings.

(2) Hind legs short and included in wing membrane.

Examples : Pteropus, Rhinolophus, Desmodus

Order 4. Edentata : (L. edentatus = toothless) Teeth absent or reduced to molars. Without enamel

Examples : Mryrmecopha, Dasypus, Bradypus.

 

Order 5. Pholidota : (Gk. pholis = a scale)

 

(1) Body covered with large overlapping scales with sparse hair in between. No teeth.

(2) Tongue long and protrusible, used to capture insects.

Examples : Single genus of scaly anteaters pangolins (Manis)

 

Order 6. Rodentia : (L. rodo = gnaw).

 

(1) Largest order including usually small gnawing mammals.

(2) Each jaw with one pair of long, rootless, chisel-like incisors growing throughout life.

(3) Canine absent.

Examples : Rattus, Mus, Funambulus.

Order 7. Lagomorpha : (Gk. logos = hare ; morphe = form)

With a second pair of small upper incisors behind first pair of large chisel like incisors. No canines.

Examples : Oryctolagus, Lepus, Ochotona.

 

 

Order 8. Carnivora : (L. caro = flesh ; vorare = to eat) Small to large predatory, flesh-eating mammals.

Examples : Canis familiaris, C. lupus, C. aureus, Odobenus, Phoca, Panthera tigeris.

Order 9. Cetacea : (Gk. ketos or L. cetus =a whale)

(1) Large marine fish-like mammals well adapted for aquatic life pectoral limbs modified into broad paddle-like flippers.

(2) Tail divided in two broad horizontal fleshy flukes with a notch, used in propulsion.

(3) No claws, no hind limbs and no external ears.

(4) Mostly gregarious and carnivorous. The living Cetacea are divided into two suborders Odontoceti (toothed whales) and Mysticeti or Mystacoceti (whalebone whales).

Examples : Phocaena, Orcinus, Delphinus, Platanista Physeter, Balenoptera.

 

 

Order 10. Sirenia : (Gk. siren = sea nymph).

(1) Large, clumsy herbivorous, aquatic mammals with paddle-like forelimbs, no hindlimbs and a flattened tail with horizontal lateral fleshy flukes with or without a notch.

(2) No external ears.

(3) Muzzle blunt. Hairs few.

(4) Stomach complex.

(5) Inhabit estuaries and coastal sea.

Examples : Trichechus, Dugong (Halicore), recently extinct Steller's sea-cow (Rhytina).

 

 

Order 11. Tubulidentata : (L. tubulus Tube like ; dens = tooth) With tubular mouth tongue protrusible, no incisor or conines, limbs clawed and adapted for digging ant and termites nests.

 

 

Examples : Single genus of pig-like aardvark or Cape anteater (Orycteropus) of South Africa.

Order 12. Proboscidea : (Gk. pro = in front ; boskein = to eat)

(1) Largest living land animals having large heads, massive ears, thick practically hairless skins (pachyderm).

(2) Bulky straight legs and 3 to 5 toes with small, nail like hoofs.

(3) Conspicuous feature is the nose and upper lip modified as an elongated flexible proboscis or trunk. 2 upper incisors elongated as ivory tusks.

(4) Cheek teeth lophodont.

Examples : Elephas maximus, Loxodonta africana, Elephas cyclotis.

Order 13. Hyracoidea : (Gk. hyrax = shrew ; eidos = form)

Small, guinea-pig like mammals distantly related to elephants. No canines. Cheek teeth lophodont.

Example : Hyrax (Procavia) from S. Africa, Syria and Arabia.

Order 14. Perissodactyla : (Gk. perissos = odd ; dactylos = toes)

The odd-toed hoofed mammals or ungulates have an odd number of toes (1 or 3) incisors present in both jaws.

Examples : Equus cabalus, Equus asinus, Equus zebra

Order 15. Artiodactyla : (Gk. artios = even ; dactylos = digit)

(1) The even-toed hoofed mammals having an even number of toes (2 or 4)

(2) Incisors and canines in upper jaw usually lacking.

(3) Stomach 4 - chambered.

(4) Many with antlers or horns.

Examples : Sus, Hippopotamus amphibius, Camelus, Cervus, Moschus, Ovis.

 

 

Order 16. Primates : (L. primus = of the first rank)

(1) Generalized or primitive mammals except for the great development of brain. 

(2) Mostly arboreal.

(3) First digit usually opposable, an adaptation for grasping.

(4) Eyes typically large and turned farward.

Example - Gibbon, Mandrillus, Chimpanzee, Ateles, etc.

 

 

 

Common Names

Canis familiaris	Dog
Felis domestica	Cat
Panthera leo	Lion
Panthera tigris	Tiger
Acinonyx jubatus	Cheetah
Lutra	Otter
Herpestes	Mongoose
Trichechus	Manatee
Halicore	Dugong
Equus caballus	Horse
Equus asinus	Ass
Rhinoceros unicornis	Indian rhinoceros
Diceros bicornis	African rhinoceros
Tapirus Indicus	Malayan Tapir
Hippopotamus amphibius	Hippopotamus
Camelus dromedarius	Arabian camel
Cervus	Red deer
Giraffa camelopardalis	Giraffe
Sus scrofa	Wild boar
Bubalus bubalis	Water buffalow
Ateles paniscus	Spider monkey
Macaca mulatta	Rhesus monkey
Macaca silenus	Lion-tailed macaque
Hylobates lar	Gibbon
Papio	Baboon
Presbytis	Langur
Pongo	Orang-utan
Pan	Chimpanzee