Unlike other animals, mammals have body hair, have 3 middle ear bones (the malleus, incus, and stapes), and nourish their young with milk that females produce in modified sweat glands that are called mammary glands.
3. Introduction To Mammals
The mammals from the phylogenetically “highest” group of vertebrate animal
kingdom.
It is known that true mammals did emerge by 125 millions years ago,
approximately 40 million years after ‘mammalia formes’ , mammal like
therapsids.
The term “mammal” refers to the Greek words ”Mammae” which means
mammary glands
They include the moles ,bats, rodents, cats ,monkey, whales, horse ,deer and
humans other living forms ,besides a host extinct species and orders.
Mammals include 5400 species (15,000 sub species) and 34 orders.
5. General characters
Have mammary glands.
Have hair and fur on the body.
Mammals are endothermic vertebrates.
Brain highly developed, Cranial nerves 12 pairs.
Four chambered hearts.
Have sebaceous (fat secreting glands), sudoriferus (sweat), and scent glands.
Have heterodont dentations (different types of teeth).
Possess diaphragm.
Possess one single jaw bone.
Respiration always by lungs (pulmonary).
Fertilization internal preceded by copulation.
6. Subclass-1: Protheria
Infraclass1: Eotheria (Extinct)
Order :1 Triconodonta (Extinct)
Carnivores
Cat-sized
Dental formula : I4 C1P(3-4)M(4-5)
I4 C1P(3-4)M(4-5)
with 3 subequal cusps in line. Fig: Triconodon
Ex. Triconodon.
.
8. Infraclass-2: Ornithodelphia (living)
Order: 3 Monotremata (Living)
head
Egg laying mammals. web
No external pinna or ear. horny beak
Teeth only in young ,adults with
horny beak.
Mammary glands without nipples.
Ex. Ornithorhynchus.
Fig: Ornithorhynchus
9. Infraclass-3: Allotheria (Extinct)
Order:4 Multituberculata (Extinct)
Herbivorous, beaver like
Analogus to placental rodents in size and
function. Fig:Taeniolabis
Highly specialized and varied form.
Dental formula : I1+/1 C0P0M2/3
I1+/1 C0P0M2/3
Ex. Ptilodus , Taeniolabis.
Fig:Ptilodus
12. Infraclass 2:-Mertatheria
Order :7 Marsupialia (Living)
Marsupial or broad pouch strong hind
present in females. limb
Mammary glands are strong tail
sebaceous and bearing nipples. Fig: Macropus
Incisor teeth not equal
in the two jaws.
Viviparous.
Ex. Macropus
Fig. Macropus
13. Infraclass 3: Eutheria
Order: 8 Insectivora (Living)
Small and furry animal.
Snout usually long and tapering. nostril
Teeth sharp and pointed. clawed digit
Dental formula : I3 C1P4M3
I3 C1P3M7
Nocturnal and terrestrial.
Ex. Talpa
Fig:Talpa
14. Order :9 Demoptera (Living)
Commonly known as “flying lemurs”
Nocturnal in habit.
Incisor teeth 2/3.
Fore limbs equal and included with a tail.
Ex. Cynocephalus
Fig:Cynocephalus
15. Order: 10 Chiroptera (Living)
Commonly known as
“true flying lemurs”
Fore limbs are modified for flight.
Hind limbs are weak having Fig: Desmodus
clawed digits.
Eyes are small, ears have large pinnae.
Teeth are sharp.
Dental formula: I2/3 C1/1P3/3M3/3 claw
I2/3 C1/1P3/3M3/3 wing
Ex. Desmodus, Pteropus
Fig: Pteropus
16. Order :11 Primates (Living)
Completely hairy and generally
arboreal mammals.
Head turns readily on neck.
Limb bones separate, freely
jointed.
Hands and feet often enlarged,
each with five distinct digits.
Mode of walking is plantigrade. Fig: Ateles
Ex. Torsius, Ateles (spider monkey)
17. Order :12Tillodontia (Extinct)
Skull long, brain case small.
Two pairs of rootless incisors,
cannines minute, molars, low-crowned.
Feet plantigrade, 5 toed, claws large.
Ex.Tilotherium
Fig :Side-view of the skull
of Tillotherium fodieus, with the
lower jaw displaced downwards,
one-fourth of the natural size.
18. Order :13 Taeniodonta (Extinct)
Early forms small, like insective.
Teeth rooted, enamel covered.
Later types larger, skull short and deep.
One pair of incisors, canines large, molars peglike, no roots,
scant enamel.
Ex. Stylinodon, Conorytes
Fig:Stylinodon
19. Order: 14 Edentata (Living)
Includes large fossil ground
sloths and glyptodont.
Feet have well developed claws.
Teeth present or absent.
If present incisors and canines
are always absent. Fig: Bradypus
Ex. Bradypus, Dasypus.
Fig:Dasypus
20. Order :15 Philodota (Living)
Body covered by large over-lapping horny scales.
Hairs are found between scale.
Snout elongated. scales
Teeth are entirely absent.
Nocturnal and burrowing in habits. external ear
The limbs are short bearing five digits. nostril
Ex. Manis (Pangolin)
head
tail
Fig: Manis
21. Order :16 Lagomorpha (Living)
Small to moderate sized mammals.
Two pairs of incisors are present in
the upper jaw, canine absent. pinna
Tail short. head
Soles of feet are hairy, toes bear claws. eye
Ex. Orictolagus. (Rabbit) fore
limb
Fig: Orictolagus
22. Order:17 Rodentia (Living)
Usually small mammals.
Limbs small ,usually with 5 toes and claws .
Incisors single pair, long chisel like ,
canines entirely absent.
Exa. Rattus rattus (Rat) Fig:Rattus rattus
Callosciurus (Squirrel) tail
pinna
neck
Fig: Callosciurus
23. Order :18 Cetacea (Living)
Medium sized to very large aquatic mammals.
Body usually spindle-shaped and fish like.
Head long often pointed without neck.
Eyes are minute.
Ex. Megaptera, Orcinus (killer whale)
Fig:Orcinus
24. Order :19 Carnivora (Living)
Small to large, terrestrial, arboreal or aquatic.
Teeth usually sharp, incisors small, usually 3/3, canine 1/1.
Small toes usually five.
Ex. Panthera tigris (Tiger)
Canine teeth
Fig: Panthera
Fig: Hunting tiger
25. Order :20 Pinnipedia (Living)
Marine carnivores.
Size medium to large, body spindle-shaped.
Limbs flipper or paddle shaped, used in swimming.
Tail is very short.
Ex. Otario (Sea-lion)
Fig: Otario
26. Order :21 Condylarthra (Extinct)
Primitive ungulates, some with cannies.
Cheek teeth with pointed cusps.
Some small-bodied.
Ex. Phenacodus.
Fig: Fossil of Phenacodus
27. Order :22 Litopterna (Extinct)
Of ungulate form, some to sized of camel.
Toes three or one with hoofs.
Upper incisor present
Cheek teeth are well developed, with folded enamel.
Ex. Thoatherium
Fig: Fossil of Thoatherium
28. Order: 23 Notoungulata (Extinct)
Form varied, rabbit sized to 6m long.
Some heavy-bodied. Digit grade, mostly three-toed, with claws.
Teeth varied, incisors large in some, upper molars incurved.
Ex. Toxodon
Fig: Toxodon
29. Order :24 Astrapotheria (Extinct)
Small to large.
No upper incisors, canines and molars large.
Toes five digitigrades.
Ex. Astrapotherium.
Fig:Astrapotherium
30. Order: 25 Tubulidentata (Living)
Body stout, some what a pig like, covered with sparse hairs.
Snout is very long and tubular.
Ears long ,erect and pointed.
Permanent teeth fewer, no incisors and canine, enamel absent.
Exa: Orycteropus
ear
Fig: Fossil of Orycteropus Fig: Orycteropus
34. Order:29 Proboscidea (Living)
Largest and highly specialized terrestrial mammals.
Skin thick and sparsely covered with hairs.
Flexible muscular proboscis present.
Eyes are small and ears are large.
Legs are large and pillar like.
Ex. Elephas large ear
trunk
Fig:Elephas
35. Order:30 Embrithopoda (Extinct)
Size of rhinoceros.
Forelimbs shorter than hindlimbs.
Toes 5,apreading
Small pair on frontals.
Teeth equal- sized.
Ex. Arsinotherium.
Fig:Arsinotherium
36. Order:31 Hyracoidea (Living)
Small rabbit like animals with split snout.
Ears are short and tail is much reduced.
Dental formula : I1/2 C1/0P4/4M3/3
I1/2 C1/0P4/4M3/3 .
Four digit in the fore limbs and
three in hind. Fig: Procavia
Ex. Procavia, Hyrax
37. Order:32 Sirenia (Living)
Aquatic mammals commonly known as “sea cows”
Body stream lined or spindle-shaped.
Forelimbs modified as peddles, hind limb absent.
Teeth with enamel.
Tail flattened with lateral flukes.
Ex. Helicore ,Trichechus peddle
Fig: Trichechus
38. Order:33 Perissodactyla (Living)
Large-sized hoofed mammals.
Teeth are lophodont. head
Legs long foot with odd number of toes.
Ex. Equas cabellus (Horse)
hair
Fig: Equas
39. Order:34 Artiodactyla (Living)
Terrestrial and aquatic mammals.
Fore and hind limbs bear two rarely four digits.
Teeth selenodont or bunodont.
Anters or horns often present on head. Teeth
Ex : Camelus, Hippopotamus.
Fig:Hippopotamus