classification of mammals

Theory & practice of classification

CLASSIFICATION OF MAMMALS

Al Quran

And surely we have honoured the children of Adam, and carried them on the land and at the sea, and provided them with good things, and we have made them to excel by an appropriate excellence over many of those we created. (17:70)

And they ask you about the spirit. Say: The spirit is from the command of my Lord, and you are not given ought of knowledge but a little. (17:85)

MAMMALSMammalia is a class of animals within the Phylum Chordata

Mammals are defined as vertebrates that give birth to live young ones (viviparity) ,possess hairs which insulate their bodies and mammary glands for feeding young ones with milk and share a unique jaw articulation.

They also possess a four-chambered heart, a large cerebral cortex, three distinctive bones: [incus, malleus and stapes] in the middle ear, a diaphragm for breathing, heterodont and thecodont dentition, limbs attached under the body, dicondylic skull and acoelous vertebrae.

Mammals also include humans who are the most highly advanced organisms on Earth. Mammal possess complex range of form and function in them; and also the large extent of individual flexibility which they demonstrate through their behavior.


Many earlier ideas have been completely abandoned by Linnaeus and modern taxonomists, among these are the idea that bats are related to birds or that humans represent a group outside of other living things.

Mammalian classification has been through several iterations since Carl Linnaeus initially defined the class. Most significantly in recent years, cladistic thinking has led to an effort to ensure that all taxonomic designations represent monophyletic groups. The field has also seen a recent surge in interest and modification due to the results of molecular phylogenetics.

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CLASSIFICATION OF MAMMALSMammals are actually a class organized into 5420 species; which are further sub-classified into 135 families, 1,000 genera, 29 orders, and 2 subclasses.

While studying these subclasses, we come to know several mammals that were parted some 200-million years ago. These primitive mammals include egg-laying Prototheria (platypus and echidnas being the only survivors) along with live-bearing theria.

George Gaylord Simpson's[1945] "Principles of Classification laid out a systematics of mammalian origins and relationships that was universally taught until the end of the 20th century.


Though field work gradually made Simpson's classification outdated, it remained the closest thing to an official classification of mammals. Various trials have been made to classify mammals

Molecular classification Standardized classification McKenna/Bell classification Luo, Kielan-Jaworowska, and Cifelli classification Simplified classification No classification system is universally accepted; McKenna & Bell (1997) and Wilson & Reader (2005) provided useful recent compendiums.

How do we classify organisms?

Based on Relatedness Overall similarity Use morphology (and genetics) Shared traits are evidence of shared ancestry shared traits: Internal fertilization; most bear live young ones Mammary glands Fur/hair 1 jaw bone 3 bones in ear Endothermy(warmblooded)

Non-mammals dont have these traits Why? Branched off before these traits evolved Help distinguish mammals & non-mammals

Molecular classification AfrotheriaXenarthraBoreoeutheria EuarchontogliresLaurasiatheria

Standardized classification

Subclasses 1. Protheria 2.Theria 2.1Metatheria[marsupial] 2.2Eutheria [placental]

This approach emphasizes an initial split between egg-laying prototherians and live-bearing therians.

No attempt is made in this classification to further distinguish among the orders within these subclasses and infra classes.This system also makes no note of the position of entirely fossil groups.

McKenna/Bell classification

McKenna inherited the project from Simpson and, with Bell, constructed a completely updated hierarchical system, covering living and extinct taxa , that reflects the historical genealogy of Mammalia. and introduced some fine distinctions such as legions and sublegions (ranks which fall between classes and orders).Subclass PrototheriaSubclass TheriiformesSeveral important fossil mammal discoveries have been made that have led researchers to question many of the relationships proposed by McKenna and Bell (1997).

Luo, Kielan-Jaworowska, and Cifelli classificationLuo et al. (2002) summarized existing ideas and proposed new ideas of relationships among mammals at the most basal level. They argued that the term mammal should be defined based on characters (especially the dentary-squamosal jaw articulation) instead of a crown-based definition (the group that contains most recent common ancestor of monotremes and therians and all of its descendants).They also define their taxonomic levels as clades and do not apply Linnean hierarchies.

Sinoconodon- earliest and most basal of mammalsUnnamed clade 1 - a clade that contains all other mammals. These are characterized bydeterminant growthand occlusal features of the cheek teeth.Unnamed clade 2 - a clade containing all living mammals and some fossil relatives. It is characterized by the loss of a postdentarytrough and a widened braincase.Crown-groupMammalia- the group that contains most recent common ancestor ofmonotremesandtheriansand all of its descendants. This group is defined by additional characters relating the occlusion ofmolarsand the presence of a well-developedmasseteric fossaTrechnotheria-Therians,spalacotheriidsand their relatives. They are characterized by features of thescapula,tibia, andhumerus.CladotheriaZatheriaBoreosphenidaEutriconodonta

CLASSIFICATION OF MAMMALSWILSON AND REEDER recognised about 5420 species of living mammals which are further sub-classified into 152 families, 1229 genera, 29 orders, and 2 subclasses.

MOST SPECIES OF EXTANT MAMMALS have already been placed in the classification but approximately 10-12new species continue to be named each year.

Still ,the numbers of genera and species are insignificant in comparison with those for invertebrates. The mammalian classsification presented here is largely that of various authors in WILSON AND READER [2005] and is based on phylogenetic relationships as currently understood.

MAMMALSclassification

Over 70% of mammal species are in the orders Rodentia(blue),Chiroptera(red), andSoricomorpha(yellow)

Subclass Prototheria:Mammals that lay eggs with leathery shells and nourish the young ones with milk from primitive(open) mammary glands. They possess a cloaca like reptiles, have no urinary bladder but possess hairs, No teeth, but single jaw bone5 species in 2 families in Order Monotremata Earliest monotreme: 125 mya

Teinolophos

PROTHERIAFamily Ornithorhynchidae: platypusesFamily Tachyglossidae: Echidnas (spiny anteaters)

platypusesspiny anteaters

PROTHERIA Echidnas are insectivores.They use their long, sticky tongue to catch ants, termites, other insects, and earthworms When attacked, the echidna will quickly burrow into the ground or curl up into a ball

Subclass Theria4470 species in 25 orders Give birth to live young ones Specialized dentition based on diet All continents

Infraclass Metatheria: Marsupials

Body covered with fur; female with marsupium;give birth to extremely immature infants,complete their development in marsupium;poorly developed or absent corpus callosum diaphragm and seven cervical vertebrae are present and the marsupial bone (epipubis) present). 334 species in 7 orders Earliest marsupial: 125 mya

Sinodelphys


Order Didelphimorphia[89/1]

Common opossumsVirginia opossum

Infraclass Metatheria: MarsupialsOrder Didelphimorphia[89/1]Order Paucituberculata[6/1]

shrew opossumslong-nosed shrewopossum

Infraclass Metatheria: Marsupials Order Didelphimorphia Order Paucituberculata Order Microbiotheria[1/1]

monito del montesSouth Americanmonito del montes

Infraclass Metatheria: Marsupials Order Didelphimorphia Order Paucituberculata Order Microbiotheria Order Dasyuromorphia[71/3]

most carnivorousmarsupialsTasmanian devilTasmanian tiger


Order Didelphimorphia Order Paucituberculata Order Microbiotheria Order Dasyuromorphia Order Peramelemorphia[22/3]

eastern barredbandicootbandicoots

Infraclass Metatheria: Marsupials Order Didelphimorphia[89/1] Order Microbiotheria[6 sp/1] Order Paucituberculata[1/1] Order Dasyuromorphia[71/3] Order Peramelemorphia[22/3] Order Notoryctemorphia[2/1]

marsupial molessouthern marsupial mole


Order Didelphimorphia[89] Order Microbiotheria[6 sp/1] Order Paucituberculata[1/1] Order Dasyuromorphia[71/3] Order Peramelemorphia[22/3] Order Notoryctemorphia[2/1] Order Diprotodontia[144/11] [Kangaroos, wallabies, koalas]

Kangaroos

Infraclass Metatheria: MarsupialiaOrder Diprotodontia[11 families] ( Kangaroos, wallabies, koalas Possums ,vombats) Family Macropodidae Family Phascolarctidae Family Vombatidae Family Borramyidae Family Phalangeridae Family Pseudocheridae Family Petauridae Family Tarsipedidae Family Acrobatidae Family Hypsipyrmnitidae Family Potoroidae

Infraclass Eutheria: Placentalia

True mammals which are completely viviparous, with chorio-allantoic placenta and in which complete development takes place in uterus,so mature infants are born,well developed corpus callosum,marsupium absent 4136 species in 21 orders Longer internal gestation Placenta nourishes embryo Single uterus & vagina More developed infants All continents

Earliest Eutherian: Eomaia125 mya

Eomaia

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Infraclass Eutheria: Placentalia Order Cetacea[11/84]

beached humpback whale (Big Sur)

killer whale[whales, dolphins,porpoises]California grey whale

Infraclass Eutheria: Placentals Order Cetacea[11/84] Order Sirenia[5/2]

West African manateeWest Indian manatee(dugongs, sea cows,manatees)dugong

Infraclass Eutheria: Placentals Order Cetacea [11/84] Order Sirenia [5/2] Order Tubulidentata [1/1]

aardvarks

Infraclass Eutheria: Placentals Order Cetacea Order Sirenia Order Tubulidentata Order Pholidota[8/1]

ground pangolinpangolinsIndian pangolin

Infraclass Eutheria: Placentals Order Cetacea[84/11] Order Sirenia[5/2] Order Tubulidentata[1/1] Order Pholidota[8/1] Order Hyracoidea[4/1]

western tree hyrax[hyrax]rock hyrax

Infraclass Eutheria: Placentals Order Cetacea[84/11] Order Sirenia[5/2] Order Tubulidentata[1/1] Order Pholidota[8/1] Order Hyracoidea[4/1] Order Proboscidea[3/1]

[Elephants]

Asian elephant

African elephant

Infraclass Eutheria: Placentals Order Cetacea[84/11] Order Sirenia[5/2] Order Tubulidentata[1/1] Order Pholidota[8/1] Order Hyracoidea[4/1] Order Proboscidea[3/1] Order Pilosa[10/4]

[anteaters & tree sloths] Giant anteater,long tubular snout,bushy tail( C. & S. America)

Infraclass Eutheria: Placentals

Order Cetacea[84/11] Order Sirenia[5/2] Order Tubulidentata[1/1] Order Pholidota[8/1] Order Hyracoidea[4/1] Order Proboscidea[3/1] Order Pilosa[10/4] Order Afrosoricida[51/2] [Tenercs ] Order Soricomorpha[428/4] [shrews and moles]

southern short-tailed shrewEuropean mole

Infraclass Eutheria: Placentals

Order Cetacea[84/11] Order Sirenia[5/2] Order Tubulidentata[1/1] Order Pholidota[8/1] Order Hyracoidea[4/1] Order Proboscidea[3/1] Order Pilosa[10/4] Order Afrosoricida[51/2] Order Soricomorpha[428/4] Order Artiodactyle[240/10] (even-toed ungulates) [Examples;Pigs,hippos, Giraffee,sheep,goats](Nile Hippopotamus)(Central & eastern Africa)

giraffe

Order Artiodactyla: even-toed ungulatesFamily Hippopotomidae (hippopotomuses) 2 speciesFamily Giraffidae (giraffe, okapi) 2 species, both African

Infraclass Eutheria: Placentals1 Order Cetacea[84/11]2 Order Sirenia[5/2]3 Order Tubulidentata[1/1]4 Order Pholidota[8/1]5 Order Hyracoidea[4/1]6 Order Proboscidea[3/1]7 Order Pilosa[10/4]8 Order Afrosoricida[51/2]9 Order Soricomorpha[428/4]10 Order Artiodactyle[240/10]11 Order Perissodactyla[17/3] [ odd-toed ungulates] (Horses,Rhinos and Zebras)

Grants zebraDomestic horseAsian or Indian rhino(Nepal, N.E. India)

Order Perissodactyla (odd-toed ungulates)

19 species in 3 families Asia, Africa, Americas Herbivores

Family Equidae (horses, asses, zebras) 10 species Excellent peripheral vision

Family Tapiridae (tapirs) 4 primitive species

Family Rhinocerotidae (rhinoceroses) Critically endangered

Infraclass Eutheria: Placentals12 Order Scandentia

treeshrews

pen-tailed treeshrewlarge treeshrew

Infraclass Eutheria: Placentals12 Order Scandentia13 Order Dermoptera

Phillipine colugocolugosSunda colugo

Infraclass Eutheria: Placentals Order Scandentia Order Dermoptera 14 Order Chiroptera

leaf-nosed batCoromo black flying foxbats

Infraclass Eutheria: Placentals Order Scandentia Order Soricomorpha Order Dermoptera Order Chiroptera 15 Order Macroscelidea

elephant shrewsblack and rufous elephant shrewcheckered elephantshrew

Infraclass Eutheria: Placentals Order Scandentia Order Dermoptera Order Chiroptera Order Macroscelidea16 Order Cingulata (armadillos)

Nine-banded armadillo( Mexico, C. &S. America, Caribbean)

Three-banded armadilloSouth America

Infraclass Eutheria: Placentals Order Scandentia Order Dermoptera Order Chiroptera Order Macroscelidea Order Cingulata17 Order Lagomropha[92/3] (rabbits, hare, pikas)

Domestic rabbit

Infraclass Eutheria: Placentals Order Scandentia Order Dermoptera Order Chiroptera Order Macroscelidea Order Cingulata Order Lagomropha[92/3]18 Order Rodentia [2278/34]

Domestic rat (aka Norway rat)Domestic mouse (aka feedermice, fancy mice)

Grey squirrel

Order Rodentia: rodents 2278 species/34 families; 40% of mammals Large, continuously growing incisors High reproductive rates Many colonially living 3 groups based on jaw muscles

Cavy-like Squirrel-like Mouse-like

Order Rodentia: rodents

Suborder Hystricomorpha (cavy-like) Suborder Sciuromorpha (squirrel-like) Suborder Mymorpha (mouse-like) 1. Suborder Hystricomorpha (cavy-like) Capybara,porcupine, chinchilla, naked mole rat,guinea pig (Africa, Asia, Americas)

CapybaraDomestic guinea pigChincilla

N.A. porcupine

Order Rodentia: rodents

prairie dogs

Grey squirrelDomestic rat

2 Suborder Sciuromorpha(squirrel-like) Squirrel, beaver, woodchuck, chipmunk, prairie dogs, gophers Global distribution.

3.Suborder Mymorpha (mouse-like) of all mammal species Mice, rats, voles, lemmings, hamsters, gerbils, muskrat.Woodrat (aka pack rat)

Infraclass Eutheria: Placentals Order Scandentia Order Dermoptera Order Chiroptera Order Macroscelidea Order Cingulata Order Lagomropha[92/3] Order Rodentia [2278/34]19 Order Erinaceomorpha[24/1] [hedgehogs]

European hedgehog

long-eared hedgehog

Infraclass Eutheria: Placentals Order Scandentia Order Dermoptera Order Chiroptera Order Macroscelidea Order Cingulata Order Lagomropha[92/3] Order Rodentia [2278/34] Order Erinaceomorpha[24/1]20 Order Carnivora[286/15]

Most meat-eaters, some omnivores, Binocular vision, good sense of smell & hearing

Order Carnivora: carnivores Family Procyonidae (raccoons & allies] Family Felidae [cats, 38 species] Obligatory carnivores e.g Siberian tiger,Sumatran tiger, African lion,Snow leopard,Fishing cat Family Viverridae (civets, genets,mongooses) Family Canidae [wolves ,foxes and jackals]

Kinkajou

Coati (aka coatimundi)

Order Carnivora: carnivores Family Mephitidae Family Nandiniidae Family Hyaenida Family Phocidae Family Eupleridae Family Ursidae [Largest carnivores, Polar bear,Spectacled bear,] Family Ailuridae (true seals) Family Mustelidae (weasels, badgers, & allies) Family Odobenidae[ walruses ] Family Otariidae [Seals, sea lions] Family Herpestidae [mongooses]

., Order Scandentia[20/2] Order Dermoptera[2/1] Order Chiroptera [1116/19] Order Macroscelidea [15/1] Order Cingulata [21/1] Order Lagomropha[92/3] Order Rodentia [2278/34] Order Erinaceomorpha[24/1] Order Carnivora[286/15]21 Order Primates[376/15] Primateshave well developed hands and feet, with fingers and toes, opposable thumb.haveeyes forwards in the head giving them stereoscopic visionLarge brains, flatter faces ,Shorter snoutBased on fossil evidence, the earliest known true primates, represented by the genusTeilhardina, date to 55.8 million years old

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Order Primates: primatesFamily Hominoidea Apes & humans Able to swing below branches,No tail,Larger brain than monkeys, Shorter snoutFamily Hylobatidae [Gibbons]Family Cheirogaleidae[dwarf Lemurs]Family Cercopethicidae[Old world monkeys, Baboons, macaques, guenon]Family Galagidae[Galagos]Family Aotidae [Night monkeys]Family Indriidae[Wooly lemurs]Family Pethicidae [titis and sakis]Family Atelidae [Howlers]

Order Primates: primatesPrimates typically have grasping hands and feet in addition to relatively large brains. They have flatter faces than most other mammals.350 species/15 families

Family Lemuroidea (lemurs]Family Daubentonoidea[aye aye]Family Lepilemuridae [sportive lemurs]Family Tarsiidae [tarsiers]Family Cebidea[Squirrel monkeysBlack howler monkey, New World monkeys]Family Hominidea [ Apes & humans] ( Able to swing below branches,No tail, Larger brain than monkeys,)

Squirrel monkeysBlack howler monkeylemurs

What Distinguishes Humans from Other Animals?

Charles Darwin believed we are similar to animals, and merely incrementally more intelligent as a result of our higher evolution.

But according to Marc Hauser, director of the cognitive evolution lab at Harvard University, in contrast to Darwin's theory of a continuity of mind between humans and other species, a profound gap separates our intellect from the animal kind.

Hauser and his colleagues have identified four abilities of the human mind that they believe to be the essence of our "humaniqueness" mental traits and abilities that distinguish us from our fellow Earthlings. They are: generative computation, promiscuous combination of ideas, the use of mental symbols, and abstract thought.

1. Generative computation Humans can generate a practically limitless variety of words and concepts. We do so through two modes of operation recursive(allows us to apply a learned rule to create new expressions) and combinatorial( mix different learned elements to create a new concept).

2. Promiscuous combination of ideas "Promiscuous combination of ideas, "allows the mingling of different domains of knowledge such as art, sex, space, causality and friendship thereby generating new laws, social relationships and technologies.

3. Mental symbols Mental symbols are our way of encoding sensory experiences. They form the basis of our complex systems of language and communication. We may choose to keep our mental symbols to ourselves, or represent them to others using words or pictures.

4. Abstract thought contemplation of things beyond what we can sense.

IMPORTANT FACTSThe Kittis hog-nosed bat is the smallest mammal weighing no more than 1.5 g (0.05 oz), while the largest mammal in the world is blue whale;

the wolves are known to travel 1,000 sq. km (400 sq. mi); the Naked mole rat do not leave one burrow;

the female Virginia opossums litters up to 27 babies; orangutan gives birth to one live baby.

None of the aspects of these diverse lives of mammals is random. On the other hand, each individual mammal tries to expand its skill and fitness as compared to their other counterparts, .

classification of mammals

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