Monotremes and marsupials have a discontinuous distribution across six regions. Monotremes are found primarily in Australia and include the duck-billed platypus and echidnas. Marsupials are more widely distributed, with most species found in Australia and South America. Both groups are thought to have originated in Gondwana over 100 million years ago before its breakup, allowing their dispersal to current regions. Today there are five monotreme and over 270 marsupial species occupying diverse ecological niches across their ranges.

1. ARBAB IHSAN
BS.ZOOLOGY

2. Distribution of Marsupials and
Monotremes in Six Regions
and Emphasize their Origin

3. What are Monotremes?
 Egg laying mammals
 Why called primitive mammals ?
 The mother has fur and produces milk
 Highly modified beaks.
 Monotremes have a single bone in their lower jaw
 Five living monotreme species
 Examples: Duck-billed Platypus, Echidna.

4. Distribution of Monotremes In Australian
Region
 Australia is home to two monotremes: the platypus and the echidna.
 They live only in Australian Region and picular to this region.
 There are two families of monotremes
 Three genera and five species

5. Distribution of Duck-billed Platypus
 Living platypus family
Ornithorhynchidae include one specie
 The platypus is found in Tasmania and
the Australian Alps to lowland areas close
to the sea.
 The platypus is present in all eastern
Australian states in both eastward and
westward flowing river systems,
.

6. Distribution of Echidna
 Echidna include family Tachyglossidae
 Two genera
 Four species of echidna present.
 Found from Australia, Tasmania, and New Guinea

7. Distribution of Short-beaked Echidna
 Tachyglossus aculeatus
 It is also found in New Guinea
 It is critically endangered in
Australia .

8. Distribution of Long-beaked echidna
 The three living species of long-beaked echidnas of genus Zaglossus
 Found only on the island of New Guinea.
 Long-beaked echidnas live at a wide range of elevations, generally
in forested areas and only where human populations are low.
 All three species to be critically endangered because of hunting

9. Distribution of long-beaked echidnas
 Z. attenboroughi specie inhabits a
tiny pocket of highland forest near
Jayapura, Papua, Indonesia.
 Western long-beaked echidna,
which inhabits the Indonesian
province of West Papua
 Eastern long-beaked echidna
inhabits the Indonesian province
of east Papua.

10. Origin of Monotremes
 The fossil record for monotremes is poor.
 These are thought to be develop from
Therapsids.
 Monotremes were present in Australia during
the Mesozoic Era.
 Monotremes originated and diversified in the
Australian/Antarctic section of Gondwana in
early cretaceous period.
 Single dispersal to South America before the
break up of Gondwana

12. Conti….
o Four species related to Platypus have been found in fossil deposits from Australia.
• Skull of Obdurodon dicksoni (CA)
• Opalised jaw fragment of Steropodon galmani(CA)
• Monotrematum sudamericanum (Patagonia).
• Ornithorhynchus anatinus (Austrailia : Tasmania)
o Fossil evidence that Platypus ancestors were once present outside, when a 61-
63MY old fossil tooth was found in Patagonia, in southern Argentina.

13. Conti….
o Unlike the living platypus, the fossil platypuses had functional molar teeth.
o Fossils indicate that the one remaining living species of Platypus is more
specialized, being confined to the river systems of eastern Australia.
o Ornithorhynchus anatinus, found in eastern Australia.
o Oldest known fossil echidna recovered from eastern Australian cave
deposit about17 MY
o Most fossil echidnas (genus Megalibgwilia) of recent epochs represent a
type intermediate between today’s short- and long-beaked families.

14. Lightly built platypus
Spoon built platypus
Duck built platypus

15. What are Marsupials?
• Belonging to the infraclass Metatheria
• The young develop in mother’s pouch thus pouched mammals
• Marsupials are covered with hair.
• Mammary glands are present
• They occupy an enormous range of ecological niches

16. Distribution of Marsupials In Regions
 These are widely distributed in Australian, Nearctic, Neotropical regions and
few specie in Palearctic region.
 Show dis-contineous Distribution
 Have eight families: 6F in Australia & 2F in SA but Few species of 2F in NA
 272 species
 Australia is “Home of Marsupials”

17. Distribution In Nearctic Region
This include four sub-regions: ARC
Alleghany : This includes eastern region of north America and fauna
includes opossum.
Crossed over to North America (late cretaceous) are marsupials such as
opossum (Didelphis virginiana), shrew opossum (Lestoros inca).
 Two families of which few species of marsupials are inhabits in Nearctic
region:
• Didelphidae:1
• Caenolestidae:1
Tree porcupine
nine-banded
armadillo
Opossums

18. Virginia opossum -Didelphis virginiana
 The only marsupial of family Didelphidae found
north of Mexico(CA).
 The Virginia opossum occurs from
southern Canada to northern Costa Rica.

19. Shrew opossum-Caenolestes convelatus
 Caenolestidae
 Seven species are surviving.
 But only one present in NA.
 Also called rat opossum.
 Currently present only in the
northwestern part of the North America.

20. Distribution in Neotropical Region
 It extends south from the Mexican desert into South America as far as the sub-
antarctic zone.
 Called “Home of Opossums”.
 Two families of marsupials present.
Didelphidae (19 genera: 103 species)
Microbiotheriidae (1 genera: 1 specie)
Coenolestidae (3 genera: 6 species)
 110 species of marsupial present here.
 Some(2) migrate to north America (placenta invader, VCC)

21. Patagonian opossum-Lestodelphys halli
Family Didelphidae
One genera & one specie
 found only in south-
central Argentina.

22. Mouse opossum
 Didelphidae
 Genus Marmosa
 More than 55 species /8 genera
 Most abundant members of
the opossum family
 Central and South American

23. Didelphis opossums-Didelphis
 Didelphidae
 Genera Didelphis
 Species five
 Common opossum (D.marsupialis): MC-SA
 Big-eared opossum (D. aurita): ESB- NA
 White-eared opossums: 3 Species.
• D. albiventris in eastern Brazil
• D. imperfecta in Venezuela and the Guianas.
• D. pernigra, found in the Andes .

24. Water opossum-Chironectes minimus
 Didelphidae
 One genera & one specie
 found from Mexico to Argentina
 Adapted to a semiaquatic life.

25. Gray four-eyed opossum-Philander opossum
 Didelphidae
 One genera & one specie
 Found in both Central and South America
 Long tail

26. Brown four-eyed Opossum-Metachirus
nudicaudatus
 Didelphidae
 One genera & one specie
 Found in both Central and South America
 Large head

27. Shrew opossum
 Caenolestidae
 Three genera
 Six species
 Genus Caenolestes with four species
 Other 2 genera with 1 specie each.
 Confined to Andes mountain range of South
America.

28. Distribution in Australian Region
 The largest and most-varied assortment of marsupials
 Home of marsupials
 There are six families picular to this region.
 200 species
 found in Australia, New Guinea ,tansmania, and neighbouring islands
 Families:
Dasyuridae-Dasyurus:71, 20 genera
Macropodidae-Kangaroos: 65
Peramelidae-Bandicoots:22
Phalangeridae-Phalangers: 3
Wombidae-Wombats: 7
Notoryctidae-Marsupial mole: 2

29. Quolls-Native Cat
 spotted-tailed native cat (D. maculatus)
in moist forests of Tasmania and eastern
Australia.
 The eastern native cat (D. viverrinus), in
open country of Tasmania.
 The western native cat (D. geoffroii) in
central Australia
 The northern native cat (D. hallucatus) is
the New Guinea native cat

30. Dunnarts- Marsupial mice
 found in Australia and New Guinea
 Crest-tailed marsupial mouse
 fat-tailed dunnart
 brush-tailed marsupial mice

31. Numbat-Myrmecobius fasciatus
 Sub-family: Myrmecobiidae
 Endangered specie
 found in southwestern corner of Western
Australia.

32. Wallabies
They are native to Australia , new guinae.
 pretty-faced wallaby, or whiptail
 Six species of rock wallabies: RT
 three species of nail-tailed wallabies
 two species of hare wallabies
 three species of scrub wallabie
 three species of forest wallabies

33. Bandicoots
 family Peramelidae
 Bandicoots occur in Australia, Tasmania, New
Guinea, and nearby island
 The long-nosed bandicoot in EA
 short-nosed bandicoots
 long, pig-footed bandicoot

34. Flying Phalanger
 Phalangers are native to the forests of
Australia, Tasmania, New Guinea, and
islands
 six small phalangers
 pygmy glider
 long pen-tailed of New Guinea
 Short-headed glider: 3 species from New
Guinea to Tasmania
 Greater glider of eastern Australia

35. Common Wombat (Vombatus ursinus)
• In southeastern Australia, from southeastern
Queensland through New South Wales and
Victoria into South Australia
• The southern hairy-nosed wombat
• northern hairy-nosed wombat

36. Diprotodon-Giant wombat
 Diprotodon, an extinct species of
giant wombat that inhabited Australia
during the Pleistocene Epoch.

37. Marsupial mole
 family Notoryctidae
 Found in hot sandy wastes of south-central
and northwestern Australia
 N. typhlops
 N. caurinus

38. Distribution in Palearctic Region
 The earliest marsupial fossils are found in Asia.
 Sinodelphys in western Asia
 Move to NA

39. Origin of Marsupials
 A fossil found in China is thought to be an early ancestor of marsupials and dates from 125 million
years ago called Sino-delphys.
 Primitive marsupial shares many features with living marsupials and suggests that marsupials may have
originated in Asia, spread to North America, and later migrated to present-day South America.(
Bridges)
 This migration took them to Antarctica and Australia, which were united on the ancient landmass
Gondwanaland.
 In 1982 scientists identified the only fossil of a land-dwelling mammal ever found in Antarctica as a
marsupial that lived there about 40 million years ago.
 This discovery confirmed the migration of marsupials from South America, where marsupial fossils
date from 65 million years ago, to Antarctica, and to their final destination of Australia, where
marsupial fossils date from about 25 million years ago.

41. Continue
 Some evidence show that marsupials originate in south
America then northward dispersed to north America and
southward to antartic and Australia.
 Later observe that the marsupials decline in north
America.
 But on Australia region, marsupials are more disperse.
 Marsupials have evolved into a great variety of creatures
suited to a wide range of habitats. Through a process
called convergent evolution, the adaptation of marsupials
has paralleled the adaptation of placental mammals to
similar habitats, and developed remarkably similar
physical features.

42. References
 Archer, M., Flannery, T.F., Ritchie, A., and Molnar, R.E. 1985. First Mesozoic
mammal from Australia - an early Cretaceous monotreme. Nature 318: 363-
366
 Culp, G. Richard; “The Geographical Distribution of Animals and Plants,”
Creation Research Society Quarterly, 25[1]:24-27, June 1998.