Author Topic: Monotremes on coins  (Read 1343 times)

0 Members and 1 Guest are viewing this topic.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Monotremes on coins
« on: December 03, 2014, 09:17:10 PM »
From Wikipedia:

Monotremes (from the Greek monos "single" + trema "hole", referring to the cloaca) are mammals that lay eggs (Prototheria) instead of giving birth to live young like marsupials (Metatheria) and placental mammals (Eutheria). The only surviving examples of monotremes are all indigenous to Australia and New Guinea. The existing monotreme species are the platypus and four species of echidnas (or spiny anteaters).

The key anatomical difference between monotremes and other mammals is the one that gave them their name; monotreme means 'single opening' in Greek and comes from the fact that their urinary, defecatory, and reproductive systems all open into a single duct, the cloaca. This structure is very similar to the one found in reptiles. Monotremes and marsupials have a single cloaca (though marsupials also have a separate genital tract), while most placental mammal females have separate openings for reproduction, urination, and defecation.

Monotremes lay eggs. However, the egg is retained for some time within the mother, which actively provides the egg with nutrients. Monotremes also lactate, but have no defined nipples, excreting the milk from their mammary glands via openings in their skin. All species are long-lived, with low rates of reproduction and relatively prolonged parental care of infants. The monotremes also have extra bones in the shoulder girdle, including an interclavicle and coracoid, which are not found in other mammals. Monotremes retain a reptile-like gait, with legs on their sides of, rather than underneath, their bodies.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #1 on: December 03, 2014, 09:18:22 PM »
Australia, 20 cents, 1987.  Duck-billed platypus:  Ornithorhynchus anatinus.
« Last Edit: October 16, 2017, 09:32:29 AM by <k> »

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #2 on: December 03, 2014, 09:21:03 PM »
Australia, 1981 scalloped 20 cents.  Mistakenly struck on Hong Kong 2 dollar blanks by the Royal Mint, UK.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #3 on: December 03, 2014, 09:22:01 PM »
Australia, $200, 1990.  Platypus.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #4 on: December 03, 2014, 09:22:48 PM »
Australia, $5 silver, 2000.  Platypus.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #5 on: December 03, 2014, 09:24:09 PM »
Australia, $50, 2007.  Platypus.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #6 on: December 03, 2014, 09:24:59 PM »
Australia, $100, 2011.  Platypus.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #7 on: December 03, 2014, 09:26:14 PM »
Australia, $2 gold, 2014.  Platypus.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #8 on: December 03, 2014, 09:27:50 PM »
Australia, 5 cents, 1984.  Echidna - spiny anteater.
« Last Edit: October 16, 2017, 01:13:53 AM by <k> »

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #9 on: December 03, 2014, 09:28:37 PM »
Australia, $200, 1992.  Echidna.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #10 on: December 03, 2014, 09:29:20 PM »
Australia, $5, 2000.  Echidna.
« Last Edit: March 16, 2019, 09:49:38 PM by <k> »

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #11 on: December 03, 2014, 09:30:38 PM »
Australia, $100, 2007.  Echidna.

Offline <k>

  • Moderator
  • Honorary Member
  • *****
  • Posts: 20 051
Re: Monotremes on coins
« Reply #12 on: December 03, 2014, 09:31:13 PM »


Papua New Guinea, 5 kina, 2012.  Spiny anteater.  Collector coin.