Obdurodon+dicksoni+-+Platypus

BACK TO MODERN PLATYPUS ◄ ▬ - --- ▬ ► ** FUTURE PLATYPUS ** By Fioni Chiu

This ancient large spoon-billed platypus was called Obdurodon dicksoni who lived 23 to 10 million years ago, in the early to middle Miocene Epoch period. Obdurodon dicksoni is endemic to Australia, like the Giant Wombat, with water as its survival needs.

__**HABITAT/DISTRIBUTION** __ Most Obdurodon  species are found in central Australia, with a closely related species of //Monotrematum sudamericanum// from the Paleocene of Patagonia in Argentinademonstrates that monotremes like the platypus were once part of the Gondwana fauna. Obdurodon dicksoni’s fossils were found in the Riversleigh area in Northern Australia, -hence the name Riversleigh Platypus. This area would’ve been an environment full of freshwater pools, caves of limestone and lakes, during the Miocene Epoch period. Palaeoecological studies have indicated that there was more open forests and woodland aside from the water channels and more rain forest along side of the water banks. 

-  -   -  __**STRUCTURE **__ Obdurodon dicksoni has a length up to 60 cm long from head to tail which was much larger in size compared to the modern platypus. Unfortunately, only parts of the fossils were found and known only from the Riversleigh World Heritage Fossil Site in northwestern Queensland. They were the skull, the lower jaw and a number of isolated teeth. Obdurodon dicksoni has large functional molar teeth, unlike modern platypuses who do not have teeth, except for their babies who loose them at a young age. The Riversleigh platypus has an abnormally flat, strong, adaptive skull, similar to a crocodile, with fully rooted molars and premolars. Unlike the modern platypus, the lower jaw of the Obdurodon dicksoni was very well developed with angular and coronoid processes. __**DIET** __ <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 110%; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;">The Riversleigh platypus fed on yabbies (freshwater crayfish), insect larvae, other crustaceans and also small vertebrate animals like small fishes and frogs. There is a possibility that the Riversleigh platypus spent a greater amount of time feeding on surfaces, like catching insects on water’s surfaces and smaller amount of time diving deep under water catching invertebrates, as the modern platypus does today. With such well developed teeth, studies suggest that the diet of the Obdurodon dicksoni had a more varied diet with larger prey which include fishes and frogs, unlike the modern platypus. ====<span style="font-family: Tahoma,Geneva,sans-serif;">__<span style="background-color: transparent; color: #000000; font-size: 110%; font-style: normal; text-decoration: none; vertical-align: baseline;">**LIFE CYCLE** __ ==== <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 110%; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;">Obdurodon dicksoni would have been an egg-layer as it is also a monotreme. It is most likely that this platypus made burrows in the banks of rivers and streams, and fed on aquatic invertebrates and insects similar to the modern platypus today. There is no further knowledge of its lifestyle, as the remaining fossils of its skeleton have not been found yet.

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<span style="background-color: #ffffff; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 130%; font-style: normal; vertical-align: baseline;">** __ADAPTATIONS__ ** <span style="font-family: Tahoma,Geneva,sans-serif;">__<span style="background-color: transparent; color: #000000; font-size: 15px; font-style: normal; text-decoration: none; vertical-align: baseline;">**Structural Adaptation ONE:** __ <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; text-decoration: none; vertical-align: baseline;">**Bill** <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;">The bill of the Riversleigh platypus is much larger than the ﻿ bills of platypuses today. The bill acts as a tool that helps the platypus adapt by scraping the sides of river banks and snapping at insects on the surface of the water to find food, mechanically digesting it with its teeth which is used to break down the food. It is likely that the adaptation of the bill was to satisfy the needs of the Riversleigh platypus as food would have been harder to find in the period of where it was found. With a larger bill, the Riversleigh platypus would find it easier to find food from scraping sides of river banks for larger prey to fulfill its diet.

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<span style="font-family: Tahoma,Geneva,sans-serif; line-height: 0px; overflow: hidden;"> <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; vertical-align: baseline;">__**Structural Adaptation TWO:**__ <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; text-decoration: none; vertical-align: baseline;">**Teeth** <span style="font-family: Tahoma,Geneva,sans-serif;"><span style="background-color: transparent; color: #000000; font-size: 15px; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;">From the evidence of the Obdurodon dicksoni ’s fossils, it is shown that this ancient platypus once had both, teeth and horny pads which were used to break up food. The well developed, advanced, rooted teeth of the <span style="background-color: transparent; color: #000000; font-size: 15px; font-weight: normal; text-decoration: none; vertical-align: baseline;">//Obdurodon dicksoni// <span style="background-color: transparent; color: #000000; font-size: 15px; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;"> suggest that it would’ve have had a more diverse diet than the living modern platypus, possibly including larger prey like big fishes, frogs and other underwater invertebrates.This adaptation may have been influenced by where the platypus was living which was the sides of the riverbanks where it could dig for food. The Riversleigh platypus was named Obdurodon dicksoni because the Latin meaning of its name ‘Obdurodon’ meant "enduring tooth".

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<span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; vertical-align: baseline;">__**Behavioral Adaptation ONE:**__ <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; text-decoration: none; vertical-align: baseline;">**Hunting** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 110%;">// Unlike the modern platypus which hunted mostly under water and insects on the surface of water, Obdurodon Dicksoni hunted on sides of river bank, scraping and digging the sides in search for amphibians like frogs and invertebrates which suggests that it had a more diverse diet compared to the platypuses today. It hunted //<span style="background-color: transparent; color: #000000; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;">larger prey like big fishes, frogs and other underwater and ground invertebrates. The skull of the Obdurodon Dicksoni was shaped rather strangely and was unusually flat, similar to the skull of a crocodile. Therefore, it may have shared a few characteristics on how it hunted.

<span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; vertical-align: baseline;">__**Behavioral Adaptation TWO:**__ <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; text-decoration: none; vertical-align: baseline;">**Nocturnal** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 110%;">The Riversleigh Platypus is mainly a nocturnal animal, like the modern platypus. The ancient platypus can best be seen during the early morning and late evening, where it spends most of its time catching food to eat. But, unlike the modern platypus, it does not spend its entire time underwater but on land to dig on the side of riverbanks for food. When it is day, the Riversleigh platypus spends most of the time in their burrows and only become active at dawn, in the very early morning, and at dusk, in the late evening.<span style="background-color: transparent; color: #000000; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;">The only time Obdurodon dicksoni is not alone, is when the platypuses are mating or if the mother is with her young. The Riversleigh platypus does not show much interests in other platypuses unless it is the mating season and rely only on themselves. This adaptation is likely to have happened to protect the Riversleigh platypus from the scorching sun and hunt in the cooler hours of the night, less competition for food, avoid predators that come out in the day in which they may not have been able to escape from and being able to camouflage with its surroundings so it can hide from predators.

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<span style="color: #ffffff; font-family: Tahoma,Geneva,sans-serif;">- <span style="color: #ffffff; font-family: Tahoma,Geneva,sans-serif;">- <span style="color: #ffffff; font-family: Tahoma,Geneva,sans-serif;">- <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 110%; font-style: normal; vertical-align: baseline;">__**Physiological Adaptation ONE:**__ <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 110%; font-style: normal; text-decoration: none; vertical-align: baseline;">**Eggs** <span style="font-family: Tahoma,Geneva,sans-serif;"> Platypus reproduction is very unique and unusual as it lays eggs instead of giving birth to their young like other mammals do. The platypus is one of the only 2 mammals that lay eggs. Each Riversleigh platypus mother produces one to three eggs. Similar to the modern platypuses, the mother typically stays in the burrow, keeps them warm by holding them between her body and tail until they hatch. Females seal themselves inside one of the burrow's chambers to lay their eggs. A mother typically produces one or two eggs and keeps them warm by holding them between her body and her tail. When platypus infants are hatched, they are around the size of a finger nail and are helpless. Females look after the young for 3 to 4 months until they can swim on their own. Laying <span style="background-color: transparent; color: #000000; font-size: 15px; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;"><span style="background-color: #ffffff; color: #000000; font-size: 14px; font-style: normal; font-weight: normal; vertical-align: baseline;">eggs is an adaptation as it the eggs are trapped in the burrows for warmth and are protected from predators that may eat or destroys the eggs.

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<span style="font-family: Tahoma,Geneva,sans-serif;">__ **EXTINCTION PRESSURE** __ <span style="background-color: transparent; color: #000000; font-family: Tahoma,Geneva,sans-serif; font-size: 15px; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline;">The Riversleigh platypus's extinction would have been influenced by the changes in its surrounding environment. There may have been a change in climate in its particular region, where some of the animals in which the platypus lived on could have died out. The Riversleigh Platypus may also had a lack of food supply, where just by scraping sides of riverbanks was not enough to fulfill its appetite or it may had competition between other introduced or non native species, leading into a level where it could no longer support itself. Also, the Obdurodon dicksoni may have not been as well equipped than the modern platypus today, as the competition between larger animals increased. The Riversleigh platypus may have been destroyed by other animals that were stronger or faster at the time.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 130%;">**BIBLIOGRAPHY:**
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">ABC Science - Australian Beasts - Fact files - Riversleigh Platypus. (n.d.). //ABC.net.au//. Retrieved July 20th, 2011, from []
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Obdurodon dicksoni - Australian Museum. (n.d.). //Australian Museum - nature, culture, discover - Australian Museum//. Retrieved June 20th 2011, from []
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">The Riversleigh Fossil Site. //A biography of the Australian continent//. Retrieved June 22nd, 2011, from []
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Professor Paul Nature Encyclopedia - Ornithorhynchidae Platypuses (29/10/2010). Blogspot.com. Retrieved June 25th, 2011, from []
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Digimorph - Monotremes. Monotremes. (n.d). Digimorph.org. Retrieved July 25th, 2011, from []