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DISPLAYING POSTS TAGGED: palaeontology (12)

Dino Might

Author
by Wayne
Publish date
24 September 2013
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In the late 1970’s and early 80’s, I was absolutely mad for dinosaurs. Many hours were spent poring over my small stash of dinosaur books - I used to lie on our worn lounge room carpet, gawping at fantastical images of a vengeful Triceratops skewering a clearly outraged Tyrannosaurus in the thigh. To my young eyes, the image was evocative and powerful, albeit a little coy in the lack of blood.

By today’s standards, the picture is quite out-dated in the postures of the protagonists, but it was enough to get me hooked on these intriguing (and like me, clearly ill-tempered) animals. My chief interests wavered over the following teenage years – at times Dinosaur Jr. were more interesting than dinosaurs - but dinos were always there in one way or another, bubbling away as a topic of interest in the back of my mind.

Qantassaurus Melbourne Museum's animatronic reconstructions of the Victorian dinosaur Qantassaurus
Image: Jon Augier
Source: Museum Victoria
 

Fast forward to today, and much has changed – my son sees CGI footage of dinosaurs that are so plausible that there’s genuine confusion over what is actually real. To his generation, it will likely seem ludicrous that our generation thought of Velociraptor as anything other than fully feathered, but to those of us of the “Jurassic Park” generation, the leathery-skinned versions will be long remembered. Disappointingly, it seems that despite scientific consensus on their feathers, the upcoming Jurassic Park film will feature the old-school, oversized, nude ‘raptors. But I digress...

Velociraptor skull A model of the skull of Velociraptor - feathers not shown....just like in Jurassic Park (I might need to get over this)
Image: John Broomfield
Source: Museum Victoria
 

Unlike Hollywood, the scientific world’s understanding of dinosaur behaviour, posture and lifestyles has changed over the years. There are numerous examples of dinosaur displays in Museums that required modification to keep them up-to-date with current research. One of the quirks of palaeontology - the active study of long-since-inactive animals - is that we can never really ‘get it right...finally’; the most we can hope for is to ‘get it right...for now’. New discoveries drive new interpretations, leading to new theories; forever edging us closer to the truth, but the goalposts are constantly moving.  With dinosaurs, you can never ‘know’ everything - and I find that quite reassuring.

Of wreckage, ships and dinosaur bits

Author
by Wayne
Publish date
26 July 2013
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I stare out to sea, a heaving blur of grey with white-capped breakers. Two thoughts occur to me – why didn’t I bring better wet weather gear, and how did this place get this odd name?

view of the ocean A lovely, clear Autumn day onsite at Eric the Red
Image: Wayne Gerdtz
Source: Museum Victoria
 

I am perched on a rock in a sheltered pocket of the beach and near some dune vegetation, the wind and rain intermittently reminding me of my inadequate clothing. Between myself and the sea is a small pile of grey rock which I have been progressively breaking open with my hammer and chisel, searching for fossils. A few metres beyond some of my fellow crew are swinging sledgehammers at a large section of this rock, working on extracting more material to be broken down in a search for more fossils.

Digging at Eric the Red site A group of volunteer diggers brave the elements onsite at the 'Eric the Red' fossil dig.
Image: Wayne Gerdtz
Source: Museum Victoria
 

We are sitting on a beach near the Cape Otway Lighthouse in late March, close to a location called “Eric the Red”. The grey rock we are processing were once sediments laid down in a streambed in a rift valley over 100 million years ago. Amongst the grey sediments are seams of fossilised plant material, and very occasionally, fossil bones of animals that lived and died nearby.

A rock onsite at Eric the Red A rock ready for breaking onsite at Eric the Red - who knows what fossils it might yeild? As it turns out - none.
Image: Wayne Gerdtz
Source: Museum Victoria
 

I am here as part of a Museum Victoria field trip to collect these fossils; amongst me is a wonderfully diverse group of people; Palaeontology students and academics, Museum staff, amateur enthusiasts and assorted interested folk. Together, our aim is to process this Cretaceous rock, search for fossil bone, record our finds and package them carefully for their voyage to the Museum Victoria Palaeontology collections, housed in the Royal Exhibition Building in Carlton Gardens.

But...’Eric the Red’? What’s that name all about?

Weeks later, in the decidedly more dry and comfortable setting of the Museum, I decide to research why the site is called “Eric the Red”. It turns out that ‘Eric the Red’ was a vessel that was shipwrecked close to the shoreline of where we were digging; it ran aground in 1880 on a reef composed of the very same unit of rock we were excavating. The vessel was wrecked on the final leg of its otherwise uneventful voyage from New York to Melbourne, carrying a cargo of exhibits for the USA pavilion at the 1880 Melbourne International Exhibition – silverware, toys and pianos were among its diverse manifest. An interesting coincidence was that the ultimate destination for the Cargo of the Eric the Red was the Royal Exhibition Building in Carlton Gardens in Melbourne – this is also the destination for the fossils we were extracting from the site, as Museum Victoria’s Palaeontology Collections and laboratory are in the basement of the Exhibition Building.

Royal Exhibition Building The Royal Exhibition Building - the intended destination of the cargo of Eric the Red, and in part, home to Museum Victoria's Geoscience collections
Image: Museum Victoria
Source: Museum Victoria
  

Thankfully the fate of our diggers and our precious cargo was less tragic than that of the crew and cargo of the ‘Eric the Red’; the wreck resulted in the loss of life of some crew. You can read a full account of the wreck of “Eric the Red” on Heritage Victoria’s website, and also a the reportage of the tragedy in “The Argus” via Trove.

Geology of the Flatrocks site

Author
by Lisa
Publish date
28 February 2012
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Lisa works in the Public Programs Department at Melbourne Museum but also volunteers in the Palaeontology Department and has been on several fossil digs.

By the tenth day of the annual Dinosaur Dreaming dig we had already catalogued more than 140 fossils. To know where to dig in the first place we need to understand the geology of the area because the types of rock and how they have been laid down can give us much information about the palaeoenvironment. Dr Alan Tait, Adjunct Research Fellow in the Department of Geosciences at Monash University is currently researching the sedimentology of the Flatrocks site and kindly explained its geology to me.

Today the site known as Flatrocks is a rocky beach dominated by light grey sandstone but 120 million years ago during the Cretaceous, the environment was very different. Australia was once part of a supercontinent called Gondwana which also comprised Antarctica, South America, Africa, New Zealand and India.

Much of Gondwana had broken up by the Cretaceous and a rift had started to form between Australia and Antarctic. The types of rocks and fossils we find along the coastline in Inverloch today tell us the story of the rift valley and the animals and plants that lived there.

The cliff face near the Flatrocks site The cliff face near the Flatrocks site. The grey mudstone is the remains of a flood plain which was on the floor of the rift valley. The layer where we find most of our fossils lies above this and at the top is massive sandstone. To the left of the mudstone you can see a fault where the rock layers have shifted dramatically from their original horizontal deposition.
Image: Lisa Nink
Source: Museum Victoria

The fossil layer itself consists of the sedimentary rocks, grey sandstone and conglomerate that were deposited during flooding of the rift valley. The conglomerate pebbles are made of clay eroded from the flood plain soils during flooding. The sandstone is grey because it contains grains of volcanic rock eroded from active volcanos some distance away and washed into the rift valley. The sediments also include the fossilised remains of dead animals, plants and trees. The time between the floods was long enough for large trees to grow, perhaps at least 100 years, and the floods were catastrophic.

Cliff at Inverloch “The main fossil bearing layer (under the red line) consists of grey sandstone with coal throughout it. The layer is bounded by a layer of mudstone below and massive sandstone above.
Image: Lisa Nink
Source: Museum Victoria

There are many fossilised tree stumps on the shore platform. Some of these trees lie horizontally with their fossilised roots still attached and are believed to have been knocked over by the force of the floods and washed down the river. We also find fossil leaves of ferns, gingkoes and monkey puzzle-like trees that once grew as part of a forest within the rift valley.

Fossil tree trunk A fossil tree trunk. If you look closely you can even see the growth rings.
Image: Lisa Nink
Source: Museum Victoria
 

The coal in the fossil layer is the remains of decomposing plants that once grew in the valley. Fossilised grains of pollen from these plants have also been found and by identifying their species, we can date the sediments surrounding them.

A nearby dyke (a long straight crack in the rocks through which magma from deep below the Earth's crust travels upwards and cools) is made up of basaltic rock, another igneous rock type. The dyke is 99.5 million years old and cuts through the grey sandstone, meaning it formed after the sedimentary rocks had been deposited. 

volcanic dyke at Inverloch Dale Nelson stands upon the basaltic dyke near the Flatrocks site.
Image: Lisa Nink
Source: Museum Victoria
 

We also find minerals at the site, like pyrite and calcite.

Crystals found at dinosaur dig Minerals found at the fossil dig site, shown with objects often found in geologists' pockets, for scale. Left: Pyrite crystals | Right: Calcite crystals
Image: Lisa Nink
Source: Museum Victoria
 

Links:

Dinosaur Dreaming blog

Infosheet: Dinosaur Dreaming - the Inverloch fossil site

Video: Dinosaur Dreaming

Dinosaur Dreaming dig season opens

Author
by Lisa
Publish date
16 February 2012
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Comments (1)

Lisa works in the Public Programs Department at Melbourne Museum but also volunteers in the Palaeontology Department and has been on several fossil digs.

Last weekend hailed the beginning of the annual Dinosaur Dreaming dig season at Inverloch in Victoria. The crew will spend the next three weeks searching for the fossils of animals including dinosaurs, mammals, turtles, freshwater plesiosaurs, fish and pterosaurs that lived on and around the floodplain and in the forests that existed in the area 120 million years ago.

We can only access the dig site while the tide is out far enough to expose the shore platform, and before we can start hunting for fossils we need to prepare the site. First we remove the sand with shovels, which is often a bit of a smelly job due to the bits of rotting seaweed that have washed into the hole (the name we give to the part of the site which is being worked at any given time) with the tide.

Preparing the fossil site dig Left: The crew removes sand, boulders and seaweed from on top of the rock layers. Right: John Wilkins and Dean Wright remove one of many large boulders from the dig site using a boulder extraction contraption John invented and built for us.
Image: Lisa Nink
Source: Museum Victoria
 

Next we use large chisels, crowbars and large drills to remove the overlying layer of sandstone. Once we have access to the fossil layer we can begin searching.

Some of the crew use large chisels and sledgehammers to remove large chunks of the fossil layer and the rest of the crew sit further up on the shore breaking these large rocks into walnut sized pieces in search of fossils.

Breaking rocks to find fossils Left: Travis Park uses a sledgehammer and chisel to remove a large chunk of fossil-bearing rock. Right: Gerry Kool uses a much smaller hammer and chisel to break down chunks of rock in search of fossils.
Image: Lisa Nink
Source: Museum Victoria
 

While the main aim of the dig is to find fossils, there is much more we can learn about the site. Dean Wright, a surveyor, and Doris Seegats-Villiers, a PhD candidate at Monash University, used a Leica Total Station to collect data which will be used to map geological features such as the different rock layers and fault lines. Dean plans to overlay this data onto a 3D map of the site he made last year and this information will assist scientists to better understand the geology of the site.

measuring geology of fossil site Dean Wright and Doris Seegats-Villiers taking data points which Dean will use to create a geologic map of the Flatrocks site.
Image: Lisa Nink
Source: Museum Victoria
 

Some of the interesting bones we have found so far this season:

dinosaur bones found at Inverloch Left: A cross-section through a dinosaur limb bone. Right: A cross-section through a dinosaur toe bone.
Image: Lisa Nink
Source: Museum Victoria
 

Links:

Dinosaur Dreaming blog

Infosheet: Dinosaur Dreaming - the Inverloch fossil site

Video: Dinosaur Dreaming

Happy Darwin Day

Author
by Ursula
Publish date
11 February 2012
Comments
Comments (3)

Ursula Smith works in the natural sciences collections at Museum Victoria. Though a palaeontologist by training she finds all the collections fascinating and swings between excitement at all the cool stuff in them and despair at the lack of time to look at it all.

February 12th is Charles Darwin's birthday, now celebrated at institutions around the world as Darwin Day. Darwin's work is obviously relevant to a lot of the research that goes on at Museum Victoria today, but we also have a direct link with him through some specimens housed in the Palaeontology Department.

Charles Darwin in 1854 Charles Darwin in 1854
Source: Out of copyright, via Wikipedia.
 

Darwin's best-known work is The Origin of Species, and if you had to name the animals he was particularly interested in, you'd probably think finches, or perhaps tortoises. But these are just the tip of the iceberg; before, and after publishing The Origin, Darwin also published prolifically across a breadth of natural history subjects, including geology, zoology, ornithology, entomology and botany. All of this work was vital, both in developing his theory of evolution by natural selection, and in gaining him a wide and interested audience.

One of the lynchpins of Darwin's theory was homology, the sharing of characters due to common descent (meaning that if two species share a feature we assume, until we can show otherwise, that they both inherited it from their common ancestor). Much of Darwin's thinking about homology was developed through his detailed study of the humble barnacle. He published the first full treatment of barnacles in the early 1850s with four monographs on modern and fossil barnacles.

Over 100 years later in the 1960s, the then Curator of Palaeontology at Museum Victoria, Thomas Darragh, noticed that some of the specimen labels in the palaeontology collection had handwritten notes saying "Original figured by Darwin".

Specimen label written by Kranz. Specimen label written by Kranz.
Source: Museum Victoria
 

Going back to Darwin's original descriptions and illustrations, Dr. Darragh confirmed that these specimens matched Darwin's material. For instance, looking at this photo of Scalpellum simplex and the original illustration, it's clear that the illustration is of this specimen – they share the same broken tip even though the figure shows the specimen free of the rock. Similarly, the other specimens are close matches to those in Darwin's monographs.

  Barnacle Scalpellum simplex Darwin 1854, illustration and fossil Left: Extract of plate from Darwin's original monograph. | Right:Fossil barnacle Scalpellum simplex Darwin 1854. Scale bar = 1cm. (NMV P133334).
Image: Charles Darwin | Thomas Watson
Source: Out of copyright | Museum Victoria
 

A little more investigation showed that all of the specimens Dr. Darragh had found had been declared lost by Thomas Henry Withers in the 1930s when he compiled a catalogue of the barnacle material at the Natural History Museum in London (then the Natural History section of the British Museum). So the specimens that had been thought lost for over 30 years were now found, but how had they come to be in Melbourne instead of London?

In 1854 when his work on barnacles was complete, Darwin donated all the material that he had collected himself to the British Museum, where, 80 years later, Withers made his catalogue. However, Darwin also borrowed from other collectors. One of these was John Morris, a mollusc specialist possibly best known for The Catalogue of British Fossils and who went on to become professor of Geology at University College London. When he donated his own collection, Darwin returned Morris' material to him. Morris later sold his collection to the German fossil dealer, August Krantz who, for some reason, discarded all of the original labels and re-wrote them.

In 1863, Frederick McCoy, the first director of Museum Victoria (then known as the National Museum of History and Geology) bought a collection of fossils from Krantz for the museum.

This was just one of many purchases of fossils and minerals that McCoy made from Krantz, but this one happened to include at least part of Morris' collection, including the barnacles that Darwin had worked on. Since nobody was actively working on barnacles, it took 100 years for anyone to realise the importance of these specimens, but since we did the specimens have been housed safely in the museum's type collection accessible for researchers around the world.

Happy Darwin Day!

Links:

Darwin Online Project 

Darwin's barnacle studies (Darwin Online Project)

Invertebrate Palaeontology Collections

Infosheet: How do barnacles cement themselves to rocks?

Whale vs shark

Author
by Ursula
Publish date
7 February 2012
Comments
Comments (1)

Ursula Smith works in the natural sciences collections at Museum Victoria. Though a palaeontologist by training she finds all the collections fascinating and swings between excitement at all the cool stuff in them and despair at the lack of time to look at it all.

This cabinet contains parts of the skeleton of a fossil whale collected at Bells Beach, on the Surf Coast southwest of Melbourne.

collection cabinet Vertebrate Palaeontology Collection storage cabinet full of fossils.
Source: Museum Victoria
 

This story is only indirectly about that whale, but it does start with one of its bones:

Fossilised whale bone. Fossilised whale bone.
Source: Museum Victoria
 

This is a metacarpal – a bone from one of the whale's flippers (forelimbs). Here, it's being held by Dr Erich Fitzgerald, Senior Curator of Vertebrate Palaeontology and Harold Mitchell Fellow at Museum Victoria, which gives you an idea of the size – it's about 7cm long. The equivalent bone in a human hand (the bone that runs between your middle finger and your wrist) is about the same length, though not as chunky.

At the top of the bone, you can see two grooves that make an inverted 'V'. While they might not look particularly impressive, to Erich's eye that chevron shape was an immediate clue to something that's quite rare to find in the fossil record: it's a classic example of the marks left on bone by shark teeth. We know what a modern shark bite looks like from observing modern sharks and their prey, and the marks on this bone look just like the sorts of marks a modern shark bite makes. In the next photo, Erich is re-enacting the way a shark's tooth would make this sort of mark, (though obviously when a shark bites there are many more teeth involved).

Shark tooth and whale bone Erich demonstrates how a shark tooth probably struck the whale bone.
Source: Museum Victoria
 

While it's not absolutely conclusive evidence – this sort of palaeo-behaviour trace fossil rarely is – this, and other marks on other bones from the same specimen, is enough for us to be fairly certain that this whale was bitten by a shark. We also know that this happened very close to the whale's death because the bone shows no sign of healing. This tells us that either the whale was killed by the shark that attacked it or that the shark was scavenging the whale carcass after it died – we can't be sure which but we know that the whale wasn't bitten and then got away.

Even with this uncertainty, though, this is more information than palaeontologists usually have about interactions between animals in the fossil record. Information modern ecologists take for granted, such as who's eating who, is extremely rare to find for fossils. Bite marks like these are one of the few ways palaeontologists have any idea of how food webs may have been constructed way back when. But what's really cool about this particular whale/shark palaeo-interaction, is that rather than just being satisfied with 'this whale was attacked by a shark' we can actually figure out who the culprit was. A lot of work has been done on the geological unit that this specimen was collected from so we know what was sharing the waters with our luckless whale. Of the list of sharks known from the same unit, only one has teeth big enough to have made these marks:

Fossil shark tooth Fossil shark tooth.
Source: Museum Victoria
 

This tooth comes from the shark Carcharocles angustidens, known from relatively abundant fossils around the stretch of coast our whale was collected from. C. angustidens is a close relative of the rather more famous Carcharocles megalodon which has the largest teeth of any known shark, living or extinct (some are over 18cm long!) You can see the sharp little serrations along the edge of the tooth which would have effectively sawed into the bone of its victim, leaving the grooves we see in the whale's bones today.

So we think that somewhere in the Late Oligocene, 24-27 million years ago, in a sea that covered what is now part of Victoria, a shark, Carcharocles angustidens, bit a Mammalodon whale and perhaps even killed it. It's amazing what we can infer from just a few scratches on bone.

Links:

MV Blog: Evolving the biggest mouth in history

Footage of tiger sharks scavenging a whale carcass in Queensland

Footage of sharks eating a blue whale alive

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Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

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