Biology Ancient Australia (Extinct Megafauna, Dinosaurs etc)

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The placoderm and Devonian fish thing continues.

materpiscis.jpg

From the Gogo Formation in the Kimberley region of Western Australia we have one of the most amazing late Devonian fossils in the world, a single specimen of Materpiscis attenboroughi , the genus name means mother fish and the species name comes from Sir David. Just under a foot long, it has a sort of cartoon appearance. What is unique is there is an unborn embryo present inside the mother, including preservation of a mineralised umbilical cord and placenta.

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While it was a bad day for mother & daughter, it's an incredible find for us. At 380 million years old, it is the oldest known vertebrate to give birth to live young. This magazine article talks more about it - Your Weekly Attenborough: Materpiscis attenboroughi | Discover Magazine

There were some big beasties during the Devonian, this graphic depicts some very large and nasty looking Placoderms and sea scorpions.

Sz-devonianSM.jpg
 
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Continuing on the placoderm theme, an interesting 'placoderm, from NSW was brindabellapis, the 'duck billed placoderm'. New information on Brindabellaspis stensioi Young, 1980, highlights morphological disparity in Early Devonian placoderms | Royal Society Open Science (royalsocietypublishing.org)

platypus-fish-life-reconstruction-courtesy-jason-art-shenzhen.jpg ​

A just recent paper has used scan data to show the inner ear of brindabellaspis looks more like a modern vertebrate than other placoderms Endocast and Bony Labyrinth of a Devonian “Placoderm” Challenges Stem Gnathostome Phylogeny: Current Biology (cell.com). It has sort of thrown the relationships between these early vertebrates up in the air, although it must be said it's pretty uncertain territory. If true, it may be we are all placoderms or rather their descendants. I certainly have met enough boneheads in my life to convince me it's possible.
 
Biggest Australian dino - Australotitan cooperensis grew up to 30 metres long and up to six metres high at the hip. Titanosaurs were the last of the big sauropods to evolve and I don't think they have been identified here before. - Largest dinosaur discovered in Australia a true world heavyweight (theage.com.au)

If you look at this one way, this could be from Land of Giants and those are wee little people, very pleased with their chicken bone.

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Monk seals are warm weather, true seals, only found now in a couple of locations worldwide and at very high risk of extinction. Despite the limited range nowadays, monk seals where more widespread in the past. Bones have been found at Beaumaris and other sites in Australasia. This recent article talks about it - The most endangered seals in the world once called Australia home (theconversation.com)

The illustration below is by my friend, Peter Trusler showing 2 extinct species with modern day relos. They have a fairly broad nose compared to most other seals, which is hinted at in the illustration. The Caribbean monk seal was hunted to extinction in the 20th century.

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CD Xbow said:
Monk seals are warm weather, true seals, only found now in a couple of locations worldwide and at very high risk of extinction. Despite the limited range nowadays, monk seals where more widespread in the past. Bones have been found at Beaumaris and other sites in Australasia. This recent article talks about it - The most endangered seals in the world once called Australia home (theconversation.com)

The illustration below is by my friend, Peter Trusler showing 2 extinct species with modern day relos. They have a fairly broad nose compared to most other seals, which is hinted at in the illustration. The Caribbean monk seal was hunted to extinction in the 20th century.

file-20210611-25-uo22nj.jpg
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Interesting bit of knowledge and beautiful illustration. Thanks for sharing everyone! I enjoy reading this thread :)
 
My friend Peter (Trusler) has a new series of stamps coming out, another Dino set. The Mint really likes Dinos, I think this is his 3rd series of Dino stamps - James Gurney talks about Peters earlier stamps - Peter Trusler and the Dead Wombat. The philatelists will be able to collect them later in the year. The original painting is surprisingly small, probably only a couple of foot wide but insanely detailed. He modelled a life size half head of Minmi, so he could get it right in the painting. it gave me the shits to see half a head, so I did the other side. I plan to finish it one day and make a proper work out of it, it's pictured below in current 80% finished state.

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Also pictured is Peter's new book, Thrice Told. I know I must be sounding much like Peter's publicist, but it's worth a look. It's in part coffee table book with lot's of pictures of mainly his non paleo work. There are a couple of Dinos' but that's all. What makes it unusual is that it's written with his therapists, so it's a psychological work as well. I expect it will be available later in the year through Amazon and you may find it in Readings.
 
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Museum of Victoria has a new exhibit of an almost complete Triceratops Horridus. It is described as “the most complete, exquisitely preserved Triceratops fossil found in the 130-odd years since the species was first named.” The Museum paid almost $3 million for Horridus which it will be unveiling it to the public on March 12. I am told the bones are exquisitely detailed. Tail vertebrae illustrated below.

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See https://museumsvictoria.com.au/melbournemuseum/whats-on/triceratops-fate-of-the-dinosaurs/
 
www.abc.net.au

A 'little baby' the size of an elephant: Meet Ollie, Australia's smallest sauropod dinosaur

After more than a decade of painstaking research, a plant-eating dinosaur found in outback Queensland has been officially dubbed the smallest sauropod in Australia.
www.abc.net.au www.abc.net.au

Fossils unearthed in outback Queensland more than a decade ago have been officially identified as Australia's smallest sauropod... The plant-eating dinosaur is estimated to have measured about 11 metres in length and weighed 4.2 tonnes— roughly the size of an adult elephant — at the time of its death
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Werewolf said:
www.abc.net.au

A 'little baby' the size of an elephant: Meet Ollie, Australia's smallest sauropod dinosaur

After more than a decade of painstaking research, a plant-eating dinosaur found in outback Queensland has been officially dubbed the smallest sauropod in Australia.
www.abc.net.au www.abc.net.au
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So Little Foot was an Aussie! Just have to find Cera, Ducky and Spike.

The 'Demon Duck of Doom' is getting a run in ArsTechnica of all places. Mysterious ancient giant eggs Down Under laid by Aussie “demon ducks of doom” They have used Peters picture of it being chased by Megalania as the main graphic and actually attribute it correctly. There has always been controversy if climate change or the impact of the arrival of humans were the main causes of the birds extinction. Paleo's have found eggs from the correct time and place that appeared to have been cooked but there were questions who the eggs belonged to. Summary from the paper below;

"The controversy over the taxonomic identity of the eggs exploited by Australia’s first people around 50,000 y ago is resolved. The birds that laid these eggs are extinct, and distinguishing between two main candidates, a giant flightless “mihirung” Genyornis and a large megapode Progura, had proven impossible using morphological and geochemical methods. Ancient DNA sequencing remains inconclusive because of the age and burial temperature of the eggshell. In contrast, ancient protein sequences recovered from the eggshell enabled estimation of the evolutionary affinity between the egg and a range of extant taxa. The eggs are those of a Galloanseres (a group that includes extinct Dromornithidae, as well as extant landfowl and waterfowl), Genyornis, and not of the megapode (Megapodiidae, crown Galliformes).'

Original paper is here https://www.pnas.org/doi/full/10.1073/pnas.2109326119.
 

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Tom Rich (probably our greatest paleo) and Tim Flannery (probably out greatest biologist) et al, have published a paper suggesting the origins of mammals occurred during the Jurassic, in the southern hemisphere, probably starting in South America. This is based on 'tribosphenic molars' that have been found in odd places. Tom identified the first one that was found at Inverloch more than 20 years ago, and I am told this was a little speculative at the time. Since then, more have turned up all over what was Gondwana. I discussed some of these in earlier posts. Fairfax have an article about it
‘Remarkable Australian story’: Tiny Jurassic teeth rewrite history of mammals

The original paper is here Origin of Mammals - Google Drive

The drawings of the teeth and jaws were done by my friend Peter (Trusler). I watched him draw some of these. Talk about OCD, the teeth are about the size of grains of rice and some of the jaws are only a couple of centrimetres. See image below.

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Clever folks have modelled the movement of the first humans into Sahul (=the super continent of Oz, PNG and associated islands) during the late Pleistocene. There is a link to the original Nature paper in the article if you wish to torture yourself.

www.sciencealert.com

Scientists Reveal How Humans First Populated The Ancient Megacontinent of Sahul

Between 75,000 and 50,000 years ago, humans began to make their way across the megacontinent of Sahul, a landmass that connected what is now Australia, Tasmania, New Guinea, and the Aru Islands.
www.sciencealert.com www.sciencealert.com

Their modelling suggests migration likely began through Timor, then later through western parts of New Guinea. Rapid expansion would then have happened southward toward the Great Australian Bight and northward to New Guinea. Expansion followed down the east coast southward, with Tasmania occupation occurring between 9,000 and 10,000 years following the initial arrival in Sahul. They modelled arrival dates of 75,000 years and 50,000 years respectively, the later to my mind is way too late. Their findings pretty much aligns with archeological and genetic evidence.
 
CD Xbow said:
Clever folks have modelled the movement of the first humans into Sahul (=the super continent of Oz, PNG and associated islands) during the late Pleistocene. There is a link to the original Nature paper in the article if you wish to torture yourself.

www.sciencealert.com

Scientists Reveal How Humans First Populated The Ancient Megacontinent of Sahul

Between 75,000 and 50,000 years ago, humans began to make their way across the megacontinent of Sahul, a landmass that connected what is now Australia, Tasmania, New Guinea, and the Aru Islands.
www.sciencealert.com www.sciencealert.com

Their modelling suggests migration likely began through Timor, then later through western parts of New Guinea. Rapid expansion would then have happened southward toward the Great Australian Bight and northward to New Guinea. Expansion followed down the east coast southward, with Tasmania occupation occurring between 9,000 and 10,000 years following the initial arrival in Sahul. They modelled arrival dates of 75,000 years and 50,000 years respectively, the later to my mind is way too late. Their findings pretty much aligns with archeological and genetic evidence.
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Did they model numbers of arrivals?

I have heard figures as low as 120 being the absolute minimum required
 
GreyCrow said:
Did they model numbers of arrivals?

I have heard figures as low as 120 being the absolute minimum required
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No, no numbers. The main interest was how the patterns of dispersal occurred over time & space.

I have seen many figures given based of genetic interpretation of data that range from hundreds to thousands. This article claims about 3000 original aboriginal arrivals based on anthropologic data, but it requires a lot of assumptions for the method to be accurate. I suspect the number is larger rather than smaller. If it was a hundred or so I would expect a very high incidence of obvious genetic diseases related to a very limited gene pool, which isn't the case with aboriginals as far as I know.

www.science.org

Who Were the First Australians, and How Many Were There?

Study suggests continent was colonized by more people than originally suspected
www.science.org www.science.org

The paper states their data suggests aboriginal population accelerated 12,000 years ago, this raises a red flag to me because that is after the last glacial maximum, when many coastal areas would have become flooded. So perhaps the apparent acceleration is because many older sites have been lost under the waves.
 
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A virtually complete Cooyoo australis has been found in QLD, this specimen was of such fidelity it contained the remains of 2 fish in its stomach. 100 million years ago these guys were middle level predators in the Eromanga sea and did a side gig in scaring children at parties. Read about it here:

www.abc.net.au

Tourists unearth 100 million-year-old marine predator in western Queensland

Tourists discover one of the most complete fish fossils in Australia. Here's what was found in its belly.
www.abc.net.au www.abc.net.au
 
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A new paper from Nature has the folks from ANU looking for and finding sterol precursors in rocks from 1.6 billion years ago. All animals, plants, fungi, and many unicellular organisms are eukaryotes. It's one of the 3 'kingdoms' in biology, the others are the two groups of prokaryotes, the Bacteria and the Archaea. Eukaryotes rely on fat-like compounds called sterols, such as cholesterol, to build cell membranes. Because sterols are found throughout the eukaryotic family tree, they are thought to have been present in the last common ancestor of all modern eukaryotes and have been considered a biomarker for eukaryotes in ancient rocks. The earliest (chemo) fossil record of modern sterols is from about 800 mya. However, there is a large discrepancy between genetic evidence, which suggests the Eukaryotes evolved between 1.2 to 1.8 billion years ago. It has been a bit of a mystery. This paper suggests that early eukaryotes may not have used 'modern' sterols but may have used simpler precursors, thus explaining the discrepancy. The lay persons article is here:

www.nature.com

A ‘lost world’ of early microbes thrived one billion years ago

Fat-like compounds in ancient rocks point to a vast array of previously unknown microorganisms that once dominated complex life on Earth.
www.nature.com www.nature.com

Copy of the abstract:

Eukaryotic life appears to have flourished surprisingly late in the history of our planet. This view is based on the low diversity of diagnostic eukaryotic fossils in marine sediments of mid-Proterozoic age (around 1,600 to 800 million years ago) and an absence of steranes, the molecular fossils of eukaryotic membrane sterols1,2. This scarcity of eukaryotic remains is difficult to reconcile with molecular clocks that suggest that the last eukaryotic common ancestor (LECA) had already emerged between around 1,200 and more than 1,800 million years ago. LECA, in turn, must have been preceded by stem-group eukaryotic forms by several hundred million years3. Here we report the discovery of abundant protosteroids in sedimentary rocks of mid-Proterozoic age. These primordial compounds had previously remained unnoticed because their structures represent early intermediates of the modern sterol biosynthetic pathway, as predicted by Konrad Bloch4. The protosteroids reveal an ecologically prominent ‘protosterol biota’ that was widespread and abundant in aquatic environments from at least 1,640 to around 800 million years ago and that probably comprised ancient protosterol-producing bacteria and deep-branching stem-group eukaryotes. Modern eukaryotes started to appear in the Tonian period (1,000 to 720 million years ago), fuelled by the proliferation of red algae (rhodophytes) by around 800 million years ago. This ‘Tonian transformation’ emerges as one of the most profound ecological turning points in the Earth’s history.
 
Interesting piece about Pademelons, not extinct but very much alive. They seem to be the featured road kill I saw on a recent trip to Tassie. They are extinct in Vic. Unbelievably cute pictures.

www.abc.net.au

Preyed upon and often mistaken for another species — meet the pademelon

How the pademelon often tricks the world into thinking it is the extinct thylacine, and seven other wild pademelon facts.
www.abc.net.au www.abc.net.au


Some of the little fellows climb trees, which provides an analog to how tree kangaroo evolved. A typical kangaroo has got to be one of the worst body plans to ever climb trees. Yet they did.
 
The giant salamander as one article calls it, Arenaerpeton supinatus. This 1.5m temnospondyl amphibian once traversed the freshwater streams of the Sydney basin 240 million years ago. Found by Mihail Mihailidis, in a sandstone slab, which he had acquired nearly three decades ago for his garden. He donated it to the Australian Museum in 1997, the impressive fossil has puzzled scientists for almost 30 years. Recently the 'ring of truth' (CT Scan) proved it to be a temnospondyl amphibian, a group of large crocodile like amphibians that became extinct by the Cretaceous. Australia has a more famous & better named one, Koolasuchus, one of the last temnospondyls. Note temnospondyls are not thought to be direct ancestors of modern amphibians, most believe it is a clade that is extinct.

Scientists name new species of giant amphibian found in retaining wall


See more:

neoskosmos.com

240 million-year-old fossil unearthed by Mihail Mihailidis rewrites history of Triassic Amphibians

A stunning fossil unearthed by a retired chicken farmer has been recognised by experts as a previously unknown species of amphibian from the Triassic period, which roamed the freshwater streams of the Sydney basin 240 million years ago.
neoskosmos.com neoskosmos.com

phys.org

Scientists solve Australian chicken farmer's fossil mystery

A mystery fossil accidentally unearthed by an Australian chicken farmer in the 1990s has finally been identified as a stout amphibian with tusks and "gnarly teeth", scientists said Wednesday.
phys.org phys.org
 
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