Closing in on Jurassic Park

Several years ago, while I was still working at Lund University, one of my colleagues Dr Johan Lindgren came to me one day with a microscope slide and asked me if I could help him check if there was anything in it. The only things we found were very small (ca 10-15 μm) spiny oval things, definitely not something palynological but most likely something organic of some sort.

Johan Lindgren showed me a paper by Mary Schweizer et al. (2007) which depicted small spiny cells from soft-tissue preserved inside bones from three different dinosaurs Tyrannosaurus rex, Triceratops horridus and Brachylophosaurus canadensis.

These cells were believed to be osteocytes, small star-shaped cells that reside inside bones and which can live as long as the organism itself and are capable of bone deposition and resorption.

The small spiny oval things that Johan Lindgren had in his slide definitely looked similar, although they did not come from a dinosaur but from a 70 million year old Mosasaur.  Because this bone came from a marine reptile, a creature that had lived and died in the ocean, Johan Lindgren was determined to rule out that contamination from sea-sediment or other organisms was the source of the small spiny cells, and after years of research he finally published his results in the highly acclaimed open-access journal PLos One: Lindgren et al. 2011: Microscopic evidence of Cretaceous Bone Proteins. The photographic plate below from the Lindgren et al. (2011) paper shows the tiny spiny osteocytes still looking amazing after 70 million years!! 🙂

Fig. 1. from the Lindgren et al. (2011) paper showing the spiny osteocytes in photos A-F.

Fig. 1. from the Lindgren et al. (2011) paper showing the spiny osteocytes in photos A-F.

Research performed on soft-tissue preserved in fossil bones are bringing us closer to the plot of Stephen Spielberg’s 1993 motion picture “Jurassic Park”, after a novel by Michael Crichton. Mary Schweitzer and her colleagues have just published a new paper in the journal Bone: Schweitzer et al. (2013): Molecular analyses of dinosaur osteocytes support the presence of endogenous molecules, in which their data are the first to support preservation of multiple proteins and to present multiple lines of evidence for material consistent with DNA in dinosaurs.

You can read more about this study on: ScienceDaily

However, there is still a long way to go before anyone can genetically modify frog-DNA and recreate Tyrannosaurus rex or any other dinosaurs like they did in “Jurassic Park”.

Jurassic Park logo, borrowed from the official website: http://www.jurassicpark.com/
Check it out!

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Large herbivorous dinosaurs sustained Mesozoic greenhouse climate through flatulence?

In our society today we are very much aware of the effects of greenhouse gases on the climate. Global warming due to anthropogenic pollution has been discussed vigorously over the last decade. We spend enormous amounts of money on research and development of Carbon Capture and Storage, i.e. the possibilities of storing excess carbondioxide underground.

Geologists discuss the causes and effects massive release of carbondioxide or the four times more potent greenhouse gas methane possibly had on the climate and on life on Earth during the end-Permian and end-Triassic mass extinction events.

In a quest to find out what is normal and not normal when it comes to carbondioxide levels in the atmosphere, and the circulation of carbon on Earth, researchers have found out that our domestic cows produce some 50-100 million tonnes methane per year by gases formed in their guts.

Sheep are also environmental bad guys… 😉

Now a team of researchers lead by David Wilkinson have calculated how much methane may have been produced by large herbivorous dinosaurs, the so called sauropods including e.g. Apatosaurus, and their best estimates suggest 520 million tonnes of methane per year. A truly staggering amount as this equals the total combined methane emissions per year from all sources on Earth, i.e. from all animals and all human activities. 

     Sauropods probably had big guts containing lots of methane producing microbes!

The mean global temperature during the Mesozoic is estimated to have been 10 degrees Celsius warmer than today. Interestingly the Jurassic and Cretaceous periods are in general considered to have been periods of high diversity and productivity, both at sea and on land, despite the high levels of carbondioxide in the atmosphere.

So how come we fear carbondioxide and methane emissions today?

The key issue is probably time. Our planet; its interacting animals and plants, minerals and rocks, needs time to adapt to environmental changes. Fast injection of huge amounts of greenhouse gases to the atmosphere, whether from massive volcanism or from anthropogenic emissions, can shift climatic zones and cause major disruptions in ecosystems.

Perhaps the methane farts from the herbivorous dinosaur populations only sustained the greenhouse climate that was initiated at the end-Triassic?

Perhaps they didn’t really make things worse…just kept things normal?

T-rex relatives had chicken-down…

A team of researchers in China have recovered fossil remains of downy feathers on two juveniles and one adult of the dinosaur Yutyrannus hauli, a distant and much smaller relative of the more famous carnivourous dinosaur Tyrannosaurus rex.

Yutyrannus hauli lived in China during the Cretacous, ca 125 million years ago. An adult Yutyrannus is estimated to have weighed 1.400 kilograms and to have been ca 9 meters long. The feathers found on the three fossil specimens are between 15-20 cm in length. The fact that the fossil feathers were found in patched on different parts of the three specimens indicate that Yutyrannus was in fact completely covered by these downy proto-feathers. The feathers are thought to have acted as insolation to retain body heat, but other theories includes helping to keep the eggs in the nest warm, attract mates or they may have acted as camouflage.

Tyrannosaurus?

This of course raises the question whether T-rex was also feathered or not? Some think it is a ridiculous thought.

I think anyone who’s ever come across an angry goose or swan knows how scary big birds can be. Just imagine a downy 4.5 ton T-rex… 

Happy Easter! 🙂

The less spectacular period boundary of the Mesozoic…

I guess most people interested in geology and the history of life on Earth have heard about the dramatic period boundaries of the Mesozoic.

The most well known is of course the upper boundary of the Mesozoic, the Cretaceous-Paleogene boundary which marks the demise of the dinosaurs ca 65 million years ago. This boundary is marked not only by a catastrophic extraterrestrial impact, but is also contemporaneous to massive volcanism (Deccan Traps in India) and subsequent climatic and environmental  changes of these events.

Almost equally famous and marked by an even bigger mass extinction is the lower boundary of the Mesozoic, the Permian-Triassic boundary ca 251 million years ago, associated with the end-Permian mass extinction event when ca 95% of all life died out. The end-Permian event is linked to massive volcanism in Siberia and the longterm climatic and environmental consequences where so severe that the major part of the Triassic is characterised by a harsh arid hothouse climate.

Some have probably also heard of the Triassic-Jurassic boundary, ca 201 million years ago, also associated with a major mass extinction event linked to the perhaps largest large igneous province known, the Central Atlantic Magmatic Province – massive volcanism during the initial opening of the Central Atlantic – with severe climatic and environmental consequences.

Am I repeating myself? 😉

But how many have heard of the Jurassic-Cretaceous boundary ca 145 million years ago?

This less well-known period boundary is also marked by major climatic changes. At least on the northern Hemisphere. Palynological, sedimentological and geochemical studies bear witness of climatic change from predominantly arid to semi arid conditions in the latest Jurassic to more amicable humid conditions in the earliest Cretaceous of NW Europe (see e.g. our paper Lindström and Erlström, 2011 for references).

So far, this less spectacular period boundary has not been linked to any major volcanic events or extra terrestrial impacts. And now Valentin Fischer and his colleagues have published a study in PLoS ONE (read paper here) about one specific ischtyosaur that survived the less famous Jurassic-Cretaceous (J/K) mass extinction and in fact their study suggests that the J/K event hardly affected ischtyosaurs at all 😀