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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Alberta’s famous dinosaur palaeontologist…

The highly acclaimed dinosaur palaeontologist Professor Phil Currie of the University of Alberta recently added the Royal Canadian Geographical Society gold medal to a long list of awards and accomplishments. Alberta Primetime has published a very nice on-line film about Phil Currie called “Alberta’s doctor of dinosaurs”, which I highly recommend.

Phil Currie is one of the world’s leading experts on dinosaurs, especially theropods of the Tyrannosauridae, and has also worked extensively with the origin of birds. He is also married to Eva B. Koppelhus, a dear old palynology-colleague of mine 🙂

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?

Upper Triassic detrital zircon datings support diachronous rise of Dinosaurs

Red beds are common in Upper Triassic terrestrial sedimentary successions worldwide. Having formed in semi-arid to arid environments, these rocks are generally sparse in fossils. This is perhaps mainly because the preservation potential for fossils in such environments is poor, and not necessarily because there were no plants and animals at the time of deposition. 
The Upper Triassic Kågeröd Formation at Bälteberga Gorge, Scania. (Photo: M. Erlström)
On the Colorado Plateau in southwestern U.S.A. the Upper Triassic red bed succession of the Chinle Formation, deposited by river systems and small lakes under an arid climatic regime, contains well preserved fossil plants and vertebrate remains; archeosaurs, dinosaurs as well as the precursors of dinosaurs, the dinosauromorphs (see e.g. Irmis et al., 2007; Nesbitt et al., 2009). However, relative datings of these fossil floras and faunas have been hampered by the fact that they occur within an otherwise relatively fossil-poor terrestrial succession. They have traditionally been assigned a Carnian to early Norian age, based on fossil spores and pollen (Litwin et al., 1991).
 

A detrital zircon from the Upper Triassic of Scania (Photo: S. Lindström)

 
But now Randall Irmis and his colleagues (read the abstract here) present two new radioisotopic datings on detrital zircons that indicates that the Chinle Formation is younger than previously thought, namely between ~218 and ~212 million years old (maximum ages), i.e. mostly or wholly Norian in age.
 
This means that the early dinosaurs of North America are younger than their famous South American counterparts from the Ischigualasto Formation in northwestern Argentina.
 
This suggests that dinosaurs evolved diachronously on either side of the Equator…