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:
Check it out!

Triassic-Jurassic fossils from Scania: (I) dinosaur tracks

The Triassic-Jurassic transition of Scania has been one of my favourite research subjects since I was a student back in the late 1980ies. Back then I once again came in touch with the sedimentary rock escarpments of my hometown when working on two small research projects. I got to revisit slopes and outcrops where I used to play as a child, weathered but beautiful and home to bats and various spiders and various insects.  Far from a safe playground but as kids, we loved the “wild” sanctuary within the city. Maybe that is where I first fell in love with geology?

If I had known back then when I was a kid, what creatures had actually roamed my “hometown area” during the latest Triassic, Rhaetian, I would probably have been even more fascinated by those rocks. But back then, fossils and dinosaurs was not common knowledge.

Eventhough the Rhaetian and Hettangian (earliest Jurassic) sedimentary rocks of Scania have been extensively quarried for coals and clays during many centuries, no dinosaur fossil bones have ever been recovered. But dinosaur trace fossils of the ichnogenus Grallator have been recovered at several localities, see e.g. Gierlinski and Ahlberg 1994. In this paper the authors describe two different Grallator ichnospecies from various localities in NW Scania. The larger Grallator sp. cf. giganteus, which measures 32 cm in length, and the smaller 15-26 cm long Grallator soltykovensis.

Grallator soltykovensis (LO5463t) from the uppermost Rhaetian at southern Vallåkra. Photograph of original housed at the Department of Geology, Lund University. Drawing of the same specimen from Gierlinski and Ahlberg (1994).

 To date, the Scanian Grallator-trackmakers are unidentified. The Scanian Grallator tracks were defintely made by biped dinosaurs and display between three and four digits, three pointed forward and one backwards. The presence of many tracks of various size (between 15 and 35 cm in length) at southern Vallåkra (no longer exposed outcrop) suggest they were left by a herd, or pack if they were carnivors, of juvenile and adult individuals (Gierlinski and Ahlberg, 1994). My own research on dating the Triassic-Jurassic boundary (by palynology) sediments clearly shows that the tracks were all made during the Rhaetian. Hence, we do not know if the dinosaur-taxa that left these tracks survived the end-Triassic mass extinction event. 

 Hopefully one day someone will recover the fossil bones of the dinosaurs that left these amazing tracks and roamed the latest Triassic Scanian landscape.

Time to colour the fossil record…

Since the dawn of palaeontology, researchers and artists have strived to reconstruct ancient extinct life forms. By combining the fossil remains with knowledge of anatomy or botany pioneers like Henry de la Beche (1796-1855) and Charles R. Knight (1874-1953)  envisioned the forms and colours of prehistoric life on Earth (read more about palaeoartists here) and brought us the first ideas on what e.g. dinosaurs may have looked like.

Recently, palaeontological research have broken new ground by identifying melanin – a black, brown or red colour pigment that occurs in both animals and plants – in fossils. Since Jakob Vinther and colleagues published their paper “Plumage Color Patterns of an Extinct Dinosaur” more reports of preserved melanin-residues in fossils have surfaced. Two of the latest deal with: pigment in a 50 million year old fossil fish eye (Lindgren et al. 2012) and in a 160 million year old fossil squid ink sac (Glass et al. 2012).

The fossil record will never be the same 😉

However, we will always need reconstructions and paintings depicting the past. Check out this wonderful webpage with beautiful palaeo-scenery: Evolutionary routes

Birds have baby-dinosaur-skulls!

Pedomorphosis is an evolutionary process through which descendants end up looking like the juveniles of their ancestors. There are many known examples of this in the fossil record, e.g. amongst trilobites and amphibians.

Now, a study by Bhullar and colleagues in Nature show that birds skulls are morphologically similar to baby dinosaur skulls, indicating that birds are not only descendants of dinosaurs, but they have retained a juvenile morphology. One of the traits typical of baby dinosaurs is a large eye socket, and this is also typical for adult birds. While the morphology of baby dinosaur skulls were very different from those of their adults, baby birds have skulls that are virtually similar to adult birds. This has allowed birds to take a faster and more direct route to adulthood.

You can read more and view pictures of the skulls on Dinosaur tracking.

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.


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 😀