New Research Suggests Origins of Flowering Plants as far back as the Middle Triassic

Angiosperms (flowering plants) may have originated more than 100 million years earlier than previously thought according to new research published in the academic journal “Frontiers in Plant Science”.  A team of researchers from the University of Zurich (Switzerland) in collaboration with Geological Consulting & Services of Ober-Ramstadt, (Germany) have discovered microscopic evidence that suggests that flowering plants existed approximately 243 million years ago.  Cores taken from rock strata dating from the Middle Triassic in northern Switzerland have revealed evidence of at least six types of angiosperm pollen, much of which bears a striking resemblance to fossil pollen associated with Lower Cretaceous deposits.

Angiosperms

It had been thought that the angiosperms evolved in the Early Cretaceous, it had even been suggested that the grazing habits of ornithopod and sauropod dinosaurs may have led to pressure on plant populations which resulted in the evolution of the flowering plants – the last of the great plant groups to evolve and one that has grown to encompass over 250,000 species today.  Much of our modern world’s vegetation is characterised by flowering plants and most of our food crops are angiosperms, however, their origins and exactly when angiosperms first appeared has been the subject of a lot of debate.

They probably evolved from derived pteridosperms (seed ferns) but there is a lack of clear, unambiguous fossil evidence to confirm this.  Also, when they first evolved is not clear either, delicate plants do not fossilise well, but the tough pollen grains can be preserved and it is evidence of Triassic pollen grains that has pushed back the potential origins of flowering plants by 100 million years.

New Study Suggests that Scientists May Have to Change their Views on Triassic Flora

A trio of Placerias models. The Placerias replica is great for creating Triassic dioramas.

Picture credit: Everything Dinosaur

The models shown in the image are Placerias figures.  To view the range of Triassic prehistoric animal models in stock at Everything Dinosaur: CollectA Prehistoric Life Figures and Replicas.

Pollen Grain Fossils

Pollen grains are easily dispersed over wide areas due to their relatively small size and the high numbers produced.  They can be found in various depositional environments (marine, coastal, and terrestrial).  For this reason records of fossil pollen are most complete if compared to other plant organs such as seeds or leaves which are considerably more fragile and have a much lower fossilisation potential. Generally accepted first records of angiosperm pollen are mentioned from the early part of the Early Cretaceous (Valanginian—early Hauterivian), corresponding to an age range of approximately 139–133 million years ago (Early Cretaceous).   However, within this interval, pollen fossils are extremely rare and poorly documented.

Most microscopic studies of flora from Lower Cretaceous sediments lack any signs of fossil pollen at all.  However, fossilised grains of pollen become more common in younger Cretaceous rocks and it was because of this data it had been thought that flowering plants evolved in the Early Cretaceous and then rapidly diversified over the next twenty million years or so to establish this group as the dominant terrestrial flora over much of the planet.

A High Resolution, Computer Generated Image of the Triassic Pollen Grains

Evidence of pollen grains from the Middle Triassic.

Picture credit: Peter Hochuli/Susanne Feist-Burkhardt

The scale bar in the picture above measures ten micrometres

A High Fossil Preservation Potential

All angiosperms produce pollen, the male part in reproduction is encased in the tough, protective pollen grain and these tiny grains can be studied using microscopy and other techniques as they do tend to have a high preservation potential.

Professor Peter Hochuli of the University of Zurich and his team used a technique known as confocal laser scanning microscopy to analyse rock samples dating from the Anisian epoch of the Middle Triassic.  The research produced three-dimensional, highly detailed images of the outer, protective elements of fossilised pollen grains.  Six distinct types of fossilised flowering plant-like pollen was identified, potentially changing the impression palaeontologists had of Triassic flora which formerly had been thought to consist of ferns, conifers, cycads, bennettitaleans, caytonialeans and other types of seed-plant. Intriguingly, the microscopic pollen fossils from the Mid Triassic strata looks very similar to the pollen fossils recovered from Lower Cretaceous deposits.

Professor Hochuli stated:

“With a few differences…the pollen from the Middle Triassic look exactly the same as the angiosperm pollen from the Early Cretaceous.”

The research team, which includes Dr Susanne Feist-Burkhardt, suggest that these Triassic samples when compared to the oldest examples of Cretaceous pollen suggest an affinity to a basal group of angiosperms.  Previous studies of Middle Triassic strata from the Barents Sea area, which Professor Hochuli worked on, may also have revealed microscopic pollen-like structures.  This has led to scientists to conclude that flowering plants may have their origins either earlier than the Middle Triassic, perhaps basal forms existed in the Palaeozoic.

What is surprising, is that as far as we at Everything Dinosaur are aware, no evidence of pollen has been found in studies of strata deposited in the Jurassic.  There is now a hefty 100 million year gap between these Triassic aged findings and evidence of pollen being found in Lower Cretaceous aged rocks.  Professor Hochuli has proposed an explanation for this anomaly.  He suggests since scientists such as palaeobotanists did not expect to find pollen in Jurassic samples, they simply did not look for it.

He commented:

“I think part of it [the lack of pollen fossils being found in deposits formed between the Middle Triassic and the Lower Cretaceous] is a gap in the observation, one finds what is already known.  Without my experience from the Barents Sea, I think I would have missed the few tiny grain”

Only a Small Proportion of the Middle Triassic Flora

The pollen grains make up a very small proportion of the overall flora recorded in the Middle Triassic strata, seed ferns, conifers and cycads were very much the dominant terrestrial plant life, but flowering plants had a foot hold which suggests that they may have originated even further back in time.  The research team aim to study other European deposits but those that date from the Early Triassic and the Late Permian in a bid to discover evidence of the first types of flowering plants.

This throws up the interesting possibility that the Permian extinction event may have played a role in altering the mix of flora on our planet.  The Permian period ended with a mass extinction event that wiped out seventy percent of terrestrial species, the void left in ecosystems could have been the spark required to promote the evolution of new types of plant such as the angiosperms.

Aspiration Fossil to be Sold in Texas

A rare fossil preserving an ancient amphibian whose eyes were bigger than its stomach is being auctioned by Heritage Auctions in Dallas, Texas next month.  The sale, part of a special science and nature themed auction is to take place on 19th and 20th October.  The reserve on this particular lot, one that shows a seventy centimetre long amphibian apparently having choked as it attempted so swallow a smaller amphibian is set at $75,000 USD, but with the current interest in fossils, the final price to be paid for this exceptionally preserved evidence of feeding behaviour in a Permian amphibian will probably be much higher.

Rare Amphibian Fossil

The fossil originated in Germany, where laws prevent the collection of such specimens, but this particular fossil was excavated and sold prior to the legislation being in place.  The fossil is currently part of a private collection in San Francisco, but when it is auctioned next month, anyone with a spare £200,000 USD or so can purchase it.

Early Permian Fossil

The specimen dates from the Cisuralian epoch of the Permian (Early Permian), it is approximately 300 million years old and it reveals the last moments of a carnivorous, sub-adult Sclerocephalus haeuseri which may have bitten a smaller amphibian in half (presumed to be a specimen of Cherlyderpeton latirostris or possibly a juvenile S. haeuseri).  The exact identity of the victim is not clear, only the rear half is visible, the rest including that diagnostic, all important skull is inside the remains of the larger amphibian.  Apparently, the sub-adult S. haeuseri was asphyxiated as it tried to cope with its large meal, after all its victim was nearly thirty centimetres long.

Aspiration Specimens

Fossils of a predator choking on its prey are known as aspiration specimens.  They are exceptionally rare in the fossil record, although, Everything Dinosaur is aware of a number of aspiration fossils, most of which feature fish of one sort or another.  A famous example of an aspiration fossil shows a four metre long, Late Cretaceous predatory fish  called Xiphactinus that perished with a two-metre-long, ichthyodectid fish inside its stomach.

The Famous “Greedy Xiphactinus” Fossil Specimen

A fossil fish within a fish.

Picture credit: Sternberg Museum of Natural History

The piece also features a fossil fish, possibly Paramblypterus gelberti which can be seen in the bottom right of the slab in the photographs circulated by the auction house.

A spokesperson from Everything Dinosaur commented:

“This is a truly remarkable and very beautiful fossil specimen.  Aspiration fossils, certainly those featuring tetrapods are extremely rare.  If a public body is unable to purchase this fossil, perhaps the private consortium or wealthy individual who secures this lot will allow it to be made available for further study and analysis – let’s hope so.”

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Evidence of an Extinct Ecosystem Revealed

A team of researchers from the University of Alaska Museum of the North have found a number of major new sites which show evidence of Late Cretaceous dinosaur fossils, not too far from the Arctic Circle.  The research team explored the banks and rocky beaches of the Yukon and Tanana rivers and the expedition returned with over 900 kilogrammes of dinosaur trace fossil specimens.  The fossils represent extensive dinosaur tracks and prints.

Dinosaur Tracks

Commentators have stated that the University of Alaska Museum of the North researchers have found major new sites for dinosaur fossils in Alaska.

Earth Sciences Curator Pat Druckenmiller, a member of the expedition team commented:

“There aren’t many places left in the world where palaeontologists can just go out and find thousands of dinosaur footprints”.

In the high summer (July) with the long days of daylight, the research team set off at the start of a 800 kilometre journey, one that would take them down the Tanana and Yukon rivers and also back in time to the Cretaceous a time when, according to the trace fossils, a large number of different dinosaur species roamed these northern latitudes.

Operations Manager at the Museum, Kevin May stated:

“Based on what we know about the geology along the Yukon River, the rocks exposed downriver from Ruby [a small town 400 kilometres west of Fairbanks] suggested they might be a good place to find dinosaurs”.

Ornithopod and Theropod Tracks

Footprints of both plant-eating dinosaurs (ornithopods) and meat-eating dinosaurs (theropods) were discovered indicating that this part of the Late Cretaceous world supported a rich and diverse ecosystem.  Many different types of prehistoric animal footprint have been recovered from the nearby Denali Park (Lower Cantwell Formation), including those of a giant prehistoric bird that may have stood over 1.5 metres tall.

In fact, the nearby Denali Park is famous for its extensive bird fossil trackways, it seems that birds were also abundant and shared this Late Cretaceous habitat with the dinosaurs.  Intriguingly, the newly discovered dinosaur footprints from the Yukon area are probably 25-30 million years older than the Denali fossils, still Late Cretaceous but indicating a rich and diverse ecosystem flourishing in this part of the world for many millions of years.

Preserved Dinosaur Footprints Found Along the Shore

Picture credit: Pat Druckenmiller

The picture above shows the typical shoreline landscape with large boulders littering the shoreline that have been eroded out of the surrounding strata. The boulder in the foreground shows a positive footprint fossil.

Yukon River Dinosaur Footprints

A Positive Dinosaur Footprint – Ceratopsian Hind Foot?

Picture credit: Pat Druckenmiller with highlighting by Everything Dinosaur

The picture above shows a close up of the dinosaur footprint, although team members at Everything Dinosaur have only this photograph to study and there is no defined scale, it has been suggested that this trace fossil may have been made by the foot of a ceratopsian (horned dinosaur).

Natural Casts

Pat Druckenmiller explained that one of the reasons the Yukon River dinosaur tracks may have gone undiscovered for so long is due to their method of preservation, they are “natural casts” formed when sand filled in the actual footprint after the dinosaur stepped in soft mud. The footprints are not “sunken impressions”, as we refer to such tracks at Everything Dinosaur, rather, they are “raised positive impressions”, that actually stick out and stand proud of the surrounding matrix. A spokesperson for the Alaskan based team stated that the prints “stick out from the rock and sometimes look like blobs with toes.”

The fossil finds are significant as they hint at an extensive dinosaur rich ecosystem that predates those fossils found from the Lower Cantwell Formation of Denali. The University of Alaska Museum of the North are keen to work with local native communities to help co-ordinate future expeditions to the area, perhaps looking for body fossils of dinosaurs so that new genera of Dinosauria may be identified. The dedicated dinosaur footprint spotters included, Jørn Hurum, from the University of Oslo Natural History Museum, UAMN Earth Sciences Collection Manager Julie Rousseau, and University of Alaska (Fairbanks) students Meghan Shay, Katherine Anderson, and Meg O’Connor.

Some of the Expedition Members with their Finds

Picture credit: Kevin May

A Rich and Diverse Dinosaur Fauna

The Head of Production at the Museum Roger Topp, has produced a film of the team’s exploits and the University of Alaska Museum of the North is planning to exhibit their finds in the summer of 2015.

Commenting on the fossil footprint discoveries, a spokesperson from Everything Dinosaur said:

“From the preliminary studies that have been made, these fossilised footprints indicate a rich Dinosauria fauna, with herbivorous ceratopsians and duck-billed dinosaurs dominating the mega fauna. These animals may have migrated to high latitudes to take advantage of food resources during the long periods of prolonged daylight. Predators such as tyrannosaurs may well have followed these herds north and south, picking off the sick and the old.”

A Close Up of an Ornithopod Footprint

Picture credit: Pat Druckenmiller

Researchers Conclude that “Jurassic Park Scenario” Not Likely

The title of the next instalment of the “Jurassic Park” movie franchise may have just been announced (Jurassic World), but for one group of Manchester University academics it is finally time to pour cold water on the idea that dinosaurs could be cloned from DNA recovered from blood-sucking insects that had been found in amber.  Research carried in the early 1990s suggested that minute amounts of DNA could be recovered from insects that had been preserved trapped in tree resin (amber).

However, new research published in the online journal “Public Library of Science – Biology”, which used the very latest DNA recovery techniques, casts doubt on the ability to extract DNA from such a source.

The Existence of DNA in Fossils Unlikely

Researchers from the Faculty of Life Sciences at The University of Manchester can now confirm that the existence of DNA in amber fossils is highly unlikely.  The team led by amber expert Dr David Penney and co-ordinated by ancient DNA expert Professor Terry Brown used highly-sensitive “next generation” sequencing techniques, the most advance type of DNA sequencing, on insects in copal, the sub-fossilised resin precursor of amber.

Ancient Insects Preserved in Amber

Scientists explore the “Jurassic Park DNA theory”.

The research was conducted wearing full forensic suits in the dedicated ancient DNA facility at The University of Manchester, which comprises a suite of independent, physically isolated laboratories, each with an ultra-filtered air supply maintaining positive displacement pressure and a managed access system.

According to Professor Brown:

“In the original 1990s studies DNA amplification was achieved by a process called the polymerase chain reaction (PCR), which will preferentially amplify any modern, undamaged DNA molecules that contaminate an extract of partially degraded ancient ones to give false positive results that might be mistaken for genuine ancient DNA.  Our approach, using “next generation” sequencing methods is ideal for ancient DNA because it provides sequences for all the DNA molecules in an extract, regardless of their length, and is less likely to give preference to contaminating modern molecules.”

Cloning Dinosaurs

The team concluded that their inability to detect ancient DNA in relatively young (60 years to 10,600 years old) sub-fossilised insects in copal, despite using sensitive next generation methods, suggests that the potential for DNA survival in resin inclusions is no better, and perhaps worse, than that in air-dried museum insects (from which DNA has been retrieved using similar techniques).  This raises significant doubts about claims of DNA extraction from fossil insects in amber, many millions of years older than the copal specimens.

Dr Penney added:

“Intuitively, one might imagine that the complete and rapid engulfment in resin, resulting in almost instantaneous demise, might promote the preservation of DNA in a resin entombed insect, but this appears not to be the case.  So, unfortunately, the Jurassic Park scenario must remain in the realms of fiction.”

Everything Dinosaur acknowledges the contribution of Manchester University in compiling this article.

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