Oldest Pine Tree Fossils Described

A pine tree is such a familiar object that it hardly deserves a second glance.  Walking in the park, driving into work, many people will pass these ubiquitous trees without giving them a thought.  Pine trees are also found in gardens, if you are mowing the lawn this weekend, stop for a moment and nod your head towards your pine as these types of tree originated at least 140 million years ago.  In addition, pine trees that dominate much of the Northern Hemisphere today might owe their success, if not their very existence to a fiery past.

Oldest Pine Fossils

Pine Trees Once Overlooked Dinosaurs

Pine trees part of the faunal landscape of the Cretaceous.

Picture credit: Natural History Museum (London)

The pine trees (Pinaceae) are a very diverse conifer genus these days, there are something like 115 species known today.  They are renowned for their ability to retain water thanks to their tough needles and their adaptations that help them withstand forest fires.  They contain highly flammable deadwood that burns very easily.

Pine Trees are Inflammable

Conifers produce terpenes, which are highly combustible organic compounds, it is these compounds that make pine trees so inflammable.  They also produce cones that will only germinate in many cases after being scorched by fire.  A new generation of pine trees can then emerge, using the nutrient rich ash left by a forest fire to sustain them and without much competition from other plants as these would have been destroyed by the conflagration.

A team of scientists from the Department of Earth Sciences at Royal Holloway (University of London), have found the oldest fossil evidence of pine trees.  The discovery was due to serendipity almost as much as hard work and dedicated research.  Dr  Howard Falcon-Lang discovered the fossils preserved as charcoal in a rock layer dated to the Valanginian faunal stage of the Cretaceous, approximately 133 to 140 million years ago.  The tiny fragments of pine tree suggest that conifers co-evolved with fire at a time when atmospheric oxygen levels were much higher than today, making forest fires much more likely and intense.

A False Colour Image of a Pine Tree Fragment Preserved as Charcoal

Fossilised pine tree fragment preserved as charcoal.

Picture credit: Royal Holloway, University of London.

A Significant Discovery

Commenting on the significance of the fossil find, Dr Falcon-Lang stated:

“Pines are well adapted to fire today.  The fossils show that wildfires raged through the earliest pine forests and probably shaped the evolution of this important tree.  Modern pines store flammable resin-rich deadwood on the tree making them prone to lethal fires.  However, they also produce huge numbers of cones that will only germinate after a fire, ensuring a new cohort of trees is seeded after the fire has passed by.”

A paper detailing the research has been published in the journal of the Geological Society of America.  The fossils had been gathered several years ago and lay unexamined in a cupboard.  It was only when the rock samples were subjected to acidification to digest the matrix material that the tiny fragments of tell-tale pine tree were revealed.  Although each specimen is only a few millimetres in length they have been interpreted as being the remains of an evergreen two-needle pine.

The research is published in the journal Geological Society of America.

Eurohippus messelensis – Fossil Reveals Ancient Foetus

The fossilised remains of an ancient, prehistoric horse that once roamed southern Germany has revealed the presence of an unborn foal.  Scanning electron microscopy of the beautifully preserved fossil has revealed the bones of a foetus, this is the oldest fossilised equine foetus discovered to date and reveals that the horse reproductive system was already highly developed by the early Middle Eocene.

Ancient Horse – Eurohippus messelensis

Ancient Horse Fossil Reveals Unborn Foal

Eurohippus foetus fossil from the Messel Shale.

Picture credit: Senckenberg Research Institute

The position of the foetus in the mare is marked by the white ellipse in the picture above.  Scale bar equals 10 centimetres.  The fossil has been set in resin, this is a standard procedure to help preserve the fossils from the Messel oil shales.

An Ancient Horse

Details of the research, conducted by scientists from the Senckenberg Research Institute (Frankfurt) and the University of Veterinary Medicine (Vienna), have been published in the academic journal PloS One.  The fossil, an early horse called Eurohippus messelensis, was excavated from the Messel Shales near Darmstadt (Germany) in 2000 but it was only after recent high resolution micro-X-ray studies in combination with the scanning electron microscopy that the 12.5 centimetre long foetus was found.

Most of the skeleton is intact (post cranial material) and elements of the placenta can be determined.  Based on a comparison with modern horses, the position of the foetus, which was near full term at the time of death, is almost identical to that seen in today’s mares which are at roughly the same stage of pregnancy.

Death of the Mare

The death of the potential mother-to-be and the unborn foal are not related to any potential complications that arose during parturition.  It seems that this little, ancestral horse that was just thirty centimetres high at the shoulder, ended up in a large, deep lake and was quickly buried in the oxygen depleted sediments at the bottom.  These sediments eventually became the oil shales which make this part of southern Germany so famous.

A Line Drawing of the Exposed Side of the Foetus

Scale bar 10 cm (A and B)

Picture credit: Senckenberg Research Institute, Jörg Habersetzer; line drawing (b) by  Jens Lorenz Franzen.

The picture above (a) shows the foetus position in relation to the bones of the adult and maps out the position of the placenta (line drawing b).

How did the Ancient Horse Die?

The oil shales of Messel contain a huge amount of fossils, both aquatic and terrestrial species, but how did this rich fossil assemblage come about?  This part of Germany was located ten degrees further south during the early Middle Eocene than it is today.  It is believed to have been a very geologically active area and infrequent releases of large concentrations of poisonous gases from the deep lakes in the area could have devastated the local ecosystem.

Deadly releases of carbon dioxide mixed with hydrogen sulphide would have quickly suffocated animals in the water and once these gases had reached land they would quickly overcome any animal in close proximity to the shore.  Corpses would have been washed into the lake by rains and eventually they would have drifted down to the bottom, where the lack of oxygen and bacteria would have facilitated their excellent preservation.  This theory also accounts for the number of bird and bat fossils found in these oil shale deposits.

Any animal flying over the lake and encountering the gas cloud would be affected and fall into the water.  Bat fossils are amongst the most numerous of all the terrestrial vertebrate fossils found at the Messel quarry site.

Such a scenario was depicted in the “Walking with Beasts” episode “New Dawn” made by the BBC.

Eurohippus (E. messelensis) is one of a number of early ungulates known from the Messel shales of Germany.

Everything Dinosaur stocks a range of prehistoric mammal models and replicas: Models of Prehistoric Mammals.

Imanai Cave – Strange Significance to Stone Age People

A team of Russian archaeologists have been putting on display some of the huge collection of prehistoric cave lion bones and other artefacts recovered from a cave in the Russian republic of Bashkiria close to the Ural mountains.  The small cave has yielded some five hundred cave lion bones so far, plus a number of flint spearheads and a cave bear skull that shows evidence of having been pierced by a spear.  The cave, known locally as the Imanai cave, shows no signs of sustained hominin habitation and it has been suggested that prehistoric people considered part of the cave to have some special, perhaps even religious significance and these items were brought into the cave deliberately.

Five Hundred Cave Lion Bones

Scientists Show some of the Flint Tools and Cave Lion Skulls

Imanai cave lion skulls on display.

Picture credit: Pavel Kosintsev

A Unique Concentration

Such a concentration of cave lion bones in the cave is unique, nowhere else in the world has such a mass concentration of cave lion bones been discovered.  The bone assemblage probably represents six individual animals.

Pavel Kosintsev, a senior researcher at the regional Institute of Plant and Animal Ecology (Urals Branch of the Russian Academy of Science) stated:

“We found about five hundred bones and fragments of bones of the giant cave lion, but there could be more, after we finish with sorting the collection.  Such a large quantity of giant cave lion bones at one site is really unique, the only one in the world so far discovered.”

Giant Cave Lions

The cave lion (Panthera leo) shares the same scientific name of the modern African lion of the savannah.  Although some scientists believe that it is sufficiently different from its African relative to be classified as a sub-species (P. leo spelaea) It may be classified as the same species, by many academics, but the cave lion looked very different from its modern African counterpart.  Panthero (leo) spelaea was around 15-20% bigger and it had longer legs.

It also possessed a thick, shaggy coat which during the winter months, when snow covered a large part of this animal’s range, that coat might well have turned white to help camouflage this large predator.  It seems that in the past, the lion as we know it today lived over a much wider area of the Northern Hemisphere.  Its range extended out of Africa and into Europe, indeed cave lion fossils have been found in the UK, most notably Kents Cavern near Torquay (Devon).

Despite their name, cave lions were not adapted to a life in caves, they were creatures of the open tundra, forests and plains.  Their bones may have been washed into caves or brought into cave dens by scavenging animals and as a result, since the bones of these large cats are associated with caves and rock overhangs the term cave lion was adopted to distinguish them from extant species.

An Illustration of a Cave Lion (note the light coloured coat)

An illustration of a cave lion.

Picture Credit: Russian Academy of Science/Pavel Kosintsev

Cave Lion Bones

Earlier excavations had found isolated bones deep inside the caves, but these were interpreted as having been sick or injured lions, or lost cubs.  The researchers believe that the cave may have been an ancient sanctuary and that these sick and injured animals could have been brought to the cave by ancient people.  This suggests that the Imanai cave had some significance to the ancient humans that inhabited this part of the Urals, perhaps it was a place of worship.  A number of other such sites were bone deposits have been made are known, the scientists hope to compare their cave data with similar sites from Austria and the Czech Republic.

The human relics found include ten stone spearheads, identified as being from the Mousterian culture, previously only two such spearheads had been found in the entire Urals region of Russia.

Inside the Cave (Imanai Cave Ural Mountains)

Going down to the bone deposit site.

Picture credit: Pavel Kosintsev

The Mousterian Culture

The Mousterian culture is defined by the style of stone tools associated with European hominins.  It relates to the Old Stone Age and dates from around 600,000 years ago with the youngest tools associated with this culture dating to around 30-40 thousand years ago.  This technology has been found in sites across southern Europe, Turkey and parts of the Middle East.  Mousterian flint tools have been discovered as far west as Wales and the Imanai cave represents one of the eastern margins for this stone tool culture.  During the Mousterian, Europe was populated by a range of hominin species, including Homo heidelbergensis, Homo neanderthalensis and latterly our own species which migrated into this part of the world from Africa – H. sapiens.

Spearheads the Only Sign of Human Activity

The spearheads and the cave bear skull with its spear hole are the only signs of human activity.  If ancient hominins had lived in this cave, even for a short period, the archaeologists would have expected to find a lot more evidence of human habitation.  For example, signs of fire having been used, animal bones with cut marks from being butchered and other stone tools.  The lack of other human artefacts supports the hypothesis that this site might have been a sanctuary of some sort or perhaps a shrine.

The latest finds have not been dated, but the upper layers of the cave floor mapped during an earlier reconnaissance are believed to be around 30,000 years old.  The lower layers are much older, how much older will have a significant bearing on the study, as the scientists cannot be sure what species of people (indeed, the cave could have been an important location to more than one type of hominin) they are dealing with.  Preliminary estimates place the lower, bone yielding layers at around 60,0000 years ago, so this site could be very significant in terms of Neanderthal research.

Different Populations of Humans

However, different populations of humans occupied different parts of Europe as the climate swung dramatically from very cold periods to much warmer inter-glacial periods during this part of the Pleistocene Epoch.  Further dating of material is currently being undertaken by scientists from the University of St Petersburg.

Archaeologists Working in the Cave at the Bone Deposit Site

Scientists carefully examining in situ evidence.

Picture credit: Pavel Kosintsev

Explaining the team’s future plans Pavel stated:

“We plan to continue the excavations next year, but the amount of finds we made this year is very large.  There are about twenty sacks with ground and small fragments and about twenty to twenty-five boxes with bones.  We need to examine all this and I think that some significant updates may appear as soon as this year.”

All the bone and tool finds come from an area of just six square metres in the cave, which has been excavated to a depth of around sixty centimetres.  The research team are excited at the prospect of exploring other parts of the cave and finding many more artefacts.  The greater the number of artefacts, then more information can be obtained which should help the scientists to understand more about the cave, its occupants and how it fitted into ancient human cultures.

Everything Dinosaur stocks a wide range of prehistoric mammal figures and models: Models of Prehistoric Mammals.

Fossilised Spermatozoa from Ancient Annelid

Dinosaurs and other large vertebrates might grab all the headlines when it comes to fossil discoveries but share a thought for those parts of the Kingdom Animalia which do not readily fossilise.  Invertebrate palaeontologists working on the Annelida (segmented worms and leeches), soft bodied creatures, have very few body fossils to study.  As a result, the dedicated scientists which work on them don’t have anything like a complete fossil record of these extremely important creatures.

Trace fossils, such as preserved burrows can help, but the evolutionary history of these ancient animals remains poorly understood.

Cocoon Fossils

In contrast, the distinctive egg cases, often referred to as cocoons of the worms that make up the Class Clitellata, are relatively common in the fossil record.  Everything Dinosaur team members have read published papers that explore the fossilised remains of the cocoons from worms that once lived in freshwater environments back in the Triassic.  These preserved cocoons provide valuable additional information as to the diversity of micro-faunas within ancient biotas.  Unfortunately, little work has been carried out so far on the possibility of using such fossils to establish phylogenetic relationships between families and genera.

Class Clitellata

The worms that make up the Class Clitellata are distinguished from other types of segmented worm, in that they have a “collar”.  It is this “collar”, called the clitellum that gives this Class its name and it is from the Clitellum that the reproductive cocoon is formed.

A Diagram of a Common Earthworm Showing the Clitellum

The clitellum is marked by an arrow.

Picture credit: Everything Dinosaur

Fossilised Spermatozoa

A team of scientists from the University of Milan, the Swedish Natural History Museum and the Museo de la Plata (Argentina) have published a paper in the academic journal “Biology Letters” that details the discovery of fossilised spermatozoa (sperm) preserved within the secreted wall layers of a fifty-million- year-old clitellate cocoon found in Antarctica.  This material represents the oldest fossil animal spermatozoa yet described.

The specimen was collected during a field expedition to the remote Seymour Island, one of a group of small islands at the tip of the Antarctic Peninsula.  The Island is extremely significant to palaeontologists as the strata exposed dates from the Late Cretaceous, the Palaeogene and into the early part of the Neogene (Eocene Epoch).  Fossils found on Seymour Island include marsupials, proving that in the past terrestrial mammals lived on Antarctica, but the rocks have proved most useful in helping scientists to plot climate change, including the global cooling during the Eocene that led to the glaciation of the Poles.

Fossil is Approximately 50 Million Years Old

Strontium isotope dating gives an age of approximately fifty million years for the fossilised spermatozoa (Ypresian faunal stage of the Eocene), the fossil find was made by chance as a single worm fragment just 0.8 mm wide was studied using a scanning electron microscope.  A three-dimensional model was then created using sections of the fragment that had been examined under X-ray microscopy.

A Fragment of the Fossilised Worm Spermatozoa

Ancient remains – scale bar = 1 micron.

Picture credit: Swedish Museum of Natural History (Department of Palaeobiology)

When closely examined, the clitellate was found to consist of a solid inner wall, just one fortieth of a millimetre thick.  In addition, there was a spongy, outer layer of loosely interwoven cables between 100th and 200th of a millimetre in thickness.  The scientists were able to observe images of the microscopic cells embedded in the cocoon wall, including rod-shaped structures with a whip-like tail.

Modestly commenting on the discovery, Benjamin Bomfleur, a palaeobotanist at the Swedish Natural History Museum remarked:

“It was an accidental find.  We were analysing the fragments to get a better idea of the structure of the cocoon.  When we zoomed into the images, we started noticing these tiny biological structures that look like sperm.”

A Worm Mystery

Working with biologists the team were able to conclude that the fossils resemble the sperm of extant freshwater crayfish worms (Branchiobdellida), although since these worms are only found in the Northern Hemisphere it remains a mystery as to whether or not the Antarctic fossil specimen is closely related.  How the fossils came to form in the first place is a little bit of a puzzle too.

Diagram Illustrating the Inferred Method of Fossilisation of Microorganism (Clitellate Cocoons)

Inferred fossilisation process.

Picture credit: Biology Letters

In the diagram above, the common medicinal leech is used to illustrate a potential theory of how the fossil preservation occurred.  Two leeches mate (a), a cocoon is secreted from the clitellum (b), then eggs and sperm are released into the cocoon before the animal retracts and eventually deposits the sealed cocoon on a suitable substrate.  Spermatozoa and microbes become encased in the solidifying inner cocoon wall (d).

The scientists anticipate that this accidental discovery will permit systematic surveys of cocoon fossils coupled with advances in non-destructive analytical techniques that will open up new opportunities to explore the evolutionary relationships of minute, soft-bodied animals that are otherwise so rarely found in the fossil record.

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