Palaeogene Diatryma a Vegetarian

With the extinction of the Dinosauria at the end of the Cretaceous there were a huge number of ecological niches vacated by the likes of the ornithopods and the theropods.  For example, with the demise of the dromaeosaurs, abelisaurids and the tyrannosaurids there were no large, entirely terrestrial predators left on Earth.  Many scientists have accepted the theory that flightless birds evolved into apex predators, replacing the meat-eating dinosaurs.  One such flightless bird, was the giant Gastornis (sometimes referred to as Diatryma).

Standing over 1.75 metres tall, (some scientists suggest that some specimens were over 2.2 metres high), this heavily built bird was believed to be a predator, specialising in ambushing small mammals and other creatures despatching them with its massively powerful beak.  However, a team of Washington based scientists have proposed that these giant birds were actually gentle herbivores.

An Illustration of Diatryma/Gastornis

Picture credit: Everything Dinosaur

An examination of three-toed footprints uncovered after a landslide in 2009, that are believed to have been made by a Diatryma-like flightless bird, show that this huge bird did not possess raptor-like claws.  The lack of sharp claws could mean that the the huge beak of these birds may not have been the bone-crunching, mammal eating weapon thought of previously, but the sturdy beaks could simply have evolved to crush nuts and fruit.  The American scientists propose that these bipeds may have been entirely vegetarian.

Bird Footprints

The bird footprints, were found in sandstone strata of the Chuckanut Formation of Whatcom County (north-western Washington).  The tracks were uncovered after a landslide and the strata in this formation dates to the Palaeogene geological period (Lower Eocene around fifty million years ago).  The environment was a sub-tropical, flood plain, criss-crossed by many large rivers.  The footprints were made by a large, flightless bird as it walked along a riverbank.  There were crocodiles and many different types of turtles as well as other species of birds and many small mammals in this environment.

Researchers from Western Washington University, (Bellingham, Washington State), examined the tridactyl prints (three-toed) and have ascribed them to the ichnogenus Rivavipes giganteus, placed in the family of Gastornithidae.  An ichnogenus is a genus which is established after the study of fossilised footprints or tracks.

Footprints show no Trace of Talons

Picture credit: D. Tucker/Western Washington University

Giant Birds

Fossils of giant birds dating from the Palaeocene and Eocene Epochs have been found in Europe and the United States.  The shape of the beak and the sturdy, muscular body led palaeontologists in the 19th Century to describe these birds as predators, the first of the “Terror Birds”.  However, researchers at the American Museum of Natural History (New York), at the end of the 20th century proposed that creatures such as Gastornis and Diatryma may have lunched on fruit and seeds.

This theory was based on the shape of the beak, which they interpreted as being well suited to crushing nuts and other tough plant matter rather than for the tearing of meat.  Unlike many predatory birds of today, the beak did not have a curved downward pointing tip.  Although the beak was very strong, it did not have the same morphology as those of meat-eating, extant birds such as eagles and ospreys.  This contradicted an earlier paper, published in 1991 by American palaeontologists Lawrence Witmer and Kenneth Rose which focused on the biomechanics of the bill of Diatyrma.  Witmer and Rose postulated that the powerful jaw muscles and thick bill could only have evolved to crush bone.

One of the authors of the scientific paper describing the footprints, that has just been published in the academic journal “Palaeontology”, George Mustoe stated:

“Let’s be honest, scary, fierce meat-eaters attract a lot more attention than gentle herbivores”.

Studying the Tracks

The tracks show that the bird that made these prints did not have long talons.  Such short claws do not seem suited to catching and subduing prey.  Carnivorous birds all have sharp, pointed long talons.  The short leg bones of Diatryma/Gastornis suggest that this heavy creature, that could have weighed in excess of 400 kilogrammes, would not have been a fast runner.  It had been thought that it was a specialist ambush predator, but perhaps it did not need to move very quickly, simply browsing on the plentiful fruit and nuts to be found in the forest.

Washington State around Fifty Million Years Ago – Grazing Giant Birds

Picture credit: Marlin Peterson

The lack of sharp claws on the feet adds to the theory that flightless birds such as Diatryma may have been entirely herbivorous and not the “Terror Birds” as previously thought.   According to the Western Washington University scientists, the assumption that Gastornis/Diatryma was a meat-eater, relates to anatomical similarities seen in the later phorusrhacids from South America.

There have been a number of “Terror Bird” models made in recent years, perhaps the most famous is the Bullyland Diatryma/Gastornis, but Safari Ltd will be bringing out a Gastornis replica in 2013, a new addition to their “Prehistoric Life” model series.

New Gastornis Replica Available in 2013

Picture credit: Everything Dinosaur

To view Everything Dinosaur’s range of prehistoric animal models including replicas of Kelenken and Diatryma: CollectA Deluxe/Supreme Prehistoric Animal Replicas.

If the likes of Diatryma/Gastornis were not carnivorous, then this leads us to an interesting conundrum – what type of creatures were the apex predators during the Palaeogene?

Researchers Discover Fossils of Giant Penguin in Antarctica

A team of researchers from the Natural Sciences Museum of La Plata Province (Argentina), have uncovered the fossilised remains of a giant penguin at the start of a summer expedition to Antarctica.  The fossils indicate that this particular type of flightless bird stood around 6 feet 5 inches tall (nearly two metres high), making it the largest penguin known to science.

Giant Penguin Fossils

Researcher Carolina Acosta, compared this new fossil find to the largest extant penguin species, the Emperor Penguin (Aptenodytes forsteri) which can weigh up to forty-five kilogrammes and stands around four feet (1.2 metres) high.

She stated:

“This is the largest penguin known to date in terms of height and body mass.”

Earlier this year, scientists from the Ashoro Museum of Palaeontology (Japan) uncovered the fossils of two new species of prehistoric penguin from the Waitaki region of New Zealand.  One of these species Kairuku grebneffi, was estimated to have stood nearly five feet tall (1.5 metres) and may have weighed as much as 130 lbs (60 kilogrammes).  At the time of this discovery, this species was declared the largest known in the fossil record, but this new discovery from Antarctica indicates an even larger prehistoric flightless bird.

Fossil Discovery in Antarctica

Giant penguin fossil discovery.

Picture credit: Natural Sciences Museum of La Plata Province

A More Intensive and Complex Study of Modern Penguins

Head of Collections at the Natural Sciences Museum of La Plata, Dr Marcelo Reguero, when asked to comment on the new fossil discovery stated that the work of the research team:

“will allow for a more intensive and complex study of the ancestors of modern penguins”.

There are plans to re-visit the location next summer when the weather in Antarctica would be more conducive to a scientific expedition.  The fossils date to around thirty-four million years ago (Oligocene Epoch), at this time the world was warmer than it is today, however, changes were occurring in the Southern Ocean.  The continent of Antarctica had finally split away from other landmasses that once made up the super-continent known as Gondwanaland.  Antarctica was now roughly in the position it occupies today, sitting on the southern pole of the planet.

Surrounded by water and with sun for little over half a year, the continent began to undergo a transformation and for the first time in hundreds of millions of years, ice sheets began to form and permanent ice could be found at the South Pole.

Looking for More Fossil Evidence

In its next expedition to Antarctica, during the region’s summer, the team will seek additional fossils of the newly discovered species, as well as information about its anatomy and how the giant penguin might have moved.  The palaeontologists are confident that this species had a similar diet to that of modern penguins, spearing fish and cephalopods with its seven inch long (18 centimetre) sharp beak.

Previous finds from prehistoric penguins indicated they did not sport the iconic black and white feathers the birds are known for today, but had reddish-brown and grey plumage.

For models and replicas of prehistoric animals including theropod dinosaurs: Prehistoric Animal Models and Replicas (PNSO).

Archaeopteryx – Mainly a Glider say Research Team

A team of international researchers, scientists from the University of Bristol, the United States and the Beijing Museum of Natural History (China), have concluded that Archaeopteryx (A. lithographica) was more of a glider than a flapping flier, able to take-off from the ground.  An analysis of the structure and composition of the wings of this Late Jurassic animal suggests that the wings although covered in feathers, were very different when compared to the modern wing of an extant bird, a member of the Neornithes.

Archaeopteryx

This new research, published in the academic journal “Current Biology”, proposes that the earliest forms of creature, evolving towards the Aves (birds) had layers of rigid feathers on their wings that made up an aerofoil surface which provided lift.  In the past, palaeontologists had assumed that the composition of the wing of Archaeopteryx was the same as modern birds, that wings were essentially modified forelimbs that were covered in a single layer of long, asymmetrical flight feathers with shorter, covert feathers on top.  Modern birds are able to use their wings to obtain lift, thrust and to manoeuvre by separating their feathers and rotating them.  This new study suggests that primitive, transitional birds such as Archaeopteryx may have been effective gliders, rather than creatures capable of true, powered flight.

Archaeopteryx fossils must be some of the most closely studied objects known to science.  Recently, there have been a number of exciting, scientific papers published about this enigmatic creature, for example, palaeontologists have been able to work out what this animal may actually have looked like.

To read an article about the colour of Archaeopteryx:  sets: Archaeopteryx – The World’s Oldest Black Bird?

Named and Described in 1861

The crow-sized Archaeopteryx was named and described by the German palaeontologist Hermann von Meyer in 1861.  The first fossil evidence of Archaeopteryx that came to the attention of science was a single, fossilised feather that was found in 1860.  A second fossil showing much of the skeleton and the fossilised impressions of feathers around the wings and tail was uncovered in 1861.  This specimen was purchased by Sir Richard Owen (the founder of the Natural History Museum in London); he paid £700 for it – a huge sum of money in those days.  This fossil has become known as the London specimen.  In total only a handful of Archaeopteryx fossils have been found (seven specimens and one fossil feather).  The first Archaeopteryx fossil was found in 1855, but at the time it was wrongly classified as a pterodactyl (flying reptile), it was finally classified as a fossil of Archaeopteryx in 1970.  In 1859, Darwin published his theory of evolution “The Origin of Species”, he argued that species gradually evolved and changed in response to their environments and other factors and that this led to new speciation.  The discovery of a feathered creature with wings like a bird but teeth and a tail like a reptile, was taken as evidence to support Darwin’s theory of natural selection.

Fossils of Archaeopteryx Provide Vital Clues to the Evolution of Powered Flight in Vertebrates

The left wing of Archaeopteryx with accompanying line drawings.

Picture credit: Longrich et al Current Biology.

Studying Archaeopteryx Specimens

The research team studied a number of Archaeopteryx specimens, including the famous “Berlin” specimen.  These fossils were compared and contrasted with the remains of a feathered, ground-dwelling, cursorial dinosaur known as Anchiornis (A. huxleyi).  Anchiornis was a crow-sized dinosaur that lived in north-eastern China approximately 160 million years ago, a few million years before Archaeopteryx evolved.  A number of specimens are known, all of which have come from the famous Liaoning Province of China.  This little reptile was covered in feathers.  It had long feathers on its arms and legs making a sort of fore and hind wing arrangement similar to that seen in another Chinese dinosaur Microraptor (Microraptor gui).  The research team conclude that feathers first evolved for insulation, thus supporting the theory that many dinosaurs were warm-blooded (endothermic).  Some feathers became display structures for courtship and other purposes and only later, around 130 million years ago did the modern wing structure evolve.

An Illustration of Archaeopteryx (Museum Exhibit)

An Archaeopteryx (A. lithographica) model on display.

Picture credit: Everything Dinosaur

To view replicas of Archaeopteryx and other types of theropod dinosaur: PNSO Dinosaur and Theropod Models.

The wing function of Archaeopteryx may represent a transition from a cursorial lifestyle to that of a modern flying bird, the layers of feathers being a sort of early evolutionary experiment in wing design.  Although the individual feathers of Archaeopteryx may have been quite weak (indicated by the thin rachis (feather shaft)), the layered effect of the wing would have provided a relatively efficient aerofoil structure for the animal to use when gliding from tree to tree.  Not being able to separate feathers as birds can do today, would have limited Archaeopteryx’s flying skills.  Taking off from the ground and flapping vigorously at low speeds may have proved very difficult for this little creature.

Dr Jakob Vinther, of the University of Bristol (School of Biological and Earth Sciences), commented:

“We are starting to get an intricate picture of how feathers and birds evolved from within the dinosaurs.  We now seem to see that feathers evolved initially for insulation.  Later in evolution, more complex vaned or pinnate feathers evolved for display.

“These display feathers turned out to be excellent membranes that could have been utilised for aerial locomotion, which only very late in bird evolution became what we consider flapping flight.  This new research is shedding light not just on how birds came to fly, but more specifically on how feathers came to be the way they are today – one of the most amazing and highly specialised structures in nature.”

Early Birds

One of the authors of the research paper, Dr Nicholas Longrich of Yale University added that as a result of carefully studying these Middle and Upper Jurassic fossils, scientists are able to conclude that early birds had more primitive wings than their modern counterparts.  Over the next thirty million years or so, the wing structure gradually evolved and become a more efficient organ of flight.  The wings of birds from sediments deposited 130 million years ago are essentially identical to those of modern, extant Aves.

To read an article about the discovery of Anchiornis: Is Archaeopteryx about to be Knocked off its Perch?

Although, the wings of early, transitional creatures such as Archaeopteryx may have lacked the range of functions seen in Neornithes today, it is interesting to note that there is one type of bird today that has a similar, layered structure of feathers on its wing – the Penguin.  Penguins, originally descended from birds that could fly, but they have lost their ability to take to the air, and the layers of feathers are used to insulate their bodies from the cold.  Thus the feathers found on extant Penguins perform a very similar function to those seen on the Middle Jurassic dinosaur Anchiornis, they are primarily used for insulation.

Everything Dinosaur acknowledges the assistance of a media release from the University of Bristol in the compilation of this article.

The scientific paper: “Primitive Wing Feather Arrangement in Archaeopteryx lithographica and Anchiornis huxleyi” by Nicholas R. Longrich, Jakob Vinther, Qingjin Meng, Quangguo Li and Anthony P. Russell published in Current Biology.