Tag: Paleontology News

Paleontology News for February 2020.

Now I’d be the first person to point out the science of paleontology is about a lot more than just dinosaurs. Dinosaurs are just one of the myriad groups of once living creatures that we only know about through their fossilized remains. Still, what kind of creature do we immediately think of when we think of paleontology? Dinosaurs that’s what! So this month’s paleontology post is all about dinosaurs.

My introduction to the science of Paleontology, many years ago! (Credit: ETSY)

Everyone knows that animals get sick just the way that we humans do. When you hear stories about swine flu or bird flu remember that those diseases are given their names because they actually came from those animals. Even extremely deadly human diseases such as smallpox and bubonic plague are actually diseases of cattle and rats respectively.

With modern instruments paleontologists can sometimes even find the telltale evidence of diseases in the fossils that they unearth. It’s actually true, Tyrannosaurids (the family of T rex) have been found with evidence of gout while osteoarthritis has been diagnosed in Iguanodons.

A recent study has been published by lead author Bruce M. Rothschild of Indiana University and the Carnegie Museum in the journal Nature. What Doctor Rothschild and his colleagues have found are lesions produced by the cancer Langerhans cell histiocytosis (LCH) in the tailbones of a duck billed Hadrosaur from Alberta Canada. The exact species of the Hadrosaur whose bones were studied could not be exactly determined because the animal’s skull was not found. 

Two tailbones of a Hadrosaur were found to possess cavities caused by cancerous tumors. (Credit: Live Science)

Now normally Langerhan cells in the body regulate the immune system but in LCH overproduction of Langerhan cells leads to the growth of benign tumors called granulomas in the bone marrow. After the death of the Hadrosaur the cancerous Langerhan cells decayed along with the animal’s normal cells so that the tumors left cavities in the dinosaur’s tailbones, cavities that could be studied using both microscopes and other instruments. Based on the evidence provided by those studies the Doctor Rothschild and his colleagues were able to determine that LCH is the closest match in form to the cavities in the Hadrosaur’s tail.

Closeup view of a tailbone. The cavity in the middle of the right view was caused by a cancerous tumor. (Credit: Live science)

Recognizing and studying the diseases that plagued animals in the past may help us to better understand how those diseases ever arose in the first place. In any case the knowledge that those animals suffered from diseases just as we do helps to remind us of one of the things that all living creatures have in common.

There’s something else that we and dinosaurs may have in common, warm blood. The possibility that dinosaurs may have evolved to have been able to maintain a warm internal body temperature has been around for about the last fifty years, and during that time a great deal of circumstantial evidence to support the idea has accumulated. Not everyone is convinced however, so each piece of new evidence strengthens the case for dinosaur warm-bloodiness.

Fossil evidence that at least some species of Dinosaurs were covered in feathers is strong support for the idea that dinosaurs were warm blooded. (Credit: NPR)

The latest discovery comes from an examination of the eggshells of cretaceous era dinosaurs in a paper published in the journal Science Advances with lead author Robin R. Dawson of Yale University’s department of Geology and Geophysics. Using a newly developed technique called ‘Clumped Isotope Paleothermometry’ the researchers measured the ordering of oxygen and carbon atoms in the wall of a fossilized eggshell as a means to determine the mother’s internal body temperature.

Hardosaur dinosaurs are know to have been good parents. The mother warming her eggs with her own body heat. (Credit: Sci-News.com)

Using this technique the paleontologists were able to measure the internal temperatures of three distinct species of dinosaurs. Troodon, a small theropod related to T rex whose body temperature was determined to be 38ºC and Maiasaura, a duck billed dinosaur whose body temperature was found to be 44ºC. The specimens for both of these species came from Alberta, Canada. The final species to have their eggshells tested is named Megaloolithus, which comes from Romania and is known only by its eggs, and whose temperature was found to be 36ºC.

Cross Sections of Dinosaur Eggshells used in the Yale study. (Credit: Sci-News.com)

Now the scientists had to be careful, remember cold-blooded means that an animal’s body temperature is the same as the ambient air around it. So if those eggs were laid on a hot summer’s day the mother’s body temperature could still have been as high as 44ºC! The researchers needed to find a control to test, the egg of a definite, known cold-blooded animal which would give a measurement of the air temperature.

Paleothermometry is one of the newest techniques that scientists have developed to glean every possible bit of information about the past from fossils. (Credit: nerdfighteria.info)

Fortunately they were able to find the necessary eggs allowing the temperature of the mother Troodon to be determined to be about 10ºC warmer than the temperature of the ambient air while the Maiasaur mother’s body temperature was 15ºC warmer. The Megaloolithus mother was also found to be 3-6ºC warmer than the air temperature. This research provides yet one more piece of evidence that dinosaurs were warm-blooded. Further advancing the argument that dinosaurs were actually more like modern birds than the ancient reptiles from whom they evolved.

Paleontology News for October 2019.

There have been some important fossil discoveries lately that span nearly the entire time period of multi-cellular life on Earth. I think I’ll start with the earliest and work my way forward in time.

We usually think of complex social behavior as being a recent development in the history of life. After all we have the most complex societies of any species and we’re one of the youngest of Earth’s creatures, right?

Humans have been social as long as we’ve been Human. (Credit: History.com)

Well it is worth remembering that some insects like ants have been living together in complex hives for around 200 million years and we now know that many species of dinosaurs traveled in herds for protection. So obviously some forms of social behavior predate human beings by quite a long time.

However some animals have been social a lot longer than we have. (Credit: Phys.org)

Now a new series of fossils from Morocco is providing evidence that social behavior existed as far back as the lower Ordovician period, about 480 million years ago. The fossils shown a large number of individuals of the trilobite species Ampyx priscus arranged in a line with the front end of their bodies all pointing in the same direction. The clear indication is that these creatures were moving together in a very orderly line, a behavior requiring considerable neural and sensory ability.

Trilobites of the species A pricus moving together in a line 480 MYA. (Credit: The New York Times)

The reason why these trilobites were moving together in a line will probably never be known for certain but the fact is that arthropod species like spiny lobsters, ants and even caterpillars are known to behave in a very similar fashion today. These trilobites provide another example of how old doesn’t necessarily imply simple or primitive. 

One of the critical events in the history of life on this planet has to be the moment when the first vertebrate animal, a fish, climbed out of the water and gingerly set foot on the land. All land dwelling bony animals, all amphibians, reptiles, including the dinosaurs, birds and mammals, including you and I are beholden to that ancient creature.

An artists illustration of what the first vertebrate to step onto land may have looked like. (Credit: Phys.org)

So it’s not surprising that paleontologists are keenly interested in learning as much as they can about those early land vertebrates. The recent discovery of a new species of tetrapod, that is a four-limbed animal, gives an insight into what kind of creature may have been the first to make that historic step. Discovered in the Sosnogorsk formation along the banks of the Izhma River in the former Soviet Republic of Komi the animal has been dated to about 372 million years ago during the Devonian Period.

Artists impression of the recently discovered Terapod from the Komi Republic. (Credit: Daily Mail)

Named Parmastega aelidae the animal is a strange mixture of both fish and land animal characteristics. For example the placement of its eyes on the top of a flat skull clearly indicates an animal that is watching what is going on above the waterline. At the same time however the animal’s shoulder girdle is made of partially cartilaginous bones, making those bones too weak to be able to support a land animal. So P aelidae may have been a water animal whose prey lived out of the water. A modern example would be a crocodile and indeed the long snout filled with sharp teeth of P aelidae strongly resembles that of a crocodile.

A comparison of the skull of the terapod (r) to that of a modern crocodile (l). (Credit: Daily Mail)
A fossil jawbone of the terapod showing numerous sharp teeth. (Credit: Phys.org)

The discovery of such fossils as P aelidae gives us further knowledge in our quest to understand how our ancestors evolved to become the dominant kind of life on land.

Another critical moment in the history of life on Earth surely came after the asteroid collision that led to the extinction of the dinosaurs along with 75% of all species of life. The questions of how quickly did life recover from that disaster, and what kind of animals became dominant now that the dinosaurs were gone are key to our understanding the natural world today? Paleontologists know that in order to answer these questions they need to find fossil sites from the time immediately after the asteroid strike.

The asteroid that killed the dinosaurs landed in the Yucatan peninsula of Mexico forming a crater 300 km wide. (Credit: Research.utexas.edu)

Just such a fossil site was recently discovered by paleontologists Tyler Lyson and Ian Miller of the Denver Museum of Nature and Science just outside the nearby city of Colorado Springs. The location, known as Corral Bluff is yielding a treasure trove of fossils from a time less than a million years after the asteroid strike. The finds include over 1,000 mammal fossils from 16 different species along with reptiles, birds and 6,000 plant fossils. The most important finds discovered by the researchers consisted of dozens of delicate mammalian skulls.

Doctors Lyson (r) and Miller (l) searching for mammal fossils at Corral Bluff. (Credit: KPBS)

While the fossils are still being studied a few conclusions can be reached. During the reign of the dinosaurs mammals remained small, rare and nocturnal creatures no larger than a squirrel, about one kilogram maximum. The fossils obtained from Corral Bluff however show that is less than a million after the dinosaurs were gone mammals had already greatly increased in both size and number with one of the species discovered estimated as having a mass more than 50 kg.

Artists impression of one of the little mammals that repopulated the world after the extinction of the dinosaurs. (Credit: USA Today)
Some of the mammal fossils found at Corral Bluff. (Credit: Reuters)

The fossils from Corral Bluffs give witness to how quickly the mammals were evolving to fill up the ecological niches left vacant by the extinction of the dinosaurs. At the same time the paleontologists are making other discoveries as well, among them the remains of the earliest known legume, a pea plant that might very well have provided high protein food for some of the growing population of mammals.

The history of life on Earth is both long and complex but paleontologists don’t mind that at all. It just mean that there are many more fascinating discoveries waiting to be made.

Paleontology News for August 2019: Special Trilobite edition

A couple of new discoveries have recently been published about the ancient and extinct sea creatures known as trilobites so I thought that this would be a good opportunity to discuss these fascinating creatures in some detail. I’ll begin with a few general facts about trilobites.

The Trilobite Phacops rana, the state fossil of Pennsylvania (Credit: Flickr)

First of all trilobites are members of the phylum arthropoda, the jointed limbed animals that include crustaceans, insects and spiders. In fact trilobites are generally recognized as the earliest members of that group of animals with fossils going back as far as 540 Million years ago. Trilobites not only evolved a long time ago they also went extinct a long time ago. The last trilobites died in the Permian extinction event about 250 million years ago, see my posts of 16 February 2019 and 2 June 2018. That’s several million years before the first dinosaur ever evolved!

Because trilobites lasted so long, and their exoskeleton fossilized so easily paleontologists have been able to identify more than 50,000 different species. During their almost 300 million year existence trilobites evolved to occupy nearly all of the ecological niches occupied by modern marine arthropods including that of scavenger, predator, filter feeder and even a swimming species that fed off of the plankton near the surface.

Looking at the figure below, you can see that Anatomically trilobites are defined by their broadly oval shape and the three main sections of their body going side to side, right pleural lobe, axial lobe, which is often raised, and left pleural lobe. Many people incorrectly think that the three lobes of the name trilobite refer to the three sections going front to back with the cephalon (head), thorax and pygidium (tail). (I did when I was young!)

The main anatomic parts of a Trilobite (Credit: Wikipedia)

Early trilobites, such as Olenellus from the Cambrian period seen below, had a cephalon that was much larger than their pygidium. As trilobites evolved however their tails grew to almost the same size and shape as their head as seen below in Phacops from the Devonian period. This adaptation allowed later trilobites to roll up into a protective ball in much the same way as a modern armadillo does. Fossils of such rolled trilobites are often found in Devonian, Mississippian and Pennsylvanian rocks.

The Cambrian Trilobite Olenellus fremonti (Credit: American Museum of Natural History)
An enrolled specimen of Phacops rana (Credit: Fine Art America)

With a history of 300 million years and at least 50,000 species trilobites varied considerably in their particulars, especially size and ornamentation, see images below. The largest known trilobites are from the genus Isotelus of the Ordovician period some 450 million years ago specimens of which are as long as a meter. There are a number of candidates for the smallest member of the group but many small trilobites were no larger than a pea.

A beautiful specimen of Isotelus maximum (Credit: Geoclassics)
A species of Trilobite ornamented with spines, presumably for protection (Credit: Tack Raccoons)
Another spiny trilobite (Credit: Catawiki)

For the most part however trilobites remained rather conservative in their basic body plan. This may have contributed to their eventual extinction as competitors such as crustaceans and fish evolved structures like jaws and manipulating pincers that allowed them to outperform the trilobites.

As fossils a complete trilobite is fairly rare, one or two can represent a good day’s hunting. On the other hand recognizable pieces of trilobites are very common. The reason for this is that like all arthropods trilobites had to molt in order to grow. So a single live trilobite could in the course of its life produce many empty shells that would quickly break up to produce a lot of trilobite pieces.

Fragments of many fossils including a Trilobite tail right in the middle (Credit: The fissil forum)

A couple of recent studies have further increased our knowledge of these ancient creatures. The first concerns the discovery of a new species of trilobite from Australia that has been named Redlichia rex. The name is a reference to the well known dinosaur Tyrannosaurus rex because of R rex’s large size, 30cm, and leg spines that could be used to crush the trilobites food. The fossils of R rex come from the Emu bay shale of Australia’s Kangaroo island and are exceptionally well preserved revealing details of even the animal’s delicate antenna, see image below.

Artists impression of Redlichia rex along with a fossil specimen (Credit: Species new to Science)

Because of R rex’s large size and crushing legs it is believed that the trilobite was a predator, and perhaps even a cannibal. Specimens of R rex have been found with healed injuries so the question is, what could have preyed on these large, for the Cambrian period, animals. While there are several possibilities it has also been suggested that R rex may have preyed on its own kind!

The second discovery also comes from a fossil site that is well known for exceptionally well-preserved specimens, the Guanshan location in eastern Yunnan province China. In this study it’s not a new species of trilobite that’s been announced, it’s the discovery of the earliest known evidence for a stomach and digestive system!

Using some of the best specimens of the trilobite Palaeolenus lanteroisi, see image below, researchers from the American Museum of Natural History in New York and the Early Life Institute at Northwest University in Xi’an China actually succeeded in ‘dissecting’ the fossils. That is, they have managed to carefully remove a portion of the upper layers of the fossil in order to examine the petrified remains of the animal’s internal organs.

Examples of dissections performed on fossils of long dead Trilobites (Credit: Hopkins, Chen, Hu and Zhang)

What they found was a well-developed digestive system with a large stomach or ‘crop’ in its cephalon. That’s right trilobites appear to have had their stomach’s in their heads not far from their mouths!  A long alimentary canal then went through the length of the rest of the trilobite’s body to an anus at the animal’s posterior. Trilobites have a special place in the history of life, as one of the first complex, multi-cellular forms of animal they dominated the ancient Cambrian and Ordovician seas. Thereafter they gradually declined, finally becoming extinct during the Permian catastrophe. Nowadays for any fossil hunter a good trilobite specimen will always be a small prize to be treasured.

Paleontology News for May 2019: Two new interesting species of dinosaurs discovered.

Most people know that the dinosaurs dominated Earth for over 150 million years but of course it wasn’t just one species of dinosaur and not all of the dinosaurs were so dominating. Some species were smaller, more inconspicuous relatives of the better-known giants while others represented evolutionary experiments that, for one reason or another simply did not leave any descendents, in other words they were experiments that failed.

I’ll start with the recent discovery of a relative of the famous Tyrannosaurus rex discovered in New Mexico by Dr. Sterling Nesbitt of Virginia Tech College of Science’s Department of Geosciences. Named Suskityrannus hazelae the two-legged theropod likely measured about 2.7 m from the tip of its nose to the end of its tail and stood less than a meter tall at the hip. This small meat eating would have weighted between 20 and 40 kg and likely hunted smaller animals.

An Artist’s illustration of Suskityrannus hazelae (Credit: Andrey Atuchin)

According to Dr. Nesbitt, “Suskityrannus hazelae gives us a glimpse into the evolution of tyrannosaurs just before they take over the planet.” Based on the geologic strata in which it was discovered S hazelae lived some 92 million years ago near the beginning of the Cretaceous period. Because of the time it lived along with its anatomy S hazelae could prove to be a link between the older and smaller tyrannosauroids of North America and China and the much larger tyrannosaurids of which T rex is the best-known member.

Dr. Sterling Nesbitt with the bones of S hazelae (Credit: Virginia Tech)

The second new species of dinosaur to be discovered is rather a bit stranger. Ambopteryx longibrachium is a species of theropod dinosaur that flew, or perhaps only glided, with leathery bat like wings. Now I’m not talking about one of the pterosaurs, those bat like reptiles that lived at the same time as the dinosaurs but which weren’t dinosaurs.

The flying reptiles known as Pterosaurs were not dinosaurs! Their anatomy is different! (Credit: Iraber.info)

A longibrachium is a theropod, the same group of dinosaurs that includes T-rex and from which the true flying dinosaurs, better known as birds, would come. In fact A longibrachium lived approximately at the same time as the first birds, the late Jurassic period some 163 million years ago, about the same time as the famous Archaeopteryx.

Artist’s illustration of what Ambopteryx Longibrachium may have looked like (Credit: Smithsonian)

The fossils of A longibrachium are remarkably well preserved not only showing the membrane of their leathery wings but also the impressions of fuzzy feathers that were probably helped to keep the animal warm. The most critical part of the anatomy to be preserved was an enlarged, rod like wrist bone known as a styliform, an adaptation previously unknown in dinosaurs but present in pterosaurs and flying squirrels.

The actual fossil of A longibrachium. The leathery wings are quite obvious (Credit: Discovery Magazine)

The fossil remains of A longibrachium were discovered in China by scientists at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences. Over the last few decades there has been a lot of paleontological research underway in China with important discoveries being made in many different periods of Earth’s history. (See my post of 10 April 2019)

Ambopteryx longibrachium fits into the evolutionary tree of small theropods very closely to those who would become the birds! (Credit: Nature)

So what happened to the dinosaurs like A longibrachium? Well perhaps the bat winged dinosaurs lost out to their relatives the evolving true birds. Or perhaps there was some ecological crisis that the bat winged dinosaurs failed to survive. We can’t say at present, but you can be certain that the paleontologists will keep searching for the answers, and isn’t that what science is all about!