Ancient saber-toothed cat skull discovery in Germany


This video says about itself:

12 August 2015

“Homotherium” is an extinct genus of machairodontine saber-toothed cats, often termed “scimitar-toothed cats”, that ranged from North America, South America, Eurasia, and Africa during the Pliocene and Pleistocene epochs.

It first became extinct in Africa some 1.5 million years ago. In Eurasia it survived until about 30,000 years ago. In South America it is only known from a few remains in the northern region, from the mid-Pleistocene. The most recent remains of Homotherium date to 28,000 years BP.

Homotherium” reached 1.1 m at the shoulder and weighed an estimated 150 [kilogram] – and was therefore about the size of a male African lion. Compared to some other machairodonts, like “Smilodon” or “Megantereon”, “Homotherium” had shorter upper canines, but they were flat, serrated and longer than those of any living cat. Incisors and lower canines formed a powerful puncturing and gripping device. Among living cats, only the tiger has such large incisors, which aid in lifting and carrying prey. The molars of “Homotherium” were rather weak and not adapted for bone crushing. The skull was longer than in “Smilodon” and had a well-developed crest, where muscles were attached to power the lower jaw. This jaw had down-turned forward flanges to protect the scimitars. Its large canine teeth were crenulated and designed for slashing rather than purely stabbing.

It had the general appearance of a cat, but some of its physical characteristics are rather unusual for a large cat. The limb proportions of “Homotherium” gave it a hyena-like appearance. The forelegs were elongated, while the hind quarters were rather squat with feet perhaps partially plantigrade, causing the back to slope towards the short tail. Features of the hind limbs indicate that this cat was moderately capable of leaping. The pelvic region, including the sacral vertebrae, was bear-like, as was the short tail composed of 13 vertebrae—about half the number of long-tailed cats.

From the Senckenberg Research Institute and Natural History Museum in Germany:

Skull of saber-toothed cat found almost complete

Third individual saber-toothed cat was discovered in Schöningen

April 12, 2017

Summary: An excavation team found the remains of a saber-toothed cat at the archeological site in Schöningen. An examination of the skull fragments revealed the animal to be a representative of the European saber-toothed cat, Homotherium latidens. The recent discovery constitutes the third example of this large predatory cat from Schöningen.

Led by scientists of the Senckenberg Research Institute and the University of Tübingen, the excavation team found the remains of a saber-toothed cat at the archeological site in Schöningen. An examination of the skull fragments at the Dutch University of Leiden revealed the animal to be a representative of the European saber-toothed cat, Homotherium latidens. The recent discovery constitutes the third example of this large predatory cat from Schöningen.

Long claws, razor-sharp, curved canine teeth and the size of a fully grown lion: the saber-toothed cat (Homotherium latidens) was a competitor as well as a dangerous predator that even posed a risk to the humans of its time. “In the course of our excavation in May 2015, we came across conspicuous bone fragments,” explains Dr. Jordi Serangeli, a scientist at the University of Tübingen and the excavation leader at the approximately 300,000-year-old archeological site, and he continues, “In total, there are three individuals of Homotherium present in these relatively young sediment layers.

Until the first discovery of a saber-toothed cat in 2012 at the Schöningen excavation site in Lower Saxony it had been assumed that the large cats were already extinct about 200,000 years earlier, i.e., around 500,000 years ago. “Our findings show that 300,000 years ago, the saber-toothed cats were not as rare as previously thought,” adds Serangeli.

During a restoration in 2016, André Ramcharan and Ivo Verheijen at the University of Leiden were able to reassemble the eleven bone fragments into an almost complete neurocranium. “We then compared the reconstructed skull with recent and already extinct species of large carnivores and were thus able to demonstrate that the remains represented the head of a European saber-toothed cat,” explains Professor Dr. Thijs van Kolfschoten of the University of Leiden.

The third saber-toothed cat specimen that was discovered offers a great potential: thanks to the excellent level of preservation at the Schöningen dig, the interior of the skull reflects the shape and structure of the Homotherium brain. By examining the detailed brain structures, the team of scientists hopes to gain insights into the visual and hearing abilities as well as the feeding habits of the large cats. “The third Homotherium from Schöningen is invaluable for our understanding of the European saber-toothed cat,” summarizes Professor Nicholas Conard of the Senckenberg Centre for Human Evolution and Palaeoenvironment and head of the Institute for Early Prehistory and Quaternary Ecology at the University of Tübingen.

In the near future the international team from the Schöningen project intends to publish the results of its interdisciplinary studies regarding the three saber-toothed cats discovered to date. “Moreover, we expect that future digs will produce additional Homotherium finds,” offers Serangeli as a preview.

The dig in Schöningen keeps a team of ten members employed full-time — and during the main excavation season, the team is joined by five to ten students, who support the scientific excavation. Worldwide, about 50 scientists from 30 institutions and a wide variety of disciplines are involved in researching the discoveries from Schöningen. The dig is financed by the State of Lower Saxony.

The spectacular new discovery is put on display for the public at the palaeon in Schöningen as part of the special exhibition “The Ice Age Huntress.” Thanks to the close cooperation between Senckenberg, the international partners and the der palaeon GmbH, it is possible to make spectacular scientific findings available to the public in a timely manner.

Fossil marsupials discovery in Bolivia


This video says about itself:

24 April 2015

The Evolution Of Mammals

Description: The word “mammal” is modern, from the scientific name Mammalia coined by Carl Linnaeus in 1758, derived from the Latin mamma (“teat, pap”). All female mammals nurse their young with milk, which is secreted from special glands, the mammary glands.

According to Mammal Species of the World, 5,416 species were known in 2006. These were grouped in 1,229 genera, 153 families and 29 orders.[1] In 2008 the IUCN completed a five-year, 1,700-scientist Global Mammal Assessment for its IUCN Red List, which counted 5,488 accepted species at the end of that period.[2] In some classifications, the mammals are divided into two subclasses (not counting fossils): the Prototheria (order of Monotremata) and the Theria, the latter composed of the infraclasses Metatheria and Eutheria. The marsupials constitute the crown group of the Metatheria and therefore include all living metatherians as well as many extinct ones; the placentals likewise constitute the crown group of the Eutheria.

From Case Western Reserve University in the USA:

Three new species of extinct South American marsupials discovered

Findings show the family, Palaeothentidae, was once widespread across the continent but add to extinction doubts

April 11, 2017

The discovery of three extinct species and new insights to a fourth indicates a little-known family of marsupials, the Palaeothentidae, was diverse and existed over a wide range of South America as recent as 13 million years ago. Fossils of the new species were found at Quebrada Honda, a high elevation fossil site in southern Bolivia, and are among the youngest known palaeothentid fossils.

The discovery of three extinct species and new insights to a fourth indicates a little-known family of marsupials, the Palaeothentidae, was diverse and existed over a wide range of South America as recent as 13 million years ago.

The finding, however, complicates the question: why did these animals go extinct?

“It was previously assumed this group slowly went extinct over a long time period, but that’s probably not the case,” said Russell Engelman, a biology MS student at Case Western Reserve and lead author of a new study on the group. “They were doing very well at the time they were supposedly on death’s door.”

Discovering new fossil sites may be the only way to learn the answer, researchers say.

Engelman; along with Federico Anaya, professor of geological engineering at Universidad Autónoma Tomás Frías, in Potosí, Bolivia; and Darin Croft, anatomy professor at Case Western Reserve School of Medicine, describe the animals, where they fit in the family, and their paleoecology and paleobiology in the Journal of Systematic Palaeontology.

Fossils of the new species were found at Quebrada Honda, a high elevation fossil site in southern Bolivia. They are about 13 million years old (from the middle Miocene epoch), placing them among the youngest known palaeothentid fossils.

Fossil remains of other members of the family, and other relatives within the order Paucituberculata, have been found at sites of similar age in southwestern Colombia and possibly southern Argentina, geographically spanning almost the entire continent.

“The only close relatives of palaeothentids alive today are shrew opossums, small, poorly-known, ground-living marsupials that live in and near the Andes,” Croft said. “Palaeothentid marsupials once included a diversity of species that filled a variety of roles in ancient ecosystems. During their heyday in the Miocene, they were abundant.”

The new species, Palaeothentes serratus, Palaeothentes relictus, and Chimeralestes ambiguus, all had long snouts but differed in diet and body size and other features.

The researchers suggest P. serratus — serratus means saw-like — was an insectivore, with well-developed slicing premolars. The researchers estimate the mouse-size marsupial weighed about 3.5 ounces.

P. relictus had large, well-developed grinding molars. The animal probably ate fruits, seeds and insects, and weighed about five ounces.

C. ambiguus, as the name indicates, has attributes of a number of family members, making its evolutionary relationships with the group uncertain. The animal was about the same size as P. serratus and its limited dental remains indicate its diet was likely similar to that of P. relictus.

The most common member of the family found at Quebrada Honda is Acdestis maddeni. The species was named 14 years ago, but the researchers are the first to find and analyze its lower jaw.

These lower jaw fossils, combined with reexamination of other specimens, show that the skull of Acdestis was different from other palaeothentids. A. maddeni’s snout is short and its canines are relatively large, followed by large, shearing middle teeth and molars well developed for grinding.

“All this indicates it was a generalist,” Engelman said. “Although it could eat fruits and insects like its relatives it could also catch small vertebrates and dismember them… It probably ate anything, like a hedgehog or Norway rat does.”

The animal was rat-size and weighed about a pound, the researchers estimate.

The fossil record indicates the Palaeothentidae and much of the order Paucituberculata abruptly went extinct about 12 million years ago, leaving only the lineage leading to modern shrew-opossums.

“Most species threatened with extinction are like giant pandas: highly specialized, live only in a certain area and eat only certain things,” Engelman said. Due to their diversity and wide range, “the Palaeothentidae didn’t fit the pattern of extinction.”

Previous hypotheses that palaeothentids were done in by climate change or competition lack support, the researchers say.

For example, fossils found at high latitudes in Argentina and Bolivia after the Middle Miocene Climatic Optimum indicate they withstood the dramatic cooling of the period. The family and opossums, which may have been competitors, appear to have overlapped for nearly 10 million years. Yet opossums didn’t become abundant until 3 million to 4 million years after the family went extinct.

But, the hypothesis cannot be completely ruled out, the researchers said. And, there is a possibility the decline of the family was slow.

The reason for the quandary is that fossils have been well collected in the southern end of South America but the middle and northern parts of the continent remain largely unexplored.

“It’s as if all the fossils in the U.S. came from Florida — you don’t get the full picture,” Engelman said.

If new fossil sites are found in the northern two-thirds of the continent, “it will be interesting to see whether we find younger members of the group,” Croft said. “That will help us understand their extinction.”

World’s oldest amphibian fossil in Scotland?


This video from the USA says about itself:

13 September 2016

In this lecture I will highlight five Devonian fossils that represent steps along the transition to a fully terrestrial tetrapod. You should be able to arrange a cladogram of Devonian tetrapods and illustrate the changes in anatomy that occurred during the transition toward living on land.

By Anna Buckley, BBC Science Radio Unit in Britain:

The most important fossil you’ve never heard of

10 April 2017

It’s not a household name, but an ancient creature found in the Scottish borders fills a crucial period in the evolutionary record. It sheds light on how four-limbed creatures became established on land.

An ancient animal found in rocks from the Scottish borders is thought to be the earliest known example of an animal with a backbone to live on land.

The fossilised remains of this highly significant creature, called Tiny, shed light on a key period in our evolutionary history.

Tiny has four limbs, a pair of lungs and up to five fingers (the fossil evidence is unclear exactly how many).

“It was one small step for Tiny, one giant leap for vertebrates,” said palaeontologist Dr Nick Fraser in an interview on the BBC Radio 4’s Life Scientific.

“Without Tiny, there would be no birds, no dinosaurs, no crocodiles, no mammals, no lizards and obviously we wouldn’t be around.”

“So that one step is crucial”, Fraser said. “And this fossil is right here on our doorstep in the Scottish Borders.”

There are infuriatingly few fossils from this important period in our evolutionary history, known as Romer’s Gap.

Previously, some palaeontologists had argued that this gap in the fossil record was due to lower than average oxygen levels in the earth’s atmosphere.

But the recent discovery of several four-limbed creatures like Tiny suggests many terrestrial tetrapods were thriving on land about 360 million years ago.

The late Stan Wood, a field collector, spent several decades looking for fossils to fill Romer’s gap, convinced that it didn’t really exist. In the late 2000s, he began to uncover a number of important fossils near the Whiteadder river in East Lothian.

He phoned Nick Fraser, director of natural sciences at the National Museums in Scotland, to alert him.

Members of the Tw:eed Project then collected rocks from this area and analysed them using CT scans.

Many ancient tetrapods were the size of dogs. So, with a skull just 4cm long, this one was dubbed Tiny.

So why isn’t this important fossil better-known? Perhaps because it is so small.

Or perhaps because, to this day, Tiny remains trapped in a rock and hidden from view.

Fossil monkey blood discovery in Dominican Republic amber


This video from the USA says about itself:

25 July 2014

Nature and science documentarian David Attenborough describes the effort to screen a newly rediscovered collection of amber from the Dominican Republic and the tiny grasshopper found in 20-million-year-old amber that was named for him. Researchers at the Illinois Natural History Survey at the University of Illinois are scouring more than 160 pounds (72 kg) of the Dominican amber for ancient fossils. When their work is completed, they will have the largest unbiased amber fossil collection in the world. The most valuable specimens will be digitized and made freely available on a website. The amber was collected by INHS entomologist Milton Sanderson in the late 1950s. Sanderson died in 2012.

For more information about the pygmy locust discovery: here.

For more information about the researchers’ work on the amber collection: here.

From Oregon State University in the USA:

Monkey business produces rare preserved blood in amber fossils

April 3, 2017

Summary: Two monkeys grooming each other about 20-30 million years ago may have helped produce a remarkable new find – the first fossilized red blood cells from a mammal, preserved so perfectly in amber that they appear to have been prepared for display in a laboratory.

Two monkeys grooming each other about 20-30 million years ago may have helped produce a remarkable new find — the first fossilized red blood cells from a mammal, preserved so perfectly in amber that they appear to have been prepared for display in a laboratory.

The discovery, published in the Journal of Medical Entomology, also describes the only known fossils of a type of parasite that still exists today, Babesia microti, which infects the blood cells of humans and other animals.

Two small holes in the back of a blood-engorged tick, which allowed blood to ooze out just as the tick became stuck in tree sap that later fossilized into amber, provide a brief glimpse of life in a tropical jungle millions of years ago in what is now the Dominican Republic.

“These two tiny holes indicate that something picked a tick off the mammal it was feeding on, puncturing it in the process and dropping it immediately into tree sap,” said George Poinar, Jr., professor emeritus in the College of Science at Oregon State University, author of the study and an international expert on plant and animal life forms found preserved in amber.

“This would be consistent with the grooming behavior of monkeys that we know lived at that time in this region. The fossilized blood cells, infected with these parasites, are simply amazing in their detail. This discovery provides the only known fossils of Babesia-type pathogens.”

The fossil parasites add to the history of the Order Piroplasmida, of which the Babesiidae is one family. In humans, the parasite B. microti can cause babesiosis, a disease with symptoms that resemble malaria and can be fatal. A related parasite in cattle can cause Texas cattle fever, which has been a historic problem in the plains states, and just this spring is causing another outbreak that has led to quarantines on more than 500,000 acres of land in Texas.

“The life forms we find in amber can reveal so much about the history and evolution of diseases we still struggle with today,” Poinar said. “This parasite, for instance, was clearly around millions of years before humans, and appears to have evolved alongside primates, among other hosts.”

Part of what makes these fossils unique, Poinar said, is the clarity by which the parasites and blood cells are preserved, almost as if they had been stained and otherwise treated in a laboratory for inspection. The parasites were different enough in texture and density to stand out clearly within the red blood cells during the natural embalming process for which amber is famous.

See also here. And here.

A salamander found preserved in amber from the Dominican Republic is the first-ever fossil of its kind, and also shows that salamanders once lived in the Caribbean region, where they now are all extinct: here.

Ancient bed bug discovery in Oregon, USA


This video from the USA says about itself:

4 April 2017

Bedbugs have been making lives of other creatures miserable for a long time – scientists report that they have found the earliest known remains of bed bug relatives in a cave in southern Oregon.

From the Entomological Society of America:

Oldest remains of insects from bed bug genus found in Oregon

Specimens from genus Cimex date to nearly 11,000 years ago

April 4, 2017

Summary: A cave in Oregon that is the site of some the oldest preserved evidence of human activity in North America was also once home to not-too-distant cousins of the common bed bug. Archaeologists describe remains found in caves near Paisley, Ore., that represent the oldest specimens of insects from the genus Cimex ever found, ranging between 5,100 and 11,000 years old.

A cave in southern Oregon that is the site of some the oldest preserved evidence of human activity in North America was also once home to not-too-distant cousins of the common bed bug.

In research to be published next week in the Entomological Society of America’s Journal of Medical Entomology, a pair of archaeologists describe remains found in caves near Paisley, Oregon, that represent the oldest specimens of insects from the genus Cimex ever found, ranging between 5,100 and 11,000 years old.

The remains were identified as relatives of the bed bug, Cimex lectularius, but they were “not the bed bug we all know and love from hotel rooms,” says Martin E. Adams of Paleoinsect Research and co-author on the study with Dennis L. Jenkins of the Museum of Natural and Cultural History at the University of Oregon. The species in the Paisley Five Mile Point Caves (Cimex pilosellus, Cimex latipennis, and Cimex antennatus) are all parasites of bats.

Previously, the oldest remains of “cimicids” ever found were just 3,500 years old, found in Egypt in 1999, meaning the remains found at the Paisley Caves are the oldest Cimex specimens by a wide margin, and they raise some interesting questions for researchers about how cimicids have interacted (or not) with humans in the past.

Cimex lectularius and Cimex hemipterus are the two bed bug species that are known to parasitize humans, widely believed to have adapted to that role thousands of years ago when humans shared caves with bats in Europe, Asia, and Africa. The species found in the Oregon caves, however, never made that jump, and Adams says it’s unclear why not.

“Were the cimicid populations too small to establish themselves outside the caves, or were the host populations too small?” Adams says. “Given that Paisley Caves was only a seasonal occupation area for human hunter-gatherers, did the humans move around too much, or were the bugs not able to withstand the environment outside the caves for very long? Or, were there other constraints involved? I’m working on these last few archaeological questions right now.”

The identification of the three Cimex species may also offer some clues to climactic trends during the eras they were dated to, Adams says. Cimex antennatus, for instance, tends to favor the warmer climates of California and Nevada. “The presence of warm-tolerant cimicids in the caves, such as Cimex antennatus, may suggest that climatic conditions at Paisley Caves 5,100 years ago were similar to what Cimex antennatus enjoys today in its current range.”

Sea lily fossils discovery in World War I trenches


This 2015 video from the USA is called Everything About Crinoids

From Ohio State University in the USA:

Rock exposed in World War I trenches offers new fossil find

Sea lily ancestors spent youth hitchhiking around ancient oceans, discovery suggests

April 3, 2017

Summary: An unusual fossil find is giving scientists new ideas about how some of the earliest animals on Earth came to dominate the world’s oceans.

An international research team found 425-million-year-old fossilized remnants of juvenile crinoids, a distant ancestor of today’s sea lilies, encased in iron oxide and limestone in the Austrian Alps.

Researchers collected the rock from a formation on the border between Italy and Austria known as the Cardiola Formation, which was exposed in trenches dug during World War I.

Crinoids were abundant long ago, when they carpeted the sea floor. Most stalked crinoid fossils depict spindly, plantlike animals anchored to sea floor rocks, explained William Ausich, professor of earth sciences at The Ohio State University and co-author of the study in the open-access journal Geologica Acta.

Fossils of juvenile crinoids are rare, he said.

Rarer still is that these newly uncovered crinoids weren’t attached to rocks when they died. Whatever they were attached to during their young lives didn’t survive fossilization.

“The fossils indicate that they were either attached to objects floating in the water at the time, or attached to another bottom dweller that lacked preservable hard parts,” said Ausich said.

They might have clung to free-floating algae beds or swimming cephalopods, either of which could have carried them far away from where they formed as larvae.

Modern sea lilies reproduce by ejecting sperm and eggs into the water. Larvae grow into free-floating juvenile animals and eventually attach to the ocean bottom, where they grow to adulthood within 18 months.

At least, that’s what sea lilies do today. This fossil find suggests that their distant ancestors sometimes settled on objects that carried them far from home before they reached reproductive age.

“We now have important information about the behavior of these ancient organisms, and a clue as to why they had such a wide geographic distribution,” Ausich said.

With long, stem-like bodies topped with feathery fronds, crinoids resembled flowers, though the center of the “flower” was a mouth, and the “petals” were arms that captured plankton for food. At the other end of the creature was star-shaped organ called a holdfast, which gripped the seafloor.

While some of today’s sea lilies are able to detach their holdfasts from the seafloor and walk short distances on their arms, they don’t do it often. If their crinoid ancestors spent their entire adult lives similarly anchored to one spot, they couldn’t have spread worldwide without help.

Fossilized holdfasts are all that remain of the young crinoids uncovered in the Alps, and that’s not unusual, Ausich said.

“The hard part about studying the fossils that I study is that they need to be buried alive in order to be completely preserved,” he explained. “Crinoids and other echinoderms have a skeleton comprised of innumerable individual calcite plates held together by various connective soft tissues. These tissues begin to decompose within a day of an organism’s death.

“So, having only parts [of crinoids] rather than whole organisms is actually the norm — as frustrating as that may be.”

The sediment that eventually covered these young crinoids must have been rich in iron, because the holdfasts were preserved as minerals of iron oxide — and that detail is unusual, he added.

Today, the fossil holdfasts look like rusty star-shaped rings. The stars measure only 1 to 4 millimeters across, meaning they came from very young, post-larval juveniles.

The tiny fossils might have been hard to isolate from the surrounding rock, but researchers were able to take advantage of the presence of iron oxide to dissolve the limestone and pull the fossils from the resulting slurry with a magnet.

Researchers had actually collected rock samples from the Cardiola Formation long ago, Ausich said. The area contains abundant fossils, including ancient corals and trilobites. But only recently did anyone discover that these particular rock samples also contained the crinoid holdfasts.

Researchers are interested in crinoids not just because they’re part of Earth’s history, but because the various crinoid species were able to survive millions of years of climate changes to become the sea lilies we know today.

New tyrannosaur relative discovered


This video from the USA says about itself:

30 March 2017

Researchers from several American universities have finally given a name to a species of tyrannosaur dinosaur that was unearthed 25 years ago, helping build a clearer understanding of the T-rex family tree.

The new species, called Daspletosaurus horneri, was found in Montana and might have had sensitive facial skin.

From Carthage College in the USA:

New dinosaur species sheds light on evolution, provides facial makeover for tyrannosaurs

March 30, 2017

Summary: Scientists have discovered a new relative of T. rex that is the geologically youngest species of the lineage called Daspletosaurus, the ‘frightful lizards’. The new species of dinosaur, Daspletosaurus horneri, evolved directly from its geologically older relative, D. torosus. The excellently preserved fossils reveal that the face of tyrannosaurs was covered by a mask of large flat scales, with smaller patches of armor-like skin and sheaths of horn. The arrangement of scales suggests D. horneri had a crocodile-like pressure sensing snout.

An investigation by a team of scientists from Australia, Louisiana, Montana, New Mexico, and Wisconsin has identified and named a new species of the tyrannosaur clan: Daspletosaurus horneri — “Horner’s Frightful Lizard.”

The species is named for renowned dinosaur paleontologist John “Jack” R. Horner, formerly curator at the Museum of the Rockies (MOR) in Bozeman, Montana. The tyrannosaur‘s name honors his discoveries of numerous dinosaur fossils and his mentorship of so many students that launched them to accomplished scientific careers. The type (name-bearing) specimens are stored in the research collections of the MOR.

The research is led by Thomas Carr, a professor in Carthage College’s Biology Department and an expert on the evolution and growth of Tyrannosaurus rex and its closest relatives, collectively called tyrannosaurs.

The fossil resources of Montana, where the new tyrannosaur was found, are central to studies of dinosaur evolution, explains Professor David Varricchio of Montana State University: “These specimens emphasize the excellent record of dinosaurs to be found in Montana. They highlight both the quality of the specimens, the preservation revealing the details of how these giant carnivores once looked in life, as well as the overall collection of specimens that provides insight into the evolution of the tyrannosaur group. Montana remains a wonderful place to explore the Cretaceous.”

In addition to adding a new species to the tyrannosaur family tree, the team’s research provides new information about the mode of evolution and life appearance of tyrannosaurs — specifically the face. This latest study, published today in Nature Publishing Group’s Scientific Reports, found evidence for a rare, nonbranching type of evolution in tyrannosaurs and that tyrannosaurs had scaly, lipless faces and a highly touch-sensitive snout.

Carr said: “Daspletosaurus horneri was the youngest, and last, of its lineage that lived after its closest relative, D. torosus, which is found in Alberta, Canada. The close evolutionary relationship between the species taken with their geographic proximity and their sequential occurrence suggests that together they represent a single lineage that changed over geological time, where D. torosus has morphed into D. horneri.”

Jason Moore, a professor in the Honors College at the University of New Mexico, elaborated: “One of the difficulties in demonstrating anagenetic change, as we suggest occurred in the Daspletosaurus lineage, is establishing that the different species in question don’t overlap in time. The new radiometric dates we measured from the Two Medicine Formation not only help support that D. torosus and D. horneri did not live at the same time, but also help us refine the timeline of environmental and ecological changes recorded by the Two Medicine Formation.”

Eric Roberts, a professor in geosciences with the College of Science and Engineering at James Cook University, explained: “Advances in radioisotopic dating of sedimentary deposits is key to testing this and many other evolutionary and ecological questions about dinosaurs and other ancient organisms. New age dates presented in this study are just the tip of the iceberg. Ongoing work in this field will provide unprecedented improvements in the dating of Late Cretaceous dinosaurs from western North America over the next few years.”

Continued Carr, “When we consider the geological ages of the two species, the evolution of Daspletosaurus gives us an indication of how slowly evolution can act on large dinosaurs, which in this case happened over a span of 2.3 million years.

“This type of speciation is called anagenesis, which is different from the more common type called cladogensis, where an ancestral species splits into two or more descendant species. Although uncommon in many evolutionary studies, anagenesis has been reported in some duck-billed dinosaurs and horned dinosaurs. Daspletosaurus and these other dinosaurs point the way forward in picking out the evidence for anagenesis in the fossil record.”

The team’s work literally changes the face of tyrannosaurs, which they found was covered by a lipless “mask” of large flat scales and extensive patches of armor-like skin. This conclusion results from comparison of tyrannosaur skulls with those of crocodilians, birds, and mammals, and earlier work by other researchers who had matched bone texture with different types of skin covering.

Jayc Sedlmayr, a professor at the Louisiana State University Health Sciences Center New Orleans, explained, “Much of our research went beyond field paleontology: it was generated from lab based comparative anatomy, where you get arms deep in “blood and guts” dissecting birds as living dinosaurs and crocodilians as their closest living relatives and based on the similarities of the facial nerves and arteries we found in those same groups that left a trace on the bones, we were able to then reconstruct them in the new tyrannosaur species.”

“It turns out that tyrannosaurs are identical to crocodilians in that the bones of their snouts and jaws are rough, except for a narrow band of smooth bone along the tooth row. In crocodilians, the rough texture occurs deep to large flat scales; given the identical texture, tyrannosaurs had the same covering,” explained Carr. “We did not find any evidence for lips in tyrannosaurs: the rough texture covered by scales extends nearly to the tooth row, providing no space for lips.

“However, we did find evidence for other types of skin on the face, including areas of extremely coarse bone that supported armor-like skin on the snout and on the sides of the lower jaws. The armor-like skin would have protected tyrannosaurs from abrasions, perhaps sustained when hunting and feeding.”

“Strikingly, the large horn behind the eye is elevated beyond the side of the head, indicating a covering of keratin, the hard and shiny material that makes up human fingernails,” he continued.

In crocodilians and tyrannosaurs, the snout and jaws are penetrated by numerous small nerve openings, allowing hundreds of branches of the trigeminal nerve to innervate the skin, producing a sensitivity that, in crocodilians, is as sensitive as human fingertips. “Given that the foramina are identical in tyrannosaurs indicates that they had super-sensitive skin as well,” explained Carr.

This sensitivity is part of a bigger evolutionary story, explained Sedlmayr. “Our findings of a complex sensory web is especially interesting because it is derived from the trigeminal nerve, which has an extraordinary evolutionary history of developing into wildly different ‘sixth senses’ in different vertebrates, such as sensing magnetic fields for bird migration, electroreception for predation in the platypus bill or the whisker pits of dolphins, sensing infrared in pit vipers to identify prey, guiding movements in mammals through the use of whiskers, sensing vibrations through the water by alligators, and turning the elephant trunk into a sensitive ‘hand’ similar to what has been done to the entire face of tyrannosaurs.”