Ankylosaur dinosaur discovery in Utah, USA


This video from the USA says about itself:

19 July 2018

Akainacephalus johnsoni, a new species of ankylosaurid dinosaur never before described in scientific literature, is introduced by paleontologists Jell Wiersma, PhD candidate at James Cook University, and Randall Iris, chief curator at the Natural History Museum of Utah. The new species was discovered in 2008 by Scott Richardson, a paleontologist with the BLM, during an expedition to the Kaiparowits Formation in Grand Staircase-Escalante National Monument. For years, scientists and volunteers have been preparing and studying the fossil at the Natural History Museum of Utah, where it is now permanently housed. A mounted skeleton of Akainacephalus johnsoni is on display in the Past Worlds exhibit at the museum in Salt Lake City.

From the University of Utah in the USA:

Newly discovered armored dinosaur from Utah reveals intriguing family history

Spikey southwestern species evolved from Asian ancestors

July 19, 2018

Fossils of a new genus and species of an ankylosaurid dinosaurAkainacephalus johnsoni — have been unearthed in the Kaiparowits Formation of Grand Staircase-Escalante National Monument (GSENM), in Kane County, southern Utah, U.S.A., and are revealing new details about the diversity and evolution of this group of armored dinosaurs. Expected to look like other North American Late Cretaceous ankylosaurid dinosaurs with smooth bony armor on the skull, the new research suggests just the opposite and indicates that the defining features of Akainacephalus, specifically the spiky bony armor covering the skull and snout, align more closely with Asian ankylosaurids, who also have more pronounced spikes covering their skulls.

Akainacephalus was announced today in the open-access scientific journal PeerJ and unveiled on exhibit in the Past Worlds Gallery of the Natural History Museum of Utah at the Rio Tinto Center in Salt Lake City, Utah. The genus name is derived from the Greek words akaina, which means ‘thorn’ or ‘spike’, and cephalus, meaning ‘head’. The species epithet johnsoni honors Randy Johnson, a dedicated museum volunteer who skillfully prepared its skull. Other talented volunteers helped to prepare the rest of the specimen.

“I’m a retired chemist, but I’ve always been interested in most of the science disciplines. I never thought that I would have the opportunity to actually work on fossils that could be important for paleontologists”, said Randy Johnson. “Now that I’m a museum volunteer, I’m getting the opportunity to work on a large variety of fossils and consult with top paleontologists — it’s like a dream second career. I couldn’t believe it when they told me they are naming the ankylosaur after me, a once in a lifetime honor”, said Johnson.

Ankylosaurids are a group of four-legged herbivorous armored dinosaurs with imposing bony tail clubs. Though ankylosaurids originated in Asia between 125 — 100 million years ago, they do not appear in the western North American fossil record until ~77 million years ago. The new species Akainacephalus lived 76 million years ago during the Late Cretaceous Period and offers the most complete skeleton of an ankylosaurid dinosaur found in the southwestern US. It includes a complete skull, much of the vertebral column, including a complete tail club, several fore and hind limbs elements, and bony body armor that includes two neck rings and spiked armor plates.

The unique arrangement of bony armor in the shape of small cones and pyramids covering the snout and head is the key research finding indicating that Akainacephalus is closely related to the New Mexican ankylosaurid Nodocephalosaurus kirtlandensis. Surprisingly, Akainacephalus and Nodocephalosaurus are more closely related to Asian ankylosaurids such as Saichania and Tarchia than to other Late Cretaceous North American ankylosaurids, including Ankylosaurus and Euoplocephalus. Both of the latter taxa possess flat skull armor.

“A reasonable hypothesis would be that ankylosaurids from Utah are related to those found elsewhere in western North America, so we were really surprised to discover that Akainacephalus was so closely related to species from Asia”, remarked Randall Irmis, co-author of the study.

Though ankylosaurids originated in Asia between 125 — 100 million years ago, they do not appear in the North American fossil record until around 77 million years ago. Akainacephalus once roamed the southern part of Laramidia, a landmass on the western coast of a shallow sea that flooded the central region, splitting the continent of North America in two. This caused isolation along western and eastern portions of the North American continent during the Late Cretaceous Period, between 95-70 million years ago.

Lead author Jelle Wiersma suggests that the geographic distribution of Late Cretaceous ankylosaurids throughout the Western Interior was the result of several geologically brief intervals of lowered sea level that allowed Asian ankylosaurid dinosaurs to immigrate to North America several times during the Late Cretaceous, resulting in the presence of two separate groups of ankylosaurid dinosaurs. This lowering of sea levels exposed the Beringian land bridge, allowing dinosaurs and other animals to move between Asia and North America.

“It is always exciting to name a new fossil taxon, but it is equally exciting if that taxon also provides additional insights into the bigger picture of its life, such as its diet or aspects of its behavior, and the environment it lived in”, said Wiersma. “Such is exactly the case with Akainacephalus johnsoni; not only is this the first described and named Late Cretaceous ankylosaurid dinosaur from Utah, but this unique animal also strengthens the evidence that distinct northern and southern provincialism existed during the late Campanian stage in Laramidia, because to date, we don’t see this type of ankylosaurid dinosaurs in the fossil record of northern Laramidia”, he said.

Wiersma explained that additionally, together with its close relative Nodocephalosaurus from New Mexico, Akainacephalus looks very different compared to other North American ankylosaurids such as Ankylosaurus, but instead, look much more like Asian ankylosaurids including Saichania and Tarchia. From these observations we can conclude that at least two immigration events took place during Late Cretaceous times when lowered sea levels exposed the Beringian land bridge, connecting Asia with western North America.

Ankylosaurid dinosaurs, among many other groups of animals, eventually crossed this land bridge, emigrating from Asia into western North America, resulting into two different types of Late Cretaceous ankylosaurid dinosaurs: ones that evolved flatter skull armor like Ankylosaurus and Euoplocephalus, and ones possessing very spiky skull armor such as Akainacephalus and Nodocephalosaurus.

“It is extremely fascinating and important for the science of paleontology that we can read so much information from the fossil record, allowing us to better understand extinct organisms and the ecosystems they were a part of”, concluded Wiersma.

These new findings are part of a study funded in large part by the Bureau of Land Management, as well as the Geological Society of America, and a University of Utah Department of Geology & Geophysics Graduate Student Grant. The project was led by University of Utah M.Sc. student Jelle Wiersma, now a Ph.D. student in the Dept. of Geosciences at James Cook University, Queensland, Australia. Wiersma was advised by co-author Dr. Randall Irmis, chief curator and curator of paleontology at the Natural History Museum of Utah, and associate professor in the Dept. of Geology and Geophysics, University of Utah.

Anklysaurid Dinosaurs on the Lost Continent of Southern Laramidia

Akainacephalus johnsoni was discovered in Grand Staircase-Escalante National Monument (GSENM) which encompasses a large area of high desert terrain in south-central Utah. This vast and rugged region, part of the National Landscape Conservation System administered by the Bureau of Land Management (BLM), was the last major area in the lower 48 states to be formally mapped by cartographers.

During the Late Cretaceous, GSENM was in the southern portion of Laramidia, which stretched from the Arctic Circle to the Gulf of Mexico. Akainacephalus is part of a growing number of new dinosaur discoveries over the past 15 years demonstrating the incredible diversity of animals and plants living on Laramidia between 80-75 million years ago. One of the most exciting conclusions from this work is that nearly every species of dinosaur discovered in GSENM is new to science, and Akainacephalus is no exception. Other recently discovered species include large and small meat-eating dinosaurs (e.g., tyrannosaurs), horned dinosaurs, and duck-billed dinosaurs. “A major long-term goal of our work in southern Utah is to try and understand why the species in GSENM differ from relatives of the same geologic age found in other parts of Laramidia”, said Wiersma. Hypotheses for the differences include changes in sea level, climate differences across latitude, and physical barriers to animal movement such as mountains and large rivers.

Fact Sheet: Major Points of the Paper

(1) Akainacephalus is a remarkable new species of ankylosaurid dinosaur from the upper Campanian Kaiparowits Formation in Grand Staircase-Escalante National Monument in Kane County, southern Utah.

(2) Akainacephalus is the most complete Late Cretaceous ankylosaurid dinosaur discovered from Utah and the southwestern U.S., and is distinguished by a number of unique features, including spikes and cones of the bony exterior covering the head and snout.

(3) The spikes and cones of bony armor on the skull of Akainacephalus are similar to those found on the New Mexican ankylosaurid Nodocephelausaurus kirtlandensis but distinct from all other known Late Cretaceous Laramidian ankylosaurids such as Ankylosaurus, Euoplocephalus, and Ziapelta, indicating these two species are more closely related to some Asian ankylosaurids.

(4) The new ankylosaurid Akainacephalus suggests multiple ankylosaurid emigration events from Asia to Laramidia during the Late Cretaceous.

(5) Together with some anklylosaurid dinosaurs from northern Laramidia, including Dyoplosaurus acutosquameus and Scolosaurus cutleri (both ~ 77 Ma), Akainacephalus represents one of the oldest known ankylosaurid dinosaurs from the Late Cretaceous of western North America (~76 Ma).

New Dinosaur Name: Akainacephalus johnsoni

  • The first part of the name, Akaina, is a Greek word that can be translated to spike or thorn. The second part of the name cephalus means head, and the epithet johnsoni honors Randy Johnson, a dedicated paleontology volunteer at the Natural History Museum of Utah who prepared the specimen’s skull.

Size

  • Akainacephalus, is a medium-sized dinosaur, and was 13-16 feet long (4-5 meters) and was 3 ½ feet tall (1 — 1.5 meters) at the hips.

Relationships

  • Akainacephalus belongs to a group of herbivorous armored dinosaurs called anklosaurids that lived in Asia and western North America during the Late Cretaceous Period (100-66 million years ago). One of the unique features of ankylosaurid dinosaurs is the presence of a characteristic bony tail club.

Anatomy

  • Akainacephalus walked on four legs, which were positioned directly underneath his body.
  • Akainacephalus was covered in bony armor from head to tail, with various sized and shaped bony plates, called osteoderms, which are thought to provide protection.
  • Akainacephalus is characterized by its elaborate covering of spikes and horns on the skull, as well a large bony club at the end of its tail.
  • Akainacephalus presumably had small, leaf-shaped teeth for eating plants. These fell out of the jaw after death, but before the skeleton was buried by sediment.

Age and Geography

  • Akainacephalus lived during the upper Campanian stage of the Late Cretaceous Period, which spanned from approximately 84 million to 72 million years ago. This animal lived about 76 million years ago.
  • Akainacephalus was discovered in 76 Ma old rocks of the Kaiparowits Formation, a geological/stratigraphic unit exposed in southern Utah consisting of sedimentary rocks deposited by rivers and streams.

Discovery & Excavation

  • Akainacephalus was first discovered in 2008 during a museum-led paleontological expedition in a remote area of BLM-administered Grand Staircase-Escalante National Monument (GSENM) in Kane County, southern Utah, USA. The site was discovered by BLM employee Scott Richardson.
  • The bones of Akainacephalus that were discovered include a complete skull, bony armor that includes neck rings and spiked plates, many vertebrae, forelimb and hindlimb bones, and a near complete tail with tail club.
  • Akainacephalus was found together with skeletons of several other animals at the same site, including a duck-bill dinosaur (Gryposaurus), a recently-described species of turtle (Arvinachelys), and a yet unnamed relative of alligators and caimans).
  • Akainacephalus is permanently housed in the collections of the Natural History Museum of Utah at the Rio Tinto Center in Salt Lake City and on public display at the museum’s Past Worlds exhibit.
  • These discoveries are the result of an ongoing collaboration between the Natural History Museum of Utah and the Bureau of Land Management.

Preparation

  • It required almost four years to fully prepare all of the bones of Akainacephalus.
  • Preparation of the skull was done by museum volunteer Randy Johnson, who is honored in the new name, Akainacephalus johnsoni
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Mosasaur fossils, new study


This 2015 video says about itself:

With six-foot jaws and a nasty disposition, the Mosasaur dined on giant sharks and Plesiosaurs. An extra set of teeth on the roof of its mouth guaranteed that when it sunk its teeth into something, the only way for it to go was down its gullet.

Giant beasts that’ve been long extinct and the different world they once inhabited are resurrected through fossil evidence and other scientific data. This documentary reveals how these creatures once lived and flourished.

By the University of Bristol in England:

Missing bones and our understanding of ancient biodiversity

July 16, 2018

Fossils come in many shapes and sizes, ranging from isolated fragments of bones and teeth to complete skeletons.

Palaeontologists face an important question, ‘does the quality of fossil skeletons impact our understanding of biodiversity patterns in the past’.

Palaeontologists rely on the fossil record to uncover the hidden pasts of long extinct animal groups.

When fossil specimens are discovered, new species are often named, and over time, we begin to paint a picture of past biodiversity.

However, scientific practises vary, some new species are named from poor material, such as single fragments of bone and teeth, while other species are known from many complete, or partially complete, skeletons.

Could it be that our understanding of past biodiversity is simply related to the quality of fossil material in different geological rock formations through time? This question relates to a fundamental debate within palaeontology about the quality and trustworthiness of the fossil record.

In a new paper, researchers from the Universities of Bristol and Leeds analysed fossil specimen quality and tested its relationship with past diversity.

The focus of the study is an ancient group of ocean-going reptiles called mosasaurs.

Mosasaurs were a diverse group of large predatory animals, many were over 15 metres long. Scientists believe that mosasaurs were closely related to snakes and lizards, and they apparently became very diverse in the Late Cretaceous, before disappearing 66 million years ago.

Lead author Dr Dan Driscoll, a Research Associate at the University of Bristol and former MSc Palaeobiology student, said: “Mosasaurs have one of the richest vertebrate fossil records and have attracted study for over two centuries.

“The first mosasaur described was in 1808! Often, studies of fossil record quality have focussed simply on the numbers of fossil species, however, it is important to consider the completeness of individual fossil specimens, and whether this distorts our view of diversity. To do this, robust statistical analysis is required.”

The authors examined over 4,000 mosasaur fossil specimens and scored them for the degree of completeness in the largest study of its kind.

Using mathematical modelling approaches they show that fossil completeness does not bias the fossil record of mosasaurs and that the rich fossil record of mosasaurs provides an accurate picture of their diversity and evolutionary history.

Co-author Dr Tom Stubbs added: “Mosasaurs were key players in Late Cretaceous marine ecosystems. Our study confirms that mosasaurs were a successful group of animals that continued to diversify through their evolutionary history, before being abruptly wiped out by the extinction event that also impacted dinosaurs and many other groups.”

Co-author Dr Alex Dunhill, from the School of Earth and Environment at the University of Leeds, said: “Palaeontologists often presume that the vertebrate fossil record is heavily biased by sampling. This may be so but, here we show that variation in the completeness of fossil specimens does not appear to bias large scale evolutionary patterns.”

The revelations provided by this new study provide new insights into the evolution of mosasaurs, and highlight that, although the fossil record is undeniably incomplete, variable fossil completeness does not appear to bias large scale evolutionary and ecological patterns.

Tyrannosaurus rex’s short arms, why?


This 26 June 2018 video says about itself:

Tyrannosaurus rex was big, Tyrannosaurus rex was vicious, and Tyrannosaurus rex had tiny arms. The story of how T-Rex lost its arms is, itself, pretty simple. But the story of why it kept those little limbs, and how it used them? Well, that’s a little more complicated.

Dinosaur age and modern frog discoveries


This 14 June 2018 video says about itself:

Frogs trapped in amber for 99 million years are giving a glimpse of a lost world. The tiny creatures have been preserved in sticky tree resin from the later part of the Age of the Dinosaurs.

From the Florida Museum of Natural History in the USA:

Amber fossils provide oldest evidence of frogs in wet, tropical forests

June 14, 2018

Summary: 99-million-year-old amber fossils from Myanmar provide the earliest evidence of frogs in wet, tropical forests.

About 99 million years ago, a tiny juvenile frog in present-day Myanmar was suddenly trapped in sap with a beetle, perhaps its intended next meal.

Unlucky for the frog, but lucky for science.

An extinct species now named Electrorana limoae, it’s one of four fossils that provide the earliest direct evidence of frogs living in wet, tropical forests and are the oldest-known examples of frogs preserved in amber.

“It’s almost unheard of to get a fossil frog from this time period that is small, has preservation of small bones and is mostly three-dimensional. This is pretty special,” said David Blackburn, study co-author and the associate curator of herpetology at the Florida Museum of Natural History. “But what’s most exciting about this animal is its context. These frogs were part of a tropical ecosystem that, in some ways, might not have been that different to what we find today — minus the dinosaurs.”

The findings and species description were published today in Nature’s Scientific Reports.

Frogs have been around for at least 200 million years, but glimpsing their early heyday is tough. Often small and lightly built, frogs don’t tend to preserve well. The frog fossil record skews toward more robust species from arid, seasonal environments, although the bulk of frog diversity today lives in tropical forests.

“Ask any kid what lives in a rainforest, and frogs are on the list”, Blackburn said. “But surprisingly, we have almost nothing from the fossil record to say that’s a longstanding association.”

The amber deposits of northern Myanmar in Southeast Asia provide a unique record of ancient forest ecosystems, with fossil evidence of mosses, bamboo-like plants, aquatic spiders and velvet worms. The discovery of Electrorana and the other fossils, the first frogs to be recovered from these deposits, help add to our understanding of frogs in the Cretaceous period, showing they have inhabited wet, tropical forests for at least 99 million years.

Frogs in amber are quite rare, with previous examples found in the Dominican Republic and Mexico and dating back only about 40 million and 25 million years, respectively.

Less than an inch long, Electrorana is the most well-preserved of the group. Clearly visible in the amber are the frog’s skull, its forelimbs, part of its backbone, a partial hind limb and the unidentified beetle. The other amber fossils contain two hands and an imprint of a frog that likely decayed inside the resin.

But Electrorana raises more questions than it answers, Blackburn said.

Many characteristics herpetologists use to discern details of a frog’s life history and determine how it’s related to other frogs — wrist bones, the pelvis, hip bones, the inner ear, the top of the backbone — are either missing or were not yet fully developed in the juvenile frog.

The existing bones provide clues about Electrorana’s possible living relatives, Blackburn said, but the results are puzzling: Species that have similar features include fire-bellied toads and midwife toads — Eurasian species that live in temperate, not tropical, ecosystems.

Gathering CT skeletal data for both living and extinct frogs, one of Blackburn’s long-term projects, could help illuminate ancient evolutionary relationships, possibly clarifying how Electrorana fits into the frog tree of life.

In the meantime, Blackburn nurtures the hope that other frogs in amber will be discovered, making Electrorana more than a one-hit wonder.

“We don’t have a lot of single-species frog communities in forests. It seems extremely unlikely that there’s only one. There could be a lot more fossils coming.”

In a new study, researchers have investigated how the endocrine-disrupting substance linuron affects reproduction in the West African clawed frog, Xenopus tropicalis. The scientists found that linuron, which is used as a pesticicide, impaired the males’ fertility, and that tadpoles developed ovaries instead of testicles to a greater extent, which caused a female-biased sex ratio: here.

Dinosaur age tick in spider web preserved in amber


This 2014 video is called Spider webbing up a tick.

And now, all the way back from 2014 to the age of dinosaurs

From the University of Kansas in the USA:

For 100 million years, amber freezes a tableau of tick‘s worst day ever

June 13, 2018

Summary: This is the first time this kind of interaction between ticks and spiders has been documented in the fossil record. Even though ticks aren’t a typical staple of spider diets, spiders can occasionally prey on ticks in modern ecosystems.

One day in Myanmar during the Cretaceous period, a tick managed to ensnare itself in a spider web. Realizing its predicament, the tick struggled to get free. But the spider that built the web was having none of it. The spider popped over to the doomed tick and quickly wrapped it up in silk, immobilizing it for eternity.

We know the outline of this primordial worst-day-ever because the silk-wrapped tick subsequently was entombed in amber that may have dripped from a nearby tree. Its fate, literally, was sealed.

Fast-forward 100 million years or so, and that same tick was discovered by a German collector named Patrick Müller who was searching in Myanmar for Burmese amber pieces of scientific value. He passed the discovery on to scientist Jason Dunlop at the Museum für Naturkunde in Berlin, who realized it was an important specimen.

“Dunlop brought in Lidia Chitimia-Dobler, who is a tick expert at the Bundeswehr Institute of Microbiology, and myself because we’ve worked together on Burmese amber things,” said Paul Selden, distinguished professor of geology at the University of Kansas and director of the Paleontological Institute at the KU Biodiversity Institute and Natural History Museum.

Together with microscopy expert Timo Pfeffer, the team has just published a description of the tick in the journal Cretaceous Research.

“It’s a show of behavior, really,” said Selden. “Ticks already are known from the Burmese amber — but it’s unusual to find one wrapped in spider silk. We’re not sure if the spider wrapped it in order to eat it later or if it was to get it out of the way and stop it from wriggling and destroying its web. That’s something spiders do.”

Selden said ticks are seldom found in Burmese amber, though the few that have been discovered were proved to be among the oldest tick specimens known to science.

“They’re rare because ticks don’t crawl around on tree trunks,” he said. “Amber is tree resin, so it tends to capture things that crawl around on bark or the base of the tree. But ticks tend to be on long grass or bushes, waiting for passing animals to brush up against them, though some of them can be on birds or squirrels, or maybe a little crawling dinosaur.”

The researchers took pains to ensure the ancient tick was indeed bound in spider silk, rather than fungal filaments that sometimes can grow around a dead tick.

“We think this was spider silk because of the angles that the threads make,” Selden said. “Also, in the paper, we show a picture of a tick that started to decay — and the fungus on that tick grows from its orifices — from the inside to the outside. Whereas these threads are wrapped around externally and not concentrated at the orifices.”

According to the research team, this is the first time this kind of interaction between ticks and spiders has been documented in the fossil record. Even though ticks aren’t a typical staple of spider diets, spiders can occasionally prey on ticks in modern ecosystems.

“Just last year, I was on a field trip in Estonia and took a photo of a Steatoda spider wrapping up a red spider mite“, said Selden. “That was serendipitous.”

The KU researcher and his colleagues are unable to determine the species of spider that wrapped the tick because families of spiders known to catch ticks today lack a convincing Mesozoic fossil record. While it’s difficult to identify the producer of the fossil silk with any certainty, it’s safe to assume the spider’s behavior was characteristic of most known spiders in the forest today.

“We don’t know what kind of spider this was”, Selden said. “A spider’s web is stretched between twigs to catch prey that flies or bumps or crawls into it. As prey gets stuck, it adheres to the web and starts to struggle. Maybe some things can escape after some struggle, so the spider rushes to it out from hiding and wraps it in swaths of silk to immobilize it, to stop it escaping or destroying the web. This prevents prey from hitting back — stinging or biting — once it’s wrapped in silk it can’t move, and then the spider can bite it and inject gastric fluid to eat it or venom to subdue it as well.”

The amber that preserved the small drama occurring between the spider and tick from 100 million years ago offers a thought-provoking peek into the natural past, according to Selden.

“It’s really just an interesting little story — a piece of frozen behavior and an interaction between two organisms,” he said. “Rather than being the oldest thing or the biggest thing, it’s nice to be able to preserve some animal interaction and show it was a living ecosystem.”

Brazil’s oldest mammal named after David Bowie


This 29 May 2018 video, in Portuguese, is about the newly discovered dinosaur age mammal Brasilestes stardusti from Brazil.

From the Fundação de Amparo à Pesquisa do Estado de São Paulo in Brazil:

Discovery of the oldest mammal in Brazil pays tribute to David Bowie

June 11, 2018

Summary: Brasilestes stardusti lived around 70 million years ago and was named after Ziggy Stardust, the singer’s iconic persona. Description was based on a fossilized tooth. It’s the 1st indication that placental mammals and dinosaurs co-existed in South America. For scientists, fossil features showed similarities with another pre-historic mammal found in India, suggesting both shared a common ancestral native from the Gondwana supercontinent.

Brasilestes stardusti is the name given to the oldest known mammal found in Brazil. It lived in what is now the northwest of São Paulo State at the end of the Mesozoic Era between 87 million and 70 million years ago. It is the only Brazilian mammal known to have coexisted with the dinosaurs.

The discovery of Brasilestes was announced on May 30, 2018, by a team led by Max Langer, a professor at the University of São Paulo’s Ribeirão Preto School of Philosophy, Science & Letters (FFCLRP-USP). Langer’s team included colleagues at the Federal University of Goiás and the University of Campinas in Brazil, La Plata Museum in Argentina, and the Massachusetts Institute of Technology (MIT) in the US.

Physically speaking, Brasilestes consists of a fossilized premolar tooth with a maximum crown length of 3.5 mm. “The tooth is small and incomplete: the roots are missing,” said paleontologist Mariela Cordeiro de Castro, first author of the paper recently published in Royal Society Open Science.

“Small but not tiny”, Castro continued. “Although it’s only 3.5 mm, the Brasilestes tooth is three times bigger than all known Mesozoic mammal teeth. In the age of the dinosaurs, most mammals were the size of mice. Brasilestes was far larger, about the size of an opossum.”

The name of the new species pays tribute to British rock star David Bowie, who died in January 2016, a month after the fossil was found. Brasilestes stardusti alludes to Ziggy Stardust, an extraterrestrial character created by Bowie for a 1972 album.

The research was supported by the São Paulo Research Foundation — FAPESP as part of the thematic project “The origin and rise of dinosaurs in Gondwana (late Triassic-early Jurassic)”, for which Langer is principal investigator.

The fossilized tooth was found in a rocky outcrop of the Adamantina Formation in General Salgado, São Paulo State. The rocks are in a field on a ranch called Fazenda Buriti.

“We were visiting Mesozoic outcrops when Júlio Marsola [another member of the team], keen-sighted as a lynx, spotted a small tooth sticking up out of a rock”, said Castro, a professor at the Federal University of Goiás (UFG).

“The General Salgado deposits are well-known. Several Mesozoic crocodiles have come from them. The particular outcrop where I found Brasilestes is interesting, with dozens of fragments of Mesozoic crocodile eggshells. I bent down to look more closely at a small part of the outcrop to see if there were any eggshells and spotted the tooth. If it had stayed out in the open like that for a few more days, the rain would have swept it away.

“When I noticed what appeared to resemble the base of the tooth’s two roots [the roots themselves have broken off], I thought it must be a mammal. Laboratory analysis gave us the certainty that it is indeed from a mammal.”

A placental mammal in the Botucatu Desert

While a mere 3.5 mm tooth, especially an incomplete one, may seem insufficient to describe a new species of mammal, in actual, fact extinct mammals are frequently described on the basis of a single fossilized tooth.

This is because teeth are the most durable part of the mammalian skeleton. After all, they have to withstand the wear and tear of chewing for an entire lifetime. In contrast, many fish species and reptiles, for example, grow new teeth continually throughout their lives. Indeed, mammalian teeth are often the only skeletal remains that stay intact long enough to become fossilized.

The fact that a single premolar is all that is left of Brasilestes and that it is incomplete prevented the researchers from distinguishing with absolute confidence the group of mammals to which the species belonged. They know the tooth belonged to a therian, a member of a large subclass of Mammalia that includes marsupials and placentals.

Although there is not enough evidence to support the inclusion of Brasilestes in either infraclass, the researchers believe (but cannot categorically conclude) it was a placental mammal. If so, the fossil is unique.

Today, there are three major groups of mammals, namely, placentals, marsupials and monotremes. All three evolved during the Mesozoic Era. At that time, however, they were by no means the only groups of mammals. There were also multituberculates, which were common in the northern hemisphere, as well as groups typical of the southern hemisphere such as meridiolestids and gondwanatherians — named for Gondwana, the ancient southern supercontinent that gave rise to Africa, South America, Australia, Antarctica, and India.

The first Mesozoic mammal fossils were found in Argentinian Patagonia in the early 1980s, and some 30 species are now known. Until the Brasilestes announcement, these were the only ones found in South America. None remotely resembles the little tooth found in Brazil.

“When I showed the Brasilestes fossil to Edgardo Ortiz-Jaureguizar, a paleontologist at La Plata Museum, he was very surprised. He said he’d never seen anything like it, and at once showed it to another specialist at the same institution, Francisco Goin, who had the same reaction. Goin said Brasilestes resembled no other Mesozoic mammal found in Argentina, hence in South America”, Castro recalled.

Among the 30-odd Argentinian species of Mesozoic mammals, there are meridiolestids, gondwanatherians, and even a few suspected multituberculates. There are no marsupials or placentals. The only fossils in these two groups found in South America date from after the mass extinction that wiped out the dinosaurs 66 million years ago in an event that marks the end of the Mesozoic and the onset of the current geological era, the Cenozoic.

Until the discovery of Brasilestes, the only traces of Mesozoic mammals in Brazil were hundreds of tracks and footprints left by unknown creatures 130 million years ago as they traversed the dunes of the Botucatu Desert in what is now São Paulo State. The solidified surface of those dunes has been preserved as sandstone slabs on which the footprints can be seen.

In 1993, Reinaldo José Bertini , a professor at São Paulo State University (UNESP) in Rio Claro, announced the discovery of a mammalian jawbone fragment with a single tooth far smaller than the Brasilestes premolar. However, Bertini did not publish a detailed study of the fossil and therefore could not name a new species.

“Brasilestes is not just the first Brazilian Mesozoic mammal to be described but also one of the few Mesozoic mammals found in more central regions of South America. The Argentinian fossils were found in geological formations in Patagonia, the southern tip of the continent”, Langer said.

“Furthermore, Brasilestes is different from everything found before, suggesting that possibly placental mammals inhabited South America between 87.8 million and 70 million years ago,” said the FAPESP thematic project coordinator.

New species possibly related to a mammal from India

Even more surprisingly, the Mesozoic mammal with premolars that most resemble the Brasilestes tooth lived on the other side of the world, in India, between 70 million and 66 million years ago. Its name is Deccanolestes. No other creature in the global fossil record is so similar to Brasilestes.

How could two members of the same lineage have lived so far apart in unconnected regions? Approximately 100 million years ago, when South America and Africa had only just been separated by the opening of the South Atlantic, India was breaking away from Gondwana and starting to wander through the Indian Ocean.

This implies that at least 100 million years ago, the ancestors of Brasilestes and Deccanolestes populated the Gondwana supercontinent. In other words, the lineage to which Brasilestes and Deccanolestes belong is far older than the ages of their fossils — between 87 million and 70 million years ago for Brasilestes, and between 70 million and 66 million for Deccanolestes.

“The discovery of Brasilestes raises many more questions than answers about the biogeography of South American Mesozoic mammals”, Langer said. “Thanks to Brasilestes, we’ve realized that the history of Gondwana’s mammals is more complex than we thought.”

Finding triggers speculation on xenarthrans’ origins

This could give rise to new hypotheses and new lines of investigation. Who knows, for example, whether future research inspired by the discovery of Brasilestes will reveal the origin of a typical South American group, the xenarthrans, the order of armadillos, anteaters and sloths? Castro’s main research interest, in fact, is the evolutionary history of the xenarthrans.

“An interesting feature of the Brasilestes premolar is its superthin enamel, which is only 20 micrometers thick. The Brasilestes enamel is the thinnest of any Cretaceous mammal in the fossil record. Most Mesozoic mammals have enamel in the range of 100 to 300 micrometers”, Castro said.

“Tens of known species of xenarthrans are alive now. Hundreds are extinct. Only three have enamel. The microstructure of Brasilestes’ premolar enamel is very similar to that of the nine-banded armadillo“, said the FAPESP-supported researcher.

According to Castro, “molecular clock evidence suggests the xenarthran lineage started at least 85 million years ago. However, the oldest armadillo fossils, found in Rio de Janeiro, are about 50 million years old.”

While it is intriguing to imagine Brasilestes as an ancient xenarthran, it is far too soon for any such affirmation.

“The age and provenance of Brasilestes do match molecular hypotheses for the origin of the xenarthrans, but it would be premature to infer taxonomic affinity in light of the morphological differences between the Brasilestes tooth and armadillo teeth”, Castro said.

Langer agreed. “We have only one Brasilestes fossil. That’s nowhere near enough to extract conclusions from the fossil record”, he said.

The fact that no Mesozoic mammal fossils were found in Brazil before Brasilestes could mean such fossils are rare or too fragile to be preserved. “Who knows, one day we may find new Brasilestes fossils that help us understand its history better. It could take decades”, Langer said.

Small beetle that lived with dinosaurs discovered in amber


Kekveus jason. The amber sample with the new beetle trapped inside -- the beetle is the tiny speck indicated by the tip of a mechanical pencil for scale. Credit: Shuhei Yamamoto, Field Museum

From the Field Museum in the USA:

Tiny paragliding beetle that lived with dinosaurs discovered in amber, named ‘Jason’

June 7, 2018

Featherwing beetles are smaller than the period at the end of this sentence. They get their name from the feathery fringe on their wings that enables them to catch the air and float like dandelion seeds. And, it turns out, they go way back — scientists discovered a 99-million-year-old featherwing beetle preserved in amber, and they named it “Jason.”

“This tiny beetle lived during the Cretaceous Period, it saw actual dinosaurs“, says Shuhei Yamamoto, a researcher at the Field Museum in Chicago and co-lead author of a paper describing the beetle in Cretaceous Research. “The amber the beetle was found in is like a time capsule.”

The new beetle, the earliest member of its family to get a scientific name, is called Kekveus jason. “Jason” is a reference to the Greek hero who sailed the world in search of the Golden Fleece; “Kekveus”, meanwhile, doesn’t mean anything — co-lead author Vasily Grebennikov of the Canadian Food Inspection Agency, picked it because new genus names for little-known fossils often wind up changing when the species is later reclassified as scientists learn more about it. “From my perspective I always believe that an animal name should not have any meaning (except when named after a person), since if the authors are wrong, it might be odd to have later species ‘chinensis‘ endemic to Europe, or something similarly absurd”, says Grebennikov.

Yamamoto discovered the tiny sailing insect by poring over pieces of amber. Amber is made from fossilized resin, a sap-like substance produced by plants. When prehistoric insects got trapped in resin, their bodies would get incorporated into the amber that formed — think the mosquitos from Jurassic Park, minus the “resurrecting dinosaurs” part.

When Yamamoto spotted a tiny black speck in the amber, he was cautiously optimistic that he’d found a prehistoric insect. “I didn’t have much confidence at first, but after cutting and polishing the amber so I could get a better look, I realized, oh, this is truly an amazing fossil”, he says.

The beetle is only 0.536 millimeters long — it’s dwarfed by the tip of a mechanical pencil. But under a microscope, Yamamoto was able to glean details of its anatomy that revealed it as a different species and genus from living featherwing beetles. For instance, it has three grooves running like pinstripes up its body, a feature not found on its modern cousins. Overall, though, the researchers found that K. jason has a lot in common with featherwings alive today, meaning that the family of beetles evolved features like a tiny body size and fringed wings millions of years ago. According to Yamamoto, amber fossils yield a level of preservation rarely found in regular rock, especially for insects. “There are many rock fossils from the Jurassic and Cretaceous periods, but they’re limited to big animals like larger insects, mammals, dinosaurs, and birds, because small insects cannot be preserved in rock fossil very clearly. Only fossil insects in amber are preserved in fine detail, in three dimensions”, says Yamamoto. Yamamoto looks forward to further discoveries of prehistoric animals preserved in amber. “It’s likely that we’ll find more in the future — Burmese amber is one of the hottest fossils in the world,” he says. “There are so many great findings happening, literally day by day. Many important discoveries of insects will be made.”