Welsh Jurassic mammals feeding, new study


This video says about itself:

There Are No Transitional Fossils?

19 April 2011

Long-sought fossil mammal with transitional middle ear found in China.

Palaeontologists have announced the discovery of Liaoconodon hui, a complete fossil mammal from the Mesozoic found in China that includes the long-sought transitional middle ear.

The specimen was found by palaeontologists from the American Museum of Natural History and the Chinese Academy of Sciences.

It shows the bones associated with hearing in mammals, the malleus, incus, and ectotympanic, decoupled from the lower jaw, as had been predicted, but were held in place by an ossified cartilage that rested in a groove on the lower jaw.

People have been looking for this specimen for over 150 years since noticing a puzzling groove on the lower jaw of some early mammals,” Jin Meng, curator in the Division of Palaeontology at the Museum and first author of the paper, said.

“Now we have cartilage with ear bones attached, the first clear paleontological evidence showing relationships between the lower jaw and middle ear,” Meng revealed

The transition from reptiles to mammals has long been an open question, although studies of developing embryos have linked reptilian bones of the lower jaw joint to mammalian middle ear bones.

The new fossil, Liaoconodon hui, fills the gap in knowledge between the basal, early mammaliaforms like Morganucodon, where the middle ear bones are part of the mandible and the definitive middle ear of living and fossil mammals.

Liaoconodon hui is a medium-sized mammal for the Mesozioc (35.7 cm long from nose to tip of tail, or about 14 inches) and dates from 125 to 122 million years.

It is named in part for the bountiful fossil beds in Liaoning, China, where it was found.

The species name, hui, honours palaeontologist Yaoming Hu who graduated from the American Museum of Natural History-supported doctoral program and recently passed away.

The fossil is particularly complete, and its skull was prepared from both dorsal and ventral sides, allowing Meng and colleagues to see that the incus and malleus have detached from the lower jaw to form part of the middle ear.

These bones remain linked to the jaw by the ossified Meckels cartilage that rests in the groove on the lower jaw. The team hypothesizes that in this early mammal, the eardrum was stabilized with the ossified cartilage as a supporting structure.

“Before we did not know the detailed morphology of how the bones of the middle ear detached, or the purpose of the ossified cartilage,” Meng said.

“Liaoconodon hui changes previous interpretations because we now know the detailed morphology of the transitional mammal and can propose that the ossified cartilage is a stabilizer.

“I”ve always dreamed of a fossil with a good ear ossicle. Now, we have had this once in a lifetime discovery,” Meng added.

From the University of Southampton in England:

Jurassic mammals were picky eaters, new study finds

August 20, 2014

Summary:

New analyses of tiny fossil mammals from Glamorgan, South Wales are shedding light on the function and diets of our earliest ancestors, a team reports. Mammals and their immediate ancestors from the Jurassic period (201-145 million years ago) developed new characteristics – such as better hearing and teeth capable of precise chewing.

New analyses of tiny fossil mammals from Glamorgan, South Wales are shedding light on the function and diets of our earliest ancestors, a team including researchers from the University of Southampton report today in the journal Nature. Mammals and their immediate ancestors from the Jurassic period (201-145 million years ago) developed new characteristics — such as better hearing and teeth capable of precise chewing.

By analysing jaw mechanics and fossil teeth, the team were able to determine that two of the earliest shrew-sized mammals, Morganucodon and Kuehneotherium, were not generalised insectivores but had already evolved specialised diets, feeding on distinct types of insects.

Lead author, Dr Pamela Gill of the University of Bristol, said: “None of the fossils of the earliest mammals have the sort of exceptional preservation that includes stomach contents to infer diet, so instead we used a range of new techniques which we applied to our fossil finds of broken jaws and isolated teeth. Our results confirm that the diversification of mammalian species at the time was linked with differences in diet and ecology.”

The team used synchrotron X-rays and CT scanning to reveal in unprecedented detail the internal anatomy of these tiny jaws, which are only 2cm in length. As the jaws are in many pieces, the scans were ‘stitched together’ to make a complete digital reconstruction. Finite element modelling, the same technique used to design hip joints and bridges, was used to perform a computational analysis of the strength of the jaws. This showed that Kuehneotherium and Morganucodon had very different abilities for catching and chewing prey.

Study co-author, Dr Neil Gostling from the University of Southampton, said: “The improvement in CT scanning, both in the instrumentation, at Light Source at the Paul Scherrer Institute in Switzerland where we scanned or even the µ-VIS Centre at Southampton, along with access for research of this kind, allows us to make inroads into understanding the biology and the ecology of animals long dead. The questions asked of the technology do not produce ‘speculation’, rather the results show a clearly defined answer based on direct comparison to living mammals. This would not be possible without the computational techniques we have used here.”

Using an analysis previously carried out on the teeth of present-day, insect-eating bats, the researchers found that the teeth of Morganucodon and Kuehneotherium had very different patterns of microscopic pits and scratches, known as ‘microwear’. This indicated they were eating different things with Morganucodon favouring harder, crunchier food items such as beetles while Kuehneotherium selected softer foods such as scorpion flies which were common at the time.

Team leader, Professor Emily Rayfield from the University of Bristol, added: “This study is important as it shows for the first time that the features that make us unique as mammals, such as having only one set of replacement teeth and a specialised jaw joint and hearing apparatus, were associated with the very earliest mammals beginning to specialise their teeth and jaws to eat different things.”

Hallucigenia, strange Cambrian fossil animal, new study


This video from the USA is called Hallucigenia at the Chicago Field Museum.

From daily The Independent in Britain:

Hallucigenia revealed: The most surreal creature from strangest period in history of life on Earth

Scientists solve mystery of a creature from the Cambrian lagoons

Steve Connor, science editor

Saturday 16 August 2014

If Salvadore Dali were God, he would surely have designed an animal that looked like Hallucigenia. It has been described as the most surreal creature that lived in the strangest period in the history of life on Earth, more than 500 million years ago.

After more than four decades of studying fossilised imprints, scientists believe they have finally nailed Hallucigenia’s position in the tree of life, and in the process discovered its only living descendants.

Hallucigenia, named because of its dream-like, trip-inducing appearance, is one of the many marine animals that rather abruptly appear in the fossil record during a period in pre-history known as the Cambrian explosion, a biological bang that detonated the evolution of complex life-forms about 542 million years ago.

Until the Cambrian explosion, life had been bumbling along for about three billion years, with evolution producing nothing much more animate than a bath sponge. After the explosion, creatures with complex body plans evolved that walked, crawled, swam and burrowed – and Hallucigenia was one of them.

Scientists were so thrown by Hallucigenia when its small fossils were first analysed 40 years ago that they thought its front end was its back end, and its top was its bottom. They even thought it was an evolutionary one-off that had left no descendants alive today.

However, scientists now believe they have finally been able to locate Hallucigenia’s position in evolutionary history by showing that it is the ancestor of a small group of worm-like creatures with short, stubby legs that can be found today, living unobtrusively in the undergrowth of tropical forests.

Martin Smith and Javier Ortega-Hernandez of Cambridge University have detected key physical similarities between Hallucigenia and the so-called velvet worms, known more formally as the onychophorans – the first time zoologists have been able to rule conclusively on the creature’s true role in history.

Their study, to be published in the journal Nature, is based on a detailed analysis of high-magnification images of the fossils of Hallucigenia, which grew no bigger than about 3.5cm long, showing five key characteristics that link the species to the velvet worms.

Among the most important features is the way the claws at the end of its limbs are arranged. Under an electron microscope, each claw has two or three successive layers of cuticle nestled one within the other, like the layered skins of an onion.

Dr Smith said: “We think this enabled them to grow a new set of claws before they shed their skins, which they had to do to grow. A very similar feature is found in the claws and jaws of the velvet worms, and no other animal shares this particular characteristic.

“It means that the animals do not have to wait for a new claw to form after shedding their skin to grow – they already have one ready formed,” he explained.

Zoologists have also not always been completely sure which end of Hallucigenia is the front and which is the back, although Dr Smith said his research clears this up – the front has two or three pairs of appendages and the back has a rounded end where its body-length gut probably terminates.

It is now clear that the fearsome spikes on Hallucigenia’s back, which were once confused for stilt-like legs, are almost certainly a defensive mechanism against the increasing number of predators that emerged during the Cambrian explosion.

Fossils: Burgess Shale

The Cambrian explosion is named after the geological period that began about 541 million years ago, when a remarkable variety of marine animals first appear in the fossil record.

Most fossils are formed from the hard parts of living organism, such as bones or shells. However, details of the soft body parts of Cambrian creatures can be seen in a rock formation known as the Burgess Shale in the Canadian Rocky Mountains.

Hallucigenia was just one of many bizarre animals to live at this time. Other creatures included a fearsome predator called Anomalocaris, armed with two vicious-looking jaws and large eyes, and Wiwaxia, which looked like a Viking helmet with spikes.

For evolutionists, this period is one of the most interesting in the 3.5-billion-year history of life on earth because this was when many of the complex body plans seen in today’s animals are first detectable, even though they must have evolved from something earlier in history.

“It’s often thought that modern animal groups arose fully formed during the Cambrian explosion. But evolution is a gradual process,” said Martin Smith of Cambridge.

“Today’s complex anatomies emerged step by step, one feature at a time. By deciphering ‘in-between’ fossils like Hallucigenia, we can determine how different animal groups built up their modern body plans,” he said.

Burgess Shale Fossil Specimens: here.

‘Butterfly-headed’ pterosaurs discovery in Brazil


A new species of flying reptile from the Cretaceous Era, Caiuajara dobruskiii, has been unearthed in southern Brazil. The creature, described in a 2014 PLOS ONE paper, sported a bony crest on its head. Credit: Maurilio Oliveira/Museu Nacional-UFRJ

From Live Science:

Flock of Ancient ‘Butterfly-Headed’ Flying Reptiles Discovered

By Tia Ghose, Staff Writer

August 13, 2014 02:00pm ET

An ancient flying reptile with a bizarre, butterflylike head has been unearthed in Brazil.

The newfound reptile species, Caiuajara dobruskii, lived about 80 million years ago in an ancient desert oasis. The beast sported a strange bony crest on its head that looked like the wings of a butterfly, and had the wingspan needed to take flight at a very young age.

Hundreds of fossils from the reptile were unearthed in a single bone bed, providing the strongest evidence yet that the flying reptiles were social animals, said study co-author Alexander Kellner, a paleontologist at the Museu Nacional/Universidade Federal do Rio de Janeiro in Brazil. [See Images of the Bizarre 'Butterfly Head' Reptile]

Rare find

Though pterosaur fossils have been unearthed in northern Brazil, no one knew of pterosaurs fossils in the southern part of the country. In the 1970s, a farmer named Dobruski and his son discovered a massive Cretaceous Period bone bed in Cruzeiro do Oeste in southern Brazil, a region not known for any fossils, Kellner said. The find was forgotten for decades, and then rediscovered just two years ago. The team dubbed the reptile Caiuajara dobruskii, after the geologic formation, called the Caiuá Group, where it was found, as well as the farmer who discovered the species, Kellner said.

C. dobruskii belonged to a group of winged reptiles known as pterosaurs, which are more commonly known as pterodactyls.

Hundreds of bone fragments from the species were crammed in an area of just 215 square feet (20 square meters). At least 47 individuals — and possibly hundreds more — were buried at the site. All but a few were juveniles, though the researchers found everything from youngsters with wingspans of just 2.1 feet (0.65 m) long to adults with wingspans reaching 7.71 feet (2.35 m). The fossils weren’t crushed, so the 3D structure of the animals was preserved, the authors wrote in a research article published today (Aug. 13) in the journal PLOS ONE.

The ancient reptiles’ bony crests changed in size and orientation as the pterosaurs grew.

Because the adult skeletal size (other than the head) wasn’t much different from the juveniles’, the researchers hypothesized that C. dobruskii was fairly precocious and could fly at a young age, Kellner said.

Water congregation

Based on the sediments in which the bones were found, the area was once a vast desert with a central oasis nestled between the sand dunes, the authors wrote in the paper.

Ancient C. dobruskii colonies may have lived around the lake for long periods of time and died during periods of drought or during storms. As the creatures died, the occasional desert storm would wash their remains into the lake, where the watery burial preserved them indefinitely, the researchers said. Another possibility is that the pterosaurs stopped at this spot during ancient migrations, though the authors suspect that is less likely.

The bone bed, with its hundreds of individuals in well-dated geological layers, is some of the strongest evidence yet that the fruit-eating animals were social, Kellner said.

“This was a flock of pterosaurs,” Kellner told Live Science.

This finding, in turn, strengthens evidence that other pterosaur species may have been social as well, the authors wrote in the paper.

New dinosaur discovery in Venezuela


This video is called New type of dinosaur Laquintasaura venezuelae was turkey-sized.

From Wildlife Extra:

A new species of dinosaur that roamed northern South America 200 million years ago has been discovered in Venezuela.

This is the first time a dinosaur has been has been found here and in this honour it has been named Laquintasaura venezuelae.

Measuring about a metre long and 25 centimetres tall Laquintasaura would have been about the size of a small dog and belong to the ‘bird-hipped’, or Ornithischia, group of dinosaurs which later gave rise to Stegosaurus.

It was largely herbivorous- though the curve of some of its teeth suggest it might have also feasted on insects and small prey.

The discovery of it in small groups, which included juveniles and fully grown adults, could indicate they were living in herds; something that was not thought to have occurred in this sort of dinosaur until the Late Jurassic around 40 million years later.

‘It is fascinating and unexpected to see they lived in herds, something we have little evidence of so far in dinosaurs from this time,’ says lead author Dr Paul Barrett. “It’s always exciting to discover a new dinosaur species but there are many surprising firsts with Laquintasaura.”

See also here.

The scientific description of this new species is here.

Dinosaurs got extinct, how about dinosaur age plants?


This video says about itself:

The Day The Mesozoic Died HD

30 May 2013

The disappearance of the dinosaurs at the end of the Cretaceous period posed one of the greatest, long-standing scientific mysteries. This three-act film tells the story of the extraordinary detective work that solved it. Shot on location in Italy, Spain, Texas, Colorado, and North Dakota, the film traces the uncovering of key clues that led to the stunning discovery that an asteroid struck the Earth 66 million years ago, triggering a mass extinction of animals, plants, and even microorganisms. Each act illustrates the nature and power of the scientific method. Representing a rare instance in which many different disciplines—geology, physics, biology, chemistry, paleontology—contributed to a revolutionary theory, the film is intended for students in all science classes.

From Laelaps blog today:

Planting the Cenozoic Garden

by Brian Switek

Sixty six million years ago, a global catastrophe extinguished the non-avian dinosaurs. This is common knowledge. It’s also too narrow a view. Various forms of life disappeared in the same geologic instant – from coil-shelled ammonites to some forms of mammal – and others, for reasons as yet unknown, survived.

Plants are among the neglected of the victims and survivors. A magnolia tree does not hold the same cultural cachet as Tyrannosaurus. The post-impact “fern spike” is often cited as a symbol of wide-ranging devastation, but, outside technical journals, that’s about the extent of our attention span for paleoflora. That’s a shame. If we’re going to understand how life on Earth was so deeply wounded 66 million years ago, and how it bounced back, we should be looking more closely at the prehistoric garden.

Hot on the heels of a review summarizing the global dinosaurian picture at the end of the Cretaceous, Lund University paleobotanists Vivi Vajda and Antoine Bercovici have now assembled a view of how plants were affected by the Earth’s fifth mass extinction. Prehistoric pollen and spores tell the story.

The advantage of looking at fossil pollen, Vajda and Bercovici write, is that there’s plenty of it. That’s not only because plants produce large amounts of the reproductive material, but because pollen is also incredibly durable. If you want to see who’s living where, and how environments change through time, these microscopic plant fossils are good way to do it.

In some ways, the story of the Cretaceous plants echoes what paleontologists have found among other forms of life. The Cretaceous world was a highly-dynamic one marked by fluctuating sea levels, the further breakup of continents, and the formation of new mountain ranges. All this moving and shuffling created evolutionary pockets where new species could evolve in relative isolation, becoming restricted to their particular province. Plants proliferated and evolved according to these boundaries just as dinosaurs did.

Each of the pollen provinces, outlined by Vajda and Bercovici, have their own distinctive profile. In northern North America, Asia, and a few spots in South America, Late Cretaceous sediments commonly contain Aquilapollenites – pollen thought to have come from a group of plants closely related to the modern sandalwood. A neighboring province – stretching from eastern North America to the Himalayas – is dominated by pollen from a Cretaceous birch relative, while rocks from the same time in northern South America, central Africa, and India are rife with pollen from palms. Rounding out the set, a southern hemisphere swath has plenty of pollen from plants related to southern beeches and shrubs.

These were not the only plants to exist in those areas, of course, but their pollen broadly delineates differentiated patches. Paleobotanists can zoom in from there, and, as with dinosaurs, the best-studied sites on the planet document the end of the Cretaceous through the beginning of the Paleogene in western North America.

The forests that Tyrannosaurus and Triceratops knew were dominated by angiosperms – flowering plants – with some conifers, ferns, ginkgos, and cycads for good measure. Palm trees stood alongside evergreens and towered above a shrubby understory in these Late Cretaceous forests. In the aftermath of the impact 66 million years ago, however, those forests were replaced by a relatively small collection of angiosperms, a shadow of the diversity that the Edmontosaurus and kin knew.

Plants suffered extinctions just as many other forms of life did. In fact, some of them dwindle to nothing right at the K-Pg boundary are called “K-species” or “K-taxa.” In the pollen record of North America, for example, the sandalwood relative and a suite of species in seven other genera give way to species in just two genera. Overall, about 60% of plant species present in Cretaceous North America went extinct. The rest of the globe reflects a similar pattern, albeit with different species. Many pollen-producing plants either went entirely extinct or became much less abundant.

Clues from the earliest days of the Paleogene track how plant life eventually bounced back. While sites in New Zealand preserve a “fungal spike” from when mushrooms and their ilk thrived on decomposing matter under blacked-out skies, the subsequent “fern spike” records when pioneering plants – primarily ferns – quickly spread as sunlight began to return. The angiosperms, as well as some conifers, followed, but with fewer species than before. Depending on the location, plant life took between one and ten million years to recover to pre-extinction levels of diversity.

As with the animals, though, why some plants went extinct and others persisted is a mystery. Perhaps some were simply lucky enough to grow in places that were less affected by the devastation following the asteroid strike. Then again, Vajda and Bercovici point out, some researchers have suggested that plants carrying additional sets of chromosomes – or were polyploid – might have had the genetic flexibility to more quickly adapt after ecological shock.

Discerning what made a survivor isn’t just an exercise in replaying ancient history, though.

Vajda and Bercovici argue that two previous mass extinctions – roughly 251 and 200 million years ago – follow a similar pattern of a highly-diverse flora being pruned back, followed by crisis species, pioneer communities, and ecosystem recovery in sequence. Which left me to wonder if we’re going to see this pattern again. If  we’re not yet in a Sixth Extinction, we’re close, and identifying likely survivors verses vulnerable species is an essential part of conservation triage. By sifting through the past, down to the tiniest pollen grain, we can reflect on what sort of future we want to create.

Reference:

Vajda, V., Bercovici, A. 2014. The global vegetation pattern across the Cretaceous-Paleogene mass extinction interval: A template for other extinction events. Global and Planetary Change. doi: 10.1016/j.gloplacha.2014.07.014

Whale fossil discovery in California


This video is called Rare Whale Fossil Pulled From Calif. Backyard.

From Associated Press:

Rare whale fossil pulled from Calif. yard

By MATT HAMILTON

Saturday, August 2, 2014 1:06 AM EDT

RANCHO PALOS VERDES, Calif. — A search-and-rescue team pulled a rare half-ton whale fossil from a Southern California backyard Friday, a feat that the team agreed to take on as a makeshift training mission.

The 16- to 17-million-year-old fossil from a baleen whale is one of about 20 baleen fossils known to exist, Natural History Museum of Los Angeles County paleontologist Howell Thomas said. Baleen is a filter made of soft tissue that is used to sift out prey, like krill, from seawater.

The fossil, lodged in a 1,000-pound boulder, was hoisted from a ravine by Los Angeles County Sheriff’s Department search-and-rescue volunteers. Using pulleys and a steel trolley, crews pulled the fossil up a steep backyard slope and into a truck bound for the museum.

Gary Johnson, 53, first discovered the fossil when he was a teen exploring the creek behind his family’s home.

At the time, he called another local museum to come inspect the find, but officials passed on adding it to their collection. In January, a 12-million-year-old sperm whale fossil was recovered at a nearby school, prompting Johnson to call the Natural History Museum.

“I thought, maybe my whale is somehow associated,” said Johnson, who works as a cartoonist and art director.

Thomas wanted to add the fossil to the county museum’s collection of baleen whale fossils, but was puzzled over how to get the half-ton boulder from Rancho Palos Verdes, located on a peninsula about 25 miles southwest of downtown Los Angeles.

The sheriff’s department search-and-rescue unit declined to send a helicopter, but offered to use the fossil recovery as a training mission. The volunteer crew typically rescues stranded hikers and motorcyclists who careen off the freeway onto steep, rugged terrain, search-and-rescue reserve chief Mike Leum said.

“We’ll always be able to say, ‘it’s not heavier than a fossil,”‘ Leum said.

Bush-crickets’ ultrasonic hearing abilities, new research


This video is called Stridulating Green Bush-Crickets (Tettigonia viridissima) – 2013-08-04.

From the University of Lincoln in England:

Scientists to explore how insects evolved ultrasonic hearing abilities over millennia

06 August 2014 University of Lincoln

A grant of £250,000 from The Leverhulme Trust has been awarded to a team of scientists led by the University of Lincoln, UK, to study how a group of insects evolved incredible ultrasonic hearing abilities.

A cochlear organ for frequency selectivity was thought to be unique to hearing in mammals until a similar mechanism for frequency analysis was found in the ears of bushcrickets in South American rainforests two years ago.

Scientists believe the discovery of this previously unidentified hearing organ could pave the way for technological advancements in bio-inspired acoustic sensors, including medical imaging devices and hearing aids.

The new research project, funded by The Leverhulme Trust, aims to develop an integrated understanding of the evolution of ultrasonic hearing in bushcrickets; specifically how they developed cochlear-like systems in response to changing evolutionary pressures over millions of years.

Project lead Dr Fernando Montealegre-Z, from the School of Life Sciences, University of Lincoln, UK, led the team who discovered the previously unidentified hearing organ in bushcrickets.

He explained: “We will study these hearing systems and their variation in many species of bushcrickets. There are around 7,000 living species of these insects, but what we know about cochlear mechanisms has been investigated in only two or three. Therefore we expect to find enormous amount of variation across species. Through data from fossils and existing species, we aim to unveil major changes in sensory ecological niches and in the auditory ecology of species which have evolved from a single ancestral species.”

Bushcrickets are among the first terrestrial animals to have evolved acoustic communication. The sound emitted by crickets is produced by the stridulatory organ, a large vein running along the bottom of one wing, covered with “teeth”, which is rubbed against a plectrum on the other wing. The ears, located on their forelegs, are used in mating and predator avoidance.

Nearly 70 per cent of the living species, measured with ultrasound-sensitive equipment, produce acoustic signals in the ultrasonic range. However, their ancestors communicated at much lower frequencies. Modern bushcrickets emerged some 55-60 million years ago. Since bats arose at about the same time, the group hypothesise that bushcrickets might have evolved ultrasonic communication and elaborate hearing organs in response to acoustic predators, such as echolocating bats.

For the first time, the group will reconstruct changes in shape and function of fossil bushcrickets’ auditory and stridulatory organs throughout the recorded history of this group, from the Triassic onwards. This will enable them to understand the selective pressures that drove the evolution of cochlear systems in mammals and insects.

The work will enable the construction of a series of biophysical models that will simulate and predict tympanal vibrations and wing resonances in extinct bushcrickets, plus the acoustic reconstruction of the bushcricket community that lived in the long-gone forests of the Triassic and Jurassic eras.

Dr Montealegre-Z said: “Findings will help to comprehend the multiple origins and diversity of auditory mechanisms in mammals and insects. Results will also open up our understanding of the acoustic ecology of extinct environments where other auditory animals lived, and not only provide insights into the lives of singing insects, but that of their prey and predators. Studying fossil insects advances our general understanding of both behavioural and physical ecologies of the forests of the distant past.

“The research encompasses several disciplines including paleontology, biophysics, physiology and engineering. The integration of these disciplines is original and innovative and will open up new opportunities to enhance the current knowledge of sensory mechanisms in living organisms, including humans.”