Dinosaur discovery in Chile, missing link?


This video says about itself:

4 September 2015

“Chilesaurus” is an extinct genus of herbivorous theropod dinosaur. The genus is monotypic, represented by the type species “Chilesaurus diegosuarezi“. “Chilesaurus” lived approximately 145 million years ago in the Late Jurassic period of Chile.

Fossils of “Chilesaurus”, a vertebra and a rib, were first discovered on 4 February 2004 by the seven-year-old Diego Suárez who, together with his parents, geologists Manuel Suárez and Rita de la Cruz, was searching for decorative stones in the Aysén Region. More specimens were present that in 2008 were reported as representing several dinosaurian species. Only later was it realised that these belonged to a single species with a bizarre combination of traits.

In 2015, the type species “Chilesaurus diegosuarezi” was named and described by Fernando Emilio Novas, Leonardo Salgado, Manuel Suárez, Federico Lisandro Agnolín, Martín Dário Ezcurra, Nicolás Chimento, Rita de la Cruz, Marcelo Pablo Isasi, Alexander Omar Vargas and David Rubilar-Rogers. The generic name refers to Chile. The specific name honours Diego Suárez.

The holotype, “SNGM-1935”, was found in a layer of the Toqui Formation dating from the late Tithonian. It consists of an articulated rather complete skeleton with skull of a juvenile individual, lacking the feet and most of the tail. Four other partial skeletons and several single bones are the paratypes. They represent juvenile and adult individuals.

“Chilesaurus” measures 3.2 m from nose to tail. The holotype is a smaller individual of half that length.

That was in 2015. But now …

From Biology Letters:

A dinosaur missing-link? Chilesaurus and the early evolution of ornithischian dinosaurs

Matthew G. Baron, Paul M. Barrett

16 August 2017

Abstract

The enigmatic dinosaur taxon Chilesaurus diegosuarezi was originally described as a tetanuran theropod, but this species possesses a highly unusual combination of features that could provide evidence of alternative phylogenetic positions within the clade.

In order to test the relationships of Chilesaurus, we added it to a new dataset of early dinosaurs and other dinosauromorphs. Our analyses recover Chilesaurus in a novel position, as the earliest diverging member of Ornithischia, rather than a tetanuran theropod. The basal position of Chilesaurus within the clade and its suite of anatomical characters suggest that it might represent a ‘transitional’ taxon, bridging the morphological gap between Theropoda and Ornithischia, thereby offering potential insights into the earliest stages of ornithischian evolution, which were previously obscure. For example, our results suggest that pubic retroversion occurred prior to some of the craniodental and postcranial modifications that previously diagnosed the clade (e.g. the presence of a predentary bone and ossified tendons).

1. Introduction

Chilesaurus diegosuarezi is from the Late Jurassic (Tithonian; ca 150 Ma) Toqui Formation of Chile and possesses a bizarre suite of anatomical features that, if considered individually, are usually thought to characterize distantly related dinosaur clades.

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Jurassic ‘flying’ mammals discovery


This video says about itself:

Flying Squirrel | World’s Weirdest

9 January 2013

Flying isn’t just for the birds. A stretchy membrane and rudder-like tail help this little mammal sail through the treetops, avoiding land-bound predators with ease.

From the University of Chicago Medical Center in the USA:

First winged mammals from the Jurassic period discovered

160-million-year-old fossils suggest a new model of life — gliding — for the forerunners of mammals, in an evolutionary parallel to modern mammal gliders

August 9, 2017

Two 160 million-year-old mammal fossils discovered in China show that the forerunners of mammals in the Jurassic Period evolved to glide and live in trees. With long limbs, long hand and foot fingers, and wing-like membranes for tree-to-tree gliding, Maiopatagium furculiferum and Vilevolodon diplomylos are the oldest known gliders in the long history of early mammals.

The new discoveries suggest that the volant, or flying, way of life evolved among mammalian ancestors 100 million years earlier than the first modern mammal fliers. The fossils are described in two papers published this week in Nature by an international team of scientists from the University of Chicago and Beijing Museum of Natural History.

“These Jurassic mammals are truly ‘the first in glide,'” said Zhe-Xi Luo, PhD, professor of organismal biology and anatomy at the University of Chicago and an author on both papers. “In a way, they got the first wings among all mammals.”

“With every new mammal fossil from the Age of Dinosaurs, we continue to be surprised by how diverse mammalian forerunners were in both feeding and locomotor adaptations. The groundwork for mammals’ successful diversification today appears to have been laid long ago,” he said.

Adaptations in anatomy, lifestyle and diet

The ability to glide in the air is one of the many remarkable adaptations in mammals. Most mammals live on land, but volant mammals, including flying squirrels and bats that flap bird-like wings, made an important transition between land and aerial habitats. The ability to glide between trees allowed the ancient animals to find food that was inaccessible to other land animals. That evolutionary advantage can still be seen among today’s mammals such as flying squirrels in North America and Asia, scaly-tailed gliders of Africa, marsupial sugar gliders of Australia and colugos of Southeast Asia.

Maiopatagium reconstruction, © April I. Neander, University of Chicago

The Jurassic Maiopatagium and Vilevolodon are stem mammaliaforms, long-extinct relatives of living mammals. They are haramiyidans, an entirely extinct branch on the mammalian evolutionary tree, but are considered to be among forerunners to modern mammals. Both fossils show the exquisitely fossilized, wing-like skin membranes between their front and back limbs. They also show many skeletal features in their shoulder joints and forelimbs that gave the ancient animals the agility to be capable gliders. Evolutionarily, the two fossils, discovered in the Tiaojishan Formation northeast of Beijing, China, represent the earliest examples of gliding behavior among extinct mammal ancestors.

The two newly discovered creatures also share similar ecology with modern gliders, with some significant differences. Today, the hallmark of most mammal gliders is their herbivorous diet that typically consists of seeds, fruits and other soft parts of flowering plants.

But Maiopatagium and Vilevolodon lived in a Jurassic world where the plant life was dominated by ferns and gymnosperm plants like cycads, gingkoes and conifers — long before flowering plants came to dominate in the Cretaceous Period, and their way of life was also associated with feeding on these entirely different plants. This distinct diet and lifestyle evolved again some 100 million years later among modern mammals, in examples of convergent evolution and ecology.

“It’s amazing that the aerial adaptions occurred so early in the history of mammals,” said study co-author David Grossnickle, a graduate student at the University of Chicago. “Not only did these fossils show exquisite fossilization of gliding membranes, their limb, hand and foot proportion also suggests a new gliding locomotion and behavior.”

Thriving among dinosaurs

Early mammals were once thought to have differences in anatomy from each other, with limited opportunities to inhabit different environments. The new glider fossils from the dinosaur-dominated Jurassic Period, along with numerous other fossils described by Luo and colleagues in the last 10 years, however, provide strong evidence that ancestral mammals adapted to their wide-ranging environments despite competition from dinosaurs.

“Mammals are more diverse in lifestyles than other modern land vertebrates, but we wanted to find out whether early forerunners to mammals had diversified in the same way,” Luo said. “These new fossil gliders are the first winged mammals, and they demonstrate that early mammals did indeed have a wide range of ecological diversity, which means dinosaurs likely did not dominate the Mesozoic landscape as much as previously thought.”

Dinosaur age plants, new research


This BBC video is called David Attenborough‘s Kingdom of Plants.

From Lund University in Sweden:

Through fossil leaves, a step towards Jurassic Park

July 4, 2017

Summary: The relationships between 200-million-year-old plants have been established for the first time, based on chemical fingerprints. Using infrared spectroscopy and statistical analysis of organic molecules in fossil leaves, they are opening up new perspectives on the dinosaur era.

For the first time, researchers have succeeded in establishing the relationships between 200-million-year-old plants based on chemical fingerprints. Using infrared spectroscopy and statistical analysis of organic molecules in fossil leaves, they are opening up new perspectives on the dinosaur era.

The unique results stem from a collaboration between researchers at Lund University, the Swedish Museum of Natural History in Stockholm, and Vilnius University.

“We have solved many questions regarding these extinct plants’ relationships. These are questions that science has long been seeking answers to,” says Vivi Vajda, a professor at the Department of Geology at Lund University and active at the Swedish Museum of Natural History.

The researchers have collected fossil leaves from rocks in Sweden, Australia, New Zealand and Greenland. Using molecular spectroscopy and chemical analysis, the fossil leaves were then compared with the chemical signatures from molecules in plant leaves picked at the Botanical Garden in Lund.

The use of genetic DNA analysis in modern research to determine relationships is not possible on fossil plants. The oldest DNA fragments ever found are scarcely one million-years-old. Therefore, the scientists searched for organic molecules to see what these could reveal about the plants’ evolution and relationships.

The molecules were found in the waxy membrane, which covers the leaves and these showed to differ between various species. The membrane has been preserved in the fossil leaves, some of which are 200 million-years-old.

Using infrared spectroscopy, the researchers carried out analyses in several stages. Firstly, they examined leaves from living plants that have relatives preserved in the fossil archive. The analysis showed that the biomolecular signatures were similar among plant groups, much in the same way as shown by modern genetic DNA analysis.

When the method was shown to work on modern plants, the researchers went on to analyse their extinct fossil relatives. Among others, they examined fossil leaves from conifers and several species of Ginkgo. The only living species of Ginkgo alive today is Ginkgo biloba, but this genus was far more diverse during the Jurassic.

“The results from the fossil leaves far exceeded our expectations, not only were they full of organic molecules, they also grouped according to well-established botanical relationships, based on DNA analysis of living plants i.e. Ginkgoes in one group, conifers in another,” says Vivi Vajda.

Finally, when the researchers had shown that the method gave consistent results, they analysed fossils of enigmatic extinct plants that have no living relatives to compare them with. Among others, they examined Bennettites and Nilssonia, plants that were common in the area that is now Sweden during the Triassic and Jurassic around 250-150 million years ago. The analysis showed that Bennettites and Nilssonia are closely related. On the other hand, they are not closely related to cycads, which many researchers had thought until now.

Per Uvdal, Professor of Chemical Physics at Lund University and one of the researchers who conducted the study, considers that the overall results are astounding.

“The great thing about the biomolecules in the leaves’ waxy membranes is that they are so much more stable than DNA. As they reflect, in an indirect way, a plant’s DNA can preserve information about the DNA. Therefore, the biomolecules can tell us how one plant is related in evolutionary terms to other plants,” he says.

The researchers are now going to extend their studies to more plant groups.

Gigantic Jurassic crocodile discovered in Madagascar


This video from Italy says about itself:

Reconstructing the skull of Razanandrongobe sakalavae

4 July 2017

Computed tomography of the fossil cranial bones of Razanandrongobe sakalavae (this is the name of this Jurassic crocodylomorph) provided information on the tooth replacement process and tooth/root size. The largest dentary tooth is 14 cm long and the largest premaxillary tooth measures 15 cm. CT data also allowed to 3-D print the missing counterlateral bones at FabLab Milan, and so to reconstruct the front of the skull at the Natural History Museum of Milan. Technician Andrea Passoni mounts the bone pieces.

Video: Cristiano Dal Sasso.

From ScienceDaily:

Gigantic crocodile with T. rex teeth was a top land predator of the Jurassic in Madagascar

Paleontologists document the features of a giant crocodile relative — the largest and oldest known ‘notosuchian‘, predating the other forms by 42 million years

July 4, 2017

Summary: Little is known about the origin and early evolution of the Notosuchia, hitherto unknown in the Jurassic period. New research on fossils from Madagascar begin to fill the gap in a million-year-long ghost lineage. Deep and massive jaw bones armed with enormous serrated teeth that are similar in size and shape to those of a T. rex strongly suggest that these animals fed also on hard tissue such as bone and tendon.

Little is known about the origin and early evolution of the Notosuchia, hitherto unknown in the Jurassic period. New research on fossils from Madagascar, published in the peer-reviewed journal PeerJ by Italian and French paleontologists, begin to fill the gap in a million-year-long ghost lineage.

Deep and massive jaw bones armed with enormous serrated teeth that are similar in size and shape to those of a T-rex strongly suggest that these animals fed also on hard tissue such as bone and tendon. The full name of the predatory crocodyliform (nicknamed ‘Razana’) is Razanandrongobe sakalavae, which means “giant lizard ancestor from Sakalava region.”

A combination of anatomical features clearly identify this taxon as a Jurassic notosuchian, close to the South American baurusuchids and sebecids, that were highly specialized predators of terrestrial habits, different from present-day crocodilians in having a deep skull and powerful erect limbs. “Like these and other gigantic crocs from the Cretaceous, ‘Razana’ could outcompete even theropod dinosaurs, at the top of the food chain,” says Cristiano Dal Sasso, of the Natural History Museum of Milan.

Razanandrongobe sakalavae is by far the oldest — and possibly the largest — representative of the Notosuchia, documenting one of the earliest events of exacerbated increase in body size along the evolutionary history of the group.

“Its geographic position during the period when Madagascar was separating from other landmasses is strongly suggestive of an endemic lineage. At the same time, it represents a further signal that the Notosuchia originated in southern Gondwana,” remarks co-author Simone Maganuco.

Old dinosaur, new research


This video is called Megalosaurus Tribute – You’re Going Down.

From the University of Warwick in England:

World’s ‘first named dinosaur’ reveals new teeth with scanning tech

June 7, 2017

Summary: Pioneering technology has shed fresh light on the world’s first scientifically-described dinosaur fossil — over 200 years after it was first discovered — thanks to research.

Pioneering technology has shed fresh light on the world’s first scientifically-described dinosaur fossil — over 200 years after it was first discovered — thanks to research by WMG at the University of Warwick and the University of Oxford’s Museum of Natural History.

Professor Mark Williams at WMG has revealed five previously unseen teeth in the jawbone of the Megalosaurus — and that historical repairs on the fossil may have been less extensive than previously thought.

Using state of the art CT scanning technology and specialist 3D analysis software, Professor Williams took more than 3000 X-ray images of the world-famous Megalosaurus jawbone, creating a digital three-dimensional image of the fossil.

In an unprecedented level of analysis, Professor Williams at WMG was able to see inside the jawbone for the first time, tracing the roots of teeth and the extent of different repairs.

Some damage occurred to the specimen when it was removed from the rock, possibly shortly after it was discovered.

Records at the Oxford University Museum of Natural History suggest that some restoration work may have been undertaken by a museum assistant between 1927 and 1931, while repairing the specimen for display — but there are no details about the extent of the repairs or the materials used.

The scans have revealed previously unseen teeth that were growing deep within the jaw before the animal died — including the remains of old, worn teeth and also tiny newly growing teeth.

The scans also show the true extent of repairs on the fossil for the first time, revealing that there may have been at least two phases of repair, using different types of plaster. This new information will help the museum make important decisions about any future restoration work on the specimen.

This research was made possible through a collaboration between Professor Williams’ research group at WMG, University of Warwick — including PhD researcher Paul Wilson — and Professor Paul Smith, director of the Oxford University Museum of Natural History.

Professor Williams commented: “Being able to use state-of-the-art technology normally reserved for aerospace and automotive engineering to scan such a rare and iconic natural history specimen was a fantastic opportunity.

“When I was growing up I was fascinated with dinosaurs and clearly remember seeing pictures of the Megalosaurus jaw in books that I read. Having access to and scanning the real thing was an incredible experience.”

The Megalosaurus jawbone is on display at the Oxford University Museum of Natural History alongside other bones from the skeleton.

Megalosaurus — which means ‘Great Lizard’ — was a meat-eating dinosaur which lived in the Middle Jurassic, around 167 million years ago. It would have been about 9 metres long and weighed about 1.4 tonnes (1400 kg).

The research was recently presented at the Institute of Electrical and Electronics Engineers (IEEE)’s International Instrumentation and Measurement Technology Conference in Torino, Italy.

See also here.

Jurassic dinosaurs, new study


This 1 July 2016 video from Utah in the USA is called Unlocking the mystery of the Cleveland-Lloyd Dinosaur Quarry.

From PeerJ:

New data for old bones: How the famous Cleveland-Lloyd dinosaur bone bed came to be

Scientists have debated for decades the origin of the densest collection of Jurassic dinosaur bones; X-ray and chemical analyses by paleontologists begin to unravel the mystery

June 6, 2017

Summary: The Cleveland-Lloyd Dinosaur Quarry is the densest collection of Jurassic dinosaur fossils. Since its discovery in the 1920s, numerous hypotheses have been proposed to explain the origin of the quarry. Were the dinosaurs poisoned? Did they die due to drought? Were they trapped in quick sand? A new study suggests that the quarry represents numerous mortality events which brought the dinosaurs to the site over time, rather than a single fatal event.

The Cleveland-Lloyd Dinosaur Quarry is the densest collection of Jurassic dinosaur fossils. Unlike typical Jurassic bone beds, it is dominated by the famous predatory dinosaur Allosaurus.

Since its discovery in the 1920s, numerous hypotheses have been proposed to explain the origin of the quarry. Were the dinosaurs poisoned? Did they die due to drought? Were they trapped in thick mud?

A new study published in the peer-reviewed journal PeerJ introduces modern techniques to better understand the landmark site’s history, suggesting that the quarry represents numerous mortality events which brought the dinosaurs to the site over time, rather than a single fatal event.

This study reveals that the small bone fragments were created during drought periods by weathering and erosion of bones disintegrating at the surface. During flood periods, however, the carcasses of Allosaurus and other dinosaurs washed in and rotted in a small pond, creating an environment in which fish, turtles, and crocodiles could not survive, and other dinosaurs would not eat the carcasses.

The data generated from new and innovative methods, including chemical analyses and the study of microscopic bone fragments, suggest that dinosaur bones were introduced to the deposit after death. This would also explain the unusual lack of typical pond fossils at the site, as well as the near lack of gnaw marks on bones and calcite and barite concretions found on bones excavated from the quarry.

The new hypothesis helps paleontologists understand the setting of the quarry, and to begin to unravel the mystery that led to this unique, Allosaurus-dominated bone bed.

Feathered dinosaurs, new research


This video says about itself:

29 July 2015

“Anchiornis” is a genus of small, feathered, eumaniraptoran dinosaurs. The genus “Anchiornis” contains only the type species “Anchiornis huxleyi“. It was named in honor of Thomas Henry Huxley, an early proponent of biological evolution, and the first to propose a close evolutionary relationship between birds and dinosaurs. The generic name “Anchiornis” means “near bird”, and its describers cited it as important in filling a gap in the transition between the body plans of birds and dinosaurs.

“Anchiornis huxleyi” fossils have been found in the Tiaojishan Formation of Liaoning, China, in rocks dated to the late Jurassic period, 161.0–160.5 million years ago.

Given the exquisite preservation of one of the animal’s fossils, “Anchiornis huxleyi” became the first dinosaur species for which almost the entire life coloration could be determined.

“Anchiornis huxleyi” was a small, paravian dinosaur with a triangular skull bearing several details in common with dromaeosaurids and troodontids. “Anchiornis” had very long legs, usually an indication that they were strong runners. However, the extensive leg feathers indicate that this may be a vestigial trait, as running animals tend to have reduced, not increased, hair or feathers on their legs. The forelimbs of “Anchiornis” were also very long, similar to archaeopterygids.

The first fossil was recovered from the Yaolugou locality, Jianchang County, western Liaoning, China; the second, at the Daxishan locality of the same area. The deposits are lake sediment, and are of uncertain age. Radiological measurements indicate an early Late Jurassic age for them, between 161 and 151 million years ago.

From Science News:

Under lasers, a feathered dino shows some skin

Geochemical fluorescence method illuminates Anchiornis soft tissue, but some remain skeptical

By Helen Thompson

2:40pm, March 20, 2017

What happens when you shoot lasers at a dinosaur fossil? Some chemicals preserved in the fossil glow, providing a nuanced portrait of the ancient creature’s bones, feathers and soft tissue such as skin.

Soft tissue is rarely preserved in fossils, and when it is, it can be easily obscured. A technique called laser-stimulated fluorescence “excites the few skin atoms left in the matrix, making them glow to reveal what the shape of the dinosaur actually looked like,” says Michael Pittman, a paleontologist at the University of Hong Kong.

Pittman and colleagues turned their lasers on Anchiornis, a four-winged dinosaur about the size of a pigeon with feathered arms and legs. It lived around 160 million years ago during the Jurassic Period. The researchers imaged nine specimens under laser light and used the photos to reconstruct a model of Anchiornis that shows an exceedingly birdlike body, the team writes March 1 in Nature Communications.

In the crooks of its elbows and wrists, the dinosaur had what looks like taut tissues called patagia, a feature in modern bird wings. “The wings of Anchiornis are reminiscent of the wings of some living gliding and soaring birds,” Pittman says. Plus, the images capture minute details like feather follicles and scales, and confirm some characteristics of Anchiornis long surmised by scientists: that it had drumstick-shaped legs, pads on the balls of its feet and a slim tail.

Still, it’s unclear what geochemicals are actually fluorescing in the fossils because the team didn’t perform any chemical analyses to determine the organic compounds or minerals present. “The images are very cool,” says Mary Schweitzer, a paleontologist at North Carolina State University in Raleigh. But, she cautions, a few hurdles remain, including testing fluorescence in different fossil types and verifying how skin glows under laser light in modern bird fossils.

Scientists normally rely on light-based methods and skeletal data to reconstruct the appearance of dinosaurs and other ancient creatures. Ultraviolet fluorescence works similarly to the new method, but the laser technique captures greater resolution. If laser-stimulated fluorescence lives up to its promise, it could help discern fossilized features that are invisible to the naked eye.

Functional form

Drawing from Anchiornis fossil specimens housed in a Chinese museum, researchers used measurements from laser-stimulated fluorescence images to create a more refined outline of the dinosaur’s body.

Major breakthrough in knowledge of dinosaur appearance: palaeontologist reconstructs feathered dinosaurs in the flesh with new technology: here.