Cambrian age sea star ancestor discovery


This June 2018 video is called The Evolution of Echinoderms.

From Ohio State University in the USA:

Scientists discover evolutionary link to modern-day sea echinoderms

Research team solves fossil mystery, identifies new species

May 2, 2019

Scientists at The Ohio State University have discovered a new species that lived more than 500 million years ago — a form of ancient echinoderm that was ancestral to modern-day groups such as sea cucumbers, sea urchins, sea stars, brittle stars and crinoids. The fossil shows a crucial evolutionary step by echinoderms that parallels the most important ecological change to have taken place in marine sediments.

The discovery, nearly 30 years in the making, was published recently in the Bulletin of Geosciences and provides a clue as to how creatures were able to make the evolutionary leap from living stuck to marine sediment grains — which were held together by gooey algae-like colonies, the original way that echinoderms lived — to living attached to hard, shelly surfaces, which is the way their modern-day descendants live now on the bottom of the ocean.

“It throws light on a critical time, not just in the evolution of organisms, but also in the evolution of marine ecosystems,” said Loren Babcock, co-author of the study and professor of earth sciences at Ohio State. “This represents a creature that clearly was making the leap from the old style of marine ecosystems in which sediments were stabilized by cyanobacterial mats, to what ultimately became the present system, with more fluidized sediment surfaces.”

The creature, a species of edrioasteroid echinoderm that Babcock and his researchers named Totiglobus spencensis, lived in the Cambrian Period — about 507 million years ago. (The Earth, for the record, is about 4.5 billion years old.) A family of fossil hunters discovered the fossil in shale of Spence Gulch, in the eastern part of Idaho, in 1992, and donated it to Richard Robison, a researcher at the University of Kansas and Babcock’s doctoral adviser. That part of the country is rich with fossils from the Cambrian period, Babcock said.

For years, the fossil puzzled both Babcock and Robison. But the mystery was solved a few years ago, when Robison’s fossil collection passed to Babcock after Robison’s retirement.

Once Babcock had the fossil in his lab, he and a visiting doctoral student, Rongqin Wen, removed layers of rock, exposing a small, rust-colored circle with numerous tiny plates and distinct arm-like structures, called ambulcra. Further study showed them that the animal attached itself to a small, conical shell of a mysterious, now-extinct animal called a hyolith using a basal disk — a short, funnel-like structure composed of numerous small calcite plates.

The discovery was a type of scientific poetry — years earlier, Babcock and Robison discovered the type of shell that this animal appeared to be attached to, and named it Haplophrentis reesei.

The edrioasteroid that Babcock and Wen discovered apparently lived attached to the upper side of the elongate-triangular hyolith shell, even as the hyolith was alive. They think a sudden storm buried the animals in a thick layer of mud, preserving them in their original ecological condition.

Echinoderms and hyoliths first appeared during the Cambrian Period, a time in Earth’s history when life exploded and the world became more biodiverse than it had ever been before. The earliest echinoderms, including the earliest edrioasteroids, lived by sticking to cyanobacterial mats — thick, algae-like substances that covered the Earth’s waters. And until the time of Totiglobus spencensis, echinoderms had not yet figured out how to attach to a hard surface.

“In all of Earth’s history, the Cambrian is probably the most important in the evolution of both animals and marine ecosystems, because this was a time when a more modern style of ecosystem was first starting to take hold,” Babcock said. “This genus of the species we discovered shows the evolutionary transition from being a ‘mat-sticker’ to the more advanced condition of attaching to a shelly substrate, which became a successful model for later species, including some that live today.”

In the early part of the Cambrian Period — which started about 538 million years ago — echinoderms likely lived on that algae-like substance in shallow seas that covered many areas of the planet. The algae, Babcock said, probably was not unlike the cyanobacterial mats that appear in certain lakes, including Lake Erie, each summer. But at some point, those algae-like substances became appealing food for other creatures, including prehistoric snails. During the Cambrian, as the population of snails and other herbivores exploded, the algae-like cyanobacterial mats began to disappear from shallow seas, and sediments became too physically unstable to support the animals — including echinoderms — that had come to rely on them.

Once their algae-like homes became food for other animals, Babcock said, echinoderms either had to find new places to live or perish.

Paleontologists knew that the creatures had somehow managed to survive, but until the Ohio State researchers’ discovery, they hadn’t seen much evidence that an echinoderm that lived this long ago had made the move from living stuck to cyanobacterial-covered sediment to living attached to hard surfaces.

“This evolutionary choice — to move from mat-sticker to hard shelly substrate — ultimately is responsible for giving rise to attached animals such as crinoids,” Babcock said. “This new species represents the link between the old lifestyle and the new lifestyle that became successful for this echinoderm lineage.”

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How some dinosaurs became birds, new research


This 2013 video says about itself:

Microraptor | Flying Dinosaur | Planet Dinosaur | BBC

Planet Dinosaur takes to skies, to investigate the perculiarities of winged dinosaurs. Microraptor had feathers for gliding but is it enough to escape from Sinornithosaurus?

From PLOS:

Running may have made dinosaurs’ wings flap before they evolved to fly

New evidence suggests that passive wing flapping may have arisen earlier than gliding flight

May 2, 2019

Before they evolved the ability to fly, two-legged dinosaurs may have begun to flap their wings as a passive effect of running along the ground, according to new research by Jing-Shan Zhao of Tsinghua University, Beijing, and his colleagues.

The findings, published in PLOS Computational Biology, provide new insights into the origin of avian flight, which has been a point of debate since the 1861 discovery of Archaeopteryx. While a gliding type of flight appears to have matured earlier in evolutionary history, increasing evidence suggests that active flapping flight may have arisen without an intermediate gliding phase.

To examine this key point in evolutionary history, Zhao and his colleagues studied Caudipteryx, the most primitive, non-flying dinosaur known to have had feathered “proto-wings.” This bipedal animal would have weighed around 5 kilograms and ran up to 8 meters per second.

First, the researchers used a mathematical approach called modal effective mass theory to analyze the mechanical effects of running on various parts of Caudipteryx’s body. These calculations revealed that running speeds between about 2.5 to 5.8 meters per second would have created forced vibrations that caused the dinosaur’s wings to flap.

Real-world experiments provided additional support for these calculations. The scientists built a life-size robot of Caudipteryx that could run at different speeds, and confirmed that running caused a flapping motion of the wings. They also fitted a young ostrich with artificial wings and found that running indeed caused the wings to flap, with longer and larger wings providing a greater lift force.

“Our work shows that the motion of flapping feathered wings was developed passively and naturally as the dinosaur ran on the ground,” Zhao says. “Although this flapping motion could not lift the dinosaur into the air at that time, the motion of flapping wings may have developed earlier than gliding.”

Zhao says that the next step for this research is to analyze the lift and thrust of Caudipteryx’s feathered wings during the passive flapping process.

Duck-billed dinosaurs, new research


This 2018 video is called Hadrosaurs Size Comparison.

From the University of Bristol in England:

Chewing versus sex in duck-billed dinosaurs

Evolutionary bursts led to weird and wonderful head crests

May 2, 2019

The duck-billed hadrosaurs walked the Earth over 90 million years ago and were one of the most successful groups of dinosaurs. But why were these 2-3 tonne giants so successful? A new study, published in Paleobiology, shows that their special adaptations in teeth and jaws and in their head crests were crucial, and provides new insights into how these innovations evolved.

Called the ‘sheep of the Mesozoic’ as they filled the landscape in the Late Cretaceous period, hadrosaurs walked on their hind legs and were known for their powerful jaws with multiple rows of extremely effective teeth. They also had hugely varied head display crests that signalled which species each belonged to and were used to attract mates. Some even trumpeted and tooted their special call, using nasal passages through the head crests.

Researchers from the Universities of Bristol and the Catalan Institute of Paleontology in Barcelona used a large database describing morphological variety in hadrosaur fossils and computational methods that quantify morphological variety and the pace of evolution.

Dr Tom Stubbs, lead author of the study and a researcher from Bristol’s School of Earth Sciences, said: “Our study shows that the unique hadrosaur feeding apparatus evolved fast in a single burst, and once established, showed very little change. In comparison, the elaborate display crests kept diversifying in several bursts of evolution, giving rise to the many weird and wonderful shapes.”

Professor Mike Benton, the study’s co-author from Bristol’s School of Earth Sciences, added, “Variation in anatomy can arise in many ways. We wanted to compare the two famous hadrosaur innovations, and by doing so, provide new insights into the evolution of this important dinosaur group. New numerical methods allow us to test these kinds of complex evolutionary hypotheses.”

“Our methods allowed us to identify branches on the hadrosaur evolutionary tree that showed rapid evolution in different parts of the skeleton,” said co-author Dr Armin Elsler. “When we looked at the jaws and teeth, we only saw fast evolution on a single branch at the base of the group. On the other hand, the bones that form the display crests showed multiple fast rate branches.”

Dr Albert Prieto-Márquez, co-author and world-leading expert on hadrosaurs from the Catalan Institute of Paleontology in Barcelona, added: “Our results suggest that evolution can be driven in different ways by natural selection and sexual selection. Hadrosaurs apparently fixed on a feeding apparatus that was successful and did not require massive modification to process their food. On the other hand, sexual selection drove the evolution of more complex crest shapes, and this is reflected by multiple evolutionary bursts.”

Dinosaur age millipede discovery in amber


This 2 May 2019 Burmanopetalum inexpectatum – a 99-million-year-old millipede trapped in amber.

From ScienceDaily:

Dwarfs under dinosaur legs: 99-million-year-old millipede discovered in Burmese amber

A 3D reconstruction of the fossil allowed for the description of an entirely new suborder

May 2, 2019

Summary: An 8.2-millimeter fossil millipede was discovered in Burmese amber. Having used new-age 3D X-ray microscopy, a research team confirmed this is the first fossil millipede of the entire order. The new species, despite having lived alongside the Cretaceous megafauna, is smaller than any of the extant members of its group. Because of its extraordinary morphology, it is described as a new suborder.

Even though we are led to believe that during the Cretaceous the Earth used to be an exclusive home for fearsome giants, including carnivorous velociraptors and arthropods larger than a modern adult human, it turns out that there was still room for harmless minute invertebrates measuring only several millimetres.

Such is the case of a tiny millipede of only 8.2 mm in length, recently found in 99-million-year-old amber in Myanmar. Using the latest research technologies, the scientists concluded that not only were they handling the first fossil millipede of the order (Callipodida) and also the smallest amongst its contemporary relatives, but that its morphology was so unusual that it drastically deviated from its contemporary relatives.

As a result, Prof. Pavel Stoev of the National Museum of Natural History (Bulgaria) together with his colleagues Dr. Thomas Wesener and Leif Moritz of the Zoological Research Museum Alexander Koenig (Germany) had to revise the current millipede classification and introduce a new suborder. To put it in perspective, there have only been a handful of millipede suborders erected in the last 50 years. The findings are published in the open-access journal ZooKeys.

To analyse the species and confirm its novelty, the scientists used 3D X-ray microscopy to ‘slice’ through the Cretaceous specimen and look into tiny details of its anatomy, which would normally not be preserved in fossils. The identification of the millipede also presents the first clue about the age of the order Callipodida, suggesting that this millipede group evolved at least some 100 million years ago. A 3D model of the animal is also available in the research article.

Curiously, the studied arthropod was far from the only one discovered in this particular amber deposit. On the contrary, it was found amongst as many as 529 millipede specimens, yet it was the sole representative of its order. This is why the scientists named it Burmanopetalum inexpectatum, where “inexpectatum” means “unexpected” in Latin, while the generic epithet (Burmanopetalum) refers to the country of discovery (Myanmar, formerly Burma).

Lead author Prof. Pavel Stoev says:

We were so lucky to find this specimen so well preserved in amber! With the next-generation micro-computer tomography (micro-CT) and the associated image rendering and processing software, we are now able to reconstruct the whole animal and observe the tiniest morphological traits which are rarely preserved in fossils. This makes us confident that we have successfully compared its morphology with those of the extant millipedes. It came as a great surprise to us that this animal cannot be placed in the current millipede classification. Even though their general appearance have remained unchanged in the last 100 million years, as our planet underwent dramatic changes several times in this period, some morphological traits in Callipodida lineage have evolved significantly.

Co-author Dr. Thomas Wesener adds:

“We are grateful to Patrick Müller, who let us study his private collection of animals found in Burmese amber and dated from the Age of Dinosaurs. His is the largest European and the third largest in the world collection of the kind. We had the opportunity to examine over 400 amber stones that contain millipedes. Many of them are now deposited at the Museum Koenig in Bonn, so that scientists from all over the world can study them. Additionally, in our paper, we provide a high-resolution computer-tomography images of the newly described millipede. They are made public through MorphBank, which means anyone can now freely access and re-use our data without even leaving the desk.”

Leading expert in the study of fossil arthropods Dr. Greg Edgecombe (Natural History Museum, London) comments:

“The entire Mesozoic Era — a span of 185 million years — has until now only been sampled for a dozen species of millipedes, but new findings from Burmese amber are rapidly changing the picture. In the past few years, nearly all of the 16 living orders of millipedes have been identified in this 99-million-year-old amber. The beautiful anatomical data presented by Stoev et al. show that Callipodida now join the club.”

Denisovans, first hominins of Tibetan Plateau


This 2 May 2019 video is called Tibetan Monk Finds 160,000 Year-Old DENISOVAN Mandible,

From the Max Planck Institute for Evolutionary Anthropology in Germany:

First hominins on the Tibetan Plateau were Denisovans

Denisovan mandible likely represents the earliest hominin fossil on the Tibetan Plateau

May 1, 2019

Summary: So far Denisovans were only known from a small collection of fossil fragments from Denisova Cave in Siberia. A research team now describes a 160,000-year-old hominin mandible from Xiahe in China. Using ancient protein analysis the researchers found that the mandible’s owner belonged to a population that was closely related to the Denisovans from Siberia. This population occupied the Tibetan Plateau in the Middle Pleistocene and was adapted to this low-oxygen environment long before Homo sapiens arrived in the region.

Denisovans — an extinct sister group of Neandertals — were discovered in 2010, when a research team led by Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) sequenced the genome of a fossil finger bone found at Denisova Cave in Russia and showed that it belonged to a hominin group that was genetically distinct from Neandertals. “Traces of Denisovan DNA are found in present-day Asian, Australian and Melanesian populations, suggesting that these ancient hominins may have once been widespread,” says Jean-Jacques Hublin, director of the Department of Human Evolution at the MPI-EVA. “Yet so far the only fossils representing this ancient hominin group were identified at Denisova Cave.”

Mandible from Baishiya Karst Cave

In their new study, the researchers now describe a hominin lower mandible that was found on the Tibetan Plateau in Baishiya Karst Cave in Xiahe, China. The fossil was originally discovered in 1980 by a local monk who donated it to the 6th Gung-Thang Living Buddha who then passed it on to Lanzhou University. Since 2010, researchers Fahu Chen and Dongju Zhang from Lanzhou University have been studying the area of the discovery and the cave site from where the mandible originated. In 2016, they initiated a collaboration with the Department of Human Evolution at the MPI-EVA and have since been jointly analysing the fossil.

While the researchers could not find any traces of DNA preserved in this fossil, they managed to extract proteins from one of the molars, which they then analysed applying ancient protein analysis. “The ancient proteins in the mandible are highly degraded and clearly distinguishable from modern proteins that may contaminate a sample,” says Frido Welker of the MPI-EVA and the University of Copenhagen. “Our protein analysis shows that the Xiahe mandible belonged to a hominin population that was closely related to the Denisovans from Denisova Cave.”

Primitive shape and large molars

The researchers found the mandible to be well-preserved. Its robust primitive shape and the very large molars still attached to it suggest that this mandible once belonged to a Middle Pleistocene hominin sharing anatomical features with Neandertals and specimens from the Denisova Cave. Attached to the mandible was a heavy carbonate crust, and by applying U-series dating to the crust the researchers found that the Xiahe mandible is at least 160,000 years old. Chuan-Chou Shen from the Department of Geosciences at National Taiwan University, who conducted the dating, says: “This minimum age equals that of the oldest specimens from the Denisova Cave.”

“The Xiahe mandible likely represents the earliest hominin fossil on the Tibetan Plateau,” says Fahu Chen, director of the Institute of Tibetan Research, CAS. These people had already adapted to living in this high-altitude low-oxygen environment long before Homo sapiens even arrived in the region. Previous genetic studies found present-day Himalayan populations to carry the EPAS1 allele in their genome, passed on to them by Denisovans, which helps them to adapt to their specific environment.

“Archaic hominins occupied the Tibetan Plateau in the Middle Pleistocene and successfully adapted to high-altitude low-oxygen environments long before the regional arrival of modern Homo sapiens,” says Dongju Zhang. According to Hublin, similarities with other Chinese specimens confirm the presence of Denisovans among the current Asian fossil record. “Our analyses pave the way towards a better understanding of the evolutionary history of Middle Pleistocene hominins in East Asia.”

European Union makes Tilos dwarf elephants invisible


Tilos dwarf elephant reconstruction

This photo shows the reconstruction of a prehistoric dwarf elephant, found on Tilos island in Greece.

From the Aegean Islands site in Greece:

Tilos is a gem of the Dodecanese islands, rich in both culture and natural beauty, and its breathtaking views represent much of its charm. From peculiar wildlife and spectacular flowers to magnificent historic villages and pure-white secluded beaches, there’s absolutely nothing you can’t find on the dazzling little island.

If you’re searching for an adventure on a lost island, how about a peek at the fossilized bones of dwarf elephants? For those interested into the island’s past, they will truly fascinate you.

On the left hand side of the road to Megalo Chorio is the Charkadio Cave where the remains of dwarf elephants were discovered in 1971. The cave is not open to the public as excavations are still not completed. In this cave also neolithic ceramics and tools made of stone have been found, just as deer bones from a much older date than the bones of the elephants (about 140.000 BC).

… Nearby the entrance, you will see the construction of a new museum which will eventually contain the finds inside the cave.

… These dwarf elephants lived on the island until about 4000 BC.

The bones of thousands of elephants have been found in the cave and this discovery was one of the first to establish the existence of elephants in Europe.

Wikipedia also mentions the dwarf elephants of Tilos, and the exhibition about them.

On 1 May 2019, we saw the brand new paleontological museum, where the elephant fossils and other finds were supposed to go. However, the building was very empty and very closed.

That evening, we heard why. The European Union told Tilos that the museum was only allowed to open if visitors would pay at least six euros. Tilos did not want that, as that would mean employing a cashier whose wages would cost more than incoming entry fees. As not that many tourists come to Tilos; the museum is a bit in the middle of nowhere; and not many tourists and Tilos inhabitants would want to pay six euros to see the small museum. Though more would come if the museum would be free.

According to the European Union, a museum should be a business out to make a profit. European Union bureaucrats are apparently better at reading the novels of pro-capitalist propagandist and Donald Trump favourite Ayn Rand than at reading books on paleontology or other sciences. Museums should be about scientific research and informing the public about science for free, not about profits.

After this 1 May 2019 elephant interlude, the blog posts on Tilos will resume in proper chronological order. So, stay tuned!

Mammals, from dinosaur age till now


This 2008 video says about itself:

On the Science Channel’s “Mammals vs. Dinos”: although most small prehistoric mammals were nocturnal, the Repenomamus hunted by day and preyed on small dinosaurs which was a sign of the evolution of mammals.

From the University of Washington in the USA:

Flowering plants, new teeth and no dinosaurs: New study sheds light on the rise of mammals

May 1, 2019

A new study published April 30 in the Proceedings of the National Academy of Sciences identified three factors critical in the rise of mammal communities since they first emerged during the Age of Dinosaurs: the rise of flowering plants, also known as angiosperms; the evolution of tribosphenic molars in mammals; and the extinction of non-avian dinosaurs, which reduced competition between mammals and other vertebrates in terrestrial ecosystems.

Previously, mammals in the Age of Dinosaurs were thought to be a relatively small part of their ecosystems and considered to be small-bodied, nocturnal, ground-dwelling insectivores. According to this long-standing theory, it wasn’t until the K-Pg mass extinction event about 66 million years ago, which wiped out all non-avian dinosaurs, that mammals were then able to flourish and diversify. An astounding number of fossil discoveries over the past 30 years has challenged this theory, but most studies looked only at individual species and none has quantified community-scale patterns of the rise of mammals in the Mesozoic Era.

Co-authors are Meng Chen, a University of Washington alumnus and current postdoctoral researcher at Nanjing University; Caroline Strömberg, a University of Washington biology professor and curator of paleobotany at the UW’s Burke Museum of Natural History & Culture; and Gregory Wilson, a UW associate professor of biology and Burke Museum curator of vertebrate paleontology. The team created a Rubik’s Cube-like structure identifying 240 “eco-cells” representing possible ecological roles of mammals in a given ecospace. These 240 eco-cells cover a broad range of body size, dietary preferences, and ways of moving of small-bodied mammals. When a given mammal filled a certain type of role or eco-cell, it filled a spot in the ‘Rubik’s Cube.’ This method provides the first comprehensive analysis of evolutionary and ecological changes of fossil mammal communities before and after K-Pg mass extinction.

“We cannot directly observe the ecology of extinct species, but body size, dietary preferences and locomotion are three aspects of their ecology that can be relatively easily inferred from well-preserved fossils,” said Chen. “By constructing the ecospace using these three ecological aspects, we can visually identify the spots filled by species and calculate the distance among them. This allows us to compare the ecological structure of extinct and extant communities even though they don’t share any of the same species.”

The team analyzed living mammals to infer how fossil mammals filled roles in their ecosystems. They examined 98 small-bodied mammal communities from diverse biomes around the world, an approach that has not been attempted at this scale. They then used this modern-day reference dataset to analyze five exceptionally preserved mammal paleocommunities — two Jurassic Period and two Cretaceous Period communities from northeastern China, and one Eocene Epoch community from Germany. Usually Mesozoic Era mammal fossils are incomplete and consist of fragmentary bones or teeth. Using these remarkably preserved fossils enabled the team to infer ecology of these extinct mammal species, and look at changes in mammal community structure during the last 165 million years.

The team found that, in current communities of present-day mammals, ecological richness is primarily driven by vegetation type, with 41 percent of small mammals filling eco-cells compared to 16 percent in the paleocommunities. The five mammal paleocommunities were also ecologically distinct from modern communities and pointed to important changes through evolutionary time. Locomotor diversification occurred first during the Mesozoic, possibly due to the diversity of microhabitats, such as trees, soils, lakes and other substrates to occupy in local environments. It wasn’t until the Eocene that mammals grew larger and expanded their diets from mostly carnivory, insectivory and omnivory to include more species with diets dominated by plants, including fruit. The team determined that the rise of flowering plants, new types of teeth and the extinction of dinosaurs likely drove these changes.

Before the rise of flowering plants, mammals likely relied on conifers and other seed plants for habitat, and their leaves and possibly seeds for food. By the Eocene, flowering plants were both diverse and dominant across forest ecosystems. Flowering plants provide more readily available nutrients through their fast-growing leaves, fleshy fruits, seeds and tubers. When becoming dominant in forests, they fundamentally changed terrestrial ecosystems by allowing for new modes of life for a diversity of mammals and other forest-dwelling animals, such as birds.

“Flowering plants really revolutionized terrestrial ecosystems,” said Strömberg. “They have a broader range of growth forms than all other plant groups — from giant trees to tiny annual herbs — and can produce nutrient-rich tissues at a faster rate than other plants. So when they started dominating ecosystems, they allowed for a wider variety of life modes and also for much higher ‘packing’ of species with similar ecological roles, especially in tropical forests.”

Tribosphenic molars — complex multi-functional cheek teeth — became prevalent in mammals in the late Cretaceous Period. Mutations and natural selection drastically changed the shapes of these molars, allowing them to do new things like grinding. In turn, this allowed small mammals with these types of teeth to eat new kinds of foods and diversify their diets.

Lastly, the K-Pg mass extinction event that wiped out all dinosaurs except birds 66 million years ago provided an evolutionary and ecological opportunity for mammals. Small body size is a way to avoid being eaten by dinosaurs and other large vertebrates. The mass extinction event not only removed the main predators of mammals, but also removed small dinosaurs that competed with mammals for resources. This ecological release allowed mammals to grow into larger sizes and fill the roles the dinosaurs once had.

“The old theory that early mammals were held in check by dinosaurs has some truth to it,” said Wilson. “But our study also shows that the rise of modern mammal communities was multifaceted and depended on dental evolution and the rise of flowering plants.”