Herbivorous dinosaurs, new research


This May 2018 video is called 10 LARGEST Herbivorous Dinosaurs That Ever Lived.

From ScienceDaily:

Dull teeth, long skulls, specialized bites evolved in unrelated plant-eating dinosaurs

December 5, 2019

Herbivorous dinosaurs evolved many times during the 180 million-year Mesozoic era, and while they didn’t all evolve to chew, swallow, and digest their food in the same way, a few specific strategies appeared time and time again. An investigation of the skulls of 160 non-avian dinosaurs revealed the evolution of common traits in the skulls and teeth of plant-eating members of otherwise very different families of these extinct reptiles. These new examples of convergent evolution in plant-eating dinosaurs appear December 5 in the journal Current Biology.

“People often think of dinosaurs as a swansong for extinction or that they were a failed species. But they were actually extremely successful in terms of how different species’ anatomies evolved — particularly in herbivores,” says co-senior author David J. Button (@ItsDavidButton), a paleontologist at the Natural History Museum, London.

By looking at herbivorous and carnivorous dinosaur skulls, Button and co-senior author Lindsay Zanno, a professor at North Carolina State University and the head of paleontology at the North Carolina Museum of Natural Sciences, found that while there are many ways for dinosaurs that eat similar foods to evolve, some traits reappear during evolution, even in unrelated species.

Herbivorous dinosaurs came in all shapes and sizes. Some exhibited dull, flat teeth like horses, while others had beaked faces like tortoises; some developed towering necks like giraffes, while others mimicked the short and stout build of a rhino. “Nonetheless, we see the evolution of common traits in the skull between these otherwise very different herbivorous dinosaur groups,” explains Button.

“For example, both the ostrich-like ornithomimosaurs and giant titanosaurs independently evolved elongate skulls and weaker bites, whereas the horned ceratopsians and gazelle-like ornithopods sported more powerful jaws and grinding teeth,” he says. These are results of convergent evolution, where adaptation to a diet of plants led to the evolution of common characters in different dinosaur groups.

The researchers hypothesized that some traits would be most common in plant-eaters. Slow-moving dinosaurs with small heads and dull teeth would likely have a difficult time wrapping their jaws around the neck of another dinosaur, in the way a carnivore like the Tyrannosaurus is thought to have done with ease. Instead, eating plants poses other challenges, such as grinding down tough plant stems.

“There’s a tradeoff between biting speed and biting efficiency,” says Button. “If you’re a herbivorous animal, you don’t really need speed because plants don’t move very fast.”

Some of the results of this functional analysis surprised the researchers, however. That was the case when investigating the eating habits of ankylosaurs, armored, armadillo-like plant-eating dinosaurs with small teeth and a large stomach cavity. Researchers previously thought dinosaurs with these traits usually swallowed their food nearly whole and let their gut break it down. “In our results, we found that ankylosaurs actually may have chewed their food more thoroughly than is often thought. So, that was interesting,” says Button.

In the future, Button and Zanno hope to look at the entire skeleton of herbivorous dinosaurs for similar, reoccurring traits. They also plan to expand this work to better understand predominate traits in carnivores, though Button admits plant-eaters will always be his favorite dinosaurs to study.

“People think that carnivorous dinosaurs are super exciting and cool because they run fast, and kill stuff,” he says. “But I think the plant-eating dinosaurs evolved in much more interesting and sophisticated ways. That’s what makes this work so exciting.”

Horseshoe crab eyes, 400 million years old


This July 2018 video is called What If The Jaekelopterus rhenaniae Didn’t Go Extinct?

From the University of Cologne in Germany:

Compound eyes: The visual apparatus of today’s horseshoe crabs goes back 400 million years

December 3, 2019

The eyes of the extinct sea scorpion Jaekelopterus rhenaniae have the same structure as the eyes of modern horseshoe crabs (Limulidae). The compound eyes of the giant predator exhibited lens cylinders and concentrically organized sensory cells enclosing the end of a highly specialized cell. This is the result of research Dr Brigitte Schoenemann, professor of zoology at the Institute of Biology Didactics at the University of Cologne, conducted with an electron microscope. Cooperation partners in the project were Dr Markus Poschmann from the Directorate General of Cultural Heritage RLP, Directorate of Regional Archaeology/Earth History and Professor Euan N.K. Clarkson from the University of Edinburgh. The results of the study ‘Insights into the 400 million-year-old eyes of giant sea scorpions (Eurypterida) suggest the structure of Palaeozoic compound eyes’ have been published in the journal Scientific Reports — Nature.

The eyes of modern horseshoe crabs consist of compounds, so-called ommatidia. Unlike, for example, insects that have compound eyes with a simple lens, the ommatidia of horseshoe crabs are equipped with a lens cylinder that continuously refracts light and transmits it to the sensory cells.

These sensory cells are grouped in the form of a rosette around a central light conductor, the rhabdom, which is part of the sensory cells and converts light signals into nerve signals to transmit them to the central nervous system. At the centre of this ‘light transmitter’ in horseshoe crabs is a highly specialized cell end, which can connect the signals of neighbouring compounds in such a way that the crab perceives contours more clearly. This can be particularly useful in conditions of low visibility under water. In the cross-section of the ommatidium, it is possible to identify the end of this specialized cell as a bright point in the centre of the rhabdom.

Brigitte Schoenemann used electron microscopes to examine fossil Jaekelopterus rhenaniae specimens to find out whether the compound eyes of the giant scorpion and the related horseshoe crabs are similar or whether they are more similar to insect or crustacean eyes. She found the same structures as in horseshoe crabs. Lens cylinders, sensory cells and even the highly specialized cells were clearly discernible.

‘This bright spot belongs to a special cell that only occurs in horseshoe crabs today, but apparently already existed in eurypterida,’ explained Schoenemann. ‘The structures of the systems are identical. It follows that very probably this sort of contrast enhancement already evolved more than 400 million years ago,’ she added. Jaekelopterus most likely hunted placoderm[i fish]. Here, its visual apparatus was clearly an advantage in the murky seawater.

Sea scorpions, which first appeared 470 million years ago, died out about 250 million years ago, at the end of the Permian age — along with about 95 percent of all marine life. Some specimens were large oceanic predators, such as Jaekelopterus rhenaniae. It reached a length of 2.5 meters and belonged to the family of eurypterida, the extinct relatives of the horseshoe crab. Eurypterida are arthropods, which belong to the subphylum Chelicerata, and are therefore related to spiders and scorpions.

Among the arthropods there are two large groups: mandibulates (crustaceans, insects, trilobites) and chelicerates (arachnid animals such as sea scorpions). In recent years, Schoenemann has been able to clarify the eye structures of various trilobite species and to make decisive contributions to research into the evolution of the compound eye. ‘Until recently, scientists thought that soft tissues do not fossilize. Hence these parts of specimens were not examined until not so long ago’, she concluded.

The new findings on the eye of the sea scorpion are important for the evolution of the compound eyes not only of chelicerates, but also for determining the position of sea scorpions in the pedigree of these animals and for the comparison with the eyes of the related group of mandibulates.

Brontosaurus dinosaur video


This 1 December 2019 video says about itself:

Brontosaurus – The Story of the Thunder Lizard

The history of Brontosaurus is one of the most fascinating tales in palaeontology, full of controversies, missing heads and charismatic yet unpleasant people.

How birds learnt to fly, new research


This 2011 video is called Peacock Dance Display – Peacocks Opening Feathers HD & Bird Sound.

From ScienceDaily:

Researchers study chickens, ostriches, penguins to learn how flight feathers evolved

November 27, 2019

If you took a careful look at the feathers on a chicken, you’d find many different forms within the same bird — even within a single feather. The diversity of feather shapes and functions expands vastly when you consider the feathers of birds ranging from ostriches to penguins to hummingbirds. Now, researchers reporting in the journal Cell on November 27 have taken a multidisciplinary approach to understanding how all those feathers get made.

“We always wonder how birds can fly and in different ways,” says corresponding author Cheng-Ming Chuong of the University of Southern California, Los Angeles. “Some soar like eagles, while others require rapid flapping of wings like hummingbirds.” Some birds, including ostriches and penguins, don’t fly at all.

“Such differences in flight styles are largely due to the characteristics of their flight feathers,” Chuong adds. “We wanted to learn how flight feathers are made so we can understand nature better and learn principles of bioinspired architecture.”

In the new study, the researchers put together a multidisciplinary team to look at feathers in many different ways, from their biophysical properties to the underlying molecular biology that allows their formation from stem cells in the skin. They examined the feathers of flightless ostriches, short-distance flying chickens, soaring ducks and eagles, and high-frequency flying sparrows. They studied the extremes by including hummingbirds and penguins. To better understand how feathers have evolved and changed over evolutionary time, the team also looked to feathers that are nearly 100 million years old, found embedded and preserved in amber in Myanmar.

Based on their findings, the researchers explain that feathers’ modular structure allowed birds to adapt over evolutionary time, helping them to succeed in the many different environments in which birds live today. Their structure also allows for the specialization of feathers in different parts of an individual bird’s body.

The flight feather is made of two highly adaptable architectural modules: the central shaft, or rachis, and the peripheral vane. The rachis is a composite beam made of a porous medulla that keeps feathers light surrounded by a rigid cortex that adds strength. Their studies show that these two components of the rachis allow for highly flexible designs that enabled to fly or otherwise get around in different ways. The researchers also revealed the underlying molecular signals, including Bmp and Ski, that guide the development of those design features.

Attached to the rachis is the feather vane. The vane is the part of the feather made up of many soft barbs that zip together. The researchers report that the vane develops using principles akin to paper cutting. As such, a single epithelial sheet produces a series of diverse, branched designs with individual barbs, each bearing many tiny hooklets that hold the vane together into a plane using a Velcro-like mechanism. Their studies show that gradients in another signaling pathway (Wnt2b) play an important role in the formation of those barbs.

To look back in time, the researchers studied recently discovered amber fossils, allowing them to explore delicate, three-dimensional feather structures. Their studies show that ancient feathers had the same basic architecture but with more primitive characteristics. For instance, adjacent barbs formed the vane with overlapping barbules, without the Velcro-like, hooklet mechanism found in living birds.

“We’ve learned how a simple skin can be transformed into a feather, how a prototypic feather structure can be transformed into downy, contour, or flight feathers, and how a flight feather can be modulated to adapt to different flight modes required for different living environments,” Chuong says. “In every corner and at different morphological scales, we were amazed at how the elegant adaption of the prototype architecture can help different birds to adapt to different new environments.”

The researchers say that, in addition to helping to understand how birds have adapted over time, they hope these bioinspired architectural principles they’ve uncovered can be useful in future technology design. They note that composite materials of the future could contribute toward the construction of light but robust flying drones, durable and resilient wind turbines, or better medical implants and prosthetic devices.

Team co-leader and biophysicist Wen Tau Juan of the Integrative Stem Cell Center of China Medical University Hospital, Taiwan, has already begun to explore the application of feather-inspired architectural principles in bio-material design. The team also hopes to learn even more about the molecular signals that allow the formation of such complex feather structures from epidermal stem cells that all start out the same.

Springtail fossil discovery in Dominican Republic


This is a 2010 video about springtails taken from the BBC’s Life in the Undergrowth documentary series.

From the New Jersey Institute of Technology in the USA:

16-million-year-old fossil shows springtails hitchhiking on winged termite

November 25, 2019

Summary: A newly reported, 16-million-year-old fossil is shedding light on how a group of tiny arthropods may have traversed the globe — by hitchhiking.

When trying to better the odds for survival, a major dilemma that many animals face is dispersal — being able to pick up and leave to occupy new lands, find fresh resources and mates, and avoid intraspecies competition in times of overpopulation.

For birds, butterflies and other winged creatures, covering long distances may be as easy as the breeze they travel on. But for soil-dwellers of the crawling variety, the hurdle remains: How do they reach new, far-off habitats?

For one group of tiny arthropods called springtails (Collembola), a recent fossil discovery now suggests their answer to this question has been to piggyback on the dispersal abilities of others, literally.

In findings published in BMC Evolutionary Biology, researchers at the New Jersey Institute of Technology (NJIT) and Museum national d’Histoire naturelle have detailed the discovery of an ancient interaction preserved in 16-million-year-old amber from the Dominican Republic: 25 springtails attached to, and nearby, a large winged termite and ant from the days of the early Miocene.

The fossil exhibits a number of springtails still attached to the wings and legs of their hosts, while others are preserved as if gradually floating away from their hosts within the amber. Researchers say the discovery highlights the existence of a new type of hitchhiking behavior among wingless soil-dwelling arthropods, and could be key to explaining how symphypleonan springtails successfully achieved dispersal worldwide.

“The existence of this hitchhiking behavior is especially exciting given the fact that modern springtails are rarely described as having any interspecfic association with surrounding animals,” said Ninon Robin, the paper’s first author whose postdoctoral research at NJIT’s Department of Biological Sciences was funded by the Fulbright Program of the French-American Commission. “This finding underscores how important fossils are for telling us about unsuspected ancient ecologies as well as still ongoing behaviors that were so far simply overlooked.”

Today, springtails are among the most common arthropods found in moist habitats around the world. Most springtails possess a specialized appendage under their abdomen they use to “spring” away in flea-like fashion to avoid predation. However, this organ is not sufficient for traversing long distances, especially since most springtails are unable to survive long in dry areas.

The hitchhikers the researchers identified belong to a lineage of springtails found today on every continent, known as Symphypleona, which they say may have been “pre-adapted” to grasping on to other arthropods through prehensile antennae.

Because springtails would have encountered such winged termites and ants frequently due to their high abundance during the time of the preservation, these social insects may have been their preferred hosts for transportation.

“Symphypleonan springtails are unusual compared to other Collembola in that they have specialized antennae that are used in mating courtship,” said Phillip Barden, assistant professor of biology at NJIT and the study’s principal investigator. “This antennal anatomy may have provided an evolutionary pathway for grasping onto other arthropods. In this particular fossil, we see these specialized antennae wrapping around the wings and legs of both an ant and termite. Some winged ants and termites are known to travel significant distances, which would greatly aid in dispersal.”

Barden says that the discovery joins other reports from the Caribbean and Europe of fossil springtails attached to a beetle, a mayfly and a harvestman in amber, which together suggest that this behavior may still exist today.

Barden notes that evidence of springtail hitchhiking may not have been captured in such high numbers until now due to the rarity of such a fossilized interaction, as well as the nature of modern sampling methods for insects, which typically involves submersion in ethanol for preservation.

“Because it appears that springtails reflexively detach from their hosts when in danger, evidenced by the detached individuals in the amber, ethanol would effectively erase the link between hitchhiker and host,” said Barden. “Amber derives from fossilized sticky tree resin and is viscous enough that it would retain the interaction. … Meaning, sometimes you have to turn to 16-million-year-old amber fossils to find out what might be happening in your backyard.”

Styracosaurus dinosaurs, new discovery


This May 2018 video says about itself:

This time, probably the second-most-popular ceratopsid, Styracosaurus–and by extension Rubeosaurus. Hope you’re ready to learn about the environmental and social forces that shaped this giant pig-antelope-bird. …and also what a parietal spike is.

From the University of Alberta in Canada:

Dinosaur skull turns paleontology assumptions on their head

University of Alberta paleontologists uncover spiky skull–and overturn long-standing assumptions in identifying horned dinosaurs

November 25, 2019

A team of researchers at the University of Alberta has unearthed a well-preserved Styracosaurus skull — and its facial imperfections have implications for how paleontologists identify new species of dinosaurs.

The skull was discovered by Scott Persons in 2015, then a graduate student in the Department of Biological Sciences, during an expedition in the badlands northwest of Dinosaur Provincial Park.

Nicknamed Hannah, the dinosaur was a Styracosaurus — a horned dinosaur over five metres in length with a fan of long horns. UAlberta paleontologists led by Robert Holmes, professor in the Department of Biological Sciences, have learned much from those horns — because they aren’t symmetrical.

“When parts of one side of the skull were missing, paleontologists have assumed that the missing side was symmetrical to the one that was preserved,” explained Persons. “Turns out, it isn’t necessarily. Today, deer often have left and right antlers that are different in terms of their branching patterns. Hannah shows dramatically that dinosaurs could be the same way.”

The differences in the skull’s left and right halves are so extreme that had the paleontologists found only isolated halves, they might have concluded that they belong to two different species

“The skull shows how much morphological variability there was in the genus,” said Holmes. Like the antlers of modern deer and moose, Hannah shows that the pattern of dinosaur horns could vary significantly — meaning some fossils that were once assumed to be unique species will have to be reevaluated.

Tradition dictates that the person who finds an important dinosaur specimen gets to give it a nickname. “Hannah the dinosaur is named after my dog,” explained Persons, now a professor and museum curator at the College of Charleston. “She’s a good dog, and I knew she was home missing me while I was away on the expedition.”

Despite the nickname, paleontologists have no way of knowing if the dinosaur was female. But they have learned other details from the skull — from a partnership with researchers in the Faculty of Engineering.

“Ahmed Qureshi and graduate student Baltej Rupal in the Faculty of Engineering assisted us in performing a 3D laser scan of the skull,” said Persons. “That let our publication to include a digital reconstruction, allowing scientists all over the world to download the 3D model and inspect it in detail.”

“This is the future of paleontological collections: digital dinosaurs.”