Insects ate dinosaurs’ feathers


This 29 October 2018 video says about itself:

From ancient antagonistic arachnids … to the feathered tails of dinosaurs … Here are 13 of the most ancient animals preserved in amber

#13 Ant vs Wasp … Forever

Some amber unearthed in Myanmar in 2012 revealed an epic struggle frozen in time for upwards of 100 million years (possibly more). A spider was in the midst of attacking a wasp that had become tangled in its web … the only such fossil found thus far to depict such an arachnid attack. It would have been the wasp’s worst nightmare to see the spider approaching it … and since the tree resin covered and captured them both, the nightmare never ended.

#12 Immortal Combat

Two insects found in an exquisite piece of amber kind of serve to epitomize the idea of ant warfare. Two species of ants were revealed to have been locked in combat for over 100 million years. According to researchers, the minute critters were so focused on waging war on one another that they just didn’t notice when tree resin was covering them … which of course fossilized over time. Since the critters’ jaws were still locked together, it’s possible that the two ants were fighting over a food source … or caught up in the midst of a nest being raided. Researchers say that the specimen located in Myanmar might provide the clearest evidence to date regarding insects displaying advanced social behaviors … although in this case, maybe it would be ‘antisocial behaviors’.

By Sofie Bates, December 10, 2019, at 11:00 am:

Licelike insects munched on dinosaur feathers around 100 million years ago

Fossils in amber push the origin of feather-feeding insects back over 50 million years

Feathered dinosaurs, including early birds, may have dealt with pests similar to lice around 100 million years ago.

A newfound ancient insect species, dubbed Mesophthirus engeli, was found preserved with dinosaur feathers in two pieces of Myanmar amber dating to the mid-Cretaceous Period (SN: 7/24/14).

The fossils are the earliest evidence found of insects feeding on feathers, researchers report December 10 in Nature Communications. The previous record-holder was a fossilized louse from roughly 44 million years ago, says Taiping Gao, a paleoentomologist from Capital Normal University in Beijing.

M. engeli looks somewhat like modern lice, with teeth and a thick, wingless body. The insects also have anatomical traits seen in other ectoparasites — those that live outside of their host’s body. In one piece of amber that Gao and colleagues analyzed under a microscope, the team found nine insects on or near a feather. That feather had damage holes toward its end, but not near its base — a pattern that also occurs when lice chomp on modern birds’ feathers.

Modern birds replace old or damaged feathers through molting, says Luis Chiappe, a paleontologist at the Natural History Museum of Los Angeles County who specializes in birds. The new findings show that parasite–host relationships that could’ve damaged feathers began at least 100 million years ago, he says, and could be one reason why birds evolved to molt.

Dinosaur age mammals´ ears, new discovery


Origolestes lii, shown in the foreground in this artist’s rendition, was a shrew-sized mammal that lived about 123 million years ago in an ecosystem known as the Jehol Biota in what’s now China. By Chuang Zhao

By Carolyn Gramling, December 6, 2019:

An ancient critter may shed light on when mammals’ middle ear evolved

How early the hammer, anvil and stirrup arose has been hard to pin down

Exceptionally preserved skulls of a mammal that lived alongside the dinosaurs may be offering scientists a glimpse into the evolution of the middle ear.

The separation of the three tiny middle ear bones — known popularly as the hammer, anvil and stirrup — from the jaw is a defining characteristic of mammals. The evolutionary shift of those tiny bones, which started out as joints in ancient reptilian jaws and ultimately split from the jaw completely, gave mammals greater sensitivity to sound, particularly at higher frequencies (SN: 3/20/07). But finding well-preserved skulls from ancient mammals that can help reveal the timing of this separation is a challenge.

Now, scientists have six specimens — four nearly complete skeletons and two fragmented specimens — of a newly described, shrew-sized critter dubbed Origolestes lii that lived about 123 million years ago. O. lii was part of the Jehol Biota, an ecosystem of ancient wetlands-dwellers that thrived between 133 million and 120 million years ago in what’s now northeastern China.

The skulls on the nearly complete skeletons were so well-preserved that they were able to be examined in 3-D, say paleontologist Fangyuan Mao of the Chinese Academy of Sciences in Beijing and colleagues. That analysis suggests that O. lii’s middle ear bones were fully separated from its jaw, the team reports online December 5 in Science.

Fossils from an older, extinct line of mammals have shown separated middle ear bones, but this newfound species would be the first of a more recent lineage to exhibit this evolutionary advance.

O. lii apparently moved its jaw both in side-to-side and in rolling motions as it chewed. Such chewing ability, the team says, may have played a role in the evolutionary separation of the jaw and middle ear bones.

“This paper describes a spectacular fossil,” says vertebrate paleontologist Zhe-Xi Luo of the University of Chicago, who was not involved in the new study. But he’s not convinced that O. lii represents an evolutionary leap forward in mammalian ear evolution.

Luo notes that O. lii is closely related to the mammal genus Maotherium, which lived around the same time and in roughly the same location. In Science in July, Luo and colleagues reported that a new analysis of Maotherium revealed that its middle ear bones were still connected to its jawbones by a strip of cartilage (SN: 7/18/19).

That finding, Luo says, was expected. Maotherium is well-known as a transitional organism, in which the middle ear bones had begun to rotate away from the jaw but were still loosely connected by that cartilage. There are numerous branches and twigs on the mammal family tree, Luo says, and evolution occurred at a different pace on them. But, he says, it’s unlikely that O. lii would have had separated ear bones when Maotherium didn’t, given the pair’s close positioning on the tree.

Luo says he also doesn’t find the study’s evidence that the separation was complete in O. lii convincing. Three of the four skulls in the study were missing all or part of the middle ear, and the gap between the middle ear bones and jaw in the fourth skull may have been a break that occurred during fossilization, he adds.

However, the new study’s researchers reject this idea. “It’s common that different interpretations may exist for a discovery in paleontology,” says vertebrate paleontologist Jin Meng of the American Museum of Natural History in New York, a co-author of the study.

But, Meng says, none of the ear bones or the cartilage in any of the skulls show fractured or broken edges. That, he says, suggests that these features were already separated in the animals before their demise.

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.”

Dinosaur age snake discovery


This 22 November 2019 video says about itself:

On very rare occasions, an exceptional fossil is unearthed that provides an extraordinary glimpse into the evolution of a group of organisms.

This time, it is the beautifully preserved skull of an ancient snake with rear limbs, Najash rionegrina. Our study of this fossil has been published in the journal Science Advances.

This and other new fossils help answer longstanding questions on the origins of snakes, such as how they lost their limbs and evolved their highly specialized skulls.

Fossil history

Najash rionegrina is named after the legged biblical snake Nahash (Hebrew for snake), and the Río Negro Province in Argentina, where the fossils were discovered. Fossils of Najash are about 95 million years old, and were first described in Nature from a fragmentary skull and partial body skeleton that preserved robust rear limbs.

This rear-limbed fossil snake garnered a great deal of media interest as it followed earlier reports of fossil marine snakes with rear limbs. What made Najash unique was that it was a terrestrial snake living in a desert, not an aquatic snake living in the ocean. In addition, the fossils were not compressed flat by the weight of overlying sediments, and so they were preserved in three dimensions, unlike the fossil marine snakes.

Unfortunately, that first description of Najash relied on a very fragmentary skull. Scholars of snake evolution were left to guess at what the head of these ancient animals might have looked like.

We know from their shared anatomy that snakes evolved from lizards. We also know that the skulls of snakes have been key to their successful and highly specialized feeding adaptations. New Najash fossil skulls would be highly informative on the pattern of snake skull evolution.

The new discovery

It was a hot day in February of 2013 when Fernando Garberoglio, then an undergraduate palaeontology student from the Universidad de Buenos Aires, went on his first field trip to the La Buitrera Paleontological Area in northern Patagonia, Argentina. With him were two palaeontologists: Sebastián Apesteguía, from the Universidad Maimónides, and Guillermo Rougier, from the University of Louisville.

Looking for fossil vertebrates is an act of patient, painstaking discovery. It requires you to be close to the ground, scanning the grit, pebbles, rocks and sediments for a sign of bone. You must pick up each piece, inspect it closely, put it down and then repeat, hour after hour. At La Buitrera, you are scorched by the hot sun, pelted by driving rain and frozen by chilly Andean winds.

But it’s all worth it. Particularly when, as happened to Garberoglio, he finally picked up a pebble, only a few centimetres long, to find a small, ancient, bony face staring back at him.

From the University of Alberta in Canada:

An ancient snake’s cheekbone sheds light on evolution of modern snake skulls

100-million-year old legged snake fossil provides critical insight into how the heads of modern snakes evolved

November 20, 2019

New research from a collaboration between Argentinian and University of Alberta palaeontologists adds a new piece to the puzzle of snake evolution.

The researchers examined a strikingly well-preserved fossil of the rear-limbed snake Najash rionegrina, found in Argentina. The study shows that nearly 100 million years ago, these legged snakes still had a cheekbone — also known as a jugal bone — that has all but disappeared in their modern descendants.

“Our findings support the idea that the ancestors of modern snakes were big-bodied and big-mouthed — instead of small burrowing forms as previously thought,” explained Fernando Garberoglio, from the Fundación Azara at Universidad Maimónides, in Buenos Aires, Argentina and lead author on the study. “The study also reveals that early snakes retained their hindlimbs for an extended period of time before the origin of modern snakes which are for the most part, completely limbless.”

For decades, paleontologists’ understanding of snake evolution was hampered by the limited fossil record. The new fossils presented in this study are crucial for reconstructing the early steps in the evolutionary history of modern snakes.

“This research revolutionizes our understanding of the jugal bone in snake and non-snake lizards,” said Michael Caldwell, professor in the Department of Biological Sciences and Earth and Atmospheric Sciences, and a co-author on the study. “After 160 years of getting it wrong, this paper corrects this very important feature based not on guesswork, but on empirical evidence.”

The nearly 100 million-year-old fossil snakes described in this study, found in Northern Patagonia, are closely related to an ancient lineage of snakes that populated the southern hemisphere continents of Gondwana, and appear to be related to only a small number of obscure, modern snakes. The researchers used micro-computed tomography (micro-CT) scanning to visualize the skull structures within the specimen, examining the pathways of nerves and blood vessels as well as the skeletal structure that would be otherwise impossible to see without damaging the fossil.

“This research is critical to understanding the evolution of the skulls of modern and ancient snakes,” added Caldwell.

Repenomamus, dinosaur-eating mammals


This 14 November 2019 video says about itself:

Repenomamus the Mammal that Ate Dinosaurs

This video shows that towards the end of the time of the dinosaurs, mammals were already starting to increase in size and occupy more carnivorous niches. Most notably among these was Repenomamus that has been found with a small dinosaur in its stomach.

Feathered polar dinosaurs discovery in Australia


This 2017 video says about itself:

Over the past 20 years, dinosaurs of all types and sizes have been found with some sort of fluff or even full-on plumage. These fuzzy discoveries have raised a whole batch of new questions so we’re here to tell you everything we know about dinosaurs and feathers.

From Uppsala University in Sweden:

First evidence of feathered polar dinosaurs found in Australia

November 12, 2019

A cache of 118 million-year-old fossilized dinosaur and bird feathers has been recovered from an ancient lake deposit that once lay beyond the southern polar circle.

Feathered dinosaur fossils are famous, but known from a handful of localities worldwide. Examples from the Southern Hemisphere are especially rare, and mainly include only isolated feathers.

An international team of scientists has analyzed a collection of 10 such fossil feathers found in Australia, which reveal an unexpected diversity of tufted hair-like ‘proto-feathers’ from meat-eating dinosaurs, together with downy body feathers, and wing feathers from primitive birds that would have been used for flight.

Uniquely, the fossil feathers from Australia were all entombed in fine muddy sediments that accumulated at the bottom of a shallow lake close to the South Pole during the Age of Dinosaurs.

“Dinosaur skeletons and even the fragile bones of early birds have been found at ancient high-latitudes before. Yet, to date, no directly attributable integumentary remains have been discovered to show that dinosaurs used feathers to survive in extreme polar habitats,” said Dr Benjamin Kear from Uppsala University in Sweden, a leading author on the study.

“These Australian fossil feathers are therefore highly significant because they came from dinosaurs and small birds that were living in a seasonally very cold environment with months of polar darkness every year.”

The fossil feathers were discovered in the Koonwarra Fish Beds Geological Reserve, which is a heritage-listed site 145 km southeast of Melbourne in Victoria, Australia.

“Fossil feathers have been known from Koonwarra since the early 1960s, and were recognized as evidence of ancient birds, but have otherwise received very little scientific attention. Our study is thus the first to comprehensively document these remains, which include new specimens that were examined using cutting-edge technologies,” said Dr Thomas Rich of the Melbourne Museum in Australia, who has led numerous expeditions to the Koonwarra locality.

A suite of advanced microscopic and spectroscopic techniques was employed to determine the anatomy and preservation of the Koonwarra fossil dinosaur and bird feathers.

“The Koonwarra feathers are preserved in incredible detail,” said fossil bird expert Professor Patricia Vickers-Rich of Monash University and the Swinburne University of Technology in Melbourne.

“There are even tiny filament-like structures that would have ‘zipped’ the feather vanes together, just as in the flight feathers of modern birds.”

However, unlike the structurally complex feathers of birds today, which are characterized by interlocking branches called barbs and barbules, different kinds of small dinosaurs had coverings that comprised much more simpler hair-like ‘proto-feathers’.

“Dinosaur ‘proto-feathers’ would have been used for insulation,” said Dr Martin Kundrát, of Pavol Jozef Safarik University in Slovakia, a leading author on the study.

“The discovery of ‘proto-feathers’ at Koonwarra therefore suggests that fluffy feather coats might have helped small dinosaurs keep warm in ancient polar habitats.”

Microscopic remains of possible melanosomes, cellular structures that contain colour pigments, were also detected on several of the fossil feathers found at Koonwarra.

These traces occurred across the uniformly dark feather surfaces, as well as in distinct bands that might represent original patterning from the polar dinosaurs and birds.

Melanic residues have been reported on fossil feathers from elsewhere around the world, and are widely acknowledged as indicators of dinosaur colouration.

The densely packed fossil melanosomes occurring on the Koonwarra feathers could suggest dark colours that perhaps assisted in camouflage, visual communication, and/or heat absorbance in cold polar climates.

Possible preservation of biomolecules was also assessed, but proved to be too degraded, and were apparently lost during weathering of the rock.

The Koonwarra fossil feathers provide the first record of dinosaur integument from the ancient polar regions, and hint what was once a global distribution of feathered dinosaurs and early birds.

Some of the fossil feathers found at Koonwarra are on display in the ‘600 Million Years’ exhibition at the Melbourne Museum in Australia.