Thursday, December 09, 2021

Fast-running theropods tracks from the Early Cretaceous of La Rioja, Spain

Article
Open Access
Published: 09 December 2021

Pablo Navarro-Lorbés,

Javier Ruiz,

Ignacio Díaz-Martínez,

Erik Isasmendi,

Patxi Sáez-Benito,

Luis Viera,

Xabier Pereda-Suberbiola &

Angélica Torices

Scientific Reports volume 11, Article number: 23095 (2021) Cite this article

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Abstract

Theropod behaviour and biodynamics are intriguing questions that paleontology has been trying to resolve for a long time. The lack of extant groups with similar bipedalism has made it hard to answer some of the questions on the matter, yet theoretical biomechanical models have shed some light on the question of how fast theropods could run and what kind of movement they showed. The study of dinosaur tracks can help answer some of these questions due to the very nature of tracks as a product of the interaction of these animals with the environment. Two trackways belonging to fast-running theropods from the Lower Cretaceous Enciso Group of Igea (La Rioja) are presented here and compared with other fast-running theropod trackways published to date. The Lower Cretaceous Iberian fossil record and some features present in these footprints and trackways suggest a basal tetanuran, probably a carcharodontosaurid or spinosaurid, as a plausible trackmaker. Speed analysis shows that these trackways, with speed ranges of 6.5–10.3 and 8.8–12.4 ms−1, testify to some of the top speeds ever calculated for theropod tracks, shedding light on the question of dinosaur biodynamics and how these animals moved.

Introduction

One of the perennial questions in the paleobiology of non-avian theropod dinosaurs is their capacity for locomotion, e.g.1,2. How did they move? How fast did they go? Over the years, these questions have been approached from various points of view based on osteological information, with anatomical (e.g., morphology, muscular attachments, size) and anatomically-derived biomechanical models (e.g., mass, force, and momentum) being used to estimate the maximum speed of locomotion3,4,5,6,7. Another way of better understanding how extinct theropods moved is to examine their tracks and trackways, e.g.8. To this end, Alexander9 proposed an equation using dynamic similarity to calculate the absolute speed of dinosaurs from ichnological data on the basis of footprint length (to obtain the height at the hip) and stride length. This and other methods e.g.10,11 have been used in the last few decades by many ichnologists to analyse the locomotion dynamics shown by hundreds of trackways, e.g.11,12,13,14.

Walking is the most common behaviour inferred from dinosaur fossil trackways9,10,11,15, although some minor cases of running or trotting have also been identified13,16,17,18,19,20,21,22,23. Indeed, 96% of the 1802 Kayentapus dinosaur strides studied by Weems 13 were made by animals with a walking behaviour, whereas just 4% of them were made by dinosaurs with a more energetic way of movement. Of this 4%, the great majority is consistent with trotting displacement, whereas just one of the trackways could correspond to a running behaviour13. In the Early Cretaceous of Spain, a theropod trackway of six consecutive footprints with pace lengths of more than two metres preserved in a trampled surface was found at La Torre 6B (Igea, La Rioja)24 (Fig. 1), for which has been inferred high speeds of more than 10 ms−1 (Refs.25,26,27). The trackway from La Torre 6A was initially mentioned by Aguirrezabala et al.24 with the presence of two non-consecutive footprints and the probable presence of a third between them, lost by erosion. During new field campaigns in this area, two significant findings have recently been made: a new footprint was discovered to add to the La Torre 6B trackway, and the discovery of three new footprints in La Torre 6A that confirm the presence of a second high-speed trackway in La Torre tracksites. Both trackways shed light on locomotion, speeds and even behaviour of non-avian theropods.

Results and discussion

Tracks and trackways

The La Torre 6A-14 trackway (Fig. 2) preserves only five of the six footprints because the third footprint in the trackway was at a point of the tracksite where the top layers of rock have been lost. The footprints are tridactyl, functionally mesaxonic, and longer than wide (mean length and width, respectively, of 32.8 cm and 30.2 cm). The footprints show well-preserved digit impressions (Fig. 3A). The divarication angle between the digit II and IV impressions is about 67° and varies from 57° to 75°. The metatarsophalangeal area is very shallow in the first footprint and elongated in footprints 2, 4 and 6. The impression of digit II is always deeper than digit IV, and in footprints 2 and 4 a sharp longitudinal groove is preserved, probably related to the claw imprint. The digit III impression also shows a deep area in its distal zone, but the claw imprint is at a higher level than the rest of the digit. In footprint 6, the posterior area of digit III is preserved as a narrow and shallow groove. Pad imprints are identified in footprints 2, 4, and 5. The impression of digit IV is elongated, has a sharp distal end, and is the shallowest of all digits. The mean values for the pace angulation, stride length and pace length are 169°, 523 cm and 265 cm, respectively.

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Fast-running theropods tracks from the Early Cretaceous of La Rioja, Spain | Scientific Reports (nature.com)

How Did Crocodiles Survive the Asteroid That Wiped Out the Dinosaurs?

By MIKE LEE, FLINDERS UNIVERSITY DECEMBER 8, 2021

Asteroid Planet Atmosphere

There are two main reasons crocodiles survived the asteroid that killed the dinosaurs. First, crocodiles can live for a very long time without food. Second, they lived in places that were the least affected when the asteroid hit Earth.

When the asteroid hit earth

About 66 million years ago, dinosaurs ruled Earth. But then a massive asteroid, more than 9 kilometers wide, slammed into the shallow sea near what is now Mexico.

The explosion from this was so huge, it led to global earthquakes, tidal waves, bushfires, and even poisonous rain.

Also, the asteroid hit at one of the worst possible places, where the rocks could easily be “exploded” (or vapourised). This threw up massive amounts of dust into the sky, blocking out the Sun for many months and sending Earth into a long, dark, and freezing winter.

Without sunlight, the green plants died, followed by the plant-eating animals that ate them to survive, and the meat-eaters that ate the plant-eaters.

Credit: Michael Lee

Scientists think three-quarters of all the different kinds (species) of animals on Earth were wiped out – including most dinosaurs.

But some managed to survive for a range of reasons.

One important group of dinosaurs sailed through, helped by their ability to fly and find food in faraway places. Their feathers protected them from the cold, and their beaks let them eat buried seeds found near dead plants.

Amazingly, these dinosaur survivors are still with us today. We call them birds!

A battle-scarred saltwater crocodile resting near the Daintree River in North Queensland. Credit: Michael Lee

Crocodiles had some keys to survival

Crocodiles were another group that famously survived the asteroid. Obviously, they can’t fly, don’t have feathers, and don’t eat seeds! But they had other secrets to success.

Firstly, crocodile bodies use very little energy. They lie around a lot, breathe slowly and even have a very slow heartbeat. This is how they can hold their breath underwater for more than an hour.

It also means they can go without food for months, and sometimes more than a year. This would have been very helpful when food (such as other animals) became hard to find once the asteroid hit.

Dinosaurs, on the other hand, were generally more active, which means they needed more energy – especially meat-eaters like Velociraptor. Without food, they would have died quickly.

Dinosaurs such as Velociraptor would have struggled to survive without much food after the asteroid hit. That is, if they survived in the first place.

Crocodiles also lived in places where losing green plants didn’t make a big difference. Think of a forest or a grassland (where many dinosaurs lived): if the plants there die, then all the animals that need them die too, including the meat-eaters which are left with no food.

But the crocodile survivors mostly lived in places like rivers, lakes, and coasts. The animals living in these places don’t need green plants as much. Dead plants and animal material washes in from surrounding land, which is eaten by tiny creatures, which are then eaten by larger creatures including crocodiles.

So unlike dinosaurs living on the land, crocodiles in a river would not have starved as soon as the green plants died.

Our mammalian ancestors also survived

A similar reason helps explain why human beings’ ancestors also survived the asteroid impact. These were the small mammals that lived near the end of the age of dinosaurs, which eventually gave rise to all the different kinds of mammals around today (including humans).

They were mainly small, rat-like things that scurried about in the dead leaf litter on the ground, eating insects and worms. These tiny creatures relied not on living green plants, but on dead leaves and bark falling from the trees, or being blown and washed in from elsewhere.

So just like the crocodiles, our tiny ancestors survived the asteroid partly because they didn’t depend heavily on living plants. A good thing too: these lucky survival skills are the reason you and I are here today!

Written by Mike Lee, Professor in Evolutionary Biology (jointly appointed with South Australian Museum), Flinders University.

This article was first published in The Conversation.

This faraway galaxy may be completely devoid of dark matter

By Mara Johnson-Groh

published 1 day ago

A galaxy without dark matter would upend fundamental theories about galaxy formation.

The galaxy AGC 114905 seems to be devoid of dark matter. In this image, the stellar emission is shown in blue; and green clouds show the neutral hydrogen gas. (Image credit: Javier Román & Pavel Mancera Piña, CC BY 4.0)

On the surface, a galaxy 250 million light-years from Earth seems like any other, but a deeper look reveals a puzzling quirk: It seems to have no dark matter.

If these galaxies are ultimately confirmed to be devoid of dark matter, it could upend fundamental theories about the making of galaxies (dark matter is considered essential to this process). And that, in turn, could rule out a leading candidate for the mysterious substance, called cold dark matter.

"In principle, galaxies like this shouldn't exist," said Pavel Mancera Piña, a doctoral candidate in astronomy at the University of Groningen in the Netherlands and an astronomer at ASTRON (the Netherlands Institute for Radio Astronomy), referring to the fact that dark matter is thought to be the glue that holds a galaxy's stars, gas and dust together. "We cannot effectively explain them with any existing theory," said Mancera Piña, who is the lead author of a new paper describing the findings.

The galaxy, called AGC 114905, is an ultradiffuse galaxy (UDG). These galaxies are faint; AGC 114905 is about the same size as the Milky Way but has 1,000 times fewer stars.

When Mancera Piña and his colleagues first looked at AGC 114905 in 2019 , they suspected it might not have dark matter because of how fast it was rotating. The speed at which a galaxy rotates reveals how much stuff it contains; the more massive a galaxy, the stronger its gravity and the faster it spins. By comparing the speed with how much stuff can be seen — the amount of stars, gas and dust — astronomers can work backward to figure out how much extra invisible stuff — dark matter — must be present to account for the speed of the galaxy.

But because the galaxy in question is so faint, they didn't have enough data initially to fully resolve the rotation speed to tell if it was totally devoid of dark matter. So they went back for a second look, compiling 40 hours of observations with the Very Large Array, a radio observatory in New Mexico.

Through their observations, which mapped the gas in the galaxy, the astronomers figured out how fast the gas was moving. This allowed them to figure out the galaxy's rotation speed and thus how much dark matter is present in the galaxy. But ultimately the researchers concluded that there doesn't seem to be any room for dark matter.

"That's what we were expecting, of course, but you never know," Mancera Piña said. "It was still a bit of a surprise."

Missing dark matter

In the past, astronomers have discovered some UDGs that are rich in dark matter and others lacking it, Live Science previously reported. Some of the latter type are found near more massive galaxies; this finding suggests they may have lost their dark matter through interactions with their larger nearby galaxies, whose gravity may have whisked the smaller galaxies' dark matter away. But considering AGC 114905 doesn't have any massive galaxies nearby, that explanation is unlikely, Mancera Piña said.

This poses a challenge to theories of galaxy formation, because dark matter is thought to be essential for their formation, as its gravity helps pull the relatively rarer normal material together. If there are galaxies with no dark matter, that implies dark matter may not be needed to form galaxies.

Studying AGC 114905 also gives astronomers a new way to test the nature of dark matter. Current theories of galaxy formation rely on a special type of dark matter called cold dark matter, but if those theories don't explain weird galaxies like AGC 114905, then maybe cold dark matter isn't workable either.

"We have been trying to understand what dark matter is for the last 50 years, but we seem to have reached some kind of dead end," Mancera Piña said. By carefully studying this galaxy and others like it, the astronomers might be able to provide constraints on what dark matter might be like, if it's not cold dark matter. In the study, the researchers also applied models of an alternative theory to dark matter called Modified Newtonian dynamics, or MOND, to see if that could explain the galaxy's unique characteristics. However, this theory wasn't able to reconcile the speed of the galaxy either.

Pieter van Dokkum, an astronomer atYale University who has studied dark matter-deficient UDGs but was not involved with the new work, said he thinks the new findings are promising and significant, but that more research will be required for astronomers to be sure the galaxy is truly devoid of dark matter.

"There will be a lot of discussion," van Dokkum said. "Extraordinary claims require extraordinary evidence."

The study authors plan to study AGC 114905 further and are gathering observations of other UDGs that might be free of dark matter.

The findings were published on Nov. 30 to the preprint server arXiv and have been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.

Originally published on Live Science.

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LA REVUE GAUCHE - Left Comment: Search results for AETHYR

LA REVUE GAUCHE - Left Comment: Search results for ETHER

THIS PHOTO OF THE SUN IS SO ABSURDLY DETAILED THAT IT LOOKS LIKE A LIVING ORGANISM

"ORDINARILY, TAKING A TELESCOPE AND POINTING AT THE SUN WOULD BE INCREDIBLY DANGEROUS."

Black Hole Sun

Famed astrophotographer Andrew McCarthy has truly outdone himself with his latest picture of the Sun.

McCarthy, who calls himself “just a normal guy with a telescope” on his Instagram account, stitched a whopping 150,000 images of the Sun together to form a massive 300 megapixel image he titled “Fire and Fusion.”

The result is a glorious swirling mess of hot gases that almost appear almost organism-like — an angry ball of energy that gave life to everything around us billions of years ago.

What makes it all the more impressive was the fact that it was taken from a backyard, rather than by an orbital telescope or space probe that had to travel almost 100 million miles to get up close.

OPINION

As reigning world chess champion Magnus Carlsen marches toward a fifth straight title, the question is: Is he so good that it’s bad?

CATHAL KELLY

THE GLOBE AND MAIL

SPORT

If you like your sports narratives with some Biblical flavour, this year’s world chess championships is for you.

It’s no longer nearly good enough to call the defending (x4) champion Magnus Carlsen the favourite in any tournament. He is the highest rated player in history. He’s been world No. 1 for nearly a decade. He’s been world champion for that whole stretch.

This time around, the poor sap lined up against him against him is a Russian, Ian Nepomniachtchi, commonly referred to as Nepo.

Like a lot of top chess players, Nepo doesn’t exactly leap from your screen via his irresistible physical charisma. The only visually interesting thing about him is that he wears a top knot. You get the feeling this guy may be a little too into Kurosawa.

For the first bit, things were progressing alright for Nepo against the peerless Norwegian. After seven of the planned 14 games, they’d drawn a half-dozen times.

According to the computers that measure such things, a couple of those games ranked 1-2 as the most tactically precise encounters in world chess championship history. We were watching two masters at work.

Carlsen was still winning, but Nepo was in there with a shot. Then we got to the eighth game.

It was played after a rest day. Nepo showed up having shorn off the top knot. Apparently, he is the first ever professional athlete who thinks that when things are bumping along just fine, that’s the time to make a major change to your routine.

In chess, there are three categories of error - inaccuracies, mistakes and blunders.

Midway through the game, Nepo blundered. In notation, the move was 27 C5. He dangled a pawn and left a bishop exposed.

The mistake was so enormous that it left Carlsen shaking his head slowly in wonderment. Either he couldn’t believe his luck, or he resented an opponent beating himself before he had a chance to do so. Once he realized what he’d done (almost instantaneously), Nepo leapt from his chair and fled the playing hall.

“You work your whole lifetime for one shot and this is what happens on the biggest scene,” British chess champion David Howell said, according to the Guardian. “He’s probably never blundered like this in his whole career. It’s just so sad.”

Nepo lost the ninth game as well, and then drew the tenth. Needing four straight wins over a guy who’s never lost more than one at a world championships, he was asked if his “strategy” remained “trying to win this match.”

“That is an absurd question,” Nepo said.

I’ll give chess this much - it’s populated by realists. Carlsen’s triumphal march toward a fifth straight title resumes on Friday.

That will leave us with an unusual question about Carlsen at his most imperious - is he so good that it is bad?

He is still young (31). He presents well in public, and has never done anything to toxify his brand. He’s good looking enough to work as a model.

Yet despite all these ancillary advantages to go along with his growing best-ever credentials, it feels like Carlsen is doing a slow fade on the global stage. He is not talked about nearly as much as he once was. The last time he made headlines unconnected to a specific chess match was when he briefly held first place in a British fantasy football league.

Carlsen is so excellent and wins so reliably, that it has the curious effect of deflecting interest, both from him and from chess.

Because who wants to watch a guy cruise to victory every single time? The David v. Goliath narrative is the most reliable crowd-pleaser in sports, but it works the opposite way around if Goliath wins.

For a while, Carlsen was presented as David - because he was young and looked younger in a sport we associate with fossilized beardos. But the No. 2 ranked player in the world, Alireza Firouzja, is only 18 years old. Carlsen is a fossil v now.

‘Teenage genius comes out of nowhere to stun chess world’ - that’s sexy.

‘Guy you already heard about a bunch of times is still here’ - that’s not.

The last crossover chess star was Gary Kasparov (If we define ‘crossover’ as ‘playing chess with David Letterman on live TV over the phone’). Kasparov won his sixth and final world title when he was 32 years old.

By that point, he’d also worn out his welcome in the chess world. A series of administrative roadblocks were thrown up to make it more difficult for him to find his way back into the centre. Kasparov retired in frustration ten years later.

Someone somewhere must have understood that people don’t want great. They want great, but with complications. They want it to burst onto the scene and dominate for a little bit and then disappear. Or they want it to toil for years and then finally get over the hump. Or they want a rise and a fall and a rise again.

What they don’t want is uninterrupted dominance. It offends the audience’s mediocrity. It prompts envy. Most dangerously, it bores people.

This is why people love Roger Federer so much. He was the greatest of all time, and then around the time that would have started to get annoying, he wasn’t. By his own standard, he became embarrassingly bad. Then he got good again. Now he’s back to being bad.

That’s an arc that sings. It’s exaggeratedly human, but not super-human. The rubes love that.

Maybe that’s Carlsen had such a dark look when Nepo hung that bishop out in no man’s land in Game 8. He knew in that instant that he was going to win again, as well as knowing that it wasn’t going to be the right sort of win.

RIP

Life and Times: Tom Doran was much more than Edmonton's Godfather of Drums

Author of the article:Roger Levesque
Publishing date:Dec 09, 2021 •

Tom Doran, Edmonton's Godfather of drums, died Nov.30, 2021.

PHOTO BY SUPPLIED
Article content

Edmonton’s musical community skipped a few beats following the recent death of groove master Tom Doran at the age of 78.

The Edmonton-born drummer, who enjoyed a side career as an entrepreneur, was best known as the man who kept time for late bandleader Tommy Banks through several decades but that only begins to sum up his multifaceted career.

As a first-call drummer to Banks and others, Doran tackled jazz, rock ‘n’ roll, R&B, country and other genres with grace, palpable enthusiasm and superior technique, going on to influence, encourage and occasionally teach younger generations of musicians. Lending his talents to several collectives, he also backed up the likes of David Foster, Paul Horn, Big Miller, George Blondheim, Lenny Breau, Cheryl Fisher, Kennedy Jensen and many more.

Doran was one of the last surviving members of Banks’ early variety band, The Banknotes, and the original Tommy Banks Big Band. The Big Band’s recorded appearance at the 1978 Montreux Jazz Festival won a Juno Award the following year.

Backing rock-pop units like The Original Caste, he joined Privilege for an extended U.S. tour performing Jesus Christ Superstar. Doran shared musical direction in projects like Wizard (later Blizzard) with other Edmonton music greats like Earl Seymour, The Jury with Mo Marshall and the Vancouver-based Django with Gaye Delorme and Hans Stammer.

During the 1970s and early 1980s when Banks’ groups figured in the hit television series Celebrity Review (later The Tommy Banks Show) and the ITV In Concert series with the Edmonton Symphony Orchestra, Doran’s drumming helped anchor appearances with international celebrities like Aretha Franklin, Tom Jones and Tina Turner. Banks nicknamed him “Drum” and many considered him Edmonton’s Godfather of drums.

Doran’s business ventures reflected his spiritual and artistic interests. Based in and around Old Strathcona for the better part of 40 years, he and his wife Denyse founded the metaphysical Ananda Books in the mid-’70s, Jupiter Crystal in 1982, and Remedy Cafe (now under different owners) later that decade.

Jupiter gradually morphed into Jupiter Glass, a successful outlet for Doran’s handcrafted glass art, jewellery creations and later, glass pipes. Since closing the Whyte Avenue store in September this year, their kids Sara and Tom Doran Jr. continue to market through the Winnipeg-based online venture Jupiter Cannabis.

Everyone who knew him insists Doran had an especially friendly, gentle personality. His wife Denyse credits that agreeable demeanour to “the profound influence” of his daily five-decade practice of meditation.

In an interview for the Journal in 1999, Doran said he felt his real talent grew from “hands-on trial and error”. His first drum was actually the pot of an old banjo he played with tree twigs. Seeing Louis Armstrong at age 10 steered him in the right direction and the three Doran brothers made an amateur trio. He started lessons at Heinzmen’s Music at age 12, with private lessons from Art Darch, but working with Bernie Senensky and Winston Mays taught him the fundamentals of jazz.

After starting out in a teenage rock band with pal Mo Marshall, his first official gig came in 1957 with accordion-polka king Gaby Haas. The original Yardbird Suite jazz club had recently opened and within a year Doran was a regular patron, listening to the likes of Banks, Phil Shragge and Terry Hawkeye. Finally, one Saturday night he got to jam and, as he was earlier quoted, “I was hooked on jazz after that.”

Early stints in local bands like James and the Bondsman, and with Hank DeMarco led to work at The Jazz Door with Lenny Breau and P.J. Perry. Banks asked Doran to join his quartet in 1967 and the band played Expo ’67 in Montreal.

A late ’60s sojourn to Vancouver found Doran drumming in an experimental jazz fusion sextet Django, which played a club owned by the family of Tommy Chong, who became one of his best friends.

Django member and former Edmonton guitarist-singer Hans Stammer recalls Doran, saying, “I was always amazed by what a beautiful sound he had and his style of playing. He was a fantastic drummer, so easy to play with, adjusting when the band stretched out whatever the music involved. He always sounded great and he was such a nice person to be with.”

Long before the internet, Edmonton’s live music scene offered an abundance of venues. Doran put in regular work with Banks at clubs like The Embers and accompanied by vocalists like Judy Singh, and guests like David Foster, or with Bob Stroup at the Palms Cafe. Banks’ later television projects kept Doran busy with session work at multiple television studios here and in Vancouver.

On the beat

Doran was a consummate professional whose versatility put him in high demand and he appeared on dozens of recordings.

It was Paul Horn who turned Doran on to the benefits of meditation in the early 1970s and it’s no surprise the late American-born flautist hired him for extended tours of the U.S. and Canada in 1972. Horn had a thing for hiring great jazz drummers but at the time his career was shifting from jazz to pioneering meditative sounds in new age and world music. Doran fit that musical equation perfectly.

The drummer made room to work with countless younger players and briefly taught drums in the original MacEwan College jazz program. When Banks agreed to produce the debut recording of singer and radio (CKUA, CJSR, NPR) broadcaster Dianne Donovan in 1997, Doran signed on to fashion the grooves.

“I had heard so much about him,” Donovan recalls. “I was a little nervous or shy around him. However, he was the uber-pro, exacting, tasty and never overblown. It was an honour to have him on the album.”

Tom and Denyse Doran were both early advocates for the legalization of cannabis. He wasn’t one to shy away from saying so and aware enough to know the benefits of using everything in moderation. His wife observed that, “Tom had a tremendous interest in cannabis. He was really stoned a lot in the 1960s but he straightened himself out.”

She considered her husband to be, “an uncanny magnet for good fortune.”

Doran restored old automobiles as a hobby and his mechanical talents also put him in demand with Banks. As Denyse tells it, “When they went on road trips Tom Banks always made Tom (Doran) ride with him, because (Doran) was mechanical, and if something went wrong with the car, Banks knew that Tom could fix it.”

It’s difficult to sum up Doran’s life and work. His contribution to the city’s music scene will live like a subtle, stylish whisper of brushes on the snares, for years to come.

I interviewed Doran in 1999 when he announced one of several retirements from Banks’ band (it speaks volumes that Banks kept pushing him to come back). At the time, Doran pondered what a good musical situation was, saying, “Any band where the music (is) played with sincerity and a true sense of exploration in finding and going to new musical places. That’s my favourite thing, a musical adventure.”

Doran died Nov. 30 following a long struggle with renal failure. He’s survived by his wife of 50 years, Denyse, their children Leila, Thomas Jr. and Sara, and his brother Brian.

yegarts@postmedia.com