Ancient sea scorpions, new research


This video says about itself:

13 September 2016

Today we examine the amazingly bizarre group of prehistoric arthropods, the Eurypterids or sea scorpions of the Paleozoic. We answer questions like: Where they really scorpions? How large did they get? And what are they exactly?

From the University of Alberta in Canada:

Sea scorpions: The original sea monster

Sea scorpions used serrated tail spine to dispatch their prey, researchers suggest

April 18, 2017

Summary: Related to both modern scorpions and horseshow [sic: horseshoe] crabs, sea scorpions had thin, flexible bodies. Some species also had pinching claws and could grow up to three metres in length. New research that the sea scorpions had another weapon at their disposal: a serrated, slashing tail spine.

Four hundred and thirty million years ago, long before the evolution of barracudas or sharks, a different kind of predator stalked the primordial seas. The original sea monsters were eurypterids — better known as sea scorpions.

Related to both modern scorpions and horseshow [sic: horseshoe] crabs, sea scorpions had thin, flexible bodies. Some species also had pinching claws and could grow up to three metres in length. New research by University of Alberta scientists Scott Persons and John Acorn hypothesise that the sea scorpions had another weapon at their disposal: a serrated, slashing tail spine.

Armed and dangerous

“Our study suggests that sea scorpions used their tails, weaponized by their serrated spiny tips, to dispatch their prey,” says Scott Persons, paleontologist and lead author on the study.

Sparked by the discovery of a new fossil specimen of the eurypterid Slimonia acuminata, Persons and Acorn make the biomechanical case that these sea scorpions attacked and killed their prey with sidelong strikes of their serrated tail.

The fossil, collected from the Patrick Burn Formation near Lesmahagow, Scotland, shows a eurypterid Slimonia acuminata, with a serrated-spine-tipped tail curved strongly to one side.

Powerful weapons

Unlike lobsters and shrimps, which can flip their broad tails up and down to help them swim, eurypterid tails were vertically inflexible but horizontally highly mobile.

“This means that these sea scorpions could slash their tails from side to side, meeting little hydraulic resistance and without propelling themselves away from an intended target,” explains Persons. “Perhaps clutching their prey with their sharp front limbs eurypterids could kill pretty [well] using a horizontal slashing motion.”

Among the likely prey of Slimonia acuminata and other eurypterids were ancient early vertebrates.

Megatherium giant sloth was vegetarian


This February 2017 video is called 10 Interesting Facts About Sloths.

From the Senckenberg Research Institute and Natural History Museum in Germany:

Giant sloth was vegetarian: Diet of fossil Megatherium decoded

April 18, 2017

Summary: Scientists have examined the diet of the extinct Giant Sloth Megatherium. Based on analyses of the collagen in the fossil bones, the researchers concluded in their study that Megatherium subsisted on an exclusively vegetarian diet. Until recently, there had been much speculation about the food habits of these elephant-sized, ground-dwelling animals.

Together with an international team, Senckenberg scientists examined the diet of the extinct Giant Sloth Megatherium. Based on analyses of the collagen in the fossil bones, the researchers concluded in their study, which was recently published in the scientific journal Gondwana Research that Megatherium subsisted on an exclusively vegetarian diet. Until recently, there had been much speculation about the food habits of these elephant-sized, ground-dwelling animals.

Sloths may well rank among the world’s most peculiar animals: With their backs pointing downward, they hang in trees and move in slow motion from branch to branch with the aid of their sickle-shaped claws. “Sloths already occurred 10,000 years ago, for example the species Megatherium,” explains Professor Dr. Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment at the University of Tübingen.

The extinct relatives of the sloths could reach the size of an elephant and were much too heavy to spend a significant amount of time in the trees. Instead, they lived on the ground, where they excavated large burrows. For many years, their dietary habits were an enigma; the long claws on their hands and feet, in particular, gave rise to various speculations. Did the sloths use their claws to dig up subterranean insect colonies? Did the long claws serve as hunting tools, and were the giant animals carnivores? Or did the fossil representatives live on a strictly vegetarian diet, like the recent sloths? “These questions were at the center of our new study,” adds Bocherens.

Normally it is possible to deduce the feeding habits of fossil animals on the basis of the shape and wear of their teeth – however, the teeth of the Giant Sloth are not comparable to those of modern animals. “We therefore had to use a different method, so we measured the composition of carbon isotopes – the ratio of protein and mineral content – in the fossilized sloth bones,” explains Bocherens, and he continues, “Our measurements show that Megatherium lived on an exclusively vegetarian diet.”

In carnivores, the proportion of proteins is significantly higher than in herbivores, which primarily eat food high in carbohydrates. These differences can be documented in the isotopes. In order to reinforce their results, the scientists compared their data with more than 200 bones from modern mammals, whose diet is known, as well as with fossil specimens from both carnivores and herbivores. “Our results show that by using this method, it is possible to reconstruct the feeding habits of animals even several thousand years after their death,” adds the biogeologist from Tübingen.

Knowledge of the sloths’ feeding habits is important in order to understand their role in past ecosystems. “Moreover, the results can help us understand the interactions between Megatherium and the first human inhabitants of America – their habitats overlapped for several thousand years, before the Giant Sloth became extinct,” offers Bocherens as a preview.

Nectar helps hawk moths’ health


This video from the USA says about itself:

17 April 2014

Gain an understanding of the tobacco hornworm (Manduca sexta) life cycle by observing the growth and development of hornworm larvae in a vial. Learn about the integral steps of care and handling throughout this life cycle to witness the emergence of an adult moth.

From Science News:

Hawk moths convert nectar into antioxidants

Energetic fliers found a way to reduce muscle damage

By Elizabeth Eaton

7:00am, April 17, 2017

Hawk moths have a sweet solution to muscle damage.

Manduca sexta moths dine solely on nectar, but the sugary liquid does more than fuel their bodies. The insects convert some of the sugars into antioxidants that protect the moths’ hardworking muscles, researchers report in the Feb. 17 Science.

When animals expend a lot of energy, like hawk moths do as they rapidly beat their wings to hover at a flower, their bodies produce reactive molecules, which attack muscle and other cells. Humans and other animals eat foods that contain antioxidants that neutralize the harmful molecules. But the moths’ singular food source — nectar — has little to no antioxidants.

So the insects make their own. They send some of the nectar sugars through an alternative metabolic pathway to make antioxidants instead of energy, says study coauthor Eran Levin, an entomologist now at Tel Aviv University. Levin and colleagues say this mechanism may have allowed nectar-loving animals to evolve into powerful, energy-intensive fliers.

Moabosaurus dinosaur discovery in Utah, USA


This video from the USA says about itself:

12 April 2017

BYU [Brigham Young University] professors have discovered a new species of dinosaur Moabosaurus utahensis, named to honor Moab, Utah, which paleontologists consider Utah’s ‘gold mine’.

The bones of the dinosaur were unearthed near Moab, Utah.

The 32-foot herbivore is a relative of the long-necked Brontosaurus and Brachiosaurus.

An assembled skeleton is on display at BYU’s Museum of Paleontology in Provo, Utah.

From Brigham Young University in the USA:

Moabosaurus discovered in Utah‘s ‘gold mine’

April 13, 2017

Summary: Move over, honeybee and seagull: it’s time to meet Moabosaurus utahensis, Utah’s newly discovered dinosaur, whose past reveals even more about the state’s long-term history. The bones of the 125-million-year-old dinosaur were extracted over the course of four decades from a quarry near Arches National Park.

Move over, honeybee and seagull: it’s time to meet Moabosaurus utahensis, Utah’s newly discovered dinosaur, whose past reveals even more about the state’s long-term history.

The Moabosaurus discovery was published this week by the University of Michigan’s Contributions from the Museum of Paleontology. The paper, authored by three Brigham Young University researchers and a BYU graduate at Auburn University, profiles Moabosaurus, a 125-million-year-old dinosaur whose skeleton was assembled using bones extracted from the Dalton Wells Quarry, near Arches National Park.

BYU geology professor and lead author Brooks Britt explained that in analyzing dinosaur bones, he and colleagues rely on constant comparisons with other related specimens. If there are enough distinguishing features to make it unique, it’s new.

“It’s like looking at a piece of a car,” Britt said. “You can look at it and say it belongs to a Ford sedan, but it’s not exactly a Focus or a Fusion or a Fiesta. We do the same with dinosaurs.”

Moabosaurus belongs to a group of herbivorous dinosaurs known as sauropods, which includes giants such as Brontosaurus and Brachiosaurus, who had long necks and pillar-like legs. Moabosaurus is most closely related to species found in Spain and Tanzania, which tells researchers that during its time, there were still intermittent physical connections between Europe, Africa and North America.

Moabosaurus lived in Utah before it resembled the desert we know — when it was filled with large trees, plentiful streams, lakes and dinosaurs. “We always think of Moab in terms of tourism and outdoor activities, but a paleontologist thinks of Moab as a gold mine for dinosaur bones,” Britt said.

In naming the species, Britt and his team, which included BYU Museum of Paleontology curator Rod Scheetz and biology professor Michael Whiting, decided to pay tribute to that gold mine. “We’re honoring the city of Moab and the State of Utah because they were so supportive of our excavation efforts over the decades it’s taken us to pull the animal out of the ground,” Britt said, referencing the digs that began when he was a BYU geology student in the late ’70s.

A previous study indicates that a large number of Moabosaurus and other dinosaurs died in a severe drought. Survivors trampled their fallen companions’ bodies, crushing their bones. After the drought ended, streams eroded the land, and transported the bones a short distance, where they were again trampled. Meanwhile, insects in the soils fed on the bones, leaving behind tell-tale burrow marks.

“We’re lucky to get anything out of this site,” Britt said. “Most bones we find are fragmentary, so only a small percentage of them are usable. And that’s why it took so long to get this animal put together: we had to collect huge numbers of bones in order to get enough that were complete.”

BYU has a legacy of collecting dinosaurs that started in the early 1960s, and Britt and colleagues are continuing their excavation efforts in eastern Utah. Moabosaurus now joins a range of other findings currently on display at BYU’s Museum of Paleontology — though, until its placard is updated, it’s identified as “Not yet named” (pronunciation: NOT-yet-NAIM-ed).

“Sure, we could find bones at other places in the world, but we find so many right here in Utah,” Britt said. “You don’t have to travel the world to discover new animals.”

How young eels swim, new research


This video from Pennsylvania in the USA says about itself:

Stocking Susquehanna tributaries with baby eels to improve water quality, Buchart Horn, York PA

27 June 2011

As part of the Sunbury, PA Riverfront Improvement Project, Buchart Horn proposed baby eels be re-introduced into the Susquehanna River watershed. Freshwater mussels filter and improve water quality. Freshwater mussel larvae piggyback on ells. Eels extend mussel habitat. More eels equals more mussels. More mussels equals cleaner water.

From Science News:

Young eels use magnetic ‘sixth sense’ to navigate

Ability explains how fish find ocean currents that sweep them to Europe’s rivers

By Laurel Hamers

12:06pm, April 13, 2017

Earth’s magnetic field helps eels go with the flow.

The Gulf Stream fast-tracks young European eels from their birthplace in the Sargasso Sea to the European rivers where they grow up. Eels can sense changes in Earth’s magnetic field to find those highways in a featureless expanse of ocean — even if it means swimming away from their ultimate destination at first, researchers report in the April 13 Current Biology.

European eels (Anguilla anguilla) mate and lay eggs in the salty waters of the Sargasso Sea, a seaweed-rich region in the North Atlantic Ocean. But the fish spend most of their adult lives living in freshwater rivers and estuaries in Europe and North Africa.

Exactly how eels make their journey from seawater to freshwater has baffled scientists for more than a century, says Nathan Putman, a biologist with the National Oceanic and Atmospheric Administration in Miami.

The critters are hard to track. “They’re elusive,” says study coauthor Lewis Naisbett-Jones, a biologist now at the University of North Carolina at Chapel Hill. “They migrate at night and at depth. The only reason we know they spawn in the Sargasso Sea is because that’s where the smallest larvae have been collected.”

Some other marine animals, like sea turtles and salmon, tune in to subtle changes in Earth’s magnetic field to help them migrate long distances. To test whether eels might have the same ability, Putman and his colleagues placed young European eels in a 3,000-liter tank of saltwater surrounded by copper wires. Running electric current through the wires simulated the magnetic field experienced at different places on Earth.

With no electric current, the eels didn’t swim in any particular direction. But when the magnetic field matched what eels would experience in the Sargasso Sea, the fish mostly swam to the southwest corner of their tank. That suggests the eels might use the magnetic field as a guide to help them move in a specific direction to leave their spawning grounds.

Swimming southwest from the Sargasso Sea seems counterintuitive for an eel trying to ultimately go northeast, Putman says. But computer simulations revealed that that particular bearing would push eels into the Gulf Stream, whisking them off to Europe. Catching a more circuitous ride on a current is probably more efficient for the eels than swimming directly across the North Atlantic, says Putman.

Magnetic fields could help eels stay the course, too. A magnetic field corresponding to a spot in the North Atlantic further along the eels’ route to Europe sent the eels in the tank heading northeast. That’s the direction they’d need to go to keep following the Gulf Stream to Europe.

The researchers did see a fair amount of variation in how strongly individual eels responded to magnetic fields. But that makes sense, says Julian Dodson, a biologist at Laval University in Quebec City who wasn’t part of the study. The Gulf Stream is such a powerful current that the eels could wriggle in a spread of directions to get swept up in its flow.

Now, the researchers are looking at whether adult eels use a similar magnetic map to get back to the Sargasso Sea. Adults follow a meandering return route that might take more than a year to complete, previous research suggests (SN Online: 10/5/16). But whether there’s some underlying force that guides them remains to be seen.

Injured African ants brought back to nest to recover


This video says about itself:

No Ant Left Behind: Warrior Ants Carry Injured Comrades Home

12 April 2017

Leave no man behind. That’s an old idea in warfare — it’s even part of the Soldier’s Creed that Army recruits learn in basic training.

And never leaving a fallen comrade is also the rule for some warriors who are ants, according to a report published Wednesday in the journal Science Advances.

These ants, Megaponera analis, hunt and eat termites. Scouts will go out, find a group of termites, and then return to the ant nest to muster the troops.

Biologist Erik Frank explains that 200 to 500 ants will march out in formation. “Like three ants next to each other, in a 2-meter-long column,” he says. “It’s very peculiar and it looks like a long snake walking on the ground.”

When the termites spot this invading army, they try to escape, but the fighting is fierce.

“And after roughly 20 minutes the battle is over,” says Frank, a doctoral student with the University of Würzburg in Germany who is researching animal behavior and evolution. “You have a lot of termites lying dead on the ground,” he says, “and the ants start collecting the termites to return.”

A few years ago, Frank was working at a field station in the Ivory Coast when he noticed that some of the ants marching home after battle weren’t carrying termites. Instead, they were carrying other ants.

“And I was wondering, ‘What exactly was going on there? Why were they carrying some of the ants?'” he recalls.

It turns out, those transported ants weren’t dead — they were injured.

Ants sometimes lose a leg or two, which makes it hard for them to walk. Or, they can be weighed down by a dead termite whose jaws had clamped onto them. Either way, they’re slower than uninjured, unburdened ants.

By marking these injured ants with paint, Frank learned that in nearly all cases, they made a full recovery after being carried home to recuperate. They learn to walk with fewer legs, and their ant buddies apparently will pull off stuck termites. It doesn’t take long for an ant that’s been hurt to once again be ready for action.

Credit: Frank et al./Science Advances

“We saw them again, participating in hunts the next day,” says Frank.

He and his colleagues did some experiments to see what would happen to injured ants that weren’t carried home. It turns out that these poor ants couldn’t march fast enough. So they fell behind — and frequently got eaten by spiders and other predators, the researchers report.

From Science Advances:

Saving the injured: Rescue behavior in the termite-hunting ant Megaponera analis

Erik Thomas Frank, Thomas Schmitt, Thomas Hovestadt, Oliver Mitesser, Jonas Stiegler and Karl Eduard Linsenmair

12 April 2017

Abstract

Predators of highly defensive prey likely develop cost-reducing adaptations. The ant Megaponera analis is a specialized termite predator, solely raiding termites of the subfamily Macrotermitinae (in this study, mostly colonies of Pseudocanthotermes sp.) at their foraging sites.

The evolutionary arms race between termites and ants led to various defensive mechanisms in termites (for example, a caste specialized in fighting predators). Because M. analis incurs high injury/mortality risks when preying on termites, some risk-mitigating adaptations seem likely to have evolved.

We show that a unique rescue behavior in M. analis, consisting of injured nestmates being carried back to the nest, reduces combat mortality. After a fight, injured ants are carried back by their nestmates; these ants have usually lost an extremity or have termites clinging to them and are able to recover within the nest.

Injured ants that are forced experimentally to return without help, die in 32% of the cases. Behavioral experiments show that two compounds, dimethyl disulfide and dimethyl trisulfide, present in the mandibular gland reservoirs, trigger the rescue behavior.

A model accounting for this rescue behavior identifies the drivers favoring its evolution and estimates that rescuing enables maintenance of a 28.7% larger colony size. Our results are the first to explore experimentally the adaptive value of this form of rescue behavior focused on injured nestmates in social insects and help us to identify evolutionary drivers responsible for this type of behavior to evolve in animals.

Megaponera analis lives in Africa.

Triassic dinosaur predecessors, new research


This video says about itself:

Meet Teleocrater, a Croc-Like Early Dinosaur Relative

12 April 2017

A 245-million-year-old creature with crocodilian-like legs is an early relative of dinosaurs.

From Virginia Tech in the USA:

Early dinosaur cousin had a surprising croc-like look

Paleobiologist’s latest discovery of Teleocrater rhadinus has overturned popular predictions

April 12, 2017

Summary: Teleocrater and other recently discovered dinosaur cousins show that these animals were widespread during the Triassic Period and lived in modern day Russia, India, and Brazil. Furthermore, these cousins existed and went extinct before dinosaurs even appeared in the fossil record.

For decades, scientists have wondered what the earliest dinosaur relatives looked like. Most assumed that they would look like miniature dinosaurs, be about the size of a chicken, and walk on two legs.

A Virginia Tech paleobiologist’s latest discovery of Teleocrater rhadinus, however, has overturned popular predictions. This carnivorous creature, unearthed in southern Tanzania, was approximately seven to 10 feet long, with a long neck and tail, and instead of walking on two legs, it walked on four crocodylian-like legs.

The finding, published in the journal Nature April 12, fills a critical gap in the fossil record. Teleocrater, living more than 245 million years ago during the Triassic Period, pre-dated dinosaurs. It shows up in the fossil record right after a large group of reptiles known as archosaurs split into a bird branch (leading to dinosaurs and eventually birds) and a crocodile branch (eventually leading to today’s alligators and crocodiles). Teleocrater and its kin are the earliest known members of the bird branch of the archosaurs.

“The discovery of such an important new species is a once-in-a-lifetime experience,” said Sterling Nesbitt, an assistant professor of geosciences in the College of Science.

He and Michelle Stocker, a co-author and also an assistant professor of geosciences in the College of Science, will give a free public talk with the fossils at 7 p.m. Thursday, April 13, 2017 at the Virginia Tech Museum of Geosciences on the second floor of Derring Hall.

Teleocrater fossils were first discovered in Tanzania in 1933 by paleontologist F. Rex Parrington, and the specimens were first studied by Alan J. Charig, former Curator of Fossil Reptiles, Amphibians and Birds at the Natural History Museum of London, in the 1950s.

Largely because the first specimen lacked crucial bones, such as the ankle bones, Charig could not determine whether Teleocrater was more closely related to crocodylians or to dinosaurs. Unfortunately, he died before he was able to complete his studies. The new specimens of Teleocrater, found in 2015, clear those questions up. The intact ankle bones and other parts of the skeleton helped scientists determine that the species is one of the oldest members of the archosaur tree and had a crocodylian look.

Nesbitt and co-authors chose to honor Charig’s original work by using the name he picked out for the animal, Teleocrater rhadinus, which means “slender complete basin” and refers to the animal’s lean build and closed hip socket.

“The discovery of Teleocrater fundamentally changes our ideas about the earliest history of dinosaur relatives,” said Nesbitt. “It also raises far more questions than it answers.”

“This research sheds light on the distribution and diversity of the ancestors of crocodiles, birds, and dinosaurs,” says Judy Skog, program director in the National Science Foundation’s Division of Earth Sciences, “and indicates that dinosaur origins should be re-examined now that we know more about the complex history and traits of these early ancestors.”

Teleocrater and other recently discovered dinosaur cousins show that these animals were widespread during the Triassic Period and lived in modern day Russia, India, and Brazil. Furthermore, these cousins existed and went extinct before dinosaurs even appeared in the fossil record.

The team’s next steps are to go back to southern Tanzania this May to find more remains and missing parts of the Teleocrater skeleton. They will also continue to clean the bones of Teleocrater and other animals from the dig site in the paleontology preparation lab in Derring Hall.

“It’s so exciting to solve puzzles like Teleocrater, where we can finally tease apart some of these tricky mixed assemblages of fossils and shed some light on broader anatomical and biogeographic trends in an iconic group of animals,” said Stocker.

Stocker and Nesbitt are both researchers with the Global Change Center at Virginia Tech. Other co-authors on the paper include: Richard J. Butler with the University of Birmingham; Martin D. Ezcurra with Museo Argentino de Ciencias Naturales; Paul M. Barrett with the Natural History Museum of London; Kenneth D. Angielczyk with the Field Museum of Natural History; Roger M. H. Smith with the University of the Witwatersrand and Iziko South African Museum; Christian A. Sidor with the University of Washington; Grzegorz Niedzwiedzki with Uppsala University; Andrey G. Sennikov with Borissiak Paleontological Institute and Kazan Federal Univeristy; and Charig.

The research was funded by the National Science Foundation, National Geographic Society, a Marie Curie Career Integration Grant, a National Geographic Society for Young Explorers grant, and the Russian Government Program of Competitive Growth of Kazan Federal University.

See also here.