Common ancestor of all wildlife, new research


This video says about itself:

Scientists Reveal LUCA – Common Ancestor Of All Living Things On Earth

26 July 2016

Many scientists believe that all living entities on Earth originated from an ancient organism called Luca which stands for the Last Universal Common Ancestor. Now, a team led by William F. Martin of Heinrich Heine University has released a new study which aims to “reconstruct the microbial ecology of LUCA.”

Many scientists believe that all living entities on Earth originated from an ancient organism called Luca which stands for the Last Universal Common Ancestor. The single-celled being likely lived around 4 billion years ago and is thought to have eventually spawned two distinct groups of uni-celled life–bacteria and archaea.

Now, a team led by William F. Martin of Heinrich Heine University has released a new study which aims to “reconstruct the microbial ecology of LUCA.” For the research, they tested 286,514 protein clusters and found that 355 protein families likely descended from the organism. Based on the attributes of this select group, the scientists theorize that Luca was able to withstand hot temperatures and live on hydrogen and carbon dioxide instead of oxygen; it also needed metals to be in the surrounding environment.

These combined attributes seem to indicate that this so-called universal ancestor lived in a habitat similar to a hot and gassy deep-sea vent. Despite the team’s findings, critics point out that additional information is needed to prove where life began.

From Nature Microbiology:

The physiology and habitat of the last universal common ancestor

Published online: 25 July 2016

Abstract

The concept of a last universal common ancestor of all cells (LUCA, or the progenote) is central to the study of early evolution and life’s origin, yet information about how and where LUCA lived is lacking.

We investigated all clusters and phylogenetic trees for 6.1 million protein coding genes from sequenced prokaryotic genomes in order to reconstruct the microbial ecology of LUCA. Among 286,514 protein clusters, we identified 355 protein families (∼0.1%) that trace to LUCA by phylogenetic criteria. Because these proteins are not universally distributed, they can shed light on LUCA’s physiology.

Their functions, properties and prosthetic groups depict LUCA as anaerobic, CO2-fixing, H2-dependent with a Wood–Ljungdahl pathway, N2-fixing and thermophilic. LUCA’s biochemistry was replete with FeS clusters and radical reaction mechanisms. Its cofactors reveal dependence upon transition metals, flavins, S-adenosyl methionine, coenzyme A, ferredoxin, molybdopterin, corrins and selenium. Its genetic code required nucleoside modifications and S-adenosyl methionine-dependent methylations. The 355 phylogenies identify clostridia and methanogens, whose modern lifestyles resemble that of LUCA, as basal among their respective domains.

LUCA inhabited a geochemically active environment rich in H2, CO2 and iron. The data support the theory of an autotrophic origin of life involving the Wood–Ljungdahl pathway in a hydrothermal setting.

See also here.

Mammoth bone found on Texel island beach


The mammoth bone and its discoverers, with a woolly rhino model in the background, photo Ecomare museum

Translated from Dutch NOS TV:

Family finds mammoth bone during holiday on Texel

Today, 12:42

A family from Gouda found a mammoth bone tens of thousands of years old during a walk on the beach of Texel. Arieke Visscher and her daughters Francine and Ruth made the discovery at beach post 28, the regional broadcasting organisation NH writes.

Mother Arieke thought almost immediately that it was a mammoth bone. Her grandfather was a fisherman and fished these bones from the sea.

Fibula

A curator of Ecomare museum established that it was indeed a mammoth bone. Presumably it is a piece of a fibula. The bone is from the last ice age, about 20,000 to 40,000 years ago.

The bones of mammoths are still found at the bottom of the sea. The bones end up on the beach and North Sea sand is used for widening the beach. The discovery on the island, according to Ecomare therefore is “not very special, but still very nice.”

Triceratops dinosaur fossils, from the USA to Dutch museum


After the earlier video about this on this blog, these Dutch videos are about people from Naturalis museum in Leiden in the Netherlands going to the USA to fetch Triceratops dinosaur fossils.

This 15 July 2016 video is the most recent one of the series.

Dinosaur extinction, new theory


This 2015 video is called National Geographic Documentary: Extinction Of Dinosaurs. What About Killer Dinosaurs.

From daily The Independent in Britain:

Dinosaur extinction mystery solved? Asteroid hit oil field causing smoke that filled Earth’s atmosphere

Temperatures would have plunged as soot blocked out the sun and the rain virtually stopped falling

Ian Johnston, Science Correspondent

21 minutes ago

The dinosaurs were wiped out 66 million years ago because a massive asteroid hit vast oil deposits in Mexico, sending thick black smoke into the atmosphere all over the world, according to a new study.

Soot blocked out the sun, causing the planet to cool significantly and experience devastating droughts.

The amount of sunlight would have fallen by up to 85 per cent, while the Earth would have cooled by as much as 16 degrees Celsius on land for about three years.

At the same time, rainfall would have fallen by up to 80 per cent causing extreme drought.

In a paper in the journal Scientific Reports, the researchers wrote: “Although small mammals and reptiles could have lived underground where it is warmer, the dinosaurs did not.

“The different habitats of the dinosaurs and small mammals and reptiles would also have been key factors in determining their extinction or survival.”

The six-mile-wide asteroid, which hit what is now the Yucatan Peninsula, created the third-largest crater on Earth, some 110 miles across.

It struck the Earth with the force of about a billion nuclear bombs of the size that destroyed the Japanese city of Hiroshima during World War Two.

It had been something of a mystery why some dinosaurs had died out while others, like the ancestors of crocodiles,

The ancestors of crocodiles were not dinosaurs. Though, like dinosaurs, they belonged to the bigger group called archosaurs.

did not.

Previously it was thought that the impact caused vapours of sulphuric acid in the sky, which reflected sunlight leading to global darkness, near-freezing conditions and widespread acid rain.

But the researchers, from Japan’s Meteorological Research Institute and Tohuku Univeristy, said: “If this had occurred, crocodilians and various other animals would have also gone extinct.

“Recent impact experiments and model calculations have demonstrated that condensed sulfuric acid aerosols cannot form and persist over long periods following asteroid impacts.”

It is estimated that just 12 per cent of life on land survived the chaos unleashed by the asteroid, but 90 per cent of freshwater species were able to ride out the sudden shock to the planet.

Unusual carnivorous dinosaur described


This video says about itself:

13 July 2016

A newly discovered meat-eating dinosaur that prowled Argentina 90 million years ago would have had a hard time using strong-arm tactics against its prey. That’s because the beast, though a fearsome hunter, possessed a pitifully puny pair of arms.

Scientists said on Wednesday they have unearthed fossils in northern Patagonia of a two-legged, up to 26-foot-long (8-meters-long) predator called Gualicho shinyae with arms only about 2 feet (60 cm) long, akin to a human child’s.

The fossils of Gualicho, named after an evil spirit feared by Patagonia’s indigenous Tehuelche people, were discovered in Argentina’s Rio Negro Province.

Gualicho and other carnivorous dinosaurs like Tyrannosaurus rex are part of a group called theropods that included Earth’s largest-ever land predators. But a curious thing happened during their many millions of years of evolution. For some, as they acquired huge body size and massive skulls, their arms and their number of fingers shrank.

From the Christian Science Monitor in the USA:

T. rex wasn’t the only one with those strange little arms

Paleontologists discover a new dinosaur with T. rex-like arms, but it’s not a tyrannosaur.

By Eva Botkin-Kowacki, Staff writer

July 13, 2016

Quick! Make like a T. rex.

What is the first step to mimicking the famous, fearsome dinosaur? After roaring, a person probably pulls both arms in, contorting them to make them tiny relative to the rest of the body, mashing the five fingers together to have just two digits on each hand. One of the most characteristic features of the iconic tyrant lizard dinosaur is its strange, seemingly uselessly small forelimbs.

But Tyrannosaurus rex wasn’t the only two-legged carnivorous dinosaur to sport such teeny, two-fingered arms.

“Theropods in general do this quite often,” Lindsay Zanno, head of the Paleontology Research Lab at the North Carolina Museum of Natural Sciences, tells The Christian Science Monitor in a phone interview. “There are a lot of different groups of theropods that tend to reduce the size of their hands and their arms or change the way that they’re used.”

And another one is joining the bunch.

Gualicho shinyae, discovered in Argentina in 2007, is named and described in a paper published Wednesday in the journal PLOS ONE.

This new dinosaur’s “arms are short – about 2 ft long – which is less than the length of the thigh bone, and they have weak muscle attachments and poorly developed articulations indicating they had little strength,” Peter Makovicky, associate curator of dinosaurs at the Field Museum of Natural History in Chicago who co-led the team that discovered Gualicho, describes in an email to the Monitor.

The fingers on the 90-million-year-old fossil are similar to those of tyrannosaurs. The thumb has a large claw while the second finger is more slender. A third finger has become so reduced that it is just a tiny bone in the flesh of the animal’s hand. …

Gualicho has weak little arms with just two functional fingers like T. rex, but the similarities pretty much stop there.

“This animal has a kind of mosaic of features. There are aspects of its skeleton that show some affinities with some groups of dinosaurs and some affinities with other groups of dinosaurs, although none of those are really tyrannosaurs,” study co-author Nathan Smith, associate curator in the Dinosaur Institute at the Natural History Museum of Los Angeles County, tells the Monitor in a phone interview.

But the “oddball” dinosaur, as Dr. Smith describes it, could help researchers figure out why so many diverse theropod dinosaurs have evolved similar, reduced forelimbs. …

Some scientists have suggested that humongous predatory dinosaurs would have evolved smaller arms because their skulls were used more readily to wrangle prey, she says.

There seems to be a pattern among tyrannosaurs, for example, in which the arms became shorter and the fingers fewer as the animals’ skulls and bodies became larger over generations, says Stephen Brusatte, a paleontologist at the University of Edinburgh who was not part of the study, in an email to the Monitor. This would suggest that “the head was taking over many of the duties that the arms once had, like procuring and processing food.”

“Most theropods with reduced forelimbs, like tyrannosaurs, ceratosaurs, and carcharodontosaurs are clearly macropredators that rely on their massive skulls for hunting, so it seems likely that the same was true of Gualicho,” Makovicky says.

These diverse dinosaurs were likely under similar evolutionary pressures that lead to similarly reduced forelimbs. The feature would have evolved independently in the different groups, in a process called convergent evolution. …

The mosaic features of Gualicho “makes figuring out the evolutionary placement of this animal a little difficult,” Smith says.

Weighing an estimated 1,000 pounds, Gualicho appears to fit into the family neovenatoridae, a large-bodied branch of carnivorous theropod dinosaurs, Smith says, but it also seems to bear the closest resemblance to Deltadromeus, a large theropod from Africa.

But could a South American dinosaur be closely related to an African one?

Possibly. Scientists have previously noted a lot of similarities between dinosaurs unearthed in the Kem Kem Beds on the border of Morocco and Algeria, where Deltadromeus has been found, and the Huincul Formation in Argentina, where Guialicho was discovered, Smith says. “So it may not be surprising that these two carnivorous dinosaurs are close relatives.”

And at the time when Guialicho roamed the Earth, the two continents had only recently, geologically speaking, begun to separate as the supercontinent Gondwana broke up.

New Triassic marine reptile species discovery


This 2012 video, in Italian, is about Lariosaurus valceresii and Lariosaurus balsami Triassic marine reptiles.

Translated from Dutch NOS TV:

Amateur paleontologist finds skull of prehistoric reptile

Today, 06:05

Never before the animal had been found in the Netherlands; Lariosaurus. Now a 4.5 centimeter skull of the flippered fish-eater has been found in a quarry in Winterswijk.

Amateur paleontologist Remco Bleeker was the lucky one who found the skull. Bleeker, in everyday life a concrete repairer, is pleased with the find. …

Bleeker brought the skull for examination to Germany, where it was found that it was a Lariosaurus.

Muschelkalk

In the quarry at Winterswijk Triassic limestone is extracted from rock layers from the Triassic geological period some 240 million years ago. In the quarry Bleeker also once found a peculiar fossil of a toothy marine animal. This fossil, which was seen by experts as a missing link was even named after him: the Palatodonta bleekeri.

The skull of the lariosaurus has been given the name of the hamlet where it was found. “The first is named after me. Now it was time to honor the quarry,” says Bleeker, who gave his find on loan to Museum TwentseWelle.

The name of the newly discovered species is Lariosaurus vosseveldensis; after Vosseveld hamlet.

See also here.

The scientific description of the new species is here.

Triceratops dinosaur expedition video


This 14 June 2016 video is from Naturalis museum in Leiden in the Netherlands. It shows how a paleontologist prepares to go to Wyoming in the USA for excavating Triceratops dinosaur fossils.