Paleocene mammal fossil discovery


A modern-day pangolin (Manis pentadactyla) skeleton (top) and the ancient Ernanodon antelios (bottom). CREDIT: © Peter Kondrashov

From Discovery News:

Post-Dinos Mammal Was Fat and Slow

This mammal wasn’t much of a runner. But with the dinosaurs gone, it really didn’t need to be.

By Jennifer Viegas

Tue Sep 11, 2012 06:46 AM ET

Many of the mammals that emerged right after the non-avian dinosaur extinction were hearty creatures, as exemplified by Ernanodon, a beast described in the latest issue of the Journal of Vertebrate Paleontology.

The skeleton that is the focus of the study is nearly complete, revealing how this early mammal looked in the flesh and lived.

“Ernanodon was a badger-sized, rather chunky mammal with a short square skull, extremely reduced dentition and big claws on the forelimbs,” lead author Peter Kondrashov told Discovery News.

The structure of the forelimb indicates that this animal was doing a lot of digging, probably mostly in the search of food,” added Kondrashov, who is an associate professor and chair of the Anatomy Department at the Kirksville College of Osteopathic Medicine.

He and colleague Alexandre Agadjanian analyzed the skeleton, which dates to the Late Paleocene (60 to 55 million years ago). This Ernanodon individual lived in Mongolia. Other, less complete, remains were previously found in China.

“Ernanodon is a unique find and represents one of the most complete skeletons ever collected from the Paleocene of the Naran Bulak locality,” said Agadjanian, who works at the Borissiak Paleontological Institute of the Russian Academy of Sciences.

The animal’s hind limbs were almost flat-footed, so the researchers don’t think Ernanodon was much of a runner. It instead appears to have spent most of its days digging and eating, without much chomping.

“Based on the structure of the teeth — very thin enamel layer, reduced tooth size — it appears that the food was rather soft and did not require a lot of chewing,” Kondrashov explained. “Similar dental structure is observed in mammals that feed on termites, ants and other social insects, so we think that it was specialized in feeding on social insects as well.”

While Ernanodon is long gone and has no direct descendants, the scientists believe this animal was related to a group of extinct mammals known as palaeanodonts. They too had bulky bodies, tiny teeth, and big claws for digging.

These animals are, in turn, related to modern mammals called pangolins, or scaly anteaters, which live in Africa and Asia.

Based on the earlier evidence for Ernanodon, scientists thought the then enigmatic mammal was related to modern armadillos or sloths. While pangolins somewhat resemble these animals in appearance and behavior, they represent a different genus and species.

Ernanodon is just one of many mammals that came to prominence after the great non-avian dinosaur extinction.

“This animal comes from the time period known as the Paleocene, which followed the Cretaceous, so it probably evolved as a result of appearance of numerous new niches after the dinosaurs went extinct,” Kondrashov said.

“We know very little about Paleocene deposits in Asia,” he added, “and this find sheds a lot of light on the early evolution of mammals in Asia.”

See also here.

Dinosaur-age Argentinian mammal discovery


Reconstruction of Cronopio dentiacutus in its native environment during the early Late Cretaceous. Image: Jorge Gonzalez/Guillermo Rougier

From New Scientist:

Sabre-toothed squirrel scurried at dinosaurs’ feet

18:00 02 November 2011 by Colin Barras

Truth is sometimes just as strange as fiction. Palaeontologists have unearthed fossils of a bizarre mammal that lived in the shadow of the dinosaurs and was a dead ringer for the sabre-toothed squirrel star of the computer-animated Ice Age films.

Mammals were a fixture of the dinosaur era, but their remains are rarely preserved. The new fossil, which comes from 95-million-year-old rocks in Argentina, is a tantalising sign of what we are missing. Its 2-centimetre-long skull has large eye sockets, a narrow snout and a formidable pair of long canines unlike anything seen before in Mesozoic mammals.

At the time this creature, dubbed Cronopio, roamed Earth, the marsupial and placental mammals that dominate today had already begun to branch out. But Cronopio was a more primitive beast. Its discovery confirms that early mammals tried out body shapes for which no living parallel exists, says Guillermo Rougier at the University of Louisville in Kentucky, whose team made the find.

Cronopio was dug out of rocks rich in the remains of giant sauropod and theropod dinosaurs. Its large eye sockets indicate it was possibly nocturnal, says Christian de Muizon at the Museum of Natural History in Paris, France, who was not a member of Rougier’s team. “The function of the long canines is difficult to assess,” says Rougier. “There is no real modern model for that.”

The shape of the squirrel’s molars suggests that it may have had a taste for insects, he adds. Rougier named the fossil after fictional characters in the novels of Argentinian writer Julio Cortázar, but he is well aware of its silver screen doppelgänger. “Some ridiculous-looking cartoon characters can sometimes be found later as real fossils,” he says.

Journal reference: Nature, DOI: 10.1038/nature10591.

See also here. And here. And here.

Recently announced findings, published in the journal Science by Maureen O’Leary and colleagues, represent an important step in understanding the early evolution of placental mammals, and sheds light on its relation to the mass extinction of dinosaurs. The scientists report that the majority of living mammals evolved at an explosive rate following the extinction of the dinosaurs some 65 million years ago: here.

Giant snake ate fossil crocodiles


This video is called Titanoboa – The World’s Largest Snake.

From LiveScience:

45-foot Ancient Snake Devoured Giant Crocs

By LiveScience Staff

posted: 03 February 2010 10:50 am ET

The largest snake the world has ever known likely had a diet that included crocodile, or at least an ancient relative of [that] reptile.

Scientists have discovered a 60-million-year-old ancient crocodile fossil, which has been named a new species, in northern Columbia, South America. The site, one of the world’s largest open-pit coal mines, also yielded skeletons of the giant, boa constrictor-like Titanoboa, which measured up to 45 feet long (14 m).

Crocodyliforms are extinct reptiles that are distant relatives of modern crocodiles and alligators.

“We’re starting to flesh out the fauna that we have from there,” said study author Alex Hastings, a graduate student at the Florida Museum of Natural History.

Specimens used in the study show the new species, named Cerrejonisuchus improcerus, grew only 6 to 7 feet long (about 2 m), making it easy prey for Titanoboa.

Clearly this new fossil would have been part of the food-chain, both as predator and prey,” said Jonathan Bloch, a Florida Museum vertebrate paleontologist and associate curator. “Giant snakes today are known to eat crocodylians, and it is not much of a reach to say Cerrejonisuchus would have been a frequent meal for Titanoboa. Fossils of the two are often found side-by-side,” added Bloch, who was part of the fossil-hunting expeditions.

Indeed, anacondas have been documented consuming caimans — reptiles in the same family as crocodiles — in the Amazon.

The new croc species is the smallest member of Dyrosauridae, a family of now-extinct crocodyliforms. Dyrosaurids typically grew to about 18 feet and had long tweezer-like snouts for eating fish. By contrast, the newly discovered species had a much shorter snout, indicating a more generalized diet that likely included frogs, lizards, small snakes and possibly mammals.

“It seems that Cerrejonisuchus managed to tap into a feeding resource that wasn’t useful to other larger crocodyliforms,” Hastings said.

The study reveals an unexpected level of diversity among dyrosaurids, said Christopher A. Brochu, a paleontologist at the University of Iowa, who was not involved in the study.

Scientists previously believed dyrosaurids diversified in the Paleogene, the period of time following the mass extinction of dinosaurs. But this study reinforces the view that much of their diversity was in place before the mass extinction event, Brochu said. Somehow dyrosaurids survived the mass extinction intact while other marine reptile groups, such as mosasaurs and plesiosaurs, died out completely.

The study was published in the Journal of Vertebrate Paleontology.

See also here.

Thought to be a distant relative of the anaconda and boa constrictor, the snake – named Titanoboa – was not venomous. Instead, it crushed its prey with the constricting force of 400lbs per sq inch – the equivalent of lying under the weight of one and a half times the Brooklyn Bridge: here.

Are Anacondas Really Capable of Devouring a Human? Here.

Population Structure and Gene Flow of the Yellow Anaconda (Eunectes notaeus) in Northern Argentina: here.

The reticulated python is (barely) the world’s longest snake, but the green anaconda is almost 2x as heavy: here.

New snake identification guide can help Florida residents enjoy the outdoors: here.

Discarded Burmese pythons hunt Florida mammals to brink of extinction: here.

May 2013. A Miami man has caught and killed the longest Burmese python ever captured in Florida, measuring 18 feet, 8 inches. The python was a 128-pound female that was not carrying eggs, according to University of Florida scientists who examined the snake. The previous record length for a Burmese python captured in the wild in Florida was 17 feet, 7 inches: here.

Smooth green snakes in the USA: here.

Georgia alligator spotted 20 miles out to sea: here.

Smooth snake: here. And here.

Devon project boosts rare smooth snake: here.

Moroccan elephant ancestor discovered


Elephant ancestorsBy Jeanna Bryner, of LiveScience, in the USA:

Fossils of oldest elephant relative found

60-million-year-old remains show much smaller tusks than current animals’

June 22, 2009

Scientists have discovered fossilized remains of the oldest known elephant relative, dating back 60 million years.

The fossils were found in Morocco. Called Eritherium azzouzorum, the animal would not have looked much like an elephant. It was just 1.6 to 2 feet (50 to 60 cm) long and weighed 9 to 11 pounds (4 to 5 kg).

The animal’s relation to elephants was determined via analysis of the specimen’s teeth and skull. While it lacked a trunk, the animal had an enlarged first incisor, which researcher Emmanuel Gheerbrant of the National Museum of Natural History in Paris says represents a primitive tusk. It was much smaller than the tusks of today’s elephants.

“The trunk evolved with the modern elephant group, called elephantiform, at the beginning of the Oligocene,” which extends from 33.7 million to 23.8 million years ago, Gheerbrant told LiveScience.

The fossil mammal was found in the same area that yielded the then-oldest elephant relative called Phosphatherium escuilliei, which dated back 55 million years.

The newly identified species extends the record of the Proboscidea order (whose sole survivors today are modern elephants) back to the Late Paleocene.

The research was published in the June 22 issue of the journal Proceedings of the National Academy of Sciences.

Jon Smith, a scientist at the Kansas Geological Survey, and Stephen Hasiotis, a geologist at the University of Kansas, have demonstrated that soil-inhabiting creatures contracted in size by 30-46 percent during the Palaeocene-Eocene Thermal Maximum (PETM). The PETM was a short interval 55 million years ago marked by a spike in the atmosphere’s carbon dioxide levels and global temperatures, conditions being repeated on Earth now: here.

Seventeen species from the Palaeocene and Early Eocene of northern Europe, of which 12 are new, are described belonging to the extinct macroscelidean family Louisinidae, raised here from subfamily rank. These species belong to nine genera, of which five are new. The new genera are Walbeckodon, Berrulestes, Gigarton, Thryptodon, and Prolouisina. The new species are Walbeckodon krumbiegeli, Walbeckodon girardi, Paschatherium levei, Berrulestes phelizoni, Berrulestes pellouini, Berrulestes poirieri, Gigarton meyeri, Gigarton sigogneauae, Gigarton louisi, Thryptodon brailloni, Louisina marci, and Teilhardimys brisswalteri. Prolouisina is erected for ‘Louisina’atavella Russell, 1964. Cladistic analysis was undertaken to understand the relationships within the Louisinidae and between them and the North American family Apheliscidae, in which they had earlier been included as a subfamily. Louisinidae are shown to be sister group to a clade consisting of Apheliscidae plus Amphilemuridae and part of a paraphyletic and polyphyletic Adapisoricidae, all of which are tentatively considered to be stem members of the order Macroscelidea. The most primitive macroscelidid, Chambius, from the Early Eocene of northern Africa is nested within Apheliscidae when postcranial characters were included, but in a majority of cases within the Louisinidae when postcranial characters were excluded. Most species from northern Europe became extinct at the end of the Palaeocene, although the genus Paschatherium survived for much of the Early Eocene and Teilhardimys survived into the earliest Eocene: here.

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Giant mono-cellular discoveries


This video from Texas, USA, is called Invertebrate Fossils – Lesson 16 – Part 2 of 7.

From the University of Texas at Austin in the USA:

Discovery of giant roaming deep sea protist provides new perspective on animal evolution

AUSTIN, Texas—Groove-like tracks on the ocean floor made by giant deep-sea single-celled organisms could lead to new insights into the evolutionary origin of animals, says biologist Mikhail “Misha” Matz from The University of Texas at Austin.

Matz and his colleagues recently discovered the grape-sized protists and their complex tracks on the ocean floor near the Bahamas. This is the first time a single-celled organism has been shown to make such animal-like traces.

The finding is significant, because similar fossil grooves and furrows found from the Precambrian era, as early as 1.8 billion years ago, have always been attributed to early evolving multicellular animals.

“If our giant protists were alive 600 million years ago and the track was fossilized, a paleontologist unearthing it today would without a shade of doubt attribute it to a kind of large, multicellular, bilaterally symmetrical animal,” says Matz, an assistant professor of integrative biology. “We now have to rethink the fossil record.”

The team’s discovery was published online today in Current Biology and will appear in a subsequent print issue.

Most animals, from humans to insects, are bilaterally symmetrical, meaning that they can be roughly divided into halves that are mirror images.

The bilateral animals, or “Bilateria,” appeared in the fossil record in the early Cambrian about 542 million years ago, quickly diversifying into all of the major animal groups, or phyla, still alive today. This rapid diversification, known as the Cambrian explosion, puzzled Charles Darwin and remains one of the biggest questions in animal evolution to this day.

Very few fossils exist of organisms that could be the Precambrian ancestors of bilateral animals, and even those are highly controversial. Fossil traces are the most accepted evidence of the existence of these proto-animals.

“We used to think that it takes bilateral symmetry to move in one direction across the seafloor and thereby leave a track,” explains Matz. “You have to have a belly and a backside and a front and back end. Now, we show that protists can leave traces of comparable complexity and with a very similar profile.”

“I personally think now that the whole Precambrian may have been exclusively the reign of protists,” says Matz. “Our observations open up this possible way of interpreting the Precambrian fossil record.”

He says the appearance of all the animal body plans during the Cambrian explosion might not just be an artifact of the fossil record. There are likely other mechanisms that explain the burst-like origin of diverse multicellular life forms.

DNA analysis confirmed that the giant protist found by Matz and his colleagues in the Bahamas is Gromia sphaerica, a species previously known only from the Arabian Sea.

They did not observe the giant protists in action, and Matz says they likely move very slowly. The sediments on the ocean floor at their particular location are very stable and there is no current—perfect conditions for the preservation of tracks.

Matz says the protists probably move by sending leg-like extensions, called pseudopodia, out of their cells in all directions. The pseudopodia then grab onto mud in one direction and the organism rolls that way, leaving a track.

He aims to return to the location in the future to observe their movement and investigate other tracks in the area.

Matz says the giant protists’ bubble-like body design is probably one of the planet’s oldest macroscopic body designs, which may have existed for 1.8 billion years.

“Our guys may be the ultimate living fossils of the macroscopic world,” he says.

See also here.

Pre-palaeozoic rocks: here.

Pre-Cambrian plants: here.

Pre-Cambrian animal evolution: here.

Early Palaeozoic Ice Age: here.

Fresh clues hint at how the first living organisms arose from inanimate matter: here.

Palaeontologists have discovered a new fossil species called Cloudina carinata, a small fossil with a tubular appearance and one of the first animals that developed an external skeleton between 550 and 543 million years ago. The discovery is documented in Precambrian Research: here.

2-billion-year-old fossilised blobs could be oldest known multicellular life: here.

Why complex life probably evolved only once – and why it’s unlikely to exist elsewhere: here.

Oceans may have poisoned early animals: Add sulfur, subtract oxygen, and a deadly brew results: here.

The discovery of leaf-thin, seaweed-like fossils in China nudges back the moment when ancient life went from microscopic to merely tiny. At 600 million years old, the new fossils—called the Lantian Formation—are 27 million years older than the so-called Avalon fossils found in Canada and England, which, until now, were the earliest known fossil assemblage of multicellular life: here.

Pools of water on land were a lot livelier 1 billion years ago than previously thought: here.

Animals living more than 550 million years ago could have survived inhospitable oceans by associating with dense mounds of cyanobacteria called microbial mats, an international team of researchers argues in a new study. Such clumps of oxygen-producing gunk could have supplied the first mobile animals with food to eat and air to breathe, the group reports online May 15 in Nature Geoscience: here.

“The origin of life is not just asteroids and comets”: here.

For centuries scholars sought to determine the earth’s age, but the answer had to wait for careful geologic observation, isotopic analyses of the elements and an understanding of radioactive decay: here.