Category Archive 'Paleontology'
23 May 2017

Settled Science

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16 May 2017

When Exactly Did Humans Arrive in North America?

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San Diego Natural History Museum Paleontologist Don Swanson pointing at a large horizontal mastodon tusk fragment.

Wired reports on a fossil find near San Diego from the 1990s that may completely upset the chronological apple cart.

In 1993, construction workers building a new freeway in San Diego made a fantastic discovery. A backhoe operator scraped up a fossil, and scientists soon unearthed a full collection of bones, teeth, and tusks from a mastodon. It was a valuable find: hordes of fossils, impeccably preserved. The last of the mastodons—a slightly smaller cousin of the woolly mammoth—died out some 11,000 years ago.

But the dig site turned out to be even more revelatory—and now, with a paper in the journal Nature—controversial. See, this site wasn’t just catnip for the paleontologists, the diggers who study all fossils. It soon had archaeologists swooping in to study a number of stone tools scattered around the bones, evidence of human activity. After years of debate over the dating technology used on the mastodon, a group of researchers now believes that they can date it and the human tools to 130,000 years ago—more than 100,000 years earlier than the earliest humans are supposed to have made it to North America.

The researchers expect a bit of controversy from a discovery that pushes back the arrival of humans in North America by a factor of ten.

RTWT

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21 Apr 2017

Compare

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16 Feb 2017

Oldest Venomous Critter on Earth

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Euchambersia is a genus of therocephalian therapsid that lived during the Late Permian, approximately 255 million years ago, in what is now South Africa.

Seeker.com:

The oldest venomous vertebrate yet found was a small-dog-sized early relative of mammals named Euchambersia that lived some 260 million years ago, according to findings just published in the journal PLOS One by scientists from University of the Witwatersrand (WITS).

“Today, snakes are notorious for their venomous bite,” said the study’s lead author Julien Benoit in a statement, “but their fossil record vanishes in the depth of geological times at about 167 million years ago. So, at 260 million years ago, the Euchambersia evolved venom – more than a 100 million years before the very first snake was even born.”

Euchambersia was about 16-20 inches long (40-50 centimeters) and trod the land of modern-day South Africa well before the dinosaurs. The animal has long been supposed to have been venomous, based on characteristics of its teeth and upper jaw, but the hypothesis had not until now been tested.

The WITS researchers used CT scanning and 3D imaging on the only two fossilized skulls in existence of Euchambersia. Sure enough, under the detailed examination they found the small creature’s anatomy had characteristics consonant with making venom.

The scientists found a deep, wide space in the upper jaw called a fossa that would have held a venom gland. It was connected to the canine teeth and mouth by bony grooves and canals. Finally, ridges on the incisors and canine teeth completed the venom delivery system.

Euchambersia did not deliver its venom in the same way snakes deliver their payload, the scientists found. While reptiles such as the cobras and vipers we all know and run from today inject venom through needle-like grooves in the their teeth, Euchambersia’s venom went directly into its mouth and the animal used the ridges on its canines to pass the poison to its victims.

Complete story.

12 May 2015

40,000-Year-Old Bracelet Made by Different Hominid Species Found in Siberia

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DenisovianBracelet

Digital Journal:

[S]cientists have confirmed that a bracelet found in Siberia is 40,000 years old. This makes it the oldest piece of jewelry ever discovered, and archeologists have been taken aback by the level of its sophistication.

The bracelet was discovered in a site called the Denisova Cave in Siberia, close to Russia’s border with China and Mongolia. It was found next to the bones of extinct animals, such as the wooly mammoth, and other artifacts dating back 125,000 years.

The cave is named after the Denisovan people — a mysterious species of hominins from the Homo genus, who are genetically different from both Homo sapiens and Neanderthals.

20 Mar 2015

Carolina Butcher

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Carnufex
Carnufex carolinensis

The Guardian has news of the discovery of a very large, bipedal crocodile which once inhabited the Carolinas.

Scientists have unearthed fossils in the United States of a big land-dwelling crocodile that lived about 231 million years ago, walked on its hind legs and was a top land predator right before the first dinosaurs appeared.

Transported back to the Triassic Period, what would a person experience upon encountering this agile, roughly 9-foot-long (about 3 meter-long), 5-foot-tall (about 1.5 meter-tall) beast with a long skull and blade-like teeth?

“Abject terror,” said North Carolina State University paleontologist Lindsay Zanno, who led the research published in the journal Scientific Reports.

“Climb up the nearest tree,” advised North Carolina Museum of Natural Sciences paleontologist Vince Schneider.

The creature is named Carnufex carolinensis, meaning “Carolina butcher,” for its menacing features. It was a very early member of the crocodile lineage and was unlike today’s beasts. It was not aquatic and not a quadruped, instead prowling on two legs in the warm equatorial region that North Carolina was at the time.

16 May 2014

Ice Age Skeleton Found in Cave in Mexico

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HoyoNegro

One of the earliest examples of human remains ever found in the Americas, an Ice Age skeleton, 12,000 to 13,000 years old, of a sixteen-year-old girl was found in 2007 in Hoyo Negro, an underwater cave in Mexico’s Yucatan Peninsula. The cave also contained skeletal remains of saber-toothed tigers, gomphotheres, two species of giant ground sloth (including one previously unknown to Science), cougars, cave bears, coyotes, bats and other small animals. The girl’s skeletal remains were DNA-tested, and her Mitochondrial DNA identified as belonging to Haplogroup D1, one of five haplogroups typical of Native Americans.

National Geographic article & video

Current coverage was occasioned by the appearance of an article in Science.

Hat tip to Karen L. Myers.

09 Nov 2013

Paleontology Cake

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Via I f*cking love science.

08 Oct 2013

“The Crows Were Very Large Near the Old Nuclear Test Sites in Eastern Kazakhstan”

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Actually, a model of a once real bird.

Hat tip to Steve Bodio.

16 Aug 2013

Are Your Children Abusing Rocks?

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Hat tip to Steve Bodio.

30 Jul 2013

Not Only From the Apes…

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Ingrid Newkirk of PETA contends that, really, “A Rat Is a Pig Is a Dog Is a Boy.”

Newkirk’s pig=boy equivalence receives support from Phys.Org, which links a scientific blog-site listing a long series of anatomical comparisons, which it argues constitute evidence that human beings do not only descend from apes.

Dr. Eugene McCarthy is a Ph.D. geneticist who has made a career out of studying hybridization in animals. He now curates a biological information website called Macroevolution.net where he has amassed an impressive body of evidence suggesting that human origins can be best explained by hybridization between pigs and chimpanzees. Extraordinary theories require extraordinary evidence and McCarthy does not disappoint. Rather than relying on genetic sequence comparisons, he instead offers extensive anatomical comparisons, each of which may be individually assailable, but startling when taken together. Why weren’t these conclusions arrived at much sooner? McCarthy suggests it is because of an over-dependence on genetic data among biologists. He argues that humans are probably the result of multiple generations of backcrossing to chimpanzees, which in nucleotide sequence data comparisons would effectively mask any contribution from pig.

Generally speaking, interspecies hybrids—like mules, ligers (lion-tiger hybrids), or zedonks (zebra-donkey hybrids)—are less fertile than the parents that produced them. However, as McCarthy has documented in his years of research into hybrids, many crosses produce hybrids that can produce offspring themselves. The mule, he notes, is an exceptionally sterile hybrid and not representative of hybrids as a whole. When it comes time to play the old nuclear musical chairs and produce gametes, some types of hybrids do a much better job. Liger females, for example, can produce offspring in backcrosses with both lions and tigers. McCarthy also points out that fertility can be increased through successive backcrossing with one of the parents, a common technique used by breeders. In the case of chimp – pig hybridization, the “direction of the cross” would likely have been a male boar or pig (Sus scrofa) with a female chimp (Pan troglodytes), and the offspring would have been nurtured by a chimp mother among chimpanzees (shades of Tarzan!). The physical evidence for this is convincing, as you can discover for yourself with a trip over to macroevolution.net.

When I asked McCarthy if he could give a date estimate for the hybridization event, he said that there are a couple broad possibilities: (1) It might be that hybridization between pigs and apes produced the earliest hominids millions of years ago and that subsequent mating within this hybrid swarm eventually led to the various hominid types and to modern humans; (2) separate crosses between pigs and apes could have produced separate hominids (and there’s even a creepy possibility that hybridization might even still be occurring in regions where Sus and Pan still seem to come into contact, like Southern Sudan).

This latter possibility may not sound so far-fetched after you read the riveting details suggesting that the origin of the gorilla may be best explained by hybridization with the equally massive forest hog. This hog is found within the same habitat as the gorilla, and shares many uncommon physical features and habits. Furthermore, well-known hybridization effects can explain many of the fertility issues and other peculiarities of gorilla physiology.

Read the whole thing.

Via the Dish.

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In the film “Gettysburg” (1993), on the evening of July 2nd, Confederate Corps Commander James Longstreet, Divisional Commander George Pickett and his Brigade Commanders Kemper and Armistead, discuss Charles Darwin’s new scientific theory of Evolution. Personally, I think General Pickett gets the best of the argument.

05 Jul 2013

Kids Find Mastodon Tooth in Iowa Creek

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KWWL story.

Sumner is in Northeastern Iowa.

19 Feb 2013

Too Late For Valentine’s Day, Alas!

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Devonian Comura trilobite from Hamar Laghdad Formation, Erfoud, Morocco

The advertising description reads:

This INVESTMENT GRADE spiny Comura trilobite represents the finest possible quality of preservation, completeness and displays an entire array of authentic spines freed completely from their matrix and exposed. This species is one of the most complex and difficult to prepare in this manner and such a project encompasses untold hours of meticulous preparation and skill. All three rows of spines running down the lobes of this trilobite and all other cephalonic spines have been exposed and are 100% AUTHENTIC. The trilobite is prepared with the head (cephalon) protruding up off of the rock and rock is removed from beneath. This time-consuming fantastic, natural position gives the impression as if it is attempting to crawl off its original limestone matrix. Examples like this come along only on very rare occasion and 100% authentic examples are becoming increasingly difficult to find. Perfect for the most demanding advanced collector striving to acquire specimens based on the finest rarity and quality.

I didn’t actually realize that trilobites came in investment grade, and I bet they didn’t either, but I will gladly concede that is is one heck of a nice trilobite.

The photos don’t really make it clear that this bad boy is only 2.4″ long, and the whole shooting match, rock and all, is less than 3 1/2″ long. Nonetheless, they are asking $4250.

Hat tip to Fred Lapides.

25 Jul 2012

Chromosomal Evidence That Mankind Nearly Went Extinct

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A leading causal candidate for the human genetic bottleneck is the volcanic supereruption that formed Lake Toba in Sumatra, Indonesia.

Sam Kean, in Slate, explains that the number of human chromosomes suggests that modern humanity emerged from a small, inbred population.

Humans have 46 chromosomes. Our closest primate relatives have 48. So where did those extra two disappear to? …

Let’s go back a million years, when most proto-humans had 48 chromosomes, and follow a hypothetical Guy who has 47. Again, a chromosome fused at the tips won’t affect Guy’s day-to-day health. But having an odd number of chromosomes will cripple the viability of his sperm. (If you prefer to think of a female, the same is true of her eggs.)

Say the fusion left Guy with a normal chromosome 12, a normal 13, and a 12-13 hybrid in each cell. During sperm production his body has to divide those three chromosomes into two cells, and there are only a few possible ways to divvy them. There’s {12} & {13, 12-13}, or {13} & {12, 12-13}, or {12, 13} & {12-13}. The first four sperms are either missing a chromosome or have a duplicate, practically a cyanide capsule for an embryo. The last two cases have the proper amount of DNA for a normal child. But only in the sixth case does Guy pass the fusion on. Overall, then, two-thirds of Guy’s children die in the womb, and just one-sixth inherit the fusion. And any Junior with the fusion would then face the same terrible odds trying to reproduce. Not a good recipe for spreading the fusion—and again, that’s still only 47 chromosomes, not 46.

What Guy needs is a Doll with the same two fused chromosomes. Now, the odds of two people with the same fusion meeting might seem infinitesimal. And they would be—except in inbred families, where the chances of finding a cousin or half-sibling with the same fusion don’t round down to zero so easily. What’s more, while the odds of Guy and Doll having a healthy child remain low, every 36th spin of the genetic roulette wheel (because 1/6 x 1/6 = 1/36), the child would inherit both fused chromosomes—giving him 46 total.

And here’s the payoff: Junior and his 46 chromosomes would likely have an easier time having children than his 47-chromosomed parents. Remember that the fusion itself doesn’t ruin you—lots of healthy people have fusions. It’s only reproduction that gets tricky, since fusions can lead to an excess or deficit of DNA in embryos. But because he has an even number of chromosomes, little Junior wouldn’t have any unbalanced sperm cells: Each would have the right amount of DNA to run a human, just packaged differently. As a result, all of his children have a good chance of being healthy. And if his children start having their own children—especially with other relatives with 46 or 47 chromosomes—the fusion could start to spread. …

How did having 46 chromosomes then spread worldwide? It’s possible that having two fewer chromosomes than everyone else gave Guy and Doll’s family a whopping evolutionary advantage, allowing them to out-compete the 48-chromosome sluggards. But probably not. More likely, they happened to be living at a point when the human race nearly got wiped out.

Take your pick for the cause of our near-extinction—ice ages, plagues, Indonesian gigavolcanoes. But humans have far less genetic diversity than most other species, and the most reasonable explanation for this is a genetic bottleneck: a severe reduction in the population of humans in the past, perhaps multiple times. One study suggested that our population, worldwide, might have dropped as low as 40 adults. (The world record for fitting people in a phone booth is 25.) That’s an outlandishly pessimistic guess even among disaster scientists, but it’s common to find estimates of a few thousand adults, below what some minor league baseball teams draw.

Read the whole thing.

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