Originally posted by wattsr1

'Nuther wun cumming up Rogue06:-

http://www.nature.com/nature/journal...080522-13.html

Looks like another gap to fill in now.


Regards, Roland

Being the "frogamander" is a transitional I put it in the Time for YECs to Reconsider Transitional Fossils? thread

Originally posted by rogue06

Being the "frogamander" is a transitional I put it in the Time for YECs to Reconsider Transitional Fossils? thread

Ahh that's the thread.

When I put it here, there was a thought in the back of my mind that this was the wrong thread.

So thank you.


Regards, Roland

Originally posted by wattsr1

Ahh that's the thread.

When I put it here, there was a thought in the back of my mind that this was the wrong thread.

So thank you.


Regards, Roland

No. Thank you. I didn't mean for the response to sound curt.

Originally posted by rogue06

No. Thank you. I didn't mean for the response to sound curt.

Oh no R06. You did not sound curt at all. I was simply thanking you.

I use up all my bad manners on Jorge and Calminian.


Regards, Roland

Here is another gap filled.

'Frog-amander' Fossil Fills Evolutionary Gap

By Jeanna Bryner, Senior Writer

Originally posted by Dr.GH

Here is another gap filled.

'Frog-amander' Fossil Fills Evolutionary Gap

By Jeanna Bryner, Senior Writer

Here is the letter concerning it in Nature: A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders

The “Carolina Bays,” small bodies of water that are found stretching from North Florida up to New Jersey, are named for the abundance of Bay Trees that are found around them. One of the many folktales surrounding the creation of them is that they were formed by gigantic prehistoric whales that had gotten stranded on the beach and made the depressions as they flopped around trying to get back to the ocean.

The reason that I bring up this old legend is that in the largest of the Bay Lakes in North Carolina, Lake Waccamaw, located 20-some miles west of Wilmington, a fossilized skull of a baleen whale that was probably about 20’ (0.6 meters) long was discovered. Most of it has been recovered, including the section of jaw that Cathy Nelson, who was the one who discovered the fossil, kept stepping on as she walked around in the waist-deep water near her pier. The skull was partially encased in limestone and appears to be relatively intact (rare for whale skulls found in the area), and cautiously optimistic that there are other bones left to be found. And the whale skull may be the largest found in the state, but is still at least a thousand times too small to be from the whales whose flopping about are responsible for creating the lakes.

Further Reading:

Whale of a find in Lake Waccamaw

Digging for prehistoric whale bones on Lake Waccamaw

Shark teeth are one of the most common fossilized animal parts found. This has a lot to do with the fact shark’s are constantly replacing their teeth (which aren’t attached to the jaw but are embedded in the flesh, with multiple rows of them continuously moving forward as if on some sort of conveyor belt), few of which last even a month before being “shed.” I once read that a shark can lose well over 20,000 teeth during its lifetime. And considering that sharks have been around for nearly 400 million years, that makes for a lot of potential candidates for fossilization (which takes about 10,000 years in the ocean).

As the teeth sit on the ocean floor they absorb minerals from the sediment which is what turns them different colors over time. A very general rule of thumb is that the darker the tooth is the older it is. But darkness of color isn’t always a good indicator and tides and currents tend to deposit them willy-nilly, hence accurately identifying the actual age of a shark’s tooth has been far from an exact science. But that may have finally changed.

A team led by Martin Becker, an associate professor of environmental science at William Paterson University, New Jersey, analyzed shark teeth (primarily those identified as having come from Scapanorhynchus texanus, a.k.a., the “goblin shark of Texas” and “spade snout”) and may have come up with a way to accurately date them.

The researchers studied the strontium isotope composition from the three primary parts of the tooth – the roots, the pulp cavity and the enamel surface since there is a radioactive component in the isotopes that, due to decay, slowly increases over time. When this is compared with the part of strontium’s atoms that doesn’t change, an age can be determined. They further discovered that the enamel provided far more precise information than the other parts of the tooth, which means that any analysis conducted in the future probably should primarily concentrate on the hard enamel surfaces of the tooth. IIRC, this concurs with some other recent findings on other very different creatures.

"We expect that enamel in any creature would be less susceptible to alteration after its formation than the other dental tissues, probably because enamel is well-crystallized and not as porous as dentine," explained David Seidemann, a Brooklyn College geochemist and a co-author of the paper, which has been accepted for publication in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

Additionally, this technique appears to be useful in attempting to reconstruct what the environments that the sharks whose teeth are being studied lived in, since the chemical makeup of the teeth typically locks in specific isotopic signatures of the seawater in which the shark lived.

This new dating method was able to determine that the teeth they tested, which came from a near vertical cliff cut by Trussels Creek in Greene County, in western Alabama, were approximately 78.8 to 79.2 myo.

“Judging from the abundance of shark teeth preserved in the Cretaceous of Alabama, sharks were abundant in Alabama seas during the Cretaceous,” Martin Becker said. “Shark teeth are also abundant, however, in Cretaceous deposits of the Gulf Coast and the Atlantic coastal plain, so it's pretty clear that they were abundant up and down the coast of what is now the United States.”


Further Reading:

Sharks Ruled Alabama's Dino-Era Waters

Originally posted by rogue06

Shark teeth are one of the most common fossilized animal parts found. This has a lot to do with the fact shark’s are constantly replacing their teeth (which aren’t attached to the jaw but are embedded in the flesh, with multiple rows of them continuously moving forward as if on some sort of conveyor belt), few of which last even a month before being “shed.” I once read that a shark can lose well over 20,000 teeth during its lifetime. And considering that sharks have been around for nearly 400 million years, that makes for a lot of potential candidates for fossilization (which takes about 10,000 years in the ocean).

Considering the raw number of fossil shark's teeth, And a formation time of 10,000 years - I wonder how a YEC reconciles the YEC timeframe with:

A)formation time of shark tooth fossils
B) raw number of sharks required to make all those teeth (even in a shortened formation time)
C) predation before the fall (I doubt sharks ever ate coconuts - or seaweed).


Jim

Noah (and everyone else) never swam in the ocean. Too dangerous.
Why do you think he had to build such a large boat? Anything smaller would have been swamped by sharks!

New research into the largest variety of flying reptiles known as pterosaurs, that lived back when dinosaurs walked the land between 65 and 230 mya, has found that instead of getting their food by skimming across lakes and seas grabbing fish from the water’s surface much like modern seagulls and pelicans do, they actually were more likely to stalk animals on the ground while on foot. That’s right, at least in the case of the Azhdarchids, which included the largest flying animal ever, Quetzalcoatlus that had wingspans up to 12 meters (39.3’), they probably were a specialized ground based stalking creature.

A team led by Dr. Darren Naish of the School of Earth and Environmental Studies at the University of Portsmouth, England looked at fossils of Azhdarchids from London, Portsmouth and Germany, and found that anatomically speaking they’re markedly different from others animals that skim prey off the water’s surface. Azhdarchids lack every one of thirty specialized adaptations for skimming found in the head and neck of the modern skimming bird Rynchops. Skim-feeders need a flexible neck to dip and absorb the impact of trawling through the water and catching either a fish or shrimp. In contrast the Azhdarchids have long (up to 10’) and unusually rigid necks,
which has led the researchers to question the conventional belief of how the fed.

Some had also proposed that Azhdarchids used their long pointy beaks to probe through soft mud in search of shellfish and maybe some amphibians. But again the anatomy doesn’t match up. These pterosaurs’ jaws might be long enough but were too weak as compared to other sediment probers. Their footprints reveal that they possessed relatively small padded feet which would be completely unsuitable for wading. “If you go wading out into this soft mud, and you weigh a quarter of a ton, and you've got these dinky little feet, you're going to just sink in,” noted the lead author of the paper, Mark Witton. Still the team asserts the giant pterosaurs probably waded at times.

Witton and Naish have concluded that all of these features point toward a ground-living lifestyle in which Azhdarchids walked about and reached down to grab and pick up prey much like large ground-feeding birds like storks and ground-hornbills do today. “In our hypothesis, flight is primarily a locomotive method,” said Witton. “They're just using it to get from point A to point B. We think the majority of their lives, when they're feeding and reproducing, that's all being done on the ground rather than in the air.”

To feed “all a terrestrial stalker needs to do is raise and lower its bill tip to the ground,” remarked Naish. Although most people think of storks as waders, the type that most closely resembled Azhdarchids are the Marabou storks, which are terrestrial stalkers that forage in inland habitats like grasslands. Azhdarchids’ huge beaks and towering height (some as tall as a giraffe) should find plenty to eat. “As for what Azhdarchids would eat, they'd have snapped up bite-size animals or even bits of fruit. But if your skull is over two metres in length then bite-size includes everything up to a dinosaur the size of a fox.”

Further support for this new terrestrial stalker model comes from their fossil distribution and tracks. More than half the known Azhdarchid fossils were recovered from sediments that were laid down inland including the fossilized remains of a Quetzalcoatlus that was unearthed 400km (nearly 250 miles) from the nearest contemporary shoreline. Moreover, the only articulated Azhdarchid fossils we have found originate from these inland sediments.

The team rejected the idea that the inland fossils may be a result of migratory behavior, with the fossils originating from deaths en route primarily because they believe that it is highly unlikely that the vast majority of Azhdarchid fossils became associated with continental deposits through chance deaths of migrating animals.

Aside from the controversy surrounding Azhdarchids morphology and habitat, I think the the team choose these pterosaurs to study partly because they were among the most widespread and successful of the pterosaur clades giving them plenty of material to work with. Still more material will need to be studied, especially more tracks (too few at present) before any conclusions can be thought of as definite. I think that it is important to keep in mind that this study doesn’t claim that all pterosaurs are necessarily terrestrial stalkers. Many of the smaller pterosaurs, especially ones like Pterodaustro, probably grabbed fish from the water in the way modern seabirds do.


Further Reading:

A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology Abstract & Paper

Giant Flying Reptiles Preferred To Walk

Giant pterosaurs stalked baby dinos 'like storks'

Giant flying reptile not much of a flyer

Fossil prints reveal giant winged reptile was a stalker

Dinosaur experts bring the myth of the pterosaur back down to earth

The fossilized remains of a placoderm fish discovered in Australia is creating quite a stir in scientific circles. Placoderms are an extinct type of armored fish that were among the first jawed fish and lived from the early Silurian to the end of the Devonian. While the fish, a Materpiscis attenboroughi (“Attenborough’s mother fish,” named after naturalist Sir David Attenborough) and estimated at being 380 myo, probably represents a new species, much more importantly it contains the oldest evidence of an animal giving live birth – pushing back the date for such reproduction approximately 200 million years.

The 25cm (9.8”) long fossil fish was discovered in the Gogo formation near Fitzroy Crossing, which during the Devonian Period was a 1400km (870 mile) long coral reef off the Kimberley coast of northwest of Australia. It was extraordinarily well preserved in three dimensions and contained an intra-uterine embryo attached to a calcified umbilical cord inside the soon-to-be mother’s body. Previously scientists thought that the life forms that existed during these times had only evolved to reproduce using externally fertilized eggs - a primitive version of the way fish spawn today.

The embryo (which was about a quarter the size of the mother) was discovered by chance when it was given an additional acid bath to expose more of its shoulder from the rock. The researchers concluded that it was an embryo rather than ingested prey because the delicate bones show no breakage or etching from stomach acids. Further examination of the fossil under high-resolution scanning electron microscopy and computer tomography scanning, clearly showed the path of a major blood vessel inside the umbilical cord and possibly the recrystallised yolk sac. It appears to have employed a tail-first birthing process that was probably similar to that of some species of sharks and rays living today.

The discovery of such a complicated reproductive system this far back will most likely change our understanding of the evolution of vertebrates. “It shows us that live birth was occurring at the same time as egg laying, and that these mechanisms evolved together rather than sequentially,” explained Dr. Kate Trinajstic, of the School of Earth and Geographical Sciences at the University of Western Australia, and co-author of the paper being published in the journal Nature on the find. And the large size of the embryo relative to the mother indicates that the young of this fish were born well-formed, a strategy that may have evolved to counter predation.

Further, the discovery of the embryo and umbilical cord within Materpiscis provides the first-ever example of internal fertilization (viviparity) in vertebrates that is, sex with penetration. As Dr. John Long, the head of science at Museum Victoria in Melbourne, Australia and head of the team, remarked: “It dawned on me after studying the specimen that this was the earliest evidence of vertebrates having sex by copulation — not just spawning in water, but sex that was fun.”

The scientists speculate that the embryo-bearing placoderm probably fell victim to rapid depletion of oxygen in the water and settled to the bottom of the sea where they were gently covered in layers of silt-like mud that hardened over time. Trinajstic has mentioned that she has hopes that the fossil might yet yield genetic material and biomolecules.

Also, this find inspired Long and Trinajstic to take an additional look at another fossilized placoderm, an Austroptyctodus gardineri which lived at the same time as Materpiscis and found in 1986, leading them to discover what may be three embryos in that fish’s body that had been previously identified as back scales. This provides strong proof that Materpiscis wasn’t unique among placoderms for giving live birth.



Further Reading:

Fossil captures 380-million-year-old live birth

Oldest Embryo Fossil Found

Australians find a mother of a fossil

World's oldest mother fish found

Fish fossil is oldest to have 'fun sex'

Fossil reveals oldest live birth Includes a short video

A team of Danish scientists have collected DNA from a 3400 to 4500-year-old clump of frozen dark brown human hair discovered in 1988 in the permafrost soil in the Disco Bay region of northwest Greenland that may have solved the mystery of whether or not modern Eskimos descended from ancient Native Americans.

According to a team led by Tom Gilbert of the Center for Ancient Genetics at the University of Copenhagen, Denmark, the first humans to colonize in the Arctic of the New World didn’t descend from Native Americans who originally arrived some 14,000 years ago as had been generally thought, but instead came directly from Asia. Also these first immigrants are not the ancestors to the Inuit who currently populate the area but appear to have died out.

With the mitochondrial DNA sequenced from the hair, Gilbert and his colleagues were able to compare ancient DNA with existing populations from around the Arctic. The closest matches, he says, “came from the Bering Sea region.” Some current residents of the southern Aleutian Islands and the Chutchi Peninsula of Siberia carry similar DNA, he says. So it appears that the person from whom the hair came from was probably from eastern Asia; an ancient Siberian or maybe even from Beringia, the land where the Bering Strait now exists.

Still, as Gilbert acknowledges, this does not conclusively establish that these paleo-Eskimos migrated from the Bering Sea area though it is evidence of a pretty specific geographical link. Since the work was based on a lone hair sample it could conceivably have come from a mercenary who was accompanying the migration rather than from a representative of the actual settler. There are three more hair samples from the same site that hopefully will yield further information.

As an important aside, this sequencing of mitochondrial DNA from a male Paleo-Eskimo who lived roughly 4000 years ago represents the first near-complete ancient mtDNA genome ever published.



Further Reading:

Paleo-Eskimo mtDNA Genome Reveals Matrilineal Discontinuity in Greenland Abstract

Unexpected origin of an early Eskimo

Prehistoric Hair Suggests 1st Eskimos Came From Asia

Ancient hair suggests multiple migrations into Americas

Ancient Hair Reveals Greenland Eskimos' Roots

While giving a tour of the area where “Leonardo,” a fossilized mummy of a hadrosaur or “duckbilled” dinosaur was discovered in 2000, the public-relations coordinator for the Houston Museum of Natural Science, Steven Cowan, made a discovery of his own. The tour of the Malta, Montana (nearly 200 miles north of the state’s capital, Billings and about 20 miles south of the Canadian border) site was part of the preparations surrounding plans to display “Leonardo” at the Houston museum.

Cowan had spotted some bones poking out of a rocky outcropping on a hillside and went to get Mark Thompson, an Australian paleontologist along on the tour. It was late and the weather was bad… “I really didn't want to walk half a mile back to see it, but I did,” said Thompson. “And I saw some tendons, vertebrae, ribs and a shoulder blade. It's a young Brachylophosaurus. It didn't appear to be articulated (with bones connected together), but it may be complete.” “Marco,” the nickname Cowan gave the dinosaur, is the same type of duckbill that “Leonardo” is, and has been dated at about 75 myo.

While not a groundbreaking discovery, what makes this an interesting find is the circumstances surrounding it. As Bob Bakker, the famous and colorful paleontologist and current curator of paleontology at the Houston Museum, noted, it is unlikely that he or other trained paleontologists would have located “Marco.” “One of the things we always need to watch out for is thinking that we know it all,” Bakker said. “I knew enough never to go to a ridge top because you don't find specimens there. But I forgot to tell that to Steven, so he did exactly that and proved me wrong.” Gotta love it



Further Reading:

Museum PR coordinator finds new dinosaur fossil

A novice makes a big dinosaur discovery in Montana

Bob Bakker, as in the paleontologist/Pentecostal preacher?

Originally posted by rogue06

“One of the things we always need to watch out for is thinking that we know it all,” Bakker said. “I knew enough never to go to a ridge top because you don't find specimens there. But I forgot to tell that to Steven, so he did exactly that and proved me wrong.” Gotta love it

I don't know about that. I know a nice spot for dinosaur eggs that is up on a ridge.