An artist's conception shows a pair of Alamosaurus sanjuanensis dinosaurs.
By Alan Boyle, Science Editor, NBC News
Here's a trivia question for your dino-crazy kids: What's the biggest dinosaur to roam North America? Paleontologists report that it's Alamosaurus sanjuanensis, one of many breeds of long-necked, long-tailed sauropods to roam the continent 69 million years ago.
Montana State University's Denver Fowler and the State Museum of Pennsylvania's Robert Sullivan make that judgment on the basis of two huge vertebrae and a femur that they collected in New Mexico between 2003 and 2006. Based on the bones' proportions, they figure that Alamosaurus could be around the same size as South America's giant sauropods, such as the 70-ton Argentinosaurus.
If Fowler and Sullivan are correct, that'd make Alamosaurus twice as heavy as paleontologists thought it was just a few years ago. Their research was published Tuesday in Acta Palaeontologica Polonica.
"Over the past 20 years, Argentinean and Brazilian paleontologists have been unearthing bigger and bigger dinosaurs, putting the rest of the world in the shade," Fowler said in an MSU news release issued Tuesday. "However, our new finds not only show that Alamosaurus is newly recognized as the biggest dinosaur from North America, but also that it was right up there with the biggest South American species: The U.S. is back in the fight for the No.1 spot."
There's more at stake here than mere bragging rights. "Our findings show that Alamosaurus was originally described based on immature material, and this is a problem, as characteristics that define a species are typically only fully gained at adult size," said Fowler, a doctoral student at MSU's Museum of the Rockies. "This means that we might be misinterpreting the relationships of Alamosaurus and possibly other sauropod dinosaurs too."
Researchers from MSU and the Pennsylvania museum are continuing to collect Alamosaurus bones to resolve the size question as well as other details about the dinosaurs' life and death. To keep up with the research — and perhaps eventually find out whether Alamosaurus pushes aside Argentinosaurus and its Russian rival, Ruyangosaurus, check in with the Facebook page for the Horner Paleo Lab at the Museum of the Rockies. You can also check out this video about the Alamosaurus quest:
Never-before-seen dinosaur fossils will go on exhibit when a new science museum opens in Dallas in 2013. KXAS-TV's Julie Tam reports.
When viewers tune in to Fox's "Terra Nova" time-travel TV series, premiering tonight on Fox, they'll see an 85 million-year-old world that's pretty much "terra incognita" for dinosaur experts. And that's just fine with world-famous paleontologist Jack Horner.
"I suggested 85 million, because it's a time that we know the least about, and it's kind of in the middle of the Cretaceous period, which means we could bring some older dinosaurs forward and take some younger dinosaurs back without getting in too much trouble," Horner told me.
So even though the long-necked, plant-eating dinosaur known as Brachiosaurus died out long before Tyrannosaurus rex came onto the scene, their cousins can mix it up in the computer-generated landscape created for "Terra Nova."
"We just cannot use a T. rex, but there are tyrannosaurs, so we can certainly create an animal that looks very similar to T. rex," Horner said.
Tonight's premiere raises the curtain on a series that some critics have characterized as a cross between "The Lost World" and "Lost," with a flashy "Stargate" time portal and an extra dash of "Swiss Family Robinson" thrown in. There are family dramas, shadowy conspiracies and seemingly indecipherable rock markings to stir the pot, but the success of the mega-expensive series arguably depends on the dinosaurs — just as it did for the "Jurassic Park" movie series.
Horner is familiar with the terrain — not only because of his roles as curator of paleontology at Montana's Museum of the Rockies, professor at Montana State University and one of the world's foremost fossil-hunters, but also because he was a consultant for "Jurassic Park" and a model for the movie's alpha-scientist character.
Steven Spielberg, co-executive producer for "Terra Nova," was the one who brought in Horner as a consultant for the "Jurassic Park" movies. "I guess he liked what I did there, so [the TV show's producers] called and asked if I could do it" for "Terra Nova" as well, Horner recalled.
Horner works with the artists and the writers on the dino concepts. "My job really is to make sure the dinosaurs are as accurate as they can be, even if we invent them," he said. "If they're going to be raptorlike dinosaurs, they have to have the characteristics of a raptorial dinosaur ... but when it comes to headgear, we can do a lot of things."
Slasher movie That last comment relates to the first dinosaur invented for the series: a nasty critter referred to as the "Acceraptor" and nicknamed the "Slasher."
"He's got some characteristics that are new, but still within the realm of possibility," Horner said. "The only detail I can tell you is, it's going to be a scary dinosaur. Let's put it this way: I wouldn't want to be in the forest with a Slasher, especially at night."
Further details have seeped out through the dinosaur blogs: The Slasher sports some gaudy headgear that Brian Switek, who blogs about paleontology for Smithsonian magazine and Wired, has criticized as a "horribly lame" look (see below for more). It has some fearsome-looking claws, but its deadliest weapons are the sharp barbs that whip around at the end of its yards-long tail. "As far as I know, that's totally made up," Bob Strauss, who manages About.com's guide to dinosaurs, told me.
Horner said he's willing to give the writers and artists wide latitude when it comes to dreaming up dinosaurs. "If we know something for sure, then we'll keep it within the bounds of science," but if there are blank spaces in the scientific picture, a little (or a lot of) imagination is allowed. This is Hollywood, after all.
"Just like the people in the movie, the dinosaurs are actors. They will go faster than we think dinosaurs can go," Horner admitted.
Food for thought for dino fans That was the case for "Jurassic Park," and Horner is hoping that "Terra Nova" will offer even greater dramatic possibilities, for the dinosaurs as well as for the human actors.
"It's one thing to make a movie. Movies are two hours of a single story," Horner said. "The really cool thing about 'Terra Nova' is that it is a series, so we have the capability of building and building and building on it, each time seeing new animal and plant characters and still being able to follow the family that the story is about. In many ways, it's a lot better than a movie, just on a smaller screen."
And if dinosaur fans want to argue over the finer points of the dinosaur depictions, that's just fine with Horner, too. "If people are watching and paying attention like that, that would be great," he told me.
Here are some of the reviews from experts who are paying attention:
The main reason why the "Terra Nova" colonists go through a rupture in space-time is because the world has become an environmental wasteland by the year 2149. People have to wear "re-breathers" on their faces to cope with the polluted air. But Holtz noted that the world of 85 million B.C. wasn't exactly a breath of fresh air, either.
"If you're trying to escape climate change by going back to the past, you wouldn't want to go back to 85 million years ago, where CO2 is almost 1,000 parts per million, as opposed to 392 at present," he observed. Holtz acknowledged, however, that an elevated carbon dioxide level isn't the only environmental problem facing the smoggy, run-down world of 2149.
As for the dinosaurs, Holtz had a couple of pieces of advice for the writers. First, don't get too specific about the dinosaur names. Instead of referring to Brachiosaurus (the long-necked plant-eater that makes an early appearance on tonight's show) or Carnotaurus (the toothy, horned dinosaur that almost runs down Terra Nova's patriarch in the episode), use more generic names (brachiosaurs or abelisaurs, respectively). There's no evidence that either Brachiosaurus or Carnotaurus was around 85 million years ago, but it's plausible to claim that their distant cousins were.
"Saying it more generically is safer," Holtz said.
Also, as the series goes on, Holtz hopes the writers get the locale right. For example, no Carnotaurus fossils have been found in North America, so if the series claims that the "Terra Nova" colonists are settling in Cretaceous Chicago, coming upon Carnotaurus' older cousins there would be "as unlikely as encountering a koala in Montana," Holtz said.
Most of the TV audience might not care that much about the terminology, but it's better to have the dino-geeks for you than against you. "They get mad enough with the dinosaur documentaries," said Holtz, speaking from experience.
"All I have seen of the 'slasher' is the promotional artwork, but, yes, I'm sorry to say that the creature design for the dinosaur is horribly lame. The poor creature looks as if the special effects artists took one of the Jurassic Park raptors, stuck a crest from an oviraptorid dinosaur on its head, and then gave it a bad toupee. So many fantastic and terrifying dinosaurs have been found — dromaeosaurs with double sickle-claws (Balaur), Allosaurus-cousins with sail backs (Concavenator), crocodile-snouted hunters (Baryonyx), and others — that the I think the show's creators would have done better to draw inspiration from actual dinosaurs rather than trying to dress up a Deinonychus.
"Then there's the scientific issue. Thanks to multiple discoveries of feathered dinosaurs during the past 15 years, we know beyond a shadow of a doubt that many coelurosaurs — the group to which raptors, tyrannosaurs, oviraptorids and others belong — were at least partly covered in feathers. Even Velociraptor arm bones have been found with quill knobs for the attachment of feathers! (The significance of this is that we can now detect the presence of feathers on some dinosaurs even if the feathers themselves are not preserved.) Therefore, the 'slasher' should be a feathery beast and look less like a dinosaur with a comb-over. Every year more feathered coelurosaurs are found, and it's time that television shows and movies featuring these dinosaurs restore the animals with their full plumage. ...
"It is true that our knowledge of dinosaur life around 85 million years ago (the beginning of the Santonian age) is relatively limited. Compared to what we know about the later Campanian (83 million to 70 million years ago) and Maastrichtian (70 million to 65 million years ago) ages, the world of dinosaurs during the Santonian is still fuzzy and waiting to be fleshed out by new discoveries. That said, I don't have a problem with a show creating new dinosaurs or even bringing in dinosaurs from slightly older or younger time periods. (If I recall correctly, Carnotaurus — a Campanian dinosaur from prehistoric Argentina — is in the show.) Sometimes scientific accuracy needs to be bent a little to make compelling television. That's just the way it goes when you want to tell a story.
"Nevertheless, I don't think any imaginary dinosaur can really compare to the real animals we're finding. Spielberg and the show's co-creators can dream up as many dinosaurs as they want, but, to me, speculative creatures like the slasher are always going to pale in comparison to the bizarre array of wonderful dinosaurs paleontologists have uncovered."
Strauss said "Jurassic Park" stirred up a lot of controversy on the subject of dinosaur verisimilitude. For example, real Velociraptors were nowhere near smart enough or agile enough to turn a doorknob, and pterosaurs weren't strong enough to carry off a kid.
"Terra Nova" could well do the same, and not just because of slasher's barb-whipping tail. Did brachiosaurs really eat small lizards, or were they strictly herbivores? Shouldn't the TV series' Carnotaurus have arms as wimpy as the real thing? Where's the slasher's hind-foot claw?
But judging by the first show, Strauss thinks dino-geeks will stick with the series, if for no other reason than to get their weekly Cretaceous fix and debate how the Hollywood monsters compare with the real things. "They're just so happy to have dinosaurs on TV," he told me.
An artist's conception shows how the birdlike dinosaur known as Xiaotingia zhengi might have looked.
By Alan Boyle, Science Editor, NBC News
The newfound fossil of a 155 million-year-old feathered dinosaur has led scientists to claim that Archaeopteryx, the species long held forth as the "oldest bird," is no bird at all.
Chinese researchers made the claim in Thursday's issue of the journal Nature, and an outside expert says the study "is likely to rock the paleontological community for years to come." Ohio University paleontologist Lawrence Witmer noted that the latest research, focusing on a fossil species dubbed Xiaotingia zhengi, comes 150 years after the discovery of Archaeopteryx, which marked a milestone in the study of the origin of birds.
"It's fitting that 150 years later, Archaeopteryx is right back at center stage," Witmer told me.
Xiaotingia was found by a collector in China's Liaoning Province, a hotbed for feathered-dino fossils, and sold to the Shandong Tianyu Museum of Nature. Paleontologists led by Xing Xu of the Chinese Academy of Sciences analyzed the fossil's skeletal measurements in detail and fed them into a computer database with measurements from 89 fossilized dinosaur and bird species, including Archaeopteryx.
Without Xiaotingia, the computer analysis put Archaeopteryx on the evolutionary line leading to modern-day birds. But when Xiaotingia was included, Archaeopteryx was placed in a group of birdlike dinosaurs known as deinonychosaurs. The differences had to do with details such as the shape of the wishbone and the skull's snout.
Archaeopteryx was about the size of a modern-day crow, and Xiaotingia was as big as a chicken.
Xu et al., Nature
The fossil skeleton of Xiaotingia zhengi is splayed out in rock.
"If you just looked at Xiaotingia, you'd say, 'Oh, boy, another little feathered dinosaur from China,'" Thomas Holtz, a paleontologist at the University of Maryland at College Park who reviewed the study for Nature, told me. "In and of itself, it is not a particularly unusual animal. But the combination of traits, at least in their analysis, pulls Archaeopteryx over to the deinonychosaur side of things."
The researchers acknowledged that their reclassification was "only weakly supported by the available data," but they said this kind of fuzziness was to be expected when the fossils being analyzed are close to the common ancestor of now-extinct dinosaurs and modern birds. "This phenomenon is also seen in some other major transitions, including the origins of major mammalian groups," they wrote.
Witmer agreed: "We're looking at an origin, and consequently it's going to be messy."
The 150 million-year-old Archaeopteryx fossil, which was discovered in southern Germany in 1861, was long seen as the oldest evidence of a bird species because the rocky imprint bore traces of feathers. But over the past decade or two, many dinosaur fossils have been found with evidence of feathers — to the extent that some scientists have been able to figure out how the feathers were colored. As a result, some researchers have argued for years that Archaeopteryx should be reclassified.
In the past, creationists have used Archaeopteryx in their arguments against evolutionary theory, contending that birds always existed in their feathered form and did not evolve from dinosaurs. Evolution's critics may try to spin these latest findings to their advantage as well, Witmer said.
"It may well be they're going to suggest that we evolutionists don't know what we're doing," he told me. "In reality, it's just the opposite. It just shows what evolution is all about. A prediction of evolutionary theory is that it should be really hard for us to figure out what's going on in an origin."
Archaeopteryx's dethronement means the title of "oldest bird" could fall to other ancient species, such as Epidexipteryx hui, Jeholornis and Sapeornis, Witmer said. "They're not exactly household names," he noted. "These new characters have been known only for 10 years or less." Archaeopteryx, meanwhile, would be lumped in with Xiaotingia as well as another feathered-dino species called Anchiornis huxleyi.
G. Mayr / Senckenberg
An Archaeopteryx specimen highlights wing and tail feather impressions.
The renewed debate over Archaeopteryx's classification is far from finished. Holtze said he knew some researchers who were inclined to go with a completely different classification scheme, which would put the deinonychosaurs along with Archaeopteryx on the evolutionary line leading to modern-day birds.
The debate could also require a rethinking of how birds arose, and how features such as feathers and flight developed. Holtz said some paleontologists have suggested that Archaeopteryx was not a particularly good flier, and putting it in the deinonychosaur category would make more sense on that score. It may turn out that deinonychosaurs gradually evolved from so-so fliers into feathered but flightless animals. "They would have been nasty predatory analogs to ostriches," Holtz said.
Holtz acknowledged that Archaeopteryx "has been our image of what early birds are like, for the historical reason that it's been known for 150 years as having all these feathers." The fact that the fossil was found just two years after Charles Darwin published "On the Origin of Species" added to its image as an evolutionary icon. A dramatic change in that image might come as another scientific shock to folks who are already being told that there's no such thing as a brontosaur, and that Pluto no longer ranks among the solar system's major planets.
"To which I say, 'Get over it!'" Holtz said. "Science is about changing ideas based on evidence, not about ignoring evidence to conform to our comfortable ideas."
An artist's conception shows a typical sauropod with a long neck, long tail and massive body.
By Alan Boyle, Science Editor, NBC News
How warm was a dinosaur's blood? Researchers report that it was about as warm as ours, based on a chemical analysis of sauropod teeth, of all things. The novel findings, published today by the journal Science, are consistent with the view that at least some dinosaur species were warm-blooded — and suggest a way to settle the controversy conclusively.
"What we're basically doing is sticking a thermometer up a dinosaur's butt," study co-author John Eiler, a geochemist at Caltech, told me jokingly.
What the researchers actually did was to drill out samples of fossilized tooth enamel from an assortment of sauropods, the largest kind of dinosaurs. Then they analyzed how different isotopes of carbon and oxygen were bonded together in apatite, a rare form of carbonate found in the enamel.
Past experiments have shown that the heavier isotopes — carbon-13 and oxygen-18 — are more likely to clump together when the carbonates are formed at lower temperatures. At higher temperatures, the bonds are more randomly distributed, and you don't see as many of the heavy isotopes clumping together. The precise proportion of the clumped isotopes can tell you the average body temperature of a toothy organism.
"This is the basis of the 'thermometer,' but it's a thermometer where all the information that allows you to rigorously calculate temperature is preserved in a single phase," Eiler said.
He said clumped-isotope thermometry has been tested with teeth from sharks, birds, crocodiles, rhinos and elephants, "and it just works for all of them." The procedure was also tried on a woolly mammoth's 20,000-year-old teeth and the 12 million-year-old teeth of an ancient crocodile and rhino. But this is the first time results have been reported from 150 million-year-old dinosaur teeth.
The analysis was done on 11 teeth from Brachiosaurus and Camarasaurus dinosaurs from Tanzania, Oklahoma and Utah. Other samples were judged unsuitable for the sensitive chemical tests. "Did we do it perfectly?" Eiler said. "We believe that we found a result that we're confident in, but it's not easy."
Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum of Los Angeles County, told me in an email that the findings were "quite interesting and promising."
Warm blood ... but warm-blooded? It turns out that the temperature Eiler and his colleagues came up with — 36 to 38 degrees Celsius, or 97 to 100 degrees Fahrenheit — is consistent with previous estimates produced by other methods. But Eiler said those methods, including one that involves comparing the different oxygen isotopes in dinosaur teeth, resulted in less direct measurements.
"None of those are simple applications of a thermometer," he said. "They all require some kind of assumption about the nature of the body fluid that the structure grew from."
The key point behind the research isn't necessarily that dinosaurs had blood as warm as ours. "The deeper question is, how did they get that way?" Eiler said. "What allowed them to get to that temperature? Was it through regulation of their metabolism, like it is for us? Was it simply their size? This is the next step."
Some scientists hold to the view that dinosaurs as a group might not have been strictly warm-blooded (like today's birds and mammals) or cold-blooded (like most reptiles). They suggest that some dinosaurs were big enough to keep their blood warm due to thermal inertia — as alligators and Galapagos tortoises do.
Eiler said the newly published temperature estimates are not consistent with that hypothesis. "They're not as hot as they were supposed to be," he said, "and that tells us there's something about dinosaur physiology that we don't understand."
To get at the answer, the scientists want to take lots more temperature readings, using the tooth enamel from big and little dinosaurs: from juvenile sauropods and dwarf sauropods, as well as from another class of dinosaurs known as theropods, which include Tyrannosaurus rex and are thought to be more closely related to birds.
"If sauropods were like mammals, you would expect the small animals to have the same body temperature as the large ones," Caltech biologist Robert Eagle, the Science study's lead author, told me. But if the temperature readings vary significantly, that would tip the scales back toward the thermal-inertia hypothesis — or it might force scientists to come up with a whole new hypothesis.
Caltech's John Eiler and Robert Eagle discuss the chemical "thermometer."
Beyond dinosaurs And that's just the start. "When you start to think about the evolutionary transition between dinosaurs and birds, maybe you can interrogate these evolutionary transitions and find out when warm-bloodedness arrived," Eagle said. "We have no idea when that happened."
If it turns out that dinosaurs were truly warm-blooded, scientists could work their way backward toward the common ancestor of dinosaurs and crocodiles, to study how body temperature regulation might have evolved during the Permian geologic period, more than 250 million years ago. "The only limitation is whether there's enough well-preserved fossil material," Eagle said. "That doesn't necessarily depend on age. ... It's definitely theoretically possible that we can go all the way back to the Permian."
Eagle said the clumped-isotope thermometer has already been used on rocks and the shells of marine organisms to study ancient climate change, and now it's being applied to a meteorite from Mars as well. In that experiment, researchers want to find out "whether this meteorite experienced high temperatures on the journey from Mars to Earth," he said. If there's no evidence of high temperatures, that might support claims that organisms could make their way between the planets inside such meteorites — an idea that set off a storm of controversy earlier this year.
Eiler said we'll probably be hearing much more about this temperature-taking technique in the years to come: "It's still recent enough and exotic enough that you wouldn't quite want to call it mature, but it's established. ... Applying it to teeth, I think our lab remains unique in doing that, although I'm sure other labs will be doing it soon."
Update for 11:45 p.m. ET: I followed up with a phone call to Luis Chiappe, the dinosaur expert at the L.A. museum, and he said there may well be other applications for this technique. "I would imagine that the way it happens is, people realize there's a new tool on the table and they will grab it and use it in various ways." For example, Chiappe is an expert on dinosaur eggs, and it's not unthinkable that you could measure egg temperatures to investigate how dinosaur moms hatched their young. Modern-day crocodiles use temperature to determine the sex of their hatchings. Did dinos do the same?
Chiappe agrees that the next task is to test other sizes of dinosaurs.
"If we were to find comparable temperatures in hatchlings of sauropods and juveniles of sauropods, that would definitely support the idea that these animals were endotherms [warm-blooded]. So that needs to be done," he said. "The problem is that the technique is a destructive technique. Therefore, not too many museum curators will be happy to donate their specimens to be destroyed."
"Dinosaur Body Temperatures Determined from Isotopic (C13-O18) Ordering in Fossil Biominerals" was published today on the journal Science's website and will appear in a future issue of the print version. In addition to Eagle and Eiler, the authors include Thomas Tütken, Taylor S. Martin, Aradhna K. Tripati, Henry C. Fricke, Melissa Connely and Richard L. Cifelli.
An artist's conception shows the sail-backed creature known as Xilousuchus sapingensis, which existed 247 million to 252 million years ago. A new analysis of fossilized Xilousuchus bones suggests that crocodiles diverged from birds and dinosaurs earlier than some experts previously thought
By Alan Boyle, Science Editor, NBC News
A fresh analysis of a fossil found in the 1970s suggests that the family trees for crocodiles, birds and dinosaurs diverged earlier than some may have thought.
The study represents the latest chapter in a long-running debate over the relationships between dinosaurs and the ancestors of two dissimilar types of modern-day creatures — crocs and birds.
Paleontologists have traced the ancestry of all three groups to a category of common ancestors called archosaurs. The archosaurs and their cousins lived around the time of Earth's deadliest die-off, the Permian-Triassic extinction, around 252 million years ago. Teasing out the details of the archosaurs' family tree is key to understanding how birds, dinosaurs and crocodiles are linked.
"This is one of the most interesting evolutionary questions in paleontology: the origin of birds in the broadest sense," Spencer G. Lucas, curator of paleontology at the New Mexico Museum of Natural History, told me today. "If you take crocodiles, birds and dinosaurs, how do you think that evolutionary tree came together?"
Second look at fossils from China The new analysis, published on Tuesday in Earth and Environmental Science Transactions of the Royal Society of Edinburgh, focuses on the fossilized remains of a creature unearthed in China, known as Xilousuchus sapingensis. The specimen, consisting of a partial skull and 10 neck vertebrae, has been dated to the Early Triassic (252 million to 247 million years ago).
Xilousuchus was originally classified as a distant offshoot of the archosaur tree, known as Proterosuchia, and was thus thought to shed little light on the bird-croc-dino relationship. But the revised analysis puts it closer to the center of the archosaur family tree, and tending toward the crocodile side of an evolutionary split. Birds and dinosaurs would be on the other side of that split, said Sterling Nesbitt, a postdoctoral researcher at the University of Washington who led the research team.
The technique that was used for the analysis involved making detailed measurements of features in the fossilized bones. For example, if a fossilized specimen shows the hallmarks of a wing, that could lead scientists to classify the fossil as belonging to a bird.
"We used the same kind of reasoning for all the little features on the bones where the muscles attach, and we score it into this computer program and it tells us how these creatures are related," Nesbitt explained. "Once you put it into this context, it all falls together. ... Xilousuchus is our oldest evidence of an archosaur in the fossil record."
What it all means ... or maybe not The fact that the main group of archosaurs showed signs of divergence so soon after the Permian-Triassic extinction suggested to Nesbitt and his colleagues that there might be a linkage. "It could have been that the Permian extinction triggered the rise of archosaurs because they filled a niche that was emptied by the extinction," he told me. "This is one possibility that we're looking into now."
Just as the demise of the dinosaurs led to the rise of mammals 65 million years ago, the earlier mass extinction may have contributed to the rise of the dinosaurs 250 million years ago, Nesbitt said.
At the New Mexico museum, Lucas said he wasn't sure the case was that clear-cut. There are so few specimens from the Permian-Triassic transition that the criteria for classification are still subject to debate, and it would be easy to make too much out of the fine distinctions between one fossil and another. "Some of this is merely semantics," he said.
"This is an interesting idea," he told me, "but I await the next analysis of the evolutionary relationship. All of this is really in flux."
Update for 10 p.m. ET: I heard back via email from Thomas Holtz, a paleontologist at the University of Maryland and author of "Dinosaurs," a dino-encyclopedia. Here's what he had to say:
"Although I haven't read the paper yet, the conclusions seem sound. That is, Nesbitt and his colleagues have closely re-examined a lot of the Triassic archosaurs and other archosauriforms (what we used to call 'thecodonts' in the old days, until it was recognized that 'thecodonts' just meant 'any poor archosauriform unlucky enough not to be a crocodilian, pterosaur, or dinosaur'), and have the biggest phylogenetic analyses of these guys out there.
"Xilosuchus falls out as a member of the poposauroids in their studies, an odd assemblage of croc-relatives (some look a lot like finned proto-mammals like Dimetrodon; others look superficially like dinosaurs).
"Because it is a poposauroid, that means that the common ancestor of all poposauroids, and of all pseudosuchians (all archosaurs closer to crocodilians than to birds) must have already been present. And if Pseudosuchia is present, its sister group Avemetatarsalia (birds and everything closer to birds) has to be present in at least its most primitive state.
"Now the avemetatarsalians at this time wouldn't be birds, or theropods, or even dinosaurs. In fact, Avemetatarsalia probably had not yet split into Pterosauromorpha and Dinosauromorpha. But it does mean that the lineages which would ultimate lead to alligators on one side and eagles on the other had already diverged in the earliest days of the Triassic."
Correction for 11:40 a.m. ET May 19: I scrambled up the comparison of crocodiles to dinosaurs in the original text, but have fixed that. Sorry about the mix-up.
The skull of a Tyrannosaurus rex may have brought in more money ... $215,000, to be precise. But the items that attracted the most attention today at I.M. Chait Gallery/Auctioneers' annual natural history auction in New York were of humbler origin: lumps of fossilized dinosaur poop, also known as coprolites, which sold for $1,200. Coprolites are nothing like your garden-variety droppings. Scientists find them interesting because their composition can hint at the diets of prehistoric creatures (including humans), while collectors find them interesting partly because of the "eww" factor. (Last year, a Swiss watchmaker unveiled a $11,290 timepiece made from coprolite.) Watch this video from msnbc.com's Todd Kenreck for more about coprolite commerce.
An illustration by Brazilian paleontologist Juan Carlos Cisneros depicts the mammal-like creature known as Tiarajudens eccentricus displaying its teeth to scare off a carnivorous dinocephalian.
By Alan Boyle, Science Editor, NBC News
Back in 260 million B.C., the mammal-like creature known as Tiarajudens eccentricus looked as fearsome as any predator —possessing rows of teeth that went all the way back into its palate, with two saber teeth sticking out in the front. But paleontologists say this dog-sized monster lived on a strictly vegetarian diet. So why did it have all those menacing choppers?
In this week's issue of the journal Science, researchers from Brazil and South Africa examine the strange case of Tiarajudens, a newly identified type of distant mammalian relative known as a therapsid, and they go on to suggest possible solutions to the dental dilemma.
First, about those saber teeth: Although they weren't used for spearing prey, they could have been brandished to keep predators away. Or perhaps the teeth helped chop up the Paleozoic salad fixings before Tiarajudens chewed it up.
A reconstruction shows the head of Tiarajudens eccentricus.
Another possibility is that the teeth were actually used by one male against another in the competition for mates. The researchers noted that musk deer use their own saber teeth for just that purpose. Other types of Paleozoic animals, such as dinocephalians, apparently butted heads to fight over mates. Tiarajudens' teeth may have enabled an alternate form of ritualized combat.
"Some other Paleozoic animals also had enlarged canines, but they were all carnivores. This is the first case of a saber-toothed herbivore at that time," research team leader Juan Carlos Cisneros, a paleontologist at Brazil's Federal University of Piaui, told me in an email. "Other herbivores with long canines appeared much later in the Cenozoic, including fossil deer. ... Some researchers have proposed that these fossil deer (which did not possess antlers) used their canines for male-male combat, like modern saber-toothed deer do."
Cisneros said he and his colleagues from the Federal University of Rio Grande do Sul found the Tiarajudens skull in March 2009 during a field campaign in southern Brazil. During the two years that followed, the research team cleaned the fossilized pieces, glued them together and analyzed how they were put together. The creature's name comes from "Tiaraju," the place in Brazil where the fossil was found; "dens," the Latin word for teeth; and "eccentricus" ... well, you can figure that one out yourself.
In addition to the saber teeth, the bunches of teeth in the palate make Tiarajudens eccentricus "extremely unusual," Cisneros told me.
"I would compare it with modern mammals, which have one row of enlarged teeth for mastication — except that no mammal has teeth in the palate, but the animal is so bizarre that no comparison is perfect!" he said.
Why so many teeth? "Tiarajudens, as far as we know, was the earliest therapsid capable of actual chewing," Cisneros said. "Its teeth are an answer to make possible the digestion of abundant but poorly nutritious food (fiber plants)."
Those molars in the palate provided extra chewing power, plus replacements as the teeth wore down.
Present-day ruminants, such as cows and sheep, also have to do a lot of chewing to digest their similarly high-cellulose fare. In fact, they've developed a complex set of stomach compartments to break down their food for multiple chewings. There's no sign that Tiarajudens had a similar digestive system, however.
Did Tiarajudens pass down any of its dazzling dentition to present-day species? Almost certainly not. "They are dead ends," Cisneros said. But the saber teeth and long rows of molars show how some of the same solutions arise over and over again in the course of evolution.
A fossil from southern Brazil shows the skull of Tiarajudens eccentricus, including the remains of its saber teeth and palatal teeth.
"Both the saber teeth and the enlarged molar-like teeth in the palate represent convergence with other similar animals," Cisneros said. "These traits appeared and disappeared many times in therapsids."
The discovery by Cisneros and his colleagues "provides novel insights into early tooth differentiation" among therapsids, as well as the evolution of plant-eating "and its accompanying complex social interactions," Jörg Fröbisch, a paleontologist at the Humboldt Museum in Berlin, wrote in a Science commentary.
Therapsids have often been called "mammal-like reptiles," but Fröbisch told me that term isn't quite correct. "These animals are more closely related to mammals than to reptiles," he said. So maybe we have more in common with the toothsome Tiarajudens than we might think.
In addition to Cisneros, the authors of "Dental Occlusion in a 260-Million-Year-Old Therapsid With Saber Canines From the Permian of Brazil" include Fernando Abdala, Bruce S. Rubidge, Paula Camboim Dentzien-Dias and Ana de Oliveira Bueno.
The long-extinct woolly mammoth could be resurrected within five years, thanks to recent advances in cloning technology.
Japanese researchers plan to collect mammoth tissue this summer from a carcass that was frozen in the Siberian permafrost and is now in a Russian research laboratory, according to a report in the Yomiuri Shimbun.
The hope is to recover an undamaged nucleus of a mammoth cell from this tissue and insert it into an elephant egg cell from which the nucleus has been removed. This will create an embryo with mammoth genes, according to the news report.
This embryo will be inserted to the elephant's womb in hopes that she'll give birth to a mammoth.
"Preparations to realize this goal have been made," Akira Iritani, a team leader from Kyoto University, told the Yomiuri Shimbun.
New technique Previous attempts to recover nuclei from frozen tissue failed because the cold temperatures damaged the DNA.
Iritani says his team has devised a method to extract the nuclei of mammoth cells without damaging them. "Now that the technical problems have been overcome, all we need is a good sample of soft tissue from a frozen mammoth," he told London's Daily Telegraph.
Mammoth for display If the team is successful in creating an embryo, they will discuss how to breed the mammoth — and whether or not to display it to the public — before transplanting to a surrogate elephant, Iritani told the Yomiuri Shimbun.
Even if the embryo is successfully created and implanted, the chances of bringing a cloned mammoth to term (or any cloned animal, for that matter) are slim. When South Korean researchers tried cloning dogs, for example, nearly 1,100 embryos were transplanted to surrogate dogs, but only two live births resulted, and only one of those puppies survived past the 22-day mark.
Nevertheless, Iritani was confident of success. "After the mammoth is born, we'll examine its ecology and genes to study why the species became extinct and other factors," he said.
Woolly mammoths went extinct at the end of the Ice Age, about 10,000 years ago. Scientists have long debated whether climate change or human hunters were the cause of their demise.
Last December, researchers said another factor could be the fact that the creatures delayed weaning their young due to the long dark winter north of the Arctic Circle.
How do you turn a bunch of bones into a gorgeous picture of a Gorgosaurus? In a newly published book, two paleontologists and an artist from Australia describe the process that's worked for them for more than 30 years.
The Monash Science Center's Patricia Vickers-Rich and her husband, Museum Victoria's Thomas Rich, write about the paleontological groundwork that they do to figure out how extinct species looked — and how they lived. Freelance artist Peter Trusler, who was trained in zoology at Monash University, writes about how he builds on that groundwork to flesh out his pictures of those species. But it's clear that their method is not just a one-way assembly line leading from the fossils to the finished product.
"Sometimes the horse leads the cart, and sometimes the cart leads the horse," Trusler told me.
The way Trusler sees it, his illustrations are often "another one of the investigative tools in science to try to increase our understanding." And the Riches appreciate what he does.
"Peter is not only an artist," Thomas Rich told me. "He's also a very well-qualified scientist. He could have easily gone down that academic route, so you're not talking about a person who just draws pretty pictures."
Patricia Vickers-Rich agreed: "He's basically a scientist, too. He just happens to be a scientist who has a good style of art. ... We've got a very special guy there."
Trusler, who will be going for his Ph.D. under Vickers-Rich's guidance, goes out on expeditions just like the other scientists. "In some cases, I've sent Peter in the field in place of me," Vickers-Rich said. "If there was not a lot of money, I would send him."
Tom Rich recalled the time Trusler went out and gathered up some ginkgo leaves, then cut incisions into the leaves to get an idea of what the ancient Ginkgoides australis species looked like. Trusler often asks questions about how a particular anatomical feature might have worked, or how a creature's surroundings might have looked in ancient times. "If we couldn't provide the answers, he would go out and find a way to supply the answers," Rich said.
It's not cheap to document the discoveries made by paleontologists, Vickers-Rich pointed out. Supporting the effort requires major-league fundraising.
"It doesn't just come in your back door and somebody says, 'Here's $100,000, now go for it,'" she said. "Therefore, if you're going to do something like that, you need to be as accurate as you possibly can. From the point of view of a scientist, why would want a generic background? If you're going to put something out there that's unique, you don't want to just paint a green tree. You've got to know what kind of leaves to put on it. You have to know how tall it might have grown. You have to know the soil type. You have to know the geochemistry ... you need to know all that. I think what makes this art somewhat different from a great number of art pieces out there is, that care has been taken. If you're going to do generic, you just don't do what I do."
The better-than-generic results of the team's labors are on full display in the book — fossils gathered during the Riches' travels in Australia, New Zealand, Asia, the Americas, Africa and eastern Europe, plus sketches and paintings by Trusler that end up providing a photorealistic view of the past. The artist as well as the scientists are based in Australia, so much of their story is set Down Under. But their work has become known worldwide.
The weirdest pictures come not from the age of the dinosaurs, but from earlier or later — from the Precambrian, for example, a time when body plans apparently took on strange shapes that are hardly ever seen today. Or from the time when giant birds and mammals ruled the roost in Australia, just before the humans arrived.
You won't find feathered dinosaurs amid the pages of "The Artist and the Scientists," but stay tuned. Thomas Rich says he's focusing in on sites in Australia that are similar to China's Liaoning deposits, where the best evidence of dinosaur feathers has been found. Right now he has his eye on fossil beds near Koonwarra. "That's where we should go and look really hard for feathered dinosaurs," he said.
Meanwhile, Trusler is trying to figure out how to render a particular species of ichthyosaur, the ancient marine reptiles that ruled the seas while the dinosaurs held sway on land. "I don't have an idea in my head about what the final appearance of this animal is going to be," he said. "Your creativity is at play to a certain degree all the time, but the ultimate product is quite a mystery."
Thankfully, it's a mystery Trusler doesn't have to tackle alone. That's the main message of "The Artist and the Scientists."
"It's not simply a step-by-step process, in terms of me translating something that's set in concrete," Trusler said. "The process is quite an interactive one, and it always will be."
Be sure to click through "Bringing Prehistory to Life," a slideshow featuring photos and illustrations from "The Artist and the Scientists," published by Cambridge University Press.
Researchers measured the length of fossilized fingers from Ardipithecus and other ancestors on humanity's family tree, then compared them with modern-day species in hopes of figuring out how aggressive and promiscuous long-gone species might have been.
The study, published in the Proceedings of the Royal Society B, draws upon a famous and controversial indicator of social behavior: the comparative length of the index finger and the ring finger, also known as the 2D:4D ratio.
Emma Nelson, an archaeologist from the University of Liverpool, extended the finger-length ratio study to a wide range of species. She and her colleagues measured bones from modern-day species such as gorillas, chimps, orangutans and the white-handed gibbon. They also looked at fossil bones or previously recorded measurements from extinct hominids ranging from Neanderthals (which co-existed with humans until about 30,000 years ago) to Australopithecus afarensis (Lucy's species, going back 3.1 million years) and Ardipithecus ramidus (the oldest human-linked fossil species, going back 4.4 million years).
Nelson argues that comparing the finger-length ratios of extinct and present-day species is a valid technique for making an indirect assessment of our long-gone ancestors' social behavior.
"It is believed that prenatal androgens affect the genes responsible for the development of fingers, toes and the reproductive system," she explained in a news release. "We have recently shown that promiscuous primate species have low index-to-ring finger ratios, while monogamous species have high ratios. We used this information to estimate the social behavior of extinct apes and hominins."
Nelson previewed her findings a year ago at the Society of Vertebrate Paleontology's annual meeting, where she talked about naughty Neanderthals and monogamous australopiths. The newly published paper draws upon additional samples, including the finger lengths for Ardipithecus, or "Ardi." So here are the numbers:
Modern humans averaged a 0.957 index-to-ring finger ratio, and were considered to be on the line between a "pair-bonded," or monogamous, species and a middle-of-the-road species.
Chimps, gorillas and orangutans had index-to-ring ratios in the 0.90 to 0.92 range, and were classified as "non-pair-bonded," or promiscuous.
An early modern human from Israel's Qafzeh Cave, thought to be about 95,000 years old, had an index-to-ring ratio of 0.935. Based on that statistic, the researchers surmised this individual would be more promiscuous than modern humans.
The finger bones from five Neanderthals yielded a 0.928 ratio, associated with even greater competitiveness and promiscuity. Ardipithecus' bones took it up another notch, to 0.899. Two even older primate ancestors, Hispanopithecus and Pierolapithecus, had ratios of 0.848 and 0.908, which means they would have been tough to live with as well.
On the other end of the spectrum, the monogamous gibbons had a 1.009 ratio ... and the australopith sample came in with a ratio higher than that of modern-day humans (0.979). The implication, then, is that australopiths were monogamous.
The big question is whether there's anything substantial to this analysis. Nelson acknowledged that the fossil record was sparse, and that more fossils were needed for study, but she insisted that "this method could prove to be an exciting new way of understanding how our social behavior has evolved."
Other researchers have tried to make guesses about the social behavior of extinct hominid species by looking at sexual dimorphism -- that is, the differences between the male and the female of a species. If the males were significantly larger, the assumption is that they were built to have their way with many females in a promiscuous social setting. This has generated a fair amount of debate, particularly when it comes to assumptions about australopiths.
Nelson and her colleagues suggest that the finger-length ratio could serve as an additional tool for making more educated guesses about ancient social behavior.
"Social behaviors are notoriously difficult to identify in the fossil record," one of Nelson's fellow authors, the University of Oxford's Susanne Shultz, said in the news release. "Developing novel approaches, such as finger ratios, can help inform the current debate surrounding the social systems of the earliest human ancestors."
When this research first came to light last year, University of Wisconsin anthropologist John Hawks cautioned against reading too much into fossilized fingers. He said the index-to-ring ratio "may be correlated with mating system in primates, but that doesn't mean it's a good predictor of mating system. ... As fossil hominins go, I wouldn't expect the story to go any further -- there just aren't many hands, so there's never going to be a significantly predictive result."
Be sure to read Hawks' posting from last year, and feel free to weigh in with your comments below ... that is, after you've finished checking out your fingers.
Update for 2 a.m. ET Nov. 3: John Hawks provided some additional thoughts in response to my e-mail inquiry:
"The 2D:4D ratio really is a subject of a lot of research in psychology and developmental biology, and it really does reflect prenatal hormone exposure. However, it is not a good predictor of any social behaviors.
"In addition to the problem of using a poor predictor, this study has another problem that we often face with fossils -- there are very few of them, and it's not obvious which sample of living primates we should be comparing with them.
"The living apes do vary in mating structure, but they also have huge differences in hand anatomy because of locomotion. Those anatomical differences between species do not necessarily have any relationship to the neurological correlates of prenatal hormones -- even though the variation in hormone exposure is an important cause of variation within species.
"For example, Ardipithecus has fingers and hand proportions that are right within the range of other apes. So when we see that they have a 2D:4D ratio right in the range of other apes, the natural hypothesis is that this reflects their overall hand proportions. Australopithecus, Neandertals and modern humans obviously had humanlike hand proportions, and their 2D:4D ratio may simply reflect this.
"If you were going to do this study right, you would look far beyond the apes to take in many kinds of primates with different social systems. Then you could see whether closely related species have 2D:4D ratios that track their mating systems. Without this, we are really looking at a single evolutionary event -- the rise of the hominins -- which may be unique for many reasons besides mating system."
In addition to Nelson and Shultz, the authors of "Digit Ratios Predict Polygyny in Early Apes, Ardipithecus, Neanderthals and Early Modern Humans but Not in Australopithecus" include Campbell Rolian and Lisa Cashmore.
An assembly of French artist Elisabeth Daynes' reconstructions serves as a "family portrait" for living and extinct hominids. Two australopiths, nicknamed Lucy and Lucien, are in the foreground at right. A representation of the first Homo species to leave Africa raises a rock in the foreground at left. A Neanderthal family is in the far background, and Homo sapiens is represented by the bearded figure stretching out his left hand in the background at right.
The PaleoArt Prize, one of the top honors for artwork related to paleontology, was established in 1999 by art collector John J. Lanzendorf. This year's prize was awarded to Daynes at the annual meeting of the Society of Vertebrate Paleontology in Pittsburgh. The artist was born in the south of France, began her career as a theater makeup artist and has been creating "hyper-realistic" reconstructions of ancient creatures for more than 20 years.
The photo above gathers many of Daynes' masterpieces together for a group portrait. To learn more about the figures, check out the Atelier Daynes website, and particularly the "Reconstructions" gallery.
A Jell-O shot with bugs? These "Mesozoic" shots look like prehistoric bugs trapped in amber ... and contain real edible bugs.
Jurassic bugs trapped in amber? Actually, these are edible bugs trapped in alcohol-laced gelatin. Take some Crick-Ettes (dried crickets that come in three seasoned flavors), mix with gelatin, maple syrup, rum and Snap ginger-flavored liquor, chill into suitably amberish shapes ... and savor the Mesozoic moment. Heck, you could even dispense with the booze altogether and use ginger extract instead, to create non-alcoholic treats suitable for a dinosaur-themed birthday party.
The Mesozoic shots were created by "My Jello Americans," a three-woman team of Jell-O shot artists named Maureen Sheehan, Corinne Kete and Megan Booth. Some of their shots look like deviled eggs or bacon-and-eggs, others like Neapolitan ice cream sandwiches, still others like corncobs. Frankly, they look too good to gulp.
Are there more science-themed shots in the works? "We would love to do more," Kete told me today. "That's definitely where Maureen's interests lie." Kete revealed that "Star Trek" shots are in the works. (Gobble the red-colored Jell-O first.)
How much of each of the ingredients should be used? Sheehan and Kete leave such questions open to experimentation. Others have made a study of this, however. The geeks behind the "My Science Project" website made more than two dozen batches of Jell-O shots with varying proportions of vodka and found that you could up the alcoholic-beverage content to 76 percent by volume (19 ounces of vodka to 3 ounces of gelatin mixture). You could go even higher with sugar-free gelatin (89 percent vodka).