A replica of "Lupe the Mammoth". The bones of this juvenile Columbian mammoth were found along the Guadalupe River.

"This has been my first experience working with the Children's Discovery Museum, or any other museum, in developing an exhibit," says Kaitlin Maguire, graduate student at the UC Museum of Paleontology.

She's been working with the Children's Discovery Museum (CDM), for the past two years as a consultant for their upcoming exhibit, Mammoth Discovery!, that opens on Saturday, June 11th. The exhibit features a replica of the full skeleton of a juvenile Columbian mammoth, Lupe, named after the Guadalupe River where she was found.

"I was brought in to provide the content about mammoths and the history of San Jose during the Ice Age. And so my role has been providing information to the staff here so that they could create the exhibits. That includes little things like what was the vegetation like during the Pleistocene to how old Lupe was, how big [she] was. And also helping with brainstorming to fabrication."

Kaitlin also led the staff on three trips to give them an idea of how a paleontologist works in the field.Two of the excursions spanned the coast from San Francisco to Santa Cruz, where they examined invertebrate fossils, such as shells, and also vertebrate fossils, such as whales and seals and sea lions. They also traveled to Del Puerto Canyon for their third field trip, where they studied terrestrial deposits, or land deposits, that contained fish and plant material. "On each of these field trips, I showed the staff the tools that I use: hammers, picks, notebooks. I also taught them the geology of the area, so they understood the rocks that they were looking at. And I taught them about the animals that they were looking at. In addition, I showed them the proper way to collect a fossil, proper way to document it. Basically everything from start to finish."

She's learned quite a lot from her experiences of working with CDM. "It’s been an incredible experience to understand how an exhibit is built from the brainstorming phase all the way through to fabrication, and the amount of thought to detail, the amount of testing that’s required. I will never go to a museum again and not think twice about the amount of work that went behind building that exhibit. I also have a really, a great appreciation for this museum in keeping everything accurate and unique and true to the story that this mammoth provides us and really staying true to the evidence that is provided by the mammoth and creating a wonderful experience for the children."

Watch "Science on the SPOT: Lupe the Mammoth Comes to Life" on QUEST.

QUEST on KQED Public Media.

Note: In the video, Kaitlin says Lupe is between 2-3 years old. To clarify, "She's older than 2 or 3 years old but probably not older than 10. Paleontologists are not sure of her exact age but do know that she was a juvenile."

37.3272226 -121.8931137

It feels like the world is still shaking from the earthquake and ensuing tsunami that hit northern Japan on Friday. The 8.9 magnitude quake created enormous waves of water, which moved quickly through the ocean and hit the coast of Japan with waves that in some areas were over 10 feet high. This animation shows how earthquakes give rise to tsunamis. When tsunamis hit shore, they can carry with them sediment that they’ve picked up from the bottom of the ocean. This sediment differs from the sediment close to shore, leaving a long-term record of the tsunami’s occurrence.

Paleontologists can look at the layers of sediment along the coast and see records of past tsunamis. They can also see that before tsunamis occur, the land along the coast often starts to subside, as one tectonic plate slips underneath another. The clue that tells paleontologists that the coastline tilts before an earthquake is a group of tiny marine organisms, called foraminifera. By studying these organisms in the sediment along the shore of the West Coast, scientists can learn how frequently tsunamis occurred here in the past, and whether we can predict a big quake in the future.

The tiny marine organisms in the sediment are called foraminifera, or forams for short. They are protists—neither animals nor plants, protists are a grab bag of simple organisms that includes amoebas, seaweeds, and single-celled algae. Forams are unicellular, and they build a shell, called a test, out of calcium carbonate. The test has little opening from which pseudopods—thin strands of the cell’s cytoplasm—protrude. The pseudopods help the forams move around. However, it is the calcium carbonate tests that make forams so useful as records of geological events.

The tests of foraminifera are often well preserved in marine sediment, as fossils. Forams evolve relatively quickly, so micropaleontologists (folks who study tiny fossils) can determine the age of the sediment by identifying the species of foram that is preserved. Also, each species of foram can survive only in a narrow range of environmental conditions. If the water is too salty, a given species can’t survive; if the water is too fresh, that species won’t survive either. The salinity of the water has to be just right. This means that micropaleontologists can use foram fossils to estimate the salinity of the water in the past. (For similar reasons, forams are also good indicators of the proximity of oil deposits, and a good proxy for past climates.)

A few years ago, UC Berkeley Professor Emeritus Jere Lipps and a few colleagues, including Dalhousie University professor David Scott, travelled along the coast from Alaska to Baja, taking cores of coastal sediment along the way. They found that several years before a big earthquake and tsunami, the foram composition in the sediment changed slightly. The forams shifted from species that live in very slightly salty water to species that live in water that is even saltier. This is a sign that the land had begun to tilt downward towards the ocean.

The Pacific plate is slowly sliding underneath the North American plate. But the plates stick together, and the edge of the North American plate gets pulled down slightly along with the Pacific plate. Suddenly, the plates will un-stick; the North American plate will release and move upwards again, and the Pacific plate will slide underneath. This kind if quake is called a megathrust earthquake. Dr. Lipps and his colleagues found that there have been three megathrust earthquakes, preceded by a tilt in the coastline, over the past 3000 years.

Forams are good measurements of past coastline tilt. But to measure coastlines in real time today, scientists can deploy seismometers. By placing seismometers in areas that have undergone a pre-earthquake tilt in the past, we may be able to detect early warning signs of potentially destructive megathrust earthquakes and resultant tsunamis.

37.879329 -122.2463347

Geologic map of Caldecott Tunnel area (credit: USGS ) Click here for a larger version.

If you use Highway 24 as part of your daily commute you are already familiar with the Caldecott Tunnel, which connects Orinda and Oakland — perhaps you are too familiar with the tunnel as you sit in the bottleneck traffic waiting to enter it. What you may not be familiar with, however, is the geology of the hills through which the tunnel was constructed. There are currently three separate tunnels, or bores, that make up Caldecott Tunnel. Construction for a fourth bore is now underway an is already yielding interesting geologic results. The Caldecott Fourth Bore Project website contains a wealth of information about the entire project — from funding to logistics to tunneling methods and more.

The process of excavating a tunnel produces a lot of rock and, in this case, it is sedimentary rock that is known to contain abundant fossils. The geologic map shown above depicts the distribution of distinct rock types and ages in this area. The part of the ridge that Caldecott Tunnel cuts through is made up three formations — each of which has their own color: The Orinda Formation is the orange unit at the east portal, the Claremont Chert in yellow, and an unnamed mudstone in brown at the west portal. The tectonic forces that created these hills also caused the layered sedimentary rocks to be tilted at high angles and, in many areas, the layers are standing up vertical. The rocks are older from east to west so, in this case, excavation of the tunnel from east to west is similar to drilling down into older layers.

Orinda Formation along Hwy 24 near east portal of Caldecott Tunnel (credit: Jeff Weiss, public information officer for Fourth Bore Project)

The rocks are lithified sediments that were deposited in the Miocene period, which ranged from 23 to 5 million years ago. The Orinda Formation (the orange unit by east portal in map above) is approximately 10 million years old and is known to contain abundant mammal and plant fossils in nearby areas. The Orinda Formation is characterized by a wide variety of sedimentary rocks including mudstone, sandstone, and conglomerate that were deposited in streams in creeks (see some photos of the rocks near the tunnel here.

Some mammal fossils found in the Orinda Formation include*:
•    Gomphotherium (a primitive type of elephant)
•    Hipparion, Nannipus, and Pliohippus (primitive horses)
•    Barbourofelis (member of primitive cat family)
•    Cranioceras (deer-like mammal)
•    Ticholeptus (member of extinct group of pig-like animals)
•    Desmostylus (exctinct sea cow similar to a hippopotamus)

The Miocene was the peak of mammal diversity and thought to be linked to the development of grassland ecosystems. So, next time you’re stuck in traffic leading up to the tunnel remember that you’re driving through the geologic evidence of a past Bay Area environment. Excavation of the fourth bore is really just getting started so stay tuned for more in the coming months. I will do my best to find out what I can and blog about it here for QUEST.

-

* List of mammal fossils from University of California Museum of Paleontology database. If you want to learn more about specific species, you can learn a lot by simply googling the italicized names in the list above.

37.85822548033667 -122.21365928999148

Artist's rendering of A. afarensis using stone tools. By Viktor Deak, copyright California Academy of Sciences

Originally reported for KQEDnews.org.

The next time you reach for your high-carbon, stainless steel chef’s knife to trim the excess fat off a bone-in Porterhouse steak, you may want to raise a glass to your ancestors who roamed Africa millions of years ago.

A Bay Area researcher and his team made a startling discovery when they unearthed a pair of bones recently in northeastern Ethiopia: the earliest evidence of stone tool use by upright human ancestors 3.4 million years ago – nearly a million years earlier than scientists previously had believed.

“The moment that sort of primitive species, not so primitive anymore, started to use those tools, it started to open up the type of species we are today,” said Zeresenay Alemseged, chair of the anthropology department at the California Academy of Sciences in San Francisco.

“That primitive stone tool they made 3.4 million years ago is the precursor for all the technologies that we have today.”

Alemseged’s research appears in Thursday’s edition of the journal Nature.

Zeresenay Alemseged in his office at the California Academy of Sciences. Photo by Sheraz Sadiq

Meat at the ancient watering hole

The discovery could help rewrite understanding how humans evolved, because stone tool use and meat eating were key steps taken along the evolutionary path leading to the big-brained species we are today.

“Brain tissue is extremely expensive to grow and maintain, so meat provided a dense source of calories, and additional nutrients like fats and proteins that are important for growing big brains”, said Teresa Steele, a professor of anthropology at the University of California-Davis.

The species at the center of the research bore only a passing resemblance to today's Homo sapiens. Known as Australopithecus afarensis, the human forebears were long-limbed, about four feet tall, resembling chimpanzees that walked upright but also partially lived in trees. They were thought to have eaten mostly leaves and fruits. But now scientists have a more accurate picture of their diet and behavior.

“This new discovery clearly shows that the picture we had was wrong, because the species was not only using tools, but was using tools to interact with large mammals, to exploit meat from very large mammals and no other non-human species can do that,” said Alemseged.

They weren’t so much hunting their meals as scavenging them, he said, because their legs weren’t built for chasing prey. Alemseged believes they would venture into the open grasslands of East Africa to find dying or recently deceased animals, like antelope, and use their tools to obtain the nutrient-rich meat. Then, they would need to work as a team in a landscape teeming with other hostile, hungry predators.

“When some were using tools to carve the meat off the bone or break the bones to access the marrow, some maybe were watching for hyenas or lions. And that’s why I can confidently say that when we revise the textbooks for the earliest evidence for stone tool use and meat eating, we will have to revise also the picture of the species Australopithecus afarensis on the ancient landscape,” he added.

The behavior suggests a certain level of intelligence and planning, which is impressive considering that “Lucy,” a partial skeleton of Australopithecus afarensis unearthed 36 years ago, had a brain that was roughly a third the size of a human brain, which first started cogitating in modern human form about 200,000 years ago.

Humans and chimps share a common evolutionary ancestor, and chimps also use tools, such as twigs to dig for termites in mounds or rocks to break open nuts. Humans, however, are the only primate species to intentionally make sharp-edged tools to hunt or scavenge prey much larger than themselves.

Fossilized bone fragments from Dikika, Ethiopia that show evidence of stone tool use. Copyright California Academy of Sciences.

Leaving no fossil unturned

Alemseged’s latest discovery grew out of the Dikika Research Project, which he has led since 1999, looking annually for fossils in the Afar region of Ethiopia — a dry land once dotted with forests and grassy savannahs on which the earliest upright human ancestor would have taken its first two-legged steps six million years ago. In early 2009, just six miles from where Lucy was found, this “cradle of mankind” as Alemseged calls it, offered up the tantalizing find announced this week.

“We took everything back to the camp and a group of us was sitting in the camp and just everyday going through each bone. And then our paleontologist noticed something on the foot bone of an antelope, and when we looked at it, there were cut marks evidently,” Alemseged said.

Although that bone didn’t turn out to have the cut marks that were indicative of stone tool use, two bone fragments did – one from the rib bone of a cow-like animal and one from the leg of a goat-sized antelope. But the team had to be sure, because the marks could have been caused by abrasion over the years or by the teeth of another predator. So Alemseged received permission from the government of Ethiopia to send the bones out of the country to Arizona State University, where they were examined by high-tech forensic tools.

An environmental scanning electron microscope enlarged the cut marks to reveal a pattern consistent with a scraping and pounding motion from a sharp-edged stone tool. Within one of the cut marks on one of the bones was further irresistible proof of early human activity.

“We discovered a rock that has a completely different chemical composition from the bone itself. So that means that it came into the cut mark when someone was using a sharp-edged igneous rock to cut the bone or the meat. Based on chemical analysis we were able to show that that cut mark was made by stone and done before the fossil fossilized,” Alemseged said.

Since massive volcanic eruptions 3.42 and 3.24 million years ago spewed layers of volcanic ash into the basin where the cut-marked bones were found, dating the bones was relatively straightforward. The research team settled on a date of 3.4 million years because the bones were found in a sediment layer close to the layer containing the volcanic ash from 3.42 million years ago.

Under a microscope, one of the bone fragments reveals evidence of a scraping motion. Photo courtesy of Hamdallah Bearat, Arizona State University

Where are the tools?

Alemseged, a 41 year-old, Ethiopian-born paleoanthropologist, had already made a name for himself with his discovery in 2000 of “Selam,” the oldest and most complete remains of an Australopithecus afarensis child who lived more than three million years ago.

As he once more enters the world of this ancient human ancestor, a key mystery remains.

“The most obvious question is, ‘where are the tools?’”, said David Braun, a senior lecturer at the University of Cape Town in South Africa who studies fossils bearing marks of early stone tool use. “These early tools will actually represent the dawn of human culture and will likely be difficult to identify”, said Braun.

The oldest found stone tools – made of basalt, quartz and flint – were also discovered in Ethiopia, dating back some two and a half million years ago. If they still exist, it will be a challenge to find stones with sharp, flaked edges that could have been used to butcher meat more than three million years ago, now dispersed and lying hidden for millennia under layers of soil. And while these ancient human ancestors now appear to have been using tools, whether they actually made them is likely to be a subject for debate. “There is currently no evidence that they actively chipped stone to make tools. The earliest tools are most likely sharp-edged stones that were opportunistically used”, said Braun.

When they’re in the field, Alemseged and his team of scientists and graduate students works up to 12 hours a day, seven days a week for a month or more, combing an area not just for large, readily identifiable bones, but also for fragments which require further scrutiny.

“The fact that we made this discovery is because we changed the way we were collecting the fossils, so we need to continue to look for more cut-marked bones and really show that it is a standard thing to do and then find the stone tools that were used to inflict those marks on the bones,” he said.

“We’re trying to address one of the most important questions in humanity: who we are and where do we come from. This individual who carved that stone tool contributed to your genes, my genes, to every person’s genes on this planet.”

37.7699 -122.467174

Trying to use DNA to prove the Starchild is half alien.

Let’s say you found a bone and you thought it came from an alien. How could you possibly prove such a thing?

This isn’t something I had given, well, any thought to before but I recently got some questions at Ask a Geneticist about this sort of thing. Which got me to thinking about what it would take to convince me that a bone came from Outer Space.

I guess if you found an intact skeleton that was wildly different from anything on Earth I’d have to take the idea that it came from an alien life form seriously. If you found a skeleton of one of the aliens from Independence Day, for example, that would have to give me pause. (And odds are that aliens would be way weirder than this.)

Another possibility is if you found a bone in some layer where it shouldn’t be. For example, if you found some complicated skeleton in a Pre-Cambrian layer and if you could rule out the many possible trivial explanations, then I might have to believe the skeleton came from elsewhere.

The one thing you almost certainly could not do in these cases is any sort of DNA study. DNA has proven to be a wonderful molecule on which to base life here on Earth but there’s no reason to think that an alien life form would need it.

In fact, if we found alien life that was based on DNA, then that might lend some support for some sort of panspermia model for life on Earth. In other words, life started elsewhere and was seeded here on Earth (and possibly lots of other places too).

What you need for life is something that can make copies of itself almost perfectly*, is stable, and can carry a message. There are probably many different chemicals that fit this bill.

Unfortunately, without knowing something about this alternative genetic material, we probably could not make any sense of it even if it was hiding in some alien bone. Maybe we’d find some sort of chemical that was similar to DNA in that it had lots of repeating units. But we wouldn’t be able to read it. And we’d be hard pressed to figure out how it works without something living to put it into.

Of course, this assumes that whatever molecule stores the alien’s information is stable enough to be found. If the bone was very old, the molecule would have to be much more stable than DNA.

Scientists have gotten very good of late at reading the DNA of long dead creatures. They’ve even managed to piece together all of the DNA of a Neanderthal who lived tens of thousands of years ago. But they can do this because they know how DNA works and can exploit that knowledge to make lots of DNA from the scraps left behind.

Without knowing how the alien storage molecule works, we couldn’t make more of it. Which means there needs to be a whole lot there for us to even get started on understanding it.

What all of this comes down to is that in most cases it would be impossible to use any sort of genetic analysis to prove something was of alien origin. Except for a few rare cases, you’d need to rely on where the bone was found or what the intact skeleton looked like or if it was clutching some bit of advanced technology. The best proof would probably be meeting one in person…

*The almost is key here. You need for there to be some error rate so that evolution and natural selection can happen.

37.7749295 -122.4194155

Scientists used evolutionary theory to figure out where
to find the bones of this fishibian.

What is so great about this book for a scientist is that it gives the big picture on evolution. This sort of thing can be hard to get sometimes because we scientists are so specialized. As I like to tell people, I worked on a single amino acid of a single human protein for my postdoctoral project. For three years.

Coyne's book synthesizes genetics, anatomy, biogeography, physiology, paleontology, geology, and lots of other "ologies" to show how strong the case is for evolution. This is great for me because, of course, I tend to focus on genetics and molecular biology and spend less time on the other fields. Which means I miss important, subtle nuances to some big findings.

For example, I had heard about the fossil of Tiktaalik roseae that was found in 2004 that linked fish to amphibians. This was a huge deal because the animal that the bones came from had characteristics of both fish and amphibians. And it appeared in the fossil record at the right time to be a transitional animal between the two.

What I hadn't fully appreciated was that the scientists decided to look where they did based on how old they thought the fossil should be. In other words, they were able to use the theory of evolution to predict where to find the fossil they were looking for.

They knew from previous fossil finds that something like Tiktaalik roseae would have appeared between 360 and 390 million years ago. The scientists also knew from previous research that the beast would have been in freshwater. So they got out a geological map and looked for places that met these criteria. They settled on Ellesmere Island in Canada and after five years, they found this marvelous fossil.

This is important for a lot of reasons. One is that it obviously tells us a lot about how vertebrates emerged onto dry land. Another is that it provides further validation of geological dating methods. They had to rely on these methods to know where to look for the fossil and the methods worked.

This find is also important because it is based on a prediction made by evolutionary theory. Around 390 million years ago, the only vertebrates were fish. By 360 million years ago, there were four-footed vertebrates on land. So the scientists looked in a place that was 375 million years old.

Scientists used evolution to make a testable prediction that turned out to be true. And evolution came through with flying colors like any good scientific theory should.

37.332 -121.903

There are dozens of events celebrating Darwin this month. You can also join QUEST at one of them. On February 26th, QUEST will be screening our half-hour documentary, "Chasing Beetles, Finding Darwin" at the California Academy of Sciences. We'll be joined by two scientists featured in the story. You can get more info or buy tickets here.

Listen to the Investigating Darwin's Legacy radio report online.

37.42099 -122.20607

Methane concentrations revealing a plume in Mars' northern
hemisphere during its summer season. Credit: NASA

We've known about the existence of methane gas on Mars for several years now, from independent observations.  Further observations have led to the detection of "plumes" or clouds of methane gas apparently emanating from specific locations on Mars.  One plume is estimated to contain 19,000 metric tons of the stuff.

Why is this exciting news? If you know anything about the source of most of Earth's atmospheric methane gas, you already know the answer:  possible life.  Not, I should say, necessarily life on Mars, but maybe a strong piece of evidence in that direction.

On Earth, methane (CH₄) is produced by living organisms—mostly by the activity of microbes, but some by the digestive processes in larger organisms (yes, like humans, and cows).  Methane is the major constituent of natural gas, which fuels gas powered ovens and heaters in homes, as well as natural gas power plants.  Methane is also produced by decaying organic matter—that's where "swamp gas" comes from.

On Mars, methane gas cannot exist for long in the atmosphere; it is relatively quickly broken down by solar radiation.  So, the methane detected in Mars' atmosphere must be replenished by something, continually.

So the big question right now is, where is the methane coming from? Under the surface of Mars, almost certainly.  By biological processes—life—underground? Could be.  By non-biological means? Could be, too; methane can be produced through inorganic chemical processes.  We don't know yet.  The next step in finding out more will be the Mars Science Laboratory, a large rover scheduled to be launched to Mars sometime in the near future.

In one form or another, humans have been trying to see, or find, life on Mars for a long time.  Percival Lowell squinted at Mars' small, blurry disk through his 24-inch telescope in Flagstaff, and perceived markings he saw to be vast canal complexes, ostensibly built by a desert Martian civilization thirsty for water harvested from their planet's polar ice caps. This led to much of the science fiction relating to life on Mars in the 20^th Century.

Earth-bound telescopes noted seasonal changes in Mars' color and brightness, and some attributed this to possible seasonal growth of Martian vegetation—though it was later found that these variations were the effects of seasonal planet-wide dust storms.

The Viking landers' primary mission in the 1970's was to search for life.  They didn't find any by scratching around Mars' surface and testing the soils there.

The 1990's saw the controversy over microscopic structures in meteorites found on Earth but determined to have originated on Mars.  Some argued that these structures were fossils of Martian microbes that lived on Mars long ago.  Whether these findings were in fact fossils and not just geologic structures was never conclusive.

The determination that liquid water once flowed on the surface of Mars, and still exists under its surface at least as ice, is pretty much scientific fact today.  Evidence of past liquid flows have been imaged and mapped from space, and the Phoenix lander found water ice in the north polar regions last year.  And there's the rover Opportunity that has confirmed gray hematite, a mineral that forms in the presence of water.

It's almost certain that there are no Martian cows grazing the rusty desert plains out there.  But there seems to be a lot of evidence for the possibility that something is going on below Mars' surface—perhaps the presence of liquid water, perhaps the presence of some form of life.  We don't know yet, but it sure feels like we're onto something here….

37.8148 -122.178

That was one of the things we wanted to document when we began our exploration of Briones Regional Park, just east of Berkeley. This park is a favorite spot for locals, but is also home to some amazing wildlife. With the help of East Bay Regional Parks naturalist Meg Platt, we put together a science hike where you can see some of the amazing things the park has to offer. But you'll also notice on the map that we didn't pinpoint exactly where the newts live.

As Meg described, this is a fragile species and thanks to Parks District's work, the newts are able to thrive in Briones and several other East Bay parks. But it's important for hikers and park users to give this species plenty of space, especially during mating season. Make sure to keep dogs out of the park's ponds. Luckily, the East Bay Regional Parks district puts together programs for the public so everyone can safely discover this amazing species.

Check out the interactive map of the Briones exploration online, and watch our audio slide show about California Newts.

Lauren Sommer is an Associate Media Producer for QUEST.

37.9275 -122.15554

A wishbone from a theropod and a turkey.

What you may not know is that we can find homologies of many birds parts — thigh bones, arm hones, and even wishbones — in our own skeleton, and it's not happenstance. The ultimate reason for this similarity is ancestry: birds, mammals and all other tetrapods (four-legged, air-breathing vertebrates) share a common ancestor, over 300 million years old. And, as the descendents, we all exhibit the same basic body plan, with additional anatomical refinements specific to each evolutionary history. Whether a tetrapod's arm is a fin, a wing or a limb throwing a baseball, a common structure is shared among them because of their evolutionary past.

Back to turkeys: in your holiday meal, you may have come across a very particular y-shaped bone: the wishbone. (The one from my turkey is drying on the counter above the kitchen sink). Humans actually have homologues of wishbones, but we don't call them that — they're our collarbones, or clavicles. These bones are long and slender, and they form a key part of complex of bones and muscles that allow us to move our arms. Living birds are unique among tetrapods in having clavicles that are fused together into the y-shaped structure called a furcula, and it plays a key roles in allowing birds to fly. Furculae stiffen the thoracic skeleton, and, in conjunction with a keeled breastbone (or sternum), they provide key muscle anchors for the unique flight stroke of the bird arm.

So, how did two bones get fused into one? Birds are descended from one particular line of dinosaurs called theropods, which includes dinosaurs like T. rex or Velociraptor. Over the last 20 years, paleontologists have assembled a detailed picture of the family tree, or phylogeny, of these animals, showing the exact anatomical changes that occurred along the lineage of theropods to living birds. The changes in the furcula plays a key role in this evolutionary sequence: it turns out that relatives of T. rex and many other theropods had fused furculae, but clearly these animals did not use the fused furcula to fly. Some paleontologists have suggested that fused furculae in theropods increased the mobility of the forelimbs. Then, as birds evolved flight, a fused furcula turned out to be wonderfully useful as a brace for a flapping limb.

Evolution often works in this manner: recruiting old structures to use in a new context, and many examples of such improvisation have been shown in the fossil record. Together, phylogeny and the fossil record reveal more about evolution that might not have been apparent when you were first biting into that savory chunk of turkey meat. To check find out more about your holiday dinosaur, check out this link too.

Nick Pyenson is a PhD candidate at the University of California, Berkeley, in the department of integrative biology and the museum of paleontology.

latitude: 37.7819, longitude: -122.286