On October 19th, 2017 we learned about

New evidence necessitates the reevaluation of species that survived past their supposed extinctions

It seems like it’d be hard to miss an animal the size of a lion named for its serrated, sword-like teeth. An animal like Homotherium latidens, or the European scimitar cat, was once one of Europe’s most formidable predators, at least until 300,000 years ago, when it seemed to have gone extinct. However, a jawbone pulled from the North Sea is rewriting that timeline by 270,000 years, as both carbon dating and genetic evidence suggests it was alive as recently as 28,000 years ago. This younger specimen is now raising a lot of questions, as new causes for extinction, new ecological niches and that giant gap in the fossil record all need to be reconsidered.

Homotherium were like slightly scaled-down versions of their more famous saber-toothed cousins, like Smilodon. Nonetheless, this cat still had two large, canine teeth, and their knife-edge shapes suggest they were probably used for cutting and slashing rather than simply impaling prey. It’s hard to know for sure, because the humans that we now know lived as neighbors to these scimitar cats unfortunately didn’t leave any good field notes behind. Even cave paintings of predatory cats found in norther France somehow omit any solid portraits of H. latidens.

Missing, or migrating?

One of the possible explanations for Homotherium’s absence in the fossil and written record may be that they just weren’t around much. One hypothesis to explain how the cats could be alive without leaving behind more evidence is that they had gone on a very long migration, possibly even around the world. This idea is slightly bolstered by some the fact that the cats’ closest relatives are known to have turned up in North America, although that relationship is also being reexamined.

Looking at the mitochondrial DNA recovered from the new jawbone, researchers were able to not only date the specimen, but also see where it fits in the larger cat family tree. They found that H. latidens is remarkably similar to its North American kin, Homotherium serum— so much so that it’s been suggested that they might be the same species in a new location. This similarity is in contrast to H. latidens’ relationship with other cat species, which forked away from each other 20 million years ago. While they do share a common ancestor, your house cat is more closely related to a modern tiger than Homotherium is to other saber-toothed cats like Smilodon.

Assuming that we’ve now found the most recent H. latidens bone on the planet, scientists now have to think about what caused its final extinction 28,000 years ago. As presumptuous as it sounds, there’s a fair chance that these cats really did go extinct at that point (really!) if only because so many other animals were being removed from the food chain around the same time. Europe was experiencing an ice age at that point and coming to grips with more efficient human hunters. The combined ecological stresses likely explain not only the extinction of these saber-toothed cats, but other megafauna like mammoths and cave bears as well.

Other exaggerated extinctions

Balbaroo fangaroo
Balbaroo fangaroo, who’s name may never be topped

As big an upheaval as this new bone has caused, it’s worth remembering that this isn’t the first time paleontologists have had to rethink extinctions. You can’t predict what fossils will be found, and while most species seem to cluster geographically and chronologically, they can surprise us with their extended survival. Just this month, another extinct mammal with big teeth extended it’s timeline, but by five million years. Fanged kangaroos like Balbaroo fangaroo weren’t exactly impressive predators, as they were browsing herbivores that scurried around ancient Australia, but they apparently did better than we’d previously given them credit for. Like the European saber-toothed cats, the pressures that drove them to their (final!) extinction is now be rethought, since in their case they seem to have outlived their regions major climate crisis known to have taken place 15 million years ago.

Source: This Saber-Toothed Cat Mingled With Modern Humans by Michelle Z. Donahue, National Geographic

On October 5th, 2017 we learned about

Modern technologies help reveal digestive details in otherwise opaque fossils

230 million years ago, a lungfish was dining on scaly fish in Poland. 200 million years ago, a young ichthyosaur ate squid for the last time near England. 40 million years ago, a salamander made the somewhat prescient decision to swallow a frog in what is now France. No human was there to witness any of these events, but we can find evidence of these meals by looking into fossils to see what turns up in ancient stomachs and feces. This isn’t always easy though, since stomach contents tend to get jumbled under the best conditions, and more often are smashed and obscured by the passage of time. Fortunately, new techniques and scanning technologies are letting us look inside these fossils without needing to destroy them in the process.

Peering through fossilized poop

Fossilized feces, called coprolites, can be dense packets of information, but their understandable lack of structure makes them tricky to dig into without making a mess of things. Paleontologists want to avoid simply cracking them open, as they’re more likely than your average skeleton to include fossilized soft tissues that were protected by the poop that surrounds them. To look at these once-stinky treasure troves of digestive data, researchers have been using synchrotron microtomography to essentially x-ray coprolites and build 3D models of their contents, all without damaging the original specimen. In a batch of coprolites from Poland, this has revealed swallowed fish fin rays, scales and uncrushed beetles that were originally eaten in the Triassic period 230 million years ago.

Baby’s first, and last, swallowed squid

A 200 million-year-old ichthyosaur posed a different kind of challenge. The 27-inch, baby Ichthyosaurus communis clearly had hook-like structures nestled between it’s well-preserved ribs which were eventually concluded to be the corpse of a swallowed squid. While getting a fossil of a normally squishy creature like a squid was a great find, the ichthyosaur was hard to work with because there was no record of where it was excavated. Without knowing which layers of sediment the fossil originated from, researchers had to come up with other ways to date this marine animal’s last meal.

The solution was to try and date the microscopic fossils of other marine life embedded in the rock surrounding the skeleton. Based on the types of so-called microfossils that were contemporary to the ichthyosaur, paleontologists were able to estimate that this specimen lived in the Jurassic period sometime between 199 to 196 million years ago. As this technique is refined, it may help researchers around the world, as many museums have poorly documented specimens needing some kind of context before they can be properly studied.

Scanning a salamander’s soft tissues

When we think of eating habits, we often focus on teeth and jaws, but an amazingly well-preserved salamander is offering a lot of detail from just it’s trunk. The headless Phosphotriton sigei not only preserved its last meal within its ribs, but also elusive soft tissues like lungs, muscles and even glands. All this detail again poses the challenge of figuring out to take a look at each organ without destroying the specimen in the process.

Fortunately, the paleontologists who first collected the fossil in the 1870s were patient enough to leave the salamander essentially untouched. This meant that now, 147 years later, researchers had an intact specimen to scan with synchrotron tomography, building a virtual model of all the preserved anatomy. In addition to details about the salamander’s body, we also know that its last meal was a frog, bones and all.

Food for thought

Interestingly, both the ichthyosaur’s squid and the salamander’s frog were noted as being unusual choices for those species. Other baby ichthyosaurs from later in the Jurassic period have been found with small fish in their tummies, not squid. Salamanders are noted as being opportunistic eaters, but generally aren’t known to eat frogs or other amphibians. There’s a good chance that this represents a shift in dietary preferences that wouldn’t otherwise be detectable in an animal’s own anatomy alone, showing how finding an animal’s food offers unique insights into their lives. Or maybe, just to really speculate here, it’s that both animals made a bad choice, and that somehow the squid and frog weren’t just last meals, but also their cause of death?

Source: Prehistoric squid was last meal of newborn ichthyosaur 200 million years ago, Phys.org

On October 2nd, 2017 we learned about

Modern frogs with a big bite predict that Beelzebufo ampinga had a monstrous mouth

Every kid knows that frogs eat bugs, overlooking the fact that many species also put fish, snakes, rodents and even other frogs on their menu as well. That list got some interesting additions lately, with a prehistoric frog species, Beelzebufo ampinga, being found capable of consuming small dinosaurs. Nobody today has had the privilege of being bitten by these ten-pound amphibians, but analysis of some of their surviving relatives suggests that the so-called “devil frogs” may have had a stronger bite than a German Shepard.

The study started with much smaller, safer mouths. South American horned frogs in the genus Ceratophrys are the current big bite kings among frogs, although they they don’t grow nearly as large as their extinct counterparts. Instead of relying on the typical, and amazing, tongue-snare techniques other frogs use to capture small prey, Ceratophrys are ambush hunters that wait to surprise and gobble up animals nearly the same size as themselves. When measured with a device called a force transducer, the a frog with a mouth under two inches could bite with around six-and-a-half pounds of force. That’s not enough to even break your pinky, but it’s not bad for such a tiny creature.

Bites from bigger mouths

From the initial measurement of a daintier Ceratophrys frog, researchers then calculated what a bigger set of the same jaws could do. Strength is dependent on muscle and bone size, so scaling up a Ceratophrys mouth quickly makes for a more impressive bite. With a four-inch mouth, a Ceratophrys bite becomes comparable to a toad-headed turtle, although your finger bones might still survive a single chomp. Taking these calculations further, B. ampinga was even larger, and thus was probably capable of biting as hard a wolf or smaller tiger. With that kind of strength, biting through bones and entire bodies would be a possibility, which is why small dinosaurs like hatchlings would have been a practical meal option for these formidable frogs.

Before you rush off to argue about B. ampinga vs. T. rex, it should be noted that these are estimates. B. ampinga has very very similar skeletal anatomy to today’s horned frogs, but it wasn’t a perfect match. The ancient devil frogs had slightly longer, shallower skulls, which may have reshaped the musculature into a less powerful configuration. Still, even with some allowances, these mouths were likely bad news for anything that could fit inside.

Source: Bite force research reveals dinosaur-eating frog, Eurekalert

On September 28th, 2017 we learned about

How theropod dinosaur heads were reshaped to build the beaks and brains of modern birds

How did evolution build a chicken out of Tyrannosaurus parts? There’s no doubt that modern birds evolved from theropod dinosaurs millions of years ago, but scientists still want to know exactly how that transition occurred. Anatomy usually doesn’t appear or reappear all at once, but is instead resized and reshaped into forms that will better serve a creature in its changing environment. However, when it comes to the transformation from a T. rex to a chicken, some more dramatic swaps somehow took place across dinosaurs’ skulls, particularly with vanishing teeth and the rise of big beaks.

Thorough investigations of swaths of reptiles, dinosaurs and birds have found that the transformation from a theropod’s toothy snout to a bird’s hard beak had its roots in the individual life-cycles of various theropods. Limusaurus inextricabilis was a theropod that was born with teeth, but lost them entirely by the time it was an adult. Computed tomography (CT) scans of Limusaurus skulls found that even after this change took place, the adults still had tooth sockets in their lower jaws. Their mouths became beaks because those sockets were basically covered up by a sheath of material called keratin.

Developing a beak from birth

Keratin is a fibrous material that all kinds of animals use to grow a huge variety of structures on their bodies. Keratin can form hair, horns, feathers, claws and fingernails, all with the possible advantage of being a flexible at smaller sizes, to help avoid breaking, while also being easier to replenish than harder materials like enamel-covered teeth. So while a creature like Limusaurus gave up meat-slicing teeth as it aged, it was gaining a strong, repairable beak that could still help it capture all the calories it needed.

Of course, modern birds don’t have to wait until they’ve fledged to enjoy the benefits of a beak. Researchers believe that over time, avian dinosaurs started the process of growing their keratin sheaths earlier and earlier in their lives, eventually starting before hatchlings even exited their eggs. At some point, this meant that these dinosaurs skipped their toothy phase altogether, jumping straight to a beak from the beginning. Unsurprisingly, the gene that seems to spur beak growth, BMP4, has also been found to suppress the development of teeth, putting this whole transition together in a single mechanism.

Shaping skulls for bird brains

There’s more to being a bird than a hard beak though. Our modern feathered friends also generally have proportionally bigger brain cases than their ancient relatives, generally with a rounder, roomier shape over all. A separate study again looked at skull anatomy across reptiles, dinosaurs and birds, and found that while reptile heads don’t show a ton of change in the fossil record, there’s a bigger jump from non-avian dinosaurs to modern birds. Researchers believe that as the bird brains got bigger, the frontal and parietal bones in the skull basically had to balloon about to accommodate them. They don’t yet have anything as concrete as a single regulatory gene to point to, but the advantages of a bigger brain seem like an obvious evolutionary pressure to warrant reshaping the back of a species’ skull.

Source: How did dinosaurs evolve beaks and become birds? Scientists think they have the answer by Michael J. Benton, Phys.org

On September 21st, 2017 we learned about

Bits of shell in fossilized poop suggest that hadrosaurs sampled crayfish as dietary supplements

Oh dear. Just what have the hadrosaurs been eating? Based on the shape of their teeth and jaw structure, it’s a safe bet to say that hadrosaurs were herbivores. Chewing and grinding up tough plants would have been no problem for these multi-ton dinosaurs, but that doesn’t mean that they only ate greens. Close examination of coprolites, or fossilized poop, from hadrosaur territory suggests that between huge helpings of salad, creatures like Gryposaurus or may have also stopped to snack on less-leafy fare, like rotting logs and even small crustaceans. Nobody is about to reclassify hadrosaurs as omnivores at this point, but the contents of this poop has raised questions about what motivated these meals, and how frequently they occurred.

More than a single serving

The coprolites in question come primarily from Utah. Before any crustaceans were detected, the poop caught paleontologists attention thanks to an unusual amount of wood that had been eaten. Analysis of the wood found that it was most likely from rotting logs, complete with traces of fungi from millions of years ago. The wood was consistent with other coprolites attributed to Maiasaura hadrosaurs from an earlier dig in Montana. There are scenarios where cows have been found to eat rotting logs with some gusto, providing a chronologically-reversed bit of precedent for herbivores eating material that’s not generally digestible.

The coprolites from Utah of course held even more treasures, with pieces of crustacean shells turning up in 10 of the fossilized feces. The fact that those feces were found in three rock layers across a 13 mile range, alongside the excreted wood, strongly suggested that there was a larger pattern, rather than a fluke case of a bug being caught in a Gryposaurus‘ lunch. The pieces of shell were thin and broken, indicating that they had been eaten and embedded in the poop, rather than being fossilized on top of it later on. While a specific shell-holder hasn’t been identified, bits of claw indicated that the hadrosaurs were eating something like a crayfish or crab, as opposed to an insect or other shelled animal.

Packed with calcium and protein

So with all this evidence that hadrosaurs were eating meals of crayfish over rotten log, we have to of course ask what would motivate this behavior. Paleontologist Karen Chin points out that the largest specimen was around two inches in length, which would have been big enough for a hadrosaur to notice and spit out if it was undesirable. When coupled how often these critters turn up in hadrosaur poop, it stands to reason that the hadrosaurs were purposely eating these crustaceans. Looking again to modern animals, birds are known to eat extra protein to prepare for producing offspring and eggs, which these crustaceans would have provided. Mammalian herbivores are also known to dabble in a bit of bone-munching from time to time, again as a form of nutritional supplements. Assuming these modern animals can be used as models, the hadrosaurs probably dug into into soggy logs to get some extra protein and calcium before mating season.

Other researchers caution about attributing motivation when all you have to work off are fossilized poop, or even fossilized skeletons. While the crustaceans were in some cases large enough to be detectable, it doesn’t mean the hadrosaurs were seeking them out. Wood and exoskeletons also fossilize more easily than softer plants, and so we can’t be sure of how representative these ten poops are of a larger trend. They could be rarer than the fossil record suggests, and not as applicable to hadrosaurs as a group, much less all herbivorous dinosaurs. That said, they don’t have to be a stable of dinosaur diets to be relevant, since not every expectant mother faces cravings and nutritional deficiencies either. With the amount of variation in diets and individual metabolisms we see in organisms today, it might actually be weirder if hadrosaurs never ate a crayfish or bug at any point in history.

Source: Big herbivorous dinosaurs ate crustaceans as a side dish by Jim Scott, Phys.org

On September 7th, 2017 we learned about

Dinosaurs’ methods for maintaining the temperatures needed to incubate their eggs

In 2015, paleontologists announced the discovery of Ugrunaaluk kuukpikensis, a 30-foot-long hadrosaur found in what would have been the arctic circle of the Cretaceous period. The large plant-eater hinted at many aspects of its era’s ecology, but one question that’s still being studied is how these creatures took care of their eggs. In a climate that averaged around 43° Fahrenheit, a bulky body could probably insulate itself sufficiently, but that wouldn’t have helped eggs too fragile to sit on.

Found under feathers

Researchers from the University of Calgary have been looking into these questions, surveying fossilized nests from around the world. The most obvious nesting behaviors have the clearest connections to today— feathered birds as modern dinosaurs use their body heat and feathered insulation to sit on their eggs to maintain the temperatures needed for incubation. Scientists are confident that many extinct dinosaurs did the same thing, as long as they had the feathers and size to make it work. Lighter-weight theropods, like oviraptors, have even been found on their eggs. Analysis of the oxygen isotopes in the fossilized eggshells and embryos point to the eggs being kept at around 104° Fahrenheit, well within reason for a doting parent’s body to provide.

Sizzling from the Sun

Of course, sitting on a nest wasn’t an option for all dinosaurs. Aside from possibly lacking the insulating feathers of theropods, many animals were just too big to put their weight on their eggs. For these creatures, researchers have considered other modern relatives of dinosaurs, specifically crocodiles. Crocodiles, and some birds, can take advantage of their warmer climates to capture a lot of warmth from the Sun.  They bury their eggs in a mound of sandy dirt to insulate the eggs, presumably trapping more heat than they block in the process. Eggs of especially large dinosaurs, like the long-necked sauropods, turn up in soils that would be a good match for this kind of incubation.

Cooked under compost

When the sunshine might not be consistent, dinosaurs probably had other strategies to rely on. Like modern malleefowl, some species maybe buried their eggs in more than just dirt, adding layers of plant material into the mix. As those plants decomposed, the microbes eating them would release heat, and that heat could be sufficient to keep buried eggs warm, even in colder climates. Nests from hadrosaurs, like U. kuukpikensis, have been found to have a fair amount of plant material fossilized with other soil. With a good supply of rotting leaves, this method probably got a lot of dinosaurs through their extended gestation, even up north.

For as compelling as the above examples are, they’re not definitive. Even dinosaur eggs were fragile, and so there aren’t a lot of examples to study and confirm exactly how widespread the above nesting techniques really were. It’s possible that dinosaurs had other methods to care for their unborn eggs, although we have yet to find evidence of more radical adaptations, like live birth that lets a mother skip nest building altogether. For now, we can only speculate on if Nanuqsaurus hoglundi ever followed one of the more famous forms of incubation in the cold, carrying its eggs on its clawed toes for months at a time like a penguin.

Source: How did dinosaur eggs survive in the Arctic? by David Moscato, Earth Touch News Network

On September 4th, 2017 we learned about

Fossilized footprints found near Crete may seriously complicate our ancestors’ origins

Your foot may ache, smell and maybe need a toenail trim, but it’s a pretty special bit of anatomy. Even if you’re used to your single row of clawless of toes, it’s actually a unique arrangement among just about every animal on Earth. Our closest living relatives don’t have their hallux, or big toe, facing forward like we do, giving them a much more hand-shaped foot. These toes, along with the ball of our foot and long instep, come together to make a very distinct footprint. What’s exciting scientists now is that some of these prints have turned up in a time and place where they supposedly had no business being.

A set of footprints were found hardened into sedimentary rock on an island called Trachilos, off the coast of Crete. Based on the foraminifera, or marine microfossils, found in the layers of rock above and below the slab of stone in question, researchers confidently dated the prints as being 5.6 million years old. The catch is that at that time, no human ancestors, much less humans, were thought to be anywhere but Africa. What’s more, the shape of the prints look more like modern feet than any known ancestor living at that time.

Figuring out the who, what and where

Even without an actual bone or tool, these footprints may be enough to up-end our timeline for human evolution. The oldest confirmed hominid is Ardipithecus ramidus, who is thought to be a direct ancestor to modern humans. However, A. ramidus lived in Ethiopia around 4.4 million years ago, and at that point had a much more gorilla-shaped foot. We know that by 3.65 millions ago, our ancestor Australopithecus was leaving very modern-looking footprints in Tanzania, but neither of these dates sync up with the stroll some primate took through Crete at least a million years earlier.

Putting the evolutionary questions about foot-shapes aside, walking to the island of Trachilos is actually one of the easier issues to understand. North Africa and the Mediterrean Sea were very different places 5.6 million years ago, as the Sahara Desert was a savannah and the Mediterrean was beginning to dry up, thanks to the Strait of Gibraltar closing off the waters of the Atlantic Ocean. What’s more, Crete itself was still attached to the Greek mainland, making access to this particular plot of land all the more plausible.

Many questions to consider

Assuming this initial interpretation of these 50 footprints hold up, anthropologists have a lot of new questions to explore. Were the prints made by a hominid, or just a very similar gorilla living in Europe? Did this mystery primate walk out of Africa to Trachilos, having evolved our unique feet earlier than anyone thought? Were these prints left by a direct relative to modern Homo sapiens, or is this an offshoot of our family tree that didn’t end up succeeding with their early upright gait? Or, most radically, did our ancestors originate outside of Africa, strolling south instead of north? That last idea is a long-shot, and would still leave the species Homo sapiens as originating in Africa, but this simple stroll in the soft soil now demands that we investigate a lot of new possibilities.

My third grader said: I hope it turns out to be one of the crazier explanations!

Source: What Made These Footprints 5.7 Million Years Ago? by Gemma Tarlach, Dead Things

On September 3rd, 2017 we learned about

Simulating the stresses that make single-toed horse feet make sense

Farriers would have had a much more difficult job 55 million year ago. Making a modern horseshoe isn’t necessarily easy, but the famous “U” shape is a lot simpler than what an ancient horse’s four- and three-toed feet would have needed. Of course, ancient animals like Hyracotherium probably wouldn’t have required a metal shoe in the first place. They were much smaller animals that scurried through tropical forests on feet that looked a lot like your average dog’s, give or take a toe. That obviously changed over time, and while scientists are confident about the course of change that created modern one-toed horses, zebras and donkeys, they’ve had a much harder time understanding how these changes provided much of an advantage over retaining more digits.

Where to put the weight

To dig into potential biomechanical advantages of the modern horse hoof, researchers made detailed scans of fossils and bones to really understand the structure of each species’ legs. More ancient animals, like Hyracotherium, were only 20 pounds. Nonetheless, their weight was distributed over multiple digits on each foot, with each digit ending in a small hoof. This arrangement was similar to a modern tapir, and meant that no single toe had to bear too much stress with each step.

Over time, the central toe took on bigger and bigger role. In Pseudhipparion, a horse ancestor that lived in the Miocene epoch, the middle toe was found to hold up to the stresses of running as much as a foot with every toe pitching in equally.  As species continued to grow larger and larger, the central toe seemed to become more and more robust to handle the load. We sometimes put shoes on horses today, but a healthy hoof, combined with thicker, slightly hollowed leg bones, can handle a lot of stress without a problem.

Dropping unneeded digits

With a center toe taking so much weight successfully, the other digits on horses foot may have simply become dead weight. Once horses moved out of forests and began specializing in running through open spaces like grassy plains, their legs grew longer and speed became a bigger issue. Extra toes may not seem like a big deal, but if they’re not really being used, they’re essentially just more tissue requiring energy to grow, keep healthy, and move around. With a center digit strong enough to hold their weight, it seems that horses just didn’t gain anything from keeping their other toes, and so evolution purged them over time.

My third grader asked: So all the one-toed animals are horses, zebras and donkeys? Cows and gazelles aren’t related?

This evolutionary path has only been followed by members of Equidae, which is today represented by horses, zebras and donkeys. While cows and gazelles have hard hooves, they are actually more distantly related to horses than tapirs and rhinos. The fact that so few animals have abandoned nearly all of their digits is part of why scientists have been so curious about equids’ unusual feet.

Source: How the horse became the only living animal with a single toe by Nicola Davis, The Guardian

On August 31st, 2017 we learned about

Three oviraptor siblings have been snuggled together since the Cretaceous

70 million years ago, three oviraptors bedded down for the last time, possibly dying together in their sleep. Since then, they’ve managed to rest in relative piece (sorry!) as two of the threes’  skeletons are mostly intact. It’s not the first time we’ve found evidence of oviraptors on nests, but these three don’t seem to have been guarding any eggs. They were likely siblings, and spent their final moments trying to guard each other.

When fossils are found in proximity to each other, paleontologists have to be careful about assuming they were together temporally. In this case, however, the bones and arrangement of the skeletons strongly implies that the three theropod dinosaurs were once in direct contact with each other, right down to one specimen curving its body to push against its neighbor. The fact that these postures aren’t the classic death pose, but instead matches the communal roosting of living species like crows, right down to their heads being tucked over their backs, further supports the notion that these three curled up together on purpose.

Animals don’t normally pile up with strangers at random. Because these three dinosaurs all show similar bone growth and developmental maturity, such as matching but immature head crests, scientists believe there’s a good chance they were all siblings, probably in adolescence. Again, this echos the behavior of living birds, such as ravens that stay near their family, even as they’re old enough to feasibly survive on their own.

Motivations in their final moments

With all of this evidence suggesting the three oviraptors were snuggling up together intentionally, we can sadly only speculate about their motivation for doing so. One hypothesis is that they were trying to protect themselves from a sandstorm. This would help explain their deaths and well-protected burial, but it they somehow seem too tranquil for a demise involving high winds. There’s a chance they were sleeping due to the similarity of their poses to some birds, but that doesn’t really explain why they never woke up. However, if they were trying to stay warm together to try and survive extreme cold, then this final snuggle-session fits together pretty well. It would also support other evidence about some dinosaurs being warm-blooded, as the warmth they’d have been trying to preserve would have been coming from their bodies.

My third grader asked: Exactly how old were they?

They were estimated at being two to five years old, and probably weighed close to 100 pounds each. At this age, they probably stuck together as a group to not compete with adults, but also not be totally left on their own.

Source: Dinosaur trio roosted together like birds by Traci Watson, Nature

On August 24th, 2017 we learned about

Tanzanian titanosaur appears to have been trapped by Africa’s slow split from South America

Shingopana songwensis was a bit of a misfit. The newly described titanosaur, a subset of long-necked sauropod dinosaurs like Apatosaurus, didn’t check all of the boxes some of it’s more famous relatives did. S. songwensis was not mind-bogglingly large like Patagotitan mayorum, weighing in at only five tons instead of 69. It didn’t have the cool armored scales found on titanosaurs like Rapetosaurus krauseiIn fact, analysis of S. songwensis‘ anatomy suggests that the lumbering creature didn’t even live near it’s own relatives, having been trapped on the wrong side of the growing Atlantic ocean over 70 million years ago.

Titanosaurs were found all over the world, having once had the opportunity to walk everywhere. When the world’s land masses were joined in one large supercontinent called Pangea, the southern mass of land called Gondwana included what is now South America, Africa, Australia and Antarctica. This allowed animals like dinosaurs to roam and proliferate near and far, at least until the land masses started to break up in the Jurassic period, around 184 million years ago. At that point, animals like the titanosaurs were split by geography into smaller groups, eventually leading to new, separate species and traits specific to particular lineages.

Regional resemblances

Most of the titanosaur fossils we’ve found have come from South America, but there have been discoveries of these long-necked herbivores in South America, Australia, Africa and Antarctica as well. Each region has it’s own identifying traits thanks to their geographic separation, except S. songwensis stands out because it has the wrong traits for its region. Instead of looking like other African titanosaurs, it looks more like a visitor from South America, with researchers going as far as saying it looked like a sibling to South American titanosaurs, but only a cousin to it’s closer African neighbors.

The best explanation is that S. songwensis was somehow isolated in South Africa, away from the titanosaurs living in North Africa at the same time. While some creatures did partake in rafting to move between South America and AfricaS. songwensis seems to have simply been trapped in it’s own geographic, and thus genetic, pocket, somehow holding on to traits it’s ancestors brought out of South America. This would fit with the fact that South Africa separated from South America before North Africa did, with the Atlantic Ocean expanding from the south toward the north. The isolation was probably reinforced by other climate or geographic features, keeping these orca-sized titanosaurs away from more closely related family members.

Source: Paleontologists discover new species of sauropod dinosaur in Tanzania, National Science Foundation