The "Dragon Man" Skull was Probably a Denisovan

Back in 2021, Chinese paleontologists published a skull from an archaic human, dated to around 146,000 years ago, that they attributed to a new species. They called this species Homo longi, Dragon Man, since it was supposed to have been found along the Dragon River.

But Qiaomei Fu, a geneticist who played a part in identifying Homo denisova, had his suspicions that this was really a Denisovan. He eventually got the chance to study the skull. First attempts did not identify any DNA but they did produce some protein sequences that matched Denisovan sequences from the famous finger bone. Then, anayzing some dental calculus, they found mitochondrial DNA that closely matches Denisovan DNA.

There are a lot of caveats to be made here, in particular that we're talking about DNA snippets rather than long strands, and we already know that there was human diversity and interbreeding in East Asia in that period. But this looks pretty good to me, so the digital model you see in these two images may well be the cranium of a Denisovan.

Incidentally, I learned from the Cell article that the current consensus is that Neanderthals and Denisovans diverged around 400,000 years ago.

Denisovans in Southeast Asia

Major paper in Nature this week summarizing what we have learned about ancient Denisovans from a pathetic pile of fossils and extensive genetic research. (NY Times; good summary article about Denisovans at Britannica)

The first discoveries, made at Denisova Cave in Siberia, showed that Denisovans had been around from, at minimum, 150,000 to 75,000 years ago; that they interbred with Neanderthals; and that some of their genes seemed to be present in modern East Asian humans. Other likely Denisovan bone fragments have now been found in Tibet and Laos.

More recent genetic studies suggest further intermixing with modern humans in Southeast Asia, perhaps as recently as 25,000 years ago. The Denisovan signature seems to be particularly strong in some groups in New Guinea and the Philippines. This may mean that they were able to thrive in both Siberia and tropical southeast Asia, giving them one over Neanderthals, who have not been found outside Ice Age climes.

I caution that all of this is very new and rather speculative; I am especially skeptical of DNA found in soil rather than bones. But it truly is remarkable that modern genetics has allowed us to conjure up a lost branch of humanity from a few shards of bone.

Hațeg Island's Mini Dinosaurs

I can't believe that I just yesterday learned about Hațeg Island and its small dinosaurs.

Hațeg Island was a large offshore island in the Tethys Sea, that is, the ancient sea betwen Europe, Asia, and Africa, more or less where the Mediterranean and Black Seas are today. It existed during the Late Cretaceous period, probably from around 100 to 66 million years ago. Rocks from this island were discovered near modern-day Hațeg, Romania. The island was lifted by the same mountain-building episode that gave us the Balkans and the Anatolian highlands. Wikipedia suggests that Hainan Island, off the southern coast of China, is a good comparison in terms of size, topography, and climate.

The fascinating thing about Hațeg Island is that the patterns of animal life we know from modern islands were present there in distorted, dinosaur-age form. For example, most terrestrial animals were smaller than their mainland forms. Above are a skeleton of an Inguanadon of the genus Zalmoxes, named after a Thracian god about whom Herodotus told stories of human sacrifice, and a diagram showing how much smaller it was (in purple) than most other Iguanadons. The diagram at the top of the post compares Zalmoxes robustus, from Hațeg, to the next smallest known species.

Here's a Titanosaur from Hațeg called Magyarosaurus. Most Titanosaurs were gigantic beasts, but this one was horse-sized. (The grid is 1-meter squares).

But while many species shrank on the island, the opposite also happened. Just as some islands came to be inhabited by huge flightless birds, Hațeg was home to gigantic pterosaurs. This is Hatzegopteryx, probably the dominant predator on the island. Only very partial fossil remains have been found, so it is unclear whether Hatzegopteryx could fly. But it certainly didn't need to.

Icaronycteris gunnelli and the Evolution of Bats

A wonderful fossil from the Green River formation in Wyoming has been identified as a new species of bat, Icaronycteris gunnelli. It dates to around 52 million years ago, making it the oldest bat fossil yet identified. This was a small animal, weighing less than an ounce (25 grams), roughly the size of a modern little brown bat.

The Green River Formation is the remains of three huge lakes that once covered parts of Utah, Wyoming, and Colorado. They endured for around 12 million years, which is a long time for lakes, gradually accummulating sediment and preserving many wonderful fossils. The Green River formation spreads across around 65,000 square kilometers or 25,000 square miles and reaches 600 meters (2,000 feet) in thickness. Which is a lot of rock.

The remains of Fossil Lake have proved (no surprise) to be particularly rich in fossils; this slab shows two small fish, a snail, and a bird.

The formation looks like this; much of it is exposed in canyon walls along the Green River, hence the name.

The Field Museum has a delightful slide show of specimens from Fossil Lake.

This small carnivorous mammal has the first known prehensille tail, and in fact its tail has more verterbrae than any other known species.

But to get back to bats! This one is from wikipedia, found in 2021 and not yet identified.

Paleontologists are avidly pursuing ever older bat fossils because their evolution remains a complete mystery. We have made much progress in recent decades understanding other evolutionary puzzles, such as the evolution of whales, birds, and turtles. But so far there are no transitional fossils for bats. They just pop up in the record 50 million years ago, fully formed. By 50 mya they are also distributed around the world, with some fine fossils from India. So nobody knows where they arose, either. All we can say with certainty is that they were part of the great explosion of mammals that took place after the dinosaurs were wiped out 65 million years ago.

But it would be boring if we understood everything, right? 

Miocene Fossils from McGraths Flat, Australia

Amazing fossils from 15 million-year-old deposits in Australia, preserved in iron-rich rocks. 

The exquisite details include feathers, tiny parasites riding on larger organisms, even pollen grains. 

This spot seems to have been an Oxbow Lake in a rain forest ecosystem. As to how this happened, the excavators are not sure:

The secret to the fossils’ preservation is up for debate, but McCurry thinks it would have happened over hundreds of years rather than in a sudden event.

Iron-rich water, maybe from nearby outcrops, could have flowed into a shallow billabong, periodically deoxygenating the water, killing the organisms or encasing flora and fauna in sediment that turns into the rocks found in the field.

Close-up of the sawfly above, showing its head, and a microscopic image showing the pollen grains still visible there. Astonishing.

A larval mussel riding on the fin of a fish as a parasite.

Tiny flowers.

Longhorn Beetle. Original publication, long story at the NY Times.

Meet Stan

Tyrannosaurus Rex skeleton from South Dakota, 67 million years old, to be auctioned off by Christie's on October 6. Most likely it will end up in a museum whoever buys it, because even for a billionaire mounting and maintaining a fossil like this would be quite a burden.

From Christie's Online Auction of Rocks and Fossils

Triceratops porsus skull, 68-65 million years old. Estimate £150,000 - £250,000

Extraterrestrial peridot, from the Admire meteorite.

Bison antiquus, c 15,000 years old; this is the native North American bison that went extinct at the end of the Pleistocene, to be replaced by Bison bison.

Bicolor cubic fluorite.

Palm leaves with fish, Eocene, c. 50 million years old. A "composite" formed by placing the fossil fish onto a different layer of the rock with the palm leaf in it. So all real fossils, but arranged by human hands. I wonder what the people who do this call themselves. Fossil artists?

Gogotte, which according to this site 

are formed from quartz crystals and calcium carbonate. They were produced when superheated water extruded through crevices into a basin of extremely fine white silicate sand. The water was saturated with calcium carbonate (Limestone). The swirls and eddies of the water were captured in the gradually concreting stone, forming the most wonderful natural sculptures.

Large ammonite, Jurassic, 2 feet (60 cm) across. Much more here.

Denisovan Jawbone Found in Tibet

Behold the largest fossil yet found from the ancient humans we call Denisovans after the Siberian cave where their first fossils were found. Where, in fact, all the Denisovan fossils until this one had been found. We knew Denisovans had to be a widespread species, though, because they interbred with both Neanderthals and modern humans; in fact most of what we knew about them came from studying their genes. Not just the partial genomes extracted from fossils, mind you, since some insights have come from pondering what the Denisovans genes in modern humans seem to do.

It's quite odd, really, that we have discovered (or possibly imagined) so much about these people with no fossil record beyond a toe bone and some fragments. This one jaw increases our knowledge of Denisovan bones tenfold. It was found in Tibet back in 1980 and has been sitting on a museum shelf ever since, paleontologists occasionally wondering what it might be but not coming to any conclusions. It dates to about 160,000 years ago.

As to why Chinese paleontologists think this jawbone is Denisovan, well, that is a tale. Pondering this ancient jaw, which doesn't seem to belong to any known species but isn't all that old as these things go, they at first tried to extract DNA. No luck. So they tried again with proteins, eventually extracting and isolating collagen proteins that could be sequenced. The sequence is clearly not from a modern human, and it matches more closely to those from Denisovan bones than those from Neanderthals.

It's impressive work but this is a new technology and far from certain. Still, that jawbone has to be something, and if it isn't Denisovan then there was yet another human species wondering around out there.

And then there's this:

The altitude of the new Denisovan’s home — 3,280 metres above sea level — surprised researchers, and helps to solve a mystery about Denisovans’ genetic contribution to modern Tibetans. Some Tibetans have a variant of a gene called EPAS1 that reduces the amount of the oxygen-carrying protein haemoglobin in their blood, enabling them to live at high altitudes with low oxygen levels. Researchers had thought that this adaptation came from Denisovans, but this was difficult to reconcile with Denisova Cave’s relatively low altitude of 700 metres. The latest study suggests that Denisovans evolved the adaptation on the Tibetan Plateau and passed it to Homo sapiens when the species arrived around 30,000–40,000 years ago.

Don't ask my why having less haemoglobin helps you survive with less oxygen, but wikipedia's article about EPAS1 says the same thing, so there it is.

The Day the Dinosaurs Died?

Fascinating fossil discovery in North Dakota, piles of fossils in what had been a freshwater pond but was somehow overwhelmed by water from the sea and then clogged with sediment in one catastrophic event. The picture above shows the jumble of fish fossils that characterize the site. This may (emphasis on the "may") be the signature of the asteroid impact that ended the Cretaceous Period and with it the dinosaurs and many other animal species:

In the deposit, the team discovered an ancient freshwater pond whose occupants had been quickly cemented together by waves of sediment and debris. The fossils include sturgeon and six-foot-long paddlefish, their scales intact but their bodies ripped and smashed; marine mollusks; leaves and tree fronds, and the burned trunks of trees. The fish carcasses were not bloated, decayed, or scavenged, suggesting that they were buried quickly — and that few animals were left alive after the cataclysm to come digging.

The fossil deposit also teems with tektites, tiny glass beads that are the telltale fallout of planetary-scale impacts. Fifty percent of the fossilized fish were found with tektites in their gills, as if the fish had inhaled the material. Also recovered were tektites trapped in amber. Their chemical composition was unchanged in 66 million years, and it closely matched the unique chemical signature of other tektites associated with the Chicxulub event.

The top layer of the fossil bed was found to be rich in iridium, a rare metal that Dr. Alvarez had originally identified at other sites as arising from the giant object that struck the Earth. Iridium, a precious metal belonging to the platinum group of elements, is more abundant in meteorites than in terrestrial rocks.

The excavators, led by Robert DePalma, theorize that the pond was drowned by the great tsunami that spread out from the asteroid impact site, and then filled by debris raining from the sky.

Amazing.

A Frog Trapped in Amber

99 million years old.

Little Foot

"Little Foot" is what the discoverers call an amazing, largely intact skeleton of an Australopithecus found in South Africa. Now a new dating technique suggests that it may be 3.6 million years old, about half a million years older than "Lucy". National Geographic:

Previous attempts to date Little Foot have yielded highly uncertain results, ranging from 2.2 million years to over 4 million years old. The dating technique used in the new study, called isochron burial dating, calculates the age of a specimen based on when it was last on the surface, exposed to cosmic radiation that produces radioactive isotopes of the elements aluminium and beryllium. When the sediments washed into the cave, the isotopes stopped accumulating, and instead begin to decay at a steady rate. Nine out of eleven samples from rock surrounding the skeleton gave an age of 3.67 million years.

I think paleontologists spend too much time an energy fighting over which fossil was first and which species they belong to. The long-running South vs. East Africa debate is irritating and probably unresolvable. But the ever-growing number of old human and human-like fossils is fascinating, and the diversity of their shapes shows evolution in action in a compelling way. The broad distribution of Australopithecus afarensis is also interesting, since fossils have now been reported from South Africa to Chad. This was not a shy, rare species, but a very successful one that used its slightly-smarter-than-a-chimp brainpower and upright posture to spread across the continent, hinting at the future dominance of its lineage.

Two Hundred Pterosaur Eggs

Amazing find from China:

The species that laid the recently discovered eggs is known as Hamipterus tianshanensis. It lived during the early Cretaceous period and its wings stretched about 11 feet long. It also sported a thick forehead crest and had a mouth full of pointy teeth for snatching fish.

Xiaolin Wang, a paleontologist at the University of Chinese Academy of Sciences, Beijing, and lead author of the study, discovered the eggs in a 120-million-year-old pterosaur boneyard in the arid Gobi Desert in northwestern China. When the pterosaurs thrived, the place was most likely a lush lakeshore. The team suggested that a strong storm most likely washed the eggs into the lake, where they were buried alongside pterosaur bones and preserved for millions of years.

This is strong evidence that these pterosaurs nested in big colonies like some modern seabirds.

How Dinosaurs Lost their Teeth

For me the big obstacle to imaging birds as dinosaurs has always been teeth: dinosaurs had them, birds don't. But this is another part of paleontology that is more complex than the simple version, because most early birds had teeth and some non-bird dinosaurs had beaks. And now there is some good new science about how the transition took place:

Using fossils and a large comparative analysis of modern animals, Dr. Balanoff and a team of evolutionary biologists, led by Shuo Wang from the Capital Normal University in Beijing, found that the loss of teeth and the emergence of beaks are connected processes in theropods. As the beak grew across the dinosaur’s face, it also inhibited the growth of teeth, the team suggested. On an evolutionary scale this transition happened until theropods developed mouths that resembled the bird beaks seen today.

In earlier research, Dr. Wang’s team discovered an emu-like theropod called Limusaurus that began life as a baby with teeth, but lost them as it grew older and morphed into an adult with a beak. [above]

For their most recent paper, he and his colleagues examined more dinosaur jaw fossils and found two other theropods that underwent transitions similar to Limusaurus: an early Cretaceous bird called Sapeornis, which resembled modern birds, and a small caenagnathid oviraptorosaur, which resembled a velociraptor but with a beak.

“This demonstrates an evolutionary process of the beak for the first time,” said Dr. Wang.

All three of these dinosaurs had beaks with vestigial tooth sockets, as in the Sapeornis jaw above.

When paleontologists look closely at any change in the fossil record that seems like a dramatic break, they find lots of intermediate cases and strange branchings and evidence that the change took place in different ways in different groups and so on: in other words, a disorderly mess. Evolution is like that. Birds once seemed different from dinosaurs in both having feathers and having beaks. Now we know that lots of dinosaurs had feathers, including most if not all theropods, and from fossils in amber and mudstone and we have learned a lot about how many different sorts of feathers they had and begun to understand how they evolved. We are just in the early stages of understanding beaks, but already enough is known to show that they evolved in several different lineages of dinosaurs.

Gliding Mammals of the Dinosaur Age

Among the many spectacular mammal fossils that have emerged from Jurassic quarries in northeastern China are some that resemble modern flying squirrels. These include Maiopatagium, above;

and Vilevoledon. Both about 170 million years old. These are not placental mammals, so they are not related to flying squirrels; just another case of convergent evolution.

There were no flowering plants yet, so no fruit; perhaps they fed on conifer seeds.

These gliding animals are a good example of the great diversity of mammals that lived in Jurassic times, something we knew nothing about until the 1990s. Besides gliders, Chinese paleontologists have also found mammals that swam like otters and mammals with claws like those anteaters use to pull open insect mounds.

Baby Bird in Amber, 105 to 95 Miliion Years Old

Amazing discovery.

Feather details.

Foot.