T-Rex Was Warm Blooded

A new study of a T-Rex tooth has determined that these dinosaurs were warm blooded, unlike almost all reptiles today (except leatherback sea turtles and Argentine black and white tegus), but like modern birds, which are the sole surviving branch of dinosaurs.

Despite an extensive history of study, quantitative constraints on the thermophysiology of Tyrannosaurus rex remain limited. Here, we derive a thermodynamically based determination of T. rex body temperatures from clumped isotopes in tooth enamel. Measurements of three T. rex teeth from the Late Cretaceous Hell Creek Formation yield a temperature of 36.3 ± 2.5°C (1 SE), comparable to modern endotherms. Teeth of coeval Hell Creek Formation crocodilians yielded temperatures significantly lower than did those of T. rex. Comparison with proxy-derived paleotemperatures and model simulations indicates that T. rex maintained a higher body temperature than its environment. Projected habitat suitability for T. rex based on these results shows that most of the North American paleocontinent, including colder and higher latitudes, were potentially accessible to the species.

Randon J. Flores, "The body temperature of Tyrannosaurus rex" 12(38) Science Advances (September 16, 2026) DOI: 10.1126/sciadv.aeb7653.

Astronomy Meets Climate

A 100,000 year climate cycle on Earth can be explained by Earth's orbit.

The 100,000-year problem concerns the dominant period of glacial-interglacial cycles over the past 800,000 years and their correlation with Earth's orbital eccentricity, despite eccentricity's weak influence on solar radiation. 

Two theories compete: the astronomical theory, in which orbital forcing drives the cycles with amplification from Earth system feedbacks, and the geochemical theory, in which internal dynamics dominate with orbital forcing synchronising oscillations. We investigate these theories using conceptual models. 

Augmentations to the Budyko energy balance model fail to reproduce the 100,000-year period, revealing formulation limitations. Linearised versions of existing non-linear ice volume models perform comparably to their full counterparts, indicating the data does not necessitate non-linear dynamics. We develop two simple linear models: a feedforward model aligned with the astronomical theory and a feedback model aligned with the geochemical theory. 

The feedforward model reproduces the ice volume record well and offers a novel explanation for the absence of eccentricity's 400,000-year period, arising from oceanic heat storage and tropospheric energy responding with differing phase lags. Conservative estimates show bulk ocean temperature variation can be explained by eccentricity alone, challenging the geochemical theory's core assumption. 

We also show that widespread use of Q65 may bias models towards geochemical explanations by underrepresenting eccentricity. The feedback model's improvement is concentrated around Marine Isotope Stage 11, suggesting this anomalous interglacial reflects Earth-based events rather than a general requirement for feedback mechanisms. We conclude that 800,000 years of glacial cycles can be largely reproduced by a linear astronomical model, emphasising the importance of parsimony when interpreting palaeoclimate data.

Liam Wheen, "A First Principles Approach to the 100,000-year Problem" arXiv:2604.12143 (April 14, 2026).

Quick Hits

* The Sumerians had different number words and symbols to count numbers of different kinds of things. So, for example, the word for five pieces of fruit would be different than the word for five logs.

* Egyptian pyramids were built as trapezoids and then cut down to pyramids with the left over rock used to make new pyramids.

* Reputedly, Emperor Basil II of the Byzantine Empire was cruel.

* The Anglo-Saxons kept slaves in the middle ages.

* According to Gerald of Wales ca. 1316 CE, at that time the Irish were predominantly herders.

* Harsh murder sentences for newborns killed or neglected in the throes of unattended child birth are still common today even though the death penalty is almost never sought now in these circumstances.

* The TYRP1 gene variant discovered in 2012, is the cause of blond hair in the Solomon Islands in Melanesia, which is a different gene than the one that causes blond hair in Europeans.

* Before 1480, India and Sri Lanka were nearly connected by a land bridge known as Adam’s Bridge.

* There were once oceans on Mars.

High-resolution orbital images of Mars' largest canyon reveal ancient river deltas, proving the Red Planet once held an ocean the size of Earth's Arctic.

New high-resolution imagery from the European Space Agency’s ExoMars Trace Gas Orbiter has provided the most definitive evidence to date that Mars was once a blue planet. Researchers at the University of Bern identified distinct fan-shaped sediment deposits in the southeast Coprates Chasma region, part of the massive Valles Marineris canyon system. These structures, remarkably similar to river deltas on Earth, all sit at a consistent elevation between 3,650 and 3,750 meters. This geological alignment points to one unmistakable conclusion: the presence of an ancient coastline where rivers once emptied into a vast, stable sea approximately 3.37 billion years ago.

While previous theories about Martian oceans relied on lower-resolution data, this study offers direct geomorphological proof of a shoreline. The findings suggest that a massive body of water, comparable in size to Earth’s Arctic Ocean, once covered the entirety of Mars’ northern hemisphere. Though today these ancient deltas are buried beneath wind-sculpted dust and dunes, their distinctive shapes remain preserved. This discovery drastically alters our view of Martian history; the existence of a planet-wide water cycle and a stable ocean suggests that the conditions necessary for life were not isolated occurrences but a global phenomenon.

Source: Argadestya, P., et al. "Geomorphological and sedimentological evidence of a coastline in Southeast Coprates Chasma." npj Space Exploration (2026).

* There are social octopi that build homes for themselves off the coast of Australia.

* This very little bugger ,who is part of this clade of animals (and more specifically this one) is kind of cute in a Disney monsters way. They are the most heat-tolerant complex animal known to science after tardigrades (or water bears), which are able to survive temperatures over 150 °C. They were discovered in 1980 off the Galapagos islands.

When they grow up, they look like this (the "fur" is a symbiotic species of bacteria):

* A photograph of the February 19, 2026 solar eclipse in Antarctica (not AI).

* Nature can be amazing (also not AI).

* In West Texas, ca. 4500 BCE, hunter-gatherers used non-returnable boomerang sticks for small game and atlatl to throw their carefully crafted spears further for big game.

A cache of ancient weapons, more than 6,000 years old, has been uncovered in a remote rock shelter in West Texas, offering one of the clearest pictures yet of early life in North America.

The discovery was made at the San Esteban rock shelter in the Big Bend region, an area known for its dry climate and rugged desert landscape. That dryness turned out to be a gift to archaeologists. Items that would normally rot away wood, leather bindings, plant fibers remained intact for thousands of years. Inside the shelter, researchers found a carefully stored hunting kit dating to around 4,500 B.C., including wooden spear shafts wrapped in leather, stone projectile points, and parts of atlatls, the spear-throwing tools that dramatically increased a hunter’s range and power.

An atlatl works like a lever, giving a thrown spear greater speed and force. With it, hunters could strike animals from distances that would otherwise be impossible with a simple hand throw. Tests and prior studies show these tools could send projectiles well over 100 feet with deadly accuracy. The craftsmanship seen in the newly uncovered pieces shows careful shaping, balance, and planning. These were not rough survival tools; they were refined hunting systems built by people who deeply understood their environment.

Researchers also identified curved wooden throwing weapons often described as straight or non-returning boomerangs. Unlike the returning boomerangs many people picture today, these were designed to fly straight and hit small game with strong impact. Their presence adds another layer to what appears to have been a well-organized toolkit, likely stored together for repeated use.

The San Esteban site has a long history of human occupation stretching back thousands of years. Findings from this latest excavation reinforce the idea that the Big Bend region was not a temporary stop for wandering groups but a place where people lived, adapted, and developed sophisticated survival strategies. The tools show planning, skill, and an ability to work with available materials in smart, efficient ways.

Archaeologists involved in the project say the discovery helps rewrite outdated ideas about early North American societies. These communities were not primitive in the way older textbooks sometimes suggested. They engineered effective hunting technology, understood animal behavior, and created tools built to last.

As research continues, scientists hope to learn more about how these weapons were used, how they were stored, and what they reveal about daily life 6,000 years ago. For now, the dry rock shelter in West Texas has delivered something rare: a direct, tangible connection to hunters who once stood in the same desert landscape, preparing their tools for the next expedition.

* Maize farmers in Peru’s Chincha Valley were fertilizing their crops with seabird poop as early as the year 1250 CE.

* According to this source:

Around 3,800 years ago, a magnitude-9.5 megaquake struck northern Chile's coast, creating the largest earthquake known in human history. The rupture extended roughly 620 miles along the fault line—longer than the devastating 1960 Valdivia earthquake—and generated tsunamis with waves reaching 66 feet that traveled 5,000 miles across the Pacific Ocean to New Zealand. Archaeologists discovered marine deposits, boulders, shells, and sea life displaced far inland in the Atacama Desert, along with toppled stone structures buried beneath tsunami sediment, all radiocarbon-dated to this single catastrophic event.

The disaster forced complete coastal abandonment. Communities that depended on the ocean for survival relocated inland, staying away from the coast for over 1,000 years—an extraordinary response that demonstrates the quake's devastating impact on human populations. Researchers now recognize this megathrust earthquake, caused when tectonic plates suddenly unlocked after building massive strain, as both the oldest discovered earthquake-tsunami disaster in the Southern Hemisphere and a critical warning for modern coastal populations across the Pacific.

* Every recorded earthquake worldwide, 2015 to 2025 (my source didn't cite a source).

 

The Amazon Is Older Than The Andes

 The fascinating deep history of the Amazon River.

Fairies And Fungi

* Fairy rings are a fungal phenomena.

* Fairies are often depicted as chthonic with underground halls, and eating fairy food traps you in their world forever. Fungi are one of the few living things that can survive and thrive underground without light.

* The Santa Claus myth and Christmas tree ornaments are deeply tied to hallucinogenic mushroom use by shamans in places where reindeer roam.

* Fungi are pervasively present in temperate forests which are seen as a natural habitat of fairies and were places feared in medieval times.

* Fairies are associated with glamours and deception, and many fungi, such as ergot, cause hallucinations and a sense of distortion of time..

* Fungal infections can make insects and small plants look and behave weirdly in ways that could cause them to be called fairies.

* The bane of fairies, iron and to a lesser degree salt, are inorganic while fungi are organic.

* Curious children eating mushrooms that cause their death or cause them to act abnormally could be associated with the changling myth.

* Fungi come in many varieties that are hard to distinguish from each other like fungi.

* Fungi have properties that distinguish them from "normal" biological things like plants and animals.

* Could "fairy dust" be spores or yeast?

* Mushrooms are of a scale often associated with fairies.

* There is a forests, fairies, and fungi sticker book anthology.

* Fairies are often depicted as amoral or having fundamentally different motivations than humans, which is a fit to fungi and its effects on mankind.

How Long Do Animals Live?

 

The History And Prehistory Of Human Disease

A new paper in Nature concludes from ancient DNA that while infectious diseases were common in humans since the hunter-gatherer era, that there was a real surge, not at the time of the Neolithic Revolution, but when steppe herders started to invade and conquerer farmers, and hunter-gatherers, possibly because they lived more closely with their animals and because the diseases that they carried helped facilitate their conquests. The New York Times also discusses the paper.

Infectious diseases have had devastating effects on human populations throughout history, but important questions about their origins and past dynamics remain. To create an archaeogenetic-based spatiotemporal map of human pathogens, we screened shotgun-sequencing data from 1,313 ancient humans covering 37,000 years of Eurasian history. We demonstrate the widespread presence of ancient bacterial, viral and parasite DNA, identifying 5,486 individual hits against 492 species from 136 genera. Among those hits, 3,384 involve known human pathogens, many of which had not previously been identified in ancient human remains. Grouping the ancient microbial species according to their likely reservoir and type of transmission, we find that most groups are identified throughout the entire sampling period. Zoonotic pathogens are only detected from around 6,500 years ago, peaking roughly 5,000 years ago, coinciding with the widespread domestication of livestock. Our findings provide direct evidence that this lifestyle change resulted in an increased infectious disease burden. They also indicate that the spread of these pathogens increased substantially during subsequent millennia, coinciding with the pastoralist migrations from the Eurasian Steppe

Martin Sikora, et al., "The spatiotemporal distribution of human pathogens in ancient Eurasia" Nature (July 9, 2025).

Are Oxygen Levels Related To Earth's Magnetic Field?

The strength of Earth’s magnetic field seems to rise and fall in line with the abundance of oxygen in the planet’s atmosphere, a study of geological records spanning the past half a billion years has found.

From the journal Nature. 

Among other things, the overall oxygen levels in the atmosphere impacts how large animals get, with more oxygen favoring larger animals.

It isn't clear what causes drive the correlation, although there probably is a cause.

Why Do We Kiss?

Why do we kiss? Is there an evolutionary advantage to it? This article tries to answer that question.

A kiss has been a signal of special affection across continents and cultures for millennia. Between times and peoples, social norms invariably prescribe kissing to specific affiliations and contexts, implying deeper biological bases. Why the protruding of the lips and slight suction when touching another? 

Capuchin monkeys stick their fingers in their friends' eyes as sign of affection, why have humans developed kissing? 

Here I briefly review proposed hypotheses for the evolution of human kissing. Great ape social behavior suggests that kissing is likely the conserved final mouth-contact stage of a grooming bout when the groomer sucks with protruded lips the fur or skin of the groomed to latch on debris or a parasite. The hygienic relevance of grooming decreased over human evolution due to fur-loss, but shorter sessions would have predictably retained a final “kissing” stage, ultimately, remaining the only vestige of a once ritualistic behavior for signaling and strengthening social and kinship ties in an ancestral ape.

Adriano R. Lameira, "The evolutionary origin of human kissing" Evolutionary Anthropology (October 17, 2024) https://doi.org/10.1002/evan.22050

Birds Down Under

One of the earliest ever bird fossils has been found in Antarctica.

Fossils representing Cretaceous lineages of crown clade birds (Aves) are exceptionally rare but are crucial to elucidating major ecological shifts across early avian divergences. Among the earliest known putative crown birds is Vegavis iaai, a foot-propelled diver from the latest Cretaceous (69.2–68.4 million years ago) of Antarctica with controversial phylogenetic affinities. Initially recovered by phylogenetic analyses as a stem anatid (ducks and closely related species), Vegavis has since been recovered as a stem member of Anseriformes (waterfowl), or outside Aves altogether. 

Here we report a new, nearly complete skull of Vegavis that provides new insight into its feeding ecology and exhibits morphologies that support placement among waterfowl within crown-group birds. Vegavis has an avian beak (absence of teeth and reduced maxilla) and brain shape (hyperinflated cerebrum and ventrally shifted optic lobes). The temporal fossa is well excavated and expansive, indicating that this bird had hypertrophied jaw musculature. The beak is narrow and pointed, and the mandible lacks retroarticular processes. Together, these features comprise a feeding apparatus unlike that of any other known anseriform but like that of other extant birds that capture prey underwater (for example, grebes and loons). The Cretaceous occurrence of Vegavis, with a feeding ecology unique among known Galloanserae (waterfowl and landfowl), is further indication that the earliest anseriform divergences were marked by evolutionary experiments unrepresented in the extant diversity.

Christopher R. Torres, et al., "Cretaceous Antarctic bird skull elucidates early avian ecological diversity." 638(8049) Nature 146 (2025) DOI: 10.1038/s41586-024-08390-0

Hat tip to Science Daily which provides additional explanation in a somewhat less jargon heavy way. It begins by stating:

Sixty-six million years ago, at the end of the Cretaceous Period, an asteroid impact near the Yucatán Peninsula of Mexico triggered the extinction of all known non-bird dinosaurs. But for the early ancestors of today's waterfowl, surviving that mass extinction event was like…water off a duck's back. Location matters, as Antarctica may have served as a refuge, protected by its distance from the turmoil taking place elsewhere on the planet. Fossil evidence suggests a temperate climate with lush vegetation, possibly serving as an incubator for the earliest members of the group that now includes ducks and geese.

Dingo Origins

The dingo came from East Asia via Melanesia.

the new study, published in Nature Scientific Reports, uses sophisticated 3D scanning and geometric morphometrics on ancient dingo specimens to show clearly that they are most similar to Japanese dogs, as well as the 'singing dogs' of New Guinea and the highland wild dog of Irian Jaya.

The remains studied were over 3,000 years old. 

From this source, citing:

Koungoulos, L.G., Hulme-Beaman, A., Fillios, M. et al., "Phenotypic diversity in early Australian dingoes revealed by traditional and 3D geometric morphometric analysis." Sci Rep (2024) DOI: 10.1038/s41598-024-65729-3

Origin Of Dinosaur Killing Object Located

It is pretty stunning that this 66 million year old mystery can be solved at all. 

The key was the chemical composition of the impactor, which contained Ruthenium. This is almost completely absent on Earth apart from rare extraterrestrial impactors, and is also absent in other impactor candidates, including comets and "siliceous asteroids, a class that formed closer to the sun than carbonaceous asteroids and that are concentrated in the asteroid belt between Mars and Jupiter. Most meteorites that end up on Earth’s surface are from this siliceous family."

Unusual Origin Found for Asteroid That Killed the Dinosaurs

A study adds strong evidence to the hypothesis that the deadly rock came from a family of objects that originally formed well beyond the orbit of the planet Jupiter. . . .

The nature of this apocalyptic object, known as the Chicxulub impactor, has inspired intense debates, including a long-running dispute over whether it was a comet or an asteroid. But evidence has been mounting in recent years that the roughly six-mile-wide impactor belonged to a family of asteroids that formed beyond the orbit of Jupiter, and that rarely impact Earth.

Now, a team led by Mario Fischer-Gödde, a research scientist at the University of Cologne in Germany, has bolstered that case with the help of the rare element ruthenium. Ruthenium is abundant in asteroids but extremely scarce in Earth’s crust, making it a handy bellwether of past impacts by space rocks. The team searched for isotopes of ruthenium in the geological remnants of the Chicxulub impact.

The results revealed a uniform signature across the global layer of debris left by the impact, which is known as the Cretaceous-Paleogene (K-Pg) boundary. And that signature neatly matches the makeup of a group of space rocks known as carbonaceous asteroids because of their high-carbon content, according to a study published on Thursday in Science.

From the New York Times. 

Jurassic Mammals Lived Longer But Matured Later

In the Jurassic era early mammals lived much longer, but matured much later, impairing their ability to overcome threats to their respective species by reproducing early and often. Evolutionary fitness favored the modern pattern.

Researchers were able to image tiny growth rings in fossilized root cement -- the bone tissue that attaches the teeth to the jaw. "The rings are similar to those in trees, but on a microscopic level," explains Professor Thomas Martin of the Vertebrates -- Mammals working group at the University of Bonn Institute of Organismic Biology, who is a senior author of the study. "Counting the rings and analyzing their thickness and texture enabled us to reconstruct the growth patterns and lifespans of these extinct animals."

The researchers determined that the first signs of the growth patterns characteristic of modern mammals, such as a puberty growth spurt, started emerging roughly 150 million years ago. Early mammals grew much more slowly but lived substantially longer than today's small mammals, with lifespans of eight to fourteen years instead of just one or two as in modern mice, for example. However, it took early mammals years to reach sexual maturity, again in contrast to their modern descendants which reach sexual maturity in just a few months.

From Science Daily citing Elis Newham, et al., "The origins of mammal growth patterns during the Jurassic mammalian radiation." 10(32) Science Advances (2024) DOI: 10.1126/sciadv.ado4555

A Global Map Of The Last Glacial Maximum (And Dingos)

The Last Glacial Maximum land bridge in Southeast Asia (ca. 18,000-20,000 years ago) was not the source of dingos in Australia, although this land bridge may have facilitated the migration of modern humans who led to the extinction of relict archaic hominins to the west of the Wallace Line in what is now island Southeast Asia.

The Sahul Shelf and the Sunda Shelf during the past 12,000 years: Tasmania separated from the mainland 12,000 ybp, and New Guinea separated from the mainland 6,500–8,500 ybp.

It also turns out that recent discoveries have estimated that the arrival of the dingo (Australia's native dogs) in Australia may have been much more recently than previously estimated, since the oldest dingo remains in Australia were previously misdated. The current dates are consistent with an arrival of dingos in Australia via Austronesian mariners. Wikipedia explains that:

The earliest known dingo remains, found in Western Australia, date to 3,450 years ago. Based on a comparison of modern dingoes with these early remains, dingo morphology has not changed over thousands of years. This suggests that no artificial selection has been applied over this period and that the dingo represents an early form of dog. They have lived, bred, and undergone natural selection in the wild, isolated from other dogs until the arrival of European settlers, resulting in a unique breed.

In 2020, an MDNA study of ancient dog remains from the Yellow River and Yangtze River basins of southern China showed that most of the ancient dogs fell within haplogroup A1b, as do the Australian dingoes and the pre-colonial dogs of the Pacific, but in low frequency in China today. The specimen from the Tianluoshan archaeological site, Zhejiang province dates to 7,000 YBP (years before present) and is basal to the entire haplogroup A1b lineage. The dogs belonging to this haplogroup were once widely distributed in southern China, then dispersed through Southeast Asia into New Guinea and Oceania, but were replaced in China by dogs of other lineages 2,000 YBP.

The oldest reliable date for dog remains found in mainland Southeast Asia is from Vietnam at 4,000 YBP, and in Island Southeast Asia from Timor-Leste at 3,000 YBP. In New Guinea, the earliest dog remains date to 2,500–2,300 YBP from Caution Bay near Port Moresby, but no ancient New Guinea singing dog remains have been found. The earliest dingo remains in the Torres Straits date to 2,100 YBP. 

The earliest dingo skeletal remains in Australia are estimated at 3,450 YBP from the Mandura Caves on the Nullarbor Plain, south-eastern Western Australia; 3,320 YBP from Woombah Midden near Woombah, New South Wales; and 3,170 YBP from Fromme's Landing on the Murray River near Mannum, South Australia. 

Dingo bone fragments were found in a rock shelter located at Mount Burr, South Australia, in a layer that was originally dated 7,000-8,500 YBP. Excavations later indicated that the levels had been disturbed, and the dingo remains "probably moved to an earlier level." 

The dating of these early Australian dingo fossils led to the widely held belief that dingoes first arrived in Australia 4,000 YBP and then took 500 years to disperse around the continent. However, the timing of these skeletal remains was based on the dating of the sediments in which they were discovered, and not the specimens themselves.

In 2018, the oldest skeletal bones from the Madura Caves were directly carbon dated between 3,348 and 3,081 YBP, providing firm evidence of the earliest dingo and that dingoes arrived later than had previously been proposed. The next-most reliable timing is based on desiccated flesh dated 2,200 YBP from Thylacine Hole, 110 km west of Eucla on the Nullarbor Plain, southeastern Western Australia. When dingoes first arrived, they would have been taken up by indigenous Australians, who then provided a network for their swift transfer around the continent. Based on the recorded distribution time for dogs across Tasmania and cats across Australia once indigenous Australians had acquired them, the dispersal of dingoes from their point of landing until they occupied continental Australia is proposed to have taken only 70 years. The red fox is estimated to have dispersed across the continent in only 60–80 years.

At the end of the last glacial maximum and the associated rise in sea levels, Tasmania became separated from the Australian mainland 12,000 YBP, and New Guinea 6,500–8,500 YBP by the inundation of the Sahul Shelf. Fossil remains in Australia date to around 3,500 YBP and no dingo remains have been uncovered in Tasmania, so the dingo is estimated to have arrived in Australia at a time between 3,500 and 12,000 YBP. To reach Australia through Island Southeast Asia even at the lowest sea level of the last glacial maximum, a journey of at least 50 kilometres (31 mi) over open sea between ancient Sunda and Sahul was necessary, so they must have accompanied humans on boats.

Some best estimates of Austronesian migration are as follows:

Suggested early migration route of early Austronesians into and out of Taiwan based on ancient and modern mtDNA data. This hypothesis assumes the Sino-Austronesian grouping, a minority view among linguists. (Ko et al., 2014).

Map showing the migration of the Austronesians from Taiwan. Indonesia is reached ca. 3500 years BP, and Papua New Guinea is reached ca. 3300 years BP.

There is no direct evidence of the involvement of Austronesian mariners bringing dingos to Australia, but they were the only sea faring people in the region at the time who could have made the trip beyond the line of sight over deep waters in that era, were engaged in seafaring in the region at just about the right time, had ties to Southern China where dingos probably originated, and dingos pretty much had to have arrived in Australia with people by boat, as opposed to without human intervention. 

The timing and location of the earliest Australian dingo remains also suggests an introduction from someplace in Indonesia to someplace west of Cape York in Australia, rather than from Papua New Guinea to Cape York, which would have involved the shortest overwater journey. This was a trip well within the maritime capabilities of the Austronesians of 3500 BP to 3300 BP.

Ancient Giant Sharks Were Warm-Blooded

Being warm-blooded can support larger body size and ancient giant sharks called megalodons were among them. Most fish and reptiles are cold blooded.

Otodus megalodon (center in this illustration, preying on a seal) was warmer-blooded than the great white shark (top left). That warm-bloodedness may have helped it grow so large, but also ultimately spelled its doom as food sources dwindled.

Massive, megatoothed Otodus megalodon ran hot — the ancient shark was at least somewhat warm-blooded, new evidence shows.

Chemical measurements from fossil O. megalodon teeth suggest the sharks had higher body temperatures than their surrounding waters, researchers report June 26 in Proceedings of the National Academy of Sciences. Analyses of carbon and oxygen in the teeth of these and other sharks, both living and extinct, revealed that the giant shark’s body temperature was about 7 degrees Celsius warmer than estimated seawater temperatures at the time.

From Science News citing three papers:

* M. Griffiths et al., Endothermic physiology of extinct megatooth sharks. Proceedings of the National Academy of Sciences (June 26, 2023). doi: 10.1073/pnas.2218153120.

* J. A. Cooper et al. The extinct shark Otodus megalodon was a transoceanic superpredator: Inferences from 3D modeling. Science Advances (August 17, 2022). doi: 10.1126/sciadv.abm9424.

* H. Ferrón. Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks. PLOS ONE (September 22, 2017). doi: 10.1371/journal.pone.0185185.

Brain Size v. Body Size In Mammals

It turns out that the relationship between brain size and body size in mammals is pretty simple and universal if you don't insist on linear relationships.

Despite decades of comparative studies, fundamental questions remain about how brain and body size co-evolved. Divergent explanations exist concurrently in the literature for phenomena such as variation in brain relative to body size, variability in the scaling relationship across taxonomic levels and between taxonomic groups, and purported evolutionary trends. Here we resolve these issues using a comprehensive dataset of brain and body masses across the mammal radiation, and a method enabling us to study brain relative to body mass evolution while estimating their evolutionary rates along the branches of a phylogeny. 

Contrary to the rarely questioned assumption of a log-linear relationship, we find that a curvilinear model best describes the evolutionary relationship between log brain mass and log body mass. This model greatly simplifies our understanding of mammalian brain-body co-evolution: it can simultaneously explain both the much-discussed taxon-level effect and variation in slopes and intercepts previously attributed to complex scaling patterns. 

We also document substantial variation in rates of relative brain mass evolution, with bursts of change scattered through the tree. General trends for increasing relative brain size over time are found in only three mammalian orders, with the most extreme case being primates, setting the stage for the uniquely rapid directional increase that ultimately produced the computational powers of the human brain.

Chris Venditti, Joanna Baker, Robert A. Barton, "Co-evolutionary dynamics of mammalian brain and body size" bioRxiv (June 9, 2023) https://doi.org/10.1101/2023.06.08.544206

Story Of Human Evolution Not Actually Rewritten

Deep inside a South African cave, researchers say they have discovered graves dug by our ancient, small-brained relatives more than 100,000 years before the oldest known human burials, a claim that would revise the story of our evolution.

From the Washington Post.

Yes, this story about Homo naledi is cool.

Does it revise our story of evolution? 

No.

Does it spark debate among people who knew the existing story prior to this discovery? 

Not really, beyond the fine details of interpretation of the site.

This is a side story about a dead end hominin species that existed contemporaneously in Africa with the most direct ancestors of modern humans. It is basically a story from The Silmarillion of hominin evolution. It is entertaining, especially for hard core human evolution fans, but it doesn't really advance the plot.

Meanwhile, John Hawks discusses another recent paper he has co-authored on Homo Naledi from ten years after the original find about H. Naledi teeth.

More than 150 hominin teeth, dated to ∼330–241 thousand years ago, were recovered during the 2013–2015 excavations of the Dinaledi Chamber of the Rising Star cave system, South Africa. These fossils comprise the first large single-site sample of hominin teeth from the Middle Pleistocene of Africa. Though scattered remains attributable to Homo sapiens, or their possible lineal ancestors, are known from older and younger sites across the continent, the distinctive morphological feature set of the Dinaledi teeth supports the recognition of a novel hominin species, Homo naledi. This material provides evidence of African Homo lineage diversity that lasts until at least the Middle Pleistocene. Here, a catalog, anatomical descriptions, and details of preservation and taphonomic alteration are provided for the Dinaledi teeth. Where possible, provisional associations among teeth are also proposed. To facilitate future research, we also provide access to a catalog of surface files of the Rising Star jaws and teeth.

Delezene, L. K., Skinner, M. M., Bailey, S. E., Brophy, J. K., Elliott, M. C., Gurtov, A., Irish, J. D., Moggi-Cecchi, J., de Ruiter, D. J., Hawks, J., & Berger, L. R., "Descriptive catalog of Homo naledi dental remains from the 2013 to 2015 excavations of the Dinaledi Chamber, site U.W. 101, within the Rising Star cave system, South Africa." 180  Journal of Human Evolution 103372 (2023) 

https://doi.org/10.1016/j.jhevol.2023.103372

The Plague Was In Britain In 2000 BCE

We know that the plague was in Britain around 2000 BCE (the earliest known cases in Britain) based upon ancient plague DNA from that time period, according to the press release for the journal article: Pooja Swali, et al., "Yersinia pestis genomes reveal plague in Britain 4000 years ago." 14(1) Nature Communications (2023) DOI: 10.1038/s41467-023-38393-w

Biodiversity By Organism Size And Aggregate Biomass On Earth

Life on Earth is disproportionately made up of tiny organisms and large organisms, as measured by the aggregate biomass of organisms of each size.

A. Median carbon biomass (log scale) per log size as a function of body size with 95% confidence bounds (black dotted curves) cumulated across biological groups from 1000 bootstraps over within-group biomass and body size error distributions. Groups were organized from the least massive at the bottom to the most massive at the top for visibility on the log scale (ordered from top left to bottom right in color legend for group identity). Group biomasses are stacked so each group’s biomass is represented by its upper y-axis location minus its lower y-axis location (not by the upper y-axis location alone).

 

B. Median biomass in linear biomass scale. Confidence bounds are not shown here because they are so large as to obscure the median patterns on the linear scale.

Recent research has revealed the diversity and biomass of life across ecosystems, but how that biomass is distributed across body sizes of all living things remains unclear. We compile the present-day global body size-biomass spectra for the terrestrial, marine, and subterranean realms. To achieve this compilation, we pair existing and updated biomass estimates with previously uncatalogued body size ranges across all free-living biological groups. These data show that many biological groups share similar ranges of body sizes, and no single group dominates size ranges where cumulative biomass is highest. We then propagate biomass and size uncertainties and provide statistical descriptions of body size-biomass spectra across and within major habitat realms. 

Power laws show exponentially decreasing abundance (exponent -0.9±0.02 S.D., R^2 = 0.97) and nearly equal biomass (exponent 0.09±0.01, R^2 = 0.56) across log size bins, which resemble previous aquatic size spectra results but with greater organismal inclusivity and global coverage. In contrast, a bimodal Gaussian mixture model describes the biomass pattern better (R2 = 0.86) and suggests small (~10^−15 g) and large (~10^7 g) organisms outweigh other sizes by one order magnitude (15 and 65 Gt versus ~1 Gt per log size). The results suggest that the global body size-biomass relationships is bimodal, but substantial one-to-two orders-of-magnitude uncertainty mean that additional data will be needed to clarify whether global-scale universal constraints or local forces shape these patterns.

Eden W. Tekwa, Katrina A. Catalano, Anna L. Bazzicalupo, Mary I. O’Connor, Malin L. Pinsky. "The sizes of life." 18(3) PLOS ONE e0283020 (2023). DOI: 10.1371/journal.pone.0283020 via Science Daily. 

Comb Jellies Have Weird Nervous System

No other animal has a nervous system like a comb jelly, which suggests that they are in a very basal position in the animal kingdom's evolution.

Shimmering, gelatinous comb jellies wouldn’t appear to have much to hide. But their mostly see-through bodies cloak a nervous system unlike that of any other known animal, researchers report in the April 21 Science.

In the nervous systems of everything from anemones to aardvarks, electrical impulses pass between nerve cells, allowing for signals to move from one cell to the next. But the ctenophores’ cobweb of neurons, called a nerve net, is missing these distinct connection spots, or synapses. Instead, the nerve net is fused together, with long, stringy neurons sharing a cell membrane, a new 3-D map of its structure shows.

From Science News citing P. Burkhardt et al., "Syncytial nerve net in a ctenophore adds insights on the evolution of nervous systems" 380 Science 293 (April 21, 2023). doi: 10.1126/science.ade5645 

and 

A. Sebé-Pedrós et al., "Early metazoan cell type diversity and the evolution of multicellular gene regulation" Nature Ecology & Evolution (June 25, 2018) (published online) doi: 10.1038/s41559-018-0575-6