This Day In History: 1st Australopithecus africanus Announced

On this day in 1925 Raymond Dart announced the find of the “Taung child”, Australopithecus africanus, in The Star newspaper of Johannesburg, South Africa. Mr. Dart with his students made the find in the Taung limestone works in the Harts Valley of Bechuanaland. link

Australopithecus africanus

The Secret of The Dinosaur Skeleton!

Another Sunday funny book story from the Atomic Surgery!

Hot-Blooded Fish

Evidence for cranial endothermy in the opah (Lampris guttatus). 2009. R. M. Runcie, et al. J. Expt. Bio. 212: 461-470.

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For every palaeontologist who’s ever had the question, “were dinosaurs cold or hot-blooded?”, here’s another twist to throw in your answer:

Abstract: Cranial endothermy evolved independently in lamnid sharks, billfishes and tunas, and is thought to minimize the effects of ambient temperature change on both vision and neural function during deep dives. The opah, Lampris guttatus, is a large epipelagic–mesopelagic predator that makes repeated dives into cool waters to forage.

To determine if L. guttatus exhibits cranial endothermy, we measured cranial temperatures in live, decked fish and identified potential sources of heat and mechanisms to conserve heat. In 40 opah (95.1±7.6 cm fork length), the temperature of the tissue behind the eye was elevated by a mean (±s.e.m.) of 2.1±0.3°C and a maximum of 6.3°C above myotomal muscle temperature (Tm), used as a proxy for ambient temperature.

Cranial temperature varied significantly with Tm and temperature elevation was greater at lower Tm. The proximal region of the paired lateral rectus extraocular muscle appears to be the primary source of heat. This muscle is the largest extraocular muscle, is adjacent to the optic nerve and brain and is separated from the brain only by a thin layer of bone. The proximal lateral rectus muscle is darker red in color and has a higher citrate synthase activity, indicating a higher capacity for aerobic heat production, than all other extraocular muscles. Furthermore, this muscle has a layer of fat insulating it from the gill cavity and is perfused by a network of arteries and veins that forms a putative counter-current heat exchanger. Taken together, these results support the hypothesis that the opah can maintain elevated cranial temperatures.

Aurorachelys Migrated from Asia to NA Over a Tropical Arctic

The discovery of a tropical, freshwater, Asian turtle in the Canadian high arctic suggests that animals migrated from Asia to North America not around Alaska, as once thought, but directly across a freshwater sea floating atop the warm, salty Arctic Ocean.

From the press release:

The finding also suggests that a rapid influx of carbon dioxide some 90 million years ago was the likely cause of a super-greenhouse effect that created extraordinary polar heat.

"We've known there's been an interchange of animals between Asia and North America in the late Cretaceous period, but this is the first example we have of a fossil in the High Arctic region showing how this migration may have taken place," says John Tarduno. "We're talking about extremely warm, ice-free conditions in the Arctic region, allowing migrations across the pole."

Together with collaborator Donald Brinkman of the Royal Tyrrell Museum of Canada, they later named the fossil Aurorachelys, or aurora turtle. The turtle strongly resembles a freshwater Mongolian species, which raised obvious questions about how it came to be in the marine waters of the North American Arctic.

At the time the aurora turtle lived, the Arctic Ocean was probably even more separated from the global oceanic circulation system than it is today. Numerous rivers from the adjacent continents would have poured fresh water into the ancient Arctic sea. Since fresh water is lighter than marine water, Tarduno thinks it may have rested on top of the salty ocean water, allowing a freshwater animal such as the aurora turtle to migrate with relative ease.

"We found this turtle right on top of the last flood basalts—a large stretch of lava from a series of giant volcanic eruptions," says Tarduno. "That leads us to believe that the warming may have been caused by volcanoes pumping tremendous amounts of carbon dioxide into the Earth's atmosphere. There's evidence that this volcanic activity happened all around the planet—not just the Arctic. If it all happened on a short enough timescale, it could cause a super-greenhouse effect."

The paper will eventually turn up in Geology

Mark Schultz on NPR

Author and cartoonist, Mark Schultz (below), was interviewed on NPR’s All things Considered last Friday discussing his new book, Stuff of Life. The book is a primer on genetics presented in the form of a graphic novel.

You can listen to the interview HERE.


Can I make that out to "eBay buyer"?


Art by Mark Schultz

This a good time to remind you that Mark Schultz’s exclusive signed print of Centrosaurus brinkmani is still availbale only from the palaeoblog. If you’re interested in getting one, send me an e-mail at “palaeoblog @ yahoo dot ca”. There’s a deal for blog readers if you order more than one.

Evidence of Combat in Triceratops

Evidence of Combat in Triceratops. 2009. A. A. Farke, et al. PLoS ONE 4(1): e4252. An open access article. Click the link to download the PDF.

Image by Lukas Panzarin/Raymond M. Alf Museum of Paleontology

Abstract [edited]: The horns and frill of Triceratops and other horned dinosaurs) are interpreted variously as display structures or as weapons against conspecifics and predators. Lesions (in the form of periosteal reactive bone, healing fractures, and alleged punctures) on Triceratops skulls have been used as anecdotal support of intraspecific combat similar to that in modern horned and antlered animals. If ceratopsids with different cranial morphologies used their horns in such combat, this should be reflected in the rates of lesion occurrence across the skull.

We used a G-test of independence to compare incidence rates of lesions in Triceratops (which possesses two large brow horns and a smaller nasal horn) and the related ceratopsid Centrosaurus (with a large nasal horn and small brow horns), for the nasal, jugal, squamosal, and parietal bones of the skull. The two taxa differ significantly in the occurrence of lesions on the squamosal bone of the frill (P = 0.002), but not in other cranial bones (P>0.20).

This pattern is consistent with Triceratops using its horns in combat and the frill being adapted as a protective structure for this taxon. Lower pathology rates in Centrosaurus may indicate visual rather than physical use of cranial ornamentation in this genus, or a form of combat focused on the body rather than the head.

Read the story at Discovery Channel.com

Our Knowledge of Dino Evolution Is Pretty Good

The Modified Gap Excess Ratio (GER*) and the Stratigraphic Congruence of Dinosaur Phylogenies. 2009. M. Wills, et al. Sys. Bio. 57: 891 - 904

Superman © DC Comics

Scientists’ claim our knowledge of the evolution of dinosaurs is remarkably complete.

The researchers found that the fossil record for the dinosaurs studied, ranging from gigantic sauropods to two-legged meat eaters such as T. rex, matched very well with the evolutionary tree, meaning that the current view of evolution of these creatures is very accurate.

The researchers studied gaps in the fossil record, so-called ‘ghost ranges’, where the evolutionary tree indicates there should be fossils but where none have yet been found. They mapped these gaps onto the evolutionary tree and calculated statistical probabilities to find the closeness of the match.

“Pinning down an accurate date for some fossils can also prove difficult. For example, the oldest fossil may be so incomplete that it becomes uncertain as to which group it belongs. This is particularly true with fragments of bones. Our study made allowances for this uncertainty.

“We are excited that our data show an almost perfect agreement between the evolutionary tree and the ages of fossils in the rocks. This is because it confirms that the fossil record offers an extremely accurate account of how these amazing animals evolved over time and gives clues as to how mammals and birds evolved from them.”

The Other Evolution

Hotspots of Biased Nucleotide Substitutions in Human Genes. 2009. J. Berglund, et al. PLOS 7(1): e1000026.

Why have some of our genes evolved rapidly? It is widely believed that Darwinian natural selection is responsible, but new research suggests that a separate neutral (nonadaptive) process has made a significant contribution to human evolution.

From the press release:

The researchers identified fast evolving human genes by comparing our genome with those of other primates. Surprisingly, the patterns of molecular evolution in many of the genes they found did not contain signals of natural selection. Instead, their evidence suggests that a separate process known as biased gene conversion (BGC) has speeded up the rate of evolution in certain genes. This process increases the rate at which certain mutations spread through a population, regardless of whether they are beneficial or harmful.

© DC Comics

"The research not only increases our understanding of human evolution, but also suggests that many techniques used by evolutionary biologists to detect selection may be flawed" says Matthew Webster

BGC is thought to be strongest in regions of high recombination, and can cause harmful mutations can spread through populations. The results lead to the provocative hypothesis that, rather than being the result of Darwinian selection for new adaptations, many of the genetic changes leading to human-specific characters may be the result of the fixation of harmful mutations. This contrasts the traditional Darwinistic view that they are the result of natural selection in favour of adaptive mutations.

The Origin of Woody Tissue

Discovery of Lignin in Seaweed Reveals Convergent Evolution of Cell-Wall Architecture. 2009. P. T. Martone, et al. Current Biology 19: 169-175.

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Land plants' ability to sprout upward through the air, unsupported except by their own woody tissues, has long been considered one of the characteristics separating them from aquatic plants, which rely on water to support them. Now lignin, one of the chemical underpinnings vital to the self-supporting nature of land plants – and thought unique to them – has been found in marine algae.

From the press release:

"All land plants evolved from aquatic green algae and scientists have long believed that lignin evolved after plants took to land as a mechanical adaptation for stabilizing upright growth and transporting water from the root," says Martone.

"Because red and green algae likely diverged more than a billion years ago, the discovery of lignin in red algae suggests that the basic machinery for producing lignin may have existed long before algae moved to land."

Alternatively, algae and land plants may have evolved the identical compound independently, after they diverged.

"The pathways, enzymes and genes that go into making this stuff are pretty complicated, so to come up with all those separately would be really, really amazing," says Denny. "Anything is possible, but that would be one hell of a coincidence."

The team's finding provides a new perspective on the early evolution of lignified support tissues – such as wood – on land, since the seaweed tissues that are most stressed by waves crashing on shore appear to contain the most lignin, possibly contributing to mechanical support, says Martone.

Born This Day: Eugène Dubois

Jan. 28, 1858-Dec. 16, 1940

Eugene Dubois joined the Dutch Army as a medical officer, and used spare time from his medical duties to search for fossils, first in Sumatra and then in Java. He searched on the banks of the Solo River, with two assigned engineers and a crew of convict labourers to help him. In September 1890, his workers found a human, or human-like, fossil at Koedoeng Broeboes. This consisted of the right side of the chin of a lower jaw and three attached teeth. In August 1891 he found a primate molar tooth.

Two months later and one meter away was found an intact skullcap, the fossil which would be known as Java Man. In August 1892, a third primate fossil, an almost complete left thigh bone, was found between 10 and 15 meters away from the skullcap.

In 1894 Dubois published a description of his fossils, naming them Pithecanthropus erectus (now Home erectus), describing it as neither ape nor human, but something intermediate. In 1895 he returned to Europe to promote the fossil and his interpretation. A few scientists enthusiastically endorsed Dubois' work, but most disagreed with his interpretation. Many scientists pointed out similarities between the Java Man skullcap and Neandertal fossils.

Around 1900 Dubois ceased to discuss Java Man, and hid the fossils in his home while he moved on to other research topics. geology and paleontology. It was not until 1923 that Dubois, under pressure from scientists, once again allowed access to the Java Man fossils. That and the discovery of similar fossils caused it to once again become a topic of debate.

Skull cap (Trinil 2, holotype of Home erectus) from HERE.

Died This Day: Adam Sedgwick

March 22, 1785 - January 27, 1873

From Today In Science History:

Sedgwich was an English geologist who first applied the name Cambrian to the geologic period of time, now dated at 570 to 505 million years ago. In 1818 he became Woodwardian Professor of Geology at Cambridge, holding a chair that had been endowed ninety years before by the natural historian John Woodward.

He lacked formal training in geology, but he quickly became an active researcher in geology and paleontology. Many years after Sedgwick's death, the geological museum at Cambridge was renamed the Sedgwick Museum of Geology in his honor. The museum is now part of the Department of Earth Sciences at Cambridge University

No Comet Impact 13,000 Years Ago

Wildfire responses to abrupt climate change in North America. 2009. J.R. Marlon, et al. PNAS, early edition.

Devil Dinosaur © Marvel Comics

New data disproves the recent theory that a large comet exploded over North America 12,900 years ago, causing a shock wave that travelled across North America at hundreds of km/hr, triggering continent-wide wildfires.

From the press release:

Scientists tested the theory by examining charcoal and pollen records to assess how fire regimes in North America changed between 15 and 10,000 years ago, a time of large and rapid climate changes.

Their results provide no evidence for continental-scale fires, but support the fact that the increase in large-scale wildfires in all regions of the world during the past decade is related to an increase in global warming.

The end of the Younger Dryas, about 11,700 years ago, was an interval when the temperature of Greenland warmed by over 5°C in less than a few decades. The team used 35 records of charcoal accumulation in lake sediments from sites across North America to see whether fire regimes across the continent showed any response to such rapid warming.

They found clear changes in biomass burning and fire frequency whenever climate changed abruptly, and most particularly when temperatures increased at the end of the Younger Dryas cold phase.

Born This Day: Roy Chapman Andrews

Jan. 26, 1884 – March 11, 1960.

Photo from Parade of Life Through The Ages, by Charles Knight, Nat. Geo., Feb. 1942.

From the American Museum of Natural History web site:

Adventurer, administrator, and Museum promoter — Andrews spent his entire career at the American Museum of Natural History, where he rose through the ranks from departmental assistant, to expedition organizer, to Museum director. He became world famous as leader of the Central Asiatic Expeditions, a series of expeditions to Mongolia that collected, among other things, dinosaur eggs. But on these expeditions, Andrews himself found few fossils, and during his career he was not known as an influential scientist. Instead, Andrews filled the role of promoter, creating immense excitement and successfully advancing the research and exhibition goals of the museum.

Learn about the Roy Chapman Andrews Society HERE.

What Killed The Dinosaurs? Now It Can Be Told!

The good doctors over at the Atomic Surgery have uncovered the truth about the extinction of the dinosaurs (except birds of course!), and why the Earth supports life.

Read about their amazing discovery HERE!

Born This Day: Theodosius Dobzhansky

Jan.25, 1900–Dec. 18, 1975

Dobzhansky is noted for being one of the architects of the modern Synthetic Theory of evolution. During the first 20 years of the 20th century, Darwin's theory of natural selection had fallen out of favor among scientists. Many thought it insufficient to explain the origin of adaptations, while new discoveries of gene mutations seemed to them to be incompatible with Darwinian models of change.

But in 1937 Dobzhansky published his book, Genetics and the Origin of Species, that was the first systematic overview view encompassing organic diversity, variation in natural populations, selection, isolating mechanisms (a term he coined) and species as natural units.

Later, working with Sewall Wright, he went on to demonstrate how evolution can produce stability and equilibrium in populations rather than constant directional change. link. image.

Debuted This Day (1956): The Animal World

“2 Billion Years in the Making!”

Produced and directed by Irwin Allen, whose long career included such TV hits as Lost In Space and Voyage To The Bottom Of The Sea, and movies like The Poseidon Adventure and The Towering Inferno.

The Animal World was one of the first films to present dinosaurs in the quasi-nature documentary so beloved by the Discovery Channel today. Rarely seen now, it featured about 10 minutes of great dinosaur stop-animation by Ray Harryhausen with Willis O’Brien. The entire sequence was released as an extra on the 2003 DVD release of The Black Scorpion.

"Hobbits" Were A Separate Species

Size, shape, and asymmetry in fossil hominins: The status of the LB1 cranium based on 3D morphometric analyses. 2008. K.L. Baab and K.P. McNulty. J. of Human Evolution, online Dec. 4, 2008.

Anthro © DC Comics
Scientists continue to debate whether the Flores "hobbits" were a separate species

Abstract [edit]: The unique set of morphological characteristics of the Liang Bua hominins (Homo floresiensis) has been attributed to explanations as diverse as insular dwarfism and pathological microcephaly. This study examined the relationship between cranial size and shape across a range of hominin and African ape species to test whether or not cranial morphology of LB1 is consistent with the basic pattern of static allometry present in these various taxa.

Correlations between size and 3D cranial shape were explored using principal components analysis in shape space and in Procrustes form space. Additionally, patterns of static allometry within both modern humans and Plio-Pleistocene hominins were used to simulate the expected cranial shapes of each group at the size of LB1. These hypothetical specimens were compared to LB1 both visually and statistically.

A model of Homo floresiensis's skull (right) is shown with a modern human's (left) and a fragment of a recently found skull from Palau (center). Photo: Stephen Alvarez

Results of most analyses indicated that LB1 best fits predictions for a small specimen of fossil Homo but not for a small modern human. This was especially true for analyses of neurocranial landmarks. Results from the whole cranium were less clear about the specific affinities of LB1, but, importantly, demonstrated that aspects of facial morphology associated with smaller size converge on modern human morphology. This suggests that facial similarities between LB1 and anatomically modern humans may not be indicative of a close relationship.

Taken together, these findings suggest that H. floresiensis was most likely the diminutive descendant of a species of archaic Homo, although the details of this evolutionary history remain obscure.

Read more at National Geographic News.

Mexico Seizes Largest Batch of Fossils

From the Latin American Herald Tribune:

Mexican authorities revealed that they recovered 389 fossils, among which are the remains of dinosaurs and trilobites hundreds of millions of years old, that were illegally being offered for sale at an antiquities store in the northern state of Nuevo Leon.

The director of the Monterrey office of the National Anthropology and History Institute (INAH), Hector Jaime Treviño, said that this is the most important confiscation to date in Mexico that includes unique fossils.

They emphasized that no museum in Mexico has more than 200 pieces of this kind and this collection contains almost double that number, a group that should be sufficient to mount two simultaneous exhibits.

Both officials said that the pieces were recovered in a operation in 2006 by the Attorney General's Office from a shop in the Monterrey suburb of San Pedro Garza Garcia.

Among the pieces confiscated are remains of mammoths, camels, early horses, sharks, mastodons, various dinosaurs, ammonites (giant marine mollusks that lived about 100 million years ago) and trilobites.

INAH announced that it will send an exhibition of the trove of fossils around the country so that the public can view the items.

The New York Times on Nat Murphy

image: JRDI

Things don't look so good for Nat Murphy. Read The New York Times article HERE

Fossil Sphenodon Ignites Debate Over Kiwi Submergence

A sphenodontine (Rhynchocephalia) from the Miocene of New Zealand and palaeobiogeography of the tuatara (Sphenodon). 2009. M. Jones et al. Proc. Royal Soc. B.

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The fossil of a lizard-like New Zealand reptile dating back 18 million years has triggered fresh arguments over whether the continent was fully submerged some 25 million years ago.

From the press release:

Today, the endangered New Zealand tuatara (Sphenodon) is a lizard-like reptile that is the only survivor of a group that was globally widespread at the time of the dinosaurs. The tuatara lives on 35 islands scattered around the coast of New Zealand, mainland populations having become extinct with the arrival of humans and associated animals some 750 years ago.

The oldest known Sphenodon fossil dates to the Pleistocene era (around 34,000 years old), while the new discovery dates to the Early Miocene some 19 to 16 million years ago (Mya).The fossil, of jaws and dentition closely resembling those of the present-day tuatara, bridges a gap of nearly 70 million years in the fossil record of the group between the Late Pleistocene of New Zealand and the Late Cretaceous of Argentina.

"It seems more likely that some local land surface persisted during the drowning of the continent and allowed the ancestors of the tuatara along with some frogs, birds and mammals (known from the Miocene but now extinct) to survive the transgression, although the extent of the remaining land surface at the time is open to speculation. However, even if Zealandia was reduced to only one per cent of today's surface area it would still represent over 2,500 km², well over 1,000 times the surface area of Stephen's Island (1.5 km²), where over 30,000 tuatara currently live."