Saturday, January 31, 2009

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.

Friday, January 30, 2009

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

Thursday, January 29, 2009

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.”

Wednesday, January 28, 2009

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.

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.

Tuesday, January 27, 2009

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

Monday, January 26, 2009

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 promoterAndrews 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.

Sunday, January 25, 2009

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.

Saturday, January 24, 2009

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.

Friday, January 23, 2009

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.

Thursday, January 22, 2009

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.

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."

Wednesday, January 21, 2009

Charles H. Schneer, R.I.P.

Producer Charles H. Schneer, who worked with Ray Harryhausen on films including "Jason and the Argonauts," died Jan. 21 in Boca Raton, Fla. He was 88. Schneer produced their biggest hit of the 1950s, "The Seventh Voyage of Sinbad." They continued with Columbia sci-fi titles including "The Three Worlds of Gulliver," "Mysterious Island" and the influential "Jason and the Argonauts."

He later worked with with Harryhausen on "The Valley of Gwangi," "The Golden Voyage of Sinbad," "Sinbad and the Eye of the Tiger" and their final film, the bigger-budget "Clash of the Titans". Story from Variety.

Thanks to Tim!

Minotaurasaurus, a new ankylosaur from the Gobi

Skull of Minotaurasaurus ramachandrani, a new Cretaceous ankylosaur from the Gobi Desert. 2009. Current Science 96: 65-70. Download the PDF.

So, where exactly did it come from and was it legally collected? If someone can fill me in I'd appreciate it.

Stupid Fossil Hunting!

Tuesday, January 20, 2009

New Feather Type Found On Beipiaosaurus

A new feather type in a nonavian theropod and the early evolution of feathers. 2009. Xing Xu, et al. PNAS 106: 832-834.

Paleontologists have proposed that “dinofuzz” evolved before feathers. Now researchers have finally found an important yet long-missing piece of the feather lineage: single, unbranched filaments.
From Science News:

The unbranched structures appear on a newly discovered specimen of Beipiaosaurus, a feathered dinosaur that lived in what is now China about 120 million years ago. The filaments, which measure between 10 and 15 centimeters long, are broad — about 2 mm wide for most of their length. They’re found only on the creature’s head, neck and tail. The filaments probably served as display structures, just as many similarly placed feathers do on modern birds.

Abstract: All described feathers in nonavian theropods are composite structures formed by multiple filaments. They closely resemble relatively advanced stages predicted by developmental models of the origin of feathers, but not the earliest stage. Here, we report a feather type in two specimens of the basal therizinosaur Beipiaosaurus, in which each individual feather is represented by a single broad filament.

This morphotype is congruent with the stage I morphology predicted by developmental models, and all major predicted morphotypes have now been documented in the fossil record. This congruence between the full range of paleontological and developmental data strongly supports the hypothesis that feathers evolved and initially diversified in nonavian theropods before the origin of birds and the evolution of flight.

Thanks to Sukie.

Monday, January 19, 2009

Died This Day: Capt. Englehorn

Dec. 2, 1875 - Jan. 19, 1965

Frank Reicher was a German actor, director and producer born in Munich, Germany. During the early part of the twentieth century he was often on Broadway, occasionally in leading roles, but he is most familiar to modern audiences as a supporting character actor in films. He is probably best known for playing Captain Englehorn in the movies King Kong and Son of Kong in 1933. link

Sunday, January 18, 2009

I Battled The Evolution Beasts!

Well, not me personally, but someone did over at Atomic Surgery.

The Inner Ear of Archaeopteryx

Inner ear anatomy is a proxy for deducing auditory capability and behaviour in reptiles and birds. 2009. S. A. Walsh et al. Proc. Royal Soc. B: on-line January 13, 2009.

image from the Witmer lab
The earliest known bird, the magpie-sized Archaeopteryx lithographica, was able to hear like a modern emu.
From the BBC:

A team of scientists found the length of a part of the inner ear of birds and reptiles could be used to predict their hearing ability. The researchers tested whether the length of the cochlear duct (part of the cochlea - the organ of hearing in animals, which lies in the inner ear) could be used to infer hearing ability in a group of modern birds and reptiles.

Archaeopteryx had an average hearing range of approximately 2,000 Hz. "This means it had similar hearing to modern emus, which have some of the most limited hearing ranges of modern birds."

They found that animals with a long cochlear duct tended to have the best hearing and vocal ability. Modern bird species are known to possess relatively longer cochlear ducts than living reptiles.

A long cochlear duct is also an indicator of an individual's complex vocal communication, living in groups and even habitat choice. This appears to be true for both mammals and birds.

Abstract: Inferences of hearing capabilities and audition-related behaviours in extinct reptiles and birds have previously been based on comparing cochlear duct dimensions with those of living species. However, the relationship between inner-ear bony anatomy and hearing ability or vocalization has never been tested rigorously in extant or fossil taxa. Here, micro-computed tomographic analysis is used to investigate whether simple endosseous cochlear duct (ECD) measurements can be fitted to models of hearing sensitivity, vocalization, sociality and environmental preference in 59 extant reptile and bird species, selected based on their vocalization ability. Length, rostrocaudal/mediolateral width and volume measurements were taken from ECD virtual endocasts and scaled to basicranial length. Multiple regression of these data with measures of hearing sensitivity, vocal complexity, sociality and environmental preference recovered positive correlations between ECD length and hearing range/mean frequency, vocal complexity, the behavioural traits of pair bonding and living in large aggregations, and a negative correlation between ECD length/rostrocaudal width and aquatic environments. No other dimensions correlated with these variables. Our results suggest that ECD length can be used to predict mean hearing frequency and range in fossil taxa, and that this measure may also predict vocal complexity and large group sociality given comprehensive datasets.

Get everything you need to know from co-author Larry Witmer’s lab

Saturday, January 17, 2009

Anchiornis huxleyi: New Maniraptorian From China

A new feathered maniraptorian dinosaur fossil that fills a morphological gap in avain origin. Xu X., et al. Chinese Science Bulletin 54, 1861-9541 (Online).

Abstract: Recent fossil discoveries have substantially reduced the morphological gap between non-avian and avian dinosaurs, yet avians including Archaeopteryx differ from non-avian theropods in their limb proportions. In particular, avians have proportionally longer and more robust forelimbs that are capable of supporting a large aerodynamic surface.

Here we report on a new maniraptoran dinosaur, Anchiornis huxleyi gen. et sp. nov., based on a specimen collected from lacustrine deposits of uncertain age in western Liaoning, China. With an estimated mass of 110 grams, Anchiornis is the smallest known non-avian theropod dinosaur.

It exhibits some wrist features indicative of high mobility, presaging the wing-folding mechanisms seen in more derived birds and suggesting rapid evolution of the carpus. Otherwise, Anchiornis is intermediate in general morphology between non-avian and avian dinosaurs, particularly with regard to relative forelimb length and thickness, and represents a transitional step toward the avian condition.

In contrast with some recent comprehensive phylogenetic analyses, our phylogenetic analysis incorporates subtle morphological variations and recovers a conventional result supporting the monophyly of Avialae.

Read about it at National Geographic News.

Thanks To Matt Lamanna!

Oops! I completely forgot to let the local blog readers know that Dr. Matthew C. Lamanna, Assistant Curator of Vertebrate Paleontology at the Carnegie Museum of Natural History, was speaking here at the CMNH last night. D’oh! That’s what I get for trying to juggle too much.

Matt gave another expectional talk to a near capacity crowd, featuring his research on Gansus yumenensis, a 115 million-year-old amphibious bird from China and explained its implications for the rise of modern birds.

Many thanks to Matt and his wonderful fiancé, Mandi, for taking the time to drive up to Cleveland through the exceptionally cold weather.

Born This Day: August Weismann

Jan. 17, 1834 – Nov. 5, 1914

From Today In Science History:

August (Friedrich Leopold) Weismann was a German biologist and one of the founders of the science of genetics. He is best known for his opposition to the doctrine of the inheritance of acquired traits and for his "germ plasm" theory, the forerunner of DNA theory. Weismann conceived the idea, arising out of his early observations on the Hydrozoa, that the germ cells of animals contain "something essential for the species, something which must be carefully preserved and passed on from one generation to another."

Weismann envisioned the hereditary substances from the two parents become mixed together in the fertilized egg and a form of nuclear division in which each daughter nucleus receives only half the original ancestral germ plasms.

More info from Science World. image

Friday, January 16, 2009

Born This Day: Caroline Munro

Art © Mark Schultz
Munro is probably best known for her role in in the Bond film The Spy Who Loved Me (1977). She had a long career in a variety of genre films including a stint with Hammer Films, and notably with Ray Harryhausen as the slave girl, Margiana, in The Golden Voyage of Sinbad (1974).

She takes a bow on the Palaeoblog both for being the Godmother of Harryhausen’s daughter and for her role as Princess Dia in At the Earth’s Core (1976)

Born This Day: Ruth Rose

Jan. 16, 1896 - June 8, 1978

Ruth Rose was the daughter of Edward E. Rose. In 1926 she meet (and later married) cinematographer Ernest Schoedsack when they were both working on a New York Geological Society expedition to the Galapagos Islands. Together with partner and fellow producer director, Meriam C. Cooper, and animator Willis O’Brien, they made “King Kong”, released in 1933. Rose shared in many of Schoedsack’s and Cooper’s wildness film productions, and worked as a writer or script doctor on King Kong, Son of Kong, She, The Last Days of Pompeii and Mighty Joe Young.

The photo from King Kong (above) is of Bruce Cabot, Fay Wray and Robert Armstrong, but Rose clearly modeled the characters they played after Schoedsack, herself, and Cooper.

Thursday, January 15, 2009

The Braincase & Jaws of a Devonian 'Acanthodian'

The braincase and jaws of a Devonian 'acanthodian' and modern gnathostome origins. 2009. M. D. Brazeau. Nature 457: 305-308

Abstract: Modern gnathostomes (jawed vertebrates) emerged in the early Palaeozoic era, but this event remains unclear owing to a scant early fossil record. The exclusively Palaeozoic 'acanthodians' are possibly the earliest gnathostome group and exhibit a mosaic of shark- and bony fish-like characters that has long given them prominence in discussions of early gnathostome evolution. Their relationships with modern gnathostomes have remained mysterious, partly because their un-mineralized endoskeletons rarely fossilized.

Here I present the first-known braincase of an Early Devonian (approximately 418–412 Ma) acanthodian, Ptomacanthus anglicus, and re-evaluate the interrelationships of basal gnathostomes. Acanthodian braincases have previously been represented by a single genus, Acanthodes, which occurs more than 100 million years later in the fossil record.

The braincase of Ptomacanthus differs radically from the osteichthyan-like braincase of Acanthodes in exhibiting several plesiomorphic features shared with placoderms and some early chondrichthyans. Most striking is its extremely short sphenoid region and its jaw suspension, which displays features intermediate between some Palaeozoic chondrichthyans and osteichthyans.

Click to enlarge
Phylogenetic analysis resolves Ptomacanthus as either the most basal chondrichthyan or as the sister group of all living gnathostomes. These new data alter earlier conceptions of basal gnathostome phylogeny and thus help to provide a more detailed picture of the acquisition of early gnathostome characters.

Read the press release from Uppsala U.

I’m sure that Martin will have more about this up on his “Lancet” blog.
And belated congrats to Martin for defending his Ph.D. on "Endocranial Morphology and Phylogeny of Palaeozoic Gnathostomes" last Novemeber!

Died This Day: Alpheus Hyatt

April 5, 1838 - January 15, 1902

From Today in Science History:

U.S. zoologist and paleontologist who studied invertebrate fossil records, the evolution of the cephalopods (a class of mollusks including squids and octopuses) and the development of primitive organisms.

Along with E. Cope, Hyatt was the most prominent American neo-Lamarckian. Based on the analogy of ontogeny with phylogeny, Hyatt claimed that lineages, like individuals, had cycles of youth, old age, and death (extinction). This idea became the bulwark of orthogenetic theories in the U.S. Hyatt was the founder and first editor of the American Naturalist, and first president of Woods Hole laboratory.

Died This Day: Jean-Baptiste-Julien d' Omalius d'Halloy

Feb. 16, 1783 - Jan. 15, 1875

d'Halloy was a Belgian geologist who was an early proponent of evolution and was acknowledged by Charles Darwin in his preface to ‘On The Origin of the Species’ for his opinions on the origin of new species through descent with modification.

He determined the stratigraphy of the Carboniferous and other rocks in Belgium and the Rhine provinces, and also made detailed studies of the Tertiary deposits of the Paris Basin. link

Opened To The Public (1759): The British Museum

On this day in 1759, the British Museum, in Bloomsbury, London, the world's oldest public national museum, opened to the public who were admitted in small groups, by ticket obtained in advance, for a conducted tour.

It was established on June 7, 1753 when King George II gave his royal assent to an Act of Parliament to acquire the collection of Sir Hans Sloane. In his will, he had offered the nation his lifetime collection of 71,000 objects, mostly plant and animal specimens. In return, he requested £20,000 for his heirs (which today would be over £2,000,000). The present museum buildings date from the mid-19th century. Its natural history collection moved to its own museum in 1881. link

Wednesday, January 14, 2009

Darwin: A Graphic Biography

Apparently next week will see the publication of, Darwin: A Graphic Biography, the latest 100-page comic book from Eugene Byrne and Simon Gurr. link

From Darwin 200:
“A comic history of Darwin and the Beagle voyage has been commissioned by the Bristol Cultural Development Partnership.

Simon Gurr and Eugene Byrne are writing and illustrating a biography of Charles Darwin in comic form. The book will convey the essence of Darwin's life and legacy in an accessible style.

The comic book will cover Darwin's voyage on the Beagle, his subsequent studies, the publication of On the Origin of Species and the public reaction to it at the time. The book will also refer to contemporary controversies such as genetic engineering and intelligent design.

The illustrator and writer have worked on several other publications, including a graphic biography of Isambard Kingdom Brunel and a history of Bristol in comic form.

200,000 copies of Darwin: a graphic biography will be published in 2009, to mark Darwin's 200th birthday. It will be distributed free of charge.”
Hey, here’s a thought; since the 2009 annual meeting of the Society of Vertebrate Paleontology is being held in Bristol this year, perhaps the Host Committee could arrange for the registrants to get a copy in their registration packages. Someone should mention this to Mike Benton.

More Evidence For Snowball Earth

Stretching the Envelope of Past Surface Environments: Neoproterozoic Glacial Lakes from Svalbard. 2008. H. Bao et al. Science 323: 119 – 122

From National Geographic News:

Oxygen trapped in 635-million-year-old rocks from the Arctic has revealed that ancient Earth once had an otherworldly atmosphere that might have helped melt millions of years' worth of deep freeze. Analysis of the chemical composition of rocks from the Norwegian island chain of Svalbard shows a surprisingly low amount of a particular type, or isotope, of oxygen.

Reduced levels of this isotope are linked to high levels of carbon dioxide in the atmosphere, and the new data suggest ancient Earth might have had 300 to 1,000 times more CO2 than current levels.

Bao and colleagues think their finding supports the "snowball Earth" theory, which says that snow and ice accumulation worldwide once reached a threshold that caused the entire planet to stay frozen for millions of years.

Abstract: The oxygen isotope composition of terrestrial sulfate is affected measurably by many Earth-surface processes. During the Neoproterozoic, severe "snowball" glaciations would have had an extreme impact on the biosphere and the atmosphere. Here, we report that sulfate extracted from carbonate lenses within a Neoproterozoic glacial diamictite suite from Svalbard, with an age of 635 million years ago, falls well outside the currently known natural range of triple oxygen isotope compositions and indicates that the atmosphere had either an exceptionally high atmospheric carbon dioxide concentration or an utterly unfamiliar oxygen cycle during deposition of the diamictites. image

Texas State Dino Facing Name Change

The official State Dinosaur of Texas is up for a new name, based on research that proved the titleholder has been misidentified.
From the press release:

State Rep. Charles Geren of Fort Worth filed a resolution Jan. 7 to change the name of the state dinosaur from Pleurocoelus to Paluxysaurus jonesi to correctly name the massive sauropod whose tracks and bones litter the central Texas Jones Ranch. Peter Rose is the scientist behind the name change: His master's level study of dinosaur bones at SMU eventually led him to dispute the long-accepted notion that the large, sauropod bones found in and around the Paluxy River near Glen Rose, Texas, were the same as Pleurocoelus bones first found in Maryland in the late 1800s.

Rose determined it was a different dinosaur altogether – a previously unrecognized genus and species he named Paluxysaurus jonesi, after W.W. Jones, the owner of the land on which the fossils were found. Once Rose's discovery was published in 2007, Pleurocelus' grand Texas title no longer fit.

SMU geological sciences professor Louis Jacobs, who was Rose's mentor, said that nobody before Rose had made an adequate study of the sauropod bones found at the Glen Rose site. Jacobs has described Texas as a kind of "free trade zone for the age of reptiles" since dinosaurs from three different geologic time periods have been found in three different geographic areas of the state. Paluxysaurus jonesi is believed to have lived 112 million years ago during the Cretaceous Period. image

Monday, January 12, 2009

Reverse Evolution In Real Time

Experimental evolution reveals natural selection on standing genetic variation. 2009. H. Teotónio et al. Nature Genetics. Published online: 11 January 2009

My Greatest Adventure (1957) © DC Comics
Scientists provide the first quantitative genetic evidence of why replaying Stephen Jay Gould’s “tape of life” would produce different results each time.
From the press release:

Scientists have recreated natural selection in real-time in the laboratory and provide the first quantitative evidence for natural selection on so-called standing genetic variation – a process long thought to be operating in natural populations that reproduce sexually but which, until now, had never been demonstrated.

They used the fruit fly, Drosophila melanogaster, derived from an original group of flies, harvested from the wild back in 1975. These ancestral flies were grown in the laboratory, for two decades, under different environmental conditions, (such as starvation and longer life-cycles) so that each population was selected for specific characteristics. Then scientists placed these populations back in the ancestral environment for 50 generations to impose reverse evolution on the flies, and then looked at the genetic changes in certain areas of chromosome 3 of these flies.

Says Henrique, 'In 2001 we showed that evolution is reversible in as far as phenotypes are concerned, but even then, only to a point. Indeed, not all the characteristics evolved back to the ancestral state. Furthermore, some characteristics reverse-evolved rapidly, while others took longer.

Reverse evolution seems to stop when the populations of flies achieve adaptation to the ancestral environment, which may not coincide with the ancestral state. In this study, we have shown that underlying these phenomena is the fact that, at the genetic level, convergence to the ancestral state is on the order of 50%, that is, on average, only half of the gene frequencies revert to the ancestral gene frequencies – evolution is contingent upon history at the genetic level too'.

Saturday, January 10, 2009

Died This Day: Carolus Linneaus

Born May 23, 1707 – Jan. 10, 1778.

From the Linnean Society:

Linnaeus was born in 1707 in Sweden. He headed an expedition to Lapland in 1732, travelling 4,600 miles and crossing the Scandinavian Peninsula by foot to the Arctic Ocean. On the journey he discovered a hundred botanical species. He undertook his medical degree in 1735 in the Netherlands. In 1735, he published Systema Naturae, his classification of plants based on their sexual parts.

His method of binomial nomenclature using genus and species names was further expounded when he published Fundamenta Botanica (1736) and Classes Plantarum (1738). This system used the flower and the number and arrangements of its sexual organs of stamens and pistils to group plants into twenty-four classes which in turn are divided into orders, genera and species.

In his publications, Linnaeus provided a concise, usable survey of all the world's plants and animals as then known, about 7,700 species of plants and 4,400 species of animals. These works helped to establish and standardize the consistent binomial nomenclature for species which he introduced on a world scale for plants in 1753, and for animals in 1758, and which is used today.

His Systema Naturae 10th edition, volume 1(1758), has accordingly been accepted by international agreement as the official starting point for zoological nomenclature. Scientific names published before then have no validity unless adopted by Linnaeus or by later authors. This confers a high scientific importance on the specimens used by Linnaeus for their preparation, many of which are in his personal collections now treasured by the Linnean Society.

He was granted nobility in 1761, becoming Carl von Linné. He continued his work of classification and as a physician, and remained Rector of the University until 1772.

Born This Day: Nicolaus Steno

Jan. 10 – Nov. 26, 1686

Steno (a.k.a. Niels Steensen, or Stensen) was a Danish geologist and anatomist who first made unprecedented discoveries in anatomy, then established some of the most important principles of modern geology. He was Danish royal anatomist for 2 years.

Interested by the characteristics and origins of minerals, rocks, and fossils, he published in Prodromus (1669) the law of superposition (if a series of sedimentary rocks has not been overturned, upper layers are younger and lower layers are older) and the law of original horizontality (although strata may be found dipping steeply, they were initially deposited nearly horizontal.) link

The Origin of Biomineralization

Eve of biomineralization: Controls on skeletal mineralogy. 2008. A. Zhuravlev and R. Wood. Geology 36: 923–926

Abstract: Carbonate mineralogies have oscillated between aragonite and calcite seas through geological time, proposed to be due mainly to secular variation in the magnesium/calcium ratio driven by changing rates of ocean crust production. A quantitative compilation of inorganic and biominerals from the onset of biomineralization (late Ediacaran–Middle Ordovician) reveals a correspondence between seawater chemistry and the first adopted mineralogy of skeletal clades.

Ediacaran–Tommotian skeletons and inorganic precipitates were composed exclusively of aragonite or high-Mg calcite, but these were replaced by low-Mg calcite mineralogies during the early Atdabanian, implying the onset of a calcite sea. This transition is empirically constrained by fluid inclusion data.

Late Atbadanian–Botoman inorganic precipitates returned to aragonite, with high-Mg calcite echinoderms and solitary tabulaconids and massive aragonitic tabulaconids originating during this interval.

Middle Cambrian–Ordovician inorganic precipitates were low-Mg calcite, and the Ordovician radiation in skeletal expression was due mostly to groups with low-Mg calcite mineralogies.

These short-lived transitions can be most parsimoniously explained by minor oscillations of mMg:Ca around ~2 during this period, possibly combined with the progressive onset of greenhouse conditions during the mid-Late Cambrian.

Friday, January 09, 2009

New Cynodont: Protuberum cabralensis

A new traversodontid cynodont (Therapsida, Eucynodontia) from the middle Triassic Santa Maria Formation ofRio Grande do Sul, Brazil. 2008. M. Reichel et al. Palaeontology 52: 229 – 250.

Abstract: Remains of a peculiar traversodontid cynodont, Protuberum cabralensis gen. et sp. nov., are described herein. The material was collected from two outcrops representing the Therapsid Cenozone (Middle Triassic) of the Santa Maria Formation, and consists of a cranium with most of its dentition preserved and an associated postcranial skeleton.

The upper postcanines have two sharp cusps that are connected by a medial crest on unworn postcanines. The specimens possess several autapomorphies, including: (1) presence of thickened bone on the dorsal surface of the skull; (2) thick dorsal ribs, with remarkable processes situated on their dorsal borders that decrease in size distally; and (3) an iliac blade with a series of rugosities along its dorsal border. The lumbar ribs bear overlapping costal plates and have distally projecting rib shafts that differ from the pattern observed in Thrinaxodon, Pascualgnathus and Cynognathus.

Thursday, January 08, 2009

Born This Day: Alfred Russel Wallace

From Today In Science History:

Wallace (Jan. 8, 1823 – Nov. 7, 1913) was a British naturalist and biogeographer. He was the first westerner to describe some of the most interesting natural habitats in the tropics. He is best known for devising a theory of the origin of species through natural selection made independently of Darwin.

Between 1854 and 1862, Wallace assembled evidence of natural selection in the Malay Archipelago, sending his conclusions to Darwin in England. Their findings were jointly presented to the Linnaean Society in 1858. Wallace found that Australian species were more primitive, in evolutionary terms, than those of Asia, and that this reflected the stage at which the two continents had become separated. He proposed an imaginary line (now known as Wallace's line) dividing the fauna of the two regions.

The Alfred Russel Wallace page HERE. More HERE.

Wednesday, January 07, 2009

Dinosaur Provincial Park Advances in 7 Wonders Contest

What's wrong with this picture?
Dinosaur Provincial Park in Alberta, Niagara Falls and Lake Superior will be competing with more than 200 spectacular places around the world in the next phase of a competition to name the New 7 Wonders of Nature, organizers said Wednesday.

The three Canadian entrants were among 261 nominees, a list that includes Mount Everest, the Grand Canyon, and Loch Ness.

Over a billion people are expected to join in internet voting to nominate the 77 semifinalists for the top natural wonders. Votes can be cast until July 7, after which a panel of experts will select 21 finalists to be put to another popular vote, which is expected conclude in 2011.
Great news! Too bad the CBC illustrated the article with my photo (above) showing the excavation of Albertaceratops 150 south of DPP.

Thanks to Lisa (Hi Lisa!) for the heads up on this.

Pterosaurs Cleared For Four-Footed Launch

Comparative evidence for quadrapedal launch in pterosaurs. 2008. M. Habib. Zitteliana

Report suggests that pterosaurs used four legs to launch. Two were ultra-strong wings which, when folded and balanced on a knuckle, served as front “legs” that helped the creature to walk — and leap.
From the press release:

A supersized glitch is inherent in the traditional bipedal launch model, Habib notes: “If a creature takes off like a bird, it should only be able to get as big as the biggest bird.” However, Habib reports that pterosaurs had much stronger “arms” than legs. The reverse is true of birds.

Birds use legs to launch, wings to flap. They don’t get launch power from wings or flight power from legs. In fact, when a bird is aloft, its legs become payload, or cargo. The muscle on the two back limbs that provides the power to launch must be carried and therefore limits size. Released of that handicap by employing all four legs to launch, giant pterosaurs could fly despite the fact that they were roughly the same size and shape as modern-day giraffes.

The wings of these fantastic hairy reptiles propelled the creatures into the air during take-offs that Habib describes as leap-frogging long-jumps. Then, with wings snapping out, off they’d fly.

Using all four legs, it takes less than a second to get off of flat ground, no wind, no cliffs,” he said. “This was a good thing to be able to do if you lived in the late Cretaceous period and there were hungry tyrannosaurs wandering around.”