The Early Evolution of Feathers

The early evolution of feathers: fossil evidence from Cretaceous amber of France. 2008. Vincent Perrichot et al. Proceedings of the Royal Society B. Tuesday, February 19, 2008.

Art © Luis Rey

Abstract: The developmental stages of feathers are of major importance in the evolution of body covering and the origin of avian flight. Until now, there were significant gaps in knowledge of early morphologies in theoretical stages of feathers as well as in palaeontological material. Here we report fossil evidence of an intermediate and critical stage in the incremental evolution of feathers which has been predicted by developmental theories but hitherto undocumented by evidence from both the recent and the fossil records.

Seven feathers have been found in an Early Cretaceous (Late Albian, ca 100Myr) amber of western France, which display a flattened shaft composed by the still distinct and incompletely fused bases of the barbs forming two irregular vanes. Considering their remarkably primitive features, and since recent discoveries have yielded feathers of modern type in some derived theropod dinosaurs, the Albian feathers from France might have been derived either from an early bird or from a non-avian dinosaur.

Watch the animated three-dimensional virtual reconstruction of one fossil feather from Early Cretaceous French amber in phase contrast microtomography showing vanes resulting from the opposed but irregular insertion of barbs on the flattened rachis HERE.

Duelity: Creationism/Darwinism

"Imagine the story of creation shown thru the cold lens of Science, and evolution told as a biblical tale. It’s a head-spinningly complex splitscreen experience and demands repeat viewing."

"Duelity is a split screen animation that tells both sides of the story of Earth's origins in a dizzying and provocative journey through the history and language that marks human thought." The film has been directed by Boca AKA Marcos Ceravolo and Ryan Uhrich, two students of the Vancouver Film School, and written by Lee Henderson. Sound design: James Boatman and Chris Ray. Voice over: Mariem Henaine and Rob Wood.

Watch: Duelity

To watch the two films separately:

"If thou shalt believe the Book of Darwin, t'is billion years after the Big Bang that we behold what the cosmos hath begat: the magma, the terra firma, the creeping beasts and the mankind, whose dolorous and chaotic evolution begat the gift of consciousness."

Watch Duelity: Darwinism

"According to the records of the General Organization of Development (GOD) it took a mere six days to manufacture a fully operational universe, complete with day, night, flora and fauna, and installing Adam as its manager to oversee daily functions on Earth."

Watch Duelity: Creationism

Thanks to NoFatClips

Born This Day: Karl Ernst von Baer

Feb 29, 1792 - Nov 28, 1876

Von Baer was a Prussian-Estonian embryologist who discovered the mammalian egg (1827) and the notochord. He established the new science of comparative embryology alongside comparative anatomy with the publication of two landmark volumes (in 1828 and 1837) covering the range of existing knowledge of the prebirth developments of vertebrates.

He showed that mammalian eggs were not the follicles of the ovary but microscopic particles inside the follicles. He described the development of the embryo from layers of tissue, which he called germ layers, and demonstrated similarities in the embryos of different species of vertebrates.

From Today In Science History

Died This Day: Prof. Thurgood Elson

August 22, 1893 – February 28, 1973

Or at least the actor, Cecil Kellaway, who played him in “The Beast From 20,000 Fathoms” passed away this day in 1973.



For those of you who seen the film, Elson was the palaeontologist who went down in the diving bell looking for the beast, but who did not make it back up.

CLICK TO ENLARGE

Since I’m still on the road (today working with the crew from the Univ. of Utah at the CMN in Quebec), this gives me an excuse to point you to this great parody of “The Beast” that you can read the rest of HERE

It’s from Atlas' Crazy #2, 1954 with artwork is by Joe Maneely, a great cartoonist who seemed to work almost exclusively for Atlas before his accidental death.

When Life Took Its First Breath

Pulsed oxidation and biological evolution in the Ediacaran Doushantuo Formation. 2008. K. A. McFadden et al. PNAS 105: 3197-3202 (the article is not up yet as of this posting)

The photo (field of view about 0.15 millimeter in width) is of an exceptionally preserved eukaryotic fossil from the Doushantuo Fm (635–551 million years old) in South China. Photo: Shuhai Xiao

From the press release:

The rise of oxygen and the oxidation of deep oceans between 635 and 551 million years ago may have had an impact on the increase and spread of the earliest complex life, including animals.

The atmosphere had almost no oxygen until 2.5 billion years ago, and it was not until about 600 million years ago when the atmospheric oxygen level rose to a fraction of modern levels. For a long time, geologists and evolutionary biologists have speculated that the rise of the breathing gas and subsequent oxygenation of the deep oceans are intimately tied to the evolution of modern biological systems.

To test the interaction between biological evolution and environmental change, an international team examined changes in the geochemistry and fossil distribution of 635- to 551-million-year old sediments preserved in the Doushantuo Formation in the Yangtze Gorges area of South China.

The stratigraphic pattern of carbon isotope abundances suggested to these researchers that the ocean, which largely lacked oxygen before animals arrived on the scene, was aerated by two discrete pulses of oxygen.

“The first pulse apparently had little impact on a large organic carbon reservoir in the deep ocean, but did spark changes in microscopic life forms,” McFadden said. The second event, which occurred around 550 million years ago, however, resulted in the reduction of the organic carbon reservoir, indicating that the ocean became fully oxidizing just before the evolution and diversification of many of Earth’s earliest animals,” she said.

Following this second oxidation event, between 550 and 542 million years ago, there was a worldwide increase of Ediacara organisms, complex macroscopic life forms, an event recently dubbed as the Avalon Explosion. “This was when we see the first burrowing animals and the first animals to form external skeletons, or shells.

The triggers for the oxidation events remain elusive, however. “These events recorded in the ocean were probably related to oxygen in the atmosphere reacting with sediments on land,” McFadden said. “Weathering of rocks and soils on the continents would result in the release of certain dissolved ions, such as sulfate, into rivers. These would then be transported to the sea where they might be used by bacteria to oxidize the organic carbon pool in the deep oceans,” she said.

The Organic Nature of Stromatolites

Microbially influenced formation of 2,724- million- year-old stromatolites. 2008. K. Lepot et al. Nature Geoscience 1: 118-121

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Abstract: Laminated accretionary carbonate structures known as stromatolites are a prominent feature of the sedimentary record over the past 3,500 Myr. The macroscopic similarity to modern microbial structures has led to the inference that these structures represent evidence of ancient life. However, as Archaean stromatolites only rarely contain microfossils, the possibility of abiogenic origins has been raised.

Here, we present the results of nanoscale studies of the 2,724-Myr-old stromatolites from the Tumbiana Formation (Fortescue Group, Australia) showing organic globule clusters within the thin layers of the stromatolites. Aragonite nanocrystals are also closely associated with the organic globules, a combination that is remarkably similar to the organo-mineral building blocks of modern stromatolites. Our results support microbial mediation for the formation of the Tumbiana stromatolites, and extend the geologic record of primary aragonite by more than 2,300 Myr.

When The Ice Levee Breaks

The subglacial origin of the Lake Agassiz–Ojibway final outburst flood. 2008. P. Lajeunesse and G. St-Onge. Nature Geoscience, published online 24 February.

From Physorg.com:

During the last ice age, the Laurentide Ice Sheet once covered most of Canada and parts of the northern United States with a frozen crust that in some places was three kilometres (two miles) thick. As the temperature gradually rose some 10,000 years ago, the ice receded, gouging out the hollows that would be called the Great Lakes.

Beneath the ice's thinning surface, an extraordinary mass of water built up -- the glacial lake Agassiz-Ojibway, a body so vast that it covered parts of Manitoba, Saskatchewan, North Dakota, Ontario and Minnesota.

And then, around 8,200 years ago, Agassiz-Ojibway massively drained, sending a flow of water into the Hudson Strait and into the Labrador Sea that was 15 times greater than the present discharge of the Amazon River.

The influx of freshwater into the North Atlantic reduced ocean salinity so much that this braked the transport of heat flowing from the tropics to temperate regions. Temperatures dropped by more than three degrees Celsius in Western Europe for 200-400 years -- a mini-Ice Age in itself.

Abstarct: Deglaciation of North America resulted in the development of the ice-dammed lake Agassiz–Ojibway along the southern margin of the Laurentide Ice Sheet and its catastrophic northward drainage 8.47 kyr ago. This sudden outburst of fresh water may have weakened the Atlantic ocean overturning circulation and triggered the cold event that occurred 8.2 kyr ago.

Geological evidence of this flood has been documented in a red sedimentary bed in cores collected in Hudson Strait and by submarine features in Hudson Bay. However, there have been few constraints on the manner in which the lake drained: for example, by flow over the ice sheet or beneath it, in one or several pulses and where the flood routes were located.

Here we present seafloor images obtained using multibeam sonar, which reveal that the outburst flood displaced icebergs to produce arcuate (arc-shaped) scours on the seafloor with a dominant east-northeast–west-southwest orientation. The flood also produced sandwaves in areas unaffected by the arcuate scours, indicating they were protected from iceberg scouring by overlying ice during the event. We suggest that these sandwaves, along with submarine channels inferred from the data, indicate that Laurentide ice was lifted buoyantly, enabling the flood to traverse southern Hudson Bay under the ice sheet.

Another Frank Cho Dino Strip

Click to Enlarge (a bit)
Today's rerun of an old Frank Cho Liberty Meadows strip.

New Fossil Sea Birds From New Zealand

Photo courtesy Jeffrey D. Stilwell

From National Geographic News:

The oldest known bird fossils from New Zealand were recently unearthed along a remote stretch of beach on the Chatham Islands, researchers announced. The fossils represent possibly four new species of seabirds dating back to the late Cretaceous period, around 65 million years ago.

Other remains from the same blocks of fossil-laden sandstone suggest that the birds co-existed with marine and terrestrial dinosaurs. "This is New Zealand's oldest fossil aviary, and it has implications for the origin of modern seabirds," said excavation leader Jeffrey Stilwell of Monash University in Australia.

Stilwell found the fossil trove along a 1.2-mile (2-kilometer) stretch of rugged shoreline on the main Chatham Island, which sits more than 500 miles (800 kilometers) east of Christchurch. Storms had washed sand away from a rocky platform on Maunganui Beach, revealing a wealth of bones from the Cretaceous.

Died This Day: Sir Charles Lyell

Nov. 14, 1797 - Feb. 22, 1875



From Minnesota State University at Mankato comes this excellent bio on Lyell:

Sir Charles Lyell attended Oxford University at age 19. Lyell's father was an active naturalist. Lyell had access to an elaborate library including subjects such as Geology.

When Lyell was at Oxford, his interests were mathematics, classics, law and geology. He attended a lecture by William Buckland that triggered his enthusiasm for geology. Lyell originally started his career as a lawyer, but later turned to geology. He became an author of The Geological Evidence of the Antiquity of Man in 1863 and Principles of Geology. Lyell argued in this book that, at the time, presently observable geological processes were adequate to explain geological history. He thought the action of the rain, sea, volcanoes and earthquakes explained the geological history of more ancient times.

Lyell rebelled against the prevailing theories of geology of the time. He thought the theories were biased, based on the interpretation of Genesis. He thought it would be more practical to exclude sudden geological catastrophes to vouch for fossil remains of extinct species and believed it was necessary to create a vast time scale for Earth's history. This concept was called Uniformitarianism. The second edition of Principles of Geology introduced new ideas regarding metamorphic rocks. It described rock changes due to high temperature in sedimentary rocks adjacent to igneous rocks. His third volume dealt with paleontology and stratigraphy. Lyell stressed that the antiquity of human species was far beyond the accepted theories of that time.

Charles Darwin became his dear friend and correspondent. Darwin is quoted saying, "The greatest merit of the Principles was that it altered the whole tone of one's mind, and therefore that, when seeing a thing never seen by Lyell, one yet saw it through his eyes."

Image from King’s College London.

New 'TOR' from Joe Kubert

Click to Enlarge

At 81 yrs, Joe Kubert is one of the real grand masters of comic book illustration and still producing exceptional work. Later this year Joe will be bringing back his classic character, Tor, in a limited series.

FYI, I'll be away for the next 10 days. As usual, my access to the internet will be limited but I'll post when I can.

Behold! Beelzebufo!

A giant frog with South American affinities from the Late Cretaceous of Madagascar. 2008. S. Evans et al. PNAS, Published online on February 19, 2008.


Illustration by Luci Betti-Nash, courtesy Stony Brook University

An illustration depicts the ancient frog species Beelzebufo, or "devil frog," staring down the largest frog species living in Madagascar today. A pencil is included for scale. Scientists recently identified Beelzebufo from a 70-million-year-old fossil found in Madagascar, and think it may have been the largest frog that ever lived.

That big frog story

Born This Day: William Diller Matthew

Feb. 19, 1871 – Sept. 24, 1930

Matthew was a superb mammalian paleontologist and important biogeographic theorist, and also G. G. Simpson's primary mentor. Matthew published voluminiously on the fossil record of mammals and advocated a fully modern approach to taxonomy that emphasized tying scientific names to natural biological populations. His 1930 paper gives a clear statement of this position.

Matthew's key biogeographic theory was that waves of faunal migration repeatedly went from the northern continents southwards. This theory, which had obvious racial and political overtones, was justified by a "stabilist" view of paleogeography (i.e., that the continents had never moved from their modern positions), and by evidence from the relatively young fossil record of mammals, at the expense of other data that would have shown the more ancient interconnections among South America, Africa, India, and Australia. Remarkably, Matthew remained a Darwinian despite working for the autocratic orthogeneticist H. F. Osborn for three decades.

Info from HERE. Image from HERE.

Born This Day: Sven Anders Hedin

Feb. 19,1865 - Nov. 26, 1952

Hedin was a Swedish explorer and geographer, born in Stockholm, who led four multi-year expeditions into Central Asia between 1897 and 1935. Although not as well known as Roy Chapman Andrews his work in the regions revealed a wealth of cultural, archaeological and palaeontological wonders.

During his first major Asian expedition, he crossed the Pamirs, charted Lop Nor (Lake) in China, and finally arrived at Beijing. He then journeyed to Tibet by way of Mongolia, Siberia, and the Gobi Desert. Hedin explored Tibet and Xinjiang (Sinkiang), identified the sources of the Brahmaputra, Indus, and Sutlej rivers, and, in 1906, explored and named the Trans-Himalayas. In 1927 Hedin led an expedition of Chinese and Swedish scientists into Central Asia.

He wrote extensively about his adventures (e.g., Across the Gobi Desert, The Conquest of Tibet (1935), My Life as an Explorer (1926)) and they make for engaging and fascinating reading for anyone interested in the early days of exploring Central Asia. link

An excellent summary of Hedin’s life and expeditions into Central Asia can be found at the IDP News Archives image

Born This Day: Sir Roderick Impey Murchison

Feb. 19, 1792 - Oct. 22, 1871

Murchison was a Scottish geologist who first differentiated the Silurian strata in the geologic sequence of Early Paleozoic strata (408-540 million years old). He believed in fossils as primary criteria. In 1831, he began researching the previously geologically unknown graywacke rocks of the Lower Paleozoic, found underlying the Old Red Sandstone in parts of Wales, which culminated in his major work the Silurian System (1839).

An eurypterid, a prehistoric sea scorpion from PBS.org.

Murchison named the Silurian after an ancient British tribe that inhabited South Wales. He established the Devonian working with Adam Sedgwick (1839). He named the Permian (1841) after the Perm province in Russia where he made a geological survey in 1840-45. link

Carnegie Museum Dino Hall

I had a great time at the Carnegie Museum in Pittsburgh this past weekend. Curator Matt Lamanna and his fiancé Mandi were great hosts, so thanks to everyone at the CM for organizing my talk on Saturday afternoon and to everyone who came out to listen.

Above are a few photos of the wonderful new dinosaur hall that Matt et al. put together. It’s a must see for anyone who can get there so I’ve resisted posting any of the big ‘overview’ photos that I took. Note: their new T. rex gallery will be open shortly.


Even the airport as a T.rex – this is a copy of MOR 555 (I think).

Born 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

Born This Day: Ernst Heinrich August Haeckel

Feb, 16, 1834 - Aug. 9, 1919.

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Haeckel was a German zoologist and evolutionist who was a strong proponent of Darwinism and proposed new notions of the evolutionary descent of man. He coined many words commonly used by biologists today, such as phylum, phylogeny, and ecology.

He is noted for the book, The evolution of man: a popular exposition of the principal points of human ontogeny and phylogeny link



Robert Seidel, the man behind the work of 2minds has created a wonderfully lush new piece designed specifically to be projected onto the Phyletic Museum in Jena, Germany for its 100th anniversary.

New Bill Stout Murals at SDNHM

Click to Enlarge

The San Diego Natural History Museum has unveiled a series of new murals by William Stout. Go HERE to see more images. Bill tells me that a book about the production of these murals is in the works from Flesk Publications.

FYI, I'm off to the Carneige Museum in Pittsburgh tomorrow for a free (with admission) public lecture on horned-dinos. Drop by if you're in the area.

New African Theropods

Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger. 2008. P.C. Sereno and S.L. Brusatte Acta Palaeontologica Polonica 53:15-46.

Kryptops

From the press release:

Two new 110 million-year-old dinosaurs unearthed in the Sahara Desert highlight the unusual meat-eaters that prowled southern continents during the Cretaceous Period. Named Kryptops and Eocarcharia the fossils were discovered in 2000.

Short-snouted Kryptops palaios, or “old hidden face,” was so named for the horny covering that appears to have covered nearly all of its face. “A fast, two-legged hyena gnawing and pulling apart a carcass,” remarked even Brusatte, “is how we might best imagine Kryptops’ dining habits.” Like later members of its group (called abelisaurids) in South America and India, Kryptops had short, armored jaws with small teeth that would have been better at gobbling guts and gnawing on carcasses than snapping at live prey. About 25 feet in length, Kryptops was a voracious meat-eater.

Eocarcharia, reconstructions ©Todd Marshall, courtesy of Project Exploration

A similar-sized contemporary, Eocarcharia dinops, or “fierce-eyed dawn shark,” was so named for its blade-shaped teeth and prominent bony eyebrow. Unlike Kryptops, its teeth were designed for disabling live prey and severing body parts. Eocarcharia and kin (called carcharodontosaurids) gave rise to the largest predators on southern continents, matching or exceeding Tyrannosaurus in size. Eocarcharia’s brow was swollen into a massive band of bone, giving it a menacing glare.

They preyed upon the ground-grubbing, long-necked plant-eater Nigersaurus and lived alongside the enormous extinct crocodilian nicknamed “SuperCroc” (Sarcosuchus). Then, the African continent was part of Gondwana and just beginning to free itself of its land connection to South America.

CLICK TO ENLARGE

Velafrons coahuilensis, New Duck-Billed Dino from Mexico

Velafrons coahuilensi reconstruction courtesy of Gaston Design, Inc.

From the press release:

The 72 million year old duck-billed dinosaur, Velafrons coahuilensis, was collected the state of Coahuila in north-central Mexico by a joint team from the Utah Museum of Natural History, the Utah Geological Survey, the Coordinacion de Paleontologia, Secretaria de Educacion y Cultura de Coahuila the Museo del Desierto,; and the Royal Tyrrell Museum. The species was announced in the December edition of the Journal of Vertebrate Paleontology.

Based on the development of several bony features on the skull and skeleton, the scientists believe that this animal was still a youngster at the time of death. Nevertheless, although not yet fully grown, Velafrons would have been on the order of 25 feet long, suggesting an impressive adult size of 30 feet to 35 feet.

The creature comes from a rock unit known as the Cerro del Pueblo Formation, which dates to around 71.5 million to 72.5 million years ago. The skeleton was discovered in the early 1990s on the outskirts of a small town called Rincon Colorado, about 27 miles west of the city of Saltillo.

In addition to Velafrons, the most recent expeditions recovered remains of a second kind of duck-bill dinosaur, as well as a plant-eating horned dinosaur. The Cerro del Pueblo Formation has also yielded remains of large and small carnivores, including large tyrannosaurs, and more diminutive Velociraptor-like predators. As well as an abundance of fossilized bones, researchers discovered the largest assemblage of dinosaur track ways known from Mexico.

Nemicolopterus crypticus, A New Arboreal Pterosaur

Discovery of a rare arboreal forest-dwelling flying reptile (Pterosauria, Pterodactyloidea) from China 2008. X. Wang et al. PNAS 105: 1983-1987; published online before print

Art by Michael Skrepnick

Abstract: A previously undescribed toothless flying reptile from northeastern China, Nemicolopterus crypticus gen. et sp. nov., was discovered in the lacustrine sediments of the Early Cretaceous Jiufotang Formation, western Liaoning, China. The specimen consists of an almost complete articulated skeleton (IVPP V14377) and, despite representing an immature individual, based on the ossification of the skeleton, it is not a hatchling or newborn, making it one of the smallest pterosaurs known so far (wing span 250 mm).

It can be distinguished from all other pterosaurs by the presence of a short medial nasal process, an inverted "knife-shaped" deltopectoral crest of the humerus, and the presence of a well developed posterior process on the femur above the articulation with the tibia. It further shows the penultimate phalanges of the foot curved in a degree not reported in any pterosaur before, strongly indicating that it had an arboreal lifestyle, more than any other pterodactyloid pterosaur known so far.

It is the sister-group of the Ornithocheiroidea and indicates that derived pterosaurs, including some gigantic forms of the Late Cretaceous with wingspans of >6 m, are closely related to small arboreal toothless creatures that likely were living in the canopies of the ancient forests feeding on insects.

One Step Beyond...Invertebrates!

MicroRNAs and the advent of vertebrate morphological complexity. 2008. A.M. Heimberg, et al.PNAS., published on-line Feb 2008.

Some vertebrates are more evolved than others...

From the press release:

Researchers have traced the beginnings of complex vertebrates life to microRNA. These tiny molecules only recently discovered reside within what has usually been considered junk DNA. . They are hugely diverse in even the most lowly of vertebrates, but relatively few are found in the genomes of our invertebrate relatives.

The team studied the genomics of primitive living fishes, such as sharks and lampreys, and their spineless relatives, like the sea squirt. By reconstructing the acquisition history of microRNAs shared between human and mice, the researchers determined that the highest rate of microRNA innovation in the vertebrate lineage occurred before the divergence between the living jawless fishes like the lamprey and the jawed fishes like the shark, but after the divergence of vertebrates from their invertebrate chordate relatives, such as the sea squirt.

“Most of these new genes are required for the growth of organs that are unique to vertebrates, such as the liver, pancreas and brain. Therefore, the origin of vertebrates and the origin of these genes is no coincidence.”

Born This Day: Charles Darwin

Feb. 12, 1809 – April 19, 1882



From the AMNH introduction to their exhibit on Darwin:

Keenly observing nature in all its forms—from fossil sloths to mockingbirds, primroses to children—Darwin saw that we all are related. Every living thing shares an ancestry, he concluded, and the vast diversity of life on Earth results from processes at work over millions of years and still at work today. Darwin's explanation for this great unfolding of life through time—the theory of evolution by natural selection—transformed our understanding of the living world, much as the ideas of Galileo, Newton and Einstein revolutionized our understanding of the physical universe.

Darwin's theory of evolution by natural selection underlies all modern biology. It enables us to decipher our genes and fight viruses, and to understand Earth's fossil record and rich biodiversity. Simple yet at times controversial, misunderstood and misused for social goals, the theory remains unchallenged as the central concept of biology. Charles Darwin, reluctant revolutionary, profoundly altered our view of the natural world and our place in it.

The American Museum of Natural History's video on Darwin.
Darwin's biography from the British Library.
Learn more about Darwin Days.
The Darwin Awards.

Born This Day: Barnum Brown

Feb. 12, 1873 – Feb. 5, 1963

Photo © AMNH

From the AMNH bio:

The greatest dinosaur hunter of the twentieth century was Barnum Brown, who began his career at the American Museum of Natural History in 1897 as an assistant to Henry Fairfield Osborn. Brown traveled all over the world collecting dinosaurs and fossil mammals. Some consider him to be the last of the great dinosaur hunters.

Brown was always impeccably dressed, often wearing a tie and topcoat even in the field. He was a shrewd "horse trader" when it came to wheeling and dealing for fossil specimens. Many of Brown's greatest discoveries, including the first specimens of Tyrannosaurus rex ever found, are displayed in the Museum's Dinosaur Halls.

Komodo Hatchlings vs. Juveniles

Ontogenetic differences in the spatial ecology of immature Komodo dragons. 2008. M. J. Imansyah et al. Journal of Zoology 274: 107–115.

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Abstract: The early life-history stages of reptiles are extremely important to an individual's fitness, but in an ecological sense, among the most difficult to observe. Here, we used radio-tracking techniques to describe the differences in movement patterns, habitat use and home range between hatchling and juvenile Komodo dragons Varanus komodoensis on Komodo Island, Indonesia.

The movement of hatchlings from their nests was largely linear and suggested a natal dispersal event. The movement patterns of juvenile Komodo dragons exhibited a greater spatial overlap than hatchlings, indicating greater site fidelity and thus use of a more defined activity area. The rates of daily movement were significantly less for hatchlings compared with juvenile dragons. The activity areas of hatchlings were significantly smaller than juvenile dragons. Both age classes preferred utilizing dry monsoon forest compared with other habitat types.

Hatchlings were predominantly arboreal compared with juveniles and the degree of arboreal activity was strongly correlated with an individual's size. These distinct differences in spatial ecology between immature life-history stages suggest that different selection pressures may affect different size classes of Komodo dragons.

Nice to see some empirical data for how young big reptiles differ in habitat use.

Body Size Evolution in Mesozoic Birds

Body size evolution in Mesozoic birds. 2008. D.W.E.Hone et al. Journal of Evolutionary Biology 21: 618-624.

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Abstract: The tendency for the mean body size of taxa within a clade to increase through evolution (Cope’s Rule) has been demonstrated in a number of terrestrial vertebrate groups. However, because avian body size is strongly constrained by flight, any increase in size during the evolution of this lineage should be limited – there is a maximum size that can be attained by a bird for it to be able to get off the ground.

Contrary to previous interpretations of early avian evolution, we demonstrate an overall increase in body size across Jurassic and Cretaceous flying birds: taxon body size increases from the earliest Jurassic through to the end of the Cretaceous, across a time span of 70 Myr. Although evidence is limited that this change is directional, it is certainly nonrandom. Relative size increase occurred presumably as the result of an increase in variance as the avian clade diversified after the origin of flight: a progression towards larger body size is seen clearly within the clades Pygostylia and Ornithothoraces.

In contrast, a decrease in body size characterizes the most crownward lineage Ornithuromorpha, the clade that includes all extant taxa, and potentially may explain the survival of these birds across the Cretaceous-Palaeogene boundary. As in all other dinosaurs, counter selection for small size is seen in some clades, whereas body size is increasing overall.

10,000 B.C.

watch the trailer
I wonder what inspired the poster?


© Frank Frazetta
But Frank was looking at this:

Art by Charles Knight

Hopefully the prehistoric creatures will at least be worth watching.

Pygmy Dino Inhabited UK Tropical Islands

The age, fauna and palaeoenvironment of the Late Triassic fissure deposits of Tytherington, South Gloucestershire, UK. 2008. D. I. Whiteside and J. E. A. Marshall. Geoogical Magazine, vol 145: 105-147.

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From the press release:

The celebrated Bristol, UK, dinosaur, Thecodontosaurus, has now been shown to live on subtropical islands around Bristol, instead of in a desert on the mainland as previously thought. This new research could explain the dinosaur's small size (2 m) in relation to its giant (10 m) mainland equivalent, Plateosaurus. Like many species trapped on small islands, such as the 'hobbit' Homo floresiensis of Flores and pygmy elephants on Malta, the Bristol Dinosaur may have been subjected to island dwarfing.

Geological mapping indicates that the islands were quite small in size and, judging by abundant remains of fossil charcoal, were often swept by fires. Thus the pygmy Bristol Dinosaur may have met its death in a wildfire.

Thecodontosaurus is one of the earliest named dinosaurs. Its bones were originally found near what is now Bristol Zoo in 1834 - some time before dinosaurs were recognised as a group. In 1975, the remains of at least 11 other individual dinosaurs were uncovered in a quarry at Tytherington, north of Bristol.

Microscopic study of marine algae and fossil pollen shows that, rather than inhabiting the arid uplands of the late Triassic Period, the dinosaurs lived just before the Jurassic Period in a series of lushly vegetated islands around Bristol, the outlines of which can still be seen today in the shape of the land.

Died This Day: Mendel's First Paper

In 1865, Gregor Mendel, who first discovered the laws of genetics, read his first scientific paper to the Brünn Society for the study of Natural Sciences in Moravia (published 1866).

He described his investigations with pea plants. Although he sent 40 reprints of his article to prominent biologists throughout Europe, including Darwin, only one was interested enough to reply.

Most of the reprints, including Darwin’s, were discovered later with the pages uncut, meaning they were never read.

Fortunately, 18 years after Mendel's death, three botanists in three different countries researching the laws of inheritance, in spring 1900, came to realize that Mendel had found them first. Mendel was finally acknowledged as a pioneer in the field which became known as genetics. Info from Today In Science History

Read the paper HERE.

Resurrected Proteins Point To Hot Start For Life

Palaeotemperature trend for Precambrian life inferred from resurrected proteins. 2008. Eric A. Gaucher et al. Nature 451: 704-707.

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From the press release:

Using the genetic equivalent of an ancient thermometer, a team of scientists has determined that the Earth endured a massive cooling period between 500 million and 3.5 billion years ago by using reconstructed proteins from ancient bacteria to measure the Earth’s temperature over the ages.

The team wanted to measure Earth’s temperature billions of years ago to learn more about life on Earth during the Precambrian period. But instead of taking the traditional route — analyzing rock formations or measuring isotopes in fossils — they opted to do what they knew best: protein reconstruction.

“We’ve analyzed the temperature stability of proteins inside organisms that were around during those times,” said Omjoy Ganesh, Ph.D., a structural biologist in the UF College of Medicine’s department of biochemistry and molecular biology. “The ancient oceans were warmer. For ocean organisms living during that time to survive, the proteins within them had to be stable at high temperatures.”

After scanning multiple databases, the scientists struck gold with a protein called elongation factor, which helps bacteria string together amino acids to form other proteins. Each bacterial species has a slightly different form of the protein: Bacteria that live in warmer environments have resilient elongation factors, which can withstand high temperatures without melting. The opposite is true for bacteria that live in cold environments.

Armed with information about when bacterial species evolved, the scientists rebuilt 31 elongation factors from 16 ancient species. By comparing the heat sensitivity of the reconstructed proteins, they were able to discern how Earth’s temperature changed over the ages.

“Remarkably, our results are nearly identical to geologic studies that estimate the temperature trend for the ancient ocean over the same time period. The convergence of results from biology and geology show that Earth’s environment has continuously been changing since life began, and life has adapted appropriately to survive,” Gaucher said.

Darwin's Enduring Legacy

For those of you with the proper access, you can read Kevin Padian’s article, “Darwin's enduring legacy”, in the latest issue of Nature.

What Did A Dinosaur Eat?

From the press release:

Take 200 milligrammes of dried and ground Equisetum, ten millilitres of digestive juice from sheep's rumen, a few minerals, carbonate and water. Fill a big glass syringe with the mix, clamp this into a revolving drum and put the whole thing into an incubator, where the brew can rotate slowly. In this way you obtain the artificial 'dinosaur rumen'. With this apparatus (also used as a 'Menke gas production technique' in assessing food for cows) Dr. Jürgen Hummel from the Bonn Institute of Animal Sciences is investigating which plants giant dinosaurs could have lived off more than 100 million years ago. The largest sauropods dinosaurs' with their 70 to 100 tonnes had a mass of ten full grown elephants or more than 1000 average Germans [insert your own joke here].

Martin Sander, the coordinator of the research group 'Biology of the Sauropod Dinosaurs: The Evolution of Gigantism' and Hummel assume that the herbivorous dinosaurs must have had a kind of fermenter, similar to the rumen in cows today.' Almost all existing herbivores digest their food by using bacteria in this way.

Norfolk Island pine or ginkgo leaves stand their ground surprisingly well compared to today's flora. 'The difference is not as great as might be expected,' Jürgen Hummel emphasises. The bacteria digest ginkgo even better than foliage, but they seem to prefer Equisetum most. With it gas production is even higher than with some grasses. Nevertheless, equisetum figures in the diet of comparatively few animals. The reason is that in addition to the toxins present in many modern species it wears down animals teeth too much. 'Equisetum contains a lot of silicates,' Jürgen Hummel says. 'It acts like sand paper.'

However, many dinosaurs did not have any molars at all. They just pulled up their food and gulped it down. The mechanical break-up may have been carried out by a 'gastric mill'. Similar to today's birds, dinosaurs may have swallowed stones with which they ground the food to a paste with their muscular stomach. image

This is published in Proceedings of the Royal Society B and should be on-line soon. It would be great if the people writing the press releases would a) tell you the title of the paper, and b) provide a link. Honestly, how do some of these people keep their jobs?!

When Did Modern Birds Arise?

Strong mitochondrial DNA support for a Cretaceous origin of modern avian lineages. 2008. J. W. Brown et al. BMC Biology 6:6 (open access)



From the press release:

A new analysis offers the strongest molecular evidence yet for an ancient origin of modern birds, suggesting that modern birds arose more than 100 million years ago, not 60 million years ago, as fossils suggest.

"Scientists typically use two sources of information to date biological events: the fossil record, which contains physical remains of ancient organisms, and molecular genetic data," said graduate student Joseph Brown, who is first author on the paper. In the case of modern birds, however, the two approaches have yielded conflicting results, at times leading to heated debates between paleontologists and molecular biologists. Molecular biologists have asserted that the fossil record must be incomplete, while paleontologists have countered that the genetic data must be suspect.

"What my colleagues and I did was apply all of these new methods to the problem of the origin of modern birds, with each method making different assumptions about how mutation rate changes across the tree," Brown said. He hoped the analysis would narrow the gap between fossil and molecular data, but in fact it only reinforced the rock-clock split by underscoring the finding that modern birds arose more than 100 million years ago.

Born This Day: Mary Leakey

Feb. 6, 1913 – Dec. 9, 1996

From the Minnesota State University site:

Mary Douglas Nicol Leakey was in London, England. She meet her future husband, Louis Leakey, when he asked her to illustrate his book, 'Adam’s Ancestors'. Mary and Louis spent from 1935 to 1959 at Olduvai Gorge in the Serengeti Plains of northern Tanzania where they worked to reconstruct many Stone Age cultures dating as far back as 100,000 to two million years ago. They documented stone tools from primitive stone-chopping instruments to multi-purpose hand axes.

In October of 1947, while on Rusinga Island, Mary unearthed a Proconsul africanus skull, the first skull of a fossil ape ever to be found. It was dated to be twenty million years old. An Australopithecus boisei skull was uncovered in 1959. Not long afterwards, a less robust Homo habilis was found. In 1965 the duo uncovered a Homo erectus cranium.

After her husband died in 1972, Mary continued her work at Olduvai and Laetoli. She discovered Homo fossils at Laetoli which were more than 3.75 million years old, fifteen new species and one new genus. From 1978-81 Mary and her staff worked to uncover the Laetoli hominid footprint trail which was left in volcanic ashes 3.6 million years ago.

Image from HERE where you will also find a slightly more colourful account of her life with Louis.

Born This Day: Gideon Mantell

Feb. 3, 1790 – Nov. 10, 1852

Mantell, a physician of Lewes in Sussex in southern England, had for years been collecting fossils in the sandstone of Tilgate forest, and he had discovered bones belonging to three extinct species: a giant crocodile, a plesiosaur, and Buckland's Megalosaurus. But in 1822 he found several teeth that "possessed characters so remarkable" that they had to have come from a fourth and distinct species of Saurian. After consulting numerous experts, Mantell finally recognized that the teeth bore an uncanny resemblance to the teeth of the living iguana, except that they were twenty times larger.
In this paper, the second published description of a dinosaur, he concluded that he had found the teeth of a giant lizard, which he named Iguanodon, or "Iguana-tooth."

Mantell illustrated his announcement with a single lithographed plate. Mantell included at the bottom of the plate a drawing of a recent iguana jaw, which is shown four times natural size, and for further comparison, he added views of the inner and outer surface of a single iguana tooth, "greatly magnified."

The traditional story that Mantell's wife found the first teeth in 1822, while the doctor was visiting a patient, appears, alas, to be unfounded.

Info and plate from HERE.

Early Dino Movie Tie-Ins

Even as far back as "The Lost World", marketers have found a way to make toys to tie in with dinosaur movies. "Twistum" can still be found for the motivated collector.

Montealtosuchus, 80 Million Year Old Croc

The fossil of a prehistoric reptile dubbed Montealtosuchus arrudacamposi was presented to the public for the first time at a news conference in Brazil on January 31, 2008. Photograph by Ricardo Moraes/AP Photo

The 80-million-year-old terrestrial predator could be a "missing link" between prehistoric and modern-day crocodiles, researchers say.

Read the story at National Geographic News.

Hmmm… Did I really say that?