From here
Tuesday, June 30, 2015
Monday, June 29, 2015
Died This Day: Thomas Huxley
From the UC Berkeley Page:
Huxley (May, 4, 1825 - June 29, 1895) was born in Ealing, near London, the seventh of eight children in a family that was none too affluent. At 21, Huxley signed on as assistant surgeon on the H.M.S. Rattlesnake, a Royal Navy frigate assigned to chart the seas around Australia and New Guinea. Huxley collected and studied marine invertebrates, in particular cnidarians,
tunicates, and cephalopod mollusks. After leaving the Navy in 1854, Huxley managed to secure a lectureship at the School of Mines in London.
Huxley was a passionate defender of Darwin's theory -- so passionate that he has been called "Darwin's Bulldog" – and also a great biologist in his own right, who did original research in zoology and paleontology.
He is best known for his famous debate in June 1860, at the British Association meeting at Oxford. His opponent, Archbishop Samuel Wilberforce, was not-so-affectionately known as "Soapy Sam" for his renowned slipperiness in debate. During the debate, Archbishop Wilberforce ridiculed evolution and asked Huxley whether he was descended from an ape on his grandmother's side or his grandfather's. Accounts vary as to exactly what happened next, but according to one telling of the story, Huxley muttered "The Lord hath delivered him into my hands," and then rose to give a brilliant defense of Darwin's theory, concluding with the rejoinder, "I would rather be the offspring of two apes than be a man and afraid to face the truth."
All accounts agree that Huxley trounced Wilberforce in the debate, defending evolution as the best explanation yet advanced for species diversity.
However, Huxley did not blindly follow Darwin's theory, and critiqued it even as he was defending it. In particular, where Darwin had seen evolution and a slow, gradual, continuous process, Huxley thought that an evolving lineage might make rapid jumps, or saltations. As he wrote to Darwin just before publication of the Origin of Species, "You have loaded yourself with an unnecessary difficulty in adopting Natura non facit saltum [Nature does not make leaps] so unreservedly."
Huxley's most famous writing, published in 1863, is Evidence on Man's Place in Nature. This book, published only five years after Darwin's Origin of Species, was a comprehensive review of what was known at the time about primate and human paleontology and ethology. More than that, it was the first attempt to apply evolution explicitly to the human race. Huxley explicitly presented evidence for human evolution.
Huxley founded a remarkable dynasty of English scientists and thinkers. His son Leonard was a noted biographer and "man of letters." Leonard's oldest son Julian was one of the authors of the evolutionary synthesis of the early 20th century; Julian's son Francis became a noted anthropologist. Julian's brother Aldous Huxley was a novelist, screenwriter and essayist; his best-known book is the anti-utopia Brave New World.
Huxley (May, 4, 1825 - June 29, 1895) was born in Ealing, near London, the seventh of eight children in a family that was none too affluent. At 21, Huxley signed on as assistant surgeon on the H.M.S. Rattlesnake, a Royal Navy frigate assigned to chart the seas around Australia and New Guinea. Huxley collected and studied marine invertebrates, in particular cnidarians,
tunicates, and cephalopod mollusks. After leaving the Navy in 1854, Huxley managed to secure a lectureship at the School of Mines in London. Huxley was a passionate defender of Darwin's theory -- so passionate that he has been called "Darwin's Bulldog" – and also a great biologist in his own right, who did original research in zoology and paleontology.
He is best known for his famous debate in June 1860, at the British Association meeting at Oxford. His opponent, Archbishop Samuel Wilberforce, was not-so-affectionately known as "Soapy Sam" for his renowned slipperiness in debate. During the debate, Archbishop Wilberforce ridiculed evolution and asked Huxley whether he was descended from an ape on his grandmother's side or his grandfather's. Accounts vary as to exactly what happened next, but according to one telling of the story, Huxley muttered "The Lord hath delivered him into my hands," and then rose to give a brilliant defense of Darwin's theory, concluding with the rejoinder, "I would rather be the offspring of two apes than be a man and afraid to face the truth."
All accounts agree that Huxley trounced Wilberforce in the debate, defending evolution as the best explanation yet advanced for species diversity.
However, Huxley did not blindly follow Darwin's theory, and critiqued it even as he was defending it. In particular, where Darwin had seen evolution and a slow, gradual, continuous process, Huxley thought that an evolving lineage might make rapid jumps, or saltations. As he wrote to Darwin just before publication of the Origin of Species, "You have loaded yourself with an unnecessary difficulty in adopting Natura non facit saltum [Nature does not make leaps] so unreservedly."
Huxley's most famous writing, published in 1863, is Evidence on Man's Place in Nature. This book, published only five years after Darwin's Origin of Species, was a comprehensive review of what was known at the time about primate and human paleontology and ethology. More than that, it was the first attempt to apply evolution explicitly to the human race. Huxley explicitly presented evidence for human evolution.
Huxley founded a remarkable dynasty of English scientists and thinkers. His son Leonard was a noted biographer and "man of letters." Leonard's oldest son Julian was one of the authors of the evolutionary synthesis of the early 20th century; Julian's son Francis became a noted anthropologist. Julian's brother Aldous Huxley was a novelist, screenwriter and essayist; his best-known book is the anti-utopia Brave New World.
Saturday, June 27, 2015
Friday, June 26, 2015
Hallucigenia’s Head
Hallucigenia’s head and the pharyngeal armature of early ecdysozoans. 2015. Nature
Abstract: The molecularly defined clade Ecdysozoa comprises the panarthropods (Euarthropoda, Onychophora and Tardigrada) and the cycloneuralian worms (Nematoda, Nematomorpha, Priapulida, Loricifera and Kinorhyncha). These disparate phyla are united by their means of moulting, but otherwise share few morphological characters—none of which has a meaningful fossilization potential. As such, the early evolutionary history of the group as a whole is largely uncharted.
Here we redescribe the 508-million-year-old stem-group onychophoran Hallucigenia sparsa from the mid-Cambrian Burgess Shale. We document an elongate head with a pair of simple eyes, a terminal buccal chamber containing a radial array of sclerotized elements, and a differentiated foregut that is lined with acicular teeth. The radial elements and pharyngeal teeth resemble the sclerotized circumoral elements and pharyngeal teeth expressed in tardigrades, stem-group euarthropods and cycloneuralian worms.
Phylogenetic results indicate that equivalent structures characterized the ancestral panarthropod and, seemingly, the ancestral ecdysozoan, demonstrating the deep homology of panarthropod and cycloneuralian mouthparts, and providing an anatomical synapomorphy for the ecdysozoan supergroup.
Illo by Danielle Dufualt
Abstract: The molecularly defined clade Ecdysozoa comprises the panarthropods (Euarthropoda, Onychophora and Tardigrada) and the cycloneuralian worms (Nematoda, Nematomorpha, Priapulida, Loricifera and Kinorhyncha). These disparate phyla are united by their means of moulting, but otherwise share few morphological characters—none of which has a meaningful fossilization potential. As such, the early evolutionary history of the group as a whole is largely uncharted.
Here we redescribe the 508-million-year-old stem-group onychophoran Hallucigenia sparsa from the mid-Cambrian Burgess Shale. We document an elongate head with a pair of simple eyes, a terminal buccal chamber containing a radial array of sclerotized elements, and a differentiated foregut that is lined with acicular teeth. The radial elements and pharyngeal teeth resemble the sclerotized circumoral elements and pharyngeal teeth expressed in tardigrades, stem-group euarthropods and cycloneuralian worms.
Phylogenetic results indicate that equivalent structures characterized the ancestral panarthropod and, seemingly, the ancestral ecdysozoan, demonstrating the deep homology of panarthropod and cycloneuralian mouthparts, and providing an anatomical synapomorphy for the ecdysozoan supergroup.
The topology shown denotes a newly retrieved ‘hallucishaniid’ clade—diagnosed by a swollen head, dorsal spines, and the differentiation of the anterior trunk and trunk appendages—includes luolishaniids, Orstenotubulus (not shown) and Carbotubulus within a paraphyletic ‘Hallucigenia’.
Tuesday, June 23, 2015
Died This Day: William Crawford Williamson - Father of Paleobotany
Williamson (Nov. 24, 1816-June 23, 1895) was an English naturalist who founded modern paleobotany. His father, John Williamson, was a Yorkshire geologist and the friend of William Smith, the father of English geology. Dr. Williamson's first paper (on organic remains in the Lias of Yorkshire) was published in 1834, when he was only 18.. In 1835 he was appointed curator of the Manchester Natural History Museum, a post which he held while pursuing his medical studies. His numerous earlier papers include one of the first memoirs on Foraminifera, a series of papers on the development of the scales and teeth of fishes.
Williamson was one of the oldest Fellows of the Royal Society, having been elected in 1854. He produced 19 memoirs on the "Organization of the Fossil Plants of the Coal-measures" between 1871 and 1893. He was appointed Professor of Natural History and Geology at Owens College, in 1851, and continued to hold the Chair of Botany until 1892. From here
Monday, June 22, 2015
Premiered This Day (1925): The Lost World
The first and greatest of the film versions of Sir Arthur Conan Doyle's classic book.
Starring the great Wallace Beery as Prof. Challenger, with stunning stop-motion animation by Willis O'Brien
Sunday, June 21, 2015
Saturday, June 20, 2015
Friday, June 19, 2015
Thursday, June 18, 2015
Giant 16 Million Year Old Walking Bats Discovered in New Zealand
Miocene Fossils Reveal Ancient Roots for New Zealand’s Endemic Mystacina (Chiroptera) and Its Rainforest Habitat. 2015. PLoS One
The new fossil bat species, Mystacina miocenalis, which lived 16 million years ago, walked on four limbs and was three times larger than today's average bat, have been discovered in New Zealand.
"Our discovery shows for the first time that Mystacina bats have been present in New Zealand for upwards of 16 million years, residing in habitats with very similar plant life and food sources," says Suzanne Hand.
These bats were believed to have an ancient history in New Zealand, but until now, the oldest fossil of a Mystacina bat in New Zealand was from a cave in South Island, dating to 17,500 years ago. This latest discovery forces a rethink of when these peculiar, walking bats first crossed the ditch, arriving from what is present-day Australia. PR
Kamandi by Jack Kirby © DC Comics
The new fossil bat species, Mystacina miocenalis, which lived 16 million years ago, walked on four limbs and was three times larger than today's average bat, have been discovered in New Zealand.
"Our discovery shows for the first time that Mystacina bats have been present in New Zealand for upwards of 16 million years, residing in habitats with very similar plant life and food sources," says Suzanne Hand.
These bats were believed to have an ancient history in New Zealand, but until now, the oldest fossil of a Mystacina bat in New Zealand was from a cave in South Island, dating to 17,500 years ago. This latest discovery forces a rethink of when these peculiar, walking bats first crossed the ditch, arriving from what is present-day Australia. PR
Wednesday, June 17, 2015
Tuesday, June 16, 2015
Born This Day: George Gaylord Simpson
Simpson (June 16, 1902 - October 6, 1984) is known for his contributions to evolutionary theory and to the 
understanding of intercontinental migrations of animal species in past geological times. Simpson specialized in early fossil mammals, leading expeditions on four continents and discovering in 1953 the 50-million-year old fossil skulls of dawn horses in Colorado.
Simpson helped develop the modern biological theory of evolution, drawing on paleontology, genetics, ecology, and natural selection to show that evolution occurs as a result of natural selection operating in response to shifting environmental conditions. He spent most of his career as a paleontologist at the American Museum of Natural History. image. From Today In Science History.
understanding of intercontinental migrations of animal species in past geological times. Simpson specialized in early fossil mammals, leading expeditions on four continents and discovering in 1953 the 50-million-year old fossil skulls of dawn horses in Colorado.Simpson helped develop the modern biological theory of evolution, drawing on paleontology, genetics, ecology, and natural selection to show that evolution occurs as a result of natural selection operating in response to shifting environmental conditions. He spent most of his career as a paleontologist at the American Museum of Natural History. image. From Today In Science History.
Saturday, June 13, 2015
Born This Day: Luis Alvarez
Alverez (June 13, 1911 - Sept. 1, 1988) was an American experimental physicist who was awarded the Nobel Prize for Physics in 1968 for work that included the discovery of many resonance particles --subatomic particles having extremely short lifetimes and occurring only in high-energy nuclear collisions. 
In about 1980 Alvarez (left) helped his son, the geologist Walter Alvarez (right), publicize Walter's discovery of a worldwide layer of clay that has a high iridium content and which occupies rock strata at the geochronological boundary between the Mesozoic and Cenozoic eras; i.e., about 66.4 million years ago.
They postulated that the iridium had been deposited following the impact on Earth of an asteroid or comet and that the catastrophic climatic effects of this massive impact caused the extinction of the dinosaurs. Though initially controversial, this widely publicized theory gradually gained support as the most plausible explanation of the abrupt demise of the dinosaurs.
Read more HERE. Image from HERE.
In about 1980 Alvarez (left) helped his son, the geologist Walter Alvarez (right), publicize Walter's discovery of a worldwide layer of clay that has a high iridium content and which occupies rock strata at the geochronological boundary between the Mesozoic and Cenozoic eras; i.e., about 66.4 million years ago.
They postulated that the iridium had been deposited following the impact on Earth of an asteroid or comet and that the catastrophic climatic effects of this massive impact caused the extinction of the dinosaurs. Though initially controversial, this widely publicized theory gradually gained support as the most plausible explanation of the abrupt demise of the dinosaurs.
Read more HERE. Image from HERE.
Premiered This Day (1958): The Beast From 20,000 Fathoms
Friday, June 12, 2015
Thursday, June 11, 2015
Downsizing Dreadnoughtus?
Downsizing a giant: re-evaluating Dreadnoughtus body mass. 2015. Biology Letters.
Scientists have shown that the most complete giant, 26 metres long sauropod dinosaur, Dreadnoughtus, discovered in South America in 2014, was not as large as previously thought.
To estimate the mass of Dreadnoughtus scientists originally used a scaling equation that predicts body mass based on the size of thigh and arm bones. This method produced a range of estimates with the average being a colossal 60 tonnes.
Now another group of scientists have used a three-dimensional skeletal modelling technique to examine body mass more directly and found that the mass of the Dreadnoughtus was more likely to be between 30 and 40 tonnes, considerably less than originally thought.
Scientists have shown that the most complete giant, 26 metres long sauropod dinosaur, Dreadnoughtus, discovered in South America in 2014, was not as large as previously thought.
To estimate the mass of Dreadnoughtus scientists originally used a scaling equation that predicts body mass based on the size of thigh and arm bones. This method produced a range of estimates with the average being a colossal 60 tonnes.
Now another group of scientists have used a three-dimensional skeletal modelling technique to examine body mass more directly and found that the mass of the Dreadnoughtus was more likely to be between 30 and 40 tonnes, considerably less than originally thought.
Ah yes, the 'digitally dunking a toy model in water to measure displacement' method of estimating mass. I'll stick to the 'mass estimation' technique of Campione, et. al., 2014.
Wednesday, June 10, 2015
Born This Day: E.O.Wilson
Wilson's On Human Nature (1978) won the Pulitzer Prize; Biophilia (1984) suggests that human attraction to other living things is innate; and Consilience (1998) urges wider integration of the sciences. Other books by Wilson are Insect Societies (1971), The Diversity of Life (1992), The Ants, with Bert Hölldobler (1990; Pulitzer Prize), and The Future of Life (2002).
Tuesday, June 09, 2015
Born This Day: William J. Arkell
Arkell (June 9, 1904 - April 18,
1958) was an English paleontologist who was an authority on Jurassic
ammonites and their environments. He wrote 
Jurassic Geology of the World (1956),
which critically reviewed the information dispersed throughout the
world's enormous literature on the world's Jurassic stratigraphy.
He made numerous contributions to knowledge of the Jurassic stratigraphy, and gradually stabilized many stratigraphically significant zonal assemblages. In 1946, his "Standard of the European Jurassic" advocated a commission formulate a code of rules for stratigraphical nomenclature. image From Today In Science History:
Jurassic Geology of the World (1956),
which critically reviewed the information dispersed throughout the
world's enormous literature on the world's Jurassic stratigraphy.He made numerous contributions to knowledge of the Jurassic stratigraphy, and gradually stabilized many stratigraphically significant zonal assemblages. In 1946, his "Standard of the European Jurassic" advocated a commission formulate a code of rules for stratigraphical nomenclature. image From Today In Science History:
Monday, June 08, 2015
Born This Day: Ernest Schoedsack
Cooper and Schoedsack (right)
They are best known for King Kong (1933), which was co-written by Schoedsack's wife, Ruth Rose. He also directed Son of Kong (1933), Dr. Cyclops (1940) and Mighty Joe Young (1949). From TCM.
Died This Day: Ruth Rose
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.
Sunday, June 07, 2015
Saturday, June 06, 2015
The Complex Structure & Function of Triceratops Teeth
Wear biomechanics in the slicing dentition of the giant horned dinosaur Triceratops. 2015. Science Advances.
Modern reptilian teeth are constructed in such a way that they are used mostly for seizing, but not chewing, food. In contrast, the teeth of most herbivorous mammals self-wear with use to create complex file surfaces for mincing plants.
New work shows that Triceratops teeth were made of five layers of tissue. In contrast, herbivorous horse and bison teeth, once considered the most complex ever to evolve, have four layers of tissue. Crocodiles and other reptiles have just two.
A sophisticated three-dimensional model was developed to show how each tissue wore with use in a strategic manner to create a complex surface with a fuller (a recessed area in the middle, much like those seen in fighting knives and swords) on each tooth. This served to reduce friction during biting and promote efficient feeding. PR
Modern reptilian teeth are constructed in such a way that they are used mostly for seizing, but not chewing, food. In contrast, the teeth of most herbivorous mammals self-wear with use to create complex file surfaces for mincing plants.
New work shows that Triceratops teeth were made of five layers of tissue. In contrast, herbivorous horse and bison teeth, once considered the most complex ever to evolve, have four layers of tissue. Crocodiles and other reptiles have just two.
A sophisticated three-dimensional model was developed to show how each tissue wore with use in a strategic manner to create a complex surface with a fuller (a recessed area in the middle, much like those seen in fighting knives and swords) on each tooth. This served to reduce friction during biting and promote efficient feeding. PR
New Evidence For The Oldest Land Vertebrate
The study Oldest Pathology in a Tetrapod Bone Illuminates the Origin of Terrestrial Vertebrates. 2015. Plos One
A 333-million year old broken bone is causing fossil scientists to reconsider the evolution of land-dwelling vertebrate animals.
Analysis of a fractured and partially healed radius (front-leg bone) from Ossinodus pueri, a large, primitive, four-legged (tetrapod), salamander-like animal, found in Queensland, pushes back the date for the origin of demonstrably terrestrial vertebrates by two million years.
"The break was most plausibly caused by a fall on land because such force would be difficult to achieve with the cushioning effect of water.
"Its age raises the possibility that the first animals to emerge from the water to live on land were large tetrapods in Gondwana in the southern hemisphere, rather than smaller species in Europe.
A 333-million year old broken bone is causing fossil scientists to reconsider the evolution of land-dwelling vertebrate animals.
Analysis of a fractured and partially healed radius (front-leg bone) from Ossinodus pueri, a large, primitive, four-legged (tetrapod), salamander-like animal, found in Queensland, pushes back the date for the origin of demonstrably terrestrial vertebrates by two million years.
"The break was most plausibly caused by a fall on land because such force would be difficult to achieve with the cushioning effect of water.
"Its age raises the possibility that the first animals to emerge from the water to live on land were large tetrapods in Gondwana in the southern hemisphere, rather than smaller species in Europe.
Friday, June 05, 2015
Clevosaurus sectumsemper, A New Triassic Lizard
A distinctive Late Triassic microvertebrate fissure fauna and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia) from Woodleaze Quarry, Gloucestershire, UK. 2015. Proceedings of the Geologists' Association
Research by Catherine Klein, an undergraduate in Bristol's School of Earth Sciences, shows that fossils from the previously unstudied Woodleaze Quarry belong to a new species of the 'Gloucester lizard' Clevosaurus (named in 1939 after Clevum, the Latin name for Gloucester).
In the Late Triassic, the hills of the South West of the UK formed an archipelago that was inhabited by small dinosaurs and relatives of the Tuatara, a living fossil from New Zealand.
"The new species, Clevosaurus sectumsemper, probably lived near the edge of one of the ancient archipelago's islands, in a relatively hostile environment. This would explain why nearly all the bones come from one species, and why there is a relatively high occurrence of healed fractures such as one we found in a rib. Possibly the animals were fighting each other due to a limited food source or perhaps they preyed on each other and bones were broken, but some individuals survived and their broken bones healed." PR
Research by Catherine Klein, an undergraduate in Bristol's School of Earth Sciences, shows that fossils from the previously unstudied Woodleaze Quarry belong to a new species of the 'Gloucester lizard' Clevosaurus (named in 1939 after Clevum, the Latin name for Gloucester).
In the Late Triassic, the hills of the South West of the UK formed an archipelago that was inhabited by small dinosaurs and relatives of the Tuatara, a living fossil from New Zealand.
"The new species, Clevosaurus sectumsemper, probably lived near the edge of one of the ancient archipelago's islands, in a relatively hostile environment. This would explain why nearly all the bones come from one species, and why there is a relatively high occurrence of healed fractures such as one we found in a rib. Possibly the animals were fighting each other due to a limited food source or perhaps they preyed on each other and bones were broken, but some individuals survived and their broken bones healed." PR
Thursday, June 04, 2015
An unusual theropod frontal from the Upper Cretaceous of north Patagonia
An unusual theropod frontal from the Upper Cretaceous of north Patagonia. 2015. Alcheringa. Carabajal & Coria
Abstract: We report an isolated left frontal (MCF-PVPH 320) corresponding to a medium-sized theropod dinosaur from the Portezuelo Formation (Coniacian) of northern Patagonia. It shows a unique combination of traits that are not present in any other known Cretaceous theropod from South America.
MCF-PVPH 320 is robust and anteroposteriorly short, with a flat and smooth dorsal surface largely excavated by the supratemporal fossa. Endocranially, the olfactory bulb impression is elongate, and the olfactory tract impression is markedly shortened anteroposteriorly.
MCF-PVPH 320 differs greatly from the frontals of Late Cretaceous theropods, such as abelisaurids, megaraptorines and carcharodontosaurids. In contrast, character states including the thickness of the bone, V-shaped frontoparietal suture, reduced participation on the orbital margin and markedly short olfactory tract impression suggest the presence of an unknown mid-sized to large allosauroid for the Portezuelo Formation
Abstract: We report an isolated left frontal (MCF-PVPH 320) corresponding to a medium-sized theropod dinosaur from the Portezuelo Formation (Coniacian) of northern Patagonia. It shows a unique combination of traits that are not present in any other known Cretaceous theropod from South America.
MCF-PVPH 320 is robust and anteroposteriorly short, with a flat and smooth dorsal surface largely excavated by the supratemporal fossa. Endocranially, the olfactory bulb impression is elongate, and the olfactory tract impression is markedly shortened anteroposteriorly.
MCF-PVPH 320 differs greatly from the frontals of Late Cretaceous theropods, such as abelisaurids, megaraptorines and carcharodontosaurids. In contrast, character states including the thickness of the bone, V-shaped frontoparietal suture, reduced participation on the orbital margin and markedly short olfactory tract impression suggest the presence of an unknown mid-sized to large allosauroid for the Portezuelo Formation
Late Cretaceous Hellboy
Image by Julius Csotonyi
Welcome Regaliceratops to the pantheon of horned-dinosaurs.
Read about it in the Globe and Mail
Recalibrating the First Eukaryotes
Reappraisal of hydrocarbon biomarkers in Archean rocks. 2015. PNAS
Contaminated samples have evidently created some confusion in the timetable of life.
On the basis of ultra-clean analyses, an international team, including scientists from the Max Planck Institute for Biogeochemistry, has disproved supposed evidence that eukaryotes originated 2.5 to 2.8 billion years ago.
In contrast to prokaryotes such as bacteria, eukaryotes have a nucleus. Some researchers thought they had discovered molecular remnants of living organisms in rock samples up to 2.8 billion years old. However, as the current study shows, these molecular traces were introduced by contamination. The oldest evidence for the existence of eukaryotes is now provided by microfossils that are ca. 1.5 billion years old.
Contaminated samples have evidently created some confusion in the timetable of life.
On the basis of ultra-clean analyses, an international team, including scientists from the Max Planck Institute for Biogeochemistry, has disproved supposed evidence that eukaryotes originated 2.5 to 2.8 billion years ago.
In contrast to prokaryotes such as bacteria, eukaryotes have a nucleus. Some researchers thought they had discovered molecular remnants of living organisms in rock samples up to 2.8 billion years old. However, as the current study shows, these molecular traces were introduced by contamination. The oldest evidence for the existence of eukaryotes is now provided by microfossils that are ca. 1.5 billion years old.
Wednesday, June 03, 2015
Which Dinosaurs Had Feathers?
Evolution of dinosaur epidermal structures. 2015. Biology Letters.
A new study suggests that feathers were less prevalent among dinosaurs than previously believed. Scientists examined the fossil record of dinosaur skin and combined this with an evolutionary tree to assess the probability of feathers appearing in different dinosaur groups. This analysis demonstrated that the majority of non-avian dinosaurs were more likely to have scales than to exhibit signs of 'feather-like' structures.
Congrats to Paul, David and Nic on a nice paper!
Read more at: Phys.org
A new study suggests that feathers were less prevalent among dinosaurs than previously believed. Scientists examined the fossil record of dinosaur skin and combined this with an evolutionary tree to assess the probability of feathers appearing in different dinosaur groups. This analysis demonstrated that the majority of non-avian dinosaurs were more likely to have scales than to exhibit signs of 'feather-like' structures.
Congrats to Paul, David and Nic on a nice paper!
Read more at: Phys.org
Visit The Valley of Gwangi Tonight in Cleveland, OH
I'll be hosting a showing (with discussion to follow) of Ray Harryhausen's "The Valley of Gwangi" at the Capitol Theatre here in Cleveland, OH at 7pm tomorrow (Weds.) evening. It's all part of the CMNH's 'Reel Science' series being run in cooperation with the Capitol.
If prompted, I'll tell the story of taking Ray on his first (and only) dinosaur dig.
Come out and bring a friend!
Born This Day: James Hutton
Hutton (June 3, 1726 - March 26, 1797) is considered to be the father of modern geology. He is accredited with proposing that observed geologic processes have been occurring at a uniform rate since the creation of earth, also know as the theory of unconformities. This led to his controversial suggestion that the earth is incredibly old.
Hutton began to notice geologic processes on his land in the 1750’s by following his soil during rainstorms when it would erode into the sea. He also noticed how long the process took and began to apply this idea to other parts of geology. If it took this long for some soil to move a few miles than how long did it take to form the cliffs by the sea? He also took note of other features in the landscape such as angular unconformities. A breakthrough point occurred for Hutton when he found Siccar’s Point. This site shows the build up of sediment over a long period of time as well as other geologic processes. It was this idea of continuous processes that fascinated Hutton for the rest of his life.
Hutton subsequently moved back to Edinburgh, and became very involved with the Royal Society of Edinburgh. In 1785 he had his friend Joseph Black read his lecture on his theories of earth. This was the first time that his full theory had been made public. He was met with much anger and rejection. Even though we take his ideas for granted today, at the time he was presenting this the oldest proposed age of earth was around six thousand years, as laid forth by the church. While he was able to convince a few by showing them prime field examples such as Glen Tilt and Siccar’s Point, for many it remained too radical an idea to consider.
Text modified from HERE. Image from HERE.
Hutton began to notice geologic processes on his land in the 1750’s by following his soil during rainstorms when it would erode into the sea. He also noticed how long the process took and began to apply this idea to other parts of geology. If it took this long for some soil to move a few miles than how long did it take to form the cliffs by the sea? He also took note of other features in the landscape such as angular unconformities. A breakthrough point occurred for Hutton when he found Siccar’s Point. This site shows the build up of sediment over a long period of time as well as other geologic processes. It was this idea of continuous processes that fascinated Hutton for the rest of his life.Hutton subsequently moved back to Edinburgh, and became very involved with the Royal Society of Edinburgh. In 1785 he had his friend Joseph Black read his lecture on his theories of earth. This was the first time that his full theory had been made public. He was met with much anger and rejection. Even though we take his ideas for granted today, at the time he was presenting this the oldest proposed age of earth was around six thousand years, as laid forth by the church. While he was able to convince a few by showing them prime field examples such as Glen Tilt and Siccar’s Point, for many it remained too radical an idea to consider.
Text modified from HERE. Image from HERE.
Tuesday, June 02, 2015
A Mesozoic bird from Gondwana preserving feathers
A Mesozoic bird from Gondwana preserving feathers. 2015. Nature Communications.
Abstract: The fossil record of birds in the Mesozoic of Gondwana is mostly based on isolated and often poorly preserved specimens, none of which has preserved details on feather anatomy.
We provide the description of a fossil bird represented by a skeleton with feathers from the Early Cretaceous of Gondwana (NE Brazil). The specimen sheds light on the homology and 3D structure of the rachis-dominated feathers, previously known from two-dimensional slabs. The rectrices exhibit a row of rounded spots, probably corresponding to some original colour pattern.
The specimen supports the identification of the feather scapus as the rachis, which is notably robust and elliptical in cross-section. In spite of its juvenile nature, the tail plumage resembles the feathering of adult individuals of modern birds.
Documentation of rachis-dominated tail in South American enantiornithines broadens the paleobiogeographic distribution of basal birds with this tail feather morphotype, up to now only reported from China.
Abstract: The fossil record of birds in the Mesozoic of Gondwana is mostly based on isolated and often poorly preserved specimens, none of which has preserved details on feather anatomy.
We provide the description of a fossil bird represented by a skeleton with feathers from the Early Cretaceous of Gondwana (NE Brazil). The specimen sheds light on the homology and 3D structure of the rachis-dominated feathers, previously known from two-dimensional slabs. The rectrices exhibit a row of rounded spots, probably corresponding to some original colour pattern.
The specimen supports the identification of the feather scapus as the rachis, which is notably robust and elliptical in cross-section. In spite of its juvenile nature, the tail plumage resembles the feathering of adult individuals of modern birds.
Documentation of rachis-dominated tail in South American enantiornithines broadens the paleobiogeographic distribution of basal birds with this tail feather morphotype, up to now only reported from China.