I'll be away for most of the next two weeks, helping out with the 'student field workshop' in Dinosaur Provincial Park starting this weekend and doing some filming with the Discovery channel. I doubt that I'll have much access to the 'net but I'll update when I can.
See you in the funny papers!
Wednesday, May 30, 2007
RTMP Ceratopsian Exhibit
Go HERE and click on the the 'webdoc, click to view' beside the ceratopsid photograph to view the slideshow.
Tuesday, May 29, 2007
Hatchling Stegosaurus Footprints
Researchers at the Morrison Natural History Museum have discovered two rare hatchling dinosaur footprints in the foothills west of Denver, near the town of Morrison.
The fossil footprints represent the first hatchling Stegosaurus footprints ever found, according to Dr. Robert T. Bakker, the museum's curator of paleontology. Stegosaurus was first discovered in Morrison in 1877 and is Colorado's state fossil.
The tracks can be eclipsed by a fifty-cent piece, suggesting that hatchling Stegos were about the size of newborn human baby.
"The tracks are so crisply preserved that I can imagine the sound of tiny feet splashing up water when the baby dinosaurs came to this ancient river to drink and cool down," remarks Museum Director Matthew Mossbrucker, who found the tracks.
The fossils will go on permanent display at the Morrison Natural History Museum Memorial Day weekend as part of its annual "Dinosaur Days" event, which runs from 9 a.m. to 5 p.m. Saturday, May 26 through Monday May 28.
To find out more about Dinosaur Days and special events around the new footprints, visit www.mnhm.org.
The fossil footprints represent the first hatchling Stegosaurus footprints ever found, according to Dr. Robert T. Bakker, the museum's curator of paleontology. Stegosaurus was first discovered in Morrison in 1877 and is Colorado's state fossil.
"The tracks are so crisply preserved that I can imagine the sound of tiny feet splashing up water when the baby dinosaurs came to this ancient river to drink and cool down," remarks Museum Director Matthew Mossbrucker, who found the tracks.
The fossils will go on permanent display at the Morrison Natural History Museum Memorial Day weekend as part of its annual "Dinosaur Days" event, which runs from 9 a.m. to 5 p.m. Saturday, May 26 through Monday May 28.
To find out more about Dinosaur Days and special events around the new footprints, visit www.mnhm.org.
Thursday, May 24, 2007
Remembering The War That Time Forgot
I’ll be out of town over the long weekend so postings may be light until Tuesday.
Swimming Dinos?
Were non-avian theropod dinosaurs able to swim? Supportive evidence from an Early Cretaceous trackway, Cameros Basin (La Rioja, Spain). 2007. R. Ezquerra, et al. Geology 35: 507-510.
From the press release:
An extraordinary underwater trackway with 12 consecutive prints provides the most compelling evidence to-date that some dinosaurs were swimmers. The 15m long trackway, located in La Virgen del Campo track site in Spain's Cameros Basin, contains the first long and continuous record of swimming by a non-avian therapod dinosaur.
The trackway from the early Cretaceous 125 million years ago consists of 6 asymmetrical pairs of 2-3 scratch marks each. Each set of scratch marks, preserved in a layer of sandstone, averages approximately 50cm in length and 15cm wide. The spacing between them suggests an underwater stride of 243-271cm.
The S-shaped prints paint a picture of a large floating animal clawing the sediment as it swam in approximately 3.2m of water. Ripple marks on the surface of the site indicate the dinosaur was swimming against a current, struggling to maintain a straight path.
"The dinosaur swam with alternating movements of the two hind limbs, a pelvic paddle swimming motion," said Costeur. "It is a swimming style of amplified walking with movements similar to those used by modern bipeds, including aquatic birds."
From the press release:
An extraordinary underwater trackway with 12 consecutive prints provides the most compelling evidence to-date that some dinosaurs were swimmers. The 15m long trackway, located in La Virgen del Campo track site in Spain's Cameros Basin, contains the first long and continuous record of swimming by a non-avian therapod dinosaur.
The trackway from the early Cretaceous 125 million years ago consists of 6 asymmetrical pairs of 2-3 scratch marks each. Each set of scratch marks, preserved in a layer of sandstone, averages approximately 50cm in length and 15cm wide. The spacing between them suggests an underwater stride of 243-271cm.
The S-shaped prints paint a picture of a large floating animal clawing the sediment as it swam in approximately 3.2m of water. Ripple marks on the surface of the site indicate the dinosaur was swimming against a current, struggling to maintain a straight path.
"The dinosaur swam with alternating movements of the two hind limbs, a pelvic paddle swimming motion," said Costeur. "It is a swimming style of amplified walking with movements similar to those used by modern bipeds, including aquatic birds."
Wednesday, May 23, 2007
Sinosauropteryx Feather Debate Continues
A new Chinese specime indicates that ‘protofeathers’ in the Early Cretaceous theropod dinosaur Sinosauropteryx are degraded collogen fibres. 2007. Lingham-Soliar T., et al. Proc. R. Soc. Lond. B. PDF download
From Nature News.com:
The discovery calls into question the theory that the first feathers evolved not for flight but for insulation, and that they made their first appearance in relatively early dinosaur lineages that later evolved into modern birds. If these dinosaurs didn't have feathers, or feather-like structures, then feathers may have evolved at a later time, and been used for flight right from the start.
The fossil represents a dinosaur called Sinosauropteryx, which lived in the Early Cretaceous period roughly 140 million years ago. The specimen, found in Liaoning Province, China, has distinctive patterns seen in its skin. Previous studies of other related dinosaurs with similar markings have led experts to conclude that these dinosaurs were covered with downy 'protofeathers'.
But Theagarten Lingham-Soliar from the University of KwaZulu-Natal in Durban, South Africa, and his colleagues now say otherwise. Instead, they argue that these structures are degraded remains of collagen fibres, the main connective tissue in animals.
Lingham-Soliar and his colleagues produced high-resolution microscopic images of the fossil that, he says, show that these structures represent degraded soft tissue. The regular pattern of the fibres suggests that Sinosauropteryx had a frill of skin along its neck, back and tail. And the random orientation of some of the fibres, previously attributed to protofeathers, are more likely to indicate breakages in the regular pattern of collagen fibres as the dinosaur decomposed.
Feathery dinosaurs might not have been as common as experts thought, according to researchers who analysed a fossil of a creature previously thought to have feathers, and found instead that it was bald.
From Nature News.com:
The discovery calls into question the theory that the first feathers evolved not for flight but for insulation, and that they made their first appearance in relatively early dinosaur lineages that later evolved into modern birds. If these dinosaurs didn't have feathers, or feather-like structures, then feathers may have evolved at a later time, and been used for flight right from the start.
The fossil represents a dinosaur called Sinosauropteryx, which lived in the Early Cretaceous period roughly 140 million years ago. The specimen, found in Liaoning Province, China, has distinctive patterns seen in its skin. Previous studies of other related dinosaurs with similar markings have led experts to conclude that these dinosaurs were covered with downy 'protofeathers'.
But Theagarten Lingham-Soliar from the University of KwaZulu-Natal in Durban, South Africa, and his colleagues now say otherwise. Instead, they argue that these structures are degraded remains of collagen fibres, the main connective tissue in animals.
Lingham-Soliar and his colleagues produced high-resolution microscopic images of the fossil that, he says, show that these structures represent degraded soft tissue. The regular pattern of the fibres suggests that Sinosauropteryx had a frill of skin along its neck, back and tail. And the random orientation of some of the fibres, previously attributed to protofeathers, are more likely to indicate breakages in the regular pattern of collagen fibres as the dinosaur decomposed.
Evolution of Tetrapod Limbs
An autopodial-like pattern of Hox expression in the fins of a basal actinopterygian fish. 2007. M.C. Davis, et al. Nature 447: 473-476.
Anterior to the left; distal to top. HoxD expression in Polyodon supports the notion that late-phase HoxD expression is primitive to tetrapods and to osteichthyes in general. Red bars denote: a, acquisition of late-phase HoxD expression; b, loss of non-metapterygial radials; c, loss of the dermal fin fold; d, loss of the metapterygium; e, loss of late-phase HoxD expression. Blue cartoons depict conserved late-phase HoxD seen in Polyodon and tetrapods (here represented by the hind limb of the chicken, Gallus).
Abstract: Comparative analyses of Hox gene expression and regulation in teleost fish and tetrapods support the long-entrenched notion that the distal region of tetrapod limbs, containing the wrist, ankle and digits, is an evolutionary novelty.
Data from fossils support the notion that the unique features of tetrapod limbs were assembled over evolutionary time in the paired fins of fish.
The challenge in linking developmental and palaeontological approaches has been that developmental data for fins and limbs compare only highly derived teleosts and tetrapods; what is lacking are data from extant taxa that retain greater portions of the fin skeletal morphology considered primitive to all bony fish. Here, we report on the expression and function of genes implicated in the origin of the autopod in a basal actinopterygian, Polyodon spathula.
Polyodon exhibits a late-phase, inverted collinear expression of 5' HoxD genes, a pattern of expression long considered a developmental hallmark of the autopod and shown in tetrapods to be controlled by a 'digit enhancer' region. These data show that aspects of the development of the autopod are primitive to tetrapods and that the origin of digits entailed the redeployment of ancient patterns of gene activity.
Anterior to the left; distal to top. HoxD expression in Polyodon supports the notion that late-phase HoxD expression is primitive to tetrapods and to osteichthyes in general. Red bars denote: a, acquisition of late-phase HoxD expression; b, loss of non-metapterygial radials; c, loss of the dermal fin fold; d, loss of the metapterygium; e, loss of late-phase HoxD expression. Blue cartoons depict conserved late-phase HoxD seen in Polyodon and tetrapods (here represented by the hind limb of the chicken, Gallus).
Abstract: Comparative analyses of Hox gene expression and regulation in teleost fish and tetrapods support the long-entrenched notion that the distal region of tetrapod limbs, containing the wrist, ankle and digits, is an evolutionary novelty.
Data from fossils support the notion that the unique features of tetrapod limbs were assembled over evolutionary time in the paired fins of fish.
The challenge in linking developmental and palaeontological approaches has been that developmental data for fins and limbs compare only highly derived teleosts and tetrapods; what is lacking are data from extant taxa that retain greater portions of the fin skeletal morphology considered primitive to all bony fish. Here, we report on the expression and function of genes implicated in the origin of the autopod in a basal actinopterygian, Polyodon spathula.
Polyodon exhibits a late-phase, inverted collinear expression of 5' HoxD genes, a pattern of expression long considered a developmental hallmark of the autopod and shown in tetrapods to be controlled by a 'digit enhancer' region. These data show that aspects of the development of the autopod are primitive to tetrapods and that the origin of digits entailed the redeployment of ancient patterns of gene activity.
In The CMNH VP Dept.
Volunteer Katie Russell paints a median dorsal cast of a Dunkleosteous
Senior Project student Ben does data entry
Volunteer Dale (left) & Senior Project Student Michael prep Devonan fish fossils
Technician Gary Jackson preps a sub-adult Centrosaurus skull collected by George Sternberg in 1920 in Dinosaur Provincial Park. The specimen is on loan from the University of Alberta and is being prepped for a project I'm working on with MSC student Caleb Brown at the U of Calgary.
"Synthetic" Evolution In The Lab
Structural Insights into the Evolution of a Non-Biological Protein: Importance of Surface Residues in Protein Fold Optimization. 2007. M.D. Smith, et al. PLOS One 2(5): e467.
The three-dimensional structure (ribbon diagram) of protein DX as a crystallogrpahic dimer. Photo:John Chaput
The building blocks of proteins are 20 different amino acids that are strung together and folded to make the unique globular shape, stability and function of every protein. The mixing and matching of the amino acid chain like numbers in the lottery are what favor the odds in nature of finding just the right combinations to help generate biological diversity.
To select the raw ingredients to create the proteins the researchers began their quest by further evolving a protein that had been previously selected from a pool of random sequences. They started with a small protein stretch 80 amino acids long. This basic protein segment acts as a protein scaffold that can be selected for the ability to strongly clutch its target molecule, ATP.
There was only one problem, the parental protein could bind ATP, but it wasn’t very stable without it. They decided to speed up protein evolution once again by randomly mutating the parental sequence with a selection specially designed to improve protein stability. After subjecting the
protein fragments to several rounds of this selective environmental pressure, only the ‘survival of the fittest’ ATP binding protein fragments remained.
The remaining fragments were identified and amino acid sequences compared with one another. Surprisingly, They had bested nature’s designs, as the test tube derived protein was not only stable, but could bind ATP twice as tight as anything nature had come up with before.
In a surprising result, just two amino acids changes in the protein sequence were found to enhance the binding, solubility and heat stability.
"We have the distinct advantage over nature of being able to freeze the evolution of our lab-evolved proteins at different time points to begin to tease apart this random process and relate it to the final protein function," said Chaput.
The three-dimensional structure (ribbon diagram) of protein DX as a crystallogrpahic dimer. Photo:John Chaput
The building blocks of proteins are 20 different amino acids that are strung together and folded to make the unique globular shape, stability and function of every protein. The mixing and matching of the amino acid chain like numbers in the lottery are what favor the odds in nature of finding just the right combinations to help generate biological diversity.
To select the raw ingredients to create the proteins the researchers began their quest by further evolving a protein that had been previously selected from a pool of random sequences. They started with a small protein stretch 80 amino acids long. This basic protein segment acts as a protein scaffold that can be selected for the ability to strongly clutch its target molecule, ATP.
There was only one problem, the parental protein could bind ATP, but it wasn’t very stable without it. They decided to speed up protein evolution once again by randomly mutating the parental sequence with a selection specially designed to improve protein stability. After subjecting the
protein fragments to several rounds of this selective environmental pressure, only the ‘survival of the fittest’ ATP binding protein fragments remained.The remaining fragments were identified and amino acid sequences compared with one another. Surprisingly, They had bested nature’s designs, as the test tube derived protein was not only stable, but could bind ATP twice as tight as anything nature had come up with before.
In a surprising result, just two amino acids changes in the protein sequence were found to enhance the binding, solubility and heat stability.
"We have the distinct advantage over nature of being able to freeze the evolution of our lab-evolved proteins at different time points to begin to tease apart this random process and relate it to the final protein function," said Chaput.
Born This Day: Carl Linnaeus
Born 23 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.
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.
Tuesday, May 22, 2007
Born This Day: Sir Arthur Conan Doyle
May 22, 1859 – July 7, 1930
From HERE:
Sir Arthur Conan Doyle was a British writer and creator of Sherlock Holmes. He was born in Edinburgh. His father and uncle were both book illustrators and his mother encouraged his son to explore the world of books. Doyle studied at Edinburgh University and in 1884 he married Louise Hawkins. Doyle qualified as doctor in 1885 and practiced medicine as an eye specialist in Hampshire until 1891 when he became a full time writer. Doyle's first novel about Sherlock Holmes,’ A Study in Scarlet’, was published in 1887.
During the South African war (1899-1902) Doyle served for a few months as senior physician at a field hospital, and wrote ‘The War in South Africa’, in which he defended England's policy. When his son Kingsley died from wounds incurred in World War I, the author dedicated himself in spiritualistic studies.
Doyle's stories of Professor George Edward Challenger in ‘The Lost World’ (1912). The model for the professor was William Rutherford, Doyle's teacher from Edinburgh. Doyle's practice, and other experiences, expeditions as ship's surgeon to the Arctic and West Coast of Africa, service in the Boer War, defenses of George Edalji and Oscar Slater, two men wrongly imprisoned, provided much material for his writings.
The Lost World:
From HERE:
Sir Arthur Conan Doyle was a British writer and creator of Sherlock Holmes. He was born in Edinburgh. His father and uncle were both book illustrators and his mother encouraged his son to explore the world of books. Doyle studied at Edinburgh University and in 1884 he married Louise Hawkins. Doyle qualified as doctor in 1885 and practiced medicine as an eye specialist in Hampshire until 1891 when he became a full time writer. Doyle's first novel about Sherlock Holmes,’ A Study in Scarlet’, was published in 1887.
During the South African war (1899-1902) Doyle served for a few months as senior physician at a field hospital, and wrote ‘The War in South Africa’, in which he defended England's policy. When his son Kingsley died from wounds incurred in World War I, the author dedicated himself in spiritualistic studies.
The Lost World:
Born This Day: Oliver Perry Hay
May 22, 1846 – Novemeber 2, 1930
Hay was an American paleontologist whose catalogs of fossil vertebrates greatly organized existing knowledge and became standard references. Hay's primary scientific interest was the study of the Pleistocene vertebrata of North America and he is renowned for his work on skull and brain anatomy. His first major work was his Bibliography and Catalogue of the Fossil Vertebrata of North America (1902), supplemented by two more volumes (1929-30). Hay also wrote on the evidence of early humans in North America. link
Hay was an American paleontologist whose catalogs of fossil vertebrates greatly organized existing knowledge and became standard references. Hay's primary scientific interest was the study of the Pleistocene vertebrata of North America and he is renowned for his work on skull and brain anatomy. His first major work was his Bibliography and Catalogue of the Fossil Vertebrata of North America (1902), supplemented by two more volumes (1929-30). Hay also wrote on the evidence of early humans in North America. link
Monday, May 21, 2007
Born This Day: Mary Anning
21 May 1799 - 9 Mar 1847
From Today in Science History:
Mary was an English fossil collector who made her first significant discovery at the age of 11 or 12 (sources differ on the details),
when she found a complete skeleton of an Ichthyosaurus, from the Jurassic period. The ten-meter (30 feet) long skeleton created a sensation and made her famous.
Anning's determination and keen scientific interest in fossils derived from her father's interest in fossil hunting, and a need for the income derived from them to support her family after his death. in 1810. She sold large fossils to noted paleontologists of the day, and smaller ones to the tourist trade. In 1823, Anning made another great discovery, found the first complete Plesiosaurus.
Later in her life, the Geological Society of London granted Anning an honorary membership.
Listen to an MP3 clip of the Mary Anning song by the Articokes HERE.
From Today in Science History:
Mary was an English fossil collector who made her first significant discovery at the age of 11 or 12 (sources differ on the details),
when she found a complete skeleton of an Ichthyosaurus, from the Jurassic period. The ten-meter (30 feet) long skeleton created a sensation and made her famous. Anning's determination and keen scientific interest in fossils derived from her father's interest in fossil hunting, and a need for the income derived from them to support her family after his death. in 1810. She sold large fossils to noted paleontologists of the day, and smaller ones to the tourist trade. In 1823, Anning made another great discovery, found the first complete Plesiosaurus.
Later in her life, the Geological Society of London granted Anning an honorary membership.
Listen to an MP3 clip of the Mary Anning song by the Articokes HERE.
Sunday, May 20, 2007
Bigger is Smarter
Overall, not relative, brain size predicts intelligence.When it comes to estimating the intelligence of various animal species, it may be as simple measuring overall brain size. In fact, making corrections for a species' body size may be a mistake.
"Scientists have generally assumed that this pattern occurs because larger animals require larger nervous systems to coordinate their larger bodies. But our results suggest a simpler reason: larger species are typically smarter."
The findings imply that a re-evaluation may be in order for many previous studies that have compared brain size across different animal species, including ancestral hominids.
More from our friends over at Atomic Surgery.
Friday, May 18, 2007
Mark Schultz's Who's Who
CLICK TO ENLARGE
Jack Tenrec & Hannah Dunde © Mark Schultz. Krill Stromer © Michael Ryan & Mark Schultz.
If you’re in Des Moines, Iowa, this weekend Mark is making an appearance at a convention there.
T.rex’s Secret ‘Superweapon’
A team of Alberta scientists has solved the mystery of the mightiest dinosaur's devastating bite: a "unique" evolutionary leap in snout construction -- a fused nasal bone -- that turned Tyrannosaurus rex into a "zoological superweapon."From Canada’s Regina-Leader Post:
The find explains how the dinosaur could inflict its monstrous chomp -- the most powerful ever among land creatures -- on spiky Triceratops or other prey without breaking its own teeth, jaws or skull.
"The tyrannosaur had small arms, and could not grab on to its prey," said University of Alberta biologist Eric Snively, whose study on the famously ferocious dinosaur's colossal crunch -- co-authored with physicist Donald Henderson of Alberta's Royal Tyrrell Museum of Paleontology and University of Calgary information technologist Doug Phillips. "So it couldn't afford to be that delicate. It had to bite into bone, and drive its teeth through bone."
Read the complete press release HERE.
After much threatening by the Palaeoblogger, Eric put together a press release on one of his recently published papers that we reported on HERE, and has now got some nice coverage for it.
Here’s a hint for all you soon-to-be/recently graduated Ph.D.’s—write some press releases and get some media coverage of your interesting and very cool work. This is ridiculously easy to do! Talk to your university or museum media relations people and tell them what you’re working on or have published—they are always interested in new stories that will promote your institution (and you). They’ll help you craft a press release and send it out to the wire services. Then sit back and wait for the Cadillacs full of money to roll up to your office door.
Thursday, May 17, 2007
Born This Day: Thomas Davidson
May 17, 1817 – Oct. 14, 1885
Davison was a Scottish naturalist and paleontologist who became known as an authority on brachiopods. His major work, Monograph of British Fossil Brachiopoda, was published by the Palaeontographical Society. Together with supplements, this comprised six quarto volumes with more than 200 plates drawn on stone by the author. Upon his death, he bequeathed his fine collection of recent and fossil brachiopoda to the British Museum.
Davison was a Scottish naturalist and paleontologist who became known as an authority on brachiopods. His major work, Monograph of British Fossil Brachiopoda, was published by the Palaeontographical Society. Together with supplements, this comprised six quarto volumes with more than 200 plates drawn on stone by the author. Upon his death, he bequeathed his fine collection of recent and fossil brachiopoda to the British Museum.
New Aegyptopithecus Skull
A remarkable female cranium of the early Oligocene anthropoid Aegyptopithecus zeuxis (Catarrhini, Propliopithecidae). 2007. E.L.Simons, et at. PNAS Published online before print May 15, 2007.
From the press release:
A reconstruction of the brain of the second and most intact cranium found of Aegyptopithecus zeuxis suggests that the species "had a brain that might have been even smaller than that of a modern lemur's," said Simons. "This means the big-brained monkeys and apes developed their large brains at a later point in time."
Aegyptopithecus' brain is smaller than once thought. "But other features in these skulls, and in many other Aegyptopithecus fossil pieces collected at the Egyptian site over four decades, suggest that this primate was already branching away from its lemurlike ancestry," he said.
"We also find that the visual cortex was large, which means that like many primates, this species likely had very acute vision," he said. "So the visual sense, which is regarded as a very important feature of anthropoids, or higher primates, had already expanded."
The shape of the animal's eye sockets also suggests Aegyptopithecus was active in the daytime, like modern and ancient higher primates. In contrast, many but not all modern prosimians -- the group that includes lemurs -- are active at night, he said.
From the press release:
A reconstruction of the brain of the second and most intact cranium found of Aegyptopithecus zeuxis suggests that the species "had a brain that might have been even smaller than that of a modern lemur's," said Simons. "This means the big-brained monkeys and apes developed their large brains at a later point in time."
Comparison of female (Left) and male (Right) crania of Aegyptopithecus zeuxis, with unassociated mandibles.After comparing the known skulls which are of the same age, Simons and his collaborators concluded that the new one came from a female that might have weighed about five and a half pounds, while the first one was from a male of more than twice that size. This size difference between the Aegyptopithecus genders is comparable to that of gorillas, which genetically are humans' second-closest relatives.
Aegyptopithecus' brain is smaller than once thought. "But other features in these skulls, and in many other Aegyptopithecus fossil pieces collected at the Egyptian site over four decades, suggest that this primate was already branching away from its lemurlike ancestry," he said.
"We also find that the visual cortex was large, which means that like many primates, this species likely had very acute vision," he said. "So the visual sense, which is regarded as a very important feature of anthropoids, or higher primates, had already expanded."
The shape of the animal's eye sockets also suggests Aegyptopithecus was active in the daytime, like modern and ancient higher primates. In contrast, many but not all modern prosimians -- the group that includes lemurs -- are active at night, he said.
Monday, May 14, 2007
New Condorraptor Unearthed
From ZeeNews:
Buneos Aires, May 11: Paleontologists unearthed a flesh-eating dinosaur some 150 million years old in southern Argentina with all its joints in place, the first time such a beast has been dug up so intact, one of the finders told AFP on Friday.
The seven-meter (23-foot) tall, two-legged dinosaur, dubbed Condorraptor, was found fossilized with parts of its jaw and head showing in rock near the village of Cerro Condor in Patagonia, at a site where paleontologists had been working for five years.
"It is an unprecedented discovery. It is the first time in the world that a carnivorous dinosaur of the Middle Jurassic period has been found fully jointed," said Pablo Puerta, a paleontologist at the Egidio Feruglio museum in the town of Trelew.
Working in the southern province of Chubut, the team led by the German dinosaur specialist Oliver Rauhut uncovered the fossil using a giant crane to shift rock.
Puerta said it will take about a year to fully uncover the dinosaur. It could then go on display at the Trelew museum.
Buneos Aires, May 11: Paleontologists unearthed a flesh-eating dinosaur some 150 million years old in southern Argentina with all its joints in place, the first time such a beast has been dug up so intact, one of the finders told AFP on Friday.
The seven-meter (23-foot) tall, two-legged dinosaur, dubbed Condorraptor, was found fossilized with parts of its jaw and head showing in rock near the village of Cerro Condor in Patagonia, at a site where paleontologists had been working for five years.
"It is an unprecedented discovery. It is the first time in the world that a carnivorous dinosaur of the Middle Jurassic period has been found fully jointed," said Pablo Puerta, a paleontologist at the Egidio Feruglio museum in the town of Trelew.
Working in the southern province of Chubut, the team led by the German dinosaur specialist Oliver Rauhut uncovered the fossil using a giant crane to shift rock.
Puerta said it will take about a year to fully uncover the dinosaur. It could then go on display at the Trelew museum.
Note: I'm still on the road for the next few days.
Thursday, May 10, 2007
Born This Day: V.T. Hamlin
One of the first and best of the original newspaper comic strip serials is ALLEY OOP. Created by Vincent T. Hamlin (born 107 years ago today), and first published in 1932, it chronicles the adventures of the an enlightened, but still rough and tumble, caveman from the prehistoric land of Moo. Through the actions of a well-the meaning modern intentor, Doc Wonmug, Alley Oop and his girl friend, Ooola (as in “O-la-la!"), have traveled both time and space getting into and out of adventures with the most colorful characters of history.
Alley Oop is a hold over from the early days of the classic newspaper comics when artistry reined and the beautiful craftmenship of the illustrated strip could fill an entire page. Hamlin retired in 1971 and passed away in 1993. The strip is carried on today by the artist-writer team of Jack and Carole Bender. It continues the bubbly mix of action, heart, humor that Hamblin made the strip noted for.
For more information on this and other strips visit Toonpedia
CMNH Photos
Katie Russell is a John Carroll College work study student who’s been working in my lab for the past two years (although she’s technically volunteering at the moment). She was in the field last week helping to collect more Devonian fish. She’s soon heading back to El Salvador for the summer to take yet more classes and teach at an orphanage.
VP Casting Tech David Chapman recently helped to move a gorilla donated by the Cleveland Zoo into the museum.
A view out of my office. Dr. Joe Keiper (Invert. Zoo) shows off Dr. Joe Hannibal’s (Invert. Paleo) infamous “Warp-o-Meter ©” used to measure warping marble slabs to a visiting class of Kent State students.
Horned Dinosaur Symposium
The 2007 Horned Dinosaur Symposium will be held at the Royal Tyrrell Museum in Alberta, Canada this Sept. 21-23. If you’re interested in attending and/or presenting a paper or poster I’d urge you to sign up quickly as space is limited.
Keynote speakers, Peter Dodson, Catherine Forster, David Eberth will speak on ceratopsian evolution, biology and ecology, and preservation. A published abstract volume, and book presenting the results of the symposium will follow. The symposium is being convened by Donald Brinkman, Brenda Chinnery-Allgeier, Michael Ryan, David Eberth and Philip Currie, and the organizing committee also includes Dennis Braman, François Therrien, Don Henderson, and staff from the Tyrrell Museum.
The Horned Dinosaur Symposium coincides with the opening of a new ceratopsian dinosaur exhibit at the Royal Tyrrell Museum that will feature many new kinds of horned dinosaurs from Alberta. This Symposium will be one of Canada's palaeontological highlights for 2007.
Other significant events associated with the Symposium include:
• Ice-breaker at the Royal Tyrrell Museum held the evening of Friday, September 21.
• Viewing of new specimens, including Dinosaur Provincial Park's newest ceratopsian
• Barbeque at the Royal Tyrrell Museum on Saturday, September 22.
• Post-symposium field trip to Dinosaur Provincial Park, Monday, September 24, 2007 (there is a separate fee for this field trip).
For more information and to registar click HERE
Keynote speakers, Peter Dodson, Catherine Forster, David Eberth will speak on ceratopsian evolution, biology and ecology, and preservation. A published abstract volume, and book presenting the results of the symposium will follow. The symposium is being convened by Donald Brinkman, Brenda Chinnery-Allgeier, Michael Ryan, David Eberth and Philip Currie, and the organizing committee also includes Dennis Braman, François Therrien, Don Henderson, and staff from the Tyrrell Museum.
The Horned Dinosaur Symposium coincides with the opening of a new ceratopsian dinosaur exhibit at the Royal Tyrrell Museum that will feature many new kinds of horned dinosaurs from Alberta. This Symposium will be one of Canada's palaeontological highlights for 2007.
Other significant events associated with the Symposium include:
• Ice-breaker at the Royal Tyrrell Museum held the evening of Friday, September 21.
• Viewing of new specimens, including Dinosaur Provincial Park's newest ceratopsian
• Barbeque at the Royal Tyrrell Museum on Saturday, September 22.
• Post-symposium field trip to Dinosaur Provincial Park, Monday, September 24, 2007 (there is a separate fee for this field trip).
For more information and to registar click HERE
Wednesday, May 09, 2007
The Importance of Sexual Dimorphism
Sexual dimorphism and adaptive radiation in Anolis lizards. 2007. M.A. Butler, et al. Nature 447: 202-205.
Some Caribbean lizards' strong sexual dimorphism allows them to colonize much larger niches and habitats than they might otherwise occupy, allowing males and females to avoid competing with each other for resources and setting the stage for the population as a whole to thrive. The finding suggests sex differences may have fueled the evolutionary flourishing of the Earth's wildly diverse fauna in a way not previously appreciated by scientists.
"We noticed that every well-known adaptive radiation has sexual dimorphism -- such as Hawaiian honeycreepers, Galapagos finches, and African cichlids -- but these radiations are studied in terms of one sex only, usually males. So we asked a simple question: If animals are adapting to their environment, but the sexes are different, does the sexual variation add to diversity? In other words, is it important to consider both sexes? The answer is yes."
The researchers modeled the "morphospace" -- a gauge of ecological niche taking into account such factors as limb length, body length, and mass -- occupied by 15 different anole species. They found that only 14 percent of niches were occupied by both male and female members of the same anole species, compared to 45 percent that were occupied by only females and 36 percent occupied by only males.
Evolutionary biologists attribute sexual dimorphism to three primary causes. Sexual selection, the competition among members of one sex to mate with individuals of the other sex, can occur when members of one sex, usually males, fight with each other for the ability to mate, or when one sex, often females, chooses among members of the other sex. Differing reproductive demands can also fuel sexual dimorphism: Females of some species, for example, must have larger pelvises to allow the birth of large offspring.
"Another explanation is that sexual differences arise so that the sexes can utilize different resources and not compete with each other," Losos says. "In some hummingbirds, for example, the sexes differ in the length of their beaks, allowing each to drink nectar from different flowers. By diverging in their resource use, the population as a whole can reach higher levels."
Presence of ecologically distinct males and females greatly increases a species' nicheFrom the press release:
Some Caribbean lizards' strong sexual dimorphism allows them to colonize much larger niches and habitats than they might otherwise occupy, allowing males and females to avoid competing with each other for resources and setting the stage for the population as a whole to thrive. The finding suggests sex differences may have fueled the evolutionary flourishing of the Earth's wildly diverse fauna in a way not previously appreciated by scientists.
"We noticed that every well-known adaptive radiation has sexual dimorphism -- such as Hawaiian honeycreepers, Galapagos finches, and African cichlids -- but these radiations are studied in terms of one sex only, usually males. So we asked a simple question: If animals are adapting to their environment, but the sexes are different, does the sexual variation add to diversity? In other words, is it important to consider both sexes? The answer is yes."
The researchers modeled the "morphospace" -- a gauge of ecological niche taking into account such factors as limb length, body length, and mass -- occupied by 15 different anole species. They found that only 14 percent of niches were occupied by both male and female members of the same anole species, compared to 45 percent that were occupied by only females and 36 percent occupied by only males.
Evolutionary biologists attribute sexual dimorphism to three primary causes. Sexual selection, the competition among members of one sex to mate with individuals of the other sex, can occur when members of one sex, usually males, fight with each other for the ability to mate, or when one sex, often females, chooses among members of the other sex. Differing reproductive demands can also fuel sexual dimorphism: Females of some species, for example, must have larger pelvises to allow the birth of large offspring.
"Another explanation is that sexual differences arise so that the sexes can utilize different resources and not compete with each other," Losos says. "In some hummingbirds, for example, the sexes differ in the length of their beaks, allowing each to drink nectar from different flowers. By diverging in their resource use, the population as a whole can reach higher levels."
New Siberian Ceratopsian
A ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of west Siberia, Russia and its phylogenetic relationships. 2006. A.O. Averianov, et al. J. Systematic Palaeo. 4: 359-395.
Abstract: Psittacosaurus sibiricus from the Aptian–Albian Ilek Formation at Shestakovo, Kemerovo Province, West Siberia, is represented by two almost complete adult skeletons, several associated groups of bones and numerous isolated bones of individuals ranging from post-hatchling to fully grown animals.
Psittacosaurus sibiricus differs from nine other species of the genus by a unique combination of 32 diagnostic characters, six of which are autapomorphies of the species: small infratemporal fenestra, anteroposteriorly short premaxilla, short medial process of postorbital, deep cleft for qaudratojugal on jugal, extending to the posterior side of jugal horn, angular with prominent tuber and 23 presacrals.
Psittacosaurus sibiricus is the sister species of P. sinensis, with which it shares the prominent pyramidal laterally projecting jugal horn, but more derived than the latter in having more developed palpebral and postorbital horns. The three lateral foramina on the exoccipital/opisthotic are interpreted as exits for cranial nerves X+XI, XII1+2 and XII3, in contrast with previous interpretations. Cranial nerve IX exits the brain cavity through the metotic fissure.
Most Psittacosaurus localities are confined to lacustrine deposits and this animal undoubtedly inhabited areas around the great lakes widely distributed in Central Asia during the Early Cretaceous. The age of the Psittacosaurus biochron is estimated as Hauterivian–Albian.
Abstract: Psittacosaurus sibiricus from the Aptian–Albian Ilek Formation at Shestakovo, Kemerovo Province, West Siberia, is represented by two almost complete adult skeletons, several associated groups of bones and numerous isolated bones of individuals ranging from post-hatchling to fully grown animals.
Psittacosaurus sibiricus differs from nine other species of the genus by a unique combination of 32 diagnostic characters, six of which are autapomorphies of the species: small infratemporal fenestra, anteroposteriorly short premaxilla, short medial process of postorbital, deep cleft for qaudratojugal on jugal, extending to the posterior side of jugal horn, angular with prominent tuber and 23 presacrals.
Psittacosaurus sibiricus is the sister species of P. sinensis, with which it shares the prominent pyramidal laterally projecting jugal horn, but more derived than the latter in having more developed palpebral and postorbital horns. The three lateral foramina on the exoccipital/opisthotic are interpreted as exits for cranial nerves X+XI, XII1+2 and XII3, in contrast with previous interpretations. Cranial nerve IX exits the brain cavity through the metotic fissure.
Most Psittacosaurus localities are confined to lacustrine deposits and this animal undoubtedly inhabited areas around the great lakes widely distributed in Central Asia during the Early Cretaceous. The age of the Psittacosaurus biochron is estimated as Hauterivian–Albian.
I'm busy with work and other projects at the moment, plus my computer has died (this is being typed out on one of the old steam-operated models), so postings will probably be light for the next week.
Saturday, May 05, 2007
Teen Rex
Teen Rex © 2006 Gary Carlson & Chris Ecker
CLICK TO "DINO-SIZE"!
Alas, unlike some years there are no dinosaur-themed comics being given away.
However, if you see this recently released issue of “Teen Rex” you might want to pick it up. It’s a nice pastiche (or ‘mash-up’ as the kids say) of Jack Kirby’s ‘Kamandi’ and ‘Devil Dinsoaur’.
For all the latest info from the world of Kirby visit the Kirby Weblog.
Born This Day: Elkanah Billings
May 5, 1820 - June 14, 1896
From Today In Science History:
Billings was a Canadian geologist and paleontologist, who was the first Canadian paleontologist.
He published his first scientific paper on Trenton fossils in 1854. He launched a new monthly periodical, The Canadian Naturalist and Geologist in 1856, which he also edited and was the major contributor.
In Aug 1856 he was appointed staff paleontologist with the Canadian Geological Survey by William Edmond Logan, the founder of the Survey. Billings immediately began the task of identifying a 20-year backlog of fossils collected by the Survey. By 1863 he had published descriptions of no fewer than 526 new species of fossils.
The Billings medal, named in his honour, is awarded annually by the
Paleontology Division of the Geological Association of Canada as a means of recognizing the most outstanding of its paleontologists.
Click HERE for more information on the Geological Association of Canada.
Portrait of Elkanah Billings GSC photo 69323 (c)
From Today In Science History:
Billings was a Canadian geologist and paleontologist, who was the first Canadian paleontologist.
He published his first scientific paper on Trenton fossils in 1854. He launched a new monthly periodical, The Canadian Naturalist and Geologist in 1856, which he also edited and was the major contributor.In Aug 1856 he was appointed staff paleontologist with the Canadian Geological Survey by William Edmond Logan, the founder of the Survey. Billings immediately began the task of identifying a 20-year backlog of fossils collected by the Survey. By 1863 he had published descriptions of no fewer than 526 new species of fossils.
The Billings medal, named in his honour, is awarded annually by the
Paleontology Division of the Geological Association of Canada as a means of recognizing the most outstanding of its paleontologists.
On April 27, 1869, the Director of the GSC, Sir William Logan wrote this curt note to the paleontologist Elkanah Billings: "Your constant absence from the office is a worrying annoyance, particularly as I have reason to suspect that it does not arrive from rheumatism".For more info on Billings click HERE.
Click HERE for more information on the Geological Association of Canada.
Portrait of Elkanah Billings GSC photo 69323 (c)
Friday, May 04, 2007
Loch Ness Toad
MIT researchers carrying out a sonar survey of Loch Ness have been amazed to find a common toad crawling in the mud 98m down.From BBC news:
The institute said
the scan was part of its continuing efforts to find animal remains preserved at the low temperatures at the loch bottom that might explain unusual sightings on the surface. MIT said it had completed a side-scan sonar map of the entire length of the loch - which is about 750ft (228m) at its deepest point. The data has been compared with a geological map of the bottom made by Sir Edward Murray using plumb lines 100 years ago.
Born This Day: Thomas Huxley
May, 4, 1825 -- June 29, 1895.
From the UC Berkeley Page:
Huxley 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.
From the UC Berkeley Page:
Huxley 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.
Thursday, May 03, 2007
Why TV Is Bad For You
Art © Tom Bagley
From his sketchbook it seems like Tom's been looking at some great old Charles Knight art!
Australia Unveils New Titanosaurs
Image from the Queensland Museum
Unveiled today at the Queensland Museum, the largest dinosaur bones found in Australia came from the remains of two titanosaurs uncovered in the Winton Formation (100 million years ago), west of Charleville, in 2005 and 2006.
"We don't have a scientific name for this type of titanosaur because we believe they are a new type of species," Queensland Museum curator of geosciences, Scott Hocknull, said.
"These are the largest bones ever discovered in Australia. They would have been about two buses in length." The largest of the bones measures 1.5 metres long and weighs 100kg.
Wednesday, May 02, 2007
Born This Day: Sir D'Arcy Thompson
May 2, 1860 – June 21, 1948
From cscs.umich.edu:
D'Arcy Thompson was a British biologist whose masterwork, On Growth and Form, is a profound consideration of the shapes of living things, starting from the simple premise that "everything is the way it is because it got that way." Hence one must study not only
finished forms, but also the forces that moulded them: "the form of an object is a 'diagram of forces', in this sense, at least, that from it we can judge of or deduce the forces that are acting or have acted upon it."
Now by "forces" Thompson meant forces, and one of his great themes is the tremendous light cast on living things by using mathematics to describe their shapes and fairly simple physics and chemistry to explain them. In other words, Thompson wrote a thousand page treatise on self-organization long before the word existed.
one another. The most thoroughly worked out modern example of this is Raup's analysis of snail shell shapes with a morphospace.
With some simplification, the axes on the fish grids in here or the snails of the morphospace can be thought of as growth gradients. The evolutionary change between the species would then have been produced by a genetic change in the regulatory mechanisms controlling those gradients.
If we looked at these fish without the grids we might think that an evolutionary change from one into the other would be at least moderately complicated. The interest of D'Arcy Thompson's diagrams is then to show that shape changes could have been produced by heterochrony - a change in the rate or timing of development of some cell lines in the body relative to others.
Figure: a D'Arcy Thompson transformational diagram. The shapes of two species of fish have been plotted on Cartesian grids. Image from HERE.
From cscs.umich.edu:
D'Arcy Thompson was a British biologist whose masterwork, On Growth and Form, is a profound consideration of the shapes of living things, starting from the simple premise that "everything is the way it is because it got that way." Hence one must study not only
finished forms, but also the forces that moulded them: "the form of an object is a 'diagram of forces', in this sense, at least, that from it we can judge of or deduce the forces that are acting or have acted upon it."Now by "forces" Thompson meant forces, and one of his great themes is the tremendous light cast on living things by using mathematics to describe their shapes and fairly simple physics and chemistry to explain them. In other words, Thompson wrote a thousand page treatise on self-organization long before the word existed.
From Blackwell Publishing:D'Arcy Thompson found that related species superficially looking very different could in some cases be represented as simple Cartesian transformations of
one another. The most thoroughly worked out modern example of this is Raup's analysis of snail shell shapes with a morphospace.With some simplification, the axes on the fish grids in here or the snails of the morphospace can be thought of as growth gradients. The evolutionary change between the species would then have been produced by a genetic change in the regulatory mechanisms controlling those gradients.
If we looked at these fish without the grids we might think that an evolutionary change from one into the other would be at least moderately complicated. The interest of D'Arcy Thompson's diagrams is then to show that shape changes could have been produced by heterochrony - a change in the rate or timing of development of some cell lines in the body relative to others.
Figure: a D'Arcy Thompson transformational diagram. The shapes of two species of fish have been plotted on Cartesian grids. Image from HERE.
Tuesday, May 01, 2007
Looking At Dino Footprints
Preservation and Erosion of Theropod Tracks in Eolian Deposits: Examples from the Middle Jurassic Entrada Sandstone, Utah, U.S.A.. 2007. J. Milàn and D. B. Loope. J. Geology 115: 375-386.
From the press release:
The authors studied a range of larger tracks from the family of dinosaurs that includes the T. Rex and the tridactyl, and provide a guide for interpreting the effects of many different types of erosion on these invaluable impressions.
“Well-preserved vertebrate tracks in the rock record can be an invaluable source of information about foot morphology, soft tissue distribution, and skin texture,” said Milàn. “However, in most instances, the tracks are less than perfectly preserved, and sometimes they can be barely recognizable as tracks at all.”
With this in mind, Milàn and Loope sought to describe and categorize different levels of preservation. For example, dinosaur tracks may still exist as true tracks, that is, the original prints left in the ground by the dinosaur. True tracks preserve many of the anatomical details of the foot, such as number of digits and impressions of claws.
However, the true tracks may be filled with sediment or the original tracked surface may have eroded away. In the latter case, erosion may expose prominent layers of concentric circles extending from the former location of the true track. These “undertracks” reveal the squishing and displacement of sand when the heavy dinosaur took a step.
From the press release:
The authors studied a range of larger tracks from the family of dinosaurs that includes the T. Rex and the tridactyl, and provide a guide for interpreting the effects of many different types of erosion on these invaluable impressions.
“Well-preserved vertebrate tracks in the rock record can be an invaluable source of information about foot morphology, soft tissue distribution, and skin texture,” said Milàn. “However, in most instances, the tracks are less than perfectly preserved, and sometimes they can be barely recognizable as tracks at all.”
With this in mind, Milàn and Loope sought to describe and categorize different levels of preservation. For example, dinosaur tracks may still exist as true tracks, that is, the original prints left in the ground by the dinosaur. True tracks preserve many of the anatomical details of the foot, such as number of digits and impressions of claws.
However, the true tracks may be filled with sediment or the original tracked surface may have eroded away. In the latter case, erosion may expose prominent layers of concentric circles extending from the former location of the true track. These “undertracks” reveal the squishing and displacement of sand when the heavy dinosaur took a step.
Born This Day: Pierre Teilhard de Chardin
May 1, 1881 – April 10, 1955
From the San Jose University webpage:
Teilhard de Chardin was a paleontologist, Jesuit priest and philosopher, who was born in Auvergne, France. He lectured in science at the Jesuit College in Cairo, became professor of geology at the Intitut Catholique in Paris, and studied at the Institute of Human Paleontology
at the Museum of Natural History in Paris. In 1922 he obtained his doctorate and a year later left France on a paleontological expedition to China, where he stayed until 1946.
His many writings include Building the Earth, Le Milieu Divin, Trialogues at the Edge of the West, various essays. His major work, The Phenomenon of Man (written 1938-40) was posthumously published. Based on Teilhardís scientific thinking, it argues the humanity is in a continuous process of evolution towards a perfect spiritual state.
From the San Jose University webpage:
Teilhard de Chardin was a paleontologist, Jesuit priest and philosopher, who was born in Auvergne, France. He lectured in science at the Jesuit College in Cairo, became professor of geology at the Intitut Catholique in Paris, and studied at the Institute of Human Paleontology
at the Museum of Natural History in Paris. In 1922 he obtained his doctorate and a year later left France on a paleontological expedition to China, where he stayed until 1946. His many writings include Building the Earth, Le Milieu Divin, Trialogues at the Edge of the West, various essays. His major work, The Phenomenon of Man (written 1938-40) was posthumously published. Based on Teilhardís scientific thinking, it argues the humanity is in a continuous process of evolution towards a perfect spiritual state.