Mammals Got Bigger After Dino Extinction

The Evolution of Maximum Body Size of Terrestrial Mammals. 2010. F.A. Smith, et al. Science 330: 1216-1219.

Tales to Astonish © Marvel Comics

Researchers have demonstrated that the extinction of dinosaurs 65 million years ago made way for mammals to get bigger - about a thousand times bigger than they had been. The study is the first to show this new pattern of increased body size of mammals after the exit of the dinosaurs. Mammals grew from a maximum of about 10 kg when they were sharing the earth with dinosaurs to a maximum of 17 tonnes afterwards.

"Basically, the dinosaurs disappear and all of a sudden there is nobody else eating the vegetation. That's an open food source and mammals start going for it, and it's more efficient to be an herbivore when you're big," says paper co-author Dr. Jessica Theodor.

Theodor says as well as confirming the dramatic growth in mammalian size after the dinosaurs, the study shows that the ecosystem is able to reset itself relatively quickly.

"You lose dinosaurs 65 million years ago, and within 25 million years the system is reset to a new maximum for the animals that are there in terms of body size. That's actually a pretty short time frame, geologically speaking," she says. "That's really rapid evolution."

"Nobody has ever demonstrated that this pattern is really there. People have talked about it but nobody has ever gone back and done the math," says Theodor one of the 20 researchers from around the world who worked on the study. link

Alison Boyer/Yale University

The largest land mammals that ever lived, Indricotherium and Deinotherium, would have towered over the living African elephant. The tallest on diagram, Indricotherium, an extinct rhino relative, lived during the Eocene to the Oligocene Epoch (37 to 23 million years ago) and reached a mass of 15,000 kg, while Deinotherium (an extinct proboscidean, related to modern elephants) was around from the late-Miocene until the early Pleistocene (8.5 to 2.7 million years ago) and weighed as much as 17,000 kg.

Born This Day: Karl Ernst Von Baer

Von Baer (Feb 29, 1792 - Nov 28, 1876) was a Prussian-Estonian embryologist who discovered the mammalian egg (1827) and the notochord. He established the new science of comparative embryology alongside comparative anatomy with the publication of two landmark volumes (in 1828 and 1837) covering the range of existing knowledge of the prebirth developments of vertebrates.

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

From Today In Science History

Died This Day: Richard Carlson

Carlson (April 29, 1912 – Nov. 24, 1977) starred as Dr. David Reid in the classic Creature From The Black Lagoon (1957). You know that he was the “good” scientist ‘cuz he got the girl, even though he let a cover story for Nature skulk back into the Lagoon.

Published This Day: The Origin of The Species

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From Today In Science History:

In 1859, The Origin of Species by Means of Natural Selection was published in England to great acclaim. In this groundbreaking book by British naturalist Charles Darwin, he argued that species are the result of a gradual biological evolution in which nature encourages, through natural selection, the propagation of those species best suited to their environments. This book is unquestionably one of the most influential in the history of science.

Iguanacolossus & Hippodraco: Two New Iguanodonts

New Basal Iguanodonts from the Cedar Mountain Formation of Utah and the Evolution of Thumb-Spiked Dinosaurs. 2010. A. MacDonald, et al. PLoS ONE 5(11): e14075.

The Early Cretaceous of Utah has two new species of iguanodonts that are beaked herbivorous dinosaurs.

Iguanodonts are found all over the world in rocks dating to the Early Cretaceous Epoch (~145.5-99.6 million years ago). Their fossils are particularly abundant and diverse in Europe and east-central Asia with Europes Iguanodon being only the second formally named dinosaur in 1825.

Hippodraco scutodens (“horse-dragon, shield tooth”) (above) was found at a site north of Arches National Park. It lived approximately 124 million years ago, at the same time as the predator Utahraptor.

Iguanacolossus fortis (“mighty colossal Iguana”) (above) was found at a site near the town of Green River. It is ~30ft long and is probably a few million years older than Hippodraco.

Click to enlarge

Reduced consensus tree of 11,850 MPTs of 358 steps each, following ordering of 22 multistate characters. Numbers below and to the left of some nodes correspond to the following clade names: 1, Ornithopoda; 2, Iguanodontia; 3, Rhabdodontidae; 4, Dryomorpha; 5, Dryosauridae; 6, Ankylopollexia; 7, Styracosterna; 8, Hadrosauriformes; 9, Hadrosauroidea.

Born This Day: Robert Armstrong

Armstrong (Nov. 20, 1890 – April 20, 1973) took Fay Wray to Skull Island in 1933. He returned later the same year to find The Son of Kong, only to lose him as the island sank, as these things are prone to doing.

Komodo Dragon Missing Link

Oldest known Varanus (Squamata: Varanidae) from the Upper Eocene and Lower Oligocene of Egypt: support for an African origin of the genus. 2010. R. B. Holmes Palaeontology 53: 1099–1110

Scientists say the unique shape of the vertebrae of the 33-million-year-old African lizard fossil links it with its cousin the Komodo, which has only been around for some 700,000 years.

"The African fossil was found on the surface of a windswept desert," said Holmes. "It's definitely from the lizard genus Varanus and there are more than 50 species alive today, including Komodos and other large lizards."

Holmes says the telltale African vertebrae fossils belonged to a lizard that was about a metre- and-a-half long whose ability to swim may be key to figuring out how more than 30 million years later its ancestors turned up on the other side of the world.

Holmes says the ancient African Varanus specimen was found on land that was once the bottom of a river or small lake. "Whether the animals lived in the water or surrounding land, we don't know, but we do know that some modern day species of Varanus are comfortable swimming in fresh water."

The work runs counter to some prevailing theories about the origins of some ancient fossil types found in Africa including Varanus lizards and some fresh-water fish. "The assumption for several types of ancient African fossils is that the animals didn't originate in Africa but came there from Asia," says Holmes. "But the fossil record of Varanus shows exactly the opposite path of migration." link

Died This Day: John William Dawson

Dawson (Oct. 30, 1820 - Nov. 20, 1899>) was a Canadian geologist who made numerous contributions to paleobotany and extended the knowledge of Canadian geology. Dawson was born and raised in Pictou, Nova Scotia, where the many sandstone and coal formations provided fertile ground for his first scientific explorations, which culminated in the publication of Acadian Geology. He made many important discoveries of fossil life, great and small. These included fossil plants, trackways of lowly invertebrates, footprints, skeletons of reptiles and amphibians, millipedes and the earliest land snails. When the famous geologist Charles Lyell visited coal deposits in Pictou, Dawson acted as his guide.

In 1851, Dawson and Lyell teamed up again to examine the interiors of fossil tree trunks at Joggins, Nova Scotia. They discovered the remains of some of the earliest known reptiles, Hylonomus lyelli, along with other rare fossils, propelling this part of the world into the international spotlight.

Dawson became principal of McGill College in Montreal in 1854, which he made into a reputable institution. He remained there, teaching geology and palaeontology and acting as librarian, until his retirement. One of his lifelong dreams was realized in 1882 when Peter Redpath gave money to McGill for the construction and establishment of a museum, naming Dawson as director. Today the Peter Redpath Museum of Natural History houses many specimens from Dawson's personal collection.

Info from HERE and HERE. Images from HERE and HERE.

Born This Day: Noble Johnson

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“Meanwhile, the light-skinned Noble Johnson (April 18, 1881 – Jan. 9, 1978) was heavily made up for his role as the village chief [in 1933's, KING KONG]—he was a leading black actor of the era (known as “America’s premiere Afro-American screen star” in the black press) and therefore worth the extra consideration. Johnson, an ex-cowboy, horse trainer, and boxer, had quite a resume before portraying the Chief of Skull Island.

He was a student of all aspects of movie making from directing to distribution, and instrumental in the 1916 formation of the Lincoln Motion Picture Company, created to produce what were called “race movies.” Johnson left the company after it had released three films, rumored to have been “encouraged” by Universal to do so or lose any opportunity for parts at the bigger studio.

Johnson - a childhood friend of Lon Chaney - portrayed a variety of ethnicities in his long career; one of the few black actors of Hollywood’s early era to be allowed any diversity in roles.” From Kong Is King.net

This Just In: Pterosaurs Can Fly!

On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness. 2010. M.P. Witton & M.B. Habib.PLoS ONE 5(11): e13982.

Grrr! Kong hate stupid press release catch phrases!

Controversial claims that enormous prehistoric winged beasts could not fly have been refuted by the most comprehensive study to date which asserts that giant pterosaurs were skilled in flight.

New research indicates that the giant pterosaurs took off by using all four of their limbs and effectively ‘pole-vaulting’ over their wings using their leg muscles and pushing from the ground using their powerful arm muscles. Once airborne they could fly huge distances and even cross continents.

These creatures were not birds; they were flying reptiles with a distinctly different skeletal structure, wing proportions and muscle mass. They would have achieved flight in a completely different way to birds and would have had a lower angle of take off and initial flight trajectory. The anatomy of these creatures is unique.”

Drs Witton and Habib suggest that, with up to 50 kg of forelimb muscle, the creatures could easily have launched themselves into the air despite their massive size and weight.

They concluded that not only could pterosaurs fly, they could do so extremely well and could have traveled huge distances and even crossed continents. It’s unlikely that they would need to flap continuously to remain aloft but would flap powerfully in short bursts with their large size allowing them to achieve rapid cruising speeds. link

Vist Pterosaur-Net Blog, a blog in the spirit of the palaeoblog, but all about pterosaurs. Thanks for the Kong image guys!

Too bad the "junk in the trunk" entry slips off the front page. Victoria, shouldn't that be immortalized in a new Currie Lab t-shirt?

Debuted This Day: The Ghost of Slumber Mountain

The Ghost of Slumber Mountain was written and directed by special effects pioneer Willis O'Brien and produced by Herbert M. Dawley. When O’Brien went on to greater fame with The Lost World Dawley sued the film makers for patent infrigment, claiming that he, not O’Brien, had invented stop-motion animation. Although this was not the case, filming saw head up while the case was sorted out.

Both O’Brien and Hawley star as the ghost of Mad Dick and Uncle Jack Holmes, respectively.

Born This Day: Julie Adams

Julie starred as Kay Lawrence in The Creature From The Black Lagoon (1954). Adams has had a long career in films and TV, recently appearing on 'Lost'.

The Junk In The Trunk of T. rex

The Tail of Tyrannosaurus: Reassessing the Size and Locomotive Importance of the M. caudofemoralis in Non-Avian Theropods. 2010. W. S. Persons and P.J. Currie. The Anatomical Record, published online: Nov. 12.

Devil Dinosaur © Marvel Comics

T. rex's rear end has been given a makeover by University of Alberta graduate student Scott Persons. His extensive research shows that powerful tail muscles made the giant carnivore one of the fastest moving hunters of its time.

As Persons says, "contrary to earlier theories, T. rex had more than just junk in its trunk."



The tails of both T.rex and modern animals are given their shape and strength by rib bones attached to the vertebrae. Persons found that the ribs in the tail of T. rex are located much higher on the tail. That leaves much more room along the lower end of the tail for the caudofemoralis muscles to bulk-up and expand. Without rib bones to limit the size of the caudofemoralis muscles, they became a robust power-plant enabling T.rex to run.

Persons extensive measurements of T.rex bones and computer modeling shows previous estimates of the muscle mass in the dinosaur's tall were underestimated by as much as 45 per cent.

That led many earlier T. rex researchers to believe the animal lacked the necessary muscle mass for running which in turn limited its hunting skills. That lack of speed cast T. rex in the role of a scavenger only able to survive by feeding on animals killed by other predators.

As for an T. rex's exact speed, researchers say that is hard to measure, but Persons says it could likely run down any other animal in its ecosystem. link

Died This Day: Carl Akeley

Read his story over at Atomic Surgery

The Hall of African Mammals at the American Museum of Natural History exists thanks to the efforts of Carl Akeley (May 19, 1864 - Nov 17, 1926) who was the kind of adventurer that Indy Jones could only dream of being.



He died on an African expedition in 1926, ten years before this hall was completed and was buried in a place depicted in the Hall's famous Gorilla Diorama. Of course we approach collecting and conservation differently today, but Akeley is to be commended for his love of nature and his desire to present its hidden corners to the world.

From Today In Science History:

Carl Ethan Akeley was an American naturalist and explorer who developed the taxidermic method for mounting museum displays to show animals in their natural surroundings. His method of applying skin on a finely molded replica of the body of the animal gave results of unprecedented realism and elevated taxidermy from a craft to an art. He mounted the skeleton of the famous African elephant Jumbo. He invented the Akeley cement gun to use while mounting animals, and the Akeley camera which was used to capture the first movies of gorillas.

Massospondylus Embryos

The Massospondylus embryos are in the news again thanks to a recent article in JVP.

I blogged about the 2005 Science paper here. Read the new story at National Geographic News

The 1st C4 Grass

Isotopic evidence of C4 grasses in southwestern Europe during the Early Oligocene–Middle Miocene. 2010. M.A. Urban, et al. Geology, First published online November 12.

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A new analysis of fossilized grass-pollen grains deposited on ancient European lake and sea bottoms 16-35 million years ago reveals that C4 grasses evolved during the early part of the Oligocene, some 14 million years earlier than previously thought. This new evidence casts doubt on the widely-held belief that the rise of this incredibly productive group of plants was driven by a large drop in atmospheric carbon dioxide concentrations during the Oligocene epoch.

C4 plants compose only 3 percent of flowering plant species, yet account for about 25 percent global terrestrial productivity. About 60% of C4 species are grasses, and they dominate the world's grassland and savanna biomes, particularly those in warmer, lower latitude areas. Their ecological success results from the way these species concentrate and then fix carbon dioxide in order to power photosynthesis. link

Born This Day: Sir Charles Lyell

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

Sir Charles Lyell (Nov. 14, 1797 - Feb. 22, 1875) attended Oxford University at age 19. Lyell's father was an active naturalist. Lyell had access to an elaborate library including subjects such as Geology.

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

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

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

Image from King’s College London.

Fantasia Debuts (1940)

Walt Disney’s epic film, Fantasia, opened this day on Broadway in New York City in 1940. The film featured Leopold Stokowski and the Philadelphia Orchestra performing a number of pieces of classical music to the film’s animated visuals. Igor Stravinsky’s “Rite of Spring” provided the score for the evolution of the Earth including a wonderful sequence on the extinction of the dinosaurs at the end of the Cretaceous. Many school teachers actually showed this sequence in science class -- that’s where I first saw it!

Born This Day: Helen Mack

Nov 13, 1913 – August 13, 1986

Helen starred as Helene Peterson in “Son of Kong”, the quickie follow up to “King Kong”. Once again Carl Denham leads a beautiful girl into danger on Skull Island.

Born This Day: Julie Ege

Nov. 12, 1943 – April 29, 2008

Julie had the lead role as Nala in the 1971 Hammer film, “Creatures The World Forgot”.

Died This Day: Gideon Mantell

Mantell (Feb. 3, 1790 – Nov. 10, 1852), a physician of Lewes in Sussex in southern England, had for years been collecting fossils in the sandstone of Tilgate forest, and he had discovered bones belonging to three extinct species: a giant crocodile, a plesiosaur, and Buckland's Megalosaurus. But in 1822 he found several teeth that "possessed characters so remarkable" that they had to have come from a fourth and distinct species of Saurian. After consulting numerous experts, Mantell finally recognized that the teeth bore an uncanny resemblance to the teeth of the living iguana, except that they were twenty times larger.
In this paper, the second published description of a dinosaur, he concluded that he had found the teeth of a giant lizard, which he named Iguanodon, or "Iguana-tooth."

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

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

Info and plate from HERE.

Born This Day: Francis Maitland Balfour

Balfour (Nov. 10, 1851 – July 19, 1882) was a British zoologist and a founder of modern embryology. Influenced by the work of Michael Foster, with whom he wrote Elements of Embryology (1883), Balfour showed the evolutionary connection between vertebrates and certain invertebrates (similar to research being done by Aleksandr Kovalevski).

Balfour proposed the term Chordata for all animals possessing a notochord at some stage in their development. He also did pioneer work on the development of the kidneys and related organs, as well as the spinal nervous system. While convalescing from typhoid fever in Switzerland, he died at the young age of 30 from a fall while attempting an ascent of the unconquered Aiguille Blanche of Mont Blanc. From Today In Science History

Died This Day: Alfred Russel Wallace

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

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

From Today In Science History

The Alfred Russel Wallace page HERE. More HERE.

Died This Day: Henry Fairfield Osborn

Osborn graduated (August 8, 1857 - November 6, 1935) from Princeton in 1877 and pursued his interest in the biological sciences and paleontology through additional study at several New York City medical schools and with Thomas Henry Huxley in Britain. Returning to the United States, Osborn accepted a position at Princeton, teaching natural sciences from 1881 until 1891, when he moved to Columbia University to organize the Biology Department there, and in 1891, he also helped to organize the Department of Vertebrate Paleontology at the American Museum of Natural History acting as it’s first curator. Osborn's close association with American Museum continued for over 45 years, and included a long tenure as its President, 1908-1933. During these years the museum's collections expanded enormously and it became one of the preeminent research institutions for natural history in the world.

Osborn is noted for describing and naming both Tyrannosaurus rex and Albertosaurus in 1905, Pentaceratops in 1923, and Velociraptor in 1924. One of Osborn's favorite groups for study was the brontotheres, and he was the first to carry out comprehensive research on them. He also wrote an influential textbook, The Age of Mammals (1910).

Apart from his own research, Osborn is perhaps best remembered for the sponsorship of the five immensely successful Central Asiatic Expeditions during the 1920's and 30's led by Roy Chapman Andrews.

Entry from HERE and HERE.

Died This Day: Alfred Sherwood Romer

”Romer (Dec. 28, 1894 – Nov. 5, 1973) was director of the Museum of Comparative Zoology at Harvard University until his retirement in 1961 and was one the singularly most influential vertebrate paleontologists of the 20th Century. His work ranged over virtually every conceivable subject within that field, although it was the osteology and taxonomy of the therapsids and other proto-mammals which was nearest his heart.

In addition to this work, Romer was acutely interested in the origin and initial adaptive radiation of tetrapods, and his work became the basis for a theory of tetrapod origins which was canon until the description of Acanthostega gunnari by Clack & Coates in the 1990s. Romer was ahead of his time in his defense of monophyly of Dinosauria though he did feel that Theropoda was not ancestral to birds.” link from EvoWiki.org

Romer’s book, Vertebrate Paleontology (1966), was for many years THE textbook on VP and is still well worth picking up. One of Romer’s students, Bob Carroll, wrote an updated version entitled, ‘Vertebrate Paleontology and Evolution’, in 1987. image

Born This Day: J.B.S. Haldane

Haldane (Nov. 5, 1892 - Dec. 1, 1964) is best remembered along with E. B. Ford and R. A. Fisher one of the three major figures to develop the mathematical theory of population genetics. His greatest contribution was in a series of ten papers on "A Mathematical Theory of Natural and Artificial Selection" which was the major series of papers on the mathematical theory of natural selection. It treated many major cases for the first time, showing the direction and rates of changes of gene frequencies. It also pioneered in investigating the interaction of natural selection with mutation and with migration.

Haldane's book, The Causes of Evolution (1932), summarized these results, especially in its extensive appendix. This body of work was a component of what came to be known as the "modern evolutionary synthesis", re-establishing natural selection as the premier mechanism of evolution by explaining it in terms of the mathematical consequences of Mendelian genetics. From Wikipedia. More info here.