Humans Killed Australian Megafauna

And Then There Were None?. 2010. R. G. Roberts & B. W. Brook. Science 327: 420-422.

New research indicates that humans, not climate change, caused the demise of Australia's megafauna - giant marsupials, huge reptiles and flightless birds - at least 40,000 years ago.

2001: A Space Odyssey © MGM. Art & Story by Jack Kirby © Marvel Comics

Improved dating methods show that humans and megafauna only co-existed for a relatively short time after people inhabited Australia, adding weight to the argument that hunting led to the extinction of large-bodied species.

One site in western NSW - Cuddie Springs - stood out as an anomaly. Fossils of super-sized kangaroos, giant birds and the rhino-sized Diprotodon (the largest marsupial ever to roam Australia) were found in the same sedimentary layers as stone tools, leading some scientists to previously claim "unequivocal evidence" of a long overlap of humans and megafauna.

New methods to directly date bones and teeth of extinct species show that megafauna fossils and Aboriginal tools do not all date from the same period- they were mixed together over many thousands of years, long after the giant animals had died.

"Given that people arrived in Australia between 60,000 and 45,000 years ago, human impact was the likely extinction driver, either through hunting or habitat disturbance," he says. link

Dinosaur Death Pits

Dinosaur Death Pits from the Jurassic of China. 2010. D.A. Eberth, et al. Palaios 25: 112-125.


Two small Guanlong wucaii dinosaurs struggle to escape a muddy pit in what is now China during the late Jurassic period. Painting by Michael Skerpnick

ABSTRACT [edit]: Three newly discovered bonebeds from the Shishugou Formation of Xinjiang, China, are unusual in preserving vertically stacked and articulated to associated skeletons of at least 18 small, non-avian theropod dinosaurs in pits that are 1–2m deep.

There is no evidence that the pits were discrete depressions in the topography that filled through time. Rather, they appear to have been highly localized areas of liquefaction caused by large-dinosaur (possibly sauropod) trampling of saturated sediments.

Evidence indicates that the small theropods, and some other small vertebrates, became mired and died in these mud-filled pits. High quality skeletal preservation suggests that most individuals were buried within days to months after their deaths. Carcasses were buried successively, coming to rest above previously buried individuals.

Given the large sizes of the pits relative to the small body sizes of the vertebrates contained within them, we conclude that small vertebrates (3m long and 1 m tall) were particularly susceptible to miring at these sites.

Although the small, presumably herbivorous ceratosaur, Limusaurus inextricabilis, dominates the combined small theropod assemblage from these bonebeds, there is no evidence that any biological features other than its small size and a large, and possibly, gregarious local population were responsible for its becoming mired in large numbers.

A bias for small theropods in these bonebeds, compared to their relatively low abundance in the overall Shishugou Formation fauna, underscores that small theropods are underrepresented in Mesozoic fossil assemblages collected from other ancient alluvial and paludal settings.

Read the story at National Geographic News

New Model For The Origin of Primates

Evolution and biogeography of primates: a new model based on molecular phylogenetics, vicariance and plate tectonics. 2009. Zoologica Scripta, Published Online: 10 Nov 2009



A new model for primate origins argues that the distributions of the major primate groups are correlated with Mesozoic tectonic features and that their respective ranges are congruent with each evolving locally from a widespread ancestor on the supercontinent of Pangea about 185 million years ago.



"According to prevailing theories, primates are supposed to have originated in a geographically small area (center of origin) from where they dispersed to other regions and continents" said Heads, who also noted that widespread misrepresentation of fossil molecular clocks estimates as maximum or actual dates of origin has led to a popular theory that primates somehow crossed the globe and even rafted across oceans to reach America and Madagascar.

In this new approach to molecular phylogenetics, vicariance, and plate tectonics, Heads shows that the distribution ranges of primates and their nearest relatives, the tree shrews and the flying lemurs, conforms to a pattern that would be expected from their having evolved from a widespread ancestor. This ancestor could have evolved into the extinct Plesiadapiformes in north America and Eurasia, the primates in central-South America, Africa, India and south East Asia, and the tree shrews and flying lemurs in South East Asia.

Detective Chimp (c) DC Comics

Divergence between strepsirrhines (lemurs and lorises) and haplorhines (tarsiers and anthropoids) is correlated with intense volcanic activity on the Lebombo Monocline in Africa about 180 million years ago. The lemurs of Madagascar diverged from their African relatives with the opening of the Mozambique Channel (160 million years ago), while New and Old World monkeys diverged with the opening of the Atlantic about 120 million years ago.

Biogeographic evidence for the Jurassic origin for primates, and the pre-Cretaceous origin of major primate groups considerably extends their divergence before the fossil record, but Heads notes that fossils only provide minimal dates for the existence of particular groups, and there are many examples of the fossil record being extended for tens of millions of years through new fossil discoveries. link

Died This Day: Frank Reicher

Frank Reicher (Dec. 2, 1875 - Jan. 19, 1965) was a German actor, director and producer born in Munich, Germany. During the early part of the twentieth century he was often on Broadway, occasionally in leading roles, but he is most familiar to modern audiences as a supporting character actor in films.

He is probably best known for playing Captain Englehorn in the movies King Kong and Son of Kong in 1933. link

MLK DAY at CMNH

In celebration of Martin Luther King Day yesterday, the Cleveland Museum of Natural History had free admission for the public. More than 5000 visitors came by to talk with the curators, staff and volunteers who moved out of their offices and labs and into the galleries for the day. Here are just a few images from yesterday.


Vert Paleo volunteer George explains placoderm fish.


Vert Paleo volunteer Joe describes the Nanotyrannus that got away from him.


Junior docent in training, Ryan, explains all you need to know about small tyrannosaurs.


High School volunteers Henry and Matt compare modern shark jaws to Devonian fossil jaws.


Physical Anthropology


Archaeology


Anne Sanford from the Phys. Anthro Casting Lab demonstrates facial reconstructions.

So does Dr. Linda Spurlock, Director of Human Health


Dr. Joe Hannibal and CWRU Work Study Student, Jeff, talk about rocks & invertebrate fossils.

Thanks to everyone for making this year's MLK Day a great success!

Osteology of Falcarius utahensis

Osteology of Falcarius utahensis (Dinosauria: Theropoda): characterizing the anatomy of basal therizinosaurs. 2010. L. E. Zanno. Zool. J. Linn. Soc. :196-230.



ABSTRACT [edit]: Falcarius utahensis, from the lower Yellow Cat Member of the Cedar Mountain Formation, represents the most complete and morphologically primitive therizinosaur yet discovered. This work completes the description of skeletal material prepared from the Crystal Geyser Quarry subsequent to the first five years of excavation.

Results of this study reveal a significant degree of morphological disparity between Falcarius utahensis and the evidently coeval primitive therizinosaur Beipiaosaurus inexpectus from the Yixian Formation, People's Republic of China and help characterize morphological transformations occurring in the therizinosaur lineage.

Falcarius documents that marked heterodonty – characterized by elongate, incisiform rostral teeth – is present in basal therizinosaurs and oviraptorosaurs (i.e. Incisivosaurus gauthieri, Protarchaeopteryx robusta), and either represents a synapomorphy or symplesiomorphy for these groups or an early phase in the convergent progression toward rostral endentulism. Nonetheless, heterodonty suggests that diet was a primary factor in the early evolution of both clades.

Died This Day: George Ledyard Stebbins

From the U Calif., Berkeley:

Along with Dobzhansky (1900 - 1975), animal systematist Ernst Mayr, and paleontologist George Gaylord Simpson (1902 - 1984), Stebbins (Jan. 6, 1906 - Jan. 19 2000) is considered one of the "architects" of the modern evolutionary synthesis of the 1930s and 1940s, an intellectual watershed and historic turning point that brought together research in cytology, genetics, systematics, paleontology into a common evolutionary framework.

This synthesis, which had the effect of reconciling the often opposing views of laboratory-oriented geneticists and natural history oriented systematists, made Charles Darwin's theory of evolution by natural selection the centerpiece of the new discipline of evolutionary biology.

In this role, Stebbins is credited with bringing a modern framework to the study of plant evolution, and he is perhaps best known for his book Variation and Evolution in Plants, published by Columbia University Press (NY) in 1950. In the 1940s, Stebbins also played an important role in organizing the nascent Society for the Study of Evolution, of which he became the third president in 1948, and used his position to speak out for the botanical side of evolutionary studies, a field that had been dominated by zoologists. Photo .

Developmental Palaeontology

Developmental palaeontology in synapsids: the fossil record of ontogeny in mammals and their closest relatives. 2010. M. R. Sánchez-Villagra. Proc. Roy. Soc. B. Published online before print January 13.

Abstract: The study of fossilized ontogenies in mammals is mostly restricted to postnatal and late stages of growth, but nevertheless can deliver great insights into life history and evolutionary mechanisms affecting all aspects of development.

Fossils provide evidence of developmental plasticity determined by ecological factors, as when allometric relations are modified in species which invaded a new space with a very different selection regime. This is the case of dwarfing and gigantism evolution in islands.

Skeletochronological studies are restricted to the examination of growth marks mostly in the cement and dentine of teeth and can provide absolute age estimates. These, together with dental replacement data considered in a phylogenetic context, provide life-history information such as maturation time and longevity.

Palaeohistology and dental replacement data document the more or less gradual but also convergent evolution of mammalian growth features during early synapsid evolution. Adult phenotypes of extinct mammals can inform developmental processes by showing a combination of features or levels of integration unrecorded in living species. Some adult features such as vertebral number, easily recorded in fossils, provide indirect information about somitogenesis and hox-gene expression boundaries.

Developmental palaeontology is relevant for the discourse of ecological developmental biology, an area of research where features of growth and variation are fundamental and accessible among fossil mammals.

Download the PDF HERE.

Born This Day: August Weismann

From Today In Science History:

August (Friedrich Leopold) Weismann (Jan. 17, 1834 – Nov. 5, 1914) was a German biologist and one of the founders of the science of genetics. He is best known for his opposition to the doctrine of the inheritance of acquired traits and for his "germ plasm" theory, the forerunner of DNA theory.

Weismann conceived the idea, arising out of his early observations on the Hydrozoa, that the germ cells of animals contain "something essential for the species, something which must be carefully preserved and passed on from one generation to another."

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

More info from Science World. image

Born This Day: Gaspard Bauhin

From Today In Science History:

Bauhin (Jan. 17, 1560 - Dec. 5, 1624) was a Swiss physician, anatomist, and botanist who introduced a scientific binomial system of classification to both anatomy and botany. In 1623 Bauhin produced the Pinax Theatri Botanici, the first attempt to summarize a confusing array of names. It was a monumental compilation that pulled together uncoordinated plant names and descriptions of 6000 species that had appeared in Theophrastus and Dioscorides, as well as in later herbals and other plant records.

By accepting Bauhin's compilation, Linnaeus was able to avoid many of the complications of the ancient literature.

Born This Day: Caroline Munro

Art © Mark Schultz

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

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

Born This Day: Ruth Rose

Ruth Rose (Jan. 16, 1896 - June 8, 1978) was the daughter of Edward E. Rose. In 1926 she meet (and later married) cinematographer Ernest Schoedsack when they were both working on a New York Geological Society expedition to the Galapagos Islands. Together with partner and fellow producer director, Meriam C. Cooper, and animator Willis O’Brien, they made “King Kong”, released in 1933.

Rose shared in many of Schoedsack’s and Cooper’s wilderness film productions, and worked as a writer or script doctor on King Kong, Son of Kong, She, The Last Days of Pompeii and Mighty Joe Young.

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

Unidirectional Airflow in the Lungs of Alligators. 2010. C. G. Farmer and K. Sanders. Science 327: 338-340.

Air flows in one direction as it loops through the lungs of alligators, just as it does in birds. The study suggests this breathing method may have helped the dinosaurs' ancestors dominate Earth after the planet's worst mass extinction 251 million years ago.

Such a breathing pattern likely evolved before 246 million years ago, when crocodilians split from the branch of the archosaur family tree that led to pterosaurs, dinosaurs and birds.

Image: C.G. Farmer & Kent Sanders, U. of Utah

Computerized tomographic (CT) X-ray images of side and top views of a 24-pound American alligator, with 3-D renderings of the bones and of airways or bronchi within the lungs. The windpipe and first-tier of bronchi are not shown. Air flows in one direction through a gator's lungs. It flows from the first-tier bronchi through second-tier bronchi (blue), then through tube-like third-tier parabronchi (not shown) and then back through other second-tier bronchi (forest green).

This means that one-way airflow evolved in archosaurs earlier than once thought, and may explain why those animals came to dominance in the Early Triassic Period, after the extinction and when the recovering ecosystem was warm and dry, with oxygen levels perhaps as low as 12 percent of the air compared with 21 percent today.

Farmer emphasized the discovery does not explain why dinosaurs, which first arose roughly 230 million years ago, eventually outcompeted other archosaurs.

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

d'Halloy (Feb. 16, 1783 - Jan. 15, 1875) was a Belgian geologist who was an early proponent of evolution and was acknowledged by Charles Darwin in his preface to ‘On The Origin of the Species’ for his opinions on the origin of new species through descent with modification.

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

Died This Day: Alpheus Hyatt

From Today in Science History:

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

Along with E. Cope, Hyatt (April 5, 1838 - Jan. 15, 1902) was the most prominent American neo-Lamarckian. Based on the analogy of ontogeny with phylogeny, Hyatt claimed that lineages, like individuals, had cycles of youth, old age, and death (extinction). This idea became the bulwark of orthogenetic theories in the U.S. Hyatt was the founder and first editor of the American Naturalist, and first president of Woods Hole laboratory.

Opened To The Public (1759): The British Museum

image.

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

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

Born This Day: Father of Paleobotany

Adolphe-Théodore Brongniart (Jan. 14, 1801 - Feb. 18, 1876) was a French botanist whose classification of fossil plants drew surprisingly accurate relations between extinct and existing forms prior to Charles Darwin's principles of organic evolution. His work earned him the distinction as the founder of modern paleobotany.

He was an early proponent of evolutionary theory. Brongniart published the first complete account of fossil plants (1828). His interpretations of the fossil record also contributed to our understanding of historical changes in climates and plant geography. link image

Born This Day: Nicolaus Steno

Steno (Jan. 10 – Nov. 26, 1686) was a Danish geologist and anatomist who first made unprecedented discoveries in anatomy, then established some of the most important principles of modern geology. He was Danish royal anatomist for 2 years.

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

Died This Day: Carolus Linnaeus

From the Linnean Society:

Linnaeus (May 23, 1707 – Jan. 10, 1778) 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.

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

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

Born This Day: Amadeus William Grabau

From Today In Science History:

Grabau (Jan 9, 1870 – March 20, 1946) was an American geologist and paleontologist, known for his work on world stratigraphic deposits and the deciphering of Earth history. In 1899, he published an early paper that studied the environment of old sedimentary rocks in light of knowledge of the conditions of life among modern organisms, The Relations of Marine Bionomy to Stratigraph, which was a step toward the development of paleoecology.

For more than a quarter of a century, he worked on the geologic survey of China. In 1940, he developed a theory of rhythms in the growth of the Earth's crust, and of repetitions in mountain building. image