Born This Day: Barnum Brown

Feb. 12, 1873 – Feb. 5, 1963

Photo © AMNH

From the AMNH bio:

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

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

Premiered This Day (1982): Quest For Fire

Directed by Jean-Jacques Annaud from the J.-H. Rosny novel

Go Read: The Secret Beneath The Earth!

Cave Carson’s 1st adventure.

Presented over at Atomic Surgery.

Extinct Ibex Cloned

First birth of an animal from an extinct subspecies (Capra pyrenaica pyrenaica) by cloning. 2009. J. Folch, et al. Theriogenology, published online 27 January 2009.

image

From National Geographic News:

The extinct Pyrenean ibex has been resurrected by cloning for the first time—though the clone died minutes after birth. Scientists used the frozen skin in 2003 to clone the bucardo, a subspecies of Spanish ibex that went extinct in 2000.

The Genetic Origin of the 1st Tooth

An ancient gene network is co-opted for teeth on old and new jaws. G.J. Fraser, et al. PLoS Biol 7(2): e1000031.

Schematic drawing (lateral view) of the generalized cichlid cranial skeleton, showing the relative location of the oral jaws (purple) and the pharyngeal jaws of PA7 (blue)

Scientists report that a common gene regulatory circuit controls the development of all dentitions, from the first teeth in the throats of jawless fishes that lived half a billion years ago, to the incisors and molars of modern vertebrates.

"It's likely that every tooth made throughout the evolution of vertebrates has used this core set of genes," said Gareth Fraser.

The first vertebrates to have teeth were a group of eel-like jawless fish known as the conodonts that had teeth not in their mouth, but lining the throat. This particular group is long since extinct, but some modern fish retain teeth in the throat (pharynx). Dr. Fraser and colleagues studied tooth formation in a group of fish known for their rapid rate of evolution, the cichlids of Africa's Lake Malawi. The cichlids have teeth both in their oral jaws, like humans, and deep in their throats on a pharyngeal jaw. A co-author of the paper, Darrin Hulsey, first identified a surprising positive correlation between the number of teeth in the oral jaw and in the throat in these fish.

The Coevolutionary History of Jaws and Dentitions. Full caption HERE
CLICK TO ENLARGE

"Originally, I thought there wouldn't be a correlation due to the developmental differences and the evolutionary distinction between the two jaw regions, but it turns out there is," explained Fraser. "So fish that have fewer oral teeth also have fewer pharyngeal teeth. This shows that on some level there's a genetic control that governs the number of teeth in both regions."

The team investigated what this control might be by using a technique localizing gene expression in the cells during tooth development, known as in situ hybridization, and found that a common genetic network governs teeth in the two locations. link

Published This Day: Steno's "Head of a Shark"

From Today In Science History:

In 1667, a classic paleontological paper by Nicolaus Steno was published by the Royal Society, London. His topic, Head of a shark dissected, represented the first such scientific paper to recognise that fossils were the remains of creatures who had died and subsequently had become petrified. Controversy resulted as the same claim had been made in the time of the ancient Greeks, two millennia earlier.

Belated Happy Birthday to this blog that turned 4 years old last Sunday, with more than 1800 postings since we started.

New Alaskan Ichthyosaur Unveiled

The University of Alaska Museum of the North has unveiled what officials call one of the largest, oldest and northernmost marine reptile fossils ever found.

Officials say the fossil sat in the Brooks Range for almost 210 million years before it was discovered in 1950, eventually arriving in Fairbanks.

Discovered by geologist Bud Ken and Carl Benson while mapping rocks in the foothills of the Brooks Range along Cutaway Creek, 200 miles south of Point Barrow, it waited another 50 years to be collected.

The fossil sat in museum storage for five years before it was rediscovered by our old friend, Dr. Patrick Druckenmiller (above), the Earth sciences curator for Museum of the North, who has been cleaning and studying the fossilized marine reptile over the past year. link.

Guardian Dinosaurs

The UK Newspaper, The Guardian, has a nice web site devoted to dinosaurs. Each single web page features a colour illustration and information about a specific dinosaur or answers a question about them. It’s a great resource for kids, and adults will learn a few new things as well.

Died This Day: Mendel's 1st Paper

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

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

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

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

Read the paper HERE.

Schinderhannes & the Origin of Claws

A Great-Appendage Arthropod with a Radial Mouth from the Lower Devonian Hunsrück Slate, Germany. 2009. G. Kühl , et al. Science 323: 771 – 773.

Schinderhannes/Elke Groening

A missing link in the evolution of the front claw of living scorpions and horseshoe crabs was identified with the discovery of a 390 million-year-old fossil, Schinderhannes bartelsi.

With a head like the giant Cambrian aquatic predator Anomalocaris and a body like a modern arthropod, the specimen (below) is the only known example of this unusual creature. The fossil's head section has large bulbous eyes, a circular mouth opening and a pair of segmented, opposable appendages with spines projecting inward along their length. The trunk section is made up of 12 segments, each with small appendages, and a long tail spine. Between the head and trunk, there is a pair of large triangular wing-like limbs — that likely propelled the creature like a swimming penguin. Unlike its ancestors from the Cambrian period, which reached three feet in length, Schinderhannes is only about 4 inches long.

Steinmann Institute/University of Bonn

Scientists have puzzled over the origins of the paired grasping appendages found on the heads of scorpions and horseshoe crabs. The researchers suggest that Schinderhannes gives a hint. Their appendages may be an equivalent to those found in the ancient predatory ancestor, Anomalocaris — even though creatures with those head structures were thought to have become extinct by the middle of the Cambrian Period, 100 million years before Schinderhannes lived.

Cretaceous Extinction Resonates Today

Signature of the End-Cretaceous Mass Extinction in the Modern Biota. 2009. A. Z. Krug, et al. Science 323: 767-771.

image

Scientists quantified the time of origin for 711 lineages of bivalves living in the oceans today, and converted them to evolutionary origination rates. In all but the highest-latitude locations, the team saw the clear signs of a strong increase in origination rates following the end of the Cretaceous.

Abstract: The long-term effects of mass extinctions on spatial and evolutionary dynamics have been poorly studied. Here we show that the evolutionary consequences of the end-Cretaceous [Cretaceous/Paleogene (K/Pg)] mass extinction persist in present-day biogeography. The geologic ages of genera of living marine bivalves show a significant break from a smooth exponential distribution, corresponding to the K/Pg boundary. The break reflects a permanent increase in origination rates, intermediate between the Mesozoic rate and the post-extinction recovery pulse. This global rate shift is most clearly seen today in tropical bioprovinces and weakens toward the poles.

Coupled with the modern geographic distributions of taxa originating before and after the K/Pg boundary, this spatial pattern indicates that tropical origination rates after the K/Pg event have left a permanent mark on the taxonomic and biogeographic structure of the modern biota, despite the complex Cenozoic history of marine environments.

Born This Day: Mary Leakey

Feb. 6, 1913 – Dec. 9, 1996

From the Minnesota State University site:

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

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

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

Image from HERE.

Oldest Fossil Evidence For Life Found

Fossil steroids record the appearance of Demospongiae during the Cryogenian period. 2009. G. D. Love et al. Nature 457: 718-721

Challengers of the Unknown © DC Comics

Scientists have found the oldest evidence for animals in the fossil record.

The researchers examined sedimentary rocks in south Oman, and found an anomalously high amount of distinctive steroids are produced by sponges that date back to 635 million years ago, to around the end of the last immense ice age.

The researchers argue that the discovery of the sponges is evidence for multicellular animal life beginning 100 million years before the Cambrian explosion that began about 530 million years.

According to Gordon Love, the climatic shock of the extensive glacial episodes of the Neoproterozoic era (1000-542 million years ago) likely caused a major reorganization of marine ecosystems, perhaps by irrevocably altering ocean chemistry.
"This paved the way for the evolution of animal feeders living on the seafloor," he said. "We believe we are converging on the correct date for the divergence of complex multicellular animal life, on the shallow ocean floor between 635 and 750 million years ago."

The steroids that Love and his colleagues observed in the Omani rocks are essential biochemicals present in the cell membranes of the sponges, and help provide the membranes with structural support. The sponges are a few millimeters in size, immobile, and were filter feeders existing on the seafloor. link

Born This Day: Alexandre Brongniart

Feb. 5, 1770 - Oct. 7, 1847.

Brongniart was a French mineralogist, geologist, and naturalist, who first arranged the geologic formations of the Tertiary Period (from 66.4 to 1.6 million years ago) in chronological order and described them.

He made the first systematic study of trilobites that became important in determining the chronology of Paleozoic strata (from 540 to 245 million years ago).

He helped introduce the principle of geologic dating by the identification of distinctive fossils found in each stratum and noted that the Paris formations had been created under alternate freshwater and saltwater conditions. image. From Today In Science History

Behold! Titanoboa!

Giant boid snake from the Palaeocene neotropics reveals hotter past equatorial temperatures. 2009. J.J. Head, et al. Nature 457: 71



Scientists have recovered fossils from a new 60-million-year-old South American snake, Titanoboa cerrejonensi. The size of its vertebrae suggest it weighed 1,140 kg and measured 13 m (42.7 feet) nose to tail tip. link

National Geographic has the details.

Australopithecus Had Jaws of Steel

The feeding biomechanics and dietary ecology of Australopithecus africanus. D. S. Strait, et al. 2009. PNAS. published online before print February 2, 2009.

Compressive stress in the cranium of Australopithecus africanus, an extinct early human, imposed by biting on the premolar teeth. Bright colors correspond to high stresses, and indicate that a bony pillar running alongside the opening of the nasal cavity acts as a strut that structurally reinforces the face against premolar loads.

New research reveals nut-cracking abilities in our 2.5-million-year-old relatives that enabled them to alter their diet to adapt to changes in food sources in their environment.

Using state-of-the-art computer modeling and simulation technology – the same kind engineers use to simulate how a car reacts to forces in a front-end collision – evolutionary scientists built a virtual model of the A. africanus skull and were able to see just how the jaw operated and what forces it could produce.

"We started with a CT scan of a skull that is one of the most complete specimens of A. africanus that we have," said Mark Spencer, researcher in ASU's Institute of Human Origins and a lead investigator on the project. This would be a later ancestor of Lucy – STS5 - who is affectionately known as "Mrs. Ples." The skull, discovered in 1947, has struts on the side of the nose, but no teeth. "We meshed those data with another specimen with teeth to make the virtual model of the bone and tooth structure.

"Then we looked at chimpanzees, who share common features with Australopithecus, and took measurements of how their muscles work and added that to the model. We were able to validate this model by comparing it to a similar model built for a species of monkey called macaques," Spencer explained.

The result illustrates forces absorbed by the cranial structure in simulated bite scenarios and how their unusual facial features were ideally suited to support the heavy loads of cracking hard nuts.

"This reinforces the body of research indicating that facial specializations in species of early humans are adaptations due to a specialized diet," said Spencer. "The enlargement of the premolars, the heavy tooth enamel and the evidence now that they were loading forcefully on the molars suggest the size of the objects were larger than the previously hypothesized small seeds and nuts. link

More Star-Spangled Dinos!

© Pete Von Sholly

More Star-Spangled Dinosaurs covers over at Pete Von Sholly’s Von Shollywood Blog.

Pete also features a great unseen Styracosaurus painting by Mark Hallet HERE.

Ancient Whales Gave Birth On Land

New Protocetid Whale from the Middle Eocene of Pakistan: Birth on Land, Precocial Development, and Sexual Dimorphism. Gingerich, et al. 2009. PLOS

Fossils of female Maiacetus inuus with near-term fetus in utero, as found in the field. The female's skull is shaded white (teeth brown), and other parts of her skeleton are shaded red. The single fetus, in birth position inside the mother whale, is shaded blue (teeth orange). UMMNH

Two newly described fossil whales---a pregnant female and a male of the same species--reveal how primitive whales gave birth and provide new insights into how whales made the transition from land to sea.

The 47.5 million-year-old fossils, discovered in Pakistan in 2000 and 2004, are the first discovery of a fetal skeleton of an extinct whale in the group known as Archaeoceti, and the find represents a new species dubbed Maiacetus inuus. (Maiacetus means "mother whale," and Inuus was a Roman fertility god.) The fetus is positioned for head-first delivery, like land mammals but unlike modern whales, indicating that these whales still gave birth on land.

Another clue to the whales' lifestyle is the well-developed set of teeth in the fetus, suggesting that Maiacetus newborns were equipped to fend for themselves, rather than being helpless in early life.

Male Maiacetus inuus. John Klausmeyer & Bonnie Miljour/UMMNH

The 8.5-foot-long male specimen, collected four years later from the same fossil beds, shares characteristic anatomical features with the female of the species, but its virtually complete skeleton is 12 percent larger overall, and its canine teeth or fangs 20 percent larger. Such size discrepancies are not uncommon among whales and their kin; in some species the females are larger, while in others the males are slightly to considerably bigger. The size difference of male and female Maiacetus is only moderate, hinting that the males didn't control territories or command harems of females.

Like other primitive archaeocetes, Maiacetus had four legs modified for foot-powered swimming, and although these whales could support their weight on their flipper-like limbs, they probably couldn't travel far on land.

"They clearly were tied to the shore," Gingerich said. "They were living at the land-sea interface and going back and forth."

Born This Day: Gideon Mantell

Feb. 3, 1790 – Nov. 10, 1852

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

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

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

Info and plate from HERE.

Died This Day: Ernst Mayr

July 5, 1904 - Feb. 3, 2005

Any student of biology, or anyone with an interest in the natural world, will be familiar with Ernst Mayr who passed away on February 3rd in Bedford, Mass. Born in Kempton, Germany he joined the American Museum of Natural History as a curator in 1931. In 1953 he left the museum to work at Harvard University where he stayed until his retirement in 1975.

While working on the problem of speciation in the birds of New Guinea, Mayr realized that the multitude of species and and subspecies that he saw could best be explained as being a snapshot of evolution in action. He suggested that new species could arise when the range of one species was fractured long enough for members in different parts of the range to evolve characters that would not allow individuals to reproduce when they were brought back together again. This lead to him developing the “biological species concept” in which species are defined as populations of interbreeding organisms rather than just a collection of characters. This idea, along with his theory of “allopatric speciation” was published in his book “Systematics and the Origin of the Species” (1942) and later contributed to the “Punctuated Equilibrium” theory of Niles Eldredge and Stephen Jay Gould.

Ernst Mayr was himself inspired by the work of geneticist Theodosius Dobzhansky on the fruit fly Drosophila melanogaster and his book “Genetics and the Origin of the Species” (1937). These two men, together with the paleontologist George Gaylord Simpson, combined the sciences of genetics, zoology and paleontology into what is now known as “the new synthesis” that provides the modern experimental underpinning to the concepts that Charles Darwin presented in his book, “On the Origin of the Species” .

For anyone interested in learning more about modern evolutionary theory I’d recommend Mayr’s recent book “What Evolution Is” (2002). It’s written in an engaging and readable format from the perspective of someone who’s thought about evolution all his life.