paleontology
laelaps | February 15, 2010A reconstruction of Smilodon, photographed at the American Museum of Natural History.
When it comes to animals, encyclopedias often present us with generalized descriptions. Where a creature lives, what color it is, what it eats, and other tidbits of information are listed to distinguish one species from another, but what is lost is an appreciation of variation. Be they genetic, anatomical, or behavioral, variations are grist for natural selection's mill, and if you study any species in detail it becomes apparent that individuals differ considerably over space and through time.
This was true…
laelaps | February 11, 2010A reconstruction of Smilodon, photographed at the American Museum of Natural History.
laelaps | February 8, 2010
Almost two decades ago vertebrate paleontologist Bruce MacFadden published his monograph Fossil Horses, an instant classic that was as much about new approaches in paleontology as the equids considered in the book. For over a century the family history of horses had been depicted as some of the best, most-accessible evidence for evolution the fossil record had to offer, and MacFadden's book provided an excellent synthesis of what had been discovered. Since the publication of Fossil Horses, however, no other books have appeared to follow-up on what MacFadden presented. Brief nods and short…
grrlscientist | February 5, 2010tags: evolutionary biology, paleontology, taphonomy, plumage color, feathers, color, melanin, eumelanin, phaeomelanin, dinosaurs, theropod, paravian, avialae, fossils, Anchiornis huxleyi, ornithology, birds, researchblogging.org,peer-reviewed research, peer-reviewed paper
New research reveals that recently-described 155-million-year-old Anchiornis huxleyi,
a woodpecker-like dinosaur the size of a modern-day domesticated chicken,
had black-and-white spangled wings and a rusty red crown.
Image: Michael DiGiorgio, Yale University [larger view]
Fig. 4. Reconstruction of the plumage color of…
laelaps | February 3, 2010A restoration of Titanoboa (foreground) in its natural setting. (By Jason Bourque, image from Wikipedia.)
When I was growing up I used to spend hours poring over the Time/Life series of nature books in my little library, absolutely enthralled by images of strange creatures from all over the world, but one photograph was particularly arresting. A grainy black-and-white double-page spread showed an anaconda that had wrapped its crushing coils around a caiman and a tree, slowly squeezing the life out of the crocodylian. Without any frame of reference for size it was easy to envision the two…
grrlscientist | February 2, 2010tags: science, iPhone Apps, technology, education, dinosaurs, American Museum of Natural History, AMNH, streaming video
Introducing the first official iPhone app from the American Museum of Natural History, DINOSAURS: American Museum of Natural History Collections. This app lets paleontologists of all ages explore the Museum's famous fossil halls in depth.
DINOSAURS: American Museum of Natural History Collections contains more than 800 images from the Museum's archive, woven together to create a striking image of the world's most famous dinosaur, the Tyrannosaurus rex.
Double-tap or pinch to…
milhayser | February 2, 2010
Fossils offer a rare glimpse into the past, as lifeforms we could scarcely imagine are preserved long after their day in the sun. But fossilization requires very specific conditions, and few things that die are turned to stone. On Living the Scientific Life, GrrlScientist presents Haplocheirus, a theropod with "three toes, a birdlike keel-shaped chest and a long beak," but also "small teeth, like a dinosaur." This creature bolsters the idea that birds evolved from dinosaurs through independent lines. On Not Exactly Rocket Science, Ed Yong discusses fossilized dinosaur fuzz, which…
laelaps | February 2, 2010A grizzly bear (the black dot in the middle of the photo) walking near the treeline in Yellowstone's Hayden Valley.
The quiet of my evening wildlife watching was suddenly broken by a thick Boston accent. "Oh my gawd! Look! It's a grizz! That's the last animal I needed to see! It's a grizz!"
He was right. Lumbering across the valley was a big dark shape that could only be a bear. It was not very close, being little more than a dot moving along the distant treeline, but through the zoom lens of my camera it was just possible to make out the hump that distinguishes black bears from grizzly bears…
grrlscientist | February 1, 2010tags: evolutionary biology, paleontology, fossils, fossilization, fossil forensics, Taphonomy, taxonomy, zoology, deep time, paleoceanography, amphioxus, Branchiostoma lanceolatum, lamprey, Lampetra fluviatilis, chordates, researchblogging.org,peer-reviewed research, peer-reviewed paper
Three rotting Amphioxus heads.
A sequence of images showing how the characteristic features of the body of amphioxus, a close living relative of vertebrates, change during decay. Colours are caused by interference between the experimental equipment and the light illuminating the specimens.
Image: Mark…
grrlscientist | January 30, 2010tags: evolutionary biology, convergent evolution, paleontology, taxonomy, zoology, basal birds, theropods, dinosaurs, ornithology, birds, Alvarezsauroidea, Haplocheirus sollers, Maniraptora, Archaeopteryx, researchblogging.org,peer-reviewed research, peer-reviewed paper
A Newly Discovered Basal Alvarezsauroid Theropod from the Early Late Jurassic.
Artwork: Portia Sloan [larger view]
DOI: 10.1126/science.1182143
A long-standing scientific debate focuses on the origins of birds: did they evolve from reptiles or dinosaurs? Currently, most scientists think that birds are modern dinosaurs, but…
grrlscientist | January 28, 2010tags: evolutionary biology, fossils, feathers, plumage color, color, dinosaurs, theropods, Sinosauropteryx, Sinornithosaurus, birds, Confuciusornis, melanosomes, phaeomelanosomes, eumelanosomes, keratinocytes, SEM, scanning electron microscopy, 10.1038/nature08740, researchblogging.org, peer-reviewed research, peer-reviewed paper
Reconstruction of two Sinosauropteryx, sporting their orange and white striped tails.
Artwork by Chuang Zhao and Lida Xing [larger view]
DOI: 10.1038/nature08740
While looking at museum dioramas that feature dinosaurs, I often overhear people asking "How do they…
laelaps | January 20, 2010A Pachycephalosaurus, photographed at the North Carolina Museum of Natural Sciences.
laelaps | January 20, 2010A ring-tailed lemur (Lemur catta), photographed at the Bronx Zoo.
Who doesn't love lemurs? The strepsirrhine primates, or wet-nosed cousins of ours, are favorite documentary subjects and extremely popular zoo attractions. And, in one of those bits of zoological trivia that everyone knows, lemurs only live on the island of Madagascar off Africa's southeastern coast. The question is how they got there.
Documenting the paths of animals during geological history is not an easy task. In the days before scientists understood plate tectonics, land bridges, now sunk beneath the ocean, were often used…
laelaps | January 19, 2010The restored lower jaw of Arcanotherium (formerly Numidotherium savagei). (From Delmer, 2009)
Unlike the folks at this past weekend's ScienceOnline 2010 meeting, fossils don't come with nametags. The identification of preserved bits of ancient life relies upon careful comparison with what is already known, a task made all the more difficult for vertebrate paleontologists by the fragmentary nature of many of their subjects. Scraps of bone given one name could turn out to be parts of another partial skeleton given another name, or other bits of bone attributed one name could turn out to be…
laelaps | January 18, 2010A restoration of Acrocanthosaurus, photographed at the North Carolina Museum of Natural Sciences.
laelaps | January 12, 2010Restoration of the skull of Thylacoleo. From The Ancient Life History of the Earth.
Thylacoleo was one strange mammal. A close relative of living koalas, kangaroos, and wombats, the largest species of Thylacoleo were lion-sized carnivores that stalked the Australian continent between 2 million and 45 thousand years ago. Despite its popular nickname "marsupial lion", however, Thylacoleo was quite different from any feline predator. Even though its long forelimbs were tipped with retractable claws its skull more closely resembled that of a koala, with curved incisors set in front of a pair of…
laelaps | January 11, 2010Pterosaur fans, rejoice! Today marks the launch of Pterosaur.net, a website entirely dedicated to the famous flying reptiles. Put together by an all-star team of paleo bloggers, it is the best resource for information on pterosaurs available on the web. Go check it out!
laelaps | January 8, 2010A comparison between the complete skull of a Glyptodon and the skull fragments of a fetal specimen. (From Zurita et al, 2009)
Early in 2009 a team of paleontologists led by Philip Gingerich announced the discovery of a baby archaeocete (early whale) embedded inside the skeleton of an adult of the same species. Since these fossils represented a new species of fossil whale to boot the story was immediately picked up by news outlets, but less well-publicized was another discovery made later the same year. In the pages of Comptes Rendus Palevol paleontologists Alfredo Zurita, Angel Mino-Boilinia…
laelaps | January 6, 2010
Tiktaalik is practically a household name. Since its description in 2006 the flat-headed "fishapod" has appeared in books, on t-shirts, and has even starred in its own music video. Hailed as a "missing link", Tiktaalik has become a poster child fossil for evolution, but it is hardly the first such creature to be given this honor.
Way back in the 1840's, well over a decade before Charles Darwin's On the Origin of Species was published, the Victorian anatomist Richard Owen was mulling over the concept of transitional forms. He was not so much thinking about actual fossils as the way anatomical…
laelaps | January 5, 2010A restoration of Mammalodon by Brian Choo (published in Fitzgerald, 2009).
In the introduction to his 1883 lecture on whales, the English anatomist William Henry Flower said;
Few natural groups present so many remarkable, very obvious, and easily appreciated illustrations of several of the most important general laws which appear to have determined the structure of animal bodies, as that selected for my lecture this evening. We shall find the effects of the two opposing forces--that of heredity or conformation to ancestral characters, and that of adaptation to changed environment, whether…