paleontology
laelaps | February 9, 2008Tonight I finished Rudwick's Georges Cuvier, Fossil Bones, and Geological Catastrophes, and I certainly feel that I have a better understand of Cuvier's work than I did previously (although the subject of his embranchments and debates with Geoffrey only received a fleeting mention). What is truly curious, though, is that Cuvier was not a biblical literalist and yet did not seem to favor a mechanism by which the various unique fossil taxa he described could have come into existence. He noted that an "age of reptiles" likely preceded an "age of mammals" (divided by a catastrophic revolution…
laelaps | February 8, 2008The American mastodon (Mammut americanum), illustrated in one of Cuvier's memoirs.When I taking biology in high school science seemed so simple. Lyell was a uniformitarian hero, Cuvier was a brillant anatomist (but sadly a narrow-minded catastrophist), Charles Darwin was the hero of all biology, and Lamarck was the official whipping boy of evolutionary science, the deconstruction of his ideas receiving more time than Darwin's theory of evolution by natural selection! In the years following my graduation in 2001 I didn't think too much about the issue, the work of naturalists who lived…
laelaps | February 6, 2008Bora just notified everyone to a bit of a paleontological challenge; the blog A natural history of Runswick Bay has an enigmatic fossil that seems to be reminiscent of a belemnite with a surrounding body impression, but the experts contacted about the fossil were unable to figure out what it might be. (I'm not suggesting that it is in any way related, but the fossil does remind me of Dickinsonia, an enigmatic fossil that's been interpreted in a number of ways by various researchers.) If you think you know what it is, though, head on over to A natural history of Runswick Bay and throw in your…
laelaps | February 5, 2008Update: The paper this post discusses is available online and is open access. It can be found here.
A new ScienceDaily piece reports on new molecular clock data that suggests modern birds have an "ancient origin" about 100 million years ago. My first thought upon reading the brief article was "This is news?" yet the details of what the paper actually says is going to be important in any discussion of the results.
I haven't read the actual paper yet, but article notes that the authors are referring to the diversification of modern birds, or Neornithes (see comments below, & thank you to…
laelaps | February 5, 2008
Yesterday was a good day as far as books went; I read G.G. Simpson's Splendid Isolation from cover-to-cover, two review copies arrived in the mail, and a book I've long been wanting to read also arrived at my door. That book is Johannes Weigelt's Recent Vertebrate Carcasses and their Paleobiological Implications, first published in 1927 but translated by Judith Schaefer and re-released in 1989. I haven't gotten a chance to dive into it yet, but it is an absolutely beautiful book, and even though the subject matter may be a bit macabe it has already inspired me.
Lately I've been thinking of…
laelaps | February 4, 2008The new crocodylian Montealtosuchus arrudacamposi. [Image source].Living crocodylians have often been referred to as "living fossils," creatures that have survived "virtually unchanged" for hundreds of millions of years. In truth, crocodylians as we recognize them today (i.e. aquatic ambush predators) first appear in the fossil record during the Jurassic (see comment below), but there was a much wider diversity of crocodylians during past epochs that were just as interesting (and even terrifying) as any dinosaur.* In the Bauru Basin of Brazil, for instance, the remains of at least five…
laelaps | February 4, 2008
The above photograph is of the forelimb claws of the giant ground sloth Megalonyx wheatleyi, first named by E.D. Cope in 1871. The genus name for this animal was assigned to a similar animal at the close of the previous century, however, Megalonyx first being assigned to fossils that first found their way into the possession of Thomas Jefferson around 1797. Jefferson first inferred the giant claws to be from some gigantic, ancient big cat,* but shortly after he formally described the find it was compared with the giant sloth Megatherium that Cuvier had described earlier. The similarities…
laelaps | February 2, 2008
Over the course of evolutionary history there have been a number of animals that have sported elongated neural spines, the structures sometimes aiding in the support of a hump (as in bison) and other times as the framework for a great sail (as in Spinosaurus). Of the group of "sail-backed" and "bison-backed" animals, the pelycosaur Edaphosaurus (the spines of which are pictured above) are unique, and the presence of transverse bars arranged on either side has long vexed paleontologists.
Charles R. Knight's sculpture of "Naosaurus" with a revised Edaphosaurus head. Courtesy of Dan Varner.…
laelaps | February 1, 2008The new crocodylian Montealtosuchus arrudacamposi. [Image source].I guess this one slipped by without getting proper attention. In October of 2007 research described a new genus of species of crocodylian, Montealtosuchus arrudacamposi (pictured above) in the journal Zootaxa. It was a late Cretaceous member of the Peirosauridae found in Bauru Basin, Brazil, although it was only one representative of a larger diversity of crocodylians from the location that also included notosuchids, sphagesaurids, baurusuchids, and trematochampsids. Unfortunately the paper is behind a subscription wall (the…
laelaps | February 1, 2008
Smilodon is perhaps the most famous of all the saber-toothed cats, but the level of notoriety it has received has led to a number of misunderstandings. As a child I remember hearing in a documentary (complete with somewhat hokey stop-motion giant sloths) that sabercats became extinct because their teeth grew so long that they could not close their mouths. I did not know it at the time, but this fallacious idea had been around for quite some time, and was quite surprised to find an effective refutation of it when I read G.G. Simpson's popular book The Meaning of Evolution (1950);
The…
clock | January 31, 2008Aetosaurs. No, I have not heard of them until now. But that does not matter - the big story about them today is the possibility - not 100% demonstrated yet, to be fair - that some unethical things surround their discovery and naming. And not just Aetosaurs. Some other fossils as well.
As I am not on the inside loop of the story, you need to first read the background story on Aetosaurs by Darren Naish - Part 1 and Part 2.
Then, carefully read Darren's today's post and responses by Laelaps, Cryptomundo and Paleochick.
For the ethical side of the story, read Janet's take.
For the gory…
gregladen | January 31, 2008
Proposals to give the latter part of the present geological period (the Holocene) a new name ... the Anthropocene ... are misguided, scientifically invalid, and obnoxious. However, there is a use for a term that is closely related to "Anthropocene" and I propose that we adopt that term instead.
The pithy title of the paper making this proposal is "Are we now living in the Anthropocene" (sic: no question mark is included in this title, enigmatically).
It is not an entirely stupid idea. The paper argues that there are major changes of the type often used to distinguish between major…
laelaps | January 30, 2008Update: Darren has now posted a more detailed summary of this controversy. Other bloggers will likely weigh-in on the subject throughout the day, and I'll soon have something up on why the issue has gotten to the point of appearing in Nature rather than being settled earlier.
Some time ago Darren posted two posts on aetosaurs (part 1 and part 2), cryptically hinting that Spencer Lucas and others at New Mexico Museum of Natural History and Science might have been involved in the claim-jumping of research involving these ancient crurotarsians. Now the story has come out into the open and an…
laelaps | January 30, 2008If you're going to be in the Rockford, Illinois area (or within a reasonable distance of it) on March 1st and 2nd, the Burpee Museum is going to be host to a paleo-festival that you won't want to miss out on. Over the course of two days there will be activities and events for both children and adults, and I have to say that the lecture program they have set up looks pretty awesome. Here's who will be speaking at the festival;
Philip Currie- Chinese Theropods and Mapusaurus
Jack Horner- Dinosaur Ontogenies
Eva Koppelhus - Paleoenvironment of Dinosaur Provincial
Jim Kirkland- Cretaceous Utah…
grrlscientist | January 29, 2008tags: Jennifer A. Clack, 2008 Daniel Girault Elliot medal, National Academy of Sciences, zoology, evolutionary biology, paleontology
The National Academy of Sciences's 2008 Daniel Girault Elliot medal.
I just learned that Jennifer A. Clack, ScD, FLS, Professor and Curator of Vertebrate Palaeontology and Acting Director of the University Museum of Zoology in Cambridge, UK, been awarded the 2008 Daniel Girault Elliot medal by the National Academy of Sciences.
The medal recognizes excellence in zoology or paleontology during a three to five year period of time, and the list of past…
laelaps | January 28, 2008The skeleton of an Irish Elk (Megaloceros giganteus) at the AMNH.Discussions of mass extinctions nearly always give rise to heated debates as to the mechanism(s) behind the disappearance of so many taxa in a short amount of time, and one of the most active debates still surrounds the extinction of Pleistocene megafauna. All over the world the extinction of large animals appears to be correlated with the movements of our own species, Homo sapiens, into new territories. Disease and climate change have their own parts to play, the "Overkill Hypothesis" is perhaps the most popular explanation for…