paleontology
laelaps | October 20, 2009[Note: Once again I have found myself with too many writing projects and too little time. Expect something substantial to appear here tomorrow, but for now enjoy an old tale about the "Nevada Giant."]
The role petrified bones and footprints have played in the origin of myths and legends has been recognized since the 19th century, but it has only been recently that the connection between fossils and mythology has been appreciated as a subject worthy of careful scrutiny. (See The First Fossil Hunters, Fossil Legends of the First Americans, and American Monster). It should be kept in mind,…
gregladen | October 20, 2009To answer that question briefly, it is really really old if you mean "how old are the oldest rocks that are exposed by the Grand Canyon," and it is probably just a few million years old (5 or 6 by some estimates) if you mean "how long did the canyon itself take to form."An African peneplain elevated by doming along the Eastern Rift Valley. The original surface, once flat but now raised as "mountains" in the distance, is shown by the dotted line.
A repost
But Creationists, of course, have a different story, especially young earth creationists. I'm not going to recount it here. If you want to…
laelaps | October 16, 2009Three restorations (top, left side, and bottom) of the skull of Andrewsiphius. From the Journal of Paleontology paper.
During the past 30 years the evolution of fully aquatic whales from terrestrial ancestors has gone from one of the most enigmatic evolutionary transitions to one of the best documented. Evidence from the fossil record, genetics, and embryology have been combined to document how early whales walked into the sea, but what often has gone unnoticed is the diversity of early whales. In a new paper published in the latest issue of The Journal of Paleontology, cetacean experts J.G.M…
laelaps | October 15, 2009My new favorite illustration from the technical literature; a baseball player compared to the glyptodont Doedicurus clavicaudatus. From the Proceedings of the Royal Society B paper.In the introduction to his most famous work, On the Origin of Species by Means of Natural Selection, the Victorian naturalist Charles Darwin began by writing;
WHEN on board H.M.S. 'Beagle,' as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to…
laelaps | October 12, 2009
I love flipping through old paleontology textbooks. Many times the text and images inside them have been reproduced from other sources or bear a close resemblance to similar titles published at about the same time, but every now and then I find something really unusual. Such was the case while I was skimming through H.F. Cleland's 1916 Geology: Physical and Historical.
While looking for out-of-date ideas on the origin of the first tetrapods I came across a very strange restoration of Dimetrodon (illustration to the left). Dimetrodon was a spenacodontid synapsid, an odd creature that, despite…
laelaps | October 9, 2009Chucking stones at baboons; the first hominin passtime? From The Making of Man.For the Australian anatomist Raymond Dart, the fossilized bones scattered among the caves of South Africa were testimonies to the murderous nature of early humans. The recovered skulls of baboons and our australopithecine relatives often looked as if they had been bashed in, and Dart believed the bones, teeth, and horns of slain game animals were the weapons hominins used to slaughter their prey. (He gave this sort of tool use the cumbersome name "osteodontokeratic culture.") Our origins had not been peaceful; Homo…
gregladen | October 7, 2009A new investigation of the sedimentology and ichnology of the Early Jurassic Moyeni tracksite in Lesotho, southern Africa has yielded new insights into the behavior and locomotor dynamics of early dinosaurs.
The tracksite is a pont bar in an old river that had a lot of variation in slope and the nature of the sediment on which one would walk. There are trackways of numerous different kinds of dinosaurs that walked across this surface over a very short period of time (of several days or a bit longer). The different dinosaurs responded to the different surfaces differently. That is not a…
laelaps | October 7, 2009
I have often been teased for my habit of carrying a science book wherever I go. ("That's such a Brian thing," an acquaintance once remarked.) If I am going to be waiting for someone or have a few minutes to spare here or there I like to have something to read to fill up the time. It's either that or fiddle around with Tetris on my cell phone. Some people have told me that this manifestation of bibliophilia makes me seem antisocial,* but I cannot break the habit. I have been toting around science stuff wherever I go from a very young age.
*[My favorite instance was when I was told to "Make…
laelaps | October 6, 2009When I wrote about the public unveiling of Ardipithecus ramidus (or "Ardi" to the public) last week I contrasted the description of the hominin with the bombastic rollout given to the lemur-like fossil primate "Ida" (Darwinius masillae) this past May. In the latter case it was clear that a media production company rushed the scientific process and overhyped the conclusions presented to the public, but now there are questions about the relationship between the scientists who described "Ardi" and the Discovery Channel.
This coming Sunday the Discovery Channel will air a special called "…
laelaps | October 3, 2009A trio of dinosaurs at the Utah Museum of Natural History in Salt Lake City, Utah. An Allosaurus (left) attacks a Camptosaurus (right) while another Allosaurus looms in the background.
laelaps | October 2, 2009Two restorations of "Ardi", a 45% complete skeleton of Ardipithecus ramidus published in this week's issue of Science. Restorations (including the full skeletal restoration below) by artist Jay Matternes.The stories of "Ida" and "Ardi" could hardly be more different.
Ida was a lemur-like primate that lived 47 million years ago in an area that is now Messel, Germany. Ardi was much closer to us; she was one of the earliest hominins and lived 4.4 million years ago in what would become known as Ethiopia.
When the bones of Ida were discovered they were held in a private collection for years before…
laelaps | October 1, 2009It's Ardipithecus day! No, not that one, but the other one, Ardipithecus ramidus, which paleoanthropologists have been studying for the past 15 years. Over 45% of the skeleton of this hominin was found in the early 1990's, but outside of a brief initial description no further details about Ardipithecus ramidus had been published until today.
Later this afternoon Science will launch a webpage containing multiple print articles and online features chock-full of details about this early hominin. (Word has it that an entire University of California Press volume will be devoted to Ardipithecus…
laelaps | September 28, 2009
As some of you may recall, last week I posted a list of new and forthcoming books written by science bloggers. I tried to include all the authors and titles I could think of, but there was one book that I intentionally left off the list; my own.
I am now proud to announce that my first book, Written in Stone, will be released by Bellevue Literary Press in the fall of 2010. In it I tell the stories of some of the most magnificent evolutionary transitions in the vertebrate fossil record, such as the evolution of birds from feathered theropod dinosaurs and whales from land-dwelling ancestors,…
laelaps | September 27, 2009A shot of the scenery taken on the way back from an early-morning hike to the Red Fleet Reservoir dinosaur track site in northern Utah.
laelaps | September 24, 2009
Scotland did not have much to offer 19-year-old Andrew Geddes Bain. Both his parents had died when he was a child, and even though he was educated his job prospects were few. When his uncle, Lieutenant Colonel William Geddes, left for South Africa in 1816 young Andrew decided to go with him to the British empire's southern frontier.
Once he arrived there, Bain found work where he could. He worked as a saddler, an explorer, an ivory trader, a soldier, and a road-builder, but in 1837 Bain read a book that would inspire him to look a little bit closer at the rugged landscape around him. That…
gregladen | September 17, 2009The evolutionary history of mammals can be reviewed as the evolutionary history of tooth loss. The early mammals had many teeth, and every now and then in evolutionary time, a tooth is lost wiht subsequent species arriving from that n-1 toothed form having that smaller number of teeth. With ver few exceptions, no mammals have added a tooth during the history of mammals. (Excepting maybe the very very earliest period, but probably not.)
Well, the loss of enamel itself is also an evolutionary trend in mammal history, and recent research published in PLoS Genetic associates genetic changes…
laelaps | September 16, 2009Yesterday I questioned the path by which Simon Conway Morris and James Valentine, two evolutionary biologists, came to appear in the new creationist film Darwin's Dilemma. Created by Illustra Media, a film company that has worked closely with the Discovery Institute, the film claims that the "Cambrian Explosion" provides evidence for intelligent design. I now have more information.
Simon Conway Morris was interviewed for the film. In an e-mail by Lad Allen, the producer of Darwin's Dilemma, the filmmaker provided evidence that he had interviewed Conway Morris on November 14, 2006. The…
laelaps | September 16, 2009Considering the fossils of the Cambrian, the oldest fossil-bearing rocks known during his time, Charles Darwin wrote the following in the 6th edition of On the Origin of Species;
... it cannot be doubted that all the Cambrian and Silurian trilobites are descended from some on crustacean, which must have lived long before the Cambrian age, and which probably differed greatly from any known animal. ...
... if the theory be true, it is indisputable that before the lowest Cambrian stratum was deposited long periods elapsed, as long as, or probably far longer than, the whole interval from the…
clock | September 15, 2009
Today PLoS ONE published a paper describing a very cool new fossil of a sauropod from Niger - an exquisitely preserved, almost complete skeleton. Of course, you can read it for free at:
A New Basal Sauropod Dinosaur from the Middle Jurassic of Niger and the Early Evolution of Sauropoda:
Background
The early evolution of sauropod dinosaurs is poorly understood because of a highly incomplete fossil record. New discoveries of Early and Middle Jurassic sauropods have a great potential to lead to a better understanding of early sauropod evolution and to reevaluate the patterns of sauropod…