paleontology
laelaps | April 8, 2008
The skull of Raeticodactylus filisurensis. From Stecher 2008.
On April first I wrote about heterdonty in lizards, dinosaurs, and crocodylians, but it was no April Fool's Day joke; mammals aren't the only animals that have differently-shaped teeth throughout their jaws. I should have waited just a little bit longer to write the post, though, because a new genus of Upper Triassic pterosaur from Switzerland named Raeticodactylus filisurensis has just been announced in the Swiss Journal of Geosciences.
Raeticodactylus is certainly a strange creature. It has heterodont teeth, a crest, and shows…
gregladen | April 7, 2008Ever since 3,599 years ago humans have been asking the question "Why did our furry elephant go extinct?"
What caused the woolly mammoth's (not to be confused with the also-woolly mastodon) extinction? Climate warming in the Holocene might have driven the extinction of this cold-adapted species, yet the species had survived previous warming periods, suggesting that the more-plausible cause was human expansion.
The woolly mammoth went extinct less than four thousand years ago. The bones of miniaturized woolly mammoths have been found in Siberia dating to about 3,600 years ago. Indeed,…
gregladen | April 7, 2008Fifth grader Kenton Stufflebeam is smarter than the Smithsonian Institution. Since 1981, the Tower of Time exhibit has indicated that the Precambrian is an "era" ... when in fact it is not an actual era.
The student informed the museum, and now the Smithsonian is working on plans to paint over the word "era."
[source]
laelaps | April 7, 2008
Dr. Robert Bakker is one of the most famous paleontologists working today, an iconoclastic figure who has played a leading role of rehabilitating our understanding of dinosaurs from the inception of the "Dinosaur Renaissance" through the present. He is currently the curator of paleontology for the Houston Museum of Natural Science and the Director of the Morrison Natural History Museum in Colorado, and has recently been involved in the study of the hadrosaur mummy "Leonardo." In 1986 he published the classic book The Dinosaur Heresies, fully bringing his revolutionized vision of dinosaurs to…
gregladen | April 6, 2008
Grrrrrrrrrrrrr....
Welcome to the Lucky 13th Edition of The Boneyard ... the Web Carnival about Bones and Stuff.
"The Boneyard is a blog carnival covering all things paleo, from dinosaurs to pollen to hominids and everywhere in between. It's held every two weeks (the 1st and 3rd Saturday of the month), traveling around to a different blog for each installment, connecting some of the best blogging on ancient life."
The previous edition of The Boneyard is here, at Dragon's Tales. The next edition of The Boneyard will be Here at Archaeozoology. If you would like to submit an entry to the next…
laelaps | April 6, 2008Camarasaurus is an unappreciated sauropod. It wasn't the heaviest or longest of the earth-shaking dinosaurs, but the blunted skull and large teeth of the Jurassic sauropod indicate that it had a different lifestyle than the more famous Diplodocus and Apatosaurus. In 1920, paleontologists at the AMNH created a skeletal and muscular reconstruction of the dinosaur, Camarasaurus being proportionally bulkier for its size than other sauropods then known.
The reconstruction of a model of Camarasaurus had another purpose, as well. In 1908 Oliver Hay published a paper advocating a sprawling, crocodile…
laelaps | April 5, 2008Last week I looked at reconstructions of Diplodocus (both humorous and scientific) by Oliver Hay and G.G. Simpson. After rifling through my collection of papers, I came upon a description of Diplodocus by H.F. Osborn and thought I would continue the trend I had set earlier.
In 1897, the AMNH sent a field crew to look over the famous Como Bluff quarries that were so productive for O.C. Marsh in previous years, and although the site was considered exhausted Barnum Brown quickly came across a Diplodocus femur. There was more than just a femur, however, and soon J.L. Wortmann was supervising the…
laelaps | April 5, 2008
This coming Monday I'll be putting up the first in what I hope will be a long series of interviews with paleontologists, and I'm setting the bar high with Bob Bakker. The predatory habits of Tyrannosaurus, the relationship of Dracorex to Pachycephalosaurus, and the current evolution v. creationism controversy are all discussed (plus much more), so be sure to check back on Monday to see the full interview.
I don't know how often I'll be able to post interviews (that will depend on the paleontologists), but I've got a few other people in mind. Who else would you like to hear from? I'm…
gregladen | April 4, 2008A very important and truly wonderful paper in Nature described a tour-de-force analysis of the Mammalian Evolutionary Record, and draws the following two important conclusions:
The diversification of the major groups of mammals occurred millions of years prior to the KT boundary event; and
The further diversification of these groups into the modern pattern of mammalian diversity occurred millions of years later than the KT boundary event.
The KT boundary event is the moment in time when a ca. 10 km. diameter object going very fast hit the earth in the vicinity of the modern Yucatan,…
laelaps | April 3, 2008
A famous illustration of a swamp-bound "Brontosaurus" by Charles R. Knight. From Dinosaurs by William Diller Matthew (1915).
As I've been slowly reorganizing the mass of technical papers on my computer (1,600+ and counting), I've occasionally blundered into an old paper or two that I had forgotten about. I've already used two to create a somewhat superficial post about reconstructions of phytosaurs earlier today, so I'll run with the theme of paleontological reconstruction with Oliver Hay's ideas about the lifestyle of Diplodocus.
Published in 1908, the article seems like a good textual…
laelaps | April 3, 2008
The reconstructions of Brachysuchus and Rhytiodon compared. From Case 1931.
In the winter of 1931, University of Michigan paleontologist E.C. Case commissioned artist Carleton W. Angell to bring two phytosaurs to life. Even though phytosaurs as a group were still poorly defined, Case recognized that there seemed to be at least two morphotypes represented by different skull reconstruction. According to Case's summary, Rhytiodon (now called Rutiodon) represented a more lightly-built form that probably fed upon fish, while the more massive Brachysuchus (now often called Angistorhinus)…
laelaps | April 1, 2008One of the first things I was ever told about what makes reptiles different from mammals was that reptile teeth were the same all throughout their jaws (called a homodont condition) and that mammal teeth were different throughout their jaws (called a heterodont condition). The fact that mammals had fur, mammary glands, and had a high metabolism/constant body temperature were all obvious, but I had never heard about the difference in teeth. That was elementary-school simplification, though, and the fact of the matter is that the distinction is not so sharp. There have been both homodont…
laelaps | March 31, 2008Someone has been kind enough to upload "Dinosaurs!: A Fun-Filled Trip Back in Time!" to YouTube and it has definitely made me feel a bit nostalgic. Now the trouble is that I've got "Mesozoic Mind" stuck in my head...
laelaps | March 31, 2008I love the concept of paleo-labs in museums where visitors can watch fossil preparators and paleontologists work on fossils brought in from the field (I've heard that the one at the Page Museum in L.A. is the best, although the one at the Academy of Natural Sciences isn't too shabby, either). If you live near Los Angeles and enjoy such exhibits, too, then you're in luck; the L.A. County Natural History Museum just opened the "Thomas the T. rex Lab" where you can see researchers working on the skeleton of a young Tyrannosaurus.
The preservation and restoration of "Thomas" is part of a larger…
laelaps | March 31, 2008
The skeleton of "Nichollsia" borealis. The left forelimb and scapula were accidentally destroyed during excavation, but otherwise the skeleton was kept intact. From Druckenmiller & Russell 2008.
Last week I mentioned that a very well-preserved Early Cretaceous plesiosaur named "Nichollsia" borealis* was recently described in the journal Palaeontographica Abteilung A, and one of the authors was kind enough to send a scan of the paper to me. What follows is a brief summary of the significance of the find.
*I put the genus name in quotes as Nichollsia is occupied by an isopod, and a new…
laelaps | March 29, 2008
"Leonardo," the mummy dinosaur.
News of the well-preserved skeleton of the Edmontosaurus "Dakota" have been featured prominently in the news lately, but according to an announcement made this weekend, another exquisitely-preserved hadrosaur is going to be put on public display this coming September. "Leonardo," a beautifully-preserved Brachylophosaurus, will be presented to the public starting September 19, 2008 in the exhibit "Dinosaur Mummy CSI: Cretaceous Science Investigation" at the Houston Museum of Natural Science. Eventually the exhibit will tour the country, but if you want to…
clock | March 28, 2008Imagine: An Interview with Svante Paabo:
Svante Paabo works on the edge of what's possible. He ignites our imagination, unlocking tightly held secrets in ancient remains. By patiently and meticulously working out techniques to extract genetic information from skin, teeth, bones, and excrement, Paabo has become the leader of the ancient DNA pack. Sloths, cave bears, moas, wooly mammoths, extinct bees, and Neanderthals--all have succumbed to his scrutiny.
Paabo (see Image 1) broke ground in 1985, working surreptitiously at night in the lab where he conducted his unrelated PhD research, to…
laelaps | March 28, 2008
The skull of Mosasaurus hoffmani. Lingham-Soliar 1995.
On my first trip to the Inversand marl pit in Sewell, New Jersey, I didn't find the wonderfully preserved Dryptosaurus skeleton I had been dreaming of. I come across a number of bivalve shells and geologically younger sponges, but other than a few scraps of "Chunkosaurus," my excavations didn't yield very much. Before my paleontology class left the site, though, we took a walk by the spoil piles, great green mounds of sediment that had already been mined for glauconite. It had recently rained, and little pillars revealed fragmentary…
laelaps | March 27, 2008
The skull and mandible of Guarinisuchus.
After the end-Cretaceous extinction, an "empty" world was left to fill up. The non-avian dinosaurs were gone, as were the mosasaurs, ammonites, pterosaurs, and other creatures. Indeed, in marine environments the large Mesozoic predators were eliminated in the extinction event, allowing sharks and crocodiles to evolve and diversify now that they were no longer any mosasaurs patrolling the waters. One such crocodylian that moved into open ecological space was Guarinisuchus munizi, just described in the Proceedings of the Royal Society B.
Although…
laelaps | March 27, 2008According to a Daily Mail article released yesterday, a 19 lb. jawbone from an extinct elephant relative was found in an unmarked package in a bus compartment. There isn't much else to the story, except that the mandible was misidentified by the "expert" called to look at photos of the fossil (and hence the error was repeated in the newspaper). According to the report, the jaws were from a Triceratops;
Pablo de la Vera Cruz, an archeologist at the National University in Arequipa, said examined police photos of the fossil. He said: "The jawbone that was found could be from a triceratops, even…