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New diary series I'm working on, meant to spur an interest and convey information on my field.

One dinosaur for each week!

Dinosaurs kick ass--we've known it ever since we were children. Many of us were (and some still are) filled with wonder as we stared upward at the massive skeletons of archaic monsters that lived millions of years in the past, each giving their own glimpse into life's history.

The era of non-avian dinosaurs lasted just over 160 million years. That's a one, a six, and seven zeros. If you were to compress one thousand years into a single day, the dinosaur-dominated world would  have lasted 438 years.

They were one of the most biologically successful creatures of all time, and the vast body of evidence tells us that they are still with us today in the form of birds, who are their direct descendants.

But today's entry involves just one family of many--Pachycephalosauridae: 'thick headed lizards', a group of animals native to the late Cretaceous (roughly 70-65 million years ago), the most famous of which was Pachycephalosaurus wyomingensis.


Pachycephalosaurus, whose remains have primarily been excavated from the badlands of the northern United States (right in my area--Montana and Wyoming specifically) was a primarily omnivorous animal whose most striking characteristic was a large dome or crest on the top of its head.

Though popular lore has dictated these creatures as using this display for head to head combat, a detailed analysis by Ken Carpenter done in 1997 suggests that these creatures would use their heads as both sexual display items and flank butting tools, in which they would pace around each other and charge the other's side to inflict non-lethal pain as a show of dominance.

Something like this, but much less Lion King-esque--

Among the data cited, Ken pointed out that by the shape of their spine, a direct head to head collision would bend the spinal column to the point that it would be highly likely for the spinal chord to be injured or even completely snapped, due to the 'S-Shaped' nature of the spinal column.

Additionally the surface area of their skull is poorly designed for direct impacts--the only contact point that would not result in a glancing blow is very small relative to the rest of the size of the skull.


This is in direct contrast to the massive surface area created by the curving horns of both mountain goats and bighorn sheep (both of whom engage in head butting behaviors) as seen here:



Note the drastic room for error in the angle of collision amongst the goats, something Pachycephalosaurus just did not have.

Hope you all got something both informational and enjoyable out of this!

Stay tuned next week.

Originally posted to Username4242 on Wed May 20, 2009 at 01:35 PM PDT.

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Comment Preferences

  •  I added the 'teaching' tag (4+ / 0-)

    so this diary will be in Daily Kos University which opens each Saturday at 9 AM Eastern, but stays open all week.

    No fees, no tests, no grades ... just learning

    If you  continue this series, could you add the 'teaching' tag?  thanks

    Dinos are cool.

  •  Awesome (3+ / 0-)
    Recommended by:
    northsylvania, radarlady, Curiosity

    They also had micropachycephalosauruses, which I love, because that's the longest dino name I know.

    "If I want to hear what I already know, I'll read the Huffington Post." --- Alec Baldwin as Jack Donaghy, "30 Rock"

    by droogie6655321 on Wed May 20, 2009 at 01:42:13 PM PDT

  •  My 10 y/o will love this. n/t (2+ / 0-)
    Recommended by:
    radarlady, Curiosity

    Oh, there you are, Perry. -Phineas -SLB-

    by boran2 on Wed May 20, 2009 at 01:42:51 PM PDT

    •  When it comes to dinosaurs... (0+ / 0-)

      We're ALL ten-year-olds.

      Great, informative diary, to which I will add one entirely trivial comment. When I clicked on it, I saw that first image, and a LOLcat-type caption immediately sprang to mind:

      Human: "Hi, there!"

      Pachycephalasaurus: "Oh, lunch!"

      Thankfully, this one's an omnivore, so it doesn't make my thought entirely meaningless.

      Radarlady, who still has the battery-powered T. Rex and Triceratops she got as a kid.

  •  I apparently retained something from childhood... (3+ / 0-)
    Recommended by:
    northsylvania, radarlady, Curiosity

    since I knew exactly which dinosaur it was by the name before opening the diary.

    Nice idea!

  •  My 6 y/o Will Too, And Pachy (4+ / 0-)

    As she refers to him (them) is one of her favorites. She likes to chase her Dad around pretending to be one and head butting him in the "flank" too.

    She's a raptor girl at heart, tho.

    Thanks for the diary!

    "I'll tell you, if there's anything worse than dealing with a staunch woman. S.T.A.U.N.C.H. There's nothing worse, I'm telling 'ya!". Little Edie

    by vintage dem on Wed May 20, 2009 at 01:52:26 PM PDT

  •  Love the video.... (2+ / 0-)
    Recommended by:
    northsylvania, radarlady

    almost comical.  typical cat wanting to play with its quarry but the quarry decides to put up a fight... thanks for the post.

  •  Add a pronunciation guide please. (1+ / 0-)
    Recommended by:

    Or even better an audio clip. My little one thinks I am omniscient and struggling with saying these names is going to tip her off that I just might not know everything.

    Blackwater is changing its name to Xe.

    by Toon on Wed May 20, 2009 at 02:14:45 PM PDT

  •  You kick ass too! (1+ / 0-)
    Recommended by:

    As a never really grew up out of it dinosaur fan I have to say thank you for this new series.

    That passed by; this can, too. - Deor

    by stevie avebury on Wed May 20, 2009 at 02:27:41 PM PDT

  •  I want to ride ... (1+ / 0-)
    Recommended by:

    ... a mammoth at Pleistocene Park.

    It's just not the same around here without the mega-fauna.

  •  I saw a TV doc recently about this dino (2+ / 0-)
    Recommended by:
    northsylvania, radarlady

    I understand how dino experts have to the "reverse engineer" dinosaurs based on what we understand about modern animals. But there's two major limitationswith that:

    1. We don't quite understand the physiology and behavior of many modern animals. Things like how seas turtles navigate the open seas or how monarch butterflies know where to go during migration even when they're blown way off course are big mysteries. So there could be similarities between modern animals and dinosaurs that we have yet to figure out due to what we don't know about modern animals.
    1. There may be factors of the dinosaurs' environment and life patterns unique to them and so we have no way of knowing so far, and may never know. If there are a physiological adaptation to these unknown variable, we may never figure them out.

    The weird debate about the Pachycephalosaurus skull is an example of the problem of our ignorance, and perhaps lack of imagination, when it comes to this reverse engineering. There's often this bias among dino experts that sides with the most violent theory: T Rex was a dominant predator, and the Pachycephalosaurus was a headbutter, for example.

    With Pachycephalosaurus, the headbutting theory seems all but disproved, although some experts are really fond of it still. Don't ask me why. Anyone with any experience with fighting and combat can tell that skull wasn't designed for full contact.

    It's believed the Pachycephalosaurus was an omnivore, and like modern omnivores, we can suspect it relied heavily on seasonal availability of food sources. I don't know what research has been done in regards to its olfactory capacity (they can figure out quite a bit from the brain and sinus cavities), but I was kicking around the idea that maybe this bulbous skull formation aiding the Pachycephalosaurus is getting around its environment, season by season, to find seasonal food sources. Like how a hammerhead shark's odd head shape helps it sense changes in ocean depth and the ocean floor below it, perhaps the Pachycephalosaurus' skull helped it sense changes in altitude and barometric pressure, to determine location and seasonal indicators like storm fronts.

    A similar theory has been kicked around with elephants, which has very sophisticated navigational skills and too possess a rather unique skull, one that's also capable to producing subsonic sounds. It's likewise possible that the Pachycephalosaurus could produce an unique range of sounds with this peculiar skull formation, which aided in socializing like with elephants. However, I am rather partial to the idea that the oddity of Pachycephalosaurus' skull is primarily for navigating in its environment and finding food. That's the most basic reason for any physical trait, yes? Things like communication and even sexual display may have evolved as secondary functions.

    Anyhow, that's just my theory. I haven't heard an real bono fide dino expert throw the altitude and barometric pressure theory out so far, so I thought I'd share it.

    -8.50, -7.64 "In the depth of winter, I finally learned that there was within me an invincible summer." - Camus

    by croyal on Wed May 20, 2009 at 05:17:40 PM PDT

    •  I could probably look into that for you. (2+ / 0-)
      Recommended by:
      northsylvania, radarlady

      The university I hope to be working with this fall uses CT scans to look at the inside of fossil skulls on collection, and I know they have a couple Pachycephalosaurs.

      I know a lot of research has been done on dinosaurian low frequency perception, but I'm not entirely sure if there have been any extensive studies on skull design and its relation to it (some research was done on the unique horn-like structure of Parasaurolophus and the possibility of a function for scent amplification, though the dominant theory these days is that it was primarily utilized as a low frequency call generator).

      Also, you may be interested in this--

      Mentions the skull structure of both elephants and cassowary birds and their functionality as low frequency call amplifiers, and the possibility of various dinosaurs utilizing something similar.

  •  My kid could spell pachycephalosaurus (1+ / 0-)
    Recommended by:
    radarlady first grade, at age 7.  

    Not that I'm bragging or anything :)

    Healthy Minds, Healthy Bodies, discussing outdoor adventures Tuesdays at 5 PM PDT

    by indigoblueskies on Wed May 20, 2009 at 08:36:48 PM PDT

  •  Awesome! (2+ / 0-)
    Recommended by:
    radarlady, Curiosity

    Things so much for sharing this, I love dinos.  Keep in up-I can't wait to see the next one you see fit to inform us about (a therapod perhaps???).

    God chose to put me in a red state because this is where the fight is.

    by ARDem on Wed May 20, 2009 at 08:52:11 PM PDT

  •  My 55 yo will love this, too. (3+ / 0-)
    Recommended by:
    northsylvania, radarlady, Curiosity

    Er, wait...that's me!

    Thanks for this.  Didn't know your diaries were a series until the rescue tonight.  I'm subscribing to your diaries so I can read the all.

    Thanks again!!!

    And now, purely for its comedic effect: Palin/Jindal 2012!

    by WSComn on Wed May 20, 2009 at 09:34:31 PM PDT

    •  They're wonderful. (2+ / 0-)
      Recommended by:
      radarlady, WSComn

      One of my first academic books on the subject was given to me by a paleontologist when I was about 8, and that section is still the first part I hit when going to the local museum. If you ever go to London, be sure to check out the collection at the Natural History Museum. They have some things that are unique to them. While looking for a picture of the enormous set of forelimbs from some weird predator (which I couldn't find) I found this interesting site with quick access to all kinds of dinosaur information. It links to Wikipedia articles with more depth.
      Thanks for this diary. Current information on theory is welcome, and hard to come by if you're not in the field.

      If nothing is very different from you, what is a little different from you is very different from you. Ursula K. Le Guin

      by northsylvania on Thu May 21, 2009 at 12:54:57 AM PDT

      [ Parent ]

  •  Harry Reid's patron dino for the week (3+ / 0-)
    Recommended by:
    radarlady, Username4242, Curiosity

    Based on Reid's statement on closing Guantanamo Bay, this is the right dino for Harry.  A bone headed ornithischian dinosaur for a bone headed politician.

    "If another country builds a better car, we buy it. If they make a better wine, we drink it. If they have better healthcare . . . what's our problem? "

    by mbayrob on Wed May 20, 2009 at 09:37:13 PM PDT

  •  Do you take requests? (2+ / 0-)
    Recommended by:
    northsylvania, radarlady

    Because I have 2 -
    Nanotyrannus (although I know the jury is out as to whether that is an actual species or not)

    BTW, given your first comment, about this being your field, am I correct in assuming your are either a palentologist, or in the field?  

    If so, would you be able to answer a question, in relation to some contemporaries of the non-avians - specifically, the Pterasaurs?  Specifically, do we have a better understanding of both the transition to flight, and also their relation to dinosaurs (I know Bob Baker at one time promoted the idea that they were closer related, but I know that was many years ago - wondering what the latest is)

  •  Thanks for starting this (0+ / 0-)

    fascinating and informative series and h/t to plf515 for including it in DKos U.

    Dinosaurs, as our friend from Colorado would say, are the shiznit.

    "Obama is just too smart to be stupid." --NYmind

    by Dragon5616 on Sat May 23, 2009 at 06:44:43 AM PDT

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