Welcome Guest [Log In] [Register]






Shoot a firework rocket ~ Winners!
Make a forum zoo!

Welcome to The Round Table. We hope you enjoy your visit.


You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are some features you can't use. If you join our community, you'll be able to access member-only sections, and use many member-only features such as customizing your profile, sending personal messages, and voting in polls. Registration is simple, fast, and completely free.


Join our community!


If you're already a member please log in to your account to access all of our features:

Username:   Password:
Add Reply
Extinct Animal Questions
Topic Started: Nov 26 2013, 10:24 PM (193,405 Views)
Taurotragus
Member Avatar


To be truthful I didn't even think it was a Kaprosuchus at first. Thanks.
Offline Profile Quote Post Goto Top
 
Posted Image Guat
No Avatar


Would it be possible for alvarezsaurs to climb up onto the backs of sauropods to feed on parasites on the sauropod skin?
Offline Profile Quote Post Goto Top
 
Incinerox
Member Avatar
Āeksiot Zaldrīzoti

That's a pretty big climb for something with tiny arms and sprinters legs and feet.
Offline Profile Quote Post Goto Top
 
CyborgIguana
Member Avatar


I could potentially see them as doing that with a resting sauropod.
Offline Profile Quote Post Goto Top
 
Taurotragus
Member Avatar


Imagine if the sauropods got up while the little dinos were still on their backs. The Alvarezsaurs would be stranded on a walking island.
Edited by Taurotragus, Apr 6 2015, 12:43 PM.
Offline Profile Quote Post Goto Top
 
Acinonyx Jubatus
Member Avatar
I AM THE UNSHRINKWRAPPER!

How flexible were the back spines of creatures like Dimetrodon and Secodontosaurus?
Offline Profile Quote Post Goto Top
 
Incinerox
Member Avatar
Āeksiot Zaldrīzoti

Well, it seems that they were anatomically reinforced with some weird changes in cross section going along each neural spine.

Wikipedia
 
Near the vertebra body, the spine cross section is laterally compressed into a rectangular shape, and closer to the tip, it takes on a figure-eight shape as a groove runs along either side of the spine. The figure-eight shape is thought to reinforce the spine, preventing bending and fractures. A cross section of the spine of one specimen of Dimetrodon giganhomogenes is rectangular in shape but preserves figure-eight shaped rings close to its center, indicating that the shape of spines may change as individuals age.


I'd assume Secodontosaurus was the same, and maybe even a running thing in all sailed pelycosaurs. That'll take further research though.

What got me was this:

Wikipedia
 
The microscopic anatomy of each spine varies from base to tip, indicating where it was embedded in the muscles of the back and where it was exposed as part of a sail. The lower or proximal portion of the spine has a rough surface that would have served as an anchoring point for the epaxial muscles of the back, and also has a network of connective tissues called Sharpey's fibers that indicate it was embedded within the body. Higher up on the distal (outer) portion of the spine, the bone surface is smoother. The periosteum, a layer of tissue surrounding the bone, is covered in small grooves that presumably supported the blood vessels that vascularized the sail.


And this:

Quote:
 
The large groove that runs the length of the spine was once thought to be a channel for blood vessels, but since the bone does not contain vascular canals, the sail is not thought to have been as highly vascularized as once thought. Some specimens of Dimetrodon preserve deformed areas of the neural spines that appear to be healed-over fractures. The cortical bone that grew over these breaks is highly vascularized, suggesting that soft tissue must have been present on the sail to supply the site with blood vessels. Layered lamellar bone makes up most of the neural spine's cross-sectional area, and contains lines of arrested growth that can be used to determine the age of each individual at death. In many specimens the distal portions of spines bend sharply, indicating that the sail would have had an irregular profile in life. Their crookedness suggests that soft tissue may not have extended all the way to the tips of the spines, meaning that the sail's webbing may not have been as extensive as it is commonly imagined.


I'd really like to know if we've got skin impressions for Dimetrodon's SAIL.
Edited by Incinerox, Apr 6 2015, 01:34 PM.
Offline Profile Quote Post Goto Top
 
Furka
Member Avatar


Is the american lion still considered a subspecies of Panthera leo ?
Because I remember hearing a study proposed it to be closer to jaguars.
Offline Profile Quote Post Goto Top
 
Incinerox
Member Avatar
Āeksiot Zaldrīzoti

Closer. As of 2011, it was put somewhere between Jaguars and Eurasian Cave Lions.
Offline Profile Quote Post Goto Top
 
Brach™
Member Avatar
hi

Like it's not a lion or a Jaguar. It's hard to say for sure because Panthera is so diverse yet closely related which is why I'm neither comfortable with American lion or Giant Jaguar. At this point I've just started calling it by it's Latin name or Giant Panther.
Offline Profile Quote Post Goto Top
 
Incinerox
Member Avatar
Āeksiot Zaldrīzoti

I could totally roll with that. Giant American Panther it is.
Offline Profile Quote Post Goto Top
 
Paleop
Member Avatar
Paleopterix

are scientist still trying to make chickens turn into non avian dinosaur lookalikes?
Offline Profile Quote Post Goto Top
 
CyborgIguana
Member Avatar


I think Horner was the only guy who was ever serious about that, and it doesn't look like he's had any success since he first proposed the idea.
Offline Profile Quote Post Goto Top
 
Acanthophis
No Avatar


Avisaurus was raptorial?
Offline Profile Quote Post Goto Top
 
CyborgIguana
Member Avatar


Last I checked it was an insectivore.
Offline Profile Quote Post Goto Top
 
3 users reading this topic (3 Guests and 0 Anonymous)
ZetaBoards - Free Forum Hosting
Fully Featured & Customizable Free Forums
Learn More · Sign-up Now
Go to Next Page
« Previous Topic · Extinct Animals & Evolution · Next Topic »
Add Reply