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From: John D'Angelo <assuming.dinosaur@gmail.com>
Sent: Wednesday, July 3, 2019 3:58 PM To: Anthony Cc: RTravsky@uwyo.edu; dinosaur-l@usc.edu; Gregory Paul Subject: Re: [dinosaur] T. rex hunting Alamosaurus >Titanosaurs were not armored—at least, not in a way comparable to, for
example, ankylosaurs. I think next to nothing were *that* armored. :)
> Their osteoderms were clearly very sparse (I
don't think any titanosaur specimen has ever been found with more than around four osteoderms associated), so they did not provide the kind of full-body coverage "armor" implies. ...which sort of blows a hole in the idea of carnivores essentially grazing on the sides of sauropods - one would think they'd develop a defense against it.
> In some species, the osteoderms
were hollow, decreasing their protective value and suggesting that,
instead, the osteoderms may have acted as a kind of nutrient reservoir. It is possible that, in female titanosaurs, osteoderms served a role similar to medullary bone in other dinosaurs. Then there is, of course, the possibility that they were used for visual signaling. In some species, such as Ampelosaurus, the osteoderms supported prominent spikes and perhaps could be compared to the plates of stegosaurs. As a calcium reserve to draw upon for making the eggshells, yes? Turtles do that too. (i'm not disagreeing with you)
>Suffice to say, there is no evidence that titanosaur osteoderms
existed for defensive purposes, so it is perhaps misleading to
describe them as "armored." the title escapes me, but I used to read dinosaur books that described titanosaurs as "the armored sauropods"...so it may have been more a comparison than the descriptive I then assumed it to be.
> Some small titanosaurs, such as
Saltasaurus, did have dermal ossicles in addition to the large osteoderms, and perhaps these were used for a protective purpose, but in the majority of titanosaurs, there isn't really evidence for it. the aforementioned books refered to Saltasaurus as a typical titanosaur...ergo my presumption on the subject of armor. my apologies.
On Wed, Jul 3, 2019 at 10:38 AM Anthony <keenir@hotmail.com> wrote: > > well, that would certainly explain why Alamosaurus had armor...though leaves open the question of why armor wasn't more common among sauropods. > > ________________________________ > From: dinosaur-l-request@usc.edu <dinosaur-l-request@usc.edu> on behalf of Gregory Paul <gsp1954@aol.com> > Sent: Wednesday, July 3, 2019 12:08 PM > To: RTravsky@uwyo.edu; dinosaur-l@usc.edu > Subject: Re: [dinosaur] T. rex hunting Alamosaurus > > I proposed the possibility that large theropods dashed in and took off chunks of flesh in the 1998 Modern Geology formation volumes on the Morrison Formation. Especially the relatively modest sized allosaurs relative to the far larger sauropods. > > > -----Original Message----- > From: Richard W. Travsky <RTravsky@uwyo.edu> > To: DML <dinosaur-l@usc.edu> > Sent: Wed, Jul 3, 2019 1:12 am > Subject: RE: [dinosaur] T. rex hunting Alamosaurus > > Other scenarios: > > A kill is not necessarily needed, tearing off chunks not unlike a shark attack. > > Could a rex kick? Thinking of ostriches or emus and clawed feet. > > Ambush hunting? Though one would think that with the height of the head on a sauropod – any sauropod – an ambush might be hard to arrange. > > Given that long, stiff neck, just how agile would that Alamosaurus have to be to deal with an attack, fatal or not? (Giraffe comes to mind) > > > From: dinosaur-l-request@usc.edu [mailto:dinosaur-l-request@usc.edu] On Behalf Of Thomas Richard Holtz > > > What Mike says is true for adults. > > But given that most dinosaurs spent most of their life cycle as not-fully-grown, how to kill a younger Alamosaurus? Neck bites would be the quick way, particularly with the bone-crushing strength of a T. rex bite. Also, a disabling bite to the thigh or a massive bite on the abdomen might do the job. |