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Re: feathered ornithopods?




"Tracy L. Ford" wrote:
>>  [Cryoturbation]
> 
> I was talking to someone about this recently and he said that this geologic
> evidance may be due to some other kind of geology. I'm waiting to hear from
> him again on this.

Okay. On the one hand we have unpublished hear-say by one person. On the
other, we have several published papers by experts in geology and
permafrost conditions. Until the alternative theory is published, and
peer-reviewed, I'm going with the odds.

>> [Iceberg/glacial dropstones]

> Whats the published papers on this? I'd be interested to read them.

I'll have to look this up. I believe it was mentioned in "Wildlife of
Gondwana". I'll get back to you with any specific references.

> Ok, but are all alpine forest's have a snow period? I haven't a clue if they
> have to have one or not.

The prevailing theory about the Koonwarra fish beds is that the
creatures died when a shallow section of the lake froze over, either
freezing the animals to death or, more likely, cutting off their oxygen
supply.

> 
> See http://www.alphalink.com.au/~dannj/ecenvir.htm<<
> 
> Nice link. So can all those plants you listed live in a climate that freezes
> over? Do any of them do that today?

As you yourself pointed out, we shouldn't impose our modern predjudices
onto Mesozoic ecosystems. The on-going pollen and wood analysis of Doris
Seegers Villiers indicates that although the numbers of pollen and
spores found in the Strzelecki siltstones and mudstones are high, the
diversity of species is low. Perhaps this indicates a rather specialised
floral ecosystem. Also, ferns and other low-growing plants (like club
mosses) appear to have dominated. We know that trees grew in the area
(petrified trunks, fossilised leaves), however they may not have formed
a continuous forest canopy.

> Fine, let me 'try' again. What about the Antarctic Cretaceous dinosaurs?
> Hadrosaurs and ankylosaurs? Where they covered in integument to survive the
> supposed frosty winters? No way IMHO. What about the Freamouv Formation?
> Would that have had a 'frosty' time? Procolophonids, labyrinthodontis,
> prolacertaforms..

Australia was some-what of a peninsular, and cut up into smaller islands
at times during the EK. The rest of Antarctica seems to have been more
intact, perhaps allowing large animals (like hadrosaurs) to migrate
seasonally (as has been suggested for the Arctic dinosaur faunae).
Ankylosaur scutes are also found in Victoria, so perhaps these animals
could cope with the colder conditions (perhaps with fat reserves, since
they were already adapted to carrying a heavy load).

>> [Plesiosaur breeding practices]
> 
> Well, this is a theory. Pretty good one...So, what's the paper/s on this?
> Just so I'm up to date on this.

There was a paper recently referenced here on the list, about an
Antarctic sub-adult plesiosaur. 

Fostowicz-Frelik, £. and Ga?dzicki, A. 2001. Anatomy and histology of
plesiosaur bones from the Late Cretaceous of Seymour Island, Antarctic
Peninsula. In: A. Ga?dzicki (ed.), Palaeontological Results of the
Polish
Antarctic Expeditions. Part III. _Palaeontologia Polonica_ 60: 7?32.

I don't know if anything seminal has been published on the South
Australian opalised marine reptiles, but you can read about them at the
S.A.Museum's website:

http://www.samuseum.sa.gov.au/plesiosaur/screen.htm

> >>Hypsilophodontids may have also chosen the polar areas to breed in.<<
> 
> Don't know that for sure. Have there been any eggs/eggshells found yet?

No, but they have found embryonic hypsie bones at Flat Rocks (115 MYA).
So they definitely bred their. The remains of baby hypsies have also
been found in the opal fields of South Australia. See:

http://www.cmnh.org/dinoarch/2002Feb/msg00687.html

The link in the message may not work, but if you like I can forward the
original text.

> 
> >>There are lots of juvenile remains found in Victoria and South
> Australia. One specimen, probably a Leaellynasaura, was found with an
> advanced osteomyelitic infection of the tibia.<<
> 
> I have this specimen listed as Hypsilophodonid gen sp indet. If you know
> otherwise I'd like to know and I'll change that in my lists.

In "Dinos of Darkness" it mentiones that it MAY be another
Leaellynasaura. But then again, in 1993 it was mentioned in "Wildlife of
Gondwana" that it could be an Atlascopcosaurus, and Pat Vickers-Rich
once mentioned to me in the mid-1990s that it might eventually get its
own name. So don't change your listing just yet...

>> This suggests to me that predators were
> pretty thin on the ground, perhaps why the hypsies chose this area to
> breed in (like a modern version of Arctic geese).<<
> 
> Don't know that for sure. Theropods are outnumbered what 10 to 1. Different
> than other areas...

Either do I. Rampant speculation on my part.

-- 
________________________________________________________________

Dann Pigdon                   Australian Dinosaurs:
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://www.alphalink.com.au/~dannj/
________________________________________________________________