View Full Version : Have we all been wrong all these years?


Phil
Mar 19th, 2006, 10:56am
Have a look at this bizarre reconstruction (http://www.ebel-k.de/Ammoniten/ammoniten.html) of ammonites at the top of the page. Ammonites depicted as marine snails?

:bugout: :goofysca: :shock:

cthulhu77
Mar 19th, 2006, 11:40am
You? Wrong? Never ! Wish I could read german better...I only got about half of that text.

chrono_war01
Mar 19th, 2006, 11:44am
...If we're wrong, then at least we it's not the first time assumed something wrongly...but I seriously doubt that ammonites with large and heavy shells that are upright would most certinaly topple, no?

Architeuthoceras
Mar 19th, 2006, 02:37pm
Well, since I flunked algebra, there is no way I could proove this theory wrong or right. Physicists got involved in the T. rex scavenger/predator debate too. :wink:

I need more than math to show me it dont float. 8-)

Nancy
Mar 19th, 2006, 02:45pm
Actually, I do read German fairly well - the author is using that picture to illustrate the old theories of ammonites. The article talks about them floating and he even uses the word "swimming".

Now, I'm not up on my ammonites since I have so much to do on the Ceph Care forums - what is the current theory?

Nancy

cuttlegirl
Mar 19th, 2006, 02:56pm
I found this article by Neale Monks and Jeremy Young
Body Position and the Functional Morphology of Cretaceous Heteromorph Ammonites
http://palaeo-electronica.org/1998_1/toc.htm

ob
Mar 19th, 2006, 04:02pm
There's nothing wrong with retro-extrapolating from Nautilus, whilst assuming some varieties of ammonites where shuffling along the bottom. Octopus sp. do a lot of that also, if I might say so :grin:

PS: Some of this is in English (http://www.ebel-k.de/Ammoniten/Ammovortrag1/ammovortrag1.html)

Tintenfisch
Mar 19th, 2006, 04:13pm
Great first paragraph. :roll:

'Ammoniten konnten ganz sicher nicht schwimmen. Das lässt sich mit den von Archimedes schon vor 2000 Jahren gefundenen Regeln der Hydrostatik sowie der Hebelge- setze ganz eindeutig nachweisen. Sie waren ausnahmslos Bodenbewohner und mussten sich somit kriechend fort- bewegen, auch wenn es mancher Thomas nicht so recht glauben mag - not my problem.'

'Ammonites were certainly unable to swim. This is proven, without a doubt, by the rules of hydrostatics (discovered by Archimedes more than 2000 years ago), as well as the principle of the lever (?). They were, without exception, benthic ('floor-residents') and therefore moved by crawling; if some people choose not to believe this, not my problem.'

ob
Mar 19th, 2006, 04:15pm
The use of "thomas" for unbeliever is striking :grin:

Tintenfisch
Mar 19th, 2006, 06:12pm
Yeah, decided not to tackle the finer nuances of translating that one. :wink:

Architeuthoceras
Mar 20th, 2006, 01:00pm
Some very persuasive arguments (no x+y stuff to confuse me) are brought up on the hydrostatics (http://www.ebel-k.de/Ammoniten/Hydrostatics/hydrostatics.html) page. One question though, Spirula is used as an example for vertical shell (or body) orientation, why is it not crawling along the bottom like a snail? :hmm:

Should I really question my belief in Santa Claus?

djbirdnerd
Feb 10th, 2008, 12:52pm
I must say everybody is entitled to their own opinion, but i strongly disagree with this German guy Eble. He is by the way a physicist and not a paleontologist, who also claims that archaeopteryx was a underwater swimmer. He states that all ammonoids (heteromorph or not) were benthonic (and by this he mains really benthonic on the bottom and not demersal like some fish). He came to this by making false assumptions on ammonoid growth and his own calculations of negative buoyancy of ammonoids, which were proven wrong by all other studies, which all gave values within the margin of error of neutral buoyancy. If would by the way be very hard to live on the seafloor with a negatively buoyant shell (must of been drag carrying that around). It think it is ok to assume that the hydrostatic apparatus was working, because they all (even the weirdest heteromorphs like Nipponites) posses (and did not lose) their siphuncle. So per definition they would be somewhere in the water column from swimmers to planktonic floaters or vertical migrants. Some of them could have feeded demersally on the bottom (some orthoconic forms without adapical ballast) or potentially gyroconic forms, while other must have unmistakenly fed in the water column with a stabile upward pointed aperture (assuming soft parts filled the entire body chambers => see some of the discussions from Neal Monks)...

cthulhu77
Feb 10th, 2008, 05:46pm
I think they were whitegold wielders.

Yeah, a little bit of unrealistic explanation going on here...sort of like scientists who state that bumblebees can not fly.

Ummm....ow.

bigGdelta
Feb 14th, 2008, 07:43am
I think they were whitegold wielders.

Yeah, a little bit of unrealistic explanation going on here...sort of like scientists who state that bumblebees can not fly.

Ummm....ow.

Thomas Covenent as ammonite?

Sordes
Feb 22nd, 2008, 01:40pm
Cthulhu77: Thing with the bumblebees turned out to be false, there are no physical problems to prove that they can fly...just BTW