Phil;43583 said:ammonite with striped pigment bands still showing. I'll see if I can scan it tonight for you. In truth, no-one really knows how they were decorated.
As for depictions of nautiloids with reddish-brown striped patterns I'm sure they are just extrapolated from Nautilus.
Phil;43589 said:The lower image is of the Miocene nautiloid Aturia and one can make out a trace of patterning very similar to Nautilus. With the ammonite the patterning resembles a snail rather than the familiar Nautilus patternation.
Thanks!
Allonautilus;81819 said:Some sources say that aptychi are elaborate lids, while others say "jaw apparatus". By that word, are they actually parts of ammonite's beak, or even analogous to coleoid beaks?
monty;114313 said:to TONMO
I thought I remembered that part of the lack of patterns was that the actual shell material is rarely preserved, but I know that occasionally even proteins in the shell have survived, which doesn't seem consistent with a loss of the shell patterning... hmmm...
Architeuthoceras;131941 said:The PaleoNet pages Gallery has a new exhibition with some drawings of nautiloids, see: Back to the Past, by Enrico Bonino. Its on the home page, I cant link to the actual gallery.
Architeuthoceras;42040 said:Only one, Pravitoceras, could be fixed, and I dont have a clue as how to fix it The early whorls are coiled normally so the venter would be towards the outside (or the convex side) of the shell. At maturity it coils the opposite direction so the venter would now be on the inside (or the concave side). Most ammonites (according to a Nautilus model) are oriented with the funnel ventral, and the eyes dorsal (? is this the same with squid & octopuses), just the opposite of the reconstruction, unless the animal twisted 180 degrees in it's shell. Of course if you drew it that way it would look upside down. Anything that grew a weird shell like that was bound to be peculiar to start with.