TaningiaDanae;140466 said:how do we know that these forms aren't just deleterious mutations of existing ammonite species, rather than normal representatives of distinct species?
Hajar;140463 said:What do you think mode of life was for this Polyptychoceras?
I quite like the repeated toppling model here as a way of making a shell with this shape: http://www.ebel-k.de/Ammoniten/Lifestyle1/Heteromorphs/heteromorphs.html,
but reconstructions elsewhere seem to always show a gently inclined to the horizontal position (e.g. http://www.tonmo.com/community/index.php?threads/3656/).
monty;140490 said:I thought we knew the orientation of most ammonites from the lines showing the position of cameral fluid... is that the source of the orientation for these? Of course, that may only reflect the orientation shortly before death.
Are there good examples of the intermediate growth phases for these?