I'm hoping someone who knows a lot about the evolution of the Nautilus will help me with this question. So as far as I'm aware, the ancestral number for all cephalopod limbs is ten and nautiloids had gained more (up to ninety). The thing I'm wondering is how and why, mainly the how part. Did the nautilus gain more limbs by splitting old ones or growing new ones directly from the head? I feel as if it's the latter because of this image below, during the nautilus's embryotic development it grows it's tentacles all at the same time from the foot. How do you guys think the nautilus gained so many limbs? Please let me know!