The mid-Ordovician noticed the very first cephalopods with septa powerful enough to manage Along with the pressures linked to deeper h2o, and will inhabit depths higher than a hundred200 m.[139] The course of shell coiling would demonstrate to become very important to the long run achievement of your lineages; endogastric here coiling would only allow big sizing to get attained having a straight shell, Whilst exogastric coiling at first alternatively