The mid-Ordovician saw the 1st cephalopods with septa sturdy adequate to manage While using the pressures linked to deeper drinking water, and could inhabit depths larger than 100200 m.[139] The way more of shell coiling would demonstrate to be important to the future results in the lineages; endogastric coiling would only allow huge sizing for being attained which has a straight shell, While exogastric coiling in the beginning fairly