The first fossil gastropods date from the early Cambrian, 570 million years ago (Ma) and were marine. Some of the 20,000 known fossil forms, such as some Turitella and Conus species have changed little in the last 50 million years. Since many members of the class have remained the same since the initial evolution of gastropods, a brief survey of many of the forms alive today is useful in exploring what gastropods were like in the past.
Figure 1: Conus Fossil and Recent Conus. The shell on the right is a fossil, while the Endemoconus seieboldii shell on the left was found recently near Japan. Despite the vast expanse of time and subsequent loss of some details in the fossil, these two shells are virtually identical.