Editing Tusk shell (section)

=== Fossil record ===
[[File:05898 Grand Canyon Mollusca Fossils (4739033749).jpg|thumb|[[Internal mold]] of a fossil scaphopod, [[Kaibab Formation]] ([[Grand Canyon]])]]
There is a good fossil record of scaphopods from the [[Mississippian (geology)|Mississippian]] onwards,<ref name="Yochelson20072">{{cite journal|author=Ellis L. Yochelson|author2=Royal H. Mapes|author3=Doris Heidelberger|year=2007|title=An enigmatic molluscan fossil from the Devonian of Germany: scaphopod or cephalopod?|journal=Paläontologische Zeitschrift|volume=81|issue=2|pages=118–122|doi=10.1007/BF02988386|bibcode=2007PalZ...81..118Y |s2cid=85124687}}</ref> making them the youngest molluscan class.

The Ordovician ''[[Rhytiodentalium]] kentuckyensis'' has been interpreted as an early antecedent of the scaphopods, implying an evolutionary succession from [[ribeirioid]] [[rostroconch]] molluscs such as ''[[Pinnocaris]]''.  However, a competing hypothesis suggests a Devonian/Carboniferous origin from a non-mineralized ancestor, or from a more derived, Devonian, [[conocardioid]] rostroconch.<ref name="Peel20042">{{Cite journal|author=Peel, J.S.|year=2004|title=''Pinnocaris'' and the origin of scaphopods.|journal=Acta Palaeontologica Polonica|volume=49|issue=4|pages=543–550}}</ref>