Editing Tusk shell (section)

==Classification==
The group is composed of two subtaxa, the [[Dentaliida]] (which may be paraphyletic) and the monophyletic [[Gadilida]].<ref name=Steiner1992>{{Cite journal| doi = 10.1093/mollus/58.4.385| title = Phylogeny and Classification of Scaphopoda| year = 1992| last1 = Steiner | first1 = G. .| journal = Journal of Molluscan Studies| volume = 58| issue = 4| pages = 385–400 }}</ref>
The differences between the two orders is subtle and hinges on size and on details of the radula, shell, and foot. Specifically, the Dentaliids are the physically larger of the two families, and possess a shell that tapers uniformly from anterior (widest) to posterior (narrowest); they also have a foot which consists of one central and two lateral lobes and which bends into the shell when retracted.  The Gadilids, on the other hand, are much smaller, have a shell whose widest portion is slightly posterior to its aperture, and have a foot which is disk-like and fringed with tentacles which inverts into itself when retracted (in this state resembling a pucker rather than a disk).
[[File:Calliodentalium semitracheatum (MNHN-IM-2012-13993).jpeg|thumb|Shell of ''Calliodentalium semitracheatum'' <small>(Boissevain, 1906)</small> (specimen at MNHN, Paris)]]
According to the [[World Register of Marine Species]]:
* [[Dentaliida]] <small>da Costa, 1776</small>  
** family [[Anulidentaliidae]] <small>Chistikov, 1975</small> – 3 genera
** family [[Calliodentaliidae]] – 1 genus
** family [[Dentaliidae]] <small>Children, 1834</small> – 14 genera
** family [[Fustiariidae]] <small>Steiner, 1991</small> – 1 genus
** family [[Gadilinidae]] <small>Chistikov, 1975</small> – 3 genera
** family [[Laevidentaliidae]] <small>Palmer, 1974</small> – 1 genus
** family [[Omniglyptidae]] <small>Chistikov, 1975</small> – 1 genus
** family [[Rhabdidae]] <small>Chistikov, 1975</small> – 1 genus
* [[Gadilida]] <small>Starobogatov, 1974</small>
** sub-order [[Entalimorpha]] <small>Steiner, 1992</small>
*** family [[Entalinidae]] <small>Chistikov, 1979 </small> – 9 genera
** sub-order [[Gadilimorpha]] <small>Steiner, 1992</small>
*** family [[Gadilidae]] <small>Stoliczka, 1868</small> – 8 genera
*** family [[Pulsellidae]] <small>Scarabino in Boss, 1982</small> – 3 genera
*** family [[Wemersoniellidae]] <small>Scarabino, 1986</small> – 2 genera