[2] The oldest fossils are known from the Cenomanian aged Burmese amber.

[3] Various species in this family occur in estuarine habitats, in salt marshes and in freshwater.

The shell is small to medium large, more or less egg-conelike shaped.

[2] Species in this family are characterized by rudimentary cephalic tentacles, a trunklike snout, a foot with a groove and rudimentary to absent ctenidium (a comb-like respiratory apparatus).

[4] The following three subfamilies were recognized in the taxonomy of Bouchet & Rocroi (2005): Genera in the family Assimineidae include:[5][6][7] Genus † Laternoides W. Yu & Y.-H. Xi, 1977 subfamily Assimineinae subfamily Ekadantinae subfamily Omphalotropidinae Thiele, 1927 (synonym: Garrettiinae Kobelt, 1906) This article incorporates public domain text from the reference.