Palaeos		Paragastropoda
Mollusca		Paragastropoda

Paragastropoda

CONCHIFERA
`==Helcionelloida
   `--+--PARAGASTROPODA
      |  |--Pelagiellida
      |  `--Mimospirida
      |     |--Onychochilidae  
      |     `--+--Cliospiridae  
      |        `-?Omphallocirridae  
      `--+--Bellerophontoidea (torted)
         `--GASTROPODA (crown group) 

Drawing of the apical, apertural and basal view of Pelagiella atlantoides (Paragastropoda: Orthostrophina: Pelagielloidea: Pelagiellidae) From Matthew G.F. 1895. The Protolenus fauna. Transactions of the New York Academy of Sciences 14: 101-153. Pelagiella on the page 131. Plate VI., figure 6 a-c. Cropped, rotated and retouched by User:Snek01. via Wikipedia, Public domain.

The Paragastropods are an enigmatic assemblage of early paleozoic molluscs, known from their gastropod-like coiled shells. There is no guarantee they are a monophyletic assemblage. Some or all of them may be Helcionelloids, Gastropods, or even some other group entirely. With little to go one either than hard shells and muscle scars, ear;y molluscan phylogeny is a highly problematic affair at best. For now we have followed Linsley and Kier in placing these animals ina distinct, and possibly paraphyletic, class of untorted, stem-group gastropods, the Paragastropods MAK120617