Fig. 2

Comparisons in shell morphology between the oldest fossil heteropods and larval shells of extant members of the Atlantidae. a Juvenile Atlanta selvagensis collected live from the Atlantic Ocean in 2010, b Juvenile A. selvagensis, a recent fossil from Caribbean sediments, c–d The oldest potential heteropod, Coelodiscus minutus from the Early-Middle Jurassic (190.8–170.3 Ma). Specimens BSPG 2008 XXIX 42c and BSPG 2008 XXIX 56f, images from Teichert and Nützel [16], e–f Juvenile Oxygyrus inflatus collected live from the Atlantic Ocean in 2010, g–h The oldest potential Atlantidae, Belerophina minuta from the Early Cretaceous (~ 113–100.5 Ma). Bellerophina images courtesy of Steven Tracey [22]