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Atlanta helicinoidea Gray, 1850

This is the only species of Atlanta with eye type c.



Atlanta depressa Souleyet, 1852

Atlanta helicinoides Souleyet, 1852

  • The spire is flattened with 4½ to 4¾ whorls and is heavily ornamented with multiple continuous spiral ridges. This can make it difficult to identify the whorls, particularly the second whorl which is often narrow.

  • The keel is low and undulating.

  • The spire may be purple or tan-brown or red-brown. Juveniles are often tan-brown.

  • The adult shell is small, reaching only 2mm.

  • Eye type c, operculum type c, radula type I.

  • Two forms of this species have been identified from morphology, CO1 sequences and distributions.


Similar species: 



Further Reading:


Frontier, S., 1966. Notes morphologiques sur les Atlanta récoltées dans le plancton de Nosy Bé (Madagascar). Cahiers ORSTOM Oceanographie 4, 131–139.


Seapy, R.R., 1990. The pelagic family Atlantidae (Gastropoda: Heteropoda) from Hawaiian waters: a faunistic survey. Malacologia 32, 107–130.


Seapy, R.R. 2011. Atlantidae. In: Tree of life web project. Available at accessed 1 April 2017.


Seapy, R.R., Lalli, C.M., Wells, F., 2003. Heteropoda from Western Australian waters., in: The Marine Flora and Fauna of Dampier, Western Australia. Western Australian Museum, Perth, pp. 513–546.


Van der Spoel, S., 1976. Pseudothecosomata. Gymnosomata and Heteropoda. Bohn, Scheltema & Holkema, Utrecht.


Van der Spoel, S., 1972. Notes on the identification and speciation of heteropoda (Gastropoda). Zoologische mededelingen 47, 545–560.


Wall-Palmer, D., Burridge, A.K., Goetze, E., Stokvis, F., Janssen, A.W., Mekkes, L., Moreno-Alcántara, M., Bednaršek, N., Schiøtte, T., Vinther Sørensen, M., Smart, C.W., Peijnenburg, K.T.C.A. Biogeography and genetic diversity of the atlantid heteropods. Progress in Oceanography, 160:1–25. doi: 10.1016/j.pocean.2017.11.004

Wall-Palmer, D., Metcalfe, B., Leng, M.J., Sloane, H.J., Ganssen, G., Vinayachandran, P.N., Smart, C.W. Vertical distribution and diurnal migration of atlantid heteropods. Marine Ecology Progress Series, 587: 1–15. doi: 10.3354/meps12464.

Wall-Palmer, D., Smart, C.W., Kirby, R., Hart, M.B., Peijnenburg, K.T.C.A., Janssen, A. 2016. A review of the ecology, palaeontology and distribution of atlantid heteropods (Caenogastropoda: Pterotracheoidea: Atlantidae). Journal of Molluscan Studies, 1-14.


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