The Caenogastropoda exhibit torsion, and thus are included in what was previously called the Streptoneura (meaning twisted nerves), also known as Prosobranchia (meaning gills forward). Specifically, they are characterized by having only a single auricle in the heart and a single pair of gill leaflets, and are equivalent to the Monotocardia or Pectinibranchia of older authors.
The taxon Caenogastropoda was first established by Leslie Reginald Cox in 1960 as a superorder[5] but now sometimes it is retained as a clade. Based on optimal phylogenetic analysis, it is deemed monophyletic.[6] This Caenogastropoda combines the older taxa Mesogastropoda and Stenoglossa from the classification by Johannes Thiele[7] and is equivalent to the revised Monotocardia as defined by Mörch in 1865.
Caenogastropoda can be divided into two major groups, based on the anatomy of the radula:
Taenioglossa (from taenio meaning band), equivalent to the older Mesogastropoda, with typically seven teeth in each radular row.
Ponder & Lindberg, 1997 and others since (e.g. Vega et al., 2006;[8] Harzhauser, 2004;[9] and Pina, 2002.[10]) show Caenogastropoda as a superorder, following the sense of Cox, 1960. More recently Bouchet & Rocroi, 2005 revised Caenogastropoda as a clade.
Sorbeoconcha should include [Cerithioidea + Campaniloidea + all Hypsogastropoda (i.e. the remaining Caenogastropoda)], see definition in Ponder & Lindberg, 1997: 225, not only [Cerithioidea + Campaniloidea] as suggested by the indent pattern in Bouchet & Rocroi. Neotaenioglossa Haller, 1892 suggested in Ruud Bank's draft for Fauna Europaea is not retained because it would need severe emendation to remove Pyramidellids, Cerithioids, etc. included in its original definition, and therefore would be too far from Haller's concept if it were to fit the concept of Sorbeoconcha. Although cladistically sound, the taxon Sorbeoconcha is skipped in the classification scheme because (1) ten years after its publication, the name still sounds unfamiliar to most and (2) it is not very helpful in the classification because it includes the bulk of Caenogastropoda (only keeping out small stem groups Abyssochrysidae, Provannidae, and the architaenioglossate taxa). This is not final, opinions are welcome.[12]
^Ponder, W. F.; Colgan, D. J.; Healy, J.; Nützel, A.; Simone, L. R. L.; Strong, E. E. (2008). "Caenogastropoda". In Ponder, W. F.; Lindberg, D. L. (eds.). Phylogeny and Evolution of the Mollusca. Berkeley: U. California Press. pp. 331–383. hdl:10088/7547.
^ abCox L. R. (1960). In: Moore R. C. (ed.) Treatise on invertebrate paleontology. Part I., Mollusca 1, Gastropoda. The Geological Society of America, University of Kansas Press, Lawrence. xxiii + 351 pp., page 311.
^Aktipis, Stephanie W.; Giribet, Gonzalo (2010). "A phylogeny of Vetigastropoda and other "archaeogastropods": Re-organizing old gastropod clades". Invertebrate Biology. 129 (3): 220–240. doi:10.1111/j.1744-7410.2010.00198.x.
^F. J. Vega et al. 2006. El Espinal, a new plattenkalk facies locality from the Lower Cretaceous Sierra Madre Formation, Chiapas, southeastern Mexico. Revista Mexicana de Ciencias Geológicas 23(3):323-333
^Harzhauser M. (2004). "Oligocene gastropod faunas for the Eastern Mediterranean (Mesohellenic Trough/Greece and Esfahan-Sirjan Basin/Central Iran)". Courier Forschungsinstitut Senckenberg248: 93-181.
