Orthogastropoda

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Orthogastropoda
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Orthogastropoda
a red shelled marine snail with a white and black spotted foot
Conus geographicus (a marine snail)

Orthogastropoda was a major taxonomic grouping of snails and slugs, an extremely large subclass within the huge class Gastropoda according to the older taxonomy of the Gastropoda (Ponder & Lindberg, 1997).

This taxon is no longer used according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005.

Ponder and Lindberg (1997) in the book The Southern Synthesis, showed the Orthogastropoda as one of two subclasses of the Gastropoda, the other subclass being a very much smaller group called the Eogastropoda, which contained only 5 families of true limpets.

This subclass, Orthogastropoda, which one perhaps could call the true snails, was defined most concisely as all gastropods which were not members of Patellogastropoda, the true limpets.

The Orthogastropoda appeared to form a clade which was supported by unambiguous synapomorphies. These synapomorphies (a series of characteristics that appear in its members but not in the other forms it diverged from) were the identifying characteristics of the clade.

Some of the characteristics were:

  • eyes with a vitreous body on eyestalks.
  • paired jaws, with their position free from the buccal mass
  • a single kidney on the right side of pericardium
  • a flexoglossate radula (with a flexible radular membrane). The radula is the snail's tongue, used as a rasping tool.
  • unpaired osphradium (olfactory organ).
  • lateral ciliated zones of osphradium
  • a single left hypobranchial gland (on organ at gill, which releases secretions, such as the reddish dye Tyrian purple).
  • an unpaired ctenidium (a comblike respiratory structure in certain mollusks)

Taxonomy

The following is based on the somewhat out-dated taxonomy of the Gastropoda (Ponder & Lindberg, 1997). For the most up-to-date system of gastropod taxonomy, please see Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005).

Superorder

Cocculiniformia
Haszprunar, 1987

  • Superfamily
    Dall
    , 1882
  • Superfamily
    Dall
    , 1882 (deep sea limpets)

Superorder incertae sedis (Hot Vent Taxa)

  • Order Neomphaloida Sitnikova & Starobogatov, 1983
    • Superfamily Neomphaloidea McLean, 1981 (hydrothermal vent limpets)
    • Superfamily Peltospiroidea McLean, 1989

Superorder Vetigastropoda Salvini-Plawen, 1989 (limpets)

  • Superfamily
    Fissurelloidea
    Flemming, 1822 (keyhole limpets)
  • Superfamily
    Rafinesque
    , 1815 (abalones)
  • Superfamily Lepetodriloidea McLean, 1988 (hydrothermal vent limpets)
  • Superfamily Pleurotomarioidea Swainson, 1840 (slit shells)
  • Superfamily Seguenzioidea Verrill, 1884
  • Superfamily
    Rafinesque
    , 1815 (top shells)

Superorder Neritaemorphi Koken, 1896

  • Order
    Neritopsina
    Cox & Knight, 1960
    • Superfamily
      Lamarck
      , 1809

Superorder Caenogastropoda Cox, 1960

Superorder Heterobranchia J.E. Gray, 1840

References

  1. ^ "Order Sorbeoconcha Ponder and Lindberg 1997 (snail)". Fossilworks.
  2. ^ "WoRMS taxon details". World Register of Marine Species.