Seguenzioidea Explained

Seguenzioidea is a superfamily of minute to medium-sized sea snails, marine gastropod mollusks in the clade Vetigastropoda.^{[1] [2]}

Description

The distinctive characteristics of the shells of the Seguenzioidea are:

• the nacreous layer (a plesiomorphic character, i.e. a character state that a taxon is inferred to have been retained from its ancestors) This occurs also in the following families: Pleurotomariidae, Haliotidae, Turbinidae, Trochidae, and possibly in the Skeneidae.
• the protoconch has a trochoid shape.
• usually with one or more labral sinuses. This character is also found is several other superfamilies such as Neomphaloidea, Pleurotomarioidea, Fissurelloidea, and Scissurelloidea and in the families Siliquariidae and Turridae. Therefore, this characteristic is to be considered autapomorphic.
• a unique radular formula with an underlying rhipidoglossate ground plan.^[3]

Taxonomy

This superfamily was placed in part or in whole previously to 1979 either in the Archaeogastropoda near the superfamily Trochoidea or in the Caenogastropoda near the superfamily Stromboidea.^[4] In 1987 Salvini-Plawén and Haszprunar changed its status to the suborder Seguenziina, based on the radular formula that they considered to be intermediate between "rhipidoglossate" and "taenioglossate".^[5] At about the same time in 1987 Goryachev elevated the superfamily to ordinal status Seguenziiformes in the superorder Littorinimorpha, based on the taenioglossal radula.^[6]

2005 taxonomy

2005 taxonomy according to Bouchet & Rocroi, 2005. (Families that are exclusively fossil are indicated with a dagger †.)

Superfamily Seguenzioidea

Family Seguenziidae

Family Chilodontaidae

† Family Eucyclidae

† Family Laubellidae

2007–2009 taxonomy

Kano et al. (2009)^[7] elevated the subfamily Calliotropinae to the family level as the Calliotropidae, and the subfamily Cataeginae to family level as the Cataegidae.^[7]

The superfamily Seguenzioidea consists of six families:^[8]

• Cataegidae McLean & Quinn, 1987
• Chilodontaidae Wenz, 1938
• Choristellidae Bouchet & Warén, 1979
• Eucyclidae Koken, 1896
• † Eucycloscalidae Gründel, 2007
• Eudaroniidae Gründel, 2004
• † Eunemopsidae Bandel, 2010
• † Lanascalidae Bandel, 1992
• † Laubellidae Cox, 1960
• Pendromidae Warén, 1991
• † Pseudoturcicidae Bandel, 2010
• † Sabrinellidae Bandel, 2010
• Seguenziidae Verrill, 1884
• Trochaclididae Thiele, 1928

Unassigned to a family:

• • Adeuomphalus Seguenza, 1876 ^[7]
  • Aequispirella Finlay, 1924
  • Akritogyra Warén, 1992
  • Anekes Bouchet & Warén, 1979
  • Benthobrookula A. H. Clarke, 1961
  • Brookula Iredale, 1912
  • Eudaronia Cotton, 1945
  • Granigyra Dall, 1889
  • Lissotesta Iredale, 1915
  • Lissotestella Powell, 1946
  • Microcarina Laseron, 1954
  • Moelleriopsis Bush, 1897
  • Notosetia Iredale, 1915
  • Palazzia Warén, 1991
  • Putilla A. Adams, 1867
  • Retigyra Warén, 1989
  • Trenchia Knudsen, 1964
  • Ventsia Warén & Bouchet, 1993
  • Vetulonia Dall, 1913
  • Wanganella Laseron, 1954
  • Xyloskenea B. A. Marshall, 1988

Unassigned genera brought into synonymy:

• Abyssogyra A.H. Clarke, 1961: synonym of Moelleriopsis Bush, 1897
• Intortia Egorova, 1972: synonym of Lissotesta Iredale, 1915
• Molleriopsis : synonym of Moelleriopsis Bush, 1897

References

• Kano, Y. 2008: Vetigastropod phylogeny and a new concept of Seguenzioidea: Independent evolution of copulatory organs in the deep-sea habitats. Zoologica Scripta 37: 1-21
• James F. Quinn Jr., (1991), Systematic Position of Basilissopsis and Guttula, and a Discussion of the Phylogeny of the Seguenzioidea (Gastropoda: Prosobranchia), Bulletin of Marine Science, Volume 49, Numbers 1-2, September 1991, pp. 575-598(24)

Notes and References

1. Gofas, S. (2010). Seguenzioidea. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=224565 on 2011-01-09
2. Bouchet, P. . Rocroi, J.-P. . amp . 2005 . Classification and Nomenclator of Gastropod Families . Malacologia . 47 . 1–2 .
3. http://docserver.ingentaconnect.com/deliver/connect/umrsmas/00074977/v49n1/s49.pdf?expires=1369928888&id=74401970&titleid=10983&accname=Guest+User&checksum=8A1DBAA5A294BA597FCC6300E3EDAA2A James F. Quinn Jr., (1991), Systematic Position of Basilissopsis and Guttula, and a Discussion of the Phylogeny of the Seguenzioidea (Gastropoda: Prosobranchia), Bulletin of Marine Science, Volume 49, Numbers 1-2, September 1991, pp. 575-598(24)
4. Quin 1983. "A revision of the Seguenziacea Verrill, 1884 (Gastropoda: Prosobranchia). I. Summary and evaluation of the superfamily". Proc. BioI. Soc. Wash. 96(4): 725-757.
5. Salvini-Plawén and G. Haszprunar. 1987. The Vetigastropoda and the systematics of streptoneurous gastropods (Mollusca). J. Zool. (London) A211: 747-770
6. Goryachev, 1987. Ob'em i polozhenie semeistva Seguenziidae (Mollusca, Gastropoda, Seguenziidae) v klasse bryukhonogikh mollyuskov. [''The volume and the position of the family Seguenziidae (Mollusca, Gastropoda, Seguenziidae) in the gastropod class'']. Pages 21–23 in Va. I. Starobogatov, A. N. Golikov, and 1. M. Likharev, eds. Molluscs. Results and perspectives of investigation. Abstracts of communications. Zoological Institute, Akademiya Nauk SSSR, Leningrad.
7. Kano Y., Chikyu E. & Warén A. (2009) "Morphological, ecological and molecular characterization of the enigmatic planispiral snail genus Adeuomphalus (Vetigastropoda: Seguenzioidea)". Journal of Molluscan Studies 75: 397-418. .
8. http://www.marinespecies.org/aphia.php?p=taxdetails&id=224565 WoRMS : Seguenzioidea; accessed : 1 October 2010