Extra extra

Extra extra
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Caenogastropoda clade Hypsogastropoda clade Neogastropoda
Superfamily:	Muricoidea
Family:	Cystiscidae / Marginellidae
Subfamily:	Cystiscinae
Genus:	Extra / Marginella Jousseaume, 1894
Species:	E. extra / M. extra
Binomial name
Extra extra (Jousseaume, 1894)
Synonyms
Marginella extra Jousseaume, 1894

Extra extra or Marginella extra^[1] is a species of minute sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Some malacologists place this genus more simply in the family Marginellidae.

Taxonomy

Marginella extra was originally described under name Extra extra by French zoologist Félix Pierre Jousseaume in 1894. He placed this species to the monotypic genus Extra Jousseaume, 1894. Dautzenberg (1929)^[2] moved this species into genus Marginella.

Diagnosis

The shell is minute, white, semitranslucent; prominent axial costae present; spire sunken but not immersed; lip strongly thickened, smooth, lacking denticulation, flared posteriorly; siphonal notch absent; posterior notch absent; distinct parietal callus "shield" present; collumela multiplicate, with 5 plications plus parietal lirae, plications slightly excavated inside aperture due to parietal callus deposits.

Distribution and habitat

Recorded only from western Indian Ocean along Madagascar, apparently in shallow water.

References

1. ^ WoRMS (2009). Extra extra (Jousseaume, 1894). Accessed through the World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=217193 on 4 December 2010
2. ^ Dautzenberg, Ph. (1929). Mollusques testaces marins de Madagascar. Faune des Colonies Françaises, Tome III

• Coovert G. A. & Coovert H. K. (1995). "Revision of the Supraspecific Classification of Marginelliform Gastrapods". The Nautilus 109(2 & 3):43-110.

External links