Extra extra

This article is about the mollusc. For other uses, see Extra Extra (disambiguation).

Extra extra or Marginella extra^[2] is a species of small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Some malacologists place this genus more simply in the family Marginellidae.

Extra extra
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Neogastropoda
Family:	Cystiscidae
Subfamily:	Cystiscinae
Genus:	Extra
Species:	E. extra
Binomial name
Extra extra (Jousseaume, 1894)[1]
Synonyms
Marginella extra Jousseaume, 1894[1]

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)^[3] 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; columella 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.