Extra extra

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)
Synonyms
	Marginella extra Jousseaume, 1894;

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.

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.

References

^ ^a ^b Jousseaume, F.P. (1894). "Diagnoses des coquilles de nouveaux mollusques". Bulletin de la Société Philomathique de Paris. 8 (6): 98–105. Retrieved 4 July 2020.
^ 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
^ Dautzenberg, Ph. (1929). Mollusques testaces marins de Madagascar. Faune des Colonies Françaises, Tome III