''Ivara'' is a small

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of sea snails, pyramidellid gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is es ...

s or

micromollusk A micromollusk is a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also ...

s. This genus is currently placed in the

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to confl ...

Chrysallidini Chrysallidinae is a taxonomic group of very small sea snails, marine gastropod mollusk in the family Pyramidellidae, the pyrams and their allies. Taxonomy Chrysallidinae has been one of eleven recognized subfamilies of the gastropod family ...

, of the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Odostomiidae Odostomiinae, ''Odostomia'' snails and their allies, is a taxonomic subfamily of minute parasitic sea snails. These are marine heterobranch gastropod mollusks, or micromollusks, in the family Pyramidellidae. Taxonomy The subfamily Odostomi ...

. The Brazilian species have been revised by Pimenta et al. (2009).Rosenberg, G. (2011). Ivara Arnold, 1903. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=588364 on 2012-01-05 There are both living and fossil species in this genus.

Shell description

The original description (Dall & Bartsch in Arnold 1903) is short: "''Odostomias'' characterized by the spiral striation and tabulated whorls". Arnold (1903) gives the following characterization of the type species: "Shell minute, ovate, thin; spire elevated; apex acute; whorls five, convex, shouldered above; surface sculptured by fine, spiral ridges and obsolete transverse ribs, more prominent near top of whorls; suture deeply impressed; body-whorl over half length of shell; shouldered above, evenly convex below; aperture truncated above, evenly rounded below; outer lip thin, extending around and up columella, forming a small columellar plication.Dimensions.- Long. 4 mm.; lat. 1.8 mm.; body whorl 2.6 mm.; aperture 1.5 mm. This delicate little shell is easily recognized by its shouldered whorls and delicate spiral sculpture. Specimens identified by Dr. Dall; but the species omitted from the text prepared by Dall and Bartsch. Rare in lower San Pedro series of Deadman Island. One specimen, which is figured, and is now in the collection of Delos Arnold. Living.-Mexical Coast (Dall). Pleistocene.-San Pedro (Arnold)."

Life habits

Little is known about the biology of the members of this genus. As is true of most members of the

Pyramidellidae Pyramidellidae, common name the pyram family, or pyramid shells, is a voluminous taxonomic family of mostly small and minute ectoparasitic sea snails, marine heterobranch gastropod molluscs. The great majority of species of pyrams are micr ...

sensu lato ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular c ...

'', they are

ectoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

Species

Species within the genus ''Ivara'' include: * '' Ivara dollfusi'' (Locard, 1886) * ''

Ivara terryi ''Ivara terryi'' is a species of sea snail, a marine gastropod mollusk in the family Pyramidellidae, the pyrams and their allies.Rosenberg, G. (2011). ''Ivara terryi'' (Olsson & McGinty, 1958). Accessed through: World Register of Marine Species ...

'' (Olsson & McGinty, 1958) * '' Ivara turricula'' (Dall & Bartsch in Arnold, 1903) - as ''Odostomia turricula'' - type species

References

This article incorporates public domain text from the reference {{Taxonbar, from=Q6098489 Pyramidellidae