Nystiellidae is a family of small sea snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s, marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusks within the superfamily

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Epitonioidea

Epitonioidea

Epitonioidea is a superfamily of planktonic and ectoparasitic sea snails, marine gastropod molluscs within the informal group Ptenoglossa. This superfamily includes the wentletraps and the purple snails.-Taxonomy:...

 which includes the wentletraps, the purple snails and their allies.
This family was previously considered as a subfamily of Epitoniidae. It was raised to family status by Nützel in1998

Genera

Genera within the family Nystiellidae include: http://collections.tepapa.govt.nz/Taxon.aspx?irn=47767

• Eccliseogyra Dall, 1892
• Iphitus Jeffreys, 1883
• Murdochella
  Murdochella
  Murdochella is a genus of small sea snails, marine gastropods in the family Nystiellidae of the superfamily Epitonioidea, the wentletraps, the purple snails, and their allies...
  
  Jeffreys, 1883
• Narrimania Taviani, 1984
• Opaliopsis Thiele, 1928
• Papuliscala
  Papuliscala
  Papuliscala is a genus of small sea snails, marine gastropods in the family Nystiellidae of the superfamily Epitonioidea, the wentletraps, the purple snails, and their allies...
  
  de Boury, 1911

Genera brought into synonymy :

• Abyssiscala de Boury, 1911: synonym of Eccliseogyra Dall, 1892
• Iphitella Thiele, 1925 : synonym of Iphitus Jeffreys, 1883
• Pustuliscala de Boury, 1921 : synonym of Papuliscala de Boury, 1911
• Sculptifer Beu & Climo, 1974 : synonym of Iphitus Jeffreys, 1883
• Solutiscala de Boury, 1909 : synonym of Eccliseogyra Dall, 1892
• Stylotrochus Seguenza, 1876: synonym of Iphitus Jeffreys, 1883