Turridae
This group is well defined by its usually narrowly fusiform shell with obsolete axial sculpture and peripheral anal sinus.
The family name Turridae was originally given to a very large group of several thousand sea snail species that were thought to be closely related. The family was described with about 700 genus-group taxa and an estimated 10,000 Recent and fossil species.[2] However, that original grouping was discovered to be polyphyletic. In recent years, the family Turridae has been much reduced in size, because a number of other families were created to contain the monophyletic lineages that had previously been thought to belong in the same family.
Bouchet et al. 2011 state: Shell of medium to large size (usually 20–30 mm, up to 110 mm high), short- to high-fusiform, usually with a high spire and a long (rarely short and truncated) siphonal canal. Axial sculpture weak or absent. Anal sinus on whorl periphery. Protoconch typically multispiral, up to six whorls, protoconch I smooth, protoconch II with arcuate axial riblets; reduced paucispiral protoconch usually smooth, may have arcuate axial riblets.
In living taxa:
Operculum fully developed, with terminal nucleus. Radular formula typically 1-(1:R:1)-1. Small and narrow rachidian and plate-like laterals are fused together, together constituting a central formation of different development (Kantor, 2006), varying from a well-defined broad central tooth to a tooth clearly formed of three elements through a gradual reduction of rachidian and/or laterals to complete absence. Marginals duplex, of variable morphology, from broadly oval and flattened with nearly equally developed limbs to awl-shaped and divided only in basal part. In most cases, the major limb is large and knife-shaped, while the accessory limb is dorsal and more weakly developed. In Iotyrris, marginal teeth have equally developed limbs that form a shallow broad trough.