''Sinezona brevis'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of minute

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc 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 esti ...

in the

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

Scissurellidae.Bouchet, P. (2013). Sinezona brevis (Hedley, 1904). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=492810 on 2013-03-23

Description

The white shell reaches a height of 1 mm. The solid shell has a depressed, turbinate shape. It is openly perforate to imperforate. The

sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...

shows distant longitudinal lamellate ribs that cross the

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

from the suture to the umbilicus. Their interstices contain raised spiral threads, which grow coarser on approaching the umbilicus. The

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...

contains 1½

, concluding with a prominent varix. The three whorls are tabulate above, and rounded below. The

body whorl The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

descends rapidly. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

is roundly ovate. The sharp outer lip is convex. The inner lip spreads as a distinct callosity over the body, and sometimes seals the umbilicus partly or wholly up. The columella is concave. The narrow umbilicus is deep, and is bordered with a raised ridge, or is closed up. The foramen is large, and distant from the margin, to which a furrow joins it. The fasciole is extremity short, terminating half a whorl behind the aperture. it is bordered by keels and is traversed by lamellae, which correspond to the longitudinal ribs.Suter H. (1913-1915), Manual of new Zealand Mollusca; Wellington, N. Z. :J. Mackay, govt. printer,1913-1915
/ref>

Distribution

This marine species occurs off

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

References

* Powell A. W. B., ''New Zealand Mollusca'', William Collins Publishers Ltd, Auckland, New Zealand 1979 * Marshall,B. A., 2002. ''Some recent scissurellids from the New Zealand region and remarks on some scissurellid genus group names (Mollusca:Gastropoda:Vestigastropoda)''. Molluscan Research 22:165-181 * Geiger D.L. (2012) ''Monograph of the little slit shells. Volume 1. Introduction, Scissurellidae. pp. 1-728. Volume 2. Anatomidae, Larocheidae, Depressizonidae, Sutilizonidae, Temnocinclidae''. pp. 729–1291. Santa Barbara Museum of Natural History Monographs Number 7

External links

* {{Taxonbar, from=Q1318212 Scissurellidae Gastropods of New Zealand Gastropods described in 1904