''Pleurotomella amplecta'' 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 ...

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

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 ...

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 e ...

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 ...

Raphitomidae Raphitomidae is a family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families". ''Malacologia'' 47(1-2). . 39 ...

.MolluscaBase (2019). Pleurotomella amplecta (Hedley, 1922). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=868142 on 2019-02-03

Description

The length of the shell attains 12 mm, its diameter 5 mm. (Original description) The shell is fusiform. It contains nine

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 ...

s, including 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 ...

. Its colour is dull white. The protoconch consists of two rounded microscopically spirally grooved whorls.

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 ...

: On the first adult whorl there are nine or ten radials, which decrease to six on the lower whorls. These are discontinuous, prominent, vertical, ceasing at the fasciole and on the base. The spirals are evenly spaced, sharp, elevated, overriding and denticulating the ribs, increasing by intercalation from two above to about eighteen below. These are again traversed by a secondary sculpture of fine radiating threads. The fasciole is broad, excavate, crossed by close, sharp, and crescentic lamella. 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 imperfect in the holotype. The

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...

is slightly twisted. Hedley, C. 1922. A revision of the Australian Turridae. Records of the Australian Museum 13(6): 213-359, pls 42-56

Distribution

This marine species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to Australia and occurs off

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

References

* Laseron, C. 1954. ''Revision of the New South Wales Turridae (Mollusca).'' Australian Zoological Handbook. Sydney : Royal Zoological Society of New South Wales pp. 56, pls 1–12. * Powell, A.W.B. 1966. ''The molluscan families Speightiidae and Turridae, an evaluation of the valid taxa, both Recent and fossil, with list of characteristic species.'' Bulletin of the Auckland Institute and Museum. Auckland, New Zealand 5: 1–184, pls 1–23 * Beu, A.G. 2011 ''Marine Molluscs of oxygen isotope stages of the last 2 million years in New Zealand. Part 4. Gastropoda (Ptenoglossa, Neogastropoda, Heterobranchia).'' Journal of the Royal Society of New Zealand 41, 1–153

External links

*
Brazier, J. 1876. ''A list of the Pleurotomidae collected during the Chevert expedition, with the description of the new species''. Proceedings of the Linnean Society of New South Wales 1: 151–162
{{DEFAULTSORT:Pleurotomella Amplecta amplecta Gastropods described in 1922 Gastropods of Australia