''Acremodontina alazon'' 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
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 ...
s, 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 ...
, the false top snails.
[Rosenberg, G. (2012). ''Acremodontina alazon'' (Hedley, 1905). Accessed through: ]World Register of Marine Species
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms.
Content
The content of the registry is edited and maintained by scientific specialist ...
at http://www.marinespecies.org/aphia.php?p=taxdetails&id=594274 on 2012-12-23
Description
The height of the shell attains 1.5 mm, its major diameter 1.75 mm, its minor diameter 1.37 mm.
(Original description) The minute shell is solid. It is turbinate, elevate, tricarinate, descending at 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 ...
and narrowly umbilicate. The surface is smooth and glossy. The colour of the shell is porcelain white.
The shell contains three
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. The first forms 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 ...
. 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 ...
consists of three projecting lamellate keels revolving from the protoconch to the aperture. The third keel of the penultimate whorl is half covered by the suture of the following whorl. From the first keel, which runs along the shoulder, a nearly flat shelf extends to the suture. From the first to the third keel the side of the shell is nearly perpendicular. Around the umbilicus are three spiral cords. The aperture is oblique, angled above and rounded below. The outer
lip is neither thickened nor reflected. The umbilicus is deep, narrow and contracted by the
columella.
Hedley, C. (1905). Mollusca from one hundred and eleven fathoms, East of Cape Byron, New South Wales. Records of the Australian Museum. 6(2): 41–54.
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
External links
Marshall, B. A. (1995). Recent and Tertiary Trochaclididae from the southwest Pacific (Mollusca: Gastropoda: Trochoidea). The Veliger. 38: 92-115.
{{Taxonbar, from=Q4675085
alazon
Gastropods described in 1905
Gastropods of Australia