''Astraea heliotropium'', common name the sunburst star turban or the circular saw shell, is a large

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 ...

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 ...

of 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 ...

Turbinidae Turbinidae, the turban snails, are a family of small to large marine gastropod molluscs in the superfamily Trochoidea.Bouchet, P. (2014). Turbinidae Rafinesque, 1815. Accessed through: World Register of Marine Species at http://www.marinespecie ...

, the turbans and star snails.WoRMS (2010). ''Astraea heliotropium'' (Martyn, 1784). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=404992 on 2011-03-08 This large species was brought to Europe for the first time by the famous

Captain Cook James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean an ...

Shell description

The height of the shell is up to 60 mm, and the width is up to 120 mm. The large shell has a depressed-conic shape. Below widely it is umbilicate and concave. The

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...

is dome-shaped, and consists of 5 convex

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 suture is rendered zigzag by the prominent compressed triangular recurved vaulted spines which arm the acutely carinated periphery. The whorls above and below contain numerous spiral series of granules. The wide umbilicus is deep, and coarsely obliquely striate within. 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 transversely oval, oblique, pearly within. The

peristome Peristome (from the Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mosses In mosse ...

is continuous. The columella is slightly dilated, impinging upon the umbilicus. The color pattern is brownish or purplish above, light below.G.W. Tryon (1888), Manual of Conchology X; Academy of Natural Sciences, Philadelphia
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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 New Zealand.

References

* Williams, S.T. (2007). ''Origins and diversification of Indo-West Pacific marine fauna: evolutionary history and biogeography of turban shells (Gastropoda, Turbinidae)''. Biological Journal of the Linnean Society, 2007, 92, 573–592. * Spencer, H.; Marshall. B. (2009). ''All Mollusca except Opisthobranchia''. In: Gordon, D. (Ed.) (2009). New Zealand Inventory of Biodiversity. Volume One: Kingdom Animalia. 584 pp

External links

* {{Taxonbar, from=Q4811184

heliotropium ''Heliotropium'' is a genus of flowering plants in the heliotrope family, Heliotropiaceae. There are around 325 species in this almost cosmopolitan genus, which are commonly known as heliotropes (sg. ). It is highly toxic for dogs and cats. Et ...

Endemic fauna of New Zealand Gastropods described in 1784 Endemic molluscs of New Zealand

Shell description

Distribution

References

Further reading

External links