''Bellastraea rutidoloma'', common name the granular small star, 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 ...

Turbinidae, the turban snails.

Description

(Original description by R. Tate) The shell has a lenticular-conoid shape, about equally sloping above and below from the angular periphery. The 4½

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 are flat. The embryonic contains 1½ whorls fimbriated at the suture. The umbilicus is minute. The upper surface of 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 ...

shows a stout and a broad lira next to the suture, which is transversely crenulate-ridged. The periphery is bluntly angled by a slightly compressed convex keel, which is obsoletely crenulated. Between the keel and the sutural band are three granulose lirae about equidistant and equal-sized but the anterior one is close to the keel (in older specimens a small lira is interposed next the suture, and there is a tendency in the granules of the lirae to become somewhat confluent). The intervals between the lirae are smooth. The base has four granulose lirae. The umbilical region is bounded by a broad ridge, which is broken up into claviform tubercles obliquely disposed. The colour is greenish-brown in living specimens, flesh-coloured with rufous lirae and darker tinted at the suture and keel in beach examples. The interior of 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 ...

of living examples is greenish and of a pearly lustre.Transactions of the Royal Society of South Australia v.17 (1892–1893)
/ref>

Distribution

This marine species is endemic to Australia and occurs off

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

References

* Cotton, B.C. 1959. ''South Australian Mollusca. Archaeogastropoda. Handbook of the Flora and Fauna of South Australia.'' Adelaide : South Australian Government Printer 449 pp * 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. * Alf A. & Kreipl K. (2011) ''The family Turbinidae. Subfamilies Turbininae Rafinesque, 1815 and Prisogasterinae Hickman & McLean, 1990''. In: G.T. Poppe & K. Groh (eds), A Conchological Iconography. Hackenheim: Conchbooks. pp. 1–82, pls 104–245. Turbinidae Gastropods described in 1893 {{Turbinidae-stub