Astralium semicostatum

Astralium semicostatum
Drawing with two views of a shell of Astralium semicostatum
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Vetigastropoda
Order:	Trochida
Superfamily:	Trochoidea
Family:	Turbinidae
Genus:	Astralium
Species:	A. semicostatum
Binomial name
Astralium semicostatum (Kiener, 1850)
Synonyms [1]
Astraea semicostata(Kiener, 1850) Astralium semicostatum(P. Fischer, 1875) Calcar semicostatumP. Fischer, 1875 Trochus semicostatusKiener, 1850 (original combination)

Astralium semicostatum, common name the half-ribbed star shell, is a species of sea snail, a marine gastropod mollusk in the family Turbinidae, the turban snails. ^{[1] [2]}

Taxonomy

Authorship of this taxon is often attributed to Paul Fischer, who wrote the text portion of volume 11 of "Spécies général et iconographie des coquilles vivantes...". A description of this species appears on page 35 of that volume (as Calcar semicostatum; published in 1875). However, the species had been introduced earlier in the plates (pl 38, fig. 1; published in 1850 under the direction of Kiener), under the name Trochus semicostatus. ^[3]

Description

The size of the shell varies between 25 mm and 40 mm. The solid, imperforate shell has an elevated-conic shape. Its color pattern is olive-brown or cinereous. The apex is acute. The 6-7 whorls are, sharply carinated. Their upper surface is concave, longitudinally more or less finely and irregularly plicate below the sutures; coarsely plicate on the lower half of the whorls. The folds terminate in short nodes at the periphery, twelve to sixteen in number on the body whorl, and also scalloping the sutures. The base of the shell is flat, somewhat depressed around the middle, finely concentrically lirate and radiately striate. The lirae number about eight to sixteen. The suboval aperture is very oblique, white within, slightly channelled at the carina, but scarcely angulate. The short columella is bluish, rosy or white, curved, and dentate below. The base of the aperture is horizontal, sometimes with a submarginal row of minute tubercles within.

In some specimens the peripheral spines are rather long and directed outward. The lirae of the base are sometimes coarser than the figures indicate. And in fully matured individuals the outer ones become obsolete. ^[4]

Distribution

The marine species occurs off Southeast Asia.

References

1. Astralium semicostatum (Kiener, 1850) . 20 November 2025. Retrieved through: World Register of Marine Species .
2. 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.
3. MolluscaBase eds. (2025). MolluscaBase. Astralium semicostatum (P. Fischer, 1875). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=581755 on 2025-11-20
4. G.W. Tryon (1888), Manual of Conchology X; Academy of Natural Sciences, Philadelphia

• Kiener, L.C. (1850). Genre Trochus (plates only). Spécies général et iconographie des coquilles vivantes. 11. Rousseau & Baillière, Paris.

External links

• World Register of Marine Species
• "Astralium semicostatum". Gastropods.com. Retrieved 15 January 2019.