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Epitoniidae Berry, 1910 (1812)

Epitonium friabile

(G. B. Sowerby II, 1844)

Description:

Dimensions range from 20 mm - 25 mm high and 7.5 mm wide.
Width to height ratio: 0.38:1 ~ 0.3:1

Shell: pyramidal; thin and rather delicate; small to moderately small. Exterior colour white. About 15 whorls, convex, joined; protoconch with ~6 whorls ; teleoconch with 8-9 whorls. Spire elevated. Suture not deeply impressed. Umbilicated: very small. Approximately 36 costae on the body whorl. Costae are numerous, extremely thin and thread-like, somewhat irregularly spaced. Costae project in an acute angle near the suture. Aperture rather large, ovate; outer lip thin; inner lip slightly thickened. Operculum whitish.


Distribution:

Porpoise Head, Backstairs Passage, South Australia [Verco, 1906:145]; Swan River, Western Australia [Tryon, 1887:61]; Southern and SW Australia [Weil et al., 1999:130]


Habitat:

intertidal to 37 m [Verco, 1906:145]


Etymology:

[latin] from friabilis = brittle or easily crumbled, possibly in reference to the fragility of the shell


Type Material:

Holotype: NHMUK 1966653 [as Scalaria friabilis G.B. Sowerby II, 1844] - Locality: Swan River, Australia.. [Brown, L. & Neville, B.D., 2015]


SpeciesImage

Murrell (2025).

Woodmans Point, WA, Australia
Buried next to and feeding on anemones in sand at 3-5m
21mm

Distribution

as listed in source literature

Sowerby, G. B. II. (1844).
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Plate xxxiii. Fig. 74.
47.Sc.FRiABiLis.(pi.xxxiii.f.74.)Sow. Jun.Zool. Proc. 1844.
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pp: 95.
Original description
Sowerby, G. B. II. (1873-1874).
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Plate vii. Fig. 52.
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Species 52. (Mus. Brit.)
SCALARIA FRIABILIS.
Tryon, G.W. (1879).
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Plate 12. Fig. 75.
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pp: 61.
Clessin, S. (1897).
Shown in text as Scalaria friabilis G. B. Sowerby II, 1844
Species Image
Plate 4. Fig. 8.
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pp: 17.
Shell white, pyramidal, very thin; spire elevated; whorls close-set, convex; varices very fine, dense, spined at the suture; aperture rather large, ovate.
Verco, J.C. (1906).
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pp: pp 145.
Cotton, B.C. & Godfrey, F.K. (1931).
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pp: 5.
Kaicher, S.D. (1980).
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Card #: EP1-2329.
BMNH type collection 1966653
Murrell (2025).
Species Image
Woodmans Point, WA, Australia
Buried next to and feeding on anemones in sand at 3-5m
21mm
Species Image

Synonymy:

Scalaria friabilis G. B. Sowerby II, 1844 [in Clessin, S., 1897].
Scalaria friabilis G.B. Sowerby II, 1844 [in Brown, L. & Neville, B.D., 2015].


Source Literature:

Brown, L. & Neville, B.D. (2015). Catalog of the recent taxa of the families Epitoniidae and Nystiellidae (Mollusca: Gastropoda) with a bibliography of the descriptive and systematic literature. Zootaxa. 3907(1). Magnolia Press Auckland, New Zealand. http://dx.doi.org/10.11646/zootaxa.3907.1.1 [Accessed 22 October 2023]
Clessin, S. (1897). Die Familie der Scalariidae. In W. Kobelt (Ed.), Systematisches Conchylien-Cabinet von Martini und Chemnitz. Neu herausgegeben und vervollständigt. 2(13). Bauer & Raspe, NürnbergBauer & Raspe, Nürnberg. https://www.biodiversitylibrary.org/page/34259905 [Accessed 21 June 2025]
Cotton, B.C. & Godfrey, F.K. (1931). South Australian Shells Part II. The South Australian Naturalist. 13(1). Field Naturalists Society of South Australia. https://www.biodiversitylibrary.org/page/42129287 [Accessed 8 June 2025]
Kaicher, S.D. (1980). Epitoniidae I [Pack 23]. S. D. Kaicher, St. Petersburg, Florida. http://www.femorale.com/kaicher/species.asp?f=Epitoniidae&c=125 [Accessed 8 May 2023]
Murrell (2025). Personal Collection
Sowerby, G. B. II. (1844). Monograph of the genus Scalaria.. Thesaurus conchyliorum, or monographs of genera of shells.. 1 (4). London, privately published.. http://biodiversitylibrary.org/page/11076419 [Accessed 22 June 2023]
Sowerby, G. B. II. (1873-1874). Monograph of the genus Scalaria. Conchologia iconica, or illustrations of the shells of molluscous animals, vol. 19, pls 1-16 and unpaginated text.. 19. London. https://www.biodiversitylibrary.org/page/8217819 [Accessed 24 August 2023]
Tryon, G.W. (1887). Manual of conchology, structural and systematic with illustrations of the species. IX. Academy of Natural Sciences. https://www.biodiversitylibrary.org/page/11026889 [Accessed 20 September 2025]
Weil, A., Brown, L. & Neville, B. (1999). The Wentletrap Book. Evolver
WoRMS Editorial Board (2025). World Register of Marine Species. https://www.marinespecies.org [Accessed 8 November 2025]

WoRMS direct page link: Open WoRMS record